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* [PATCH v30 00/20] Intel SGX foundations
@ 2020-05-15  0:43 Jarkko Sakkinen
  2020-05-15  0:43 ` [PATCH v30 01/20] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
                   ` (20 more replies)
  0 siblings, 21 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-15  0:43 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: akpm, dave.hansen, sean.j.christopherson, nhorman, npmccallum,
	haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp, josh, luto,
	kai.huang, rientjes, cedric.xing, puiterwijk, Jarkko Sakkinen

Intel(R) SGX is a set of CPU instructions that can be used by applications
to set aside private regions of code and data. The code outside the enclave
is disallowed to access the memory inside the enclave by the CPU access
control.

There is a new hardware unit in the processor called Memory Encryption
Engine (MEE) starting from the Skylake microacrhitecture. BIOS can define
one or many MEE regions that can hold enclave data by configuring them with
PRMRR registers.

The MEE automatically encrypts the data leaving the processor package to
the MEE regions. The data is encrypted using a random key whose life-time
is exactly one power cycle.

The current implementation requires that the firmware sets
IA32_SGXLEPUBKEYHASH* MSRs as writable so that ultimately the kernel can
decide what enclaves it wants run. The implementation does not create
any bottlenecks to support read-only MSRs later on.

You can tell if your CPU supports SGX by looking into /proc/cpuinfo:

	cat /proc/cpuinfo  | grep sgx

v30:
Bunch of tags added. No actual code changes.

v29:
* The selftest has been moved to selftests/sgx. Because SGX is an execution
  environment of its own, it really isn't a great fit with more "standard"
  x86 tests.

  The RSA key is now generated on fly and the whole signing process has
  been made as part of the enclave loader instead of signing the enclave
  during the compilation time.

  Finally, the enclave loader loads now the test enclave directly from its
  ELF file, which means that ELF file does not need to be coverted as raw
  binary during the build process.
* Version the mm_list instead of using on synchronize_mm() when adding new
  entries. We hold the write lock for the mm_struct, and dup_mm() can thus
  deadlock with the page reclaimer, which could hold the lock for the old
  mm_struct.
* Disallow mmap(PROT_NONE) from /dev/sgx. Any mapping (e.g. anonymous) can
  be used to reserve the address range. Now /dev/sgx supports only opaque
  mappings to the (initialized) enclave data.
* Make the vDSO callable directly from C by preserving RBX and taking leaf
  from RCX.

v28:
* Documented to Documentation/x86/sgx.rst how the kernel manages the
  enclave ownership.
* Removed non-LC flow from sgx_einit().
* Removed struct sgx_einittoken since only the size of the corresponding
  microarchitectural structure is used in the series ATM.

v27:
* Disallow RIE processes to use enclaves as there could a permission
  conflict between VMA and enclave permissions.
* In the documentation, replace "grep /proc/cpuinfo" with
  "grep sgx /proc/cpuinfo".

v26:
* Fixed the commit author in "x86/sgx: Linux Enclave Driver", which was
  changed in v25 by mistake.
* Addressed a bunch of grammar mistakes in sgx.rst (thanks Randy once
  again for such a detailed feedback).
* Added back the MAINTAINERS update commit, which was mistakenly removed
  in v25.
* EREMOVE's for SECS cannot be done while sanitizing an EPC section. The
  CPU does not allow to remove a SECS page before all of its children have
  been removed, and a child page can be in some other section than the one
  currently being processed. Thus, removed special SECS processing from
  sgx_sanitize_page() and instead put sections through it twice. In the
  2nd round the lists should only contain SECS pages.

v25:
* Fix a double-free issue when SGX_IOC_ENCLAVE_ADD_PAGES
  fails on executing ENCLS[EADD]. The rollback path executed
  radix_tree_delete() on the same address twice when this happened.
* Return -EINTR instead of -ERESTARTSYS in SGX_IOC_ENCLAVE_ADD_PAGES when
  a signal is pending.
* As requested by Borislav, move the CPUID 0x12 features to their own word
  in cpufeatures.
* Sean fixed a bug from sgx_reclaimer_write() where sgx_encl_put_backing()
  was called with an uninitialized pointer when sgx_encl_get_backing()
  fails.
* Migrated /dev/sgx/* to misc. This is future-proof as struct miscdevice
  has 'groups' for setting up sysfs attributes for the device.
* Use device_initcall instead of subsys_initcall so that misc_class is
  initialized before SGX is initialized.
* Return -EACCES in SGX_IOC_ENCLAVE_INIT when caller tries to select
  enclave attributes that we the kernel does not allow it to set instead
  of -EINVAL.
* Unless SGX public key MSRs are writable always deny the feature from
  Linux. Previously this was only denied from driver. How VMs should be
  supported is not really part of initial patch set, which makes this
  an obvious choice.
* Cleaned up and refined documentation to be more approachable.

v24:
* Reclaim unmeasured and TCS pages (regression in v23).
* Replace usages of GFP_HIGHUSER with GFP_KERNEL.
* Return -EIO on when EADD or EEXTEND fails in %SGX_IOC_ENCLAVE_ADD_PAGES
  and use the same rollback (destroy enclave). This can happen when host
  suspends itself unknowingly to a VM running enclaves. From -EIO the user
  space can deduce what happened.
* Have a separate @count in struct sgx_enclave_add_pages to output number
  of bytes processed instead of overwriting the input parameters for
  clarity and more importantly that the API provides means for partial
  processing (@count could be less than @length in success case).

v23:
* Replace SGX_ENCLAVE_ADD_PAGE with SGX_ENCLAVE_ADD_PAGES. Replace @mrmask
  with %SGX_PAGE_MEASURE flag.
* Return -EIO instead of -ECANCELED when ptrace() fails to read a TCS page.
* In the reclaimer, pin page before ENCLS[EBLOCK] because pinning can fail
  (because of OOM) even in legit behaviour and after EBLOCK the reclaiming
  flow can be only reverted by killing the whole enclave.
* Fixed SGX_ATTR_RESERVED_MASK. Bit 7 was marked as reserved while in fact
  it should have been bit 6 (Table 37-3 in the SDM).
* Return -EPERM from SGX_IOC_ENCLAVE_INIT when ENCLS[EINIT] returns an SGX
  error code.

v22:
* Refined bunch commit messages and added associated SDM references as
  many of them were too exhausting and some outdated.
* Alignment checks have been removed from mmap() because it does not define
  the ELRANGE. VMAs only act as windows to the enclave. The semantics
  compare somewhat how mmap() works with regular files.
* We now require user space addresses given to SGX_IOC_ENCLAVE_ADD_PAGE to be
  page aligned so that we can pass the page directly to EADD and do not have
  to do an extra copy. This was made effectively possible by removing the
  worker thread for adding pages.
* The selftest build files have been refined throughout of various glitches
  and work properly in a cross compilation environment such as BuildRoot.
  In addition, libcalls fail the build with an assertion in the linker
  script, if they end up to the enclave binary.
* CONFIG_INTEL_SGX_DRIVER has been removed because you cannot use SGX core
  for anything without having the driver. This could change when KVM support
  is added.
* We require zero permissions in SECINFO for TCS pages because the CPU
  overwrites SECINFO flags with zero permissions and measures the page
  only after that. Allowing to pass TCS with non-zero permissions would
  cause mismatching measurement between the one provided in SIGSTRUCT and
  the one computed by the CPU.
* Obviously lots of small fixes and clean ups (does make sense to
  document them all).

v21:
* Check on mmap() that the VMA does cover an area that does not have
  enclave pages. Only mapping with PROT_NONE can do that to reserve
  initial address space for an enclave.
* Check om mmap() and mprotect() that the VMA permissions do not
  surpass the enclave permissions.
* Remove two refcounts from vma_close(): mm_list and encl->refcount.
  Enclave refcount is only need for swapper/enclave sync and we can
  remove mm_list refcount by destroying mm_struct when the process
  is closed. By not having vm_close() the Linux MM can merge VMAs.
* Do not naturally align MAP_FIXED address.
* Numerous small fixes and clean ups.
* Use SRCU for synchronizing the list of mm_struct's.
* Move to stack based call convention in the vDSO.

v20:
* Fine-tune Kconfig messages and spacing and remove MMU_NOTIFIER
  dependency as MMU notifiers are no longer used in the driver.
* Use mm_users instead of mm_count as refcount for mm_struct as mm_count
  only protects from deleting mm_struct, not removing its contents.
* Sanitize EPC when the reclaimer thread starts by doing EREMOVE for all
  of them. They could be in initialized state when the kernel starts
  because it might be spawned by kexec().
* Documentation overhaul.
* Use a device /dev/sgx/provision for delivering the provision token
  instead of securityfs.
* Create a reference to the enclave when already when opening
  /dev/sgx/enclave.  The file is then associated with this enclave only.
  mmap() can be done at free at any point and always get a reference to
  the enclave. To summarize the file now represents the enclave.

v19:
* Took 3-4 months but in some sense this was more like a rewrite of most
  of the corners of the source code. If I've forgotten to deal with some
  feedback, please don't shout me. Make a remark and I will fix it for
  the next version. Hopefully there won't be this big turnovers anymore.
* Validate SECS attributes properly against CPUID given attributes and
  against allowed attributes. SECS attributes are the ones that are
  enforced whereas SIGSTRUCT attributes tell what is required to run
  the enclave.
* Add KSS (Key Sharing Support) to the enclave attributes.
* Deny MAP_PRIVATE as an enclave is always a shared memory entity.
* Revert back to shmem backing storage so that it can be easily shared
  by multiple processes.
* Split the recognization of an ENCLS leaf failure by using three
  functions to detect it: encsl_faulted(), encls_returned_code() and
  sgx_failed(). encls_failed() is only caused by a spurious expections that
  should never happen. Thus, it is not defined as an inline function in
  order to easily insert a kprobe to it.
* Move low-level enclave management routines, page fault handler and page
  reclaiming routines from driver to the core. These cannot be separated
  from each other as they are heavily interdependent. The rationale is that
  the core does not call any code from the driver.
* Allow the driver to be compiled as a module now that it no code is using
  its routines and it only uses exported symbols. Now the driver is
  essentially just a thin ioctl layer.
* Reworked the driver to maintain a list of mm_struct's. The VMA callbacks
  add new entries to this list as the process is forked. Each entry has
  its own refcount because they have a different life-cycle as the enclave
  does. In effect @tgid and @mm have been removed from struct sgx_encl
  and we allow forking by removing VM_DONTCOPY from vm flags.
* Generate a cpu mask in the reclaimer from the cpu mask's of all
  mm_struct's. This will kick out the hardware threads out of the enclave
  from multiple processes. It is not a local variable because it would
  eat too much of the stack space but instead a field in struct
  sgx_encl.
* Allow forking i.e. remove VM_DONTCOPY. I did not change the API
  because the old API scaled to the workload that Andy described. The
  codebase is now mostly API independent i.e. changing the API is a
  small task. For me the proper trigger to chanage it is a as concrete
  as possible workload that cannot be fulfilled. I hope you understand
  my thinking here. I don't want to change anything w/o proper basis
  but I'm ready to change anything if there is a proper basis. I do
  not have any kind of attachment to any particular type of API.
* Add Sean's vDSO ENCLS(EENTER) patches and update selftest to use the
  new vDSO.

v18:
* Update the ioctl-number.txt.
* Move the driver under arch/x86.
* Add SGX features (SGX, SGX1, SGX2) to the disabled-features.h.
* Rename the selftest as test_sgx (previously sgx-selftest).
* In order to enable process accounting, swap EPC pages and PCMD's to a VMA
  instead of shmem.
* Allow only to initialize and run enclaves with a subset of
  {DEBUG, MODE64BIT} set.
* Add SGX_IOC_ENCLAVE_SET_ATTRIBUTE to allow an enclave to have privileged
  attributes e.g. PROVISIONKEY.

v17:
* Add a simple selftest.
* Fix a null pointer dereference to section->pages when its
  allocation fails.
* Add Sean's description of the exception handling to the documentation.

v16:
* Fixed SOB's in the commits that were a bit corrupted in v15.
* Implemented exceptio handling properly to detect_sgx().
* Use GENMASK() to define SGX_CPUID_SUB_LEAF_TYPE_MASK.
* Updated the documentation to use rst definition lists.
* Added the missing Documentation/x86/index.rst, which has a link to
  intel_sgx.rst. Now the SGX and uapi documentation is properly generated
  with 'make htmldocs'.
* While enumerating EPC sections, if an undefined section is found, fail
  the driver initialization instead of continuing the initialization.
* Issue a warning if there are more than %SGX_MAX_EPC_SECTIONS.
* Remove copyright notice from arch/x86/include/asm/sgx.h.
* Migrated from ioremap_cache() to memremap().

v15:
* Split into more digestable size patches.
* Lots of small fixes and clean ups.
* Signal a "plain" SIGSEGV on an EPCM violation.

v14:
* Change the comment about X86_FEATURE_SGX_LC from “SGX launch
  configuration” to “SGX launch control”.
* Move the SGX-related CPU feature flags as part of the Linux defined
  virtual leaf 8.
* Add SGX_ prefix to the constants defining the ENCLS leaf functions.
* Use GENMASK*() and BIT*() in sgx_arch.h instead of raw hex numbers.
* Refine the long description for CONFIG_INTEL_SGX_CORE.
* Do not use pr_*_ratelimited()  in the driver. The use of the rate limited
  versions is legacy cruft from the prototyping phase.
* Detect sleep with SGX_INVALID_EINIT_TOKEN instead of counting power
  cycles.
* Manually prefix with “sgx:” in the core SGX code instead of redefining
  pr_fmt.
* Report if IA32_SGXLEPUBKEYHASHx MSRs are not writable in the driver
  instead of core because it is a driver requirement.
* Change prompt to bool in the entry for CONFIG_INTEL_SGX_CORE because the
  default is ‘n’.
* Rename struct sgx_epc_bank as struct sgx_epc_section in order to match
  the SDM.
* Allocate struct sgx_epc_page instances one at a time.
* Use “__iomem void *” pointers for the mapped EPC memory consistently.
* Retry once on SGX_INVALID_TOKEN in sgx_einit() instead of counting power
  cycles.
* Call enclave swapping operations directly from the driver instead of
  calling them .indirectly through struct sgx_epc_page_ops because indirect
  calls are not required yet as the patch set does not contain the KVM
  support.
* Added special signal SEGV_SGXERR to notify about SGX EPCM violation
  errors.

v13:
* Always use SGX_CPUID constant instead of a hardcoded value.
* Simplified and documented the macros and functions for ENCLS leaves.
* Enable sgx_free_page() to free active enclave pages on demand
  in order to allow sgx_invalidate() to delete enclave pages.
  It no longer performs EREMOVE if a page is in the process of
  being reclaimed.
* Use PM notifier per enclave so that we don't have to traverse
  the global list of active EPC pages to find enclaves.
* Removed unused SGX_LE_ROLLBACK constant from uapi/asm/sgx.h
* Always use ioremap() to map EPC banks as we only support 64-bit kernel.
* Invalidate IA32_SGXLEPUBKEYHASH cache used by sgx_einit() when going
  to sleep.

v12:
* Split to more narrow scoped commits in order to ease the review process and
  use co-developed-by tag for co-authors of commits instead of listing them in
  the source files.
* Removed cruft EXPORT_SYMBOL() declarations and converted to static variables.
* Removed in-kernel LE i.e. this version of the SGX software stack only
  supports unlocked IA32_SGXLEPUBKEYHASHx MSRs.
* Refined documentation on launching enclaves, swapping and enclave
  construction.
* Refined sgx_arch.h to include alignment information for every struct that
  requires it and removed structs that are not needed without an LE.
* Got rid of SGX_CPUID.
* SGX detection now prints log messages about firmware configuration issues.

v11:
* Polished ENCLS wrappers with refined exception handling.
* ksgxswapd was not stopped (regression in v5) in
  sgx_page_cache_teardown(), which causes a leaked kthread after driver
  deinitialization.
* Shutdown sgx_le_proxy when going to suspend because its EPC pages will be
  invalidated when resuming, which will cause it not function properly
  anymore.
* Set EINITTOKEN.VALID to zero for a token that is passed when
  SGXLEPUBKEYHASH matches MRSIGNER as alloc_page() does not give a zero
  page.
* Fixed the check in sgx_edbgrd() for a TCS page. Allowed to read offsets
  around the flags field, which causes a #GP. Only flags read is readable.
* On read access memcpy() call inside sgx_vma_access() had src and dest
  parameters in wrong order.
* The build issue with CONFIG_KASAN is now fixed. Added undefined symbols
  to LE even if “KASAN_SANITIZE := false” was set in the makefile.
* Fixed a regression in the #PF handler. If a page has
  SGX_ENCL_PAGE_RESERVED flag the #PF handler should unconditionally fail.
  It did not, which caused weird races when trying to change other parts of
  swapping code.
* EPC management has been refactored to a flat LRU cache and moved to
  arch/x86. The swapper thread reads a cluster of EPC pages and swaps all
  of them. It can now swap from multiple enclaves in the same round.
* For the sake of consistency with SGX_IOC_ENCLAVE_ADD_PAGE, return -EINVAL
  when an enclave is already initialized or dead instead of zero.

v10:
* Cleaned up anon inode based IPC between the ring-0 and ring-3 parts
  of the driver.
* Unset the reserved flag from an enclave page if EDBGRD/WR fails
  (regression in v6).
* Close the anon inode when LE is stopped (regression in v9).
* Update the documentation with a more detailed description of SGX.

v9:
* Replaced kernel-LE IPC based on pipes with an anonymous inode.
  The driver does not require anymore new exports.

v8:
* Check that public key MSRs match the LE public key hash in the
  driver initialization when the MSRs are read-only.
* Fix the race in VA slot allocation by checking the fullness
  immediately after succeesful allocation.
* Fix the race in hash mrsigner calculation between the launch
  enclave and user enclaves by having a separate lock for hash
  calculation.

v7:
* Fixed offset calculation in sgx_edbgr/wr(). Address was masked with PAGE_MASK
  when it should have been masked with ~PAGE_MASK.
* Fixed a memory leak in sgx_ioc_enclave_create().
* Simplified swapping code by using a pointer array for a cluster
  instead of a linked list.
* Squeezed struct sgx_encl_page to 32 bytes.
* Fixed deferencing of an RSA key on OpenSSL 1.1.0.
* Modified TC's CMAC to use kernel AES-NI. Restructured the code
  a bit in order to better align with kernel conventions.

v6:
* Fixed semaphore underrun when accessing /dev/sgx from the launch enclave.
* In sgx_encl_create() s/IS_ERR(secs)/IS_ERR(encl)/.
* Removed virtualization chapter from the documentation.
* Changed the default filename for the signing key as signing_key.pem.
* Reworked EPC management in a way that instead of a linked list of
  struct sgx_epc_page instances there is an array of integers that
  encodes address and bank of an EPC page (the same data as 'pa' field
  earlier). The locking has been moved to the EPC bank level instead
  of a global lock.
* Relaxed locking requirements for EPC management. EPC pages can be
  released back to the EPC bank concurrently.
* Cleaned up ptrace() code.
* Refined commit messages for new architectural constants.
* Sorted includes in every source file.
* Sorted local variable declarations according to the line length in
  every function.
* Style fixes based on Darren's comments to sgx_le.c.

v5:
* Described IPC between the Launch Enclave and kernel in the commit messages.
* Fixed all relevant checkpatch.pl issues that I have forgot fix in earlier
  versions except those that exist in the imported TinyCrypt code.
* Fixed spelling mistakes in the documentation.
* Forgot to check the return value of sgx_drv_subsys_init().
* Encapsulated properly page cache init and teardown.
* Collect epc pages to a temp list in sgx_add_epc_bank
* Removed SGX_ENCLAVE_INIT_ARCH constant.

v4:
* Tied life-cycle of the sgx_le_proxy process to /dev/sgx.
* Removed __exit annotation from sgx_drv_subsys_exit().
* Fixed a leak of a backing page in sgx_process_add_page_req() in the
  case when vm_insert_pfn() fails.
* Removed unused symbol exports for sgx_page_cache.c.
* Updated sgx_alloc_page() to require encl parameter and documented the
  behavior (Sean Christopherson).
* Refactored a more lean API for sgx_encl_find() and documented the behavior.
* Moved #PF handler to sgx_fault.c.
* Replaced subsys_system_register() with plain bus_register().
* Retry EINIT 2nd time only if MSRs are not locked.

v3:
* Check that FEATURE_CONTROL_LOCKED and FEATURE_CONTROL_SGX_ENABLE are set.
* Return -ERESTARTSYS in __sgx_encl_add_page() when sgx_alloc_page() fails.
* Use unused bits in epc_page->pa to store the bank number.
* Removed #ifdef for WQ_NONREENTRANT.
* If mmu_notifier_register() fails with -EINTR, return -ERESTARTSYS.
* Added --remove-section=.got.plt to objcopy flags in order to prevent a
  dummy .got.plt, which will cause an inconsistent size for the LE.
* Documented sgx_encl_* functions.
* Added remark about AES implementation used inside the LE.
* Removed redundant sgx_sys_exit() from le/main.c.
* Fixed struct sgx_secinfo alignment from 128 to 64 bytes.
* Validate miscselect in sgx_encl_create().
* Fixed SSA frame size calculation to take the misc region into account.
* Implemented consistent exception handling to __encls() and __encls_ret().
* Implemented a proper device model in order to allow sysfs attributes
  and in-kernel API.
* Cleaned up various "find enclave" implementations to the unified
  sgx_encl_find().
* Validate that vm_pgoff is zero.
* Discard backing pages with shmem_truncate_range() after EADD.
* Added missing EEXTEND operations to LE signing and launch.
* Fixed SSA size for GPRS region from 168 to 184 bytes.
* Fixed the checks for TCS flags. Now DBGOPTIN is allowed.
* Check that TCS addresses are in ELRANGE and not just page aligned.
* Require kernel to be compiled with X64_64 and CPU_SUP_INTEL.
* Fixed an incorrect value for SGX_ATTR_DEBUG from 0x01 to 0x02.

v2:
* get_rand_uint32() changed the value of the pointer instead of value
  where it is pointing at.
* Launch enclave incorrectly used sigstruct attributes-field instead of
  enclave attributes-field.
* Removed unused struct sgx_add_page_req from sgx_ioctl.c
* Removed unused sgx_has_sgx2.
* Updated arch/x86/include/asm/sgx.h so that it provides stub
  implementations when sgx in not enabled.
* Removed cruft rdmsr-calls from sgx_set_pubkeyhash_msrs().
* return -ENOMEM in sgx_alloc_page() when VA pages consume too much space
* removed unused global sgx_nr_pids
* moved sgx_encl_release to sgx_encl.c
* return -ERESTARTSYS instead of -EINTR in sgx_encl_init()


Jarkko Sakkinen (10):
  x86/sgx: Add SGX microarchitectural data structures
  x86/sgx: Add wrappers for ENCLS leaf functions
  x86/sgx: Add functions to allocate and free EPC pages
  x86/sgx: Linux Enclave Driver
  x86/sgx: Add provisioning
  x86/sgx: Add a page reclaimer
  x86/sgx: ptrace() support for the SGX driver
  selftests/x86: Add a selftest for SGX
  docs: x86/sgx: Document SGX micro architecture and kernel internals
  x86/sgx: Update MAINTAINERS

Sean Christopherson (10):
  x86/cpufeatures: x86/msr: Add Intel SGX hardware bits
  x86/cpufeatures: x86/msr: Intel SGX Launch Control hardware bits
  x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX
  x86/cpu/intel: Detect SGX support
  x86/sgx: Enumerate and track EPC sections
  mm: Introduce vm_ops->may_mprotect()
  x86/vdso: Add support for exception fixup in vDSO functions
  x86/fault: Add helper function to sanitize error code
  x86/traps: Attempt to fixup exceptions in vDSO before signaling
  x86/vdso: Implement a vDSO for Intel SGX enclave call

 .../userspace-api/ioctl/ioctl-number.rst      |   1 +
 Documentation/x86/index.rst                   |   1 +
 Documentation/x86/sgx.rst                     | 206 +++++
 MAINTAINERS                                   |  11 +
 arch/x86/Kconfig                              |  14 +
 arch/x86/entry/vdso/Makefile                  |   8 +-
 arch/x86/entry/vdso/extable.c                 |  46 +
 arch/x86/entry/vdso/extable.h                 |  29 +
 arch/x86/entry/vdso/vdso-layout.lds.S         |   9 +-
 arch/x86/entry/vdso/vdso.lds.S                |   1 +
 arch/x86/entry/vdso/vdso2c.h                  |  58 +-
 arch/x86/entry/vdso/vsgx_enter_enclave.S      | 131 +++
 arch/x86/include/asm/cpufeature.h             |   5 +-
 arch/x86/include/asm/cpufeatures.h            |   8 +-
 arch/x86/include/asm/disabled-features.h      |  18 +-
 arch/x86/include/asm/enclu.h                  |   8 +
 arch/x86/include/asm/msr-index.h              |   8 +
 arch/x86/include/asm/required-features.h      |   2 +-
 arch/x86/include/asm/traps.h                  |   1 +
 arch/x86/include/asm/vdso.h                   |   5 +
 arch/x86/include/uapi/asm/sgx.h               | 175 ++++
 arch/x86/kernel/cpu/Makefile                  |   1 +
 arch/x86/kernel/cpu/common.c                  |   4 +
 arch/x86/kernel/cpu/feat_ctl.c                |  32 +-
 arch/x86/kernel/cpu/sgx/Makefile              |   6 +
 arch/x86/kernel/cpu/sgx/arch.h                | 343 ++++++++
 arch/x86/kernel/cpu/sgx/driver.c              | 209 +++++
 arch/x86/kernel/cpu/sgx/driver.h              |  32 +
 arch/x86/kernel/cpu/sgx/encl.c                | 755 +++++++++++++++++
 arch/x86/kernel/cpu/sgx/encl.h                | 128 +++
 arch/x86/kernel/cpu/sgx/encls.h               | 238 ++++++
 arch/x86/kernel/cpu/sgx/ioctl.c               | 800 ++++++++++++++++++
 arch/x86/kernel/cpu/sgx/main.c                | 280 ++++++
 arch/x86/kernel/cpu/sgx/reclaim.c             | 471 +++++++++++
 arch/x86/kernel/cpu/sgx/sgx.h                 | 108 +++
 arch/x86/kernel/traps.c                       |  14 +
 arch/x86/mm/fault.c                           |  45 +-
 include/linux/mm.h                            |   2 +
 mm/mprotect.c                                 |  14 +-
 tools/arch/x86/include/asm/cpufeatures.h      |   7 +-
 tools/testing/selftests/Makefile              |   1 +
 tools/testing/selftests/sgx/.gitignore        |   2 +
 tools/testing/selftests/sgx/Makefile          |  53 ++
 tools/testing/selftests/sgx/call.S            |  54 ++
 tools/testing/selftests/sgx/defines.h         |  21 +
 tools/testing/selftests/sgx/load.c            | 282 ++++++
 tools/testing/selftests/sgx/main.c            | 199 +++++
 tools/testing/selftests/sgx/main.h            |  38 +
 tools/testing/selftests/sgx/sigstruct.c       | 395 +++++++++
 tools/testing/selftests/sgx/test_encl.c       |  20 +
 tools/testing/selftests/sgx/test_encl.lds     |  40 +
 .../selftests/sgx/test_encl_bootstrap.S       |  89 ++
 52 files changed, 5397 insertions(+), 31 deletions(-)
 create mode 100644 Documentation/x86/sgx.rst
 create mode 100644 arch/x86/entry/vdso/extable.c
 create mode 100644 arch/x86/entry/vdso/extable.h
 create mode 100644 arch/x86/entry/vdso/vsgx_enter_enclave.S
 create mode 100644 arch/x86/include/asm/enclu.h
 create mode 100644 arch/x86/include/uapi/asm/sgx.h
 create mode 100644 arch/x86/kernel/cpu/sgx/Makefile
 create mode 100644 arch/x86/kernel/cpu/sgx/arch.h
 create mode 100644 arch/x86/kernel/cpu/sgx/driver.c
 create mode 100644 arch/x86/kernel/cpu/sgx/driver.h
 create mode 100644 arch/x86/kernel/cpu/sgx/encl.c
 create mode 100644 arch/x86/kernel/cpu/sgx/encl.h
 create mode 100644 arch/x86/kernel/cpu/sgx/encls.h
 create mode 100644 arch/x86/kernel/cpu/sgx/ioctl.c
 create mode 100644 arch/x86/kernel/cpu/sgx/main.c
 create mode 100644 arch/x86/kernel/cpu/sgx/reclaim.c
 create mode 100644 arch/x86/kernel/cpu/sgx/sgx.h
 create mode 100644 tools/testing/selftests/sgx/.gitignore
 create mode 100644 tools/testing/selftests/sgx/Makefile
 create mode 100644 tools/testing/selftests/sgx/call.S
 create mode 100644 tools/testing/selftests/sgx/defines.h
 create mode 100644 tools/testing/selftests/sgx/load.c
 create mode 100644 tools/testing/selftests/sgx/main.c
 create mode 100644 tools/testing/selftests/sgx/main.h
 create mode 100644 tools/testing/selftests/sgx/sigstruct.c
 create mode 100644 tools/testing/selftests/sgx/test_encl.c
 create mode 100644 tools/testing/selftests/sgx/test_encl.lds
 create mode 100644 tools/testing/selftests/sgx/test_encl_bootstrap.S

-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH v30 01/20] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits
  2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
@ 2020-05-15  0:43 ` Jarkko Sakkinen
  2020-05-20 12:16   ` Borislav Petkov
  2020-05-15  0:43 ` [PATCH v30 02/20] x86/cpufeatures: x86/msr: Intel SGX Launch Control " Jarkko Sakkinen
                   ` (19 subsequent siblings)
  20 siblings, 1 reply; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-15  0:43 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: akpm, dave.hansen, sean.j.christopherson, nhorman, npmccallum,
	haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp, josh, luto,
	kai.huang, rientjes, cedric.xing, puiterwijk, Jarkko Sakkinen,
	Jethro Beekman

From: Sean Christopherson <sean.j.christopherson@intel.com>

Add X86_FEATURE_SGX from CPUID.(EAX=7, ECX=1), which informs whether the
CPU has SGX.

Add X86_FEATURE_SGX1 and X86_FEATURE_SGX2 from CPUID.(EAX=12H, ECX=0),
which describe the level of SGX support available [1].

Remap CPUID.(EAX=12H, ECX=0) bits to the Linux fake CPUID 8 in order to
conserve some space. Keep the bit positions intact because KVM requires
this. Reserve bits 0-7 for SGX in order to maintain this invariant also
when new SGX specific feature bits get added.

Add IA32_FEATURE_CONTROL_SGX_ENABLE. BIOS can use this bit to opt-in SGX
before locking the feature control MSR [2].

[1] Intel SDM: 36.7.2 Intel® SGX Resource Enumeration Leaves
[2] Intel SDM: 36.7.1 Intel® SGX Opt-In Configuration

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Co-developed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Acked-by: Jethro Beekman <jethro@fortanix.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 arch/x86/include/asm/cpufeature.h        |  5 +++--
 arch/x86/include/asm/cpufeatures.h       |  7 ++++++-
 arch/x86/include/asm/disabled-features.h | 18 +++++++++++++++---
 arch/x86/include/asm/msr-index.h         |  1 +
 arch/x86/include/asm/required-features.h |  2 +-
 arch/x86/kernel/cpu/common.c             |  4 ++++
 tools/arch/x86/include/asm/cpufeatures.h |  7 ++++++-
 7 files changed, 36 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 59bf91c57aa8..efbdba5170a3 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -30,6 +30,7 @@ enum cpuid_leafs
 	CPUID_7_ECX,
 	CPUID_8000_0007_EBX,
 	CPUID_7_EDX,
+	CPUID_12_EAX,
 };
 
 #ifdef CONFIG_X86_FEATURE_NAMES
@@ -89,7 +90,7 @@ extern const char * const x86_bug_flags[NBUGINTS*32];
 	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 17, feature_bit) ||	\
 	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 18, feature_bit) ||	\
 	   REQUIRED_MASK_CHECK					  ||	\
-	   BUILD_BUG_ON_ZERO(NCAPINTS != 19))
+	   BUILD_BUG_ON_ZERO(NCAPINTS != 20))
 
 #define DISABLED_MASK_BIT_SET(feature_bit)				\
 	 ( CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  0, feature_bit) ||	\
@@ -112,7 +113,7 @@ extern const char * const x86_bug_flags[NBUGINTS*32];
 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 17, feature_bit) ||	\
 	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 18, feature_bit) ||	\
 	   DISABLED_MASK_CHECK					  ||	\
-	   BUILD_BUG_ON_ZERO(NCAPINTS != 19))
+	   BUILD_BUG_ON_ZERO(NCAPINTS != 20))
 
 #define cpu_has(c, bit)							\
 	(__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 :	\
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index db189945e9b0..fc4422f747d5 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -13,7 +13,7 @@
 /*
  * Defines x86 CPU feature bits
  */
-#define NCAPINTS			19	   /* N 32-bit words worth of info */
+#define NCAPINTS			20	   /* N 32-bit words worth of info */
 #define NBUGINTS			1	   /* N 32-bit bug flags */
 
 /*
@@ -238,6 +238,7 @@
 /* Intel-defined CPU features, CPUID level 0x00000007:0 (EBX), word 9 */
 #define X86_FEATURE_FSGSBASE		( 9*32+ 0) /* RDFSBASE, WRFSBASE, RDGSBASE, WRGSBASE instructions*/
 #define X86_FEATURE_TSC_ADJUST		( 9*32+ 1) /* TSC adjustment MSR 0x3B */
+#define X86_FEATURE_SGX			( 9*32+ 2) /* Software Guard Extensions */
 #define X86_FEATURE_BMI1		( 9*32+ 3) /* 1st group bit manipulation extensions */
 #define X86_FEATURE_HLE			( 9*32+ 4) /* Hardware Lock Elision */
 #define X86_FEATURE_AVX2		( 9*32+ 5) /* AVX2 instructions */
@@ -372,6 +373,10 @@
 #define X86_FEATURE_CORE_CAPABILITIES	(18*32+30) /* "" IA32_CORE_CAPABILITIES MSR */
 #define X86_FEATURE_SPEC_CTRL_SSBD	(18*32+31) /* "" Speculative Store Bypass Disable */
 
+/* Intel-defined SGX features, CPUID level 0x00000012:0 (EAX), word 19 */
+#define X86_FEATURE_SGX1		(19*32+ 0) /* SGX1 leaf functions */
+#define X86_FEATURE_SGX2		(19*32+ 1) /* SGX2 leaf functions */
+
 /*
  * BUG word(s)
  */
diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index 4ea8584682f9..dbe534d5153f 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -28,13 +28,18 @@
 # define DISABLE_CYRIX_ARR	(1<<(X86_FEATURE_CYRIX_ARR & 31))
 # define DISABLE_CENTAUR_MCR	(1<<(X86_FEATURE_CENTAUR_MCR & 31))
 # define DISABLE_PCID		0
+# define DISABLE_SGX1		0
+# define DISABLE_SGX2		0
 #else
 # define DISABLE_VME		0
 # define DISABLE_K6_MTRR	0
 # define DISABLE_CYRIX_ARR	0
 # define DISABLE_CENTAUR_MCR	0
 # define DISABLE_PCID		(1<<(X86_FEATURE_PCID & 31))
-#endif /* CONFIG_X86_64 */
+# define DISABLE_SGX1		(1<<(X86_FEATURE_SGX1 & 31))
+# define DISABLE_SGX2		(1<<(X86_FEATURE_SGX2 & 31))
+ #endif /* CONFIG_X86_64 */
+
 
 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
 # define DISABLE_PKU		0
@@ -56,6 +61,12 @@
 # define DISABLE_PTI		(1 << (X86_FEATURE_PTI & 31))
 #endif
 
+#ifdef CONFIG_INTEL_SGX
+# define DISABLE_SGX	0
+#else
+# define DISABLE_SGX	(1 << (X86_FEATURE_SGX & 31))
+#endif
+
 /*
  * Make sure to add features to the correct mask
  */
@@ -68,7 +79,7 @@
 #define DISABLED_MASK6	0
 #define DISABLED_MASK7	(DISABLE_PTI)
 #define DISABLED_MASK8	0
-#define DISABLED_MASK9	(DISABLE_SMAP)
+#define DISABLED_MASK9	(DISABLE_SMAP|DISABLE_SGX)
 #define DISABLED_MASK10	0
 #define DISABLED_MASK11	0
 #define DISABLED_MASK12	0
@@ -78,6 +89,7 @@
 #define DISABLED_MASK16	(DISABLE_PKU|DISABLE_OSPKE|DISABLE_LA57|DISABLE_UMIP)
 #define DISABLED_MASK17	0
 #define DISABLED_MASK18	0
-#define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 19)
+#define DISABLED_MASK19	(DISABLE_SGX1|DISABLE_SGX2)
+#define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 20)
 
 #endif /* _ASM_X86_DISABLED_FEATURES_H */
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 12c9684d59ba..a277d33006c0 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -575,6 +575,7 @@
 #define FEAT_CTL_LOCKED				BIT(0)
 #define FEAT_CTL_VMX_ENABLED_INSIDE_SMX		BIT(1)
 #define FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX	BIT(2)
+#define FEAT_CTL_SGX_ENABLED			BIT(18)
 #define FEAT_CTL_LMCE_ENABLED			BIT(20)
 
 #define MSR_IA32_TSC_ADJUST             0x0000003b
diff --git a/arch/x86/include/asm/required-features.h b/arch/x86/include/asm/required-features.h
index 6847d85400a8..039e58be2fe6 100644
--- a/arch/x86/include/asm/required-features.h
+++ b/arch/x86/include/asm/required-features.h
@@ -101,6 +101,6 @@
 #define REQUIRED_MASK16	0
 #define REQUIRED_MASK17	0
 #define REQUIRED_MASK18	0
-#define REQUIRED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 19)
+#define REQUIRED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 20)
 
 #endif /* _ASM_X86_REQUIRED_FEATURES_H */
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index bed0cb83fe24..f71fb926edb1 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -915,6 +915,10 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
 		c->x86_capability[CPUID_D_1_EAX] = eax;
 	}
 
+	/* Additional Intel-defined SGX flags: level 0x00000012 */
+	if (c->cpuid_level >= 0x00000012)
+		c->x86_capability[CPUID_12_EAX] = cpuid_eax(0x00000012);
+
 	/* AMD-defined flags: level 0x80000001 */
 	eax = cpuid_eax(0x80000000);
 	c->extended_cpuid_level = eax;
diff --git a/tools/arch/x86/include/asm/cpufeatures.h b/tools/arch/x86/include/asm/cpufeatures.h
index db189945e9b0..fc4422f747d5 100644
--- a/tools/arch/x86/include/asm/cpufeatures.h
+++ b/tools/arch/x86/include/asm/cpufeatures.h
@@ -13,7 +13,7 @@
 /*
  * Defines x86 CPU feature bits
  */
-#define NCAPINTS			19	   /* N 32-bit words worth of info */
+#define NCAPINTS			20	   /* N 32-bit words worth of info */
 #define NBUGINTS			1	   /* N 32-bit bug flags */
 
 /*
@@ -238,6 +238,7 @@
 /* Intel-defined CPU features, CPUID level 0x00000007:0 (EBX), word 9 */
 #define X86_FEATURE_FSGSBASE		( 9*32+ 0) /* RDFSBASE, WRFSBASE, RDGSBASE, WRGSBASE instructions*/
 #define X86_FEATURE_TSC_ADJUST		( 9*32+ 1) /* TSC adjustment MSR 0x3B */
+#define X86_FEATURE_SGX			( 9*32+ 2) /* Software Guard Extensions */
 #define X86_FEATURE_BMI1		( 9*32+ 3) /* 1st group bit manipulation extensions */
 #define X86_FEATURE_HLE			( 9*32+ 4) /* Hardware Lock Elision */
 #define X86_FEATURE_AVX2		( 9*32+ 5) /* AVX2 instructions */
@@ -372,6 +373,10 @@
 #define X86_FEATURE_CORE_CAPABILITIES	(18*32+30) /* "" IA32_CORE_CAPABILITIES MSR */
 #define X86_FEATURE_SPEC_CTRL_SSBD	(18*32+31) /* "" Speculative Store Bypass Disable */
 
+/* Intel-defined SGX features, CPUID level 0x00000012:0 (EAX), word 19 */
+#define X86_FEATURE_SGX1		(19*32+ 0) /* SGX1 leaf functions */
+#define X86_FEATURE_SGX2		(19*32+ 1) /* SGX2 leaf functions */
+
 /*
  * BUG word(s)
  */
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH v30 02/20] x86/cpufeatures: x86/msr: Intel SGX Launch Control hardware bits
  2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
  2020-05-15  0:43 ` [PATCH v30 01/20] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
@ 2020-05-15  0:43 ` Jarkko Sakkinen
  2020-05-20 12:23   ` Borislav Petkov
  2020-05-15  0:43 ` [PATCH v30 03/20] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
                   ` (18 subsequent siblings)
  20 siblings, 1 reply; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-15  0:43 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: akpm, dave.hansen, sean.j.christopherson, nhorman, npmccallum,
	haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp, josh, luto,
	kai.huang, rientjes, cedric.xing, puiterwijk, Jarkko Sakkinen,
	Jethro Beekman

From: Sean Christopherson <sean.j.christopherson@intel.com>

Add X86_FEATURE_SGX_LC, which informs whether or not the CPU supports SGX
Launch Control.

Add MSR_IA32_SGXLEPUBKEYHASH{0, 1, 2, 3}, which when combined contain a
SHA256 hash of a 3072-bit RSA public key. SGX backed software packages, so
called enclaves, are always signed. All enclaves signed with the public key
are unconditionally allowed to initialize. [1]

Add FEATURE_CONTROL_SGX_LE_WR bit of the feature control MSR, which informs
whether the formentioned MSRs are writable or not. If the bit is off, the
public key MSRs are read-only for the OS.

If the MSRs are read-only, the platform must provide a launch enclave (LE).
LE can create cryptographic tokens for other enclaves that they can pass
together with their signature to the ENCLS(EINIT) opcode, which is used
to initialize enclaves.

Linux is unlikely to support the locked configuration because it takes away
the control of the launch decisions from the kernel.

[1] Intel SDM: 38.1.4 Intel SGX Launch Control Configuration

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Co-developed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Acked-by: Jethro Beekman <jethro@fortanix.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 arch/x86/include/asm/cpufeatures.h | 1 +
 arch/x86/include/asm/msr-index.h   | 7 +++++++
 2 files changed, 8 insertions(+)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index fc4422f747d5..c2f8962e8468 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -352,6 +352,7 @@
 #define X86_FEATURE_CLDEMOTE		(16*32+25) /* CLDEMOTE instruction */
 #define X86_FEATURE_MOVDIRI		(16*32+27) /* MOVDIRI instruction */
 #define X86_FEATURE_MOVDIR64B		(16*32+28) /* MOVDIR64B instruction */
+#define X86_FEATURE_SGX_LC		(16*32+30) /* Software Guard Extensions Launch Control */
 
 /* AMD-defined CPU features, CPUID level 0x80000007 (EBX), word 17 */
 #define X86_FEATURE_OVERFLOW_RECOV	(17*32+ 0) /* MCA overflow recovery support */
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index a277d33006c0..4b2e9c25cde3 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -575,6 +575,7 @@
 #define FEAT_CTL_LOCKED				BIT(0)
 #define FEAT_CTL_VMX_ENABLED_INSIDE_SMX		BIT(1)
 #define FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX	BIT(2)
+#define FEAT_CTL_SGX_LC_ENABLED			BIT(17)
 #define FEAT_CTL_SGX_ENABLED			BIT(18)
 #define FEAT_CTL_LMCE_ENABLED			BIT(20)
 
@@ -595,6 +596,12 @@
 #define MSR_IA32_UCODE_WRITE		0x00000079
 #define MSR_IA32_UCODE_REV		0x0000008b
 
+/* Intel SGX Launch Enclave Public Key Hash MSRs */
+#define MSR_IA32_SGXLEPUBKEYHASH0	0x0000008C
+#define MSR_IA32_SGXLEPUBKEYHASH1	0x0000008D
+#define MSR_IA32_SGXLEPUBKEYHASH2	0x0000008E
+#define MSR_IA32_SGXLEPUBKEYHASH3	0x0000008F
+
 #define MSR_IA32_SMM_MONITOR_CTL	0x0000009b
 #define MSR_IA32_SMBASE			0x0000009e
 
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH v30 03/20] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX
  2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
  2020-05-15  0:43 ` [PATCH v30 01/20] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
  2020-05-15  0:43 ` [PATCH v30 02/20] x86/cpufeatures: x86/msr: Intel SGX Launch Control " Jarkko Sakkinen
@ 2020-05-15  0:43 ` Jarkko Sakkinen
  2020-05-15  0:43 ` [PATCH v30 04/20] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
                   ` (17 subsequent siblings)
  20 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-15  0:43 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: akpm, dave.hansen, sean.j.christopherson, nhorman, npmccallum,
	haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp, josh, luto,
	kai.huang, rientjes, cedric.xing, puiterwijk, Jethro Beekman,
	Jarkko Sakkinen

From: Sean Christopherson <sean.j.christopherson@intel.com>

Include SGX bit to the PF error codes and throw SIGSEGV with PF_SGX when
a #PF with SGX set happens.

CPU throws a #PF with the SGX bit in the event of Enclave Page Cache Map
(EPCM) conflict. The EPCM is a CPU-internal table, which describes the
properties for a enclave page. Enclaves are measured and signed software
entities, which SGX hosts. [1]

Although the primary purpose of the EPCM conflict checks  is to prevent
malicious accesses to an enclave, an illegit access can happen also for
legit reasons.

All SGX reserved memory, including EPCM is encrypted with a transient
key that does not survive from the power transition. Throwing a SIGSEGV
allows user space software react when this happens (e.g. rec-create the
enclave, which was invalidated).

[1] Intel SDM: 36.5.1 Enclave Page Cache Map (EPCM)

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Jethro Beekman <jethro@fortanix.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 arch/x86/include/asm/traps.h |  1 +
 arch/x86/mm/fault.c          | 13 +++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
index c26a7e1d8a2c..07dd9f74d65a 100644
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -171,5 +171,6 @@ enum x86_pf_error_code {
 	X86_PF_RSVD	=		1 << 3,
 	X86_PF_INSTR	=		1 << 4,
 	X86_PF_PK	=		1 << 5,
+	X86_PF_SGX	=		1 << 15,
 };
 #endif /* _ASM_X86_TRAPS_H */
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index a51df516b87b..16c53c874bb9 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1201,6 +1201,19 @@ access_error(unsigned long error_code, struct vm_area_struct *vma)
 	if (error_code & X86_PF_PK)
 		return 1;
 
+	/*
+	 * Access is blocked by the Enclave Page Cache Map (EPCM), i.e. the
+	 * access is allowed by the PTE but not the EPCM. This usually happens
+	 * when the EPCM is yanked out from under us, e.g. by hardware after a
+	 * suspend/resume cycle. In any case, software, i.e. the kernel, can't
+	 * fix the source of the fault as the EPCM can't be directly modified by
+	 * software. Handle the fault as an access error in order to signal
+	 * userspace so that userspace can rebuild their enclave(s), even though
+	 * userspace may not have actually violated access permissions.
+	 */
+	if (unlikely(error_code & X86_PF_SGX))
+		return 1;
+
 	/*
 	 * Make sure to check the VMA so that we do not perform
 	 * faults just to hit a X86_PF_PK as soon as we fill in a
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH v30 04/20] x86/sgx: Add SGX microarchitectural data structures
  2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
                   ` (2 preceding siblings ...)
  2020-05-15  0:43 ` [PATCH v30 03/20] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
@ 2020-05-15  0:43 ` Jarkko Sakkinen
  2020-05-20 18:47   ` Borislav Petkov
  2020-05-15  0:43 ` [PATCH v30 05/20] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
                   ` (16 subsequent siblings)
  20 siblings, 1 reply; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-15  0:43 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: akpm, dave.hansen, sean.j.christopherson, nhorman, npmccallum,
	haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp, josh, luto,
	kai.huang, rientjes, cedric.xing, puiterwijk, Jarkko Sakkinen,
	Jethro Beekman

Define the SGX microarchitectural data structures used by various SGX
opcodes. This is not an exhaustive representation of all SGX data
structures but only those needed by the kernel.

The data structures are described in:

  Intel SDM: 37.6 INTEL® SGX DATA STRUCTURES OVERVIEW

Acked-by: Jethro Beekman <jethro@fortanix.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 arch/x86/kernel/cpu/sgx/arch.h | 343 +++++++++++++++++++++++++++++++++
 1 file changed, 343 insertions(+)
 create mode 100644 arch/x86/kernel/cpu/sgx/arch.h

diff --git a/arch/x86/kernel/cpu/sgx/arch.h b/arch/x86/kernel/cpu/sgx/arch.h
new file mode 100644
index 000000000000..ddae55e9d4d8
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/arch.h
@@ -0,0 +1,343 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
+/**
+ * Copyright(c) 2016-18 Intel Corporation.
+ *
+ * Contains data structures defined by the SGX architecture.  Data structures
+ * defined by the Linux software stack should not be placed here.
+ */
+#ifndef _ASM_X86_SGX_ARCH_H
+#define _ASM_X86_SGX_ARCH_H
+
+#include <linux/bits.h>
+#include <linux/types.h>
+
+#define SGX_CPUID				0x12
+#define SGX_CPUID_FIRST_VARIABLE_SUB_LEAF	2
+
+/**
+ * enum sgx_return_code - The return code type for ENCLS, ENCLU and ENCLV
+ * %SGX_NOT_TRACKED:		Previous ETRACK's shootdown sequence has not
+ *				been completed yet.
+ * %SGX_INVALID_EINITTOKEN:	EINITTOKEN is invalid and enclave signer's
+ *				public key does not match IA32_SGXLEPUBKEYHASH.
+ * %SGX_UNMASKED_EVENT:		An unmasked event, e.g. INTR, was received
+ */
+enum sgx_return_code {
+	SGX_NOT_TRACKED			= 11,
+	SGX_INVALID_EINITTOKEN		= 16,
+	SGX_UNMASKED_EVENT		= 128,
+};
+
+/**
+ * enum sgx_sub_leaf_types - SGX CPUID variable sub-leaf types
+ * %SGX_CPUID_SUB_LEAF_INVALID:		Indicates this sub-leaf is invalid.
+ * %SGX_CPUID_SUB_LEAF_EPC_SECTION:	Sub-leaf enumerates an EPC section.
+ */
+enum sgx_sub_leaf_types {
+	SGX_CPUID_SUB_LEAF_INVALID	= 0x0,
+	SGX_CPUID_SUB_LEAF_EPC_SECTION	= 0x1,
+};
+
+#define SGX_CPUID_SUB_LEAF_TYPE_MASK	GENMASK(3, 0)
+
+#define SGX_MODULUS_SIZE 384
+
+/**
+ * enum sgx_miscselect - additional information to an SSA frame
+ * %SGX_MISC_EXINFO:	Report #PF or #GP to the SSA frame.
+ *
+ * Save State Area (SSA) is a stack inside the enclave used to store processor
+ * state when an exception or interrupt occurs. This enum defines additional
+ * information stored to an SSA frame.
+ */
+enum sgx_miscselect {
+	SGX_MISC_EXINFO		= BIT(0),
+};
+
+#define SGX_MISC_RESERVED_MASK	GENMASK_ULL(63, 1)
+
+#define SGX_SSA_GPRS_SIZE		184
+#define SGX_SSA_MISC_EXINFO_SIZE	16
+
+/**
+ * enum sgx_attributes - the attributes field in &struct sgx_secs
+ * %SGX_ATTR_INIT:		Enclave can be entered (is initialized).
+ * %SGX_ATTR_DEBUG:		Allow ENCLS(EDBGRD) and ENCLS(EDBGWR).
+ * %SGX_ATTR_MODE64BIT:		Tell that this a 64-bit enclave.
+ * %SGX_ATTR_PROVISIONKEY:      Allow to use provisioning keys for remote
+ *				attestation.
+ * %SGX_ATTR_KSS:		Allow to use key separation and sharing (KSS).
+ * %SGX_ATTR_EINITTOKENKEY:	Allow to use token signing key that is used to
+ *				sign cryptographic tokens that can be passed to
+ *				EINIT as an authorization to run an enclave.
+ */
+enum sgx_attribute {
+	SGX_ATTR_INIT		= BIT(0),
+	SGX_ATTR_DEBUG		= BIT(1),
+	SGX_ATTR_MODE64BIT	= BIT(2),
+	SGX_ATTR_PROVISIONKEY	= BIT(4),
+	SGX_ATTR_EINITTOKENKEY	= BIT(5),
+	SGX_ATTR_KSS		= BIT(7),
+};
+
+#define SGX_ATTR_RESERVED_MASK	(BIT_ULL(3) | BIT_ULL(6) | GENMASK_ULL(63, 8))
+#define SGX_ATTR_ALLOWED_MASK	(SGX_ATTR_DEBUG | SGX_ATTR_MODE64BIT | \
+				 SGX_ATTR_KSS)
+
+/**
+ * struct sgx_secs - SGX Enclave Control Structure (SECS)
+ * @size:		size of the address space
+ * @base:		base address of the  address space
+ * @ssa_frame_size:	size of an SSA frame
+ * @miscselect:		additional information stored to an SSA frame
+ * @attributes:		attributes for enclave
+ * @xfrm:		XSave-Feature Request Mask (subset of XCR0)
+ * @mrenclave:		SHA256-hash of the enclave contents
+ * @mrsigner:		SHA256-hash of the public key used to sign the SIGSTRUCT
+ * @config_id:		a user-defined value that is used in key derivation
+ * @isv_prod_id:	a user-defined value that is used in key derivation
+ * @isv_svn:		a user-defined value that is used in key derivation
+ * @config_svn:		a user-defined value that is used in key derivation
+ *
+ * SGX Enclave Control Structure (SECS) is a special enclave page that is not
+ * visible in the address space. In fact, this structure defines the address
+ * range and other global attributes for the enclave and it is the first EPC
+ * page created for any enclave. It is moved from a temporary buffer to an EPC
+ * by the means of ENCLS(ECREATE) leaf.
+ */
+struct sgx_secs {
+	u64 size;
+	u64 base;
+	u32 ssa_frame_size;
+	u32 miscselect;
+	u8  reserved1[24];
+	u64 attributes;
+	u64 xfrm;
+	u32 mrenclave[8];
+	u8  reserved2[32];
+	u32 mrsigner[8];
+	u8  reserved3[32];
+	u32 config_id[16];
+	u16 isv_prod_id;
+	u16 isv_svn;
+	u16 config_svn;
+	u8  reserved4[3834];
+} __packed;
+
+/**
+ * enum sgx_tcs_flags - execution flags for TCS
+ * %SGX_TCS_DBGOPTIN:	If enabled allows single-stepping and breakpoints
+ *			inside an enclave. It is cleared by EADD but can
+ *			be set later with EDBGWR.
+ */
+enum sgx_tcs_flags {
+	SGX_TCS_DBGOPTIN	= 0x01,
+};
+
+#define SGX_TCS_RESERVED_MASK	GENMASK_ULL(63, 1)
+#define SGX_TCS_RESERVED_SIZE	4024
+
+/**
+ * struct sgx_tcs - Thread Control Structure (TCS)
+ * @state:		used to mark an entered TCS
+ * @flags:		execution flags (cleared by EADD)
+ * @ssa_offset:		SSA stack offset relative to the enclave base
+ * @ssa_index:		the current SSA frame index (cleard by EADD)
+ * @nr_ssa_frames:	the number of frame in the SSA stack
+ * @entry_offset:	entry point offset relative to the enclave base
+ * @exit_addr:		address outside the enclave to exit on an exception or
+ *			interrupt
+ * @fs_offset:		offset relative to the enclave base to become FS
+ *			segment inside the enclave
+ * @gs_offset:		offset relative to the enclave base to become GS
+ *			segment inside the enclave
+ * @fs_limit:		size to become a new FS-limit (only 32-bit enclaves)
+ * @gs_limit:		size to become a new GS-limit (only 32-bit enclaves)
+ *
+ * Thread Control Structure (TCS) is an enclave page visible in its address
+ * space that defines an entry point inside the enclave. A thread enters inside
+ * an enclave by supplying address of TCS to ENCLU(EENTER). A TCS can be entered
+ * by only one thread at a time.
+ */
+struct sgx_tcs {
+	u64 state;
+	u64 flags;
+	u64 ssa_offset;
+	u32 ssa_index;
+	u32 nr_ssa_frames;
+	u64 entry_offset;
+	u64 exit_addr;
+	u64 fs_offset;
+	u64 gs_offset;
+	u32 fs_limit;
+	u32 gs_limit;
+	u8  reserved[SGX_TCS_RESERVED_SIZE];
+} __packed;
+
+/**
+ * struct sgx_pageinfo - an enclave page descriptor
+ * @addr:	address of the enclave page
+ * @contents:	pointer to the page contents
+ * @metadata:	pointer either to a SECINFO or PCMD instance
+ * @secs:	address of the SECS page
+ */
+struct sgx_pageinfo {
+	u64 addr;
+	u64 contents;
+	u64 metadata;
+	u64 secs;
+} __packed __aligned(32);
+
+
+/**
+ * enum sgx_page_type - bits in the SECINFO flags defining the page type
+ * %SGX_PAGE_TYPE_SECS:	a SECS page
+ * %SGX_PAGE_TYPE_TCS:	a TCS page
+ * %SGX_PAGE_TYPE_REG:	a regular page
+ * %SGX_PAGE_TYPE_VA:	a VA page
+ * %SGX_PAGE_TYPE_TRIM:	a page in trimmed state
+ */
+enum sgx_page_type {
+	SGX_PAGE_TYPE_SECS,
+	SGX_PAGE_TYPE_TCS,
+	SGX_PAGE_TYPE_REG,
+	SGX_PAGE_TYPE_VA,
+	SGX_PAGE_TYPE_TRIM,
+};
+
+#define SGX_NR_PAGE_TYPES	5
+#define SGX_PAGE_TYPE_MASK	GENMASK(7, 0)
+
+/**
+ * enum sgx_secinfo_flags - the flags field in &struct sgx_secinfo
+ * %SGX_SECINFO_R:	allow read
+ * %SGX_SECINFO_W:	allow write
+ * %SGX_SECINFO_X:	allow execution
+ * %SGX_SECINFO_SECS:	a SECS page
+ * %SGX_SECINFO_TCS:	a TCS page
+ * %SGX_SECINFO_REG:	a regular page
+ * %SGX_SECINFO_VA:	a VA page
+ * %SGX_SECINFO_TRIM:	a page in trimmed state
+ */
+enum sgx_secinfo_flags {
+	SGX_SECINFO_R			= BIT(0),
+	SGX_SECINFO_W			= BIT(1),
+	SGX_SECINFO_X			= BIT(2),
+	SGX_SECINFO_SECS		= (SGX_PAGE_TYPE_SECS << 8),
+	SGX_SECINFO_TCS			= (SGX_PAGE_TYPE_TCS << 8),
+	SGX_SECINFO_REG			= (SGX_PAGE_TYPE_REG << 8),
+	SGX_SECINFO_VA			= (SGX_PAGE_TYPE_VA << 8),
+	SGX_SECINFO_TRIM		= (SGX_PAGE_TYPE_TRIM << 8),
+};
+
+#define SGX_SECINFO_PERMISSION_MASK	GENMASK_ULL(2, 0)
+#define SGX_SECINFO_PAGE_TYPE_MASK	(SGX_PAGE_TYPE_MASK << 8)
+#define SGX_SECINFO_RESERVED_MASK	~(SGX_SECINFO_PERMISSION_MASK | \
+					  SGX_SECINFO_PAGE_TYPE_MASK)
+
+/**
+ * struct sgx_secinfo - describes attributes of an EPC page
+ * @flags:	permissions and type
+ *
+ * Used together with ENCLS leaves that add or modify an EPC page to an
+ * enclave to define page permissions and type.
+ */
+struct sgx_secinfo {
+	u64 flags;
+	u8  reserved[56];
+} __packed __aligned(64);
+
+#define SGX_PCMD_RESERVED_SIZE 40
+
+/**
+ * struct sgx_pcmd - Paging Crypto Metadata (PCMD)
+ * @enclave_id:	enclave identifier
+ * @mac:	MAC over PCMD, page contents and isvsvn
+ *
+ * PCMD is stored for every swapped page to the regular memory. When ELDU loads
+ * the page back it recalculates the MAC by using a isvsvn number stored in a
+ * VA page. Together these two structures bring integrity and rollback
+ * protection.
+ */
+struct sgx_pcmd {
+	struct sgx_secinfo secinfo;
+	u64 enclave_id;
+	u8  reserved[SGX_PCMD_RESERVED_SIZE];
+	u8  mac[16];
+} __packed __aligned(128);
+
+#define SGX_SIGSTRUCT_RESERVED1_SIZE 84
+#define SGX_SIGSTRUCT_RESERVED2_SIZE 20
+#define SGX_SIGSTRUCT_RESERVED3_SIZE 32
+#define SGX_SIGSTRUCT_RESERVED4_SIZE 12
+
+/**
+ * struct sgx_sigstruct_header -  defines author of the enclave
+ * @header1:		constant byte string
+ * @vendor:		must be either 0x0000 or 0x8086
+ * @date:		YYYYMMDD in BCD
+ * @header2:		costant byte string
+ * @swdefined:		software defined value
+ */
+struct sgx_sigstruct_header {
+	u64 header1[2];
+	u32 vendor;
+	u32 date;
+	u64 header2[2];
+	u32 swdefined;
+	u8  reserved1[84];
+} __packed;
+
+/**
+ * struct sgx_sigstruct_body - defines contents of the enclave
+ * @miscselect:		additional information stored to an SSA frame
+ * @misc_mask:		required miscselect in SECS
+ * @attributes:		attributes for enclave
+ * @xfrm:		XSave-Feature Request Mask (subset of XCR0)
+ * @attributes_mask:	required attributes in SECS
+ * @xfrm_mask:		required XFRM in SECS
+ * @mrenclave:		SHA256-hash of the enclave contents
+ * @isvprodid:		a user-defined value that is used in key derivation
+ * @isvsvn:		a user-defined value that is used in key derivation
+ */
+struct sgx_sigstruct_body {
+	u32 miscselect;
+	u32 misc_mask;
+	u8  reserved2[20];
+	u64 attributes;
+	u64 xfrm;
+	u64 attributes_mask;
+	u64 xfrm_mask;
+	u8  mrenclave[32];
+	u8  reserved3[32];
+	u16 isvprodid;
+	u16 isvsvn;
+} __packed;
+
+/**
+ * struct sgx_sigstruct - an enclave signature
+ * @header:		defines author of the enclave
+ * @modulus:		the modulus of the public key
+ * @exponent:		the exponent of the public key
+ * @signature:		the signature calculated over the fields except modulus,
+ * @body:		defines contents of the enclave
+ * @q1:			a value used in RSA signature verification
+ * @q2:			a value used in RSA signature verification
+ *
+ * Header and body are the parts that are actual signed. The remaining fields
+ * define the signature of the enclave.
+ */
+struct sgx_sigstruct {
+	struct sgx_sigstruct_header header;
+	u8  modulus[SGX_MODULUS_SIZE];
+	u32 exponent;
+	u8  signature[SGX_MODULUS_SIZE];
+	struct sgx_sigstruct_body body;
+	u8  reserved4[12];
+	u8  q1[SGX_MODULUS_SIZE];
+	u8  q2[SGX_MODULUS_SIZE];
+} __packed;
+
+#define SGX_LAUNCH_TOKEN_SIZE 304
+
+#endif /* _ASM_X86_SGX_ARCH_H */
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH v30 05/20] x86/sgx: Add wrappers for ENCLS leaf functions
  2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
                   ` (3 preceding siblings ...)
  2020-05-15  0:43 ` [PATCH v30 04/20] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
@ 2020-05-15  0:43 ` Jarkko Sakkinen
  2020-05-15  0:43 ` [PATCH v30 06/20] x86/cpu/intel: Detect SGX support Jarkko Sakkinen
                   ` (15 subsequent siblings)
  20 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-15  0:43 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: akpm, dave.hansen, sean.j.christopherson, nhorman, npmccallum,
	haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp, josh, luto,
	kai.huang, rientjes, cedric.xing, puiterwijk, Jarkko Sakkinen,
	Jethro Beekman

ENCLS is a ring 0 instruction, which contains a set of leaf functions for
managing an enclave. Enclaves are measured and signed software entities,
which are protected by asserting the outside memory accesses and memory
encryption.

Add a two-layer macro system along with an encoding scheme to allow
wrappers to return trap numbers along ENCLS-specific error codes. The
bottom layer of the macro system splits between the leafs that return an
error code and those that do not. The second layer generates the correct
input/output annotations based on the number of operands for each leaf
function.

ENCLS leaf functions are documented in

  Intel SDM: 36.6 ENCLAVE INSTRUCTIONS AND INTEL®

Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Jethro Beekman <jethro@fortanix.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 arch/x86/kernel/cpu/sgx/encls.h | 239 ++++++++++++++++++++++++++++++++
 1 file changed, 239 insertions(+)
 create mode 100644 arch/x86/kernel/cpu/sgx/encls.h

diff --git a/arch/x86/kernel/cpu/sgx/encls.h b/arch/x86/kernel/cpu/sgx/encls.h
new file mode 100644
index 000000000000..376cdedb9a43
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/encls.h
@@ -0,0 +1,239 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
+#ifndef _X86_ENCLS_H
+#define _X86_ENCLS_H
+
+#include <linux/bitops.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/rwsem.h>
+#include <linux/types.h>
+#include <asm/asm.h>
+#include <asm/traps.h>
+#include "sgx.h"
+
+enum sgx_encls_leaf {
+	ECREATE	= 0x00,
+	EADD	= 0x01,
+	EINIT	= 0x02,
+	EREMOVE	= 0x03,
+	EDGBRD	= 0x04,
+	EDGBWR	= 0x05,
+	EEXTEND	= 0x06,
+	ELDU	= 0x08,
+	EBLOCK	= 0x09,
+	EPA	= 0x0A,
+	EWB	= 0x0B,
+	ETRACK	= 0x0C,
+};
+
+/**
+ * ENCLS_FAULT_FLAG - flag signifying an ENCLS return code is a trapnr
+ *
+ * ENCLS has its own (positive value) error codes and also generates
+ * ENCLS specific #GP and #PF faults.  And the ENCLS values get munged
+ * with system error codes as everything percolates back up the stack.
+ * Unfortunately (for us), we need to precisely identify each unique
+ * error code, e.g. the action taken if EWB fails varies based on the
+ * type of fault and on the exact SGX error code, i.e. we can't simply
+ * convert all faults to -EFAULT.
+ *
+ * To make all three error types coexist, we set bit 30 to identify an
+ * ENCLS fault.  Bit 31 (technically bits N:31) is used to differentiate
+ * between positive (faults and SGX error codes) and negative (system
+ * error codes) values.
+ */
+#define ENCLS_FAULT_FLAG 0x40000000
+
+/* Retrieve the encoded trapnr from the specified return code. */
+#define ENCLS_TRAPNR(r) ((r) & ~ENCLS_FAULT_FLAG)
+
+/* Issue a WARN() about an ENCLS leaf. */
+#define ENCLS_WARN(r, name) {						  \
+	do {								  \
+		int _r = (r);						  \
+		WARN_ONCE(_r, "%s returned %d (0x%x)\n", (name), _r, _r); \
+	} while (0);							  \
+}
+
+/**
+ * encls_failed() - Check if an ENCLS leaf function failed
+ * @ret:	the return value of an ENCLS leaf function call
+ *
+ * Check if an ENCLS leaf function failed. This happens when the leaf function
+ * causes a fault that is not caused by an EPCM conflict or when the leaf
+ * function returns a non-zero value.
+ */
+static inline bool encls_failed(int ret)
+{
+	int epcm_trapnr;
+
+	if (boot_cpu_has(X86_FEATURE_SGX2))
+		epcm_trapnr = X86_TRAP_PF;
+	else
+		epcm_trapnr = X86_TRAP_GP;
+
+	if (ret & ENCLS_FAULT_FLAG)
+		return ENCLS_TRAPNR(ret) != epcm_trapnr;
+
+	return !!ret;
+}
+
+/**
+ * __encls_ret_N - encode an ENCLS leaf that returns an error code in EAX
+ * @rax:	leaf number
+ * @inputs:	asm inputs for the leaf
+ *
+ * Emit assembly for an ENCLS leaf that returns an error code, e.g. EREMOVE.
+ * And because SGX isn't complex enough as it is, leafs that return an error
+ * code also modify flags.
+ *
+ * Return:
+ *	0 on success,
+ *	SGX error code on failure
+ */
+#define __encls_ret_N(rax, inputs...)				\
+	({							\
+	int ret;						\
+	asm volatile(						\
+	"1: .byte 0x0f, 0x01, 0xcf;\n\t"			\
+	"2:\n"							\
+	".section .fixup,\"ax\"\n"				\
+	"3: orl $"__stringify(ENCLS_FAULT_FLAG)",%%eax\n"	\
+	"   jmp 2b\n"						\
+	".previous\n"						\
+	_ASM_EXTABLE_FAULT(1b, 3b)				\
+	: "=a"(ret)						\
+	: "a"(rax), inputs					\
+	: "memory", "cc");					\
+	ret;							\
+	})
+
+#define __encls_ret_1(rax, rcx)		\
+	({				\
+	__encls_ret_N(rax, "c"(rcx));	\
+	})
+
+#define __encls_ret_2(rax, rbx, rcx)		\
+	({					\
+	__encls_ret_N(rax, "b"(rbx), "c"(rcx));	\
+	})
+
+#define __encls_ret_3(rax, rbx, rcx, rdx)			\
+	({							\
+	__encls_ret_N(rax, "b"(rbx), "c"(rcx), "d"(rdx));	\
+	})
+
+/**
+ * __encls_N - encode an ENCLS leaf that doesn't return an error code
+ * @rax:	leaf number
+ * @rbx_out:	optional output variable
+ * @inputs:	asm inputs for the leaf
+ *
+ * Emit assembly for an ENCLS leaf that does not return an error code,
+ * e.g. ECREATE.  Leaves without error codes either succeed or fault.
+ * @rbx_out is an optional parameter for use by EDGBRD, which returns
+ * the the requested value in RBX.
+ *
+ * Return:
+ *   0 on success,
+ *   trapnr with ENCLS_FAULT_FLAG set on fault
+ */
+#define __encls_N(rax, rbx_out, inputs...)			\
+	({							\
+	int ret;						\
+	asm volatile(						\
+	"1: .byte 0x0f, 0x01, 0xcf;\n\t"			\
+	"   xor %%eax,%%eax;\n"					\
+	"2:\n"							\
+	".section .fixup,\"ax\"\n"				\
+	"3: orl $"__stringify(ENCLS_FAULT_FLAG)",%%eax\n"	\
+	"   jmp 2b\n"						\
+	".previous\n"						\
+	_ASM_EXTABLE_FAULT(1b, 3b)				\
+	: "=a"(ret), "=b"(rbx_out)				\
+	: "a"(rax), inputs					\
+	: "memory");						\
+	ret;							\
+	})
+
+#define __encls_2(rax, rbx, rcx)				\
+	({							\
+	unsigned long ign_rbx_out;				\
+	__encls_N(rax, ign_rbx_out, "b"(rbx), "c"(rcx));	\
+	})
+
+#define __encls_1_1(rax, data, rcx)			\
+	({						\
+	unsigned long rbx_out;				\
+	int ret = __encls_N(rax, rbx_out, "c"(rcx));	\
+	if (!ret)					\
+		data = rbx_out;				\
+	ret;						\
+	})
+
+static inline int __ecreate(struct sgx_pageinfo *pginfo, void *secs)
+{
+	return __encls_2(ECREATE, pginfo, secs);
+}
+
+static inline int __eextend(void *secs, void *addr)
+{
+	return __encls_2(EEXTEND, secs, addr);
+}
+
+static inline int __eadd(struct sgx_pageinfo *pginfo, void *addr)
+{
+	return __encls_2(EADD, pginfo, addr);
+}
+
+static inline int __einit(void *sigstruct, struct sgx_einittoken *einittoken,
+			  void *secs)
+{
+	return __encls_ret_3(EINIT, sigstruct, secs, einittoken);
+}
+
+static inline int __eremove(void *addr)
+{
+	return __encls_ret_1(EREMOVE, addr);
+}
+
+static inline int __edbgwr(void *addr, unsigned long *data)
+{
+	return __encls_2(EDGBWR, *data, addr);
+}
+
+static inline int __edbgrd(void *addr, unsigned long *data)
+{
+	return __encls_1_1(EDGBRD, *data, addr);
+}
+
+static inline int __etrack(void *addr)
+{
+	return __encls_ret_1(ETRACK, addr);
+}
+
+static inline int __eldu(struct sgx_pageinfo *pginfo, void *addr,
+			 void *va)
+{
+	return __encls_ret_3(ELDU, pginfo, addr, va);
+}
+
+static inline int __eblock(void *addr)
+{
+	return __encls_ret_1(EBLOCK, addr);
+}
+
+static inline int __epa(void *addr)
+{
+	unsigned long rbx = SGX_PAGE_TYPE_VA;
+
+	return __encls_2(EPA, rbx, addr);
+}
+
+static inline int __ewb(struct sgx_pageinfo *pginfo, void *addr,
+			void *va)
+{
+	return __encls_ret_3(EWB, pginfo, addr, va);
+}
+
+#endif /* _X86_ENCLS_H */
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH v30 06/20] x86/cpu/intel: Detect SGX support
  2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
                   ` (4 preceding siblings ...)
  2020-05-15  0:43 ` [PATCH v30 05/20] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
@ 2020-05-15  0:43 ` Jarkko Sakkinen
  2020-05-15  0:43 ` [PATCH v30 07/20] x86/sgx: Enumerate and track EPC sections Jarkko Sakkinen
                   ` (14 subsequent siblings)
  20 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-15  0:43 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: akpm, dave.hansen, sean.j.christopherson, nhorman, npmccallum,
	haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp, josh, luto,
	kai.huang, rientjes, cedric.xing, puiterwijk, Jarkko Sakkinen,
	Jethro Beekman

From: Sean Christopherson <sean.j.christopherson@intel.com>

Configure SGX as part of feature control MSR initialization and update
the associated X86_FEATURE flags accordingly.  Because the kernel will
require the LE hash MSRs to be writable when running native enclaves,
disable X86_FEATURE_SGX (and all derivatives) if SGX Launch Control is
not (or cannot) be fully enabled via feature control MSR.

The check is done for every CPU, not just BSP, in order to verify that
MSR_IA32_FEATURE_CONTROL is correctly configured on all CPUs. The other
parts of the kernel, like the enclave driver, expect the same
configuration from all CPUs.

Note, unlike VMX, clear the X86_FEATURE_SGX* flags for all CPUs if any
CPU lacks SGX support as the kernel expects SGX to be available on all
CPUs.  X86_FEATURE_VMX is intentionally cleared only for the current CPU
so that KVM can provide additional information if KVM fails to load,
e.g. print which CPU doesn't support VMX.  KVM/VMX requires additional
per-CPU enabling, e.g. to set CR4.VMXE and do VMXON, and so already has
the necessary infrastructure to do per-CPU checks.  SGX on the other
hand doesn't require additional enabling, so clearing the feature flags
on all CPUs means the SGX subsystem doesn't need to manually do support
checks on a per-CPU basis.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Co-developed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Acked-by: Jethro Beekman <jethro@fortanix.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 arch/x86/kernel/cpu/feat_ctl.c | 32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/feat_ctl.c b/arch/x86/kernel/cpu/feat_ctl.c
index 29a3bedabd06..c3afcd2e4342 100644
--- a/arch/x86/kernel/cpu/feat_ctl.c
+++ b/arch/x86/kernel/cpu/feat_ctl.c
@@ -93,16 +93,35 @@ static void init_vmx_capabilities(struct cpuinfo_x86 *c)
 }
 #endif /* CONFIG_X86_VMX_FEATURE_NAMES */
 
+static void clear_sgx_caps(void)
+{
+	setup_clear_cpu_cap(X86_FEATURE_SGX);
+	setup_clear_cpu_cap(X86_FEATURE_SGX_LC);
+	setup_clear_cpu_cap(X86_FEATURE_SGX1);
+	setup_clear_cpu_cap(X86_FEATURE_SGX2);
+}
+
 void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
 {
 	bool tboot = tboot_enabled();
+	bool enable_sgx;
 	u64 msr;
 
 	if (rdmsrl_safe(MSR_IA32_FEAT_CTL, &msr)) {
 		clear_cpu_cap(c, X86_FEATURE_VMX);
+		clear_sgx_caps();
 		return;
 	}
 
+	/*
+	 * Enable SGX if and only if the kernel supports SGX and Launch Control
+	 * is supported, i.e. disable SGX if the LE hash MSRs can't be written.
+	 */
+	enable_sgx = cpu_has(c, X86_FEATURE_SGX) &&
+		     cpu_has(c, X86_FEATURE_SGX1) &&
+		     cpu_has(c, X86_FEATURE_SGX_LC) &&
+		     IS_ENABLED(CONFIG_INTEL_SGX);
+
 	if (msr & FEAT_CTL_LOCKED)
 		goto update_caps;
 
@@ -124,13 +143,16 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
 			msr |= FEAT_CTL_VMX_ENABLED_INSIDE_SMX;
 	}
 
+	if (enable_sgx)
+		msr |= FEAT_CTL_SGX_ENABLED | FEAT_CTL_SGX_LC_ENABLED;
+
 	wrmsrl(MSR_IA32_FEAT_CTL, msr);
 
 update_caps:
 	set_cpu_cap(c, X86_FEATURE_MSR_IA32_FEAT_CTL);
 
 	if (!cpu_has(c, X86_FEATURE_VMX))
-		return;
+		goto update_sgx;
 
 	if ( (tboot && !(msr & FEAT_CTL_VMX_ENABLED_INSIDE_SMX)) ||
 	    (!tboot && !(msr & FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX))) {
@@ -143,4 +165,12 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
 		init_vmx_capabilities(c);
 #endif
 	}
+
+update_sgx:
+	if (!(msr & FEAT_CTL_SGX_ENABLED) ||
+	    !(msr & FEAT_CTL_SGX_LC_ENABLED) || !enable_sgx) {
+		if (enable_sgx)
+			pr_err_once("SGX disabled by BIOS\n");
+		clear_sgx_caps();
+	}
 }
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH v30 07/20] x86/sgx: Enumerate and track EPC sections
  2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
                   ` (5 preceding siblings ...)
  2020-05-15  0:43 ` [PATCH v30 06/20] x86/cpu/intel: Detect SGX support Jarkko Sakkinen
@ 2020-05-15  0:43 ` Jarkko Sakkinen
  2020-05-25  9:23   ` Borislav Petkov
  2020-05-15  0:43 ` [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages Jarkko Sakkinen
                   ` (13 subsequent siblings)
  20 siblings, 1 reply; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-15  0:43 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: akpm, dave.hansen, sean.j.christopherson, nhorman, npmccallum,
	haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp, josh, luto,
	kai.huang, rientjes, cedric.xing, puiterwijk, Serge Ayoun,
	Jarkko Sakkinen, Jethro Beekman

From: Sean Christopherson <sean.j.christopherson@intel.com>

Enumerate Enclave Page Cache (EPC) sections via CPUID and add the data
structures necessary to track EPC pages so that they can be allocated,
freed and managed. As a system may have multiple EPC sections, invoke CPUID
on SGX sub-leafs until an invalid leaf is encountered.

For simplicity, support a maximum of eight EPC sections. Existing client
hardware supports only a single section, while upcoming server hardware
will support at most eight sections. Bounding the number of sections also
allows the section ID to be embedded along with a page's offset in a single
unsigned long, enabling easy retrieval of both the VA and PA for a given
page.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Co-developed-by: Serge Ayoun <serge.ayoun@intel.com>
Signed-off-by: Serge Ayoun <serge.ayoun@intel.com>
Co-developed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Acked-by: Jethro Beekman <jethro@fortanix.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 arch/x86/Kconfig                  |  14 +++
 arch/x86/kernel/cpu/Makefile      |   1 +
 arch/x86/kernel/cpu/sgx/Makefile  |   3 +
 arch/x86/kernel/cpu/sgx/main.c    | 151 ++++++++++++++++++++++++++++++
 arch/x86/kernel/cpu/sgx/reclaim.c |  82 ++++++++++++++++
 arch/x86/kernel/cpu/sgx/sgx.h     |  70 ++++++++++++++
 6 files changed, 321 insertions(+)
 create mode 100644 arch/x86/kernel/cpu/sgx/Makefile
 create mode 100644 arch/x86/kernel/cpu/sgx/main.c
 create mode 100644 arch/x86/kernel/cpu/sgx/reclaim.c
 create mode 100644 arch/x86/kernel/cpu/sgx/sgx.h

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 1197b5596d5a..4a7e7e484783 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1947,6 +1947,20 @@ config X86_INTEL_TSX_MODE_AUTO
 	  side channel attacks- equals the tsx=auto command line parameter.
 endchoice
 
+config INTEL_SGX
+	bool "Intel SGX"
+	depends on X86_64 && CPU_SUP_INTEL
+	select SRCU
+	select MMU_NOTIFIER
+	help
+	  Intel(R) SGX is a set of CPU instructions that can be used by
+	  applications to set aside private regions of code and data, referred
+	  to as enclaves. An enclave's private memory can only be accessed by
+	  code running within the enclave. Accesses from outside the enclave,
+	  including other enclaves, are disallowed by hardware.
+
+	  If unsure, say N.
+
 config EFI
 	bool "EFI runtime service support"
 	depends on ACPI
diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
index 7dc4ad68eb41..45534fb81007 100644
--- a/arch/x86/kernel/cpu/Makefile
+++ b/arch/x86/kernel/cpu/Makefile
@@ -46,6 +46,7 @@ obj-$(CONFIG_X86_MCE)			+= mce/
 obj-$(CONFIG_MTRR)			+= mtrr/
 obj-$(CONFIG_MICROCODE)			+= microcode/
 obj-$(CONFIG_X86_CPU_RESCTRL)		+= resctrl/
+obj-$(CONFIG_INTEL_SGX)			+= sgx/
 
 obj-$(CONFIG_X86_LOCAL_APIC)		+= perfctr-watchdog.o
 
diff --git a/arch/x86/kernel/cpu/sgx/Makefile b/arch/x86/kernel/cpu/sgx/Makefile
new file mode 100644
index 000000000000..2dec75916a5e
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/Makefile
@@ -0,0 +1,3 @@
+obj-y += \
+	main.o \
+	reclaim.o
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
new file mode 100644
index 000000000000..38424c1e8341
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -0,0 +1,151 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-17 Intel Corporation.
+
+#include <linux/freezer.h>
+#include <linux/highmem.h>
+#include <linux/kthread.h>
+#include <linux/pagemap.h>
+#include <linux/ratelimit.h>
+#include <linux/sched/signal.h>
+#include <linux/slab.h>
+#include "encls.h"
+
+struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
+int sgx_nr_epc_sections;
+
+static void __init sgx_free_epc_section(struct sgx_epc_section *section)
+{
+	struct sgx_epc_page *page;
+
+	while (!list_empty(&section->page_list)) {
+		page = list_first_entry(&section->page_list,
+					struct sgx_epc_page, list);
+		list_del(&page->list);
+		kfree(page);
+	}
+
+	while (!list_empty(&section->unsanitized_page_list)) {
+		page = list_first_entry(&section->unsanitized_page_list,
+					struct sgx_epc_page, list);
+		list_del(&page->list);
+		kfree(page);
+	}
+
+	memunmap(section->va);
+}
+
+static bool __init sgx_alloc_epc_section(u64 addr, u64 size,
+					 unsigned long index,
+					 struct sgx_epc_section *section)
+{
+	unsigned long nr_pages = size >> PAGE_SHIFT;
+	struct sgx_epc_page *page;
+	unsigned long i;
+
+	section->va = memremap(addr, size, MEMREMAP_WB);
+	if (!section->va)
+		return false;
+
+	section->pa = addr;
+	spin_lock_init(&section->lock);
+	INIT_LIST_HEAD(&section->page_list);
+	INIT_LIST_HEAD(&section->unsanitized_page_list);
+
+	for (i = 0; i < nr_pages; i++) {
+		page = kzalloc(sizeof(*page), GFP_KERNEL);
+		if (!page)
+			goto err_out;
+
+		page->desc = (addr + (i << PAGE_SHIFT)) | index;
+		list_add_tail(&page->list, &section->unsanitized_page_list);
+	}
+
+	return true;
+
+err_out:
+	sgx_free_epc_section(section);
+	return false;
+}
+
+static void __init sgx_page_cache_teardown(void)
+{
+	int i;
+
+	for (i = 0; i < sgx_nr_epc_sections; i++)
+		sgx_free_epc_section(&sgx_epc_sections[i]);
+}
+
+/**
+ * A section metric is concatenated in a way that @low bits 12-31 define the
+ * bits 12-31 of the metric and @high bits 0-19 define the bits 32-51 of the
+ * metric.
+ */
+static inline u64 __init sgx_calc_section_metric(u64 low, u64 high)
+{
+	return (low & GENMASK_ULL(31, 12)) +
+	       ((high & GENMASK_ULL(19, 0)) << 32);
+}
+
+static bool __init sgx_page_cache_init(void)
+{
+	u32 eax, ebx, ecx, edx, type;
+	u64 pa, size;
+	int i;
+
+	for (i = 0; i <= ARRAY_SIZE(sgx_epc_sections); i++) {
+		cpuid_count(SGX_CPUID, i + SGX_CPUID_FIRST_VARIABLE_SUB_LEAF,
+			    &eax, &ebx, &ecx, &edx);
+
+		type = eax & SGX_CPUID_SUB_LEAF_TYPE_MASK;
+		if (type == SGX_CPUID_SUB_LEAF_INVALID)
+			break;
+
+		if (type != SGX_CPUID_SUB_LEAF_EPC_SECTION) {
+			pr_err_once("Unknown EPC section type: %u\n", type);
+			break;
+		}
+
+		if (i == ARRAY_SIZE(sgx_epc_sections)) {
+			pr_warn("No free slot for an EPC section\n");
+			break;
+		}
+
+		pa = sgx_calc_section_metric(eax, ebx);
+		size = sgx_calc_section_metric(ecx, edx);
+
+		pr_info("EPC section 0x%llx-0x%llx\n", pa, pa + size - 1);
+
+		if (!sgx_alloc_epc_section(pa, size, i, &sgx_epc_sections[i])) {
+			pr_err("No free memory for an EPC section\n");
+			break;
+		}
+
+		sgx_nr_epc_sections++;
+	}
+
+	if (!sgx_nr_epc_sections) {
+		pr_err("There are zero EPC sections.\n");
+		return false;
+	}
+
+	return true;
+}
+
+static void __init sgx_init(void)
+{
+	if (!boot_cpu_has(X86_FEATURE_SGX))
+		return;
+
+	if (!sgx_page_cache_init())
+		return;
+
+	if (!sgx_page_reclaimer_init())
+		goto err_page_cache;
+
+	return;
+
+err_page_cache:
+	sgx_page_cache_teardown();
+}
+
+arch_initcall(sgx_init);
diff --git a/arch/x86/kernel/cpu/sgx/reclaim.c b/arch/x86/kernel/cpu/sgx/reclaim.c
new file mode 100644
index 000000000000..215371588a25
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/reclaim.c
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-19 Intel Corporation.
+
+#include <linux/freezer.h>
+#include <linux/highmem.h>
+#include <linux/kthread.h>
+#include <linux/pagemap.h>
+#include <linux/ratelimit.h>
+#include <linux/slab.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/signal.h>
+#include "encls.h"
+
+struct task_struct *ksgxswapd_tsk;
+
+static void sgx_sanitize_section(struct sgx_epc_section *section)
+{
+	struct sgx_epc_page *page;
+	LIST_HEAD(secs_list);
+	int ret;
+
+	while (!list_empty(&section->unsanitized_page_list)) {
+		if (kthread_should_stop())
+			return;
+
+		spin_lock(&section->lock);
+
+		page = list_first_entry(&section->unsanitized_page_list,
+					struct sgx_epc_page, list);
+
+		ret = __eremove(sgx_epc_addr(page));
+		if (!ret)
+			list_move(&page->list, &section->page_list);
+		else
+			list_move_tail(&page->list, &secs_list);
+
+		spin_unlock(&section->lock);
+
+		cond_resched();
+	}
+}
+
+static int ksgxswapd(void *p)
+{
+	int i;
+
+	set_freezable();
+
+	/*
+	 * Reset all pages to uninitialized state. Pages could be in initialized
+	 * on kmemexec.
+	 */
+	for (i = 0; i < sgx_nr_epc_sections; i++)
+		sgx_sanitize_section(&sgx_epc_sections[i]);
+
+	/*
+	 * 2nd round for the SECS pages as they cannot be removed when they
+	 * still hold child pages.
+	 */
+	for (i = 0; i < sgx_nr_epc_sections; i++) {
+		sgx_sanitize_section(&sgx_epc_sections[i]);
+
+		/* Should never happen. */
+		if (!list_empty(&sgx_epc_sections[i].unsanitized_page_list))
+			WARN(1, "EPC section %d has unsanitized pages.\n", i);
+	}
+
+	return 0;
+}
+
+bool __init sgx_page_reclaimer_init(void)
+{
+	struct task_struct *tsk;
+
+	tsk = kthread_run(ksgxswapd, NULL, "ksgxswapd");
+	if (IS_ERR(tsk))
+		return false;
+
+	ksgxswapd_tsk = tsk;
+
+	return true;
+}
diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h
new file mode 100644
index 000000000000..aad30980be32
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/sgx.h
@@ -0,0 +1,70 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
+#ifndef _X86_SGX_H
+#define _X86_SGX_H
+
+#include <linux/bitops.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/rwsem.h>
+#include <linux/types.h>
+#include <asm/asm.h>
+#include "arch.h"
+
+#undef pr_fmt
+#define pr_fmt(fmt) "sgx: " fmt
+
+struct sgx_epc_page {
+	unsigned long desc;
+	struct list_head list;
+};
+
+/**
+ * struct sgx_epc_section
+ *
+ * The firmware can define multiple chunks of EPC to the different areas of the
+ * physical memory e.g. for memory areas of the each node. This structure is
+ * used to store EPC pages for one EPC section and virtual memory area where
+ * the pages have been mapped.
+ */
+struct sgx_epc_section {
+	unsigned long pa;
+	void *va;
+	struct list_head page_list;
+	struct list_head unsanitized_page_list;
+	spinlock_t lock;
+};
+
+/**
+ * enum sgx_epc_page_desc - bits and masks for an EPC page's descriptor
+ * %SGX_EPC_SECTION_MASK:	SGX allows to have multiple EPC sections in the
+ *				physical memory. The existing and near-future
+ *				hardware defines at most eight sections, hence
+ *				three bits to hold a section.
+ */
+enum sgx_epc_page_desc {
+	SGX_EPC_SECTION_MASK			= GENMASK_ULL(3, 0),
+	/* bits 12-63 are reserved for the physical page address of the page */
+};
+
+#define SGX_MAX_EPC_SECTIONS (SGX_EPC_SECTION_MASK + 1)
+
+extern struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
+
+static inline struct sgx_epc_section *sgx_epc_section(struct sgx_epc_page *page)
+{
+	return &sgx_epc_sections[page->desc & SGX_EPC_SECTION_MASK];
+}
+
+static inline void *sgx_epc_addr(struct sgx_epc_page *page)
+{
+	struct sgx_epc_section *section = sgx_epc_section(page);
+
+	return section->va + (page->desc & PAGE_MASK) - section->pa;
+}
+
+extern int sgx_nr_epc_sections;
+extern struct task_struct *ksgxswapd_tsk;
+
+bool __init sgx_page_reclaimer_init(void);
+
+#endif /* _X86_SGX_H */
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
  2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
                   ` (6 preceding siblings ...)
  2020-05-15  0:43 ` [PATCH v30 07/20] x86/sgx: Enumerate and track EPC sections Jarkko Sakkinen
@ 2020-05-15  0:43 ` Jarkko Sakkinen
  2020-05-26 12:52   ` Borislav Petkov
  2020-05-15  0:43 ` [PATCH v30 09/20] mm: Introduce vm_ops->may_mprotect() Jarkko Sakkinen
                   ` (12 subsequent siblings)
  20 siblings, 1 reply; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-15  0:43 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: akpm, dave.hansen, sean.j.christopherson, nhorman, npmccallum,
	haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp, josh, luto,
	kai.huang, rientjes, cedric.xing, puiterwijk, Jarkko Sakkinen,
	Jethro Beekman

Add functions for allocating page from Enclave Page Cache (EPC). A page is
allocated by going through the EPC sections and returning the first free
page.

When a page is freed, it might have a valid state, which means that the
callee has assigned it to an enclave, which are protected memory ares used
to run code protected from outside access. The page is returned back to the
invalid state with ENCLS[EREMOVE] [1].

[1] Intel SDM: 40.3 INTEL® SGX SYSTEM LEAF FUNCTION REFERENCE

Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Jethro Beekman <jethro@fortanix.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 arch/x86/kernel/cpu/sgx/main.c | 60 ++++++++++++++++++++++++++++++++++
 arch/x86/kernel/cpu/sgx/sgx.h  |  3 ++
 2 files changed, 63 insertions(+)

diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 38424c1e8341..60d82e7537c8 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -13,6 +13,66 @@
 struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
 int sgx_nr_epc_sections;
 
+static struct sgx_epc_page *__sgx_try_alloc_page(struct sgx_epc_section *section)
+{
+	struct sgx_epc_page *page;
+
+	if (list_empty(&section->page_list))
+		return NULL;
+
+	page = list_first_entry(&section->page_list, struct sgx_epc_page, list);
+	list_del_init(&page->list);
+	return page;
+}
+
+/**
+ * sgx_try_alloc_page() - Allocate an EPC page
+ *
+ * Try to grab a page from the free EPC page list.
+ *
+ * Return:
+ *   a pointer to a &struct sgx_epc_page instance,
+ *   -errno on error
+ */
+struct sgx_epc_page *sgx_try_alloc_page(void)
+{
+	struct sgx_epc_section *section;
+	struct sgx_epc_page *page;
+	int i;
+
+	for (i = 0; i < sgx_nr_epc_sections; i++) {
+		section = &sgx_epc_sections[i];
+		spin_lock(&section->lock);
+		page = __sgx_try_alloc_page(section);
+		spin_unlock(&section->lock);
+
+		if (page)
+			return page;
+	}
+
+	return ERR_PTR(-ENOMEM);
+}
+
+/**
+ * sgx_free_page() - Free an EPC page
+ * @page:	pointer a previously allocated EPC page
+ *
+ * EREMOVE an EPC page and insert it back to the list of free pages.
+ */
+void sgx_free_page(struct sgx_epc_page *page)
+{
+	struct sgx_epc_section *section = sgx_epc_section(page);
+	int ret;
+
+	ret = __eremove(sgx_epc_addr(page));
+	if (WARN_ONCE(ret, "EREMOVE returned %d (0x%x)", ret, ret))
+		return;
+
+	spin_lock(&section->lock);
+	list_add_tail(&page->list, &section->page_list);
+	spin_unlock(&section->lock);
+}
+
 static void __init sgx_free_epc_section(struct sgx_epc_section *section)
 {
 	struct sgx_epc_page *page;
diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h
index aad30980be32..aa85f85412d8 100644
--- a/arch/x86/kernel/cpu/sgx/sgx.h
+++ b/arch/x86/kernel/cpu/sgx/sgx.h
@@ -67,4 +67,7 @@ extern struct task_struct *ksgxswapd_tsk;
 
 bool __init sgx_page_reclaimer_init(void);
 
+struct sgx_epc_page *sgx_try_alloc_page(void);
+void sgx_free_page(struct sgx_epc_page *page);
+
 #endif /* _X86_SGX_H */
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH v30 09/20] mm: Introduce vm_ops->may_mprotect()
  2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
                   ` (7 preceding siblings ...)
  2020-05-15  0:43 ` [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages Jarkko Sakkinen
@ 2020-05-15  0:43 ` Jarkko Sakkinen
  2020-05-29 12:10   ` Borislav Petkov
  2020-05-29 18:28   ` Dave Hansen
  2020-05-15  0:44 ` [PATCH v30 10/20] x86/sgx: Linux Enclave Driver Jarkko Sakkinen
                   ` (11 subsequent siblings)
  20 siblings, 2 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-15  0:43 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: akpm, dave.hansen, sean.j.christopherson, nhorman, npmccallum,
	haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp, josh, luto,
	kai.huang, rientjes, cedric.xing, puiterwijk, Jethro Beekman,
	Jarkko Sakkinen

From: Sean Christopherson <sean.j.christopherson@intel.com>

Add vm_ops()->may_mprotect() to check additional constrains set by a
subsystem for a mprotect() call.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Jethro Beekman <jethro@fortanix.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 include/linux/mm.h |  2 ++
 mm/mprotect.c      | 14 +++++++++++---
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 5a323422d783..dbcc2846b3b8 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -546,6 +546,8 @@ struct vm_operations_struct {
 	void (*close)(struct vm_area_struct * area);
 	int (*split)(struct vm_area_struct * area, unsigned long addr);
 	int (*mremap)(struct vm_area_struct * area);
+	int (*may_mprotect)(struct vm_area_struct *vma, unsigned long start,
+			    unsigned long end, unsigned long prot);
 	vm_fault_t (*fault)(struct vm_fault *vmf);
 	vm_fault_t (*huge_fault)(struct vm_fault *vmf,
 			enum page_entry_size pe_size);
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 494192ca954b..079ba92df377 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -603,13 +603,21 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
 			goto out;
 		}
 
+		tmp = vma->vm_end;
+		if (tmp > end)
+			tmp = end;
+
+		if (vma->vm_ops && vma->vm_ops->may_mprotect) {
+			error = vma->vm_ops->may_mprotect(vma, nstart, tmp,
+							  prot);
+			if (error)
+				goto out;
+		}
+
 		error = security_file_mprotect(vma, reqprot, prot);
 		if (error)
 			goto out;
 
-		tmp = vma->vm_end;
-		if (tmp > end)
-			tmp = end;
 		error = mprotect_fixup(vma, &prev, nstart, tmp, newflags);
 		if (error)
 			goto out;
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH v30 10/20] x86/sgx: Linux Enclave Driver
  2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
                   ` (8 preceding siblings ...)
  2020-05-15  0:43 ` [PATCH v30 09/20] mm: Introduce vm_ops->may_mprotect() Jarkko Sakkinen
@ 2020-05-15  0:44 ` Jarkko Sakkinen
  2020-05-21 19:12   ` Sean Christopherson
  2020-05-22  3:33   ` Sean Christopherson
  2020-05-15  0:44 ` [PATCH v30 11/20] x86/sgx: Add provisioning Jarkko Sakkinen
                   ` (10 subsequent siblings)
  20 siblings, 2 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-15  0:44 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: akpm, dave.hansen, sean.j.christopherson, nhorman, npmccallum,
	haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp, josh, luto,
	kai.huang, rientjes, cedric.xing, puiterwijk, Jarkko Sakkinen,
	linux-security-module, Suresh Siddha, Jethro Beekman,
	Haitao Huang, Chunyang Hui, Jordan Hand, Seth Moore

Intel Software Guard eXtensions (SGX) is a set of CPU instructions that
can be used by applications to set aside private regions of code and
data. The code outside the SGX hosted software entity is disallowed to
access the memory inside the enclave enforced by the CPU. We call these
entities as enclaves.

This commit implements a driver that provides an ioctl API to construct
and run enclaves. Enclaves are constructed from pages residing in
reserved physical memory areas. The contents of these pages can only be
accessed when they are mapped as part of an enclave, by a hardware
thread running inside the enclave.

The starting state of an enclave consists of a fixed measured set of
pages that are copied to the EPC during the construction process by
using ENCLS leaf functions and Software Enclave Control Structure (SECS)
that defines the enclave properties.

Enclave are constructed by using ENCLS leaf functions ECREATE, EADD and
EINIT. ECREATE initializes SECS, EADD copies pages from system memory to
the EPC and EINIT check a given signed measurement and moves the enclave
into a state ready for execution.

An initialized enclave can only be accessed through special Thread Control
Structure (TCS) pages by using ENCLU (ring-3 only) leaf EENTER.  This leaf
function converts a thread into enclave mode and continues the execution in
the offset defined by the TCS provided to EENTER. An enclave is exited
through syscall, exception, interrupts or by explicitly calling another
ENCLU leaf EEXIT.

The permissions, which enclave page is added will set the limit for maximum
permissions that can be set for mmap() and mprotect(). This will
effectively allow to build different security schemes between producers and
consumers of enclaves. Later on we can increase granularity with LSM hooks
for page addition (i.e. for producers) and mapping of the enclave (i.e. for
consumers)

Cc: linux-security-module@vger.kernel.org
Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Co-developed-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: Jethro Beekman <jethro@fortanix.com>
Tested-by: Jethro Beekman <jethro@fortanix.com>
Tested-by: Haitao Huang <haitao.huang@linux.intel.com>
Tested-by: Chunyang Hui <sanqian.hcy@antfin.com>
Tested-by: Jordan Hand <jorhand@linux.microsoft.com>
Tested-by: Nathaniel McCallum <npmccallum@redhat.com>
Tested-by: Seth Moore <sethmo@google.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 .../userspace-api/ioctl/ioctl-number.rst      |   1 +
 arch/x86/include/uapi/asm/sgx.h               |  66 ++
 arch/x86/kernel/cpu/sgx/Makefile              |   3 +
 arch/x86/kernel/cpu/sgx/driver.c              | 194 +++++
 arch/x86/kernel/cpu/sgx/driver.h              |  30 +
 arch/x86/kernel/cpu/sgx/encl.c                | 332 +++++++++
 arch/x86/kernel/cpu/sgx/encl.h                |  87 +++
 arch/x86/kernel/cpu/sgx/encls.h               |   5 +-
 arch/x86/kernel/cpu/sgx/ioctl.c               | 687 ++++++++++++++++++
 arch/x86/kernel/cpu/sgx/main.c                |  12 +-
 arch/x86/kernel/cpu/sgx/reclaim.c             |   1 +
 11 files changed, 1414 insertions(+), 4 deletions(-)
 create mode 100644 arch/x86/include/uapi/asm/sgx.h
 create mode 100644 arch/x86/kernel/cpu/sgx/driver.c
 create mode 100644 arch/x86/kernel/cpu/sgx/driver.h
 create mode 100644 arch/x86/kernel/cpu/sgx/encl.c
 create mode 100644 arch/x86/kernel/cpu/sgx/encl.h
 create mode 100644 arch/x86/kernel/cpu/sgx/ioctl.c

diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
index f759edafd938..a9a418a9918c 100644
--- a/Documentation/userspace-api/ioctl/ioctl-number.rst
+++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
@@ -320,6 +320,7 @@ Code  Seq#    Include File                                           Comments
                                                                      <mailto:tlewis@mindspring.com>
 0xA3  90-9F  linux/dtlk.h
 0xA4  00-1F  uapi/linux/tee.h                                        Generic TEE subsystem
+0xA4  00-1F  uapi/asm/sgx.h                                          Intel SGX subsystem (a legit conflict as TEE and SGX do not co-exist)
 0xAA  00-3F  linux/uapi/linux/userfaultfd.h
 0xAB  00-1F  linux/nbd.h
 0xAC  00-1F  linux/raw.h
diff --git a/arch/x86/include/uapi/asm/sgx.h b/arch/x86/include/uapi/asm/sgx.h
new file mode 100644
index 000000000000..5edb08ab8fd0
--- /dev/null
+++ b/arch/x86/include/uapi/asm/sgx.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) WITH Linux-syscall-note */
+/*
+ * Copyright(c) 2016-19 Intel Corporation.
+ */
+#ifndef _UAPI_ASM_X86_SGX_H
+#define _UAPI_ASM_X86_SGX_H
+
+#include <linux/types.h>
+#include <linux/ioctl.h>
+
+/**
+ * enum sgx_epage_flags - page control flags
+ * %SGX_PAGE_MEASURE:	Measure the page contents with a sequence of
+ *			ENCLS[EEXTEND] operations.
+ */
+enum sgx_page_flags {
+	SGX_PAGE_MEASURE	= 0x01,
+};
+
+#define SGX_MAGIC 0xA4
+
+#define SGX_IOC_ENCLAVE_CREATE \
+	_IOW(SGX_MAGIC, 0x00, struct sgx_enclave_create)
+#define SGX_IOC_ENCLAVE_ADD_PAGES \
+	_IOWR(SGX_MAGIC, 0x01, struct sgx_enclave_add_pages)
+#define SGX_IOC_ENCLAVE_INIT \
+	_IOW(SGX_MAGIC, 0x02, struct sgx_enclave_init)
+
+/**
+ * struct sgx_enclave_create - parameter structure for the
+ *                             %SGX_IOC_ENCLAVE_CREATE ioctl
+ * @src:	address for the SECS page data
+ */
+struct sgx_enclave_create  {
+	__u64	src;
+};
+
+/**
+ * struct sgx_enclave_add_pages - parameter structure for the
+ *                                %SGX_IOC_ENCLAVE_ADD_PAGE ioctl
+ * @src:	start address for the page data
+ * @offset:	starting page offset
+ * @length:	length of the data (multiple of the page size)
+ * @secinfo:	address for the SECINFO data
+ * @flags:	page control flags
+ * @count:	number of bytes added (multiple of the page size)
+ */
+struct sgx_enclave_add_pages {
+	__u64	src;
+	__u64	offset;
+	__u64	length;
+	__u64	secinfo;
+	__u64	flags;
+	__u64	count;
+};
+
+/**
+ * struct sgx_enclave_init - parameter structure for the
+ *                           %SGX_IOC_ENCLAVE_INIT ioctl
+ * @sigstruct:	address for the SIGSTRUCT data
+ */
+struct sgx_enclave_init {
+	__u64 sigstruct;
+};
+
+#endif /* _UAPI_ASM_X86_SGX_H */
diff --git a/arch/x86/kernel/cpu/sgx/Makefile b/arch/x86/kernel/cpu/sgx/Makefile
index 2dec75916a5e..f8d32da3a67a 100644
--- a/arch/x86/kernel/cpu/sgx/Makefile
+++ b/arch/x86/kernel/cpu/sgx/Makefile
@@ -1,3 +1,6 @@
 obj-y += \
+	driver.o \
+	encl.o \
+	ioctl.o \
 	main.o \
 	reclaim.o
diff --git a/arch/x86/kernel/cpu/sgx/driver.c b/arch/x86/kernel/cpu/sgx/driver.c
new file mode 100644
index 000000000000..b4aa7b9f8376
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/driver.c
@@ -0,0 +1,194 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-18 Intel Corporation.
+
+#include <linux/acpi.h>
+#include <linux/miscdevice.h>
+#include <linux/mman.h>
+#include <linux/security.h>
+#include <linux/suspend.h>
+#include <asm/traps.h>
+#include "driver.h"
+#include "encl.h"
+
+MODULE_DESCRIPTION("Intel SGX Enclave Driver");
+MODULE_AUTHOR("Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>");
+MODULE_LICENSE("Dual BSD/GPL");
+
+u64 sgx_encl_size_max_32;
+u64 sgx_encl_size_max_64;
+u32 sgx_misc_reserved_mask;
+u64 sgx_attributes_reserved_mask;
+u64 sgx_xfrm_reserved_mask = ~0x3;
+u32 sgx_xsave_size_tbl[64];
+
+static int sgx_open(struct inode *inode, struct file *file)
+{
+	struct sgx_encl *encl;
+	int ret;
+
+	encl = kzalloc(sizeof(*encl), GFP_KERNEL);
+	if (!encl)
+		return -ENOMEM;
+
+	atomic_set(&encl->flags, 0);
+	kref_init(&encl->refcount);
+	INIT_RADIX_TREE(&encl->page_tree, GFP_KERNEL);
+	mutex_init(&encl->lock);
+	INIT_LIST_HEAD(&encl->mm_list);
+	spin_lock_init(&encl->mm_lock);
+
+	ret = init_srcu_struct(&encl->srcu);
+	if (ret) {
+		kfree(encl);
+		return ret;
+	}
+
+	file->private_data = encl;
+
+	return 0;
+}
+
+static int sgx_release(struct inode *inode, struct file *file)
+{
+	struct sgx_encl *encl = file->private_data;
+	struct sgx_encl_mm *encl_mm;
+
+	for ( ; ; )  {
+		spin_lock(&encl->mm_lock);
+
+		if (list_empty(&encl->mm_list)) {
+			encl_mm = NULL;
+		} else {
+			encl_mm = list_first_entry(&encl->mm_list,
+						   struct sgx_encl_mm, list);
+			list_del_rcu(&encl_mm->list);
+		}
+
+		spin_unlock(&encl->mm_lock);
+
+		/* The list is empty, ready to go. */
+		if (!encl_mm)
+			break;
+
+		synchronize_srcu(&encl->srcu);
+		mmu_notifier_unregister(&encl_mm->mmu_notifier, encl_mm->mm);
+		kfree(encl_mm);
+	};
+
+	mutex_lock(&encl->lock);
+	atomic_or(SGX_ENCL_DEAD, &encl->flags);
+	mutex_unlock(&encl->lock);
+
+	kref_put(&encl->refcount, sgx_encl_release);
+	return 0;
+}
+
+#ifdef CONFIG_COMPAT
+static long sgx_compat_ioctl(struct file *filep, unsigned int cmd,
+			      unsigned long arg)
+{
+	return sgx_ioctl(filep, cmd, arg);
+}
+#endif
+
+static int sgx_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	struct sgx_encl *encl = file->private_data;
+	int ret;
+
+	ret = sgx_encl_may_map(encl, vma->vm_start, vma->vm_end,
+			       vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC));
+	if (ret)
+		return ret;
+
+	ret = sgx_encl_mm_add(encl, vma->vm_mm);
+	if (ret)
+		return ret;
+
+	vma->vm_ops = &sgx_vm_ops;
+	vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP | VM_IO;
+	vma->vm_private_data = encl;
+
+	return 0;
+}
+
+static unsigned long sgx_get_unmapped_area(struct file *file,
+					   unsigned long addr,
+					   unsigned long len,
+					   unsigned long pgoff,
+					   unsigned long flags)
+{
+	if (flags & MAP_PRIVATE)
+		return -EINVAL;
+
+	if (flags & MAP_FIXED)
+		return addr;
+
+	return current->mm->get_unmapped_area(file, addr, len, pgoff, flags);
+}
+
+static const struct file_operations sgx_encl_fops = {
+	.owner			= THIS_MODULE,
+	.open			= sgx_open,
+	.release		= sgx_release,
+	.unlocked_ioctl		= sgx_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl		= sgx_compat_ioctl,
+#endif
+	.mmap			= sgx_mmap,
+	.get_unmapped_area	= sgx_get_unmapped_area,
+};
+
+const struct file_operations sgx_provision_fops = {
+	.owner			= THIS_MODULE,
+};
+
+static struct miscdevice sgx_dev_enclave = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "enclave",
+	.nodename = "sgx/enclave",
+	.fops = &sgx_encl_fops,
+};
+
+int __init sgx_drv_init(void)
+{
+	unsigned int eax, ebx, ecx, edx;
+	u64 attr_mask, xfrm_mask;
+	int ret;
+	int i;
+
+	if (!boot_cpu_has(X86_FEATURE_SGX_LC)) {
+		pr_info("The public key MSRs are not writable.\n");
+		return -ENODEV;
+	}
+
+	cpuid_count(SGX_CPUID, 0, &eax, &ebx, &ecx, &edx);
+	sgx_misc_reserved_mask = ~ebx | SGX_MISC_RESERVED_MASK;
+	sgx_encl_size_max_64 = 1ULL << ((edx >> 8) & 0xFF);
+	sgx_encl_size_max_32 = 1ULL << (edx & 0xFF);
+
+	cpuid_count(SGX_CPUID, 1, &eax, &ebx, &ecx, &edx);
+
+	attr_mask = (((u64)ebx) << 32) + (u64)eax;
+	sgx_attributes_reserved_mask = ~attr_mask | SGX_ATTR_RESERVED_MASK;
+
+	if (boot_cpu_has(X86_FEATURE_OSXSAVE)) {
+		xfrm_mask = (((u64)edx) << 32) + (u64)ecx;
+
+		for (i = 2; i < 64; i++) {
+			cpuid_count(0x0D, i, &eax, &ebx, &ecx, &edx);
+			if ((1 << i) & xfrm_mask)
+				sgx_xsave_size_tbl[i] = eax + ebx;
+		}
+
+		sgx_xfrm_reserved_mask = ~xfrm_mask;
+	}
+
+	ret = misc_register(&sgx_dev_enclave);
+	if (ret) {
+		pr_err("Creating /dev/sgx/enclave failed with %d.\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
diff --git a/arch/x86/kernel/cpu/sgx/driver.h b/arch/x86/kernel/cpu/sgx/driver.h
new file mode 100644
index 000000000000..e4063923115b
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/driver.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
+#ifndef __ARCH_SGX_DRIVER_H__
+#define __ARCH_SGX_DRIVER_H__
+
+#include <crypto/hash.h>
+#include <linux/kref.h>
+#include <linux/mmu_notifier.h>
+#include <linux/radix-tree.h>
+#include <linux/rwsem.h>
+#include <linux/sched.h>
+#include <linux/workqueue.h>
+#include <uapi/asm/sgx.h>
+#include "sgx.h"
+
+#define SGX_EINIT_SPIN_COUNT	20
+#define SGX_EINIT_SLEEP_COUNT	50
+#define SGX_EINIT_SLEEP_TIME	20
+
+extern u64 sgx_encl_size_max_32;
+extern u64 sgx_encl_size_max_64;
+extern u32 sgx_misc_reserved_mask;
+extern u64 sgx_attributes_reserved_mask;
+extern u64 sgx_xfrm_reserved_mask;
+extern u32 sgx_xsave_size_tbl[64];
+
+long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg);
+
+int sgx_drv_init(void);
+
+#endif /* __ARCH_X86_SGX_DRIVER_H__ */
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
new file mode 100644
index 000000000000..17e44bf8fa56
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -0,0 +1,332 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-18 Intel Corporation.
+
+#include <linux/lockdep.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/shmem_fs.h>
+#include <linux/suspend.h>
+#include <linux/sched/mm.h>
+#include "arch.h"
+#include "encl.h"
+#include "sgx.h"
+
+static struct sgx_encl_page *sgx_encl_load_page(struct sgx_encl *encl,
+						unsigned long addr)
+{
+	struct sgx_encl_page *entry;
+	unsigned int flags;
+
+	/* If process was forked, VMA is still there but vm_private_data is set
+	 * to NULL.
+	 */
+	if (!encl)
+		return ERR_PTR(-EFAULT);
+
+	flags = atomic_read(&encl->flags);
+
+	if ((flags & SGX_ENCL_DEAD) || !(flags & SGX_ENCL_INITIALIZED))
+		return ERR_PTR(-EFAULT);
+
+	entry = radix_tree_lookup(&encl->page_tree, addr >> PAGE_SHIFT);
+	if (!entry)
+		return ERR_PTR(-EFAULT);
+
+	/* Page is already resident in the EPC. */
+	if (entry->epc_page)
+		return entry;
+
+	return ERR_PTR(-EFAULT);
+}
+
+static void sgx_mmu_notifier_release(struct mmu_notifier *mn,
+				     struct mm_struct *mm)
+{
+	struct sgx_encl_mm *encl_mm =
+		container_of(mn, struct sgx_encl_mm, mmu_notifier);
+	struct sgx_encl_mm *tmp = NULL;
+
+	/*
+	 * The enclave itself can remove encl_mm.  Note, objects can't be moved
+	 * off an RCU protected list, but deletion is ok.
+	 */
+	spin_lock(&encl_mm->encl->mm_lock);
+	list_for_each_entry(tmp, &encl_mm->encl->mm_list, list) {
+		if (tmp == encl_mm) {
+			list_del_rcu(&encl_mm->list);
+			break;
+		}
+	}
+	spin_unlock(&encl_mm->encl->mm_lock);
+
+	if (tmp == encl_mm) {
+		synchronize_srcu(&encl_mm->encl->srcu);
+		mmu_notifier_put(mn);
+	}
+}
+
+static void sgx_mmu_notifier_free(struct mmu_notifier *mn)
+{
+	struct sgx_encl_mm *encl_mm =
+		container_of(mn, struct sgx_encl_mm, mmu_notifier);
+
+	kfree(encl_mm);
+}
+
+static const struct mmu_notifier_ops sgx_mmu_notifier_ops = {
+	.release		= sgx_mmu_notifier_release,
+	.free_notifier		= sgx_mmu_notifier_free,
+};
+
+static struct sgx_encl_mm *sgx_encl_find_mm(struct sgx_encl *encl,
+					    struct mm_struct *mm)
+{
+	struct sgx_encl_mm *encl_mm = NULL;
+	struct sgx_encl_mm *tmp;
+	int idx;
+
+	idx = srcu_read_lock(&encl->srcu);
+
+	list_for_each_entry_rcu(tmp, &encl->mm_list, list) {
+		if (tmp->mm == mm) {
+			encl_mm = tmp;
+			break;
+		}
+	}
+
+	srcu_read_unlock(&encl->srcu, idx);
+
+	return encl_mm;
+}
+
+int sgx_encl_mm_add(struct sgx_encl *encl, struct mm_struct *mm)
+{
+	struct sgx_encl_mm *encl_mm;
+	int ret;
+
+	/* mm_list can be accessed only by a single thread at a time. */
+	lockdep_assert_held_write(&mm->mmap_sem);
+
+	if (atomic_read(&encl->flags) & SGX_ENCL_DEAD)
+		return -EINVAL;
+
+	/*
+	 * mm_structs are kept on mm_list until the mm or the enclave dies,
+	 * i.e. once an mm is off the list, it's gone for good, therefore it's
+	 * impossible to get a false positive on @mm due to a stale mm_list.
+	 */
+	if (sgx_encl_find_mm(encl, mm))
+		return 0;
+
+	encl_mm = kzalloc(sizeof(*encl_mm), GFP_KERNEL);
+	if (!encl_mm)
+		return -ENOMEM;
+
+	encl_mm->encl = encl;
+	encl_mm->mm = mm;
+	encl_mm->mmu_notifier.ops = &sgx_mmu_notifier_ops;
+
+	ret = __mmu_notifier_register(&encl_mm->mmu_notifier, mm);
+	if (ret) {
+		kfree(encl_mm);
+		return ret;
+	}
+
+	spin_lock(&encl->mm_lock);
+	list_add_rcu(&encl_mm->list, &encl->mm_list);
+	spin_unlock(&encl->mm_lock);
+
+	return 0;
+}
+
+static void sgx_vma_open(struct vm_area_struct *vma)
+{
+	struct sgx_encl *encl = vma->vm_private_data;
+
+	if (!encl)
+		return;
+
+	if (sgx_encl_mm_add(encl, vma->vm_mm))
+		vma->vm_private_data = NULL;
+}
+
+static unsigned int sgx_vma_fault(struct vm_fault *vmf)
+{
+	unsigned long addr = (unsigned long)vmf->address;
+	struct vm_area_struct *vma = vmf->vma;
+	struct sgx_encl *encl = vma->vm_private_data;
+	struct sgx_encl_page *entry;
+	int ret = VM_FAULT_NOPAGE;
+	unsigned long pfn;
+
+	if (!encl)
+		return VM_FAULT_SIGBUS;
+
+	mutex_lock(&encl->lock);
+
+	entry = sgx_encl_load_page(encl, addr);
+	if (IS_ERR(entry)) {
+		if (unlikely(PTR_ERR(entry) != -EBUSY))
+			ret = VM_FAULT_SIGBUS;
+
+		goto out;
+	}
+
+	if (!follow_pfn(vma, addr, &pfn))
+		goto out;
+
+	ret = vmf_insert_pfn(vma, addr, PFN_DOWN(entry->epc_page->desc));
+	if (ret != VM_FAULT_NOPAGE) {
+		ret = VM_FAULT_SIGBUS;
+		goto out;
+	}
+
+out:
+	mutex_unlock(&encl->lock);
+	return ret;
+}
+
+/**
+ * sgx_encl_may_map() - Check if a requested VMA mapping is allowed
+ * @encl:		an enclave
+ * @start:		lower bound of the address range, inclusive
+ * @end:		upper bound of the address range, exclusive
+ * @vm_prot_bits:	requested protections of the address range
+ *
+ * Iterate through the enclave pages contained within [@start, @end) to verify
+ * the permissions requested by @vm_prot_bits do not exceed that of any enclave
+ * page to be mapped.
+ *
+ * Return:
+ *   0 on success,
+ *   -EACCES if VMA permissions exceed enclave page permissions
+ */
+int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start,
+		     unsigned long end, unsigned long vm_prot_bits)
+{
+	unsigned long idx, idx_start, idx_end;
+	struct sgx_encl_page *page;
+
+	/*
+	 * Disallow RIE tasks as their VMA permissions might conflict with the
+	 * enclave page permissions.
+	 */
+	if (!!(current->personality & READ_IMPLIES_EXEC))
+		return -EACCES;
+
+	idx_start = PFN_DOWN(start);
+	idx_end = PFN_DOWN(end - 1);
+
+	for (idx = idx_start; idx <= idx_end; ++idx) {
+		mutex_lock(&encl->lock);
+		page = radix_tree_lookup(&encl->page_tree, idx);
+		mutex_unlock(&encl->lock);
+
+		if (!page || (~page->vm_max_prot_bits & vm_prot_bits))
+			return -EACCES;
+	}
+
+	return 0;
+}
+
+static int sgx_vma_mprotect(struct vm_area_struct *vma, unsigned long start,
+			    unsigned long end, unsigned long prot)
+{
+	return sgx_encl_may_map(vma->vm_private_data, start, end,
+				calc_vm_prot_bits(prot, 0));
+}
+
+const struct vm_operations_struct sgx_vm_ops = {
+	.open = sgx_vma_open,
+	.fault = sgx_vma_fault,
+	.may_mprotect = sgx_vma_mprotect,
+};
+
+/**
+ * sgx_encl_find - find an enclave
+ * @mm:		mm struct of the current process
+ * @addr:	address in the ELRANGE
+ * @vma:	the resulting VMA
+ *
+ * Find an enclave identified by the given address. Give back a VMA that is
+ * part of the enclave and located in that address. The VMA is given back if it
+ * is a proper enclave VMA even if an &sgx_encl instance does not exist yet
+ * (enclave creation has not been performed).
+ *
+ * Return:
+ *   0 on success,
+ *   -EINVAL if an enclave was not found,
+ *   -ENOENT if the enclave has not been created yet
+ */
+int sgx_encl_find(struct mm_struct *mm, unsigned long addr,
+		  struct vm_area_struct **vma)
+{
+	struct vm_area_struct *result;
+	struct sgx_encl *encl;
+
+	result = find_vma(mm, addr);
+	if (!result || result->vm_ops != &sgx_vm_ops || addr < result->vm_start)
+		return -EINVAL;
+
+	encl = result->vm_private_data;
+	*vma = result;
+
+	return encl ? 0 : -ENOENT;
+}
+
+/**
+ * sgx_encl_destroy() - destroy enclave resources
+ * @encl:	an &sgx_encl instance
+ */
+void sgx_encl_destroy(struct sgx_encl *encl)
+{
+	struct sgx_encl_page *entry;
+	struct radix_tree_iter iter;
+	void **slot;
+
+	atomic_or(SGX_ENCL_DEAD, &encl->flags);
+
+	radix_tree_for_each_slot(slot, &encl->page_tree, &iter, 0) {
+		entry = *slot;
+
+		if (entry->epc_page) {
+			sgx_free_page(entry->epc_page);
+			encl->secs_child_cnt--;
+			entry->epc_page = NULL;
+		}
+
+		radix_tree_delete(&entry->encl->page_tree,
+				  PFN_DOWN(entry->desc));
+		kfree(entry);
+	}
+
+	if (!encl->secs_child_cnt && encl->secs.epc_page) {
+		sgx_free_page(encl->secs.epc_page);
+		encl->secs.epc_page = NULL;
+	}
+}
+
+/**
+ * sgx_encl_release - Destroy an enclave instance
+ * @kref:	address of a kref inside &sgx_encl
+ *
+ * Used together with kref_put(). Frees all the resources associated with the
+ * enclave and the instance itself.
+ */
+void sgx_encl_release(struct kref *ref)
+{
+	struct sgx_encl *encl = container_of(ref, struct sgx_encl, refcount);
+
+	sgx_encl_destroy(encl);
+
+	if (encl->backing)
+		fput(encl->backing);
+
+	WARN_ON_ONCE(!list_empty(&encl->mm_list));
+
+	/* Detect EPC page leak's. */
+	WARN_ON_ONCE(encl->secs_child_cnt);
+	WARN_ON_ONCE(encl->secs.epc_page);
+
+	kfree(encl);
+}
diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h
new file mode 100644
index 000000000000..1d1bc5d590ee
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/encl.h
@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
+/**
+ * Copyright(c) 2016-19 Intel Corporation.
+ */
+#ifndef _X86_ENCL_H
+#define _X86_ENCL_H
+
+#include <linux/cpumask.h>
+#include <linux/kref.h>
+#include <linux/list.h>
+#include <linux/mm_types.h>
+#include <linux/mmu_notifier.h>
+#include <linux/mutex.h>
+#include <linux/notifier.h>
+#include <linux/radix-tree.h>
+#include <linux/srcu.h>
+#include <linux/workqueue.h>
+#include "sgx.h"
+
+/**
+ * enum sgx_encl_page_desc - defines bits for an enclave page's descriptor
+ * %SGX_ENCL_PAGE_ADDR_MASK:		Holds the virtual address of the page.
+ *
+ * The page address for SECS is zero and is used by the subsystem to recognize
+ * the SECS page.
+ */
+enum sgx_encl_page_desc {
+	/* Bits 11:3 are available when the page is not swapped. */
+	SGX_ENCL_PAGE_ADDR_MASK		= PAGE_MASK,
+};
+
+#define SGX_ENCL_PAGE_ADDR(page) \
+	((page)->desc & SGX_ENCL_PAGE_ADDR_MASK)
+
+struct sgx_encl_page {
+	unsigned long desc;
+	unsigned long vm_max_prot_bits;
+	struct sgx_epc_page *epc_page;
+	struct sgx_encl *encl;
+};
+
+enum sgx_encl_flags {
+	SGX_ENCL_CREATED	= BIT(0),
+	SGX_ENCL_INITIALIZED	= BIT(1),
+	SGX_ENCL_DEBUG		= BIT(2),
+	SGX_ENCL_DEAD		= BIT(3),
+	SGX_ENCL_IOCTL		= BIT(4),
+};
+
+struct sgx_encl_mm {
+	struct sgx_encl *encl;
+	struct mm_struct *mm;
+	struct list_head list;
+	struct mmu_notifier mmu_notifier;
+};
+
+struct sgx_encl {
+	atomic_t flags;
+	u64 secs_attributes;
+	u64 allowed_attributes;
+	unsigned int page_cnt;
+	unsigned int secs_child_cnt;
+	struct mutex lock;
+	struct list_head mm_list;
+	spinlock_t mm_lock;
+	struct file *backing;
+	struct kref refcount;
+	struct srcu_struct srcu;
+	unsigned long base;
+	unsigned long size;
+	unsigned long ssaframesize;
+	struct radix_tree_root page_tree;
+	struct sgx_encl_page secs;
+	cpumask_t cpumask;
+};
+
+extern const struct vm_operations_struct sgx_vm_ops;
+
+int sgx_encl_find(struct mm_struct *mm, unsigned long addr,
+		  struct vm_area_struct **vma);
+void sgx_encl_destroy(struct sgx_encl *encl);
+void sgx_encl_release(struct kref *ref);
+int sgx_encl_mm_add(struct sgx_encl *encl, struct mm_struct *mm);
+int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start,
+		     unsigned long end, unsigned long vm_prot_bits);
+
+#endif /* _X86_ENCL_H */
diff --git a/arch/x86/kernel/cpu/sgx/encls.h b/arch/x86/kernel/cpu/sgx/encls.h
index 376cdedb9a43..f716b4328614 100644
--- a/arch/x86/kernel/cpu/sgx/encls.h
+++ b/arch/x86/kernel/cpu/sgx/encls.h
@@ -186,10 +186,9 @@ static inline int __eadd(struct sgx_pageinfo *pginfo, void *addr)
 	return __encls_2(EADD, pginfo, addr);
 }
 
-static inline int __einit(void *sigstruct, struct sgx_einittoken *einittoken,
-			  void *secs)
+static inline int __einit(void *sigstruct, void *token, void *secs)
 {
-	return __encls_ret_3(EINIT, sigstruct, secs, einittoken);
+	return __encls_ret_3(EINIT, sigstruct, secs, token);
 }
 
 static inline int __eremove(void *addr)
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
new file mode 100644
index 000000000000..26d0425d7252
--- /dev/null
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -0,0 +1,687 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-19 Intel Corporation.
+
+#include <asm/mman.h>
+#include <linux/mman.h>
+#include <linux/delay.h>
+#include <linux/file.h>
+#include <linux/hashtable.h>
+#include <linux/highmem.h>
+#include <linux/ratelimit.h>
+#include <linux/sched/signal.h>
+#include <linux/shmem_fs.h>
+#include <linux/slab.h>
+#include <linux/suspend.h>
+#include "driver.h"
+#include "encl.h"
+#include "encls.h"
+
+/* A per-cpu cache for the last known values of IA32_SGXLEPUBKEYHASHx MSRs. */
+static DEFINE_PER_CPU(u64 [4], sgx_lepubkeyhash_cache);
+
+static u32 sgx_calc_ssaframesize(u32 miscselect, u64 xfrm)
+{
+	u32 size_max = PAGE_SIZE;
+	u32 size;
+	int i;
+
+	for (i = 2; i < 64; i++) {
+		if (!((1 << i) & xfrm))
+			continue;
+
+		size = SGX_SSA_GPRS_SIZE + sgx_xsave_size_tbl[i];
+		if (miscselect & SGX_MISC_EXINFO)
+			size += SGX_SSA_MISC_EXINFO_SIZE;
+
+		if (size > size_max)
+			size_max = size;
+	}
+
+	return PFN_UP(size_max);
+}
+
+static int sgx_validate_secs(const struct sgx_secs *secs,
+			     unsigned long ssaframesize)
+{
+	if (secs->size < (2 * PAGE_SIZE) || !is_power_of_2(secs->size))
+		return -EINVAL;
+
+	if (secs->base & (secs->size - 1))
+		return -EINVAL;
+
+	if (secs->miscselect & sgx_misc_reserved_mask ||
+	    secs->attributes & sgx_attributes_reserved_mask ||
+	    secs->xfrm & sgx_xfrm_reserved_mask)
+		return -EINVAL;
+
+	if (secs->attributes & SGX_ATTR_MODE64BIT) {
+		if (secs->size > sgx_encl_size_max_64)
+			return -EINVAL;
+	} else if (secs->size > sgx_encl_size_max_32)
+		return -EINVAL;
+
+	if (!(secs->xfrm & XFEATURE_MASK_FP) ||
+	    !(secs->xfrm & XFEATURE_MASK_SSE) ||
+	    (((secs->xfrm >> XFEATURE_BNDREGS) & 1) !=
+	     ((secs->xfrm >> XFEATURE_BNDCSR) & 1)))
+		return -EINVAL;
+
+	if (!secs->ssa_frame_size || ssaframesize > secs->ssa_frame_size)
+		return -EINVAL;
+
+	if (memchr_inv(secs->reserved1, 0, sizeof(secs->reserved1)) ||
+	    memchr_inv(secs->reserved2, 0, sizeof(secs->reserved2)) ||
+	    memchr_inv(secs->reserved3, 0, sizeof(secs->reserved3)) ||
+	    memchr_inv(secs->reserved4, 0, sizeof(secs->reserved4)))
+		return -EINVAL;
+
+	return 0;
+}
+
+static struct sgx_encl_page *sgx_encl_page_alloc(struct sgx_encl *encl,
+						 unsigned long offset,
+						 u64 secinfo_flags)
+{
+	struct sgx_encl_page *encl_page;
+	unsigned long prot;
+
+	encl_page = kzalloc(sizeof(*encl_page), GFP_KERNEL);
+	if (!encl_page)
+		return ERR_PTR(-ENOMEM);
+
+	encl_page->desc = encl->base + offset;
+	encl_page->encl = encl;
+
+	prot = _calc_vm_trans(secinfo_flags, SGX_SECINFO_R, PROT_READ)  |
+	       _calc_vm_trans(secinfo_flags, SGX_SECINFO_W, PROT_WRITE) |
+	       _calc_vm_trans(secinfo_flags, SGX_SECINFO_X, PROT_EXEC);
+
+	/*
+	 * TCS pages must always RW set for CPU access while the SECINFO
+	 * permissions are *always* zero - the CPU ignores the user provided
+	 * values and silently overwrites them with zero permissions.
+	 */
+	if ((secinfo_flags & SGX_SECINFO_PAGE_TYPE_MASK) == SGX_SECINFO_TCS)
+		prot |= PROT_READ | PROT_WRITE;
+
+	/* Calculate maximum of the VM flags for the page. */
+	encl_page->vm_max_prot_bits = calc_vm_prot_bits(prot, 0);
+
+	return encl_page;
+}
+
+static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
+{
+	unsigned long encl_size = secs->size + PAGE_SIZE;
+	struct sgx_epc_page *secs_epc;
+	unsigned long ssaframesize;
+	struct sgx_pageinfo pginfo;
+	struct sgx_secinfo secinfo;
+	struct file *backing;
+	long ret;
+
+	if (atomic_read(&encl->flags) & SGX_ENCL_CREATED)
+		return -EINVAL;
+
+	ssaframesize = sgx_calc_ssaframesize(secs->miscselect, secs->xfrm);
+	if (sgx_validate_secs(secs, ssaframesize)) {
+		pr_debug("invalid SECS\n");
+		return -EINVAL;
+	}
+
+	backing = shmem_file_setup("SGX backing", encl_size + (encl_size >> 5),
+				   VM_NORESERVE);
+	if (IS_ERR(backing))
+		return PTR_ERR(backing);
+
+	encl->backing = backing;
+
+	secs_epc = sgx_try_alloc_page();
+	if (IS_ERR(secs_epc)) {
+		ret = PTR_ERR(secs_epc);
+		goto err_out_backing;
+	}
+
+	encl->secs.epc_page = secs_epc;
+
+	pginfo.addr = 0;
+	pginfo.contents = (unsigned long)secs;
+	pginfo.metadata = (unsigned long)&secinfo;
+	pginfo.secs = 0;
+	memset(&secinfo, 0, sizeof(secinfo));
+
+	ret = __ecreate((void *)&pginfo, sgx_epc_addr(secs_epc));
+	if (ret) {
+		pr_debug("ECREATE returned %ld\n", ret);
+		goto err_out;
+	}
+
+	if (secs->attributes & SGX_ATTR_DEBUG)
+		atomic_or(SGX_ENCL_DEBUG, &encl->flags);
+
+	encl->secs.encl = encl;
+	encl->secs_attributes = secs->attributes;
+	encl->allowed_attributes |= SGX_ATTR_ALLOWED_MASK;
+	encl->base = secs->base;
+	encl->size = secs->size;
+	encl->ssaframesize = secs->ssa_frame_size;
+
+	/*
+	 * Set SGX_ENCL_CREATED only after the enclave is fully prepped.  This
+	 * allows setting and checking enclave creation without having to take
+	 * encl->lock.
+	 */
+	atomic_or(SGX_ENCL_CREATED, &encl->flags);
+
+	return 0;
+
+err_out:
+	sgx_free_page(encl->secs.epc_page);
+	encl->secs.epc_page = NULL;
+
+err_out_backing:
+	fput(encl->backing);
+	encl->backing = NULL;
+
+	return ret;
+}
+
+/**
+ * sgx_ioc_enclave_create - handler for %SGX_IOC_ENCLAVE_CREATE
+ * @filep:	open file to /dev/sgx
+ * @arg:	userspace pointer to a struct sgx_enclave_create instance
+ *
+ * Allocate kernel data structures for a new enclave and execute ECREATE after
+ * verifying the correctness of the provided SECS.
+ *
+ * Note, enforcement of restricted and disallowed attributes is deferred until
+ * sgx_ioc_enclave_init(), only the architectural correctness of the SECS is
+ * checked by sgx_ioc_enclave_create().
+ *
+ * Return:
+ *   0 on success,
+ *   -errno otherwise
+ */
+static long sgx_ioc_enclave_create(struct sgx_encl *encl, void __user *arg)
+{
+	struct sgx_enclave_create ecreate;
+	struct page *secs_page;
+	struct sgx_secs *secs;
+	int ret;
+
+	if (copy_from_user(&ecreate, arg, sizeof(ecreate)))
+		return -EFAULT;
+
+	secs_page = alloc_page(GFP_KERNEL);
+	if (!secs_page)
+		return -ENOMEM;
+
+	secs = kmap(secs_page);
+	if (copy_from_user(secs, (void __user *)ecreate.src, sizeof(*secs))) {
+		ret = -EFAULT;
+		goto out;
+	}
+
+	ret = sgx_encl_create(encl, secs);
+
+out:
+	kunmap(secs_page);
+	__free_page(secs_page);
+	return ret;
+}
+
+static int sgx_validate_secinfo(struct sgx_secinfo *secinfo)
+{
+	u64 perm = secinfo->flags & SGX_SECINFO_PERMISSION_MASK;
+	u64 pt = secinfo->flags & SGX_SECINFO_PAGE_TYPE_MASK;
+
+	if (pt != SGX_SECINFO_REG && pt != SGX_SECINFO_TCS)
+		return -EINVAL;
+
+	if ((perm & SGX_SECINFO_W) && !(perm & SGX_SECINFO_R))
+		return -EINVAL;
+
+	/*
+	 * CPU will silently overwrite the permissions as zero, which means
+	 * that we need to validate it ourselves.
+	 */
+	if (pt == SGX_SECINFO_TCS && perm)
+		return -EINVAL;
+
+	if (secinfo->flags & SGX_SECINFO_RESERVED_MASK)
+		return -EINVAL;
+
+	if (memchr_inv(secinfo->reserved, 0, sizeof(secinfo->reserved)))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int __sgx_encl_add_page(struct sgx_encl *encl,
+			       struct sgx_encl_page *encl_page,
+			       struct sgx_epc_page *epc_page,
+			       struct sgx_secinfo *secinfo, unsigned long src)
+{
+	struct sgx_pageinfo pginfo;
+	struct vm_area_struct *vma;
+	struct page *src_page;
+	int ret;
+
+	/* Query vma's VM_MAYEXEC as an indirect path_noexec() check. */
+	if (encl_page->vm_max_prot_bits & VM_EXEC) {
+		vma = find_vma(current->mm, src);
+		if (!vma)
+			return -EFAULT;
+
+		if (!(vma->vm_flags & VM_MAYEXEC))
+			return -EACCES;
+	}
+
+	ret = get_user_pages(src, 1, 0, &src_page, NULL);
+	if (ret < 1)
+		return ret;
+
+	pginfo.secs = (unsigned long)sgx_epc_addr(encl->secs.epc_page);
+	pginfo.addr = SGX_ENCL_PAGE_ADDR(encl_page);
+	pginfo.metadata = (unsigned long)secinfo;
+	pginfo.contents = (unsigned long)kmap_atomic(src_page);
+
+	ret = __eadd(&pginfo, sgx_epc_addr(epc_page));
+
+	kunmap_atomic((void *)pginfo.contents);
+	put_page(src_page);
+
+	return ret ? -EIO : 0;
+}
+
+static int __sgx_encl_extend(struct sgx_encl *encl,
+			     struct sgx_epc_page *epc_page)
+{
+	int ret;
+	int i;
+
+	for (i = 0; i < 16; i++) {
+		ret = __eextend(sgx_epc_addr(encl->secs.epc_page),
+				sgx_epc_addr(epc_page) + (i * 0x100));
+		if (ret) {
+			if (encls_failed(ret))
+				ENCLS_WARN(ret, "EEXTEND");
+			return -EIO;
+		}
+	}
+
+	return 0;
+}
+
+static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long src,
+			     unsigned long offset, unsigned long length,
+			     struct sgx_secinfo *secinfo, unsigned long flags)
+{
+	struct sgx_encl_page *encl_page;
+	struct sgx_epc_page *epc_page;
+	int ret;
+
+	encl_page = sgx_encl_page_alloc(encl, offset, secinfo->flags);
+	if (IS_ERR(encl_page))
+		return PTR_ERR(encl_page);
+
+	epc_page = sgx_try_alloc_page();
+	if (IS_ERR(epc_page)) {
+		kfree(encl_page);
+		return PTR_ERR(epc_page);
+	}
+
+	if (atomic_read(&encl->flags) &
+	    (SGX_ENCL_INITIALIZED | SGX_ENCL_DEAD)) {
+		ret = -EFAULT;
+		goto err_out_free;
+	}
+
+	down_read(&current->mm->mmap_sem);
+	mutex_lock(&encl->lock);
+
+	/*
+	 * Insert prior to EADD in case of OOM.  EADD modifies MRENCLAVE, i.e.
+	 * can't be gracefully unwound, while failure on EADD/EXTEND is limited
+	 * to userspace errors (or kernel/hardware bugs).
+	 */
+	ret = radix_tree_insert(&encl->page_tree, PFN_DOWN(encl_page->desc),
+				encl_page);
+	if (ret)
+		goto err_out_unlock;
+
+	ret = __sgx_encl_add_page(encl, encl_page, epc_page, secinfo,
+				  src);
+	if (ret)
+		goto err_out;
+
+	/*
+	 * Complete the "add" before doing the "extend" so that the "add"
+	 * isn't in a half-baked state in the extremely unlikely scenario the
+	 * the enclave will be destroyed in response to EEXTEND failure.
+	 */
+	encl_page->encl = encl;
+	encl_page->epc_page = epc_page;
+	encl->secs_child_cnt++;
+
+	if (flags & SGX_PAGE_MEASURE) {
+		ret = __sgx_encl_extend(encl, epc_page);
+		if (ret)
+			goto err_out;
+	}
+
+	mutex_unlock(&encl->lock);
+	up_read(&current->mm->mmap_sem);
+	return ret;
+
+err_out:
+	radix_tree_delete(&encl_page->encl->page_tree,
+			  PFN_DOWN(encl_page->desc));
+
+err_out_unlock:
+	mutex_unlock(&encl->lock);
+	up_read(&current->mm->mmap_sem);
+
+err_out_free:
+	sgx_free_page(epc_page);
+	kfree(encl_page);
+
+	/*
+	 * Destroy enclave on ENCLS failure as this means that EPC has been
+	 * invalidated.
+	 */
+	if (ret == -EIO)
+		sgx_encl_destroy(encl);
+
+	return ret;
+}
+
+/**
+ * sgx_ioc_enclave_add_pages() - The handler for %SGX_IOC_ENCLAVE_ADD_PAGES
+ * @encl:       pointer to an enclave instance (via ioctl() file pointer)
+ * @arg:	a user pointer to a struct sgx_enclave_add_pages instance
+ *
+ * Add one or more pages to an uninitialized enclave, and optionally extend the
+ * measurement with the contents of the page. The address range of pages must
+ * be contiguous. The SECINFO and measurement mask are applied to all pages.
+ *
+ * A SECINFO for a TCS is required to always contain zero permissions because
+ * CPU silently zeros them. Allowing anything else would cause a mismatch in
+ * the measurement.
+ *
+ * mmap()'s protection bits are capped by the page permissions. For each page
+ * address, the maximum protection bits are computed with the following
+ * heuristics:
+ *
+ * 1. A regular page: PROT_R, PROT_W and PROT_X match the SECINFO permissions.
+ * 2. A TCS page: PROT_R | PROT_W.
+ *
+ * mmap() is not allowed to surpass the minimum of the maximum protection bits
+ * within the given address range.
+ *
+ * If ENCLS opcode fails, that effectively means that EPC has been invalidated.
+ * When this happens the enclave is destroyed and -EIO is returned to the
+ * caller.
+ *
+ * Return:
+ *   0 on success,
+ *   -EACCES if an executable source page is located in a noexec partition,
+ *   -EIO if either ENCLS[EADD] or ENCLS[EEXTEND] fails
+ *   -errno otherwise
+ */
+static long sgx_ioc_enclave_add_pages(struct sgx_encl *encl, void __user *arg)
+{
+	struct sgx_enclave_add_pages addp;
+	struct sgx_secinfo secinfo;
+	unsigned long c;
+	int ret;
+
+	if (!(atomic_read(&encl->flags) & SGX_ENCL_CREATED))
+		return -EINVAL;
+
+	if (copy_from_user(&addp, arg, sizeof(addp)))
+		return -EFAULT;
+
+	if (!IS_ALIGNED(addp.offset, PAGE_SIZE) ||
+	    !IS_ALIGNED(addp.src, PAGE_SIZE))
+		return -EINVAL;
+
+	if (!(access_ok(addp.src, PAGE_SIZE)))
+		return -EFAULT;
+
+	if (addp.length & (PAGE_SIZE - 1))
+		return -EINVAL;
+
+	if (addp.offset + addp.length - PAGE_SIZE >= encl->size)
+		return -EINVAL;
+
+	if (copy_from_user(&secinfo, (void __user *)addp.secinfo,
+			   sizeof(secinfo)))
+		return -EFAULT;
+
+	if (sgx_validate_secinfo(&secinfo))
+		return -EINVAL;
+
+	for (c = 0 ; c < addp.length; c += PAGE_SIZE) {
+		if (signal_pending(current)) {
+			ret = -EINTR;
+			break;
+		}
+
+		if (need_resched())
+			cond_resched();
+
+		ret = sgx_encl_add_page(encl, addp.src + c, addp.offset + c,
+					addp.length - c, &secinfo, addp.flags);
+		if (ret)
+			break;
+	}
+
+	addp.count = c;
+
+	if (copy_to_user(arg, &addp, sizeof(addp)))
+		return -EFAULT;
+
+	return ret;
+}
+
+static int __sgx_get_key_hash(struct crypto_shash *tfm, const void *modulus,
+			      void *hash)
+{
+	SHASH_DESC_ON_STACK(shash, tfm);
+
+	shash->tfm = tfm;
+
+	return crypto_shash_digest(shash, modulus, SGX_MODULUS_SIZE, hash);
+}
+
+static int sgx_get_key_hash(const void *modulus, void *hash)
+{
+	struct crypto_shash *tfm;
+	int ret;
+
+	tfm = crypto_alloc_shash("sha256", 0, CRYPTO_ALG_ASYNC);
+	if (IS_ERR(tfm))
+		return PTR_ERR(tfm);
+
+	ret = __sgx_get_key_hash(tfm, modulus, hash);
+
+	crypto_free_shash(tfm);
+	return ret;
+}
+
+static void sgx_update_lepubkeyhash_msrs(u64 *lepubkeyhash, bool enforce)
+{
+	u64 *cache;
+	int i;
+
+	cache = per_cpu(sgx_lepubkeyhash_cache, smp_processor_id());
+	for (i = 0; i < 4; i++) {
+		if (enforce || (lepubkeyhash[i] != cache[i])) {
+			wrmsrl(MSR_IA32_SGXLEPUBKEYHASH0 + i, lepubkeyhash[i]);
+			cache[i] = lepubkeyhash[i];
+		}
+	}
+}
+
+static int sgx_einit(struct sgx_sigstruct *sigstruct, void *token,
+		     struct sgx_epc_page *secs, u64 *lepubkeyhash)
+{
+	int ret;
+
+	preempt_disable();
+	sgx_update_lepubkeyhash_msrs(lepubkeyhash, false);
+	ret = __einit(sigstruct, token, sgx_epc_addr(secs));
+	if (ret == SGX_INVALID_EINITTOKEN) {
+		sgx_update_lepubkeyhash_msrs(lepubkeyhash, true);
+		ret = __einit(sigstruct, token, sgx_epc_addr(secs));
+	}
+	preempt_enable();
+	return ret;
+}
+
+static int sgx_encl_init(struct sgx_encl *encl, struct sgx_sigstruct *sigstruct,
+			 void *token)
+{
+	u64 mrsigner[4];
+	int ret;
+	int i;
+	int j;
+
+	/* Check that the required attributes have been authorized. */
+	if (encl->secs_attributes & ~encl->allowed_attributes)
+		return -EACCES;
+
+	ret = sgx_get_key_hash(sigstruct->modulus, mrsigner);
+	if (ret)
+		return ret;
+
+	mutex_lock(&encl->lock);
+
+	if (atomic_read(&encl->flags) & SGX_ENCL_INITIALIZED) {
+		ret = -EFAULT;
+		goto err_out;
+	}
+
+	for (i = 0; i < SGX_EINIT_SLEEP_COUNT; i++) {
+		for (j = 0; j < SGX_EINIT_SPIN_COUNT; j++) {
+			ret = sgx_einit(sigstruct, token, encl->secs.epc_page,
+					mrsigner);
+			if (ret == SGX_UNMASKED_EVENT)
+				continue;
+			else
+				break;
+		}
+
+		if (ret != SGX_UNMASKED_EVENT)
+			break;
+
+		msleep_interruptible(SGX_EINIT_SLEEP_TIME);
+
+		if (signal_pending(current)) {
+			ret = -ERESTARTSYS;
+			goto err_out;
+		}
+	}
+
+	if (ret & ENCLS_FAULT_FLAG) {
+		if (encls_failed(ret))
+			ENCLS_WARN(ret, "EINIT");
+
+		sgx_encl_destroy(encl);
+		ret = -EFAULT;
+	} else if (ret) {
+		pr_debug("EINIT returned %d\n", ret);
+		ret = -EPERM;
+	} else {
+		atomic_or(SGX_ENCL_INITIALIZED, &encl->flags);
+	}
+
+err_out:
+	mutex_unlock(&encl->lock);
+	return ret;
+}
+
+/**
+ * sgx_ioc_enclave_init - handler for %SGX_IOC_ENCLAVE_INIT
+ *
+ * @filep:	open file to /dev/sgx
+ * @arg:	userspace pointer to a struct sgx_enclave_init instance
+ *
+ * Flush any outstanding enqueued EADD operations and perform EINIT.  The
+ * Launch Enclave Public Key Hash MSRs are rewritten as necessary to match
+ * the enclave's MRSIGNER, which is caculated from the provided sigstruct.
+ *
+ * Return:
+ *   0 on success,
+ *   SGX error code on EINIT failure,
+ *   -errno otherwise
+ */
+static long sgx_ioc_enclave_init(struct sgx_encl *encl, void __user *arg)
+{
+	struct sgx_sigstruct *sigstruct;
+	struct sgx_enclave_init einit;
+	struct page *initp_page;
+	void *token;
+	int ret;
+
+	if (!(atomic_read(&encl->flags) & SGX_ENCL_CREATED))
+		return -EINVAL;
+
+	if (copy_from_user(&einit, arg, sizeof(einit)))
+		return -EFAULT;
+
+	initp_page = alloc_page(GFP_KERNEL);
+	if (!initp_page)
+		return -ENOMEM;
+
+	sigstruct = kmap(initp_page);
+	token = (void *)((unsigned long)sigstruct + PAGE_SIZE / 2);
+	memset(token, 0, SGX_LAUNCH_TOKEN_SIZE);
+
+	if (copy_from_user(sigstruct, (void __user *)einit.sigstruct,
+			   sizeof(*sigstruct))) {
+		ret = -EFAULT;
+		goto out;
+	}
+
+	ret = sgx_encl_init(encl, sigstruct, token);
+
+out:
+	kunmap(initp_page);
+	__free_page(initp_page);
+	return ret;
+}
+
+
+long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
+{
+	struct sgx_encl *encl = filep->private_data;
+	int ret, encl_flags;
+
+	encl_flags = atomic_fetch_or(SGX_ENCL_IOCTL, &encl->flags);
+	if (encl_flags & SGX_ENCL_IOCTL)
+		return -EBUSY;
+
+	if (encl_flags & SGX_ENCL_DEAD)
+		return -EFAULT;
+
+	switch (cmd) {
+	case SGX_IOC_ENCLAVE_CREATE:
+		ret = sgx_ioc_enclave_create(encl, (void __user *)arg);
+		break;
+	case SGX_IOC_ENCLAVE_ADD_PAGES:
+		ret = sgx_ioc_enclave_add_pages(encl, (void __user *)arg);
+		break;
+	case SGX_IOC_ENCLAVE_INIT:
+		ret = sgx_ioc_enclave_init(encl, (void __user *)arg);
+		break;
+	default:
+		ret = -ENOIOCTLCMD;
+		break;
+	}
+
+	atomic_andnot(SGX_ENCL_IOCTL, &encl->flags);
+
+	return ret;
+}
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 60d82e7537c8..842f9abba1c0 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -8,6 +8,7 @@
 #include <linux/ratelimit.h>
 #include <linux/sched/signal.h>
 #include <linux/slab.h>
+#include "driver.h"
 #include "encls.h"
 
 struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
@@ -193,6 +194,8 @@ static bool __init sgx_page_cache_init(void)
 
 static void __init sgx_init(void)
 {
+	int ret;
+
 	if (!boot_cpu_has(X86_FEATURE_SGX))
 		return;
 
@@ -202,10 +205,17 @@ static void __init sgx_init(void)
 	if (!sgx_page_reclaimer_init())
 		goto err_page_cache;
 
+	ret = sgx_drv_init();
+	if (ret)
+		goto err_kthread;
+
 	return;
 
+err_kthread:
+	kthread_stop(ksgxswapd_tsk);
+
 err_page_cache:
 	sgx_page_cache_teardown();
 }
 
-arch_initcall(sgx_init);
+device_initcall(sgx_init);
diff --git a/arch/x86/kernel/cpu/sgx/reclaim.c b/arch/x86/kernel/cpu/sgx/reclaim.c
index 215371588a25..9e6d3e147aa2 100644
--- a/arch/x86/kernel/cpu/sgx/reclaim.c
+++ b/arch/x86/kernel/cpu/sgx/reclaim.c
@@ -10,6 +10,7 @@
 #include <linux/sched/mm.h>
 #include <linux/sched/signal.h>
 #include "encls.h"
+#include "driver.h"
 
 struct task_struct *ksgxswapd_tsk;
 
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH v30 11/20] x86/sgx: Add provisioning
  2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
                   ` (9 preceding siblings ...)
  2020-05-15  0:44 ` [PATCH v30 10/20] x86/sgx: Linux Enclave Driver Jarkko Sakkinen
@ 2020-05-15  0:44 ` Jarkko Sakkinen
  2020-05-15  0:44 ` [PATCH v30 12/20] x86/sgx: Add a page reclaimer Jarkko Sakkinen
                   ` (9 subsequent siblings)
  20 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-15  0:44 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: akpm, dave.hansen, sean.j.christopherson, nhorman, npmccallum,
	haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp, josh, luto,
	kai.huang, rientjes, cedric.xing, puiterwijk, Jarkko Sakkinen,
	linux-security-module, Jethro Beekman


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[-- Attachment #0: Type: text/plain; charset=y, Size: 5663 bytes --]

In order to provide a mechanism for devilering provisoning rights:

1. Add a new device file /dev/sgx/provision that works as a token for
   allowing an enclave to have the provisioning privileges.
2. Add a new ioctl called SGX_IOC_ENCLAVE_SET_ATTRIBUTE that accepts the
   following data structure:

   struct sgx_enclave_set_attribute {
           __u64 addr;
           __u64 attribute_fd;
   };

A daemon could sit on top of /dev/sgx/provision and send a file
descriptor of this file to a process that needs to be able to provision
enclaves.

The way this API is used is straight-forward. Lets assume that dev_fd is
a handle to /dev/sgx/enclave and prov_fd is a handle to
/dev/sgx/provision.  You would allow SGX_IOC_ENCLAVE_CREATE to
initialize an enclave with the PROVISIONKEY attribute by

params.addr = <enclave address>;
params.token_fd = prov_fd;

ioctl(dev_fd, SGX_IOC_ENCLAVE_SET_ATTRIBUTE, &params);

Cc: linux-security-module@vger.kernel.org
Suggested-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Jethro Beekman <jethro@fortanix.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 arch/x86/include/uapi/asm/sgx.h  | 11 ++++++++
 arch/x86/kernel/cpu/sgx/driver.c | 14 ++++++++++
 arch/x86/kernel/cpu/sgx/driver.h |  2 ++
 arch/x86/kernel/cpu/sgx/ioctl.c  | 47 ++++++++++++++++++++++++++++++++
 4 files changed, 74 insertions(+)

diff --git a/arch/x86/include/uapi/asm/sgx.h b/arch/x86/include/uapi/asm/sgx.h
index 5edb08ab8fd0..57d0d30c79b3 100644
--- a/arch/x86/include/uapi/asm/sgx.h
+++ b/arch/x86/include/uapi/asm/sgx.h
@@ -25,6 +25,8 @@ enum sgx_page_flags {
 	_IOWR(SGX_MAGIC, 0x01, struct sgx_enclave_add_pages)
 #define SGX_IOC_ENCLAVE_INIT \
 	_IOW(SGX_MAGIC, 0x02, struct sgx_enclave_init)
+#define SGX_IOC_ENCLAVE_SET_ATTRIBUTE \
+	_IOW(SGX_MAGIC, 0x03, struct sgx_enclave_set_attribute)
 
 /**
  * struct sgx_enclave_create - parameter structure for the
@@ -63,4 +65,13 @@ struct sgx_enclave_init {
 	__u64 sigstruct;
 };
 
+/**
+ * struct sgx_enclave_set_attribute - parameter structure for the
+ *				      %SGX_IOC_ENCLAVE_SET_ATTRIBUTE ioctl
+ * @attribute_fd:	file handle of the attribute file in the securityfs
+ */
+struct sgx_enclave_set_attribute {
+	__u64 attribute_fd;
+};
+
 #endif /* _UAPI_ASM_X86_SGX_H */
diff --git a/arch/x86/kernel/cpu/sgx/driver.c b/arch/x86/kernel/cpu/sgx/driver.c
index b4aa7b9f8376..d90114cec1c3 100644
--- a/arch/x86/kernel/cpu/sgx/driver.c
+++ b/arch/x86/kernel/cpu/sgx/driver.c
@@ -150,6 +150,13 @@ static struct miscdevice sgx_dev_enclave = {
 	.fops = &sgx_encl_fops,
 };
 
+static struct miscdevice sgx_dev_provision = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "provision",
+	.nodename = "sgx/provision",
+	.fops = &sgx_provision_fops,
+};
+
 int __init sgx_drv_init(void)
 {
 	unsigned int eax, ebx, ecx, edx;
@@ -190,5 +197,12 @@ int __init sgx_drv_init(void)
 		return ret;
 	}
 
+	ret = misc_register(&sgx_dev_provision);
+	if (ret) {
+		pr_err("Creating /dev/sgx/provision failed with %d.\n", ret);
+		misc_deregister(&sgx_dev_enclave);
+		return ret;
+	}
+
 	return 0;
 }
diff --git a/arch/x86/kernel/cpu/sgx/driver.h b/arch/x86/kernel/cpu/sgx/driver.h
index e4063923115b..72747d01c046 100644
--- a/arch/x86/kernel/cpu/sgx/driver.h
+++ b/arch/x86/kernel/cpu/sgx/driver.h
@@ -23,6 +23,8 @@ extern u64 sgx_attributes_reserved_mask;
 extern u64 sgx_xfrm_reserved_mask;
 extern u32 sgx_xsave_size_tbl[64];
 
+extern const struct file_operations sgx_provision_fops;
+
 long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg);
 
 int sgx_drv_init(void);
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index 26d0425d7252..aea3e82a7ab9 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -653,6 +653,50 @@ static long sgx_ioc_enclave_init(struct sgx_encl *encl, void __user *arg)
 	return ret;
 }
 
+/**
+ * sgx_ioc_enclave_set_attribute - handler for %SGX_IOC_ENCLAVE_SET_ATTRIBUTE
+ * @filep:	open file to /dev/sgx
+ * @arg:	userspace pointer to a struct sgx_enclave_set_attribute instance
+ *
+ * Mark the enclave as being allowed to access a restricted attribute bit.
+ * The requested attribute is specified via the attribute_fd field in the
+ * provided struct sgx_enclave_set_attribute.  The attribute_fd must be a
+ * handle to an SGX attribute file, e.g. “/dev/sgx/provision".
+ *
+ * Failure to explicitly request access to a restricted attribute will cause
+ * sgx_ioc_enclave_init() to fail.  Currently, the only restricted attribute
+ * is access to the PROVISION_KEY.
+ *
+ * Note, access to the EINITTOKEN_KEY is disallowed entirely.
+ *
+ * Return: 0 on success, -errno otherwise
+ */
+static long sgx_ioc_enclave_set_attribute(struct sgx_encl *encl,
+					  void __user *arg)
+{
+	struct sgx_enclave_set_attribute params;
+	struct file *attribute_file;
+	int ret;
+
+	if (copy_from_user(&params, arg, sizeof(params)))
+		return -EFAULT;
+
+	attribute_file = fget(params.attribute_fd);
+	if (!attribute_file)
+		return -EINVAL;
+
+	if (attribute_file->f_op != &sgx_provision_fops) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	encl->allowed_attributes |= SGX_ATTR_PROVISIONKEY;
+	ret = 0;
+
+out:
+	fput(attribute_file);
+	return ret;
+}
 
 long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
 {
@@ -676,6 +720,9 @@ long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
 	case SGX_IOC_ENCLAVE_INIT:
 		ret = sgx_ioc_enclave_init(encl, (void __user *)arg);
 		break;
+	case SGX_IOC_ENCLAVE_SET_ATTRIBUTE:
+		ret = sgx_ioc_enclave_set_attribute(encl, (void __user *)arg);
+		break;
 	default:
 		ret = -ENOIOCTLCMD;
 		break;
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH v30 12/20] x86/sgx: Add a page reclaimer
  2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
                   ` (10 preceding siblings ...)
  2020-05-15  0:44 ` [PATCH v30 11/20] x86/sgx: Add provisioning Jarkko Sakkinen
@ 2020-05-15  0:44 ` Jarkko Sakkinen
  2020-05-22  6:58   ` Sean Christopherson
  2020-05-22  7:15   ` Sean Christopherson
  2020-05-15  0:44 ` [PATCH v30 13/20] x86/sgx: ptrace() support for the SGX driver Jarkko Sakkinen
                   ` (8 subsequent siblings)
  20 siblings, 2 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-15  0:44 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: akpm, dave.hansen, sean.j.christopherson, nhorman, npmccallum,
	haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp, josh, luto,
	kai.huang, rientjes, cedric.xing, puiterwijk, Jarkko Sakkinen,
	linux-mm, Jethro Beekman, Jordan Hand, Chunyang Hui, Seth Moore

There is a limited amount of SGX reserved memory available. Therefore,
some of it must be copied to the regular memory, and only subset kept in
the SGX reserved memory. While kernel cannot directly access enclave
memory, SGX provides ENCLS leaf functions to perform reclaiming
functionality.

This commits implements a page reclaimer by using these leaf functions,
which picks the victim pages in LRU fashion from all enclaves running in
an enclave's pages back to the SGX reserved memory.

The thread ksgxswapd reclaims pages on the event when the number of free
EPC pages goes below %SGX_NR_LOW_PAGES up until it reaches
%SGX_NR_HIGH_PAGES.

sgx_alloc_page() can now optionally reclaim pages with @reclaim boolean
parameter. The caller must also supply owner for each page so that the
reclaimer can access the associated enclaves. This is needed for locking,
as most of the ENCLS leafs cannot be executed concurrently for an enclave,
and accessing SECS, which is required to be resident when its child pages
are being reclaimed.

Cc: linux-mm@kvack.org
Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Jethro Beekman <jethro@fortanix.com>
Tested-by: Jethro Beekman <jethro@fortanix.com>
Tested-by: Jordan Hand <jorhand@linux.microsoft.com>
Tested-by: Nathaniel McCallum <npmccallum@redhat.com>
Tested-by: Chunyang Hui <sanqian.hcy@antfin.com>
Tested-by: Seth Moore <sethmo@google.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 arch/x86/kernel/cpu/sgx/driver.c  |   1 +
 arch/x86/kernel/cpu/sgx/encl.c    | 340 +++++++++++++++++++++++++-
 arch/x86/kernel/cpu/sgx/encl.h    |  41 ++++
 arch/x86/kernel/cpu/sgx/ioctl.c   |  76 +++++-
 arch/x86/kernel/cpu/sgx/main.c    |  61 ++++-
 arch/x86/kernel/cpu/sgx/reclaim.c | 388 ++++++++++++++++++++++++++++++
 arch/x86/kernel/cpu/sgx/sgx.h     |  35 +++
 7 files changed, 934 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/cpu/sgx/driver.c b/arch/x86/kernel/cpu/sgx/driver.c
index d90114cec1c3..997a7f4117c5 100644
--- a/arch/x86/kernel/cpu/sgx/driver.c
+++ b/arch/x86/kernel/cpu/sgx/driver.c
@@ -32,6 +32,7 @@ static int sgx_open(struct inode *inode, struct file *file)
 
 	atomic_set(&encl->flags, 0);
 	kref_init(&encl->refcount);
+	INIT_LIST_HEAD(&encl->va_pages);
 	INIT_RADIX_TREE(&encl->page_tree, GFP_KERNEL);
 	mutex_init(&encl->lock);
 	INIT_LIST_HEAD(&encl->mm_list);
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
index 17e44bf8fa56..fe7dbca40bb4 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -9,11 +9,86 @@
 #include <linux/sched/mm.h>
 #include "arch.h"
 #include "encl.h"
+#include "encls.h"
 #include "sgx.h"
 
+static int __sgx_encl_eldu(struct sgx_encl_page *encl_page,
+			   struct sgx_epc_page *epc_page,
+			   struct sgx_epc_page *secs_page)
+{
+	unsigned long va_offset = SGX_ENCL_PAGE_VA_OFFSET(encl_page);
+	struct sgx_encl *encl = encl_page->encl;
+	struct sgx_pageinfo pginfo;
+	struct sgx_backing b;
+	pgoff_t page_index;
+	int ret;
+
+	if (secs_page)
+		page_index = SGX_ENCL_PAGE_INDEX(encl_page);
+	else
+		page_index = PFN_DOWN(encl->size);
+
+	ret = sgx_encl_get_backing(encl, page_index, &b);
+	if (ret)
+		return ret;
+
+	pginfo.addr = SGX_ENCL_PAGE_ADDR(encl_page);
+	pginfo.contents = (unsigned long)kmap_atomic(b.contents);
+	pginfo.metadata = (unsigned long)kmap_atomic(b.pcmd) +
+			  b.pcmd_offset;
+
+	if (secs_page)
+		pginfo.secs = (u64)sgx_epc_addr(secs_page);
+	else
+		pginfo.secs = 0;
+
+	ret = __eldu(&pginfo, sgx_epc_addr(epc_page),
+		     sgx_epc_addr(encl_page->va_page->epc_page) + va_offset);
+	if (ret) {
+		if (encls_failed(ret))
+			ENCLS_WARN(ret, "ELDU");
+
+		ret = -EFAULT;
+	}
+
+	kunmap_atomic((void *)(unsigned long)(pginfo.metadata - b.pcmd_offset));
+	kunmap_atomic((void *)(unsigned long)pginfo.contents);
+
+	sgx_encl_put_backing(&b, false);
+
+	return ret;
+}
+
+static struct sgx_epc_page *sgx_encl_eldu(struct sgx_encl_page *encl_page,
+					  struct sgx_epc_page *secs_page)
+{
+	unsigned long va_offset = SGX_ENCL_PAGE_VA_OFFSET(encl_page);
+	struct sgx_encl *encl = encl_page->encl;
+	struct sgx_epc_page *epc_page;
+	int ret;
+
+	epc_page = sgx_alloc_page(encl_page, false);
+	if (IS_ERR(epc_page))
+		return epc_page;
+
+	ret = __sgx_encl_eldu(encl_page, epc_page, secs_page);
+	if (ret) {
+		sgx_free_page(epc_page);
+		return ERR_PTR(ret);
+	}
+
+	sgx_free_va_slot(encl_page->va_page, va_offset);
+	list_move(&encl_page->va_page->list, &encl->va_pages);
+	encl_page->desc &= ~SGX_ENCL_PAGE_VA_OFFSET_MASK;
+	encl_page->epc_page = epc_page;
+
+	return epc_page;
+}
+
 static struct sgx_encl_page *sgx_encl_load_page(struct sgx_encl *encl,
 						unsigned long addr)
 {
+	struct sgx_epc_page *epc_page;
 	struct sgx_encl_page *entry;
 	unsigned int flags;
 
@@ -33,10 +108,27 @@ static struct sgx_encl_page *sgx_encl_load_page(struct sgx_encl *encl,
 		return ERR_PTR(-EFAULT);
 
 	/* Page is already resident in the EPC. */
-	if (entry->epc_page)
+	if (entry->epc_page) {
+		if (entry->desc & SGX_ENCL_PAGE_RECLAIMED)
+			return ERR_PTR(-EBUSY);
+
 		return entry;
+	}
+
+	if (!(encl->secs.epc_page)) {
+		epc_page = sgx_encl_eldu(&encl->secs, NULL);
+		if (IS_ERR(epc_page))
+			return ERR_CAST(epc_page);
+	}
+
+	epc_page = sgx_encl_eldu(entry, encl->secs.epc_page);
+	if (IS_ERR(epc_page))
+		return ERR_CAST(epc_page);
 
-	return ERR_PTR(-EFAULT);
+	encl->secs_child_cnt++;
+	sgx_mark_page_reclaimable(entry->epc_page);
+
+	return entry;
 }
 
 static void sgx_mmu_notifier_release(struct mmu_notifier *mn,
@@ -134,6 +226,9 @@ int sgx_encl_mm_add(struct sgx_encl *encl, struct mm_struct *mm)
 
 	spin_lock(&encl->mm_lock);
 	list_add_rcu(&encl_mm->list, &encl->mm_list);
+	/* Pairs with smp_rmb() in sgx_reclaimer_block(). */
+	smp_wmb();
+	encl->mm_list_version++;
 	spin_unlock(&encl->mm_lock);
 
 	return 0;
@@ -181,6 +276,8 @@ static unsigned int sgx_vma_fault(struct vm_fault *vmf)
 		goto out;
 	}
 
+	sgx_encl_test_and_clear_young(vma->vm_mm, entry);
+
 out:
 	mutex_unlock(&encl->lock);
 	return ret;
@@ -280,6 +377,7 @@ int sgx_encl_find(struct mm_struct *mm, unsigned long addr,
  */
 void sgx_encl_destroy(struct sgx_encl *encl)
 {
+	struct sgx_va_page *va_page;
 	struct sgx_encl_page *entry;
 	struct radix_tree_iter iter;
 	void **slot;
@@ -290,6 +388,13 @@ void sgx_encl_destroy(struct sgx_encl *encl)
 		entry = *slot;
 
 		if (entry->epc_page) {
+			/*
+			 * The page and its radix tree entry cannot be freed
+			 * if the page is being held by the reclaimer.
+			 */
+			if (sgx_unmark_page_reclaimable(entry->epc_page))
+				continue;
+
 			sgx_free_page(entry->epc_page);
 			encl->secs_child_cnt--;
 			entry->epc_page = NULL;
@@ -304,6 +409,19 @@ void sgx_encl_destroy(struct sgx_encl *encl)
 		sgx_free_page(encl->secs.epc_page);
 		encl->secs.epc_page = NULL;
 	}
+
+	/*
+	 * The reclaimer is responsible for checking SGX_ENCL_DEAD before doing
+	 * EWB, thus it's safe to free VA pages even if the reclaimer holds a
+	 * reference to the enclave.
+	 */
+	while (!list_empty(&encl->va_pages)) {
+		va_page = list_first_entry(&encl->va_pages, struct sgx_va_page,
+					   list);
+		list_del(&va_page->list);
+		sgx_free_page(va_page->epc_page);
+		kfree(va_page);
+	}
 }
 
 /**
@@ -330,3 +448,221 @@ void sgx_encl_release(struct kref *ref)
 
 	kfree(encl);
 }
+
+static struct page *sgx_encl_get_backing_page(struct sgx_encl *encl,
+					      pgoff_t index)
+{
+	struct inode *inode = encl->backing->f_path.dentry->d_inode;
+	struct address_space *mapping = inode->i_mapping;
+	gfp_t gfpmask = mapping_gfp_mask(mapping);
+
+	return shmem_read_mapping_page_gfp(mapping, index, gfpmask);
+}
+
+/**
+ * sgx_encl_get_backing() - Pin the backing storage
+ * @encl:	an enclave
+ * @page_index:	enclave page index
+ * @backing:	data for accessing backing storage for the page
+ *
+ * Pin the backing storage pages for storing the encrypted contents and Paging
+ * Crypto MetaData (PCMD) of an enclave page.
+ *
+ * Return:
+ *   0 on success,
+ *   -errno otherwise.
+ */
+int sgx_encl_get_backing(struct sgx_encl *encl, unsigned long page_index,
+			 struct sgx_backing *backing)
+{
+	pgoff_t pcmd_index = PFN_DOWN(encl->size) + 1 + (page_index >> 5);
+	struct page *contents;
+	struct page *pcmd;
+
+	contents = sgx_encl_get_backing_page(encl, page_index);
+	if (IS_ERR(contents))
+		return PTR_ERR(contents);
+
+	pcmd = sgx_encl_get_backing_page(encl, pcmd_index);
+	if (IS_ERR(pcmd)) {
+		put_page(contents);
+		return PTR_ERR(pcmd);
+	}
+
+	backing->page_index = page_index;
+	backing->contents = contents;
+	backing->pcmd = pcmd;
+	backing->pcmd_offset =
+		(page_index & (PAGE_SIZE / sizeof(struct sgx_pcmd) - 1)) *
+		sizeof(struct sgx_pcmd);
+
+	return 0;
+}
+
+/**
+ * sgx_encl_put_backing() - Unpin the backing storage
+ * @backing:	data for accessing backing storage for the page
+ * @do_write:	mark pages dirty
+ */
+void sgx_encl_put_backing(struct sgx_backing *backing, bool do_write)
+{
+	if (do_write) {
+		set_page_dirty(backing->pcmd);
+		set_page_dirty(backing->contents);
+	}
+
+	put_page(backing->pcmd);
+	put_page(backing->contents);
+}
+
+static int sgx_encl_test_and_clear_young_cb(pte_t *ptep, unsigned long addr,
+					    void *data)
+{
+	pte_t pte;
+	int ret;
+
+	ret = pte_young(*ptep);
+	if (ret) {
+		pte = pte_mkold(*ptep);
+		set_pte_at((struct mm_struct *)data, addr, ptep, pte);
+	}
+
+	return ret;
+}
+
+/**
+ * sgx_encl_test_and_clear_young() - Test and reset the accessed bit
+ * @mm:		mm_struct that is checked
+ * @page:	enclave page to be tested for recent access
+ *
+ * Checks the Access (A) bit from the PTE corresponding to the enclave page and
+ * clears it.
+ *
+ * Return: 1 if the page has been recently accessed and 0 if not.
+ */
+int sgx_encl_test_and_clear_young(struct mm_struct *mm,
+				  struct sgx_encl_page *page)
+{
+	unsigned long addr = SGX_ENCL_PAGE_ADDR(page);
+	struct sgx_encl *encl = page->encl;
+	struct vm_area_struct *vma;
+	int ret;
+
+	ret = sgx_encl_find(mm, addr, &vma);
+	if (ret)
+		return 0;
+
+	if (encl != vma->vm_private_data)
+		return 0;
+
+	ret = apply_to_page_range(vma->vm_mm, addr, PAGE_SIZE,
+				  sgx_encl_test_and_clear_young_cb, vma->vm_mm);
+	if (ret < 0)
+		return 0;
+
+	return ret;
+}
+
+/**
+ * sgx_encl_reserve_page() - Reserve an enclave page
+ * @encl:	an enclave
+ * @addr:	a page address
+ *
+ * Load an enclave page and lock the enclave so that the page can be used by
+ * EDBG* and EMOD*.
+ *
+ * Return:
+ *   an enclave page on success
+ *   -EFAULT	if the load fails
+ */
+struct sgx_encl_page *sgx_encl_reserve_page(struct sgx_encl *encl,
+					    unsigned long addr)
+{
+	struct sgx_encl_page *entry;
+
+	for ( ; ; ) {
+		mutex_lock(&encl->lock);
+
+		entry = sgx_encl_load_page(encl, addr);
+		if (PTR_ERR(entry) != -EBUSY)
+			break;
+
+		mutex_unlock(&encl->lock);
+	}
+
+	if (IS_ERR(entry))
+		mutex_unlock(&encl->lock);
+
+	return entry;
+}
+
+/**
+ * sgx_alloc_page - allocate a VA page
+ *
+ * Allocates an &sgx_epc_page instance and converts it to a VA page.
+ *
+ * Return:
+ *   a &struct sgx_va_page instance,
+ *   -errno otherwise
+ */
+struct sgx_epc_page *sgx_alloc_va_page(void)
+{
+	struct sgx_epc_page *epc_page;
+	int ret;
+
+	epc_page = sgx_alloc_page(NULL, true);
+	if (IS_ERR(epc_page))
+		return ERR_CAST(epc_page);
+
+	ret = __epa(sgx_epc_addr(epc_page));
+	if (ret) {
+		WARN_ONCE(1, "EPA returned %d (0x%x)", ret, ret);
+		sgx_free_page(epc_page);
+		return ERR_PTR(-EFAULT);
+	}
+
+	return epc_page;
+}
+
+/**
+ * sgx_alloc_va_slot - allocate a VA slot
+ * @va_page:	a &struct sgx_va_page instance
+ *
+ * Allocates a slot from a &struct sgx_va_page instance.
+ *
+ * Return: offset of the slot inside the VA page
+ */
+unsigned int sgx_alloc_va_slot(struct sgx_va_page *va_page)
+{
+	int slot = find_first_zero_bit(va_page->slots, SGX_VA_SLOT_COUNT);
+
+	if (slot < SGX_VA_SLOT_COUNT)
+		set_bit(slot, va_page->slots);
+
+	return slot << 3;
+}
+
+/**
+ * sgx_free_va_slot - free a VA slot
+ * @va_page:	a &struct sgx_va_page instance
+ * @offset:	offset of the slot inside the VA page
+ *
+ * Frees a slot from a &struct sgx_va_page instance.
+ */
+void sgx_free_va_slot(struct sgx_va_page *va_page, unsigned int offset)
+{
+	clear_bit(offset >> 3, va_page->slots);
+}
+
+/**
+ * sgx_va_page_full - is the VA page full?
+ * @va_page:	a &struct sgx_va_page instance
+ *
+ * Return: true if all slots have been taken
+ */
+bool sgx_va_page_full(struct sgx_va_page *va_page)
+{
+	int slot = find_first_zero_bit(va_page->slots, SGX_VA_SLOT_COUNT);
+
+	return slot == SGX_VA_SLOT_COUNT;
+}
diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h
index 1d1bc5d590ee..f0f72e591244 100644
--- a/arch/x86/kernel/cpu/sgx/encl.h
+++ b/arch/x86/kernel/cpu/sgx/encl.h
@@ -19,6 +19,10 @@
 
 /**
  * enum sgx_encl_page_desc - defines bits for an enclave page's descriptor
+ * %SGX_ENCL_PAGE_RECLAIMED:		The page is in the process of being
+ *					reclaimed.
+ * %SGX_ENCL_PAGE_VA_OFFSET_MASK:	Holds the offset in the Version Array
+ *					(VA) page for a swapped page.
  * %SGX_ENCL_PAGE_ADDR_MASK:		Holds the virtual address of the page.
  *
  * The page address for SECS is zero and is used by the subsystem to recognize
@@ -26,16 +30,23 @@
  */
 enum sgx_encl_page_desc {
 	/* Bits 11:3 are available when the page is not swapped. */
+	SGX_ENCL_PAGE_RECLAIMED		= BIT(3),
+	SGX_ENCL_PAGE_VA_OFFSET_MASK	= GENMASK_ULL(11, 3),
 	SGX_ENCL_PAGE_ADDR_MASK		= PAGE_MASK,
 };
 
 #define SGX_ENCL_PAGE_ADDR(page) \
 	((page)->desc & SGX_ENCL_PAGE_ADDR_MASK)
+#define SGX_ENCL_PAGE_VA_OFFSET(page) \
+	((page)->desc & SGX_ENCL_PAGE_VA_OFFSET_MASK)
+#define SGX_ENCL_PAGE_INDEX(page) \
+	PFN_DOWN((page)->desc - (page)->encl->base)
 
 struct sgx_encl_page {
 	unsigned long desc;
 	unsigned long vm_max_prot_bits;
 	struct sgx_epc_page *epc_page;
+	struct sgx_va_page *va_page;
 	struct sgx_encl *encl;
 };
 
@@ -63,17 +74,27 @@ struct sgx_encl {
 	struct mutex lock;
 	struct list_head mm_list;
 	spinlock_t mm_lock;
+	unsigned long mm_list_version;
 	struct file *backing;
 	struct kref refcount;
 	struct srcu_struct srcu;
 	unsigned long base;
 	unsigned long size;
 	unsigned long ssaframesize;
+	struct list_head va_pages;
 	struct radix_tree_root page_tree;
 	struct sgx_encl_page secs;
 	cpumask_t cpumask;
 };
 
+#define SGX_VA_SLOT_COUNT 512
+
+struct sgx_va_page {
+	struct sgx_epc_page *epc_page;
+	DECLARE_BITMAP(slots, SGX_VA_SLOT_COUNT);
+	struct list_head list;
+};
+
 extern const struct vm_operations_struct sgx_vm_ops;
 
 int sgx_encl_find(struct mm_struct *mm, unsigned long addr,
@@ -84,4 +105,24 @@ int sgx_encl_mm_add(struct sgx_encl *encl, struct mm_struct *mm);
 int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start,
 		     unsigned long end, unsigned long vm_prot_bits);
 
+struct sgx_backing {
+	pgoff_t page_index;
+	struct page *contents;
+	struct page *pcmd;
+	unsigned long pcmd_offset;
+};
+
+int sgx_encl_get_backing(struct sgx_encl *encl, unsigned long page_index,
+			 struct sgx_backing *backing);
+void sgx_encl_put_backing(struct sgx_backing *backing, bool do_write);
+int sgx_encl_test_and_clear_young(struct mm_struct *mm,
+				  struct sgx_encl_page *page);
+struct sgx_encl_page *sgx_encl_reserve_page(struct sgx_encl *encl,
+					    unsigned long addr);
+
+struct sgx_epc_page *sgx_alloc_va_page(void);
+unsigned int sgx_alloc_va_slot(struct sgx_va_page *va_page);
+void sgx_free_va_slot(struct sgx_va_page *va_page, unsigned int offset);
+bool sgx_va_page_full(struct sgx_va_page *va_page);
+
 #endif /* _X86_ENCL_H */
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index aea3e82a7ab9..3af0596530a8 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -19,6 +19,43 @@
 /* A per-cpu cache for the last known values of IA32_SGXLEPUBKEYHASHx MSRs. */
 static DEFINE_PER_CPU(u64 [4], sgx_lepubkeyhash_cache);
 
+static struct sgx_va_page *sgx_encl_grow(struct sgx_encl *encl)
+{
+	struct sgx_va_page *va_page = NULL;
+	void *err;
+
+	BUILD_BUG_ON(SGX_VA_SLOT_COUNT !=
+		(SGX_ENCL_PAGE_VA_OFFSET_MASK >> 3) + 1);
+
+	if (!(encl->page_cnt % SGX_VA_SLOT_COUNT)) {
+		va_page = kzalloc(sizeof(*va_page), GFP_KERNEL);
+		if (!va_page)
+			return ERR_PTR(-ENOMEM);
+
+		va_page->epc_page = sgx_alloc_va_page();
+		if (IS_ERR(va_page->epc_page)) {
+			err = ERR_CAST(va_page->epc_page);
+			kfree(va_page);
+			return err;
+		}
+
+		WARN_ON_ONCE(encl->page_cnt % SGX_VA_SLOT_COUNT);
+	}
+	encl->page_cnt++;
+	return va_page;
+}
+
+static void sgx_encl_shrink(struct sgx_encl *encl, struct sgx_va_page *va_page)
+{
+	encl->page_cnt--;
+
+	if (va_page) {
+		sgx_free_page(va_page->epc_page);
+		list_del(&va_page->list);
+		kfree(va_page);
+	}
+}
+
 static u32 sgx_calc_ssaframesize(u32 miscselect, u64 xfrm)
 {
 	u32 size_max = PAGE_SIZE;
@@ -114,6 +151,7 @@ static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
 {
 	unsigned long encl_size = secs->size + PAGE_SIZE;
 	struct sgx_epc_page *secs_epc;
+	struct sgx_va_page *va_page;
 	unsigned long ssaframesize;
 	struct sgx_pageinfo pginfo;
 	struct sgx_secinfo secinfo;
@@ -123,20 +161,29 @@ static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
 	if (atomic_read(&encl->flags) & SGX_ENCL_CREATED)
 		return -EINVAL;
 
+	va_page = sgx_encl_grow(encl);
+	if (IS_ERR(va_page))
+		return PTR_ERR(va_page);
+	else if (va_page)
+		list_add(&va_page->list, &encl->va_pages);
+
 	ssaframesize = sgx_calc_ssaframesize(secs->miscselect, secs->xfrm);
 	if (sgx_validate_secs(secs, ssaframesize)) {
 		pr_debug("invalid SECS\n");
-		return -EINVAL;
+		ret = -EINVAL;
+		goto err_out_shrink;
 	}
 
 	backing = shmem_file_setup("SGX backing", encl_size + (encl_size >> 5),
 				   VM_NORESERVE);
-	if (IS_ERR(backing))
-		return PTR_ERR(backing);
+	if (IS_ERR(backing)) {
+		ret = PTR_ERR(backing);
+		goto err_out_shrink;
+	}
 
 	encl->backing = backing;
 
-	secs_epc = sgx_try_alloc_page();
+	secs_epc = sgx_alloc_page(&encl->secs, true);
 	if (IS_ERR(secs_epc)) {
 		ret = PTR_ERR(secs_epc);
 		goto err_out_backing;
@@ -183,6 +230,9 @@ static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
 	fput(encl->backing);
 	encl->backing = NULL;
 
+err_out_shrink:
+	sgx_encl_shrink(encl, va_page);
+
 	return ret;
 }
 
@@ -319,13 +369,14 @@ static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long src,
 {
 	struct sgx_encl_page *encl_page;
 	struct sgx_epc_page *epc_page;
+	struct sgx_va_page *va_page;
 	int ret;
 
 	encl_page = sgx_encl_page_alloc(encl, offset, secinfo->flags);
 	if (IS_ERR(encl_page))
 		return PTR_ERR(encl_page);
 
-	epc_page = sgx_try_alloc_page();
+	epc_page = sgx_alloc_page(encl_page, true);
 	if (IS_ERR(epc_page)) {
 		kfree(encl_page);
 		return PTR_ERR(epc_page);
@@ -337,9 +388,22 @@ static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long src,
 		goto err_out_free;
 	}
 
+	va_page = sgx_encl_grow(encl);
+	if (IS_ERR(va_page)) {
+		ret = PTR_ERR(va_page);
+		goto err_out_free;
+	}
+
 	down_read(&current->mm->mmap_sem);
 	mutex_lock(&encl->lock);
 
+	/*
+	 * Adding to encl->va_pages must be done under encl->lock.  Ditto for
+	 * deleting (via sgx_encl_shrink()) in the error path.
+	 */
+	if (va_page)
+		list_add(&va_page->list, &encl->va_pages);
+
 	/*
 	 * Insert prior to EADD in case of OOM.  EADD modifies MRENCLAVE, i.e.
 	 * can't be gracefully unwound, while failure on EADD/EXTEND is limited
@@ -370,6 +434,7 @@ static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long src,
 			goto err_out;
 	}
 
+	sgx_mark_page_reclaimable(encl_page->epc_page);
 	mutex_unlock(&encl->lock);
 	up_read(&current->mm->mmap_sem);
 	return ret;
@@ -379,6 +444,7 @@ static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long src,
 			  PFN_DOWN(encl_page->desc));
 
 err_out_unlock:
+	sgx_encl_shrink(encl, va_page);
 	mutex_unlock(&encl->lock);
 	up_read(&current->mm->mmap_sem);
 
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 842f9abba1c0..5ce77e554676 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -23,6 +23,8 @@ static struct sgx_epc_page *__sgx_try_alloc_page(struct sgx_epc_section *section
 
 	page = list_first_entry(&section->page_list, struct sgx_epc_page, list);
 	list_del_init(&page->list);
+	section->free_cnt--;
+
 	return page;
 }
 
@@ -54,23 +56,79 @@ struct sgx_epc_page *sgx_try_alloc_page(void)
 	return ERR_PTR(-ENOMEM);
 }
 
+/**
+ * sgx_alloc_page() - Allocate an EPC page
+ * @owner:	the owner of the EPC page
+ * @reclaim:	reclaim pages if necessary
+ *
+ * Try to grab a page from the free EPC page list. If there is a free page
+ * available, it is returned to the caller. The @reclaim parameter hints
+ * the EPC memory manager to swap pages when required.
+ *
+ * Return:
+ *   a pointer to a &struct sgx_epc_page instance,
+ *   -errno on error
+ */
+struct sgx_epc_page *sgx_alloc_page(void *owner, bool reclaim)
+{
+	struct sgx_epc_page *entry;
+
+	for ( ; ; ) {
+		entry = sgx_try_alloc_page();
+		if (!IS_ERR(entry)) {
+			entry->owner = owner;
+			break;
+		}
+
+		if (list_empty(&sgx_active_page_list))
+			return ERR_PTR(-ENOMEM);
+
+		if (!reclaim) {
+			entry = ERR_PTR(-EBUSY);
+			break;
+		}
+
+		if (signal_pending(current)) {
+			entry = ERR_PTR(-ERESTARTSYS);
+			break;
+		}
+
+		sgx_reclaim_pages();
+		schedule();
+	}
+
+	if (sgx_should_reclaim(SGX_NR_LOW_PAGES))
+		wake_up(&ksgxswapd_waitq);
+
+	return entry;
+}
+
 /**
  * sgx_free_page() - Free an EPC page
  * @page:	pointer a previously allocated EPC page
  *
- * EREMOVE an EPC page and insert it back to the list of free pages.
+ * EREMOVE an EPC page and insert it back to the list of free pages. The page
+ * must not be reclaimable.
  */
 void sgx_free_page(struct sgx_epc_page *page)
 {
 	struct sgx_epc_section *section = sgx_epc_section(page);
 	int ret;
 
+	/*
+	 * Don't take sgx_active_page_list_lock when asserting the page isn't
+	 * reclaimable, missing a WARN in the very rare case is preferable to
+	 * unnecessarily taking a global lock in the common case.
+	 */
+	WARN_ON_ONCE(page->desc & SGX_EPC_PAGE_RECLAIMABLE);
+
 	ret = __eremove(sgx_epc_addr(page));
 	if (WARN_ONCE(ret, "EREMOVE returned %d (0x%x)", ret, ret))
 		return;
 
 	spin_lock(&section->lock);
 	list_add_tail(&page->list, &section->page_list);
+	section->free_cnt++;
 	spin_unlock(&section->lock);
 }
 
@@ -121,6 +179,7 @@ static bool __init sgx_alloc_epc_section(u64 addr, u64 size,
 		list_add_tail(&page->list, &section->unsanitized_page_list);
 	}
 
+	section->free_cnt = nr_pages;
 	return true;
 
 err_out:
diff --git a/arch/x86/kernel/cpu/sgx/reclaim.c b/arch/x86/kernel/cpu/sgx/reclaim.c
index 9e6d3e147aa2..fb521f314fb7 100644
--- a/arch/x86/kernel/cpu/sgx/reclaim.c
+++ b/arch/x86/kernel/cpu/sgx/reclaim.c
@@ -9,10 +9,14 @@
 #include <linux/slab.h>
 #include <linux/sched/mm.h>
 #include <linux/sched/signal.h>
+#include "encl.h"
 #include "encls.h"
 #include "driver.h"
 
 struct task_struct *ksgxswapd_tsk;
+DECLARE_WAIT_QUEUE_HEAD(ksgxswapd_waitq);
+LIST_HEAD(sgx_active_page_list);
+DEFINE_SPINLOCK(sgx_active_page_list_lock);
 
 static void sgx_sanitize_section(struct sgx_epc_section *section)
 {
@@ -66,6 +70,20 @@ static int ksgxswapd(void *p)
 			WARN(1, "EPC section %d has unsanitized pages.\n", i);
 	}
 
+	while (!kthread_should_stop()) {
+		if (try_to_freeze())
+			continue;
+
+		wait_event_freezable(ksgxswapd_waitq,
+				     kthread_should_stop() ||
+				     sgx_should_reclaim(SGX_NR_HIGH_PAGES));
+
+		if (sgx_should_reclaim(SGX_NR_HIGH_PAGES))
+			sgx_reclaim_pages();
+
+		cond_resched();
+	}
+
 	return 0;
 }
 
@@ -81,3 +99,373 @@ bool __init sgx_page_reclaimer_init(void)
 
 	return true;
 }
+
+/**
+ * sgx_mark_page_reclaimable() - Mark a page as reclaimable
+ * @page:	EPC page
+ *
+ * Mark a page as reclaimable and add it to the active page list. Pages
+ * are automatically removed from the active list when freed.
+ */
+void sgx_mark_page_reclaimable(struct sgx_epc_page *page)
+{
+	spin_lock(&sgx_active_page_list_lock);
+	page->desc |= SGX_EPC_PAGE_RECLAIMABLE;
+	list_add_tail(&page->list, &sgx_active_page_list);
+	spin_unlock(&sgx_active_page_list_lock);
+}
+
+/**
+ * sgx_unmark_page_reclaimable() - Remove a page from the reclaim list
+ * @page:	EPC page
+ *
+ * Clear the reclaimable flag and remove the page from the active page list.
+ *
+ * Return:
+ *   0 on success,
+ *   -EBUSY if the page is in the process of being reclaimed
+ */
+int sgx_unmark_page_reclaimable(struct sgx_epc_page *page)
+{
+	/*
+	 * Remove the page from the active list if necessary.  If the page
+	 * is actively being reclaimed, i.e. RECLAIMABLE is set but the
+	 * page isn't on the active list, return -EBUSY as we can't free
+	 * the page at this time since it is "owned" by the reclaimer.
+	 */
+	spin_lock(&sgx_active_page_list_lock);
+	if (page->desc & SGX_EPC_PAGE_RECLAIMABLE) {
+		if (list_empty(&page->list)) {
+			spin_unlock(&sgx_active_page_list_lock);
+			return -EBUSY;
+		}
+		list_del(&page->list);
+		page->desc &= ~SGX_EPC_PAGE_RECLAIMABLE;
+	}
+	spin_unlock(&sgx_active_page_list_lock);
+
+	return 0;
+}
+
+static bool sgx_reclaimer_age(struct sgx_epc_page *epc_page)
+{
+	struct sgx_encl_page *page = epc_page->owner;
+	struct sgx_encl *encl = page->encl;
+	struct sgx_encl_mm *encl_mm;
+	bool ret = true;
+	int idx;
+
+	idx = srcu_read_lock(&encl->srcu);
+
+	list_for_each_entry_rcu(encl_mm, &encl->mm_list, list) {
+		if (!mmget_not_zero(encl_mm->mm))
+			continue;
+
+		down_read(&encl_mm->mm->mmap_sem);
+		ret = !sgx_encl_test_and_clear_young(encl_mm->mm, page);
+		up_read(&encl_mm->mm->mmap_sem);
+
+		mmput_async(encl_mm->mm);
+
+		if (!ret || (atomic_read(&encl->flags) & SGX_ENCL_DEAD))
+			break;
+	}
+
+	srcu_read_unlock(&encl->srcu, idx);
+
+	if (!ret && !(atomic_read(&encl->flags) & SGX_ENCL_DEAD))
+		return false;
+
+	return true;
+}
+
+static void sgx_reclaimer_block(struct sgx_epc_page *epc_page)
+{
+	struct sgx_encl_page *page = epc_page->owner;
+	unsigned long addr = SGX_ENCL_PAGE_ADDR(page);
+	struct sgx_encl *encl = page->encl;
+	unsigned long mm_list_version;
+	struct sgx_encl_mm *encl_mm;
+	struct vm_area_struct *vma;
+	int idx, ret;
+
+	do {
+		mm_list_version = encl->mm_list_version;
+
+		/* Pairs with smp_rmb() in sgx_encl_mm_add(). */
+		smp_rmb();
+
+		idx = srcu_read_lock(&encl->srcu);
+
+		list_for_each_entry_rcu(encl_mm, &encl->mm_list, list) {
+			if (!mmget_not_zero(encl_mm->mm))
+				continue;
+
+			down_read(&encl_mm->mm->mmap_sem);
+
+			ret = sgx_encl_find(encl_mm->mm, addr, &vma);
+			if (!ret && encl == vma->vm_private_data)
+				zap_vma_ptes(vma, addr, PAGE_SIZE);
+
+			up_read(&encl_mm->mm->mmap_sem);
+
+			mmput_async(encl_mm->mm);
+		}
+
+		srcu_read_unlock(&encl->srcu, idx);
+	} while (unlikely(encl->mm_list_version != mm_list_version));
+
+	mutex_lock(&encl->lock);
+
+	if (!(atomic_read(&encl->flags) & SGX_ENCL_DEAD)) {
+		ret = __eblock(sgx_epc_addr(epc_page));
+		if (encls_failed(ret))
+			ENCLS_WARN(ret, "EBLOCK");
+	}
+
+	mutex_unlock(&encl->lock);
+}
+
+static int __sgx_encl_ewb(struct sgx_epc_page *epc_page, void *va_slot,
+			  struct sgx_backing *backing)
+{
+	struct sgx_pageinfo pginfo;
+	int ret;
+
+	pginfo.addr = 0;
+	pginfo.secs = 0;
+
+	pginfo.contents = (unsigned long)kmap_atomic(backing->contents);
+	pginfo.metadata = (unsigned long)kmap_atomic(backing->pcmd) +
+			  backing->pcmd_offset;
+
+	ret = __ewb(&pginfo, sgx_epc_addr(epc_page), va_slot);
+
+	kunmap_atomic((void *)(unsigned long)(pginfo.metadata -
+					      backing->pcmd_offset));
+	kunmap_atomic((void *)(unsigned long)pginfo.contents);
+
+	return ret;
+}
+
+static void sgx_ipi_cb(void *info)
+{
+}
+
+static const cpumask_t *sgx_encl_ewb_cpumask(struct sgx_encl *encl)
+{
+	cpumask_t *cpumask = &encl->cpumask;
+	struct sgx_encl_mm *encl_mm;
+	int idx;
+
+	/*
+	 * Can race with sgx_encl_mm_add(), but ETRACK has already been
+	 * executed, which means that the CPUs running in the new mm will enter
+	 * into the enclave with a fresh epoch.
+	 */
+	cpumask_clear(cpumask);
+
+	idx = srcu_read_lock(&encl->srcu);
+
+	list_for_each_entry_rcu(encl_mm, &encl->mm_list, list) {
+		if (!mmget_not_zero(encl_mm->mm))
+			continue;
+
+		cpumask_or(cpumask, cpumask, mm_cpumask(encl_mm->mm));
+
+		mmput_async(encl_mm->mm);
+	}
+
+	srcu_read_unlock(&encl->srcu, idx);
+
+	return cpumask;
+}
+
+static void sgx_encl_ewb(struct sgx_epc_page *epc_page,
+			 struct sgx_backing *backing)
+{
+	struct sgx_encl_page *encl_page = epc_page->owner;
+	struct sgx_encl *encl = encl_page->encl;
+	struct sgx_va_page *va_page;
+	unsigned int va_offset;
+	void *va_slot;
+	int ret;
+
+	encl_page->desc &= ~SGX_ENCL_PAGE_RECLAIMED;
+
+	va_page = list_first_entry(&encl->va_pages, struct sgx_va_page,
+				   list);
+	va_offset = sgx_alloc_va_slot(va_page);
+	va_slot = sgx_epc_addr(va_page->epc_page) + va_offset;
+	if (sgx_va_page_full(va_page))
+		list_move_tail(&va_page->list, &encl->va_pages);
+
+	ret = __sgx_encl_ewb(epc_page, va_slot, backing);
+	if (ret == SGX_NOT_TRACKED) {
+		ret = __etrack(sgx_epc_addr(encl->secs.epc_page));
+		if (ret) {
+			if (encls_failed(ret))
+				ENCLS_WARN(ret, "ETRACK");
+		}
+
+		ret = __sgx_encl_ewb(epc_page, va_slot, backing);
+		if (ret == SGX_NOT_TRACKED) {
+			/*
+			 * Slow path, send IPIs to kick cpus out of the
+			 * enclave.  Note, it's imperative that the cpu
+			 * mask is generated *after* ETRACK, else we'll
+			 * miss cpus that entered the enclave between
+			 * generating the mask and incrementing epoch.
+			 */
+			on_each_cpu_mask(sgx_encl_ewb_cpumask(encl),
+					 sgx_ipi_cb, NULL, 1);
+			ret = __sgx_encl_ewb(epc_page, va_slot, backing);
+		}
+	}
+
+	if (ret) {
+		if (encls_failed(ret))
+			ENCLS_WARN(ret, "EWB");
+
+		sgx_free_va_slot(va_page, va_offset);
+	} else {
+		encl_page->desc |= va_offset;
+		encl_page->va_page = va_page;
+	}
+}
+
+static void sgx_reclaimer_write(struct sgx_epc_page *epc_page,
+				struct sgx_backing *backing)
+{
+	struct sgx_encl_page *encl_page = epc_page->owner;
+	struct sgx_encl *encl = encl_page->encl;
+	struct sgx_backing secs_backing;
+	int ret;
+
+	mutex_lock(&encl->lock);
+
+	if (atomic_read(&encl->flags) & SGX_ENCL_DEAD) {
+		ret = __eremove(sgx_epc_addr(epc_page));
+		ENCLS_WARN(ret, "EREMOVE returned %d\n");
+	} else {
+		sgx_encl_ewb(epc_page, backing);
+	}
+
+	encl_page->epc_page = NULL;
+	encl->secs_child_cnt--;
+
+	if (!encl->secs_child_cnt) {
+		if (atomic_read(&encl->flags) & SGX_ENCL_DEAD) {
+			sgx_free_page(encl->secs.epc_page);
+			encl->secs.epc_page = NULL;
+		} else if (atomic_read(&encl->flags) & SGX_ENCL_INITIALIZED) {
+			ret = sgx_encl_get_backing(encl, PFN_DOWN(encl->size),
+						   &secs_backing);
+			if (ret)
+				goto out;
+
+			sgx_encl_ewb(encl->secs.epc_page, &secs_backing);
+
+			sgx_free_page(encl->secs.epc_page);
+			encl->secs.epc_page = NULL;
+
+			sgx_encl_put_backing(&secs_backing, true);
+		}
+	}
+
+out:
+	mutex_unlock(&encl->lock);
+}
+
+/**
+ * sgx_reclaim_pages() - Reclaim EPC pages from the consumers
+ *
+ * Take a fixed number of pages from the head of the active page pool and
+ * reclaim them to the enclave's private shmem files. Skip the pages, which
+ * have been accessed since the last scan. Move those pages to the tail of
+ * active page pool so that the pages get scanned in LRU like fashion.
+ */
+void sgx_reclaim_pages(void)
+{
+	struct sgx_epc_page *chunk[SGX_NR_TO_SCAN];
+	struct sgx_backing backing[SGX_NR_TO_SCAN];
+	struct sgx_epc_section *section;
+	struct sgx_encl_page *encl_page;
+	struct sgx_epc_page *epc_page;
+	int cnt = 0;
+	int ret;
+	int i;
+
+	spin_lock(&sgx_active_page_list_lock);
+	for (i = 0; i < SGX_NR_TO_SCAN; i++) {
+		if (list_empty(&sgx_active_page_list))
+			break;
+
+		epc_page = list_first_entry(&sgx_active_page_list,
+					    struct sgx_epc_page, list);
+		list_del_init(&epc_page->list);
+		encl_page = epc_page->owner;
+
+		if (kref_get_unless_zero(&encl_page->encl->refcount) != 0)
+			chunk[cnt++] = epc_page;
+		else
+			/* The owner is freeing the page. No need to add the
+			 * page back to the list of reclaimable pages.
+			 */
+			epc_page->desc &= ~SGX_EPC_PAGE_RECLAIMABLE;
+	}
+	spin_unlock(&sgx_active_page_list_lock);
+
+	for (i = 0; i < cnt; i++) {
+		epc_page = chunk[i];
+		encl_page = epc_page->owner;
+
+		if (!sgx_reclaimer_age(epc_page))
+			goto skip;
+
+		ret = sgx_encl_get_backing(encl_page->encl,
+					   SGX_ENCL_PAGE_INDEX(encl_page),
+					   &backing[i]);
+		if (ret)
+			goto skip;
+
+		mutex_lock(&encl_page->encl->lock);
+		encl_page->desc |= SGX_ENCL_PAGE_RECLAIMED;
+		mutex_unlock(&encl_page->encl->lock);
+		continue;
+
+skip:
+		kref_put(&encl_page->encl->refcount, sgx_encl_release);
+
+		spin_lock(&sgx_active_page_list_lock);
+		list_add_tail(&epc_page->list, &sgx_active_page_list);
+		spin_unlock(&sgx_active_page_list_lock);
+
+		chunk[i] = NULL;
+	}
+
+	for (i = 0; i < cnt; i++) {
+		epc_page = chunk[i];
+		if (epc_page)
+			sgx_reclaimer_block(epc_page);
+	}
+
+	for (i = 0; i < cnt; i++) {
+		epc_page = chunk[i];
+		if (!epc_page)
+			continue;
+
+		encl_page = epc_page->owner;
+		sgx_reclaimer_write(epc_page, &backing[i]);
+		sgx_encl_put_backing(&backing[i], true);
+
+		kref_put(&encl_page->encl->refcount, sgx_encl_release);
+		epc_page->desc &= ~SGX_EPC_PAGE_RECLAIMABLE;
+
+		section = sgx_epc_section(epc_page);
+		spin_lock(&section->lock);
+		list_add_tail(&epc_page->list, &section->page_list);
+		section->free_cnt++;
+		spin_unlock(&section->lock);
+	}
+}
diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h
index aa85f85412d8..0c481e6f2c95 100644
--- a/arch/x86/kernel/cpu/sgx/sgx.h
+++ b/arch/x86/kernel/cpu/sgx/sgx.h
@@ -15,6 +15,7 @@
 
 struct sgx_epc_page {
 	unsigned long desc;
+	struct sgx_encl_page *owner;
 	struct list_head list;
 };
 
@@ -29,6 +30,7 @@ struct sgx_epc_page {
 struct sgx_epc_section {
 	unsigned long pa;
 	void *va;
+	unsigned long free_cnt;
 	struct list_head page_list;
 	struct list_head unsanitized_page_list;
 	spinlock_t lock;
@@ -40,9 +42,14 @@ struct sgx_epc_section {
  *				physical memory. The existing and near-future
  *				hardware defines at most eight sections, hence
  *				three bits to hold a section.
+ * %SGX_EPC_PAGE_RECLAIMABLE:	The page has been been marked as reclaimable.
+ *				Pages need to be colored this way because a page
+ *				can be out of the active page list in the
+ *				process of being swapped out.
  */
 enum sgx_epc_page_desc {
 	SGX_EPC_SECTION_MASK			= GENMASK_ULL(3, 0),
+	SGX_EPC_PAGE_RECLAIMABLE		= BIT(4),
 	/* bits 12-63 are reserved for the physical page address of the page */
 };
 
@@ -62,12 +69,40 @@ static inline void *sgx_epc_addr(struct sgx_epc_page *page)
 	return section->va + (page->desc & PAGE_MASK) - section->pa;
 }
 
+#define SGX_NR_TO_SCAN		16
+#define SGX_NR_LOW_PAGES	32
+#define SGX_NR_HIGH_PAGES	64
+
 extern int sgx_nr_epc_sections;
 extern struct task_struct *ksgxswapd_tsk;
+extern struct wait_queue_head(ksgxswapd_waitq);
+extern struct list_head sgx_active_page_list;
+extern spinlock_t sgx_active_page_list_lock;
+
+static inline unsigned long sgx_nr_free_pages(void)
+{
+	unsigned long cnt = 0;
+	int i;
+
+	for (i = 0; i < sgx_nr_epc_sections; i++)
+		cnt += sgx_epc_sections[i].free_cnt;
+
+	return cnt;
+}
+
+static inline bool sgx_should_reclaim(unsigned long watermark)
+{
+	return sgx_nr_free_pages() < watermark &&
+	       !list_empty(&sgx_active_page_list);
+}
 
 bool __init sgx_page_reclaimer_init(void);
+void sgx_mark_page_reclaimable(struct sgx_epc_page *page);
+int sgx_unmark_page_reclaimable(struct sgx_epc_page *page);
+void sgx_reclaim_pages(void);
 
 struct sgx_epc_page *sgx_try_alloc_page(void);
+struct sgx_epc_page *sgx_alloc_page(void *owner, bool reclaim);
 void sgx_free_page(struct sgx_epc_page *page);
 
 #endif /* _X86_SGX_H */
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH v30 13/20] x86/sgx: ptrace() support for the SGX driver
  2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
                   ` (11 preceding siblings ...)
  2020-05-15  0:44 ` [PATCH v30 12/20] x86/sgx: Add a page reclaimer Jarkko Sakkinen
@ 2020-05-15  0:44 ` Jarkko Sakkinen
  2020-05-15  0:44 ` [PATCH v30 14/20] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
                   ` (7 subsequent siblings)
  20 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-15  0:44 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: akpm, dave.hansen, sean.j.christopherson, nhorman, npmccallum,
	haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp, josh, luto,
	kai.huang, rientjes, cedric.xing, puiterwijk, Jarkko Sakkinen,
	Jethro Beekman

Add VMA callbacks for ptrace() that can be used with debug enclaves.
With debug enclaves data can be read and write the memory word at a time
by using ENCLS(EDBGRD) and ENCLS(EDBGWR) leaf instructions.

Acked-by: Jethro Beekman <jethro@fortanix.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 arch/x86/kernel/cpu/sgx/encl.c | 87 ++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)

diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
index fe7dbca40bb4..2211e86fb711 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -333,10 +333,97 @@ static int sgx_vma_mprotect(struct vm_area_struct *vma, unsigned long start,
 				calc_vm_prot_bits(prot, 0));
 }
 
+static int sgx_edbgrd(struct sgx_encl *encl, struct sgx_encl_page *page,
+		      unsigned long addr, void *data)
+{
+	unsigned long offset = addr & ~PAGE_MASK;
+	int ret;
+
+
+	ret = __edbgrd(sgx_epc_addr(page->epc_page) + offset, data);
+	if (ret)
+		return -EIO;
+
+	return 0;
+}
+
+static int sgx_edbgwr(struct sgx_encl *encl, struct sgx_encl_page *page,
+		      unsigned long addr, void *data)
+{
+	unsigned long offset = addr & ~PAGE_MASK;
+	int ret;
+
+	ret = __edbgwr(sgx_epc_addr(page->epc_page) + offset, data);
+	if (ret)
+		return -EIO;
+
+	return 0;
+}
+
+static int sgx_vma_access(struct vm_area_struct *vma, unsigned long addr,
+			  void *buf, int len, int write)
+{
+	struct sgx_encl *encl = vma->vm_private_data;
+	struct sgx_encl_page *entry = NULL;
+	char data[sizeof(unsigned long)];
+	unsigned long align;
+	unsigned int flags;
+	int offset;
+	int cnt;
+	int ret = 0;
+	int i;
+
+	/* If process was forked, VMA is still there but vm_private_data is set
+	 * to NULL.
+	 */
+	if (!encl)
+		return -EFAULT;
+
+	flags = atomic_read(&encl->flags);
+
+	if (!(flags & SGX_ENCL_DEBUG) || !(flags & SGX_ENCL_INITIALIZED) ||
+	    (flags & SGX_ENCL_DEAD))
+		return -EFAULT;
+
+	for (i = 0; i < len; i += cnt) {
+		entry = sgx_encl_reserve_page(encl, (addr + i) & PAGE_MASK);
+		if (IS_ERR(entry)) {
+			ret = PTR_ERR(entry);
+			break;
+		}
+
+		align = ALIGN_DOWN(addr + i, sizeof(unsigned long));
+		offset = (addr + i) & (sizeof(unsigned long) - 1);
+		cnt = sizeof(unsigned long) - offset;
+		cnt = min(cnt, len - i);
+
+		ret = sgx_edbgrd(encl, entry, align, data);
+		if (ret)
+			goto out;
+
+		if (write) {
+			memcpy(data + offset, buf + i, cnt);
+			ret = sgx_edbgwr(encl, entry, align, data);
+			if (ret)
+				goto out;
+		} else
+			memcpy(buf + i, data + offset, cnt);
+
+out:
+		mutex_unlock(&encl->lock);
+
+		if (ret)
+			break;
+	}
+
+	return ret < 0 ? ret : i;
+}
+
 const struct vm_operations_struct sgx_vm_ops = {
 	.open = sgx_vma_open,
 	.fault = sgx_vma_fault,
 	.may_mprotect = sgx_vma_mprotect,
+	.access = sgx_vma_access,
 };
 
 /**
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH v30 14/20] x86/vdso: Add support for exception fixup in vDSO functions
  2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
                   ` (12 preceding siblings ...)
  2020-05-15  0:44 ` [PATCH v30 13/20] x86/sgx: ptrace() support for the SGX driver Jarkko Sakkinen
@ 2020-05-15  0:44 ` Jarkko Sakkinen
  2020-05-15  0:44 ` [PATCH v30 15/20] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
                   ` (6 subsequent siblings)
  20 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-15  0:44 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: akpm, dave.hansen, sean.j.christopherson, nhorman, npmccallum,
	haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp, josh, luto,
	kai.huang, rientjes, cedric.xing, puiterwijk, Andy Lutomirski,
	Jethro Beekman, Jarkko Sakkinen

From: Sean Christopherson <sean.j.christopherson@intel.com>

The basic concept and implementation is very similar to the kernel's
exception fixup mechanism.  The key differences are that the kernel
handler is hardcoded and the fixup entry addresses are relative to
the overall table as opposed to individual entries.

Hardcoding the kernel handler avoids the need to figure out how to
get userspace code to point at a kernel function.  Given that the
expected usage is to propagate information to userspace, dumping all
fault information into registers is likely the desired behavior for
the vast majority of yet-to-be-created functions.  Use registers
DI, SI and DX to communicate fault information, which follows Linux's
ABI for register consumption and hopefully avoids conflict with
hardware features that might leverage the fixup capabilities, e.g.
register usage for SGX instructions was at least partially designed
with calling conventions in mind.

Making fixup addresses relative to the overall table allows the table
to be stripped from the final vDSO image (it's a kernel construct)
without complicating the offset logic, e.g. entry-relative addressing
would also need to account for the table's location relative to the
image.

Regarding stripping the table, modify vdso2c to extract the table from
the raw, a.k.a. unstripped, data and dump it as a standalone byte array
in the resulting .c file.  The original base of the table, its length
and a pointer to the byte array are captured in struct vdso_image.
Alternatively, the table could be dumped directly into the struct,
but because the number of entries can vary per image, that would
require either hardcoding a max sized table into the struct definition
or defining the table as a flexible length array.  The flexible length
array approach has zero benefits, e.g. the base/size are still needed,
and prevents reusing the extraction code, while hardcoding the max size
adds ongoing maintenance just to avoid exporting the explicit size.

The immediate use case is for Intel Software Guard Extensions (SGX).
SGX introduces a new CPL3-only "enclave" mode that runs as a sort of
black box shared object that is hosted by an untrusted "normal" CPl3
process.

Entering an enclave can only be done through SGX-specific instructions,
EENTER and ERESUME, and is a non-trivial process.  Because of the
complexity of transitioning to/from an enclave, the vast majority of
enclaves are expected to utilize a library to handle the actual
transitions.  This is roughly analogous to how e.g. libc implementations
are used by most applications.

Another crucial characteristic of SGX enclaves is that they can generate
exceptions as part of their normal (at least as "normal" as SGX can be)
operation that need to be handled *in* the enclave and/or are unique
to SGX.

And because they are essentially fancy shared objects, a process can
host any number of enclaves, each of which can execute multiple threads
simultaneously.

Putting everything together, userspace enclaves will utilize a library
that must be prepared to handle any and (almost) all exceptions any time
at least one thread may be executing in an enclave.  Leveraging signals
to handle the enclave exceptions is unpleasant, to put it mildly, e.g.
the SGX library must constantly (un)register its signal handler based
on whether or not at least one thread is executing in an enclave, and
filter and forward exceptions that aren't related to its enclaves.  This
becomes particularly nasty when using multiple levels of libraries that
register signal handlers, e.g. running an enclave via cgo inside of the
Go runtime.

Enabling exception fixup in vDSO allows the kernel to provide a vDSO
function that wraps the low-level transitions to/from the enclave, i.e.
the EENTER and ERESUME instructions.  The vDSO function can intercept
exceptions that would otherwise generate a signal and return the fault
information directly to its caller, thus avoiding the need to juggle
signal handlers.

Note that unlike the kernel's _ASM_EXTABLE_HANDLE implementation, the
'C' version of _ASM_VDSO_EXTABLE_HANDLE doesn't use a pre-compiled
assembly macro.  Duplicating four lines of code is simpler than adding
the necessary infrastructure to generate pre-compiled assembly and the
intended benefit of massaging GCC's inlining algorithm is unlikely to
realized in the vDSO any time soon, if ever.

Suggested-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Jethro Beekman <jethro@fortanix.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 arch/x86/entry/vdso/Makefile          |  6 +--
 arch/x86/entry/vdso/extable.c         | 46 +++++++++++++++++++++
 arch/x86/entry/vdso/extable.h         | 29 ++++++++++++++
 arch/x86/entry/vdso/vdso-layout.lds.S |  9 ++++-
 arch/x86/entry/vdso/vdso2c.h          | 58 +++++++++++++++++++++++----
 arch/x86/include/asm/vdso.h           |  5 +++
 6 files changed, 141 insertions(+), 12 deletions(-)
 create mode 100644 arch/x86/entry/vdso/extable.c
 create mode 100644 arch/x86/entry/vdso/extable.h

diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index 433a1259f61d..657e01d34d02 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -26,7 +26,7 @@ VDSO32-$(CONFIG_IA32_EMULATION)	:= y
 vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
 
 # files to link into kernel
-obj-y				+= vma.o
+obj-y				+= vma.o extable.o
 OBJECT_FILES_NON_STANDARD_vma.o	:= n
 
 # vDSO images to build
@@ -120,8 +120,8 @@ $(obj)/%-x32.o: $(obj)/%.o FORCE
 
 targets += vdsox32.lds $(vobjx32s-y)
 
-$(obj)/%.so: OBJCOPYFLAGS := -S
-$(obj)/%.so: $(obj)/%.so.dbg FORCE
+$(obj)/%.so: OBJCOPYFLAGS := -S --remove-section __ex_table
+$(obj)/%.so: $(obj)/%.so.dbg
 	$(call if_changed,objcopy)
 
 $(obj)/vdsox32.so.dbg: $(obj)/vdsox32.lds $(vobjx32s) FORCE
diff --git a/arch/x86/entry/vdso/extable.c b/arch/x86/entry/vdso/extable.c
new file mode 100644
index 000000000000..afcf5b65beef
--- /dev/null
+++ b/arch/x86/entry/vdso/extable.c
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/err.h>
+#include <linux/mm.h>
+#include <asm/current.h>
+#include <asm/traps.h>
+#include <asm/vdso.h>
+
+struct vdso_exception_table_entry {
+	int insn, fixup;
+};
+
+bool fixup_vdso_exception(struct pt_regs *regs, int trapnr,
+			  unsigned long error_code, unsigned long fault_addr)
+{
+	const struct vdso_image *image = current->mm->context.vdso_image;
+	const struct vdso_exception_table_entry *extable;
+	unsigned int nr_entries, i;
+	unsigned long base;
+
+	/*
+	 * Do not attempt to fixup #DB or #BP.  It's impossible to identify
+	 * whether or not a #DB/#BP originated from within an SGX enclave and
+	 * SGX enclaves are currently the only use case for vDSO fixup.
+	 */
+	if (trapnr == X86_TRAP_DB || trapnr == X86_TRAP_BP)
+		return false;
+
+	if (!current->mm->context.vdso)
+		return false;
+
+	base =  (unsigned long)current->mm->context.vdso + image->extable_base;
+	nr_entries = image->extable_len / (sizeof(*extable));
+	extable = image->extable;
+
+	for (i = 0; i < nr_entries; i++) {
+		if (regs->ip == base + extable[i].insn) {
+			regs->ip = base + extable[i].fixup;
+			regs->di = trapnr;
+			regs->si = error_code;
+			regs->dx = fault_addr;
+			return true;
+		}
+	}
+
+	return false;
+}
diff --git a/arch/x86/entry/vdso/extable.h b/arch/x86/entry/vdso/extable.h
new file mode 100644
index 000000000000..aafdac396948
--- /dev/null
+++ b/arch/x86/entry/vdso/extable.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_EXTABLE_H
+#define __VDSO_EXTABLE_H
+
+/*
+ * Inject exception fixup for vDSO code.  Unlike normal exception fixup,
+ * vDSO uses a dedicated handler the addresses are relative to the overall
+ * exception table, not each individual entry.
+ */
+#ifdef __ASSEMBLY__
+#define _ASM_VDSO_EXTABLE_HANDLE(from, to)	\
+	ASM_VDSO_EXTABLE_HANDLE from to
+
+.macro ASM_VDSO_EXTABLE_HANDLE from:req to:req
+	.pushsection __ex_table, "a"
+	.long (\from) - __ex_table
+	.long (\to) - __ex_table
+	.popsection
+.endm
+#else
+#define _ASM_VDSO_EXTABLE_HANDLE(from, to)	\
+	".pushsection __ex_table, \"a\"\n"      \
+	".long (" #from ") - __ex_table\n"      \
+	".long (" #to ") - __ex_table\n"        \
+	".popsection\n"
+#endif
+
+#endif /* __VDSO_EXTABLE_H */
+
diff --git a/arch/x86/entry/vdso/vdso-layout.lds.S b/arch/x86/entry/vdso/vdso-layout.lds.S
index 4d152933547d..dc8da7695859 100644
--- a/arch/x86/entry/vdso/vdso-layout.lds.S
+++ b/arch/x86/entry/vdso/vdso-layout.lds.S
@@ -75,11 +75,18 @@ SECTIONS
 	 * stuff that isn't used at runtime in between.
 	 */
 
-	.text		: { *(.text*) }			:text	=0x90909090,
+	.text		: {
+		*(.text*)
+		*(.fixup)
+	}						:text	=0x90909090,
+
+
 
 	.altinstructions	: { *(.altinstructions) }	:text
 	.altinstr_replacement	: { *(.altinstr_replacement) }	:text
 
+	__ex_table		: { *(__ex_table) }		:text
+
 	/DISCARD/ : {
 		*(.discard)
 		*(.discard.*)
diff --git a/arch/x86/entry/vdso/vdso2c.h b/arch/x86/entry/vdso/vdso2c.h
index a20b134de2a8..04d04e46c98c 100644
--- a/arch/x86/entry/vdso/vdso2c.h
+++ b/arch/x86/entry/vdso/vdso2c.h
@@ -5,6 +5,41 @@
  * are built for 32-bit userspace.
  */
 
+static void BITSFUNC(copy)(FILE *outfile, const unsigned char *data, size_t len)
+{
+	size_t i;
+
+	for (i = 0; i < len; i++) {
+		if (i % 10 == 0)
+			fprintf(outfile, "\n\t");
+		fprintf(outfile, "0x%02X, ", (int)(data)[i]);
+	}
+}
+
+
+/*
+ * Extract a section from the input data into a standalone blob.  Used to
+ * capture kernel-only data that needs to persist indefinitely, e.g. the
+ * exception fixup tables, but only in the kernel, i.e. the section can
+ * be stripped from the final vDSO image.
+ */
+static void BITSFUNC(extract)(const unsigned char *data, size_t data_len,
+			      FILE *outfile, ELF(Shdr) *sec, const char *name)
+{
+	unsigned long offset;
+	size_t len;
+
+	offset = (unsigned long)GET_LE(&sec->sh_offset);
+	len = (size_t)GET_LE(&sec->sh_size);
+
+	if (offset + len > data_len)
+		fail("section to extract overruns input data");
+
+	fprintf(outfile, "static const unsigned char %s[%lu] = {", name, len);
+	BITSFUNC(copy)(outfile, data + offset, len);
+	fprintf(outfile, "\n};\n\n");
+}
+
 static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
 			 void *stripped_addr, size_t stripped_len,
 			 FILE *outfile, const char *image_name)
@@ -14,9 +49,8 @@ static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
 	unsigned long mapping_size;
 	ELF(Ehdr) *hdr = (ELF(Ehdr) *)raw_addr;
 	int i;
-	unsigned long j;
 	ELF(Shdr) *symtab_hdr = NULL, *strtab_hdr, *secstrings_hdr,
-		*alt_sec = NULL;
+		*alt_sec = NULL, *extable_sec = NULL;
 	ELF(Dyn) *dyn = 0, *dyn_end = 0;
 	const char *secstrings;
 	INT_BITS syms[NSYMS] = {};
@@ -78,6 +112,8 @@ static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
 		if (!strcmp(secstrings + GET_LE(&sh->sh_name),
 			    ".altinstructions"))
 			alt_sec = sh;
+		if (!strcmp(secstrings + GET_LE(&sh->sh_name), "__ex_table"))
+			extable_sec = sh;
 	}
 
 	if (!symtab_hdr)
@@ -150,13 +186,11 @@ static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
 	fprintf(outfile,
 		"static unsigned char raw_data[%lu] __ro_after_init __aligned(PAGE_SIZE) = {",
 		mapping_size);
-	for (j = 0; j < stripped_len; j++) {
-		if (j % 10 == 0)
-			fprintf(outfile, "\n\t");
-		fprintf(outfile, "0x%02X, ",
-			(int)((unsigned char *)stripped_addr)[j]);
-	}
+	BITSFUNC(copy)(outfile, stripped_addr, stripped_len);
 	fprintf(outfile, "\n};\n\n");
+	if (extable_sec)
+		BITSFUNC(extract)(raw_addr, raw_len, outfile,
+				  extable_sec, "extable");
 
 	fprintf(outfile, "const struct vdso_image %s = {\n", image_name);
 	fprintf(outfile, "\t.data = raw_data,\n");
@@ -167,6 +201,14 @@ static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
 		fprintf(outfile, "\t.alt_len = %lu,\n",
 			(unsigned long)GET_LE(&alt_sec->sh_size));
 	}
+	if (extable_sec) {
+		fprintf(outfile, "\t.extable_base = %lu,\n",
+			(unsigned long)GET_LE(&extable_sec->sh_offset));
+		fprintf(outfile, "\t.extable_len = %lu,\n",
+			(unsigned long)GET_LE(&extable_sec->sh_size));
+		fprintf(outfile, "\t.extable = extable,\n");
+	}
+
 	for (i = 0; i < NSYMS; i++) {
 		if (required_syms[i].export && syms[i])
 			fprintf(outfile, "\t.sym_%s = %" PRIi64 ",\n",
diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h
index bbcdc7b8f963..b5d23470f56b 100644
--- a/arch/x86/include/asm/vdso.h
+++ b/arch/x86/include/asm/vdso.h
@@ -15,6 +15,8 @@ struct vdso_image {
 	unsigned long size;   /* Always a multiple of PAGE_SIZE */
 
 	unsigned long alt, alt_len;
+	unsigned long extable_base, extable_len;
+	const void *extable;
 
 	long sym_vvar_start;  /* Negative offset to the vvar area */
 
@@ -45,6 +47,9 @@ extern void __init init_vdso_image(const struct vdso_image *image);
 
 extern int map_vdso_once(const struct vdso_image *image, unsigned long addr);
 
+extern bool fixup_vdso_exception(struct pt_regs *regs, int trapnr,
+				 unsigned long error_code,
+				 unsigned long fault_addr);
 #endif /* __ASSEMBLER__ */
 
 #endif /* _ASM_X86_VDSO_H */
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH v30 15/20] x86/fault: Add helper function to sanitize error code
  2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
                   ` (13 preceding siblings ...)
  2020-05-15  0:44 ` [PATCH v30 14/20] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
@ 2020-05-15  0:44 ` Jarkko Sakkinen
  2020-05-15  0:44 ` [PATCH v30 16/20] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
                   ` (5 subsequent siblings)
  20 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-15  0:44 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: akpm, dave.hansen, sean.j.christopherson, nhorman, npmccallum,
	haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp, josh, luto,
	kai.huang, rientjes, cedric.xing, puiterwijk, Jethro Beekman,
	Jarkko Sakkinen

From: Sean Christopherson <sean.j.christopherson@intel.com>

Add helper function to sanitize error code to prepare for vDSO exception
fixup, which will expose the error code to userspace and runs before
set_signal_archinfo(), i.e. suppresses the signal when fixup is successful.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Jethro Beekman <jethro@fortanix.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 arch/x86/mm/fault.c | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 16c53c874bb9..23666e34abbc 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -704,6 +704,18 @@ pgtable_bad(struct pt_regs *regs, unsigned long error_code,
 	oops_end(flags, regs, sig);
 }
 
+static void sanitize_error_code(unsigned long address,
+				unsigned long *error_code)
+{
+	/*
+	 * To avoid leaking information about the kernel page
+	 * table layout, pretend that user-mode accesses to
+	 * kernel addresses are always protection faults.
+	 */
+	if (address >= TASK_SIZE_MAX)
+		*error_code |= X86_PF_PROT;
+}
+
 static void set_signal_archinfo(unsigned long address,
 				unsigned long error_code)
 {
@@ -760,6 +772,8 @@ no_context(struct pt_regs *regs, unsigned long error_code,
 		 * faulting through the emulate_vsyscall() logic.
 		 */
 		if (current->thread.sig_on_uaccess_err && signal) {
+			sanitize_error_code(address, &error_code);
+
 			set_signal_archinfo(address, error_code);
 
 			/* XXX: hwpoison faults will set the wrong code. */
@@ -908,13 +922,7 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
 		if (is_errata100(regs, address))
 			return;
 
-		/*
-		 * To avoid leaking information about the kernel page table
-		 * layout, pretend that user-mode accesses to kernel addresses
-		 * are always protection faults.
-		 */
-		if (address >= TASK_SIZE_MAX)
-			error_code |= X86_PF_PROT;
+		sanitize_error_code(address, &error_code);
 
 		if (likely(show_unhandled_signals))
 			show_signal_msg(regs, error_code, address, tsk);
@@ -1031,6 +1039,8 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
 	if (is_prefetch(regs, error_code, address))
 		return;
 
+	sanitize_error_code(address, &error_code);
+
 	set_signal_archinfo(address, error_code);
 
 #ifdef CONFIG_MEMORY_FAILURE
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH v30 16/20] x86/traps: Attempt to fixup exceptions in vDSO before signaling
  2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
                   ` (14 preceding siblings ...)
  2020-05-15  0:44 ` [PATCH v30 15/20] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
@ 2020-05-15  0:44 ` Jarkko Sakkinen
  2020-05-15  0:44 ` [PATCH v30 17/20] x86/vdso: Implement a vDSO for Intel SGX enclave call Jarkko Sakkinen
                   ` (4 subsequent siblings)
  20 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-15  0:44 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: akpm, dave.hansen, sean.j.christopherson, nhorman, npmccallum,
	haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp, josh, luto,
	kai.huang, rientjes, cedric.xing, puiterwijk, Andy Lutomirski,
	Jethro Beekman, Jarkko Sakkinen

From: Sean Christopherson <sean.j.christopherson@intel.com>

vDSO functions can now leverage an exception fixup mechanism similar to
kernel exception fixup.  For vDSO exception fixup, the initial user is
Intel's Software Guard Extensions (SGX), which will wrap the low-level
transitions to/from the enclave, i.e. EENTER and ERESUME instructions,
in a vDSO function and leverage fixup to intercept exceptions that would
otherwise generate a signal.  This allows the vDSO wrapper to return the
fault information directly to its caller, obviating the need for SGX
applications and libraries to juggle signal handlers.

Attempt to fixup vDSO exceptions immediately prior to populating and
sending signal information.  Except for the delivery mechanism, an
exception in a vDSO function should be treated like any other exception
in userspace, e.g. any fault that is successfully handled by the kernel
should not be directly visible to userspace.

Although it's debatable whether or not all exceptions are of interest to
enclaves, defer to the vDSO fixup to decide whether to do fixup or
generate a signal.  Future users of vDSO fixup, if there ever are any,
will undoubtedly have different requirements than SGX enclaves, e.g. the
fixup vs. signal logic can be made function specific if/when necessary.

Suggested-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Jethro Beekman <jethro@fortanix.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 arch/x86/kernel/traps.c | 14 ++++++++++++++
 arch/x86/mm/fault.c     |  8 ++++++++
 2 files changed, 22 insertions(+)

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index d54cffdc7cac..cce8fb2c560d 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -57,6 +57,7 @@
 #include <asm/umip.h>
 #include <asm/insn.h>
 #include <asm/insn-eval.h>
+#include <asm/vdso.h>
 
 #ifdef CONFIG_X86_64
 #include <asm/x86_init.h>
@@ -206,6 +207,9 @@ do_trap_no_signal(struct task_struct *tsk, int trapnr, const char *str,
 		tsk->thread.error_code = error_code;
 		tsk->thread.trap_nr = trapnr;
 		die(str, regs, error_code);
+	} else {
+		if (fixup_vdso_exception(regs, trapnr, error_code, 0))
+			return 0;
 	}
 
 	/*
@@ -538,6 +542,9 @@ dotraplinkage void do_general_protection(struct pt_regs *regs, long error_code)
 		tsk->thread.error_code = error_code;
 		tsk->thread.trap_nr = X86_TRAP_GP;
 
+		if (fixup_vdso_exception(regs, X86_TRAP_GP, error_code, 0))
+			return;
+
 		show_signal(tsk, SIGSEGV, "", desc, regs, error_code);
 		force_sig(SIGSEGV);
 
@@ -791,6 +798,10 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
 							SIGTRAP) == NOTIFY_STOP)
 		goto exit;
 
+	if (user_mode(regs) &&
+	    fixup_vdso_exception(regs, X86_TRAP_DB, error_code, 0))
+		goto exit;
+
 	/*
 	 * Let others (NMI) know that the debug stack is in use
 	 * as we may switch to the interrupt stack.
@@ -871,6 +882,9 @@ static void math_error(struct pt_regs *regs, int error_code, int trapnr)
 	if (!si_code)
 		return;
 
+	if (fixup_vdso_exception(regs, trapnr, error_code, 0))
+		return;
+
 	force_sig_fault(SIGFPE, si_code,
 			(void __user *)uprobe_get_trap_addr(regs));
 }
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 23666e34abbc..e9ed3c7299ac 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -30,6 +30,7 @@
 #include <asm/desc.h>			/* store_idt(), ...		*/
 #include <asm/cpu_entry_area.h>		/* exception stack		*/
 #include <asm/pgtable_areas.h>		/* VMALLOC_START, ...		*/
+#include <asm/vdso.h>			/* fixup_vdso_exception()	*/
 
 #define CREATE_TRACE_POINTS
 #include <asm/trace/exceptions.h>
@@ -924,6 +925,10 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
 
 		sanitize_error_code(address, &error_code);
 
+		if (fixup_vdso_exception(regs, X86_TRAP_PF, error_code,
+		    address))
+			return;
+
 		if (likely(show_unhandled_signals))
 			show_signal_msg(regs, error_code, address, tsk);
 
@@ -1041,6 +1046,9 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
 
 	sanitize_error_code(address, &error_code);
 
+	if (fixup_vdso_exception(regs, X86_TRAP_PF, error_code, address))
+		return;
+
 	set_signal_archinfo(address, error_code);
 
 #ifdef CONFIG_MEMORY_FAILURE
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH v30 17/20] x86/vdso: Implement a vDSO for Intel SGX enclave call
  2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
                   ` (15 preceding siblings ...)
  2020-05-15  0:44 ` [PATCH v30 16/20] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
@ 2020-05-15  0:44 ` Jarkko Sakkinen
  2020-05-15  0:44 ` [PATCH v30 18/20] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
                   ` (3 subsequent siblings)
  20 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-15  0:44 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: akpm, dave.hansen, sean.j.christopherson, nhorman, npmccallum,
	haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp, josh, luto,
	kai.huang, rientjes, cedric.xing, puiterwijk, Andy Lutomirski,
	Jethro Beekman, Jarkko Sakkinen

From: Sean Christopherson <sean.j.christopherson@intel.com>

An SGX runtime must be aware of the exceptions, which happen inside an
enclave. Introduce a vDSO call that wraps EENTER/ERESUME cycle and returns
the CPU exception back to the caller exactly when it happens.

Kernel fixups the exception information to RDI, RSI and RDX. The SGX call
vDSO handler fills this information to the user provided buffer or
alternatively trigger user provided callback at the time of the exception.

The calling convention is custom and does not follow System V x86-64 ABI.

Suggested-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Co-developed-by: Cedric Xing <cedric.xing@intel.com>
Signed-off-by: Cedric Xing <cedric.xing@intel.com>
Acked-by: Jethro Beekman <jethro@fortanix.com>
Tested-by: Jethro Beekman <jethro@fortanix.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 arch/x86/entry/vdso/Makefile             |   2 +
 arch/x86/entry/vdso/vdso.lds.S           |   1 +
 arch/x86/entry/vdso/vsgx_enter_enclave.S | 131 +++++++++++++++++++++++
 arch/x86/include/asm/enclu.h             |   8 ++
 arch/x86/include/uapi/asm/sgx.h          |  98 +++++++++++++++++
 5 files changed, 240 insertions(+)
 create mode 100644 arch/x86/entry/vdso/vsgx_enter_enclave.S
 create mode 100644 arch/x86/include/asm/enclu.h

diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index 657e01d34d02..fa50c76a17a8 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -24,6 +24,7 @@ VDSO32-$(CONFIG_IA32_EMULATION)	:= y
 
 # files to link into the vdso
 vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
+vobjs-$(VDSO64-y)		+= vsgx_enter_enclave.o
 
 # files to link into kernel
 obj-y				+= vma.o extable.o
@@ -90,6 +91,7 @@ $(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS
 CFLAGS_REMOVE_vclock_gettime.o = -pg
 CFLAGS_REMOVE_vdso32/vclock_gettime.o = -pg
 CFLAGS_REMOVE_vgetcpu.o = -pg
+CFLAGS_REMOVE_vsgx_enter_enclave.o = -pg
 
 #
 # X32 processes use x32 vDSO to access 64bit kernel data.
diff --git a/arch/x86/entry/vdso/vdso.lds.S b/arch/x86/entry/vdso/vdso.lds.S
index 36b644e16272..4bf48462fca7 100644
--- a/arch/x86/entry/vdso/vdso.lds.S
+++ b/arch/x86/entry/vdso/vdso.lds.S
@@ -27,6 +27,7 @@ VERSION {
 		__vdso_time;
 		clock_getres;
 		__vdso_clock_getres;
+		__vdso_sgx_enter_enclave;
 	local: *;
 	};
 }
diff --git a/arch/x86/entry/vdso/vsgx_enter_enclave.S b/arch/x86/entry/vdso/vsgx_enter_enclave.S
new file mode 100644
index 000000000000..be7e467e1efb
--- /dev/null
+++ b/arch/x86/entry/vdso/vsgx_enter_enclave.S
@@ -0,0 +1,131 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/linkage.h>
+#include <asm/export.h>
+#include <asm/errno.h>
+#include <asm/enclu.h>
+
+#include "extable.h"
+
+#define EX_LEAF		0*8
+#define EX_TRAPNR	0*8+4
+#define EX_ERROR_CODE	0*8+6
+#define EX_ADDRESS	1*8
+
+.code64
+.section .text, "ax"
+
+SYM_FUNC_START(__vdso_sgx_enter_enclave)
+	/* Prolog */
+	.cfi_startproc
+	push	%rbp
+	.cfi_adjust_cfa_offset	8
+	.cfi_rel_offset		%rbp, 0
+	mov	%rsp, %rbp
+	.cfi_def_cfa_register	%rbp
+	push	%rbx
+	.cfi_rel_offset		%rbx, -8
+
+	mov	%ecx, %eax
+.Lenter_enclave:
+	/* EENTER <= leaf <= ERESUME */
+	cmp	$EENTER, %eax
+	jb	.Linvalid_leaf
+	cmp	$ERESUME, %eax
+	ja	.Linvalid_leaf
+
+	/* Load TCS and AEP */
+	mov	0x10(%rbp), %rbx
+	lea	.Lasync_exit_pointer(%rip), %rcx
+
+	/* Single ENCLU serving as both EENTER and AEP (ERESUME) */
+.Lasync_exit_pointer:
+.Lenclu_eenter_eresume:
+	enclu
+
+	/* EEXIT jumps here unless the enclave is doing something fancy. */
+	xor	%eax, %eax
+
+	/* Invoke userspace's exit handler if one was provided. */
+.Lhandle_exit:
+	cmp	$0, 0x20(%rbp)
+	jne	.Linvoke_userspace_handler
+
+.Lout:
+	pop	%rbx
+	leave
+	.cfi_def_cfa		%rsp, 8
+	ret
+
+	/* The out-of-line code runs with the pre-leave stack frame. */
+	.cfi_def_cfa		%rbp, 16
+
+.Linvalid_leaf:
+	mov	$(-EINVAL), %eax
+	jmp	.Lout
+
+.Lhandle_exception:
+	mov	0x18(%rbp), %rcx
+	test    %rcx, %rcx
+	je	.Lskip_exception_info
+
+	/* Fill optional exception info. */
+	mov	%eax, EX_LEAF(%rcx)
+	mov	%di,  EX_TRAPNR(%rcx)
+	mov	%si,  EX_ERROR_CODE(%rcx)
+	mov	%rdx, EX_ADDRESS(%rcx)
+.Lskip_exception_info:
+	mov	$(-EFAULT), %eax
+	jmp	.Lhandle_exit
+
+.Linvoke_userspace_handler:
+	/* Pass the untrusted RSP (at exit) to the callback via %rcx. */
+	mov	%rsp, %rcx
+
+	/* Save the untrusted RSP offset in %rbx (non-volatile register). */
+	mov	%rsp, %rbx
+	and	$0xf, %rbx
+
+	/*
+	 * Align stack per x86_64 ABI. Note, %rsp needs to be 16-byte aligned
+	 * _after_ pushing the parameters on the stack, hence the bonus push.
+	 */
+	and	$-0x10, %rsp
+	push	%rax
+
+	/* Push @e, the "return" value and @tcs as params to the callback. */
+	push	0x18(%rbp)
+	push	%rax
+	push	0x10(%rbp)
+
+	/* Clear RFLAGS.DF per x86_64 ABI */
+	cld
+
+	/* Load the callback pointer to %rax and invoke it via retpoline. */
+	mov	0x20(%rbp), %rax
+	call	.Lretpoline
+
+	/* Undo the post-exit %rsp adjustment. */
+	lea	0x20(%rsp, %rbx), %rsp
+
+	/*
+	 * If the return from callback is zero or negative, return immediately,
+	 * else re-execute ENCLU with the postive return value interpreted as
+	 * the requested ENCLU leaf.
+	 */
+	cmp	$0, %eax
+	jle	.Lout
+	jmp	.Lenter_enclave
+
+.Lretpoline:
+	call	2f
+1:	pause
+	lfence
+	jmp	1b
+2:	mov	%rax, (%rsp)
+	ret
+	.cfi_endproc
+
+_ASM_VDSO_EXTABLE_HANDLE(.Lenclu_eenter_eresume, .Lhandle_exception)
+
+SYM_FUNC_END(__vdso_sgx_enter_enclave)
diff --git a/arch/x86/include/asm/enclu.h b/arch/x86/include/asm/enclu.h
new file mode 100644
index 000000000000..06157b3e9ede
--- /dev/null
+++ b/arch/x86/include/asm/enclu.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_ENCLU_H
+#define _ASM_X86_ENCLU_H
+
+#define EENTER	0x02
+#define ERESUME	0x03
+
+#endif /* _ASM_X86_ENCLU_H */
diff --git a/arch/x86/include/uapi/asm/sgx.h b/arch/x86/include/uapi/asm/sgx.h
index 57d0d30c79b3..3760e5d5dc0c 100644
--- a/arch/x86/include/uapi/asm/sgx.h
+++ b/arch/x86/include/uapi/asm/sgx.h
@@ -74,4 +74,102 @@ struct sgx_enclave_set_attribute {
 	__u64 attribute_fd;
 };
 
+/**
+ * struct sgx_enclave_exception - structure to report exceptions encountered in
+ *				  __vdso_sgx_enter_enclave()
+ *
+ * @leaf:	ENCLU leaf from \%eax at time of exception
+ * @trapnr:	exception trap number, a.k.a. fault vector
+ * @error_code:	exception error code
+ * @address:	exception address, e.g. CR2 on a #PF
+ * @reserved:	reserved for future use
+ */
+struct sgx_enclave_exception {
+	__u32 leaf;
+	__u16 trapnr;
+	__u16 error_code;
+	__u64 address;
+	__u64 reserved[2];
+};
+
+/**
+ * typedef sgx_enclave_exit_handler_t - Exit handler function accepted by
+ *					__vdso_sgx_enter_enclave()
+ *
+ * @rdi:	RDI at the time of enclave exit
+ * @rsi:	RSI at the time of enclave exit
+ * @rdx:	RDX at the time of enclave exit
+ * @ursp:	RSP at the time of enclave exit (untrusted stack)
+ * @r8:		R8 at the time of enclave exit
+ * @r9:		R9 at the time of enclave exit
+ * @tcs:	Thread Control Structure used to enter enclave
+ * @ret:	0 on success (EEXIT), -EFAULT on an exception
+ * @e:		Pointer to struct sgx_enclave_exception (as provided by caller)
+ */
+typedef int (*sgx_enclave_exit_handler_t)(long rdi, long rsi, long rdx,
+					  long ursp, long r8, long r9,
+					  void *tcs, int ret,
+					  struct sgx_enclave_exception *e);
+
+/**
+ * __vdso_sgx_enter_enclave() - Enter an SGX enclave
+ * @rdi:	Pass-through value for RDI
+ * @rsi:	Pass-through value for RSI
+ * @rdx:	Pass-through value for RDX
+ * @leaf:	ENCLU leaf, must be EENTER or ERESUME
+ * @r8:		Pass-through value for R8
+ * @r9:		Pass-through value for R9
+ * @tcs:	TCS, must be non-NULL
+ * @e:		Optional struct sgx_enclave_exception instance
+ * @handler:	Optional enclave exit handler
+ *
+ * NOTE: __vdso_sgx_enter_enclave() does not ensure full compliance with the
+ * x86-64 ABI, e.g. doesn't explicitly clear EFLAGS.DF after EEXIT.  Except for
+ * non-volatile general purpose registers, preserving/setting state in
+ * accordance with the x86-64 ABI is the responsibility of the enclave and its
+ * runtime, i.e. __vdso_sgx_enter_enclave() cannot be called from C code
+ * without careful consideration by both the enclave and its runtime.
+ *
+ * All general purpose registers except RAX, RBX and RCX are passed as-is to
+ * the enclave.  RAX, RBX and RCX are consumed by EENTER and ERESUME and are
+ * loaded with @leaf, asynchronous exit pointer, and @tcs respectively.
+ *
+ * RBP and the stack are used to anchor __vdso_sgx_enter_enclave() to the
+ * pre-enclave state, e.g. to retrieve @e and @handler after an enclave exit.
+ * All other registers are available for use by the enclave and its runtime,
+ * e.g. an enclave can push additional data onto the stack (and modify RSP) to
+ * pass information to the optional exit handler (see below).
+ *
+ * Most exceptions reported on ENCLU, including those that occur within the
+ * enclave, are fixed up and reported synchronously instead of being delivered
+ * via a standard signal. Debug Exceptions (#DB) and Breakpoints (#BP) are
+ * never fixed up and are always delivered via standard signals. On synchrously
+ * reported exceptions, -EFAULT is returned and details about the exception are
+ * recorded in @e, the optional sgx_enclave_exception struct.
+
+ * If an exit handler is provided, the handler will be invoked on synchronous
+ * exits from the enclave and for all synchronously reported exceptions. In
+ * latter case, @e is filled prior to invoking the handler.
+ *
+ * The exit handler's return value is interpreted as follows:
+ *  >0:		continue, restart __vdso_sgx_enter_enclave() with @ret as @leaf
+ *   0:		success, return @ret to the caller
+ *  <0:		error, return @ret to the caller
+ *
+ * The exit handler may transfer control, e.g. via longjmp() or C++ exception,
+ * without returning to __vdso_sgx_enter_enclave().
+ *
+ * Return:
+ *  0 on success,
+ *  -EINVAL if ENCLU leaf is not allowed,
+ *  -EFAULT if an exception occurs on ENCLU or within the enclave
+ *  -errno for all other negative values returned by the userspace exit handler
+ */
+typedef int (*vdso_sgx_enter_enclave_t)(unsigned long rdi, unsigned long rsi,
+					unsigned long rdx, unsigned int leaf,
+					unsigned long r8,  unsigned long r9,
+					void *tcs,
+					struct sgx_enclave_exception *e,
+					sgx_enclave_exit_handler_t handler);
+
 #endif /* _UAPI_ASM_X86_SGX_H */
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH v30 18/20] selftests/x86: Add a selftest for SGX
  2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
                   ` (16 preceding siblings ...)
  2020-05-15  0:44 ` [PATCH v30 17/20] x86/vdso: Implement a vDSO for Intel SGX enclave call Jarkko Sakkinen
@ 2020-05-15  0:44 ` Jarkko Sakkinen
  2020-05-15  0:44 ` [PATCH v30 19/20] docs: x86/sgx: Document SGX micro architecture and kernel internals Jarkko Sakkinen
                   ` (2 subsequent siblings)
  20 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-15  0:44 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: akpm, dave.hansen, sean.j.christopherson, nhorman, npmccallum,
	haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp, josh, luto,
	kai.huang, rientjes, cedric.xing, puiterwijk, Jarkko Sakkinen,
	linux-kselftest

Add a selftest for SGX. It is a trivial test where a simple enclave
copies one 64-bit word of memory between two memory locations.

Cc: linux-kselftest@vger.kernel.org
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 tools/testing/selftests/Makefile              |   1 +
 tools/testing/selftests/sgx/.gitignore        |   2 +
 tools/testing/selftests/sgx/Makefile          |  53 +++
 tools/testing/selftests/sgx/call.S            |  54 +++
 tools/testing/selftests/sgx/defines.h         |  21 +
 tools/testing/selftests/sgx/load.c            | 282 +++++++++++++
 tools/testing/selftests/sgx/main.c            | 199 +++++++++
 tools/testing/selftests/sgx/main.h            |  38 ++
 tools/testing/selftests/sgx/sigstruct.c       | 395 ++++++++++++++++++
 tools/testing/selftests/sgx/test_encl.c       |  20 +
 tools/testing/selftests/sgx/test_encl.lds     |  40 ++
 .../selftests/sgx/test_encl_bootstrap.S       |  89 ++++
 12 files changed, 1194 insertions(+)
 create mode 100644 tools/testing/selftests/sgx/.gitignore
 create mode 100644 tools/testing/selftests/sgx/Makefile
 create mode 100644 tools/testing/selftests/sgx/call.S
 create mode 100644 tools/testing/selftests/sgx/defines.h
 create mode 100644 tools/testing/selftests/sgx/load.c
 create mode 100644 tools/testing/selftests/sgx/main.c
 create mode 100644 tools/testing/selftests/sgx/main.h
 create mode 100644 tools/testing/selftests/sgx/sigstruct.c
 create mode 100644 tools/testing/selftests/sgx/test_encl.c
 create mode 100644 tools/testing/selftests/sgx/test_encl.lds
 create mode 100644 tools/testing/selftests/sgx/test_encl_bootstrap.S

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 2ff68702fd41..008497495ae4 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -64,6 +64,7 @@ TARGETS += user
 TARGETS += vm
 TARGETS += x86
 TARGETS += zram
+TARGETS += sgx
 #Please keep the TARGETS list alphabetically sorted
 # Run "make quicktest=1 run_tests" or
 # "make quicktest=1 kselftest" from top level Makefile
diff --git a/tools/testing/selftests/sgx/.gitignore b/tools/testing/selftests/sgx/.gitignore
new file mode 100644
index 000000000000..fbaf0bda9a92
--- /dev/null
+++ b/tools/testing/selftests/sgx/.gitignore
@@ -0,0 +1,2 @@
+test_sgx
+test_encl.elf
diff --git a/tools/testing/selftests/sgx/Makefile b/tools/testing/selftests/sgx/Makefile
new file mode 100644
index 000000000000..95e5c4df8014
--- /dev/null
+++ b/tools/testing/selftests/sgx/Makefile
@@ -0,0 +1,53 @@
+top_srcdir = ../../../..
+
+include ../lib.mk
+
+.PHONY: all clean
+
+CAN_BUILD_X86_64 := $(shell ../x86/check_cc.sh $(CC) \
+			    ../x86/trivial_64bit_program.c)
+
+ifndef OBJCOPY
+OBJCOPY := $(CROSS_COMPILE)objcopy
+endif
+
+INCLUDES := -I$(top_srcdir)/tools/include
+HOST_CFLAGS := -Wall -Werror -g $(INCLUDES) -fPIC -z noexecstack
+ENCL_CFLAGS := -Wall -Werror -static -nostdlib -nostartfiles -fPIC \
+	       -fno-stack-protector -mrdrnd $(INCLUDES)
+
+TEST_CUSTOM_PROGS := $(OUTPUT)/test_sgx $(OUTPUT)/test_encl.elf
+
+ifeq ($(CAN_BUILD_X86_64), 1)
+all: $(TEST_CUSTOM_PROGS)
+endif
+
+$(OUTPUT)/test_sgx: $(OUTPUT)/main.o \
+		    $(OUTPUT)/load.o \
+		    $(OUTPUT)/sigstruct.o \
+		    $(OUTPUT)/call.o
+	$(CC) $(HOST_CFLAGS) -o $@ $^ -lcrypto
+
+$(OUTPUT)/main.o: main.c
+	$(CC) $(HOST_CFLAGS) -c $< -o $@
+
+$(OUTPUT)/load.o: load.c
+	$(CC) $(HOST_CFLAGS) -c $< -o $@
+
+$(OUTPUT)/sigstruct.o: sigstruct.c
+	$(CC) $(HOST_CFLAGS) -c $< -o $@
+
+$(OUTPUT)/call.o: call.S
+	$(CC) $(HOST_CFLAGS) -c $< -o $@
+
+$(OUTPUT)/test_encl.elf: test_encl.lds test_encl.c test_encl_bootstrap.S
+	$(CC) $(ENCL_CFLAGS) -T $^ -o $@
+
+EXTRA_CLEAN := \
+	$(OUTPUT)/test_encl.elf \
+	$(OUTPUT)/load.o \
+	$(OUTPUT)/call.o \
+	$(OUTPUT)/main.o \
+	$(OUTPUT)/sigstruct.o \
+	$(OUTPUT)/test_sgx \
+	$(OUTPUT)/test_sgx.o \
diff --git a/tools/testing/selftests/sgx/call.S b/tools/testing/selftests/sgx/call.S
new file mode 100644
index 000000000000..77131e83db42
--- /dev/null
+++ b/tools/testing/selftests/sgx/call.S
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
+/**
+* Copyright(c) 2016-18 Intel Corporation.
+*/
+
+	.text
+
+	.macro ENCLU
+	.byte 0x0f, 0x01, 0xd7
+	.endm
+
+	.text
+
+	.global sgx_call_vdso
+sgx_call_vdso:
+	.cfi_startproc
+	push	%r15
+	.cfi_adjust_cfa_offset	8
+	.cfi_rel_offset		%r15, 0
+	push	%r14
+	.cfi_adjust_cfa_offset	8
+	.cfi_rel_offset		%r14, 0
+	push	%r13
+	.cfi_adjust_cfa_offset	8
+	.cfi_rel_offset		%r13, 0
+	push	%r12
+	.cfi_adjust_cfa_offset	8
+	.cfi_rel_offset		%r12, 0
+	push	%rbx
+	.cfi_adjust_cfa_offset	8
+	.cfi_rel_offset		%rbx, 0
+	push	$0
+	.cfi_adjust_cfa_offset	8
+	push	0x48(%rsp)
+	.cfi_adjust_cfa_offset	8
+	push	0x48(%rsp)
+	.cfi_adjust_cfa_offset	8
+	push	0x48(%rsp)
+	.cfi_adjust_cfa_offset	8
+	call	*eenter(%rip)
+	add	$0x20, %rsp
+	.cfi_adjust_cfa_offset	-0x20
+	pop	%rbx
+	.cfi_adjust_cfa_offset	-8
+	pop	%r12
+	.cfi_adjust_cfa_offset	-8
+	pop	%r13
+	.cfi_adjust_cfa_offset	-8
+	pop	%r14
+	.cfi_adjust_cfa_offset	-8
+	pop	%r15
+	.cfi_adjust_cfa_offset	-8
+	ret
+	.cfi_endproc
diff --git a/tools/testing/selftests/sgx/defines.h b/tools/testing/selftests/sgx/defines.h
new file mode 100644
index 000000000000..be8969922804
--- /dev/null
+++ b/tools/testing/selftests/sgx/defines.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright(c) 2016-19 Intel Corporation.
+ */
+
+#ifndef DEFINES_H
+#define DEFINES_H
+
+#include <stdint.h>
+
+#define PAGE_SIZE 4096
+#define PAGE_MASK (~(PAGE_SIZE - 1))
+
+#define __aligned(x) __attribute__((__aligned__(x)))
+#define __packed __attribute__((packed))
+
+#include "../../../../arch/x86/kernel/cpu/sgx/arch.h"
+#include "../../../../arch/x86/include/asm/enclu.h"
+#include "../../../../arch/x86/include/uapi/asm/sgx.h"
+
+#endif /* DEFINES_H */
diff --git a/tools/testing/selftests/sgx/load.c b/tools/testing/selftests/sgx/load.c
new file mode 100644
index 000000000000..53c565347e9e
--- /dev/null
+++ b/tools/testing/selftests/sgx/load.c
@@ -0,0 +1,282 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-18 Intel Corporation.
+
+#include <assert.h>
+#include <elf.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include "defines.h"
+#include "main.h"
+
+void encl_delete(struct encl *encl)
+{
+	if (encl->encl_base)
+		munmap((void *)encl->encl_base, encl->encl_size);
+
+	if (encl->bin)
+		munmap(encl->bin, encl->bin_size);
+
+	if (encl->fd)
+		close(encl->fd);
+
+	if (encl->segment_tbl)
+		free(encl->segment_tbl);
+
+	memset(encl, 0, sizeof(*encl));
+}
+
+static bool encl_map_bin(const char *path, struct encl *encl)
+{
+	struct stat sb;
+	void *bin;
+	int ret;
+	int fd;
+
+	fd = open(path, O_RDONLY);
+	if (fd == -1)  {
+		perror("open()");
+		return false;
+	}
+
+	ret = stat(path, &sb);
+	if (ret) {
+		perror("stat()");
+		goto err;
+	}
+
+	bin = mmap(NULL, sb.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+	if (bin == MAP_FAILED) {
+		perror("mmap()");
+		goto err;
+	}
+
+	encl->bin = bin;
+	encl->bin_size = sb.st_size;
+
+	close(fd);
+	return true;
+
+err:
+	close(fd);
+	return false;
+}
+
+static bool encl_ioc_create(struct encl *encl)
+{
+	struct sgx_secs *secs = &encl->secs;
+	struct sgx_enclave_create ioc;
+	int rc;
+
+	assert(encl->encl_base != 0);
+
+	memset(secs, 0, sizeof(*secs));
+	secs->ssa_frame_size = 1;
+	secs->attributes = SGX_ATTR_MODE64BIT;
+	secs->xfrm = 3;
+	secs->base = encl->encl_base;
+	secs->size = encl->encl_size;
+
+	ioc.src = (unsigned long)secs;
+	rc = ioctl(encl->fd, SGX_IOC_ENCLAVE_CREATE, &ioc);
+	if (rc) {
+		fprintf(stderr, "SGX_IOC_ENCLAVE_CREATE failed: errno=%d\n",
+			errno);
+		munmap((void *)secs->base, encl->encl_size);
+		return false;
+	}
+
+	return true;
+}
+
+static bool encl_ioc_add_pages(struct encl *encl, struct encl_segment *seg)
+{
+	struct sgx_enclave_add_pages ioc;
+	struct sgx_secinfo secinfo;
+	int rc;
+
+	memset(&secinfo, 0, sizeof(secinfo));
+	secinfo.flags = seg->flags;
+
+	ioc.src = (uint64_t)encl->src + seg->offset;
+	ioc.offset = seg->offset;
+	ioc.length = seg->size;
+	ioc.secinfo = (unsigned long)&secinfo;
+	ioc.flags = SGX_PAGE_MEASURE;
+
+	rc = ioctl(encl->fd, SGX_IOC_ENCLAVE_ADD_PAGES, &ioc);
+	if (rc) {
+		fprintf(stderr, "SGX_IOC_ENCLAVE_ADD_PAGES failed: errno=%d.\n",
+			errno);
+		return false;
+	}
+
+	if (ioc.count != ioc.length) {
+		fprintf(stderr, "A segment not fully processed.\n");
+		return false;
+	}
+
+	return true;
+}
+
+bool encl_load(const char *path, struct encl *encl)
+{
+	Elf64_Phdr *phdr_tbl;
+	off_t src_offset;
+	Elf64_Ehdr *ehdr;
+	int i, j;
+	int ret;
+
+	memset(encl, 0, sizeof(*encl));
+
+	ret = open("/dev/sgx/enclave", O_RDWR);
+	if (ret < 0) {
+		fprintf(stderr, "Unable to open /dev/sgx\n");
+		goto err;
+	}
+
+	encl->fd = ret;
+
+	if (!encl_map_bin(path, encl))
+		goto err;
+
+	ehdr = encl->bin;
+	phdr_tbl = encl->bin + ehdr->e_phoff;
+
+	for (i = 0; i < ehdr->e_phnum; i++) {
+		Elf64_Phdr *phdr = &phdr_tbl[i];
+
+		if (phdr->p_type == PT_LOAD)
+			encl->nr_segments++;
+	}
+
+	encl->segment_tbl = calloc(encl->nr_segments,
+				   sizeof(struct encl_segment));
+	if (!encl->segment_tbl)
+		goto err;
+
+	for (i = 0, j = 0; i < ehdr->e_phnum; i++) {
+		Elf64_Phdr *phdr = &phdr_tbl[i];
+		unsigned int flags = phdr->p_flags;
+		struct encl_segment *seg;
+
+		if (phdr->p_type != PT_LOAD)
+			continue;
+
+		seg = &encl->segment_tbl[j];
+
+		if (!!(flags & ~(PF_R | PF_W | PF_X))) {
+			fprintf(stderr,
+				"%d has invalid segment flags 0x%02x.\n", i,
+				phdr->p_flags);
+			goto err;
+		}
+
+		if (j == 0 && flags != (PF_R | PF_W)) {
+			fprintf(stderr,
+				"TCS has invalid segment flags 0x%02x.\n",
+				phdr->p_flags);
+			goto err;
+		}
+
+		if (j == 0) {
+			src_offset = (phdr->p_offset & PAGE_MASK) - src_offset;
+
+			seg->prot = PROT_READ | PROT_WRITE;
+			seg->flags = SGX_PAGE_TYPE_TCS << 8;
+		} else  {
+			seg->prot = (phdr->p_flags & PF_R) ? PROT_READ : 0;
+			seg->prot |= (phdr->p_flags & PF_W) ? PROT_WRITE : 0;
+			seg->prot |= (phdr->p_flags & PF_X) ? PROT_EXEC : 0;
+			seg->flags = (SGX_PAGE_TYPE_REG << 8) | seg->prot;
+		}
+
+		seg->offset = (phdr->p_offset & PAGE_MASK) - src_offset;
+		seg->size = (phdr->p_filesz + PAGE_SIZE - 1) & PAGE_MASK;
+
+		printf("0x%016lx 0x%016lx 0x%02x\n", seg->offset, seg->size,
+		       seg->prot);
+
+		j++;
+	}
+
+	assert(j == encl->nr_segments);
+
+	encl->src = encl->bin + src_offset;
+	encl->src_size = encl->segment_tbl[j - 1].offset +
+			 encl->segment_tbl[j - 1].size;
+
+	for (encl->encl_size = 4096; encl->encl_size < encl->src_size; )
+		encl->encl_size <<= 1;
+
+	return true;
+
+err:
+	encl_delete(encl);
+	return false;
+}
+
+static bool encl_map_area(struct encl *encl)
+{
+	size_t encl_size = encl->encl_size;
+	void *area;
+
+	area = mmap(NULL, encl_size * 2, PROT_NONE,
+		    MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+	if (area == MAP_FAILED) {
+		perror("mmap");
+		return false;
+	}
+
+	encl->encl_base = ((uint64_t)area + encl_size - 1) & ~(encl_size - 1);
+
+	munmap(area, encl->encl_base - (uint64_t)area);
+	munmap((void *)(encl->encl_base + encl_size),
+	       (uint64_t)area + encl_size - encl->encl_base);
+
+	return true;
+}
+
+bool encl_build(struct encl *encl)
+{
+	struct sgx_enclave_init ioc;
+	int ret;
+	int i;
+
+	if (!encl_map_area(encl))
+		return false;
+
+	if (!encl_ioc_create(encl))
+		return false;
+
+	/*
+	 * Pages must be added before mapping VMAs because their permissions
+	 * cap the VMA permissions.
+	 */
+	for (i = 0; i < encl->nr_segments; i++) {
+		struct encl_segment *seg = &encl->segment_tbl[i];
+
+		if (!encl_ioc_add_pages(encl, seg))
+			return false;
+	}
+
+	ioc.sigstruct = (uint64_t)&encl->sigstruct;
+	ret = ioctl(encl->fd, SGX_IOC_ENCLAVE_INIT, &ioc);
+	if (ret) {
+		fprintf(stderr, "SGX_IOC_ENCLAVE_INIT failed: errno=%d\n",
+			errno);
+		return false;
+	}
+
+	return true;
+}
diff --git a/tools/testing/selftests/sgx/main.c b/tools/testing/selftests/sgx/main.c
new file mode 100644
index 000000000000..5394b2f6af8e
--- /dev/null
+++ b/tools/testing/selftests/sgx/main.c
@@ -0,0 +1,199 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-18 Intel Corporation.
+
+#include <elf.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include "defines.h"
+#include "main.h"
+
+static const uint64_t MAGIC = 0x1122334455667788ULL;
+vdso_sgx_enter_enclave_t eenter;
+
+struct vdso_symtab {
+	Elf64_Sym *elf_symtab;
+	const char *elf_symstrtab;
+	Elf64_Word *elf_hashtab;
+};
+
+static void *vdso_get_base_addr(char *envp[])
+{
+	Elf64_auxv_t *auxv;
+	int i;
+
+	for (i = 0; envp[i]; i++)
+		;
+
+	auxv = (Elf64_auxv_t *)&envp[i + 1];
+
+	for (i = 0; auxv[i].a_type != AT_NULL; i++) {
+		if (auxv[i].a_type == AT_SYSINFO_EHDR)
+			return (void *)auxv[i].a_un.a_val;
+	}
+
+	return NULL;
+}
+
+static Elf64_Dyn *vdso_get_dyntab(void *addr)
+{
+	Elf64_Ehdr *ehdr = addr;
+	Elf64_Phdr *phdrtab = addr + ehdr->e_phoff;
+	int i;
+
+	for (i = 0; i < ehdr->e_phnum; i++)
+		if (phdrtab[i].p_type == PT_DYNAMIC)
+			return addr + phdrtab[i].p_offset;
+
+	return NULL;
+}
+
+static void *vdso_get_dyn(void *addr, Elf64_Dyn *dyntab, Elf64_Sxword tag)
+{
+	int i;
+
+	for (i = 0; dyntab[i].d_tag != DT_NULL; i++)
+		if (dyntab[i].d_tag == tag)
+			return addr + dyntab[i].d_un.d_ptr;
+
+	return NULL;
+}
+
+static bool vdso_get_symtab(void *addr, struct vdso_symtab *symtab)
+{
+	Elf64_Dyn *dyntab = vdso_get_dyntab(addr);
+
+	symtab->elf_symtab = vdso_get_dyn(addr, dyntab, DT_SYMTAB);
+	if (!symtab->elf_symtab)
+		return false;
+
+	symtab->elf_symstrtab = vdso_get_dyn(addr, dyntab, DT_STRTAB);
+	if (!symtab->elf_symstrtab)
+		return false;
+
+	symtab->elf_hashtab = vdso_get_dyn(addr, dyntab, DT_HASH);
+	if (!symtab->elf_hashtab)
+		return false;
+
+	return true;
+}
+
+static unsigned long elf_sym_hash(const char *name)
+{
+	unsigned long h = 0, high;
+
+	while (*name) {
+		h = (h << 4) + *name++;
+		high = h & 0xf0000000;
+
+		if (high)
+			h ^= high >> 24;
+
+		h &= ~high;
+	}
+
+	return h;
+}
+
+static Elf64_Sym *vdso_symtab_get(struct vdso_symtab *symtab, const char *name)
+{
+	Elf64_Word bucketnum = symtab->elf_hashtab[0];
+	Elf64_Word *buckettab = &symtab->elf_hashtab[2];
+	Elf64_Word *chaintab = &symtab->elf_hashtab[2 + bucketnum];
+	Elf64_Sym *sym;
+	Elf64_Word i;
+
+	for (i = buckettab[elf_sym_hash(name) % bucketnum]; i != STN_UNDEF;
+	     i = chaintab[i]) {
+		sym = &symtab->elf_symtab[i];
+		if (!strcmp(name, &symtab->elf_symstrtab[sym->st_name]))
+			return sym;
+	}
+
+	return NULL;
+}
+
+int main(int argc, char *argv[], char *envp[])
+{
+	struct sgx_enclave_exception exception;
+	struct vdso_symtab symtab;
+	Elf64_Sym *eenter_sym;
+	uint64_t result = 0;
+	struct encl encl;
+	unsigned int i;
+	void *addr;
+
+	if (!encl_load("test_encl.elf", &encl))
+		goto err;
+
+	if (!encl_measure(&encl))
+		goto err;
+
+	if (!encl_build(&encl))
+		goto err;
+
+	/*
+	 * An enclave consumer only must do this.
+	 */
+	for (i = 0; i < encl.nr_segments; i++) {
+		struct encl_segment *seg = &encl.segment_tbl[i];
+
+		addr = mmap((void *)encl.encl_base + seg->offset, seg->size,
+			    seg->prot, MAP_SHARED | MAP_FIXED, encl.fd, 0);
+		if (addr == MAP_FAILED) {
+			fprintf(stderr, "mmap() failed, errno=%d.\n", errno);
+			return false;
+		}
+	}
+
+	memset(&exception, 0, sizeof(exception));
+
+	addr = vdso_get_base_addr(envp);
+	if (!addr)
+		goto err;
+
+	if (!vdso_get_symtab(addr, &symtab))
+		goto err;
+
+	eenter_sym = vdso_symtab_get(&symtab, "__vdso_sgx_enter_enclave");
+	if (!eenter_sym)
+		goto err;
+
+	eenter = addr + eenter_sym->st_value;
+
+	sgx_call_vdso((void *)&MAGIC, &result, 0, EENTER, NULL, NULL,
+		      (void *)encl.encl_base, &exception, NULL);
+	if (result != MAGIC) {
+		printf("FAIL: sgx_call_vdso(), expected: 0x%lx, got: 0x%lx\n",
+		       MAGIC, result);
+		goto err;
+	}
+
+	/* Invoke the vDSO directly. */
+	result = 0;
+	eenter((unsigned long)&MAGIC, (unsigned long)&result, 0, EENTER, 0, 0,
+	       (void *)encl.encl_base, &exception, NULL);
+	if (result != MAGIC) {
+		printf("FAIL: eenter(), expected: 0x%lx, got: 0x%lx\n",
+		       MAGIC, result);
+		goto err;
+	}
+
+	printf("SUCCESS\n");
+	encl_delete(&encl);
+	exit(0);
+
+err:
+	encl_delete(&encl);
+	exit(1);
+}
diff --git a/tools/testing/selftests/sgx/main.h b/tools/testing/selftests/sgx/main.h
new file mode 100644
index 000000000000..999422cc7343
--- /dev/null
+++ b/tools/testing/selftests/sgx/main.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright(c) 2016-19 Intel Corporation.
+ */
+
+#ifndef MAIN_H
+#define MAIN_H
+
+struct encl_segment {
+	off_t offset;
+	size_t size;
+	unsigned int prot;
+	unsigned int flags;
+};
+
+struct encl {
+	int fd;
+	void *bin;
+	off_t bin_size;
+	void *src;
+	size_t src_size;
+	size_t encl_size;
+	off_t encl_base;
+	unsigned int nr_segments;
+	struct encl_segment *segment_tbl;
+	struct sgx_secs secs;
+	struct sgx_sigstruct sigstruct;
+};
+
+void encl_delete(struct encl *ctx);
+bool encl_load(const char *path, struct encl *encl);
+bool encl_measure(struct encl *encl);
+bool encl_build(struct encl *encl);
+
+int sgx_call_vdso(void *rdi, void *rsi, long rdx, u32 leaf, void *r8, void *r9,
+		  void *tcs, struct sgx_enclave_exception *ei, void *cb);
+
+#endif /* MAIN_H */
diff --git a/tools/testing/selftests/sgx/sigstruct.c b/tools/testing/selftests/sgx/sigstruct.c
new file mode 100644
index 000000000000..ceddad478672
--- /dev/null
+++ b/tools/testing/selftests/sgx/sigstruct.c
@@ -0,0 +1,395 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-18 Intel Corporation.
+
+#define _GNU_SOURCE
+#include <assert.h>
+#include <getopt.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <openssl/err.h>
+#include <openssl/pem.h>
+#include "defines.h"
+#include "main.h"
+
+struct q1q2_ctx {
+	BN_CTX *bn_ctx;
+	BIGNUM *m;
+	BIGNUM *s;
+	BIGNUM *q1;
+	BIGNUM *qr;
+	BIGNUM *q2;
+};
+
+static void free_q1q2_ctx(struct q1q2_ctx *ctx)
+{
+	BN_CTX_free(ctx->bn_ctx);
+	BN_free(ctx->m);
+	BN_free(ctx->s);
+	BN_free(ctx->q1);
+	BN_free(ctx->qr);
+	BN_free(ctx->q2);
+}
+
+static bool alloc_q1q2_ctx(const uint8_t *s, const uint8_t *m,
+			   struct q1q2_ctx *ctx)
+{
+	ctx->bn_ctx = BN_CTX_new();
+	ctx->s = BN_bin2bn(s, SGX_MODULUS_SIZE, NULL);
+	ctx->m = BN_bin2bn(m, SGX_MODULUS_SIZE, NULL);
+	ctx->q1 = BN_new();
+	ctx->qr = BN_new();
+	ctx->q2 = BN_new();
+
+	if (!ctx->bn_ctx || !ctx->s || !ctx->m || !ctx->q1 || !ctx->qr ||
+	    !ctx->q2) {
+		free_q1q2_ctx(ctx);
+		return false;
+	}
+
+	return true;
+}
+
+static bool calc_q1q2(const uint8_t *s, const uint8_t *m, uint8_t *q1,
+		      uint8_t *q2)
+{
+	struct q1q2_ctx ctx;
+
+	if (!alloc_q1q2_ctx(s, m, &ctx)) {
+		fprintf(stderr, "Not enough memory for Q1Q2 calculation\n");
+		return false;
+	}
+
+	if (!BN_mul(ctx.q1, ctx.s, ctx.s, ctx.bn_ctx))
+		goto out;
+
+	if (!BN_div(ctx.q1, ctx.qr, ctx.q1, ctx.m, ctx.bn_ctx))
+		goto out;
+
+	if (BN_num_bytes(ctx.q1) > SGX_MODULUS_SIZE) {
+		fprintf(stderr, "Too large Q1 %d bytes\n",
+			BN_num_bytes(ctx.q1));
+		goto out;
+	}
+
+	if (!BN_mul(ctx.q2, ctx.s, ctx.qr, ctx.bn_ctx))
+		goto out;
+
+	if (!BN_div(ctx.q2, NULL, ctx.q2, ctx.m, ctx.bn_ctx))
+		goto out;
+
+	if (BN_num_bytes(ctx.q2) > SGX_MODULUS_SIZE) {
+		fprintf(stderr, "Too large Q2 %d bytes\n",
+			BN_num_bytes(ctx.q2));
+		goto out;
+	}
+
+	BN_bn2bin(ctx.q1, q1);
+	BN_bn2bin(ctx.q2, q2);
+
+	free_q1q2_ctx(&ctx);
+	return true;
+out:
+	free_q1q2_ctx(&ctx);
+	return false;
+}
+
+struct sgx_sigstruct_payload {
+	struct sgx_sigstruct_header header;
+	struct sgx_sigstruct_body body;
+};
+
+static bool check_crypto_errors(void)
+{
+	int err;
+	bool had_errors = false;
+	const char *filename;
+	int line;
+	char str[256];
+
+	for ( ; ; ) {
+		if (ERR_peek_error() == 0)
+			break;
+
+		had_errors = true;
+		err = ERR_get_error_line(&filename, &line);
+		ERR_error_string_n(err, str, sizeof(str));
+		fprintf(stderr, "crypto: %s: %s:%d\n", str, filename, line);
+	}
+
+	return had_errors;
+}
+
+static inline const BIGNUM *get_modulus(RSA *key)
+{
+#if OPENSSL_VERSION_NUMBER < 0x10100000L
+	return key->n;
+#else
+	const BIGNUM *n;
+
+	RSA_get0_key(key, &n, NULL, NULL);
+	return n;
+#endif
+}
+
+static RSA *gen_sign_key(void)
+{
+	BIGNUM *e;
+	RSA *key;
+	int ret;
+
+	e = BN_new();
+	key = RSA_new();
+
+	if (!e || !key)
+		goto err;
+
+	ret = BN_set_word(e, RSA_3);
+	if (ret != 1)
+		goto err;
+
+	ret = RSA_generate_key_ex(key, 3072, e, NULL);
+	if (ret != 1)
+		goto err;
+
+	BN_free(e);
+
+	return key;
+
+err:
+	RSA_free(key);
+	BN_free(e);
+
+	return NULL;
+}
+
+static void reverse_bytes(void *data, int length)
+{
+	int i = 0;
+	int j = length - 1;
+	uint8_t temp;
+	uint8_t *ptr = data;
+
+	while (i < j) {
+		temp = ptr[i];
+		ptr[i] = ptr[j];
+		ptr[j] = temp;
+		i++;
+		j--;
+	}
+}
+
+enum mrtags {
+	MRECREATE = 0x0045544145524345,
+	MREADD = 0x0000000044444145,
+	MREEXTEND = 0x00444E4554584545,
+};
+
+static bool mrenclave_update(EVP_MD_CTX *ctx, const void *data)
+{
+	if (!EVP_DigestUpdate(ctx, data, 64)) {
+		fprintf(stderr, "digest update failed\n");
+		return false;
+	}
+
+	return true;
+}
+
+static bool mrenclave_commit(EVP_MD_CTX *ctx, uint8_t *mrenclave)
+{
+	unsigned int size;
+
+	if (!EVP_DigestFinal_ex(ctx, (unsigned char *)mrenclave, &size)) {
+		fprintf(stderr, "digest commit failed\n");
+		return false;
+	}
+
+	if (size != 32) {
+		fprintf(stderr, "invalid digest size = %u\n", size);
+		return false;
+	}
+
+	return true;
+}
+
+struct mrecreate {
+	uint64_t tag;
+	uint32_t ssaframesize;
+	uint64_t size;
+	uint8_t reserved[44];
+} __attribute__((__packed__));
+
+
+static bool mrenclave_ecreate(EVP_MD_CTX *ctx, uint64_t blob_size)
+{
+	struct mrecreate mrecreate;
+	uint64_t encl_size;
+
+	for (encl_size = 0x1000; encl_size < blob_size; )
+		encl_size <<= 1;
+
+	memset(&mrecreate, 0, sizeof(mrecreate));
+	mrecreate.tag = MRECREATE;
+	mrecreate.ssaframesize = 1;
+	mrecreate.size = encl_size;
+
+	if (!EVP_DigestInit_ex(ctx, EVP_sha256(), NULL))
+		return false;
+
+	return mrenclave_update(ctx, &mrecreate);
+}
+
+struct mreadd {
+	uint64_t tag;
+	uint64_t offset;
+	uint64_t flags; /* SECINFO flags */
+	uint8_t reserved[40];
+} __attribute__((__packed__));
+
+static bool mrenclave_eadd(EVP_MD_CTX *ctx, uint64_t offset, uint64_t flags)
+{
+	struct mreadd mreadd;
+
+	memset(&mreadd, 0, sizeof(mreadd));
+	mreadd.tag = MREADD;
+	mreadd.offset = offset;
+	mreadd.flags = flags;
+
+	return mrenclave_update(ctx, &mreadd);
+}
+
+struct mreextend {
+	uint64_t tag;
+	uint64_t offset;
+	uint8_t reserved[48];
+} __attribute__((__packed__));
+
+static bool mrenclave_eextend(EVP_MD_CTX *ctx, uint64_t offset,
+			      const uint8_t *data)
+{
+	struct mreextend mreextend;
+	int i;
+
+	for (i = 0; i < 0x1000; i += 0x100) {
+		memset(&mreextend, 0, sizeof(mreextend));
+		mreextend.tag = MREEXTEND;
+		mreextend.offset = offset + i;
+
+		if (!mrenclave_update(ctx, &mreextend))
+			return false;
+
+		if (!mrenclave_update(ctx, &data[i + 0x00]))
+			return false;
+
+		if (!mrenclave_update(ctx, &data[i + 0x40]))
+			return false;
+
+		if (!mrenclave_update(ctx, &data[i + 0x80]))
+			return false;
+
+		if (!mrenclave_update(ctx, &data[i + 0xC0]))
+			return false;
+	}
+
+	return true;
+}
+
+static bool mrenclave_segment(EVP_MD_CTX *ctx, struct encl *encl,
+			      struct encl_segment *seg)
+{
+	uint64_t end = seg->offset + seg->size;
+	uint64_t offset;
+
+	for (offset = seg->offset; offset < end; offset += PAGE_SIZE) {
+		if (!mrenclave_eadd(ctx, offset, seg->flags))
+			return false;
+
+		if (!mrenclave_eextend(ctx, offset, encl->src + offset))
+			return false;
+	}
+
+	return true;
+}
+
+bool encl_measure(struct encl *encl)
+{
+	uint64_t header1[2] = {0x000000E100000006, 0x0000000000010000};
+	uint64_t header2[2] = {0x0000006000000101, 0x0000000100000060};
+	struct sgx_sigstruct *sigstruct = &encl->sigstruct;
+	struct sgx_sigstruct_payload payload;
+	uint8_t digest[SHA256_DIGEST_LENGTH];
+	unsigned int siglen;
+	RSA *key = NULL;
+	EVP_MD_CTX *ctx;
+	int i;
+
+	memset(sigstruct, 0, sizeof(*sigstruct));
+
+	sigstruct->header.header1[0] = header1[0];
+	sigstruct->header.header1[1] = header1[1];
+	sigstruct->header.header2[0] = header2[0];
+	sigstruct->header.header2[1] = header2[1];
+	sigstruct->exponent = 3;
+	sigstruct->body.attributes = SGX_ATTR_MODE64BIT;
+	sigstruct->body.xfrm = 3;
+
+	/* sanity check */
+	if (check_crypto_errors())
+		goto err;
+
+	key = gen_sign_key();
+	if (!key)
+		goto err;
+
+	BN_bn2bin(get_modulus(key), sigstruct->modulus);
+
+	ctx = EVP_MD_CTX_create();
+	if (!ctx)
+		goto err;
+
+	if (!mrenclave_ecreate(ctx, encl->src_size))
+		goto err;
+
+	for (i = 0; i < encl->nr_segments; i++) {
+		struct encl_segment *seg = &encl->segment_tbl[i];
+
+		if (!mrenclave_segment(ctx, encl, seg))
+			goto err;
+	}
+
+	if (!mrenclave_commit(ctx, sigstruct->body.mrenclave))
+		goto err;
+
+	memcpy(&payload.header, &sigstruct->header, sizeof(sigstruct->header));
+	memcpy(&payload.body, &sigstruct->body, sizeof(sigstruct->body));
+
+	SHA256((unsigned char *)&payload, sizeof(payload), digest);
+
+	if (!RSA_sign(NID_sha256, digest, SHA256_DIGEST_LENGTH,
+		      sigstruct->signature, &siglen, key))
+		goto err;
+
+	if (!calc_q1q2(sigstruct->signature, sigstruct->modulus, sigstruct->q1,
+		       sigstruct->q2))
+		goto err;
+
+	/* BE -> LE */
+	reverse_bytes(sigstruct->signature, SGX_MODULUS_SIZE);
+	reverse_bytes(sigstruct->modulus, SGX_MODULUS_SIZE);
+	reverse_bytes(sigstruct->q1, SGX_MODULUS_SIZE);
+	reverse_bytes(sigstruct->q2, SGX_MODULUS_SIZE);
+
+	EVP_MD_CTX_destroy(ctx);
+	RSA_free(key);
+	return true;
+
+err:
+	EVP_MD_CTX_destroy(ctx);
+	RSA_free(key);
+	return false;
+}
diff --git a/tools/testing/selftests/sgx/test_encl.c b/tools/testing/selftests/sgx/test_encl.c
new file mode 100644
index 000000000000..ede915399742
--- /dev/null
+++ b/tools/testing/selftests/sgx/test_encl.c
@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2016-18 Intel Corporation.
+
+#include <stddef.h>
+#include "defines.h"
+
+static void *memcpy(void *dest, const void *src, size_t n)
+{
+	size_t i;
+
+	for (i = 0; i < n; i++)
+		((char *)dest)[i] = ((char *)src)[i];
+
+	return dest;
+}
+
+void encl_body(void *rdi, void *rsi)
+{
+	memcpy(rsi, rdi, 8);
+}
diff --git a/tools/testing/selftests/sgx/test_encl.lds b/tools/testing/selftests/sgx/test_encl.lds
new file mode 100644
index 000000000000..0fbbda7e665e
--- /dev/null
+++ b/tools/testing/selftests/sgx/test_encl.lds
@@ -0,0 +1,40 @@
+OUTPUT_FORMAT(elf64-x86-64)
+
+PHDRS
+{
+	tcs PT_LOAD;
+	text PT_LOAD;
+	data PT_LOAD;
+}
+
+SECTIONS
+{
+	. = 0;
+	.tcs : {
+		*(.tcs*)
+	} : tcs
+
+	. = ALIGN(4096);
+	.text : {
+		*(.text*)
+		*(.rodata*)
+	} : text
+
+	. = ALIGN(4096);
+	.data : {
+		*(.data*)
+	} : data
+
+	/DISCARD/ : {
+		*(.comment*)
+		*(.note*)
+		*(.debug*)
+		*(.eh_frame*)
+	}
+}
+
+ASSERT(!DEFINED(.altinstructions), "ALTERNATIVES are not supported in enclaves")
+ASSERT(!DEFINED(.altinstr_replacement), "ALTERNATIVES are not supported in enclaves")
+ASSERT(!DEFINED(.discard.retpoline_safe), "RETPOLINE ALTERNATIVES are not supported in enclaves")
+ASSERT(!DEFINED(.discard.nospec), "RETPOLINE ALTERNATIVES are not supported in enclaves")
+ASSERT(!DEFINED(.got.plt), "Libcalls are not supported in enclaves")
diff --git a/tools/testing/selftests/sgx/test_encl_bootstrap.S b/tools/testing/selftests/sgx/test_encl_bootstrap.S
new file mode 100644
index 000000000000..6836ea86126e
--- /dev/null
+++ b/tools/testing/selftests/sgx/test_encl_bootstrap.S
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
+/*
+ * Copyright(c) 2016-18 Intel Corporation.
+ */
+
+	.macro ENCLU
+	.byte 0x0f, 0x01, 0xd7
+	.endm
+
+	.section ".tcs", "aw"
+	.balign	4096
+
+	.fill	1, 8, 0			# STATE (set by CPU)
+	.fill	1, 8, 0			# FLAGS
+	.quad	encl_ssa		# OSSA
+	.fill	1, 4, 0			# CSSA (set by CPU)
+	.fill	1, 4, 1			# NSSA
+	.quad	encl_entry		# OENTRY
+	.fill	1, 8, 0			# AEP (set by EENTER and ERESUME)
+	.fill	1, 8, 0			# OFSBASE
+	.fill	1, 8, 0			# OGSBASE
+	.fill	1, 4, 0xFFFFFFFF 	# FSLIMIT
+	.fill	1, 4, 0xFFFFFFFF	# GSLIMIT
+	.fill	4024, 1, 0		# Reserved
+
+	# Identical to the previous TCS.
+	.fill	1, 8, 0			# STATE (set by CPU)
+	.fill	1, 8, 0			# FLAGS
+	.quad	encl_ssa		# OSSA
+	.fill	1, 4, 0			# CSSA (set by CPU)
+	.fill	1, 4, 1			# NSSA
+	.quad	encl_entry		# OENTRY
+	.fill	1, 8, 0			# AEP (set by EENTER and ERESUME)
+	.fill	1, 8, 0			# OFSBASE
+	.fill	1, 8, 0			# OGSBASE
+	.fill	1, 4, 0xFFFFFFFF 	# FSLIMIT
+	.fill	1, 4, 0xFFFFFFFF	# GSLIMIT
+	.fill	4024, 1, 0		# Reserved
+
+	.text
+
+encl_entry:
+	# RBX contains the base address for TCS, which is also the first address
+	# inside the enclave. By adding the value of le_stack_end to it, we get
+	# the absolute address for the stack.
+	lea	(encl_stack)(%rbx), %rax
+	xchg	%rsp, %rax
+	push	%rax
+
+	push	%rcx # push the address after EENTER
+	push	%rbx # push the enclave base address
+
+	call	encl_body
+
+	pop	%rbx # pop the enclave base address
+
+	/* Clear volatile GPRs, except RAX (EEXIT leaf). */
+	xor     %rcx, %rcx
+	xor     %rdx, %rdx
+	xor     %rdi, %rdi
+	xor     %rsi, %rsi
+	xor     %r8, %r8
+	xor     %r9, %r9
+	xor     %r10, %r10
+	xor     %r11, %r11
+
+	# Reset status flags.
+	add     %rdx, %rdx # OF = SF = AF = CF = 0; ZF = PF = 1
+
+	# Prepare EEXIT target by popping the address of the instruction after
+	# EENTER to RBX.
+	pop	%rbx
+
+	# Restore the caller stack.
+	pop	%rax
+	mov	%rax, %rsp
+
+	# EEXIT
+	mov	$4, %rax
+	enclu
+
+	.section ".data", "aw"
+
+encl_ssa:
+	.space 4096
+
+	.balign 4096
+	.space 8192
+encl_stack:
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH v30 19/20] docs: x86/sgx: Document SGX micro architecture and kernel internals
  2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
                   ` (17 preceding siblings ...)
  2020-05-15  0:44 ` [PATCH v30 18/20] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
@ 2020-05-15  0:44 ` Jarkko Sakkinen
  2020-05-15  0:44 ` [PATCH v30 20/20] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
  2020-05-16  8:57 ` [PATCH] x86/cpu/intel: Add nosgx kernel parameter Jarkko Sakkinen
  20 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-15  0:44 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: akpm, dave.hansen, sean.j.christopherson, nhorman, npmccallum,
	haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp, josh, luto,
	kai.huang, rientjes, cedric.xing, puiterwijk, Jarkko Sakkinen,
	linux-doc, Randy Dunlap


[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #0: Type: text/plain; charset=y, Size: 9760 bytes --]

Document the Intel SGX kernel architecture. The fine-grained micro
architecture details can be looked up from Intel SDM Volume 3D.

Cc: linux-doc@vger.kernel.org
Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 Documentation/x86/index.rst |   1 +
 Documentation/x86/sgx.rst   | 206 ++++++++++++++++++++++++++++++++++++
 2 files changed, 207 insertions(+)
 create mode 100644 Documentation/x86/sgx.rst

diff --git a/Documentation/x86/index.rst b/Documentation/x86/index.rst
index 265d9e9a093b..807290bf357c 100644
--- a/Documentation/x86/index.rst
+++ b/Documentation/x86/index.rst
@@ -30,3 +30,4 @@ x86-specific Documentation
    usb-legacy-support
    i386/index
    x86_64/index
+   sgx
diff --git a/Documentation/x86/sgx.rst b/Documentation/x86/sgx.rst
new file mode 100644
index 000000000000..9609a3409ad1
--- /dev/null
+++ b/Documentation/x86/sgx.rst
@@ -0,0 +1,206 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+============
+Architecture
+============
+
+*Software Guard eXtensions (SGX)* is a set of instructions that enable ring-3
+applications to set aside private regions of code and data. These regions are
+called enclaves. An enclave can be entered to a fixed set of entry points. Only
+a CPU running inside the enclave can access its code and data.
+
+The support can be determined by
+
+	``grep sgx /proc/cpuinfo``
+
+Enclave Page Cache
+==================
+
+SGX utilizes an *Enclave Page Cache (EPC)* to store pages that are associated
+with an enclave. It is contained in a BIOS reserved region of physical memory.
+Unlike pages used for regular memory, pages can only be accessed outside the
+enclave for different purposes with the instructions **ENCLS**, **ENCLV** and
+**ENCLU**.
+
+Direct memory accesses to an enclave can be only done by a CPU executing inside
+the enclave. An enclave can be entered with **ENCLU[EENTER]** to a fixed set of
+entry points. However, a CPU executing inside the enclave can do outside memory
+accesses.
+
+Page Types
+----------
+
+**SGX Enclave Control Structure (SECS)**
+   Enclave's address range, attributes and other global data are defined
+   by this structure.
+
+**Regular (REG)**
+   Regular EPC pages contain the code and data of an enclave.
+
+**Thread Control Structure (TCS)**
+   Thread Control Structure pages define the entry points to an enclave and
+   track the execution state of an enclave thread.
+
+**Version Array (VA)**
+   Version Array pages contain 512 slots, each of which can contain a version
+   number for a page evicted from the EPC.
+
+Enclave Page Cache Map
+----------------------
+
+The processor tracks EPC pages via the *Enclave Page Cache Map (EPCM)*.  EPCM
+contains an entry for each EPC page, which describes the owning enclave, access
+rights and page type among the other things.
+
+The permissions from EPCM is consulted if and only if walking the kernel page
+tables succeeds. The total permissions are thus a conjunction between page table
+and EPCM permissions.
+
+For all intents and purposes the SGX architecture allows the processor to
+invalidate all EPCM entries at will, i.e. requires that software be prepared to
+handle an EPCM fault at any time. The contents of EPC are encrypted with an
+ephemeral key, which is lost on power transitions.
+
+EPC management
+==============
+
+EPC pages do not have ``struct page`` instances. They are IO memory from kernel
+perspective. The consequence is that they are always mapped as shared memory.
+Kernel defines ``/dev/sgx/enclave`` that can be mapped as ``MAP_SHARED`` to
+define the address range for an enclave.
+
+EPC Over-subscription
+=====================
+
+When the amount of free EPC pages goes below a low watermark the swapping thread
+starts reclaiming pages. The pages that do not have the **A** bit set are
+selected as victim pages.
+
+Launch Control
+==============
+
+SGX provides a launch control mechanism. After all enclave pages have been
+copied, kernel executes **ENCLS[EINIT]**, which initializes the enclave. Only
+after this the CPU can execute inside the enclave.
+
+This leaf function takes an RSA-3072 signature of the enclave measurement and an
+optional cryptographic token. Linux does not take advantage of launch tokens.
+The instruction checks that the signature is signed with the key defined in
+**IA32_SGXLEPUBKEYHASH?** MSRs and the measurement is correct. If so, the
+enclave is allowed to be executed.
+
+MSRs can be configured by the BIOS to be either readable or writable. Linux
+supports only writable configuration in order to give full control to the kernel
+on launch control policy. Readable configuration requires the use of previously
+mentioned launch tokens.
+
+The current kernel implementation supports only writable MSRs. The launch is
+performed by setting the MSRs to the hash of the enclave signer's public key.
+The alternative would be to have *a launch enclave* that would be signed with
+the key set into MSRs, which would then generate launch tokens for other
+enclaves. This would only make sense with read-only MSRs, and thus the option
+has been discarded.
+
+Attestation
+===========
+
+Local Attestation
+-----------------
+
+In local attestation an enclave creates a **REPORT** data structure with
+**ENCLS[EREPORT]**, which describes the origin of an enclave. In particular, it
+contains a AES-CMAC of the enclave contents signed with a report key unique to
+each processor. All enclaves have access to this key.
+
+This mechanism can also be used in addition as a communication channel as the
+**REPORT** data structure includes a 64-byte field for variable information.
+
+Remote Attestation
+------------------
+
+For remote attestation (or provisioning) there are schemes available:
+
+* EPID scheme, which requires the use of Intel managed attestation service.
+* ECDSA scheme, which allows a 3rd party to act as an attestation service.
+
+Intel has released an open source *Quoting Enclave (QE)* and *Provisioning
+Certification Enclave (PCE)* for the ECDSA based scheme. A PCE is used to
+certify the locally used QE's.
+
+Intel also provides a proprietary of the PCE. This is a necessary when one
+needs to be able to prove that an enclave is running on real hardware. To
+achieve this the enclave needs to be rooted to the Intel's PKI, which obviously
+cannot be exposed to 3rd parties.
+
+Both schemes require **ATTRIBUTES.PROVISIONKEY** but only EPID scheme uses the
+on-die provisioning key. This privilege should be under normal conditions given
+only to QE's because uncontrolled use of attestation could be used by malware
+for benefit.
+
+Encryption engines
+==================
+
+In order to conceal the enclave data while it is out of the CPU package,
+memory controller has to be extended with an encryption engine. MC can then
+route incoming requests coming from CPU cores running in enclave mode to the
+encryption engine.
+
+In CPUs prior to Icelake, Memory Encryption Engine (MEE) is used to
+encrypt pages leaving the CPU caches. MEE uses a n-ary Merkle tree with root in
+SRAM to maintain integrity of the encrypted data. This provides integrity and
+anti-replay protection but does not scale to large memory sizes because the time
+required to update the Merkle tree grows logarithmically in relation to the
+memory size.
+
+CPUs starting from Icelake use Total Memory Encryption (TME) in the place of
+MEE. TME throws away the Merkle tree, which means losing integrity and
+anti-replay protection but also enables variable size memory pools for EPC.
+Using this attack for benefit would require an interposer on the system bus.
+
+Backing storage
+===============
+
+Backing storage is shared and not accounted. It is implemented as a private
+shmem file. Providing a backing storage in some form from user space is not
+possible - accounting would go to invalid state as reclaimed pages would get
+accounted to the processes of which behalf the kernel happened to be acting on.
+
+Access control
+==============
+
+`mmap()` permissions are capped by the enclave permissions. A direct
+consequence of this is that all the pages for an address range must be added
+before `mmap()` can be applied. Effectively an enclave page with minimum
+permission in the address range sets the permission cap for the mapping
+operation.
+
+Usage Models
+============
+
+Shared Library
+--------------
+
+Sensitive data and the code that acts on it is partitioned from the application
+into a separate library. The library is then linked as a DSO which can be loaded
+into an enclave. The application can then make individual function calls into
+the enclave through special SGX instructions. A run-time within the enclave is
+configured to marshal function parameters into and out of the enclave and to
+call the correct library function.
+
+Application Container
+---------------------
+
+An application may be loaded into a container enclave which is specially
+configured with a library OS and run-time which permits the application to run.
+The enclave run-time and library OS work together to execute the application
+when a thread enters the enclave.
+
+References
+==========
+
+"Intel® Software Guard Extensions: EPID Provisioning and Attestation Services"
+   https://software.intel.com/sites/default/files/managed/57/0e/ww10-2016-sgx-provisioning-and-attestation-final.pdf
+
+"Supporting Third Party Attestation for Intel® SGX with Intel® Data Center
+Attestation Primitives"
+   https://software.intel.com/sites/default/files/managed/f1/b8/intel-sgx-support-for-third-party-attestation.pdf
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH v30 20/20] x86/sgx: Update MAINTAINERS
  2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
                   ` (18 preceding siblings ...)
  2020-05-15  0:44 ` [PATCH v30 19/20] docs: x86/sgx: Document SGX micro architecture and kernel internals Jarkko Sakkinen
@ 2020-05-15  0:44 ` Jarkko Sakkinen
  2020-05-16  8:57 ` [PATCH] x86/cpu/intel: Add nosgx kernel parameter Jarkko Sakkinen
  20 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-15  0:44 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: akpm, dave.hansen, sean.j.christopherson, nhorman, npmccallum,
	haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp, josh, luto,
	kai.huang, rientjes, cedric.xing, puiterwijk, Jarkko Sakkinen

Add the maintainer information for the SGX subsystem.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 MAINTAINERS | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 091ec22c1a23..cdebc57f9901 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8840,6 +8840,17 @@ F:	Documentation/x86/intel_txt.rst
 F:	arch/x86/kernel/tboot.c
 F:	include/linux/tboot.h
 
+INTEL SGX
+M:	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
+M:	Sean Christopherson <sean.j.christopherson@intel.com>
+L:	linux-sgx@vger.kernel.org
+S:	Maintained
+Q:	https://patchwork.kernel.org/project/intel-sgx/list/
+T:	git https://github.com/jsakkine-intel/linux-sgx.git
+F:	arch/x86/include/uapi/asm/sgx.h
+F:	arch/x86/kernel/cpu/sgx/*
+K:	\bSGX_
+
 INTERCONNECT API
 M:	Georgi Djakov <georgi.djakov@linaro.org>
 L:	linux-pm@vger.kernel.org
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH] x86/cpu/intel: Add nosgx kernel parameter
  2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
                   ` (19 preceding siblings ...)
  2020-05-15  0:44 ` [PATCH v30 20/20] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
@ 2020-05-16  8:57 ` Jarkko Sakkinen
  20 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-16  8:57 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: Jarkko Sakkinen, Sean Christopherson, akpm, andriy.shevchenko,
	asapek, bp, cedric.xing, chenalexchen, conradparker, cyhanish,
	dave.hansen, haitao.huang, josh, kai.huang, kai.svahn, kmoy,
	ludloff, luto, nhorman, npmccallum, puiterwijk, rientjes, tglx,
	yaozhangx

Add kernel parameter to disable Intel SGX kernel support.

Tested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 Documentation/admin-guide/kernel-parameters.txt | 2 ++
 arch/x86/kernel/cpu/feat_ctl.c                  | 9 +++++++++
 2 files changed, 11 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 7bc83f3d9bdf..9f7202a54db6 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3268,6 +3268,8 @@
 
 	nosep		[BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
 
+	nosgx		[X86-64,SGX] Disables Intel SGX kernel support.
+
 	nosmp		[SMP] Tells an SMP kernel to act as a UP kernel,
 			and disable the IO APIC.  legacy for "maxcpus=0".
 
diff --git a/arch/x86/kernel/cpu/feat_ctl.c b/arch/x86/kernel/cpu/feat_ctl.c
index c3afcd2e4342..1837df39527f 100644
--- a/arch/x86/kernel/cpu/feat_ctl.c
+++ b/arch/x86/kernel/cpu/feat_ctl.c
@@ -101,6 +101,15 @@ static void clear_sgx_caps(void)
 	setup_clear_cpu_cap(X86_FEATURE_SGX2);
 }
 
+static int __init nosgx(char *str)
+{
+	clear_sgx_caps();
+
+	return 0;
+}
+
+early_param("nosgx", nosgx);
+
 void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
 {
 	bool tboot = tboot_enabled();
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 01/20] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits
  2020-05-15  0:43 ` [PATCH v30 01/20] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
@ 2020-05-20 12:16   ` Borislav Petkov
  2020-05-20 14:00     ` Jarkko Sakkinen
  0 siblings, 1 reply; 76+ messages in thread
From: Borislav Petkov @ 2020-05-20 12:16 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	sean.j.christopherson, nhorman, npmccallum, haitao.huang,
	andriy.shevchenko, tglx, kai.svahn, josh, luto, kai.huang,
	rientjes, cedric.xing, puiterwijk, Jethro Beekman

On Fri, May 15, 2020 at 03:43:51AM +0300, Jarkko Sakkinen wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
> 
> Add X86_FEATURE_SGX from CPUID.(EAX=7, ECX=1), which informs whether the
> CPU has SGX.
> 
> Add X86_FEATURE_SGX1 and X86_FEATURE_SGX2 from CPUID.(EAX=12H, ECX=0),
> which describe the level of SGX support available [1].
> 
> Remap CPUID.(EAX=12H, ECX=0) bits to the Linux fake CPUID 8 in order to
> conserve some space. Keep the bit positions intact because KVM requires
> this. Reserve bits 0-7 for SGX in order to maintain this invariant also
> when new SGX specific feature bits get added.

That paragraph needs dropping now.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 02/20] x86/cpufeatures: x86/msr: Intel SGX Launch Control hardware bits
  2020-05-15  0:43 ` [PATCH v30 02/20] x86/cpufeatures: x86/msr: Intel SGX Launch Control " Jarkko Sakkinen
@ 2020-05-20 12:23   ` Borislav Petkov
  2020-05-20 14:04     ` Jarkko Sakkinen
  0 siblings, 1 reply; 76+ messages in thread
From: Borislav Petkov @ 2020-05-20 12:23 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	sean.j.christopherson, nhorman, npmccallum, haitao.huang,
	andriy.shevchenko, tglx, kai.svahn, josh, luto, kai.huang,
	rientjes, cedric.xing, puiterwijk, Jethro Beekman


> Subject: Re: [PATCH v30 02/20] x86/cpufeatures: x86/msr: Intel SGX Launch Control hardware bits
							  ^
							Add

Needs a verb.

On Fri, May 15, 2020 at 03:43:52AM +0300, Jarkko Sakkinen wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
> 
> Add X86_FEATURE_SGX_LC, which informs whether or not the CPU supports SGX
> Launch Control.
> 
> Add MSR_IA32_SGXLEPUBKEYHASH{0, 1, 2, 3}, which when combined contain a
> SHA256 hash of a 3072-bit RSA public key. SGX backed software packages, so
> called enclaves, are always signed. All enclaves signed with the public key
> are unconditionally allowed to initialize. [1]
> 
> Add FEATURE_CONTROL_SGX_LE_WR bit of the feature control MSR, which informs
> whether the formentioned MSRs are writable or not. If the bit is off, the

"aforementioned"

> public key MSRs are read-only for the OS.

...

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 01/20] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits
  2020-05-20 12:16   ` Borislav Petkov
@ 2020-05-20 14:00     ` Jarkko Sakkinen
  0 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-20 14:00 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	sean.j.christopherson, nhorman, npmccallum, haitao.huang,
	andriy.shevchenko, tglx, kai.svahn, josh, luto, kai.huang,
	rientjes, cedric.xing, puiterwijk, Jethro Beekman

On Wed, May 20, 2020 at 02:16:21PM +0200, Borislav Petkov wrote:
> On Fri, May 15, 2020 at 03:43:51AM +0300, Jarkko Sakkinen wrote:
> > From: Sean Christopherson <sean.j.christopherson@intel.com>
> > 
> > Add X86_FEATURE_SGX from CPUID.(EAX=7, ECX=1), which informs whether the
> > CPU has SGX.
> > 
> > Add X86_FEATURE_SGX1 and X86_FEATURE_SGX2 from CPUID.(EAX=12H, ECX=0),
> > which describe the level of SGX support available [1].
> > 
> > Remap CPUID.(EAX=12H, ECX=0) bits to the Linux fake CPUID 8 in order to
> > conserve some space. Keep the bit positions intact because KVM requires
> > this. Reserve bits 0-7 for SGX in order to maintain this invariant also
> > when new SGX specific feature bits get added.
> 
> That paragraph needs dropping now.

I dropped it (in my tree).

> -- 
> Regards/Gruss,
>     Boris.
> 
> https://people.kernel.org/tglx/notes-about-netiquette

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 02/20] x86/cpufeatures: x86/msr: Intel SGX Launch Control hardware bits
  2020-05-20 12:23   ` Borislav Petkov
@ 2020-05-20 14:04     ` Jarkko Sakkinen
  0 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-20 14:04 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	sean.j.christopherson, nhorman, npmccallum, haitao.huang,
	andriy.shevchenko, tglx, kai.svahn, josh, luto, kai.huang,
	rientjes, cedric.xing, puiterwijk, Jethro Beekman

On Wed, May 20, 2020 at 02:23:47PM +0200, Borislav Petkov wrote:
> 
> > Subject: Re: [PATCH v30 02/20] x86/cpufeatures: x86/msr: Intel SGX Launch Control hardware bits
> 							  ^
> 							Add
> 
> Needs a verb.

"x86/cpufeatures: x86/msr: Add Intel SGX Launch Control hardware bits"

> On Fri, May 15, 2020 at 03:43:52AM +0300, Jarkko Sakkinen wrote:
> > From: Sean Christopherson <sean.j.christopherson@intel.com>
> > 
> > Add X86_FEATURE_SGX_LC, which informs whether or not the CPU supports SGX
> > Launch Control.
> > 
> > Add MSR_IA32_SGXLEPUBKEYHASH{0, 1, 2, 3}, which when combined contain a
> > SHA256 hash of a 3072-bit RSA public key. SGX backed software packages, so
> > called enclaves, are always signed. All enclaves signed with the public key
> > are unconditionally allowed to initialize. [1]
> > 
> > Add FEATURE_CONTROL_SGX_LE_WR bit of the feature control MSR, which informs
> > whether the formentioned MSRs are writable or not. If the bit is off, the
> 
> "aforementioned"
> 
> > public key MSRs are read-only for the OS.

Thanks, fixed.

> Regards/Gruss,
>     Boris.

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 04/20] x86/sgx: Add SGX microarchitectural data structures
  2020-05-15  0:43 ` [PATCH v30 04/20] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
@ 2020-05-20 18:47   ` Borislav Petkov
  2020-05-20 21:04     ` Sean Christopherson
  2020-05-22 15:54     ` Jarkko Sakkinen
  0 siblings, 2 replies; 76+ messages in thread
From: Borislav Petkov @ 2020-05-20 18:47 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	sean.j.christopherson, nhorman, npmccallum, haitao.huang,
	andriy.shevchenko, tglx, kai.svahn, josh, luto, kai.huang,
	rientjes, cedric.xing, puiterwijk, Jethro Beekman

On Fri, May 15, 2020 at 03:43:54AM +0300, Jarkko Sakkinen wrote:
> +/**
> + * struct sgx_sigstruct_header -  defines author of the enclave
> + * @header1:		constant byte string
> + * @vendor:		must be either 0x0000 or 0x8086

Out of pure curiosity: what is that about?

Nothing in the patchset enforces this, so hw does? If so, why?

Are those vendor IDs going to be assigned by someone or what's up?

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 04/20] x86/sgx: Add SGX microarchitectural data structures
  2020-05-20 18:47   ` Borislav Petkov
@ 2020-05-20 21:04     ` Sean Christopherson
  2020-05-22 15:54     ` Jarkko Sakkinen
  1 sibling, 0 replies; 76+ messages in thread
From: Sean Christopherson @ 2020-05-20 21:04 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: Jarkko Sakkinen, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Jethro Beekman

On Wed, May 20, 2020 at 08:47:45PM +0200, Borislav Petkov wrote:
> On Fri, May 15, 2020 at 03:43:54AM +0300, Jarkko Sakkinen wrote:
> > +/**
> > + * struct sgx_sigstruct_header -  defines author of the enclave
> > + * @header1:		constant byte string
> > + * @vendor:		must be either 0x0000 or 0x8086
> 
> Out of pure curiosity: what is that about?
> 
> Nothing in the patchset enforces this, so hw does? If so, why?

Yes, enforced by hardware during EINIT.

> Are those vendor IDs going to be assigned by someone or what's up?

No, the field has no real meaning or value, and there is no (and never was
any) intent to use it to create an OEM registry or anything of that nature.

It's effectively a reserved-0 field that happens to allow 0x8086 because of
legacy behavior within Intel's signing sytem.  Intel signed enclaves
currently populate it with 0x8086, but future enclaves may change the vendor
to 0x0 just to avoid confusion.  In short, software should ignore the field.

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 10/20] x86/sgx: Linux Enclave Driver
  2020-05-15  0:44 ` [PATCH v30 10/20] x86/sgx: Linux Enclave Driver Jarkko Sakkinen
@ 2020-05-21 19:12   ` Sean Christopherson
  2020-05-22 19:26     ` Jarkko Sakkinen
  2020-05-22 19:39     ` Jarkko Sakkinen
  2020-05-22  3:33   ` Sean Christopherson
  1 sibling, 2 replies; 76+ messages in thread
From: Sean Christopherson @ 2020-05-21 19:12 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: linux-kernel, x86, linux-sgx, akpm, dave.hansen, nhorman,
	npmccallum, haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp,
	josh, luto, kai.huang, rientjes, cedric.xing, puiterwijk,
	linux-security-module, Suresh Siddha, Jethro Beekman,
	Haitao Huang, Chunyang Hui, Jordan Hand, Seth Moore

On Fri, May 15, 2020 at 03:44:00AM +0300, Jarkko Sakkinen wrote:
> +long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
> +{
> +	struct sgx_encl *encl = filep->private_data;
> +	int ret, encl_flags;
> +
> +	encl_flags = atomic_fetch_or(SGX_ENCL_IOCTL, &encl->flags);
> +	if (encl_flags & SGX_ENCL_IOCTL)
> +		return -EBUSY;
> +
> +	if (encl_flags & SGX_ENCL_DEAD)
> +		return -EFAULT;

Returning immediately is wrong as it leaves SGX_ENCL_IOCTL set.  This results
in the application seeing -EBUSY on future ioctls() instead of -EFAULT.  Can be
fixed as below.  Do you want me to send a formal patch on linux-sgx?

diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index 77757a74644d..df35a79e915c 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -751,8 +751,10 @@ long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
        if (encl_flags & SGX_ENCL_IOCTL)
                return -EBUSY;

-       if (encl_flags & SGX_ENCL_DEAD)
-               return -EFAULT;
+       if (encl_flags & SGX_ENCL_DEAD) {
+               ret = -EFAULT;
+               goto out;
+       }

        switch (cmd) {
        case SGX_IOC_ENCLAVE_CREATE:
@@ -772,6 +774,7 @@ long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
                break;
        }

+out:
        atomic_andnot(SGX_ENCL_IOCTL, &encl->flags);

        return ret;


> +
> +	switch (cmd) {
> +	case SGX_IOC_ENCLAVE_CREATE:
> +		ret = sgx_ioc_enclave_create(encl, (void __user *)arg);
> +		break;
> +	case SGX_IOC_ENCLAVE_ADD_PAGES:
> +		ret = sgx_ioc_enclave_add_pages(encl, (void __user *)arg);
> +		break;
> +	case SGX_IOC_ENCLAVE_INIT:
> +		ret = sgx_ioc_enclave_init(encl, (void __user *)arg);
> +		break;
> +	default:
> +		ret = -ENOIOCTLCMD;
> +		break;
> +	}
> +
> +	atomic_andnot(SGX_ENCL_IOCTL, &encl->flags);
> +
> +	return ret;
> +}

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 10/20] x86/sgx: Linux Enclave Driver
  2020-05-15  0:44 ` [PATCH v30 10/20] x86/sgx: Linux Enclave Driver Jarkko Sakkinen
  2020-05-21 19:12   ` Sean Christopherson
@ 2020-05-22  3:33   ` Sean Christopherson
  1 sibling, 0 replies; 76+ messages in thread
From: Sean Christopherson @ 2020-05-22  3:33 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: linux-kernel, x86, linux-sgx, akpm, dave.hansen, nhorman,
	npmccallum, haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp,
	josh, luto, kai.huang, rientjes, cedric.xing, puiterwijk,
	linux-security-module, Suresh Siddha, Jethro Beekman,
	Haitao Huang, Chunyang Hui, Jordan Hand, Seth Moore

On Fri, May 15, 2020 at 03:44:00AM +0300, Jarkko Sakkinen wrote:
> +static int sgx_open(struct inode *inode, struct file *file)
> +{
> +	struct sgx_encl *encl;
> +	int ret;
> +
> +	encl = kzalloc(sizeof(*encl), GFP_KERNEL);
> +	if (!encl)
> +		return -ENOMEM;
> +
> +	atomic_set(&encl->flags, 0);
> +	kref_init(&encl->refcount);
> +	INIT_RADIX_TREE(&encl->page_tree, GFP_KERNEL);
> +	mutex_init(&encl->lock);
> +	INIT_LIST_HEAD(&encl->mm_list);
> +	spin_lock_init(&encl->mm_lock);
> +
> +	ret = init_srcu_struct(&encl->srcu);

We're leaking a wee bit of memory here; enough to burn through 14gb in a few
minutes with my newly resurrected EPC cgroup test.  The possibility for
failure should have been a dead giveaway that this allocates memory, but the
"init" name threw me off. :-/

> +	if (ret) {
> +		kfree(encl);
> +		return ret;
> +	}
> +
> +	file->private_data = encl;
> +
> +	return 0;
> +}

...

> +/**
> + * sgx_encl_release - Destroy an enclave instance
> + * @kref:	address of a kref inside &sgx_encl
> + *
> + * Used together with kref_put(). Frees all the resources associated with the
> + * enclave and the instance itself.
> + */
> +void sgx_encl_release(struct kref *ref)
> +{
> +	struct sgx_encl *encl = container_of(ref, struct sgx_encl, refcount);
> +
> +	sgx_encl_destroy(encl);
> +
> +	if (encl->backing)
> +		fput(encl->backing);

The above mem leak can be fixed by adding

	cleanup_srcu_struct(&encl->srcu);
> +
> +	WARN_ON_ONCE(!list_empty(&encl->mm_list));
> +
> +	/* Detect EPC page leak's. */
> +	WARN_ON_ONCE(encl->secs_child_cnt);
> +	WARN_ON_ONCE(encl->secs.epc_page);
> +
> +	kfree(encl);
> +}

...

> +static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long src,
> +			     unsigned long offset, unsigned long length,
> +			     struct sgx_secinfo *secinfo, unsigned long flags)
> +{

...

> +err_out:
> +	radix_tree_delete(&encl_page->encl->page_tree,
> +			  PFN_DOWN(encl_page->desc));
> +
> +err_out_unlock:
> +	mutex_unlock(&encl->lock);
> +	up_read(&current->mm->mmap_sem);
> +
> +err_out_free:
> +	sgx_free_page(epc_page);
> +	kfree(encl_page);
> +
> +	/*
> +	 * Destroy enclave on ENCLS failure as this means that EPC has been
> +	 * invalidated.
> +	 */
> +	if (ret == -EIO)
> +		sgx_encl_destroy(encl);

This needs to be called with encl->lock held to prevent racing with the
reclaimer, e.g. sgx_encl_destroy() and sgx_reclaimer_write() can combine to
corrupt secs_child_cnt, among other badness.

It's probably worth adding a lockdep assert in sgx_encl_destroy() as well.

We can either keep the lock across the above frees or retake the lock.  I
like retaking the lock to avoid inverting the ordering between encl->lock
and mmap_sem (even though it's benign).  This is an extremely rare path,
no need to shave cycles.

> +
> +	return ret;
> +}

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 12/20] x86/sgx: Add a page reclaimer
  2020-05-15  0:44 ` [PATCH v30 12/20] x86/sgx: Add a page reclaimer Jarkko Sakkinen
@ 2020-05-22  6:58   ` Sean Christopherson
  2020-05-22 19:57     ` Jarkko Sakkinen
  2020-05-22  7:15   ` Sean Christopherson
  1 sibling, 1 reply; 76+ messages in thread
From: Sean Christopherson @ 2020-05-22  6:58 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: linux-kernel, x86, linux-sgx, akpm, dave.hansen, nhorman,
	npmccallum, haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp,
	josh, luto, kai.huang, rientjes, cedric.xing, puiterwijk,
	linux-mm, Jethro Beekman, Jordan Hand, Chunyang Hui, Seth Moore

On Fri, May 15, 2020 at 03:44:02AM +0300, Jarkko Sakkinen wrote:
> +/**
> + * sgx_reclaim_pages() - Reclaim EPC pages from the consumers
> + *
> + * Take a fixed number of pages from the head of the active page pool and
> + * reclaim them to the enclave's private shmem files. Skip the pages, which
> + * have been accessed since the last scan. Move those pages to the tail of
> + * active page pool so that the pages get scanned in LRU like fashion.
> + */
> +void sgx_reclaim_pages(void)
> +{
> +	struct sgx_epc_page *chunk[SGX_NR_TO_SCAN];
> +	struct sgx_backing backing[SGX_NR_TO_SCAN];
> +	struct sgx_epc_section *section;
> +	struct sgx_encl_page *encl_page;
> +	struct sgx_epc_page *epc_page;
> +	int cnt = 0;
> +	int ret;
> +	int i;
> +
> +	spin_lock(&sgx_active_page_list_lock);
> +	for (i = 0; i < SGX_NR_TO_SCAN; i++) {
> +		if (list_empty(&sgx_active_page_list))
> +			break;
> +
> +		epc_page = list_first_entry(&sgx_active_page_list,
> +					    struct sgx_epc_page, list);
> +		list_del_init(&epc_page->list);
> +		encl_page = epc_page->owner;
> +
> +		if (kref_get_unless_zero(&encl_page->encl->refcount) != 0)
> +			chunk[cnt++] = epc_page;
> +		else
> +			/* The owner is freeing the page. No need to add the
> +			 * page back to the list of reclaimable pages.
> +			 */
> +			epc_page->desc &= ~SGX_EPC_PAGE_RECLAIMABLE;
> +	}
> +	spin_unlock(&sgx_active_page_list_lock);
> +
> +	for (i = 0; i < cnt; i++) {
> +		epc_page = chunk[i];
> +		encl_page = epc_page->owner;
> +
> +		if (!sgx_reclaimer_age(epc_page))
> +			goto skip;
> +
> +		ret = sgx_encl_get_backing(encl_page->encl,
> +					   SGX_ENCL_PAGE_INDEX(encl_page),
> +					   &backing[i]);
> +		if (ret)
> +			goto skip;
> +
> +		mutex_lock(&encl_page->encl->lock);
> +		encl_page->desc |= SGX_ENCL_PAGE_RECLAIMED;
> +		mutex_unlock(&encl_page->encl->lock);
> +		continue;
> +
> +skip:
> +		kref_put(&encl_page->encl->refcount, sgx_encl_release);
> +
> +		spin_lock(&sgx_active_page_list_lock);
> +		list_add_tail(&epc_page->list, &sgx_active_page_list);
> +		spin_unlock(&sgx_active_page_list_lock);

Ugh, this is wrong.  If the above kref_put() drops the last reference and
releases the enclave, adding the page to the active page list will result
in a use-after-free as the enclave will have been freed.  It also leaks the
EPC page because sgx_encl_destroy() skips pages that are in the process of
being reclaimed (as detected by list_empty()).

The "original" code did the put() after list_add_tail(), but was moved in
v15 to fix a bug where the put() could drop a reference to the wrong enclave
if the page was freed and reallocated by a different CPU between
list_add_tail() and put().  But, that particular bug only occurred because
the code at the time was:

	sgx_encl_page_put(epc_page);

I.e. the backpointer in epc_page was consumed after dropping the spin lock.
So long as epc_page->owner (well, epc_page in general) isn't dereferenced,
I'm 99% certain this can be fixed simply by doing kref_put() after moving
the page back to the active page list.

> +
> +		chunk[i] = NULL;
> +	}
> +
> +	for (i = 0; i < cnt; i++) {
> +		epc_page = chunk[i];
> +		if (epc_page)
> +			sgx_reclaimer_block(epc_page);
> +	}
> +
> +	for (i = 0; i < cnt; i++) {
> +		epc_page = chunk[i];
> +		if (!epc_page)
> +			continue;
> +
> +		encl_page = epc_page->owner;
> +		sgx_reclaimer_write(epc_page, &backing[i]);
> +		sgx_encl_put_backing(&backing[i], true);
> +
> +		kref_put(&encl_page->encl->refcount, sgx_encl_release);
> +		epc_page->desc &= ~SGX_EPC_PAGE_RECLAIMABLE;
> +
> +		section = sgx_epc_section(epc_page);
> +		spin_lock(&section->lock);
> +		list_add_tail(&epc_page->list, &section->page_list);
> +		section->free_cnt++;
> +		spin_unlock(&section->lock);
> +	}
> +}

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 12/20] x86/sgx: Add a page reclaimer
  2020-05-15  0:44 ` [PATCH v30 12/20] x86/sgx: Add a page reclaimer Jarkko Sakkinen
  2020-05-22  6:58   ` Sean Christopherson
@ 2020-05-22  7:15   ` Sean Christopherson
  2020-05-22 19:47     ` Jarkko Sakkinen
  1 sibling, 1 reply; 76+ messages in thread
From: Sean Christopherson @ 2020-05-22  7:15 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: linux-kernel, x86, linux-sgx, akpm, dave.hansen, nhorman,
	npmccallum, haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp,
	josh, luto, kai.huang, rientjes, cedric.xing, puiterwijk,
	linux-mm, Jethro Beekman, Jordan Hand, Chunyang Hui, Seth Moore

On Fri, May 15, 2020 at 03:44:02AM +0300, Jarkko Sakkinen wrote:
> +static void sgx_reclaimer_write(struct sgx_epc_page *epc_page,
> +				struct sgx_backing *backing)
> +{
> +	struct sgx_encl_page *encl_page = epc_page->owner;
> +	struct sgx_encl *encl = encl_page->encl;
> +	struct sgx_backing secs_backing;
> +	int ret;
> +
> +	mutex_lock(&encl->lock);
> +
> +	if (atomic_read(&encl->flags) & SGX_ENCL_DEAD) {
> +		ret = __eremove(sgx_epc_addr(epc_page));
> +		ENCLS_WARN(ret, "EREMOVE returned %d\n");

The " returned %d\n" is unnecessary and leads to a bad message, ENCLS_WARN
handles the message and formatting, i.e. this should simply be:

		ENCLS_WARN(ret, "EREMOVE");

> +	} else {
> +		sgx_encl_ewb(epc_page, backing);
> +	}
> +
> +	encl_page->epc_page = NULL;
> +	encl->secs_child_cnt--;

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 04/20] x86/sgx: Add SGX microarchitectural data structures
  2020-05-20 18:47   ` Borislav Petkov
  2020-05-20 21:04     ` Sean Christopherson
@ 2020-05-22 15:54     ` Jarkko Sakkinen
  2020-05-22 16:13       ` Sean Christopherson
  1 sibling, 1 reply; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-22 15:54 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	sean.j.christopherson, nhorman, npmccallum, haitao.huang,
	andriy.shevchenko, tglx, kai.svahn, josh, luto, kai.huang,
	rientjes, cedric.xing, puiterwijk, Jethro Beekman

On Wed, May 20, 2020 at 08:47:45PM +0200, Borislav Petkov wrote:
> On Fri, May 15, 2020 at 03:43:54AM +0300, Jarkko Sakkinen wrote:
> > +/**
> > + * struct sgx_sigstruct_header -  defines author of the enclave
> > + * @header1:		constant byte string
> > + * @vendor:		must be either 0x0000 or 0x8086
> 
> Out of pure curiosity: what is that about?
> 
> Nothing in the patchset enforces this, so hw does? If so, why?
> 
> Are those vendor IDs going to be assigned by someone or what's up?
> 
> Thx.

In SGX1 world 0x8086 was used to mark architectural enclaves and 0x0000
user run enclaves. In SGX2 world they are irrelevant. In order to retain
compatiblity I'd add an explicit check to:

1. Allow vendor ID of 0x0000 or 0x8086.
2. Reject other vendor ID's (-EINVAL).

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 04/20] x86/sgx: Add SGX microarchitectural data structures
  2020-05-22 15:54     ` Jarkko Sakkinen
@ 2020-05-22 16:13       ` Sean Christopherson
  2020-05-22 19:50         ` Jarkko Sakkinen
  0 siblings, 1 reply; 76+ messages in thread
From: Sean Christopherson @ 2020-05-22 16:13 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: Borislav Petkov, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Jethro Beekman

On Fri, May 22, 2020 at 06:54:05PM +0300, Jarkko Sakkinen wrote:
> On Wed, May 20, 2020 at 08:47:45PM +0200, Borislav Petkov wrote:
> > On Fri, May 15, 2020 at 03:43:54AM +0300, Jarkko Sakkinen wrote:
> > > +/**
> > > + * struct sgx_sigstruct_header -  defines author of the enclave
> > > + * @header1:		constant byte string
> > > + * @vendor:		must be either 0x0000 or 0x8086
> > 
> > Out of pure curiosity: what is that about?
> > 
> > Nothing in the patchset enforces this, so hw does? If so, why?
> > 
> > Are those vendor IDs going to be assigned by someone or what's up?
> > 
> > Thx.
> 
> In SGX1 world 0x8086 was used to mark architectural enclaves and 0x0000
> user run enclaves. In SGX2 world they are irrelevant.

That's not accurate, the vendor is irrelevant in all SGX eras, e.g. enclaves
signed by someone other than Intel can use 0x8086 on SGX1 hardware and even
pre-LC hardware.  0x8086 is/was used as an _informal_ "this is an
Intel-signed enclave", but in no way was it mandatory or reliable.

> In order to retain compatiblity I'd add an explicit check to:
> 
> 1. Allow vendor ID of 0x0000 or 0x8086.
> 2. Reject other vendor ID's (-EINVAL).

Unless we also check the reserved fields in sigstruct, I don't see the
point.  Even then, I don't understand what the kernel gains from enforcing
anything with respect to sigstruct.  Enforcing the SECS makes sense as we
don't want to allow userspace to enable some unknown future feature.  But
sigstruct is purely for verification, we (Intel) have far bigger problems
if Intel is enabling new behavior via sigstruct.

That being said, I'm not dead set against sanity checking sigstruct, I just
think it'd be a waste of cycles.

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 10/20] x86/sgx: Linux Enclave Driver
  2020-05-21 19:12   ` Sean Christopherson
@ 2020-05-22 19:26     ` Jarkko Sakkinen
  2020-05-22 19:39     ` Jarkko Sakkinen
  1 sibling, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-22 19:26 UTC (permalink / raw)
  To: Sean Christopherson
  Cc: linux-kernel, x86, linux-sgx, akpm, dave.hansen, nhorman,
	npmccallum, haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp,
	josh, luto, kai.huang, rientjes, cedric.xing, puiterwijk,
	linux-security-module, Suresh Siddha, Jethro Beekman,
	Haitao Huang, Chunyang Hui, Jordan Hand, Seth Moore

On Thu, May 21, 2020 at 12:12:36PM -0700, Sean Christopherson wrote:
> On Fri, May 15, 2020 at 03:44:00AM +0300, Jarkko Sakkinen wrote:
> > +long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
> > +{
> > +	struct sgx_encl *encl = filep->private_data;
> > +	int ret, encl_flags;
> > +
> > +	encl_flags = atomic_fetch_or(SGX_ENCL_IOCTL, &encl->flags);
> > +	if (encl_flags & SGX_ENCL_IOCTL)
> > +		return -EBUSY;
> > +
> > +	if (encl_flags & SGX_ENCL_DEAD)
> > +		return -EFAULT;
> 
> Returning immediately is wrong as it leaves SGX_ENCL_IOCTL set.  This results
> in the application seeing -EBUSY on future ioctls() instead of -EFAULT.  Can be
> fixed as below.  Do you want me to send a formal patch on linux-sgx?

I just rewrote the same thing.

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 10/20] x86/sgx: Linux Enclave Driver
  2020-05-21 19:12   ` Sean Christopherson
  2020-05-22 19:26     ` Jarkko Sakkinen
@ 2020-05-22 19:39     ` Jarkko Sakkinen
  1 sibling, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-22 19:39 UTC (permalink / raw)
  To: Sean Christopherson
  Cc: linux-kernel, x86, linux-sgx, akpm, dave.hansen, nhorman,
	npmccallum, haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp,
	josh, luto, kai.huang, rientjes, cedric.xing, puiterwijk,
	linux-security-module, Suresh Siddha, Jethro Beekman,
	Haitao Huang, Chunyang Hui, Jordan Hand, Seth Moore

On Thu, May 21, 2020 at 12:12:36PM -0700, Sean Christopherson wrote:
> On Fri, May 15, 2020 at 03:44:00AM +0300, Jarkko Sakkinen wrote:
> > +long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
> > +{
> > +	struct sgx_encl *encl = filep->private_data;
> > +	int ret, encl_flags;
> > +
> > +	encl_flags = atomic_fetch_or(SGX_ENCL_IOCTL, &encl->flags);
> > +	if (encl_flags & SGX_ENCL_IOCTL)
> > +		return -EBUSY;
> > +
> > +	if (encl_flags & SGX_ENCL_DEAD)
> > +		return -EFAULT;
> 
> Returning immediately is wrong as it leaves SGX_ENCL_IOCTL set.  This results
> in the application seeing -EBUSY on future ioctls() instead of -EFAULT.  Can be
> fixed as below.  Do you want me to send a formal patch on linux-sgx?
> 
> diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
> index 77757a74644d..df35a79e915c 100644
> --- a/arch/x86/kernel/cpu/sgx/ioctl.c
> +++ b/arch/x86/kernel/cpu/sgx/ioctl.c
> @@ -751,8 +751,10 @@ long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
>         if (encl_flags & SGX_ENCL_IOCTL)
>                 return -EBUSY;
> 
> -       if (encl_flags & SGX_ENCL_DEAD)
> -               return -EFAULT;
> +       if (encl_flags & SGX_ENCL_DEAD) {
> +               ret = -EFAULT;
> +               goto out;
> +       }
> 
>         switch (cmd) {
>         case SGX_IOC_ENCLAVE_CREATE:
> @@ -772,6 +774,7 @@ long sgx_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
>                 break;
>         }
> 
> +out:
>         atomic_andnot(SGX_ENCL_IOCTL, &encl->flags);
> 
>         return ret;
> 
> 
> > +
> > +	switch (cmd) {
> > +	case SGX_IOC_ENCLAVE_CREATE:
> > +		ret = sgx_ioc_enclave_create(encl, (void __user *)arg);
> > +		break;
> > +	case SGX_IOC_ENCLAVE_ADD_PAGES:
> > +		ret = sgx_ioc_enclave_add_pages(encl, (void __user *)arg);
> > +		break;
> > +	case SGX_IOC_ENCLAVE_INIT:
> > +		ret = sgx_ioc_enclave_init(encl, (void __user *)arg);
> > +		break;
> > +	default:
> > +		ret = -ENOIOCTLCMD;
> > +		break;
> > +	}
> > +
> > +	atomic_andnot(SGX_ENCL_IOCTL, &encl->flags);
> > +
> > +	return ret;
> > +}

Thanks. Fixed in my tree:

v31:
* Unset SGX_ENCL_IOCTL in the error path of checking encl->flags in order
  to prevent leaving it set, and thus block any further ioctl calls.
* Added missing cleanup_srcu_struct() call to sgx_encl_release().
* Take encl->lock in sgx_encl_add_page() in order to prevent races with
  the page reclaimer.

 /Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 12/20] x86/sgx: Add a page reclaimer
  2020-05-22  7:15   ` Sean Christopherson
@ 2020-05-22 19:47     ` Jarkko Sakkinen
  0 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-22 19:47 UTC (permalink / raw)
  To: Sean Christopherson
  Cc: linux-kernel, x86, linux-sgx, akpm, dave.hansen, nhorman,
	npmccallum, haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp,
	josh, luto, kai.huang, rientjes, cedric.xing, puiterwijk,
	linux-mm, Jethro Beekman, Jordan Hand, Chunyang Hui, Seth Moore

On Fri, May 22, 2020 at 12:15:53AM -0700, Sean Christopherson wrote:
> On Fri, May 15, 2020 at 03:44:02AM +0300, Jarkko Sakkinen wrote:
> > +static void sgx_reclaimer_write(struct sgx_epc_page *epc_page,
> > +				struct sgx_backing *backing)
> > +{
> > +	struct sgx_encl_page *encl_page = epc_page->owner;
> > +	struct sgx_encl *encl = encl_page->encl;
> > +	struct sgx_backing secs_backing;
> > +	int ret;
> > +
> > +	mutex_lock(&encl->lock);
> > +
> > +	if (atomic_read(&encl->flags) & SGX_ENCL_DEAD) {
> > +		ret = __eremove(sgx_epc_addr(epc_page));
> > +		ENCLS_WARN(ret, "EREMOVE returned %d\n");
> 
> The " returned %d\n" is unnecessary and leads to a bad message, ENCLS_WARN
> handles the message and formatting, i.e. this should simply be:
> 
> 		ENCLS_WARN(ret, "EREMOVE");

Sure. Did not make a changelog entry of this (because it is a cosmetic
fix), but it is fixed in my tree.

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 04/20] x86/sgx: Add SGX microarchitectural data structures
  2020-05-22 16:13       ` Sean Christopherson
@ 2020-05-22 19:50         ` Jarkko Sakkinen
  2020-05-25  8:20           ` Borislav Petkov
  0 siblings, 1 reply; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-22 19:50 UTC (permalink / raw)
  To: Sean Christopherson
  Cc: Borislav Petkov, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Jethro Beekman

On Fri, May 22, 2020 at 09:13:26AM -0700, Sean Christopherson wrote:
> On Fri, May 22, 2020 at 06:54:05PM +0300, Jarkko Sakkinen wrote:
> > On Wed, May 20, 2020 at 08:47:45PM +0200, Borislav Petkov wrote:
> > > On Fri, May 15, 2020 at 03:43:54AM +0300, Jarkko Sakkinen wrote:
> > > > +/**
> > > > + * struct sgx_sigstruct_header -  defines author of the enclave
> > > > + * @header1:		constant byte string
> > > > + * @vendor:		must be either 0x0000 or 0x8086
> > > 
> > > Out of pure curiosity: what is that about?
> > > 
> > > Nothing in the patchset enforces this, so hw does? If so, why?
> > > 
> > > Are those vendor IDs going to be assigned by someone or what's up?
> > > 
> > > Thx.
> > 
> > In SGX1 world 0x8086 was used to mark architectural enclaves and 0x0000
> > user run enclaves. In SGX2 world they are irrelevant.
> 
> That's not accurate, the vendor is irrelevant in all SGX eras, e.g. enclaves
> signed by someone other than Intel can use 0x8086 on SGX1 hardware and even
> pre-LC hardware.  0x8086 is/was used as an _informal_ "this is an
> Intel-signed enclave", but in no way was it mandatory or reliable.
> 
> > In order to retain compatiblity I'd add an explicit check to:
> > 
> > 1. Allow vendor ID of 0x0000 or 0x8086.
> > 2. Reject other vendor ID's (-EINVAL).
> 
> Unless we also check the reserved fields in sigstruct, I don't see the
> point.  Even then, I don't understand what the kernel gains from enforcing
> anything with respect to sigstruct.  Enforcing the SECS makes sense as we
> don't want to allow userspace to enable some unknown future feature.  But
> sigstruct is purely for verification, we (Intel) have far bigger problems
> if Intel is enabling new behavior via sigstruct.
> 
> That being said, I'm not dead set against sanity checking sigstruct, I just
> think it'd be a waste of cycles.

If other values except two are never going to be used it is more than a
legit point to validate this field.

It also the potential to use ~0x8086 bits to be defined later if ever
needed lets say for some kernel specific purpose.

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 12/20] x86/sgx: Add a page reclaimer
  2020-05-22  6:58   ` Sean Christopherson
@ 2020-05-22 19:57     ` Jarkko Sakkinen
  2020-05-22 21:52       ` Sean Christopherson
  0 siblings, 1 reply; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-22 19:57 UTC (permalink / raw)
  To: Sean Christopherson
  Cc: linux-kernel, x86, linux-sgx, akpm, dave.hansen, nhorman,
	npmccallum, haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp,
	josh, luto, kai.huang, rientjes, cedric.xing, puiterwijk,
	linux-mm, Jethro Beekman, Jordan Hand, Chunyang Hui, Seth Moore

On Thu, May 21, 2020 at 11:58:02PM -0700, Sean Christopherson wrote:
> > +		kref_put(&encl_page->encl->refcount, sgx_encl_release);
> > +
> > +		spin_lock(&sgx_active_page_list_lock);
> > +		list_add_tail(&epc_page->list, &sgx_active_page_list);
> > +		spin_unlock(&sgx_active_page_list_lock);
> 
> Ugh, this is wrong.  If the above kref_put() drops the last reference and
> releases the enclave, adding the page to the active page list will result
> in a use-after-free as the enclave will have been freed.  It also leaks the
> EPC page because sgx_encl_destroy() skips pages that are in the process of
> being reclaimed (as detected by list_empty()).
> 
> The "original" code did the put() after list_add_tail(), but was moved in
> v15 to fix a bug where the put() could drop a reference to the wrong enclave
> if the page was freed and reallocated by a different CPU between
> list_add_tail() and put().  But, that particular bug only occurred because
> the code at the time was:
> 
> 	sgx_encl_page_put(epc_page);
> 
> I.e. the backpointer in epc_page was consumed after dropping the spin lock.
> So long as epc_page->owner (well, epc_page in general) isn't dereferenced,
> I'm 99% certain this can be fixed simply by doing kref_put() after moving
> the page back to the active page list.

Yes. It is certainly a regression to not call it after
sgx_active_page_list. That was a good catch, thanks.

v31:
* Unset SGX_ENCL_IOCTL in the error path of checking encl->flags in order
  to prevent leaving it set and thus block any further ioctl calls.
* Added missing cleanup_srcu_struct() call to sgx_encl_release().
* Take encl->lock in sgx_encl_add_page() in order to prevent races with
  the page reclaimer.
* Fix a use-after-free bug from page reclaimer. Call kref_put() for the
  encl->refcount only after putting enclave page back to the active page
  list because it could be the last ref to the enclave.

I'm ready to send a new version of the patch set once there is a
conclusion with the sigstruct vendor field.

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 12/20] x86/sgx: Add a page reclaimer
  2020-05-22 19:57     ` Jarkko Sakkinen
@ 2020-05-22 21:52       ` Sean Christopherson
  0 siblings, 0 replies; 76+ messages in thread
From: Sean Christopherson @ 2020-05-22 21:52 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: linux-kernel, x86, linux-sgx, akpm, dave.hansen, nhorman,
	npmccallum, haitao.huang, andriy.shevchenko, tglx, kai.svahn, bp,
	josh, luto, kai.huang, rientjes, cedric.xing, puiterwijk,
	linux-mm, Jethro Beekman, Jordan Hand, Chunyang Hui, Seth Moore

On Fri, May 22, 2020 at 10:57:05PM +0300, Jarkko Sakkinen wrote:
> v31:
> * Unset SGX_ENCL_IOCTL in the error path of checking encl->flags in order
>   to prevent leaving it set and thus block any further ioctl calls.
> * Added missing cleanup_srcu_struct() call to sgx_encl_release().
> * Take encl->lock in sgx_encl_add_page() in order to prevent races with
>   the page reclaimer.
> * Fix a use-after-free bug from page reclaimer. Call kref_put() for the
>   encl->refcount only after putting enclave page back to the active page
>   list because it could be the last ref to the enclave.
> 
> I'm ready to send a new version of the patch set once there is a
> conclusion with the sigstruct vendor field.

Fire away, nothing pending on my end, the cgroup tests appear to be running
clean.

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 04/20] x86/sgx: Add SGX microarchitectural data structures
  2020-05-22 19:50         ` Jarkko Sakkinen
@ 2020-05-25  8:20           ` Borislav Petkov
  2020-05-27 19:43             ` Jarkko Sakkinen
  0 siblings, 1 reply; 76+ messages in thread
From: Borislav Petkov @ 2020-05-25  8:20 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: Sean Christopherson, linux-kernel, x86, linux-sgx, akpm,
	dave.hansen, nhorman, npmccallum, haitao.huang,
	andriy.shevchenko, tglx, kai.svahn, josh, luto, kai.huang,
	rientjes, cedric.xing, puiterwijk, Jethro Beekman

On Fri, May 22, 2020 at 10:50:17PM +0300, Jarkko Sakkinen wrote:
> If other values except two are never going to be used it is more than a
> legit point to validate this field.
> 
> It also the potential to use ~0x8086 bits to be defined later if ever
> needed lets say for some kernel specific purpose.

Yah, let's cover our ass for the future. We have all seen the "this
won't be used" but then "we're using it" change of heart. IOW, let's
align with what the hw checks and we can always relax that in the future
but not the other way around.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 07/20] x86/sgx: Enumerate and track EPC sections
  2020-05-15  0:43 ` [PATCH v30 07/20] x86/sgx: Enumerate and track EPC sections Jarkko Sakkinen
@ 2020-05-25  9:23   ` Borislav Petkov
  2020-05-27  3:56     ` Sean Christopherson
  2020-05-28  5:13     ` Jarkko Sakkinen
  0 siblings, 2 replies; 76+ messages in thread
From: Borislav Petkov @ 2020-05-25  9:23 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	sean.j.christopherson, nhorman, npmccallum, haitao.huang,
	andriy.shevchenko, tglx, kai.svahn, josh, luto, kai.huang,
	rientjes, cedric.xing, puiterwijk, Serge Ayoun, Jethro Beekman

On Fri, May 15, 2020 at 03:43:57AM +0300, Jarkko Sakkinen wrote:
> +config INTEL_SGX
> +	bool "Intel SGX"
> +	depends on X86_64 && CPU_SUP_INTEL
> +	select SRCU
> +	select MMU_NOTIFIER
> +	help
> +	  Intel(R) SGX is a set of CPU instructions that can be used by
> +	  applications to set aside private regions of code and data, referred
> +	  to as enclaves. An enclave's private memory can only be accessed by
> +	  code running within the enclave. Accesses from outside the enclave,
> +	  including other enclaves, are disallowed by hardware.
> +
> +	  If unsure, say N.
> +

Enabling this gives:

In file included from arch/x86/kernel/cpu/sgx/main.c:11:
arch/x86/kernel/cpu/sgx/encls.h:189:51: warning: ‘struct sgx_einittoken’ declared inside parameter list will not be visible outside of this definition or declaration
  189 | static inline int __einit(void *sigstruct, struct sgx_einittoken *einittoken,
      |                                                   ^~~~~~~~~~~~~~
In file included from arch/x86/kernel/cpu/sgx/reclaim.c:12:
arch/x86/kernel/cpu/sgx/encls.h:189:51: warning: ‘struct sgx_einittoken’ declared inside parameter list will not be visible outside of this definition or declaration
  189 | static inline int __einit(void *sigstruct, struct sgx_einittoken *einittoken,
      |

You need a forward declaration somewhere.

>  config EFI
>  	bool "EFI runtime service support"
>  	depends on ACPI
> diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
> index 7dc4ad68eb41..45534fb81007 100644
> --- a/arch/x86/kernel/cpu/Makefile
> +++ b/arch/x86/kernel/cpu/Makefile
> @@ -46,6 +46,7 @@ obj-$(CONFIG_X86_MCE)			+= mce/
>  obj-$(CONFIG_MTRR)			+= mtrr/
>  obj-$(CONFIG_MICROCODE)			+= microcode/
>  obj-$(CONFIG_X86_CPU_RESCTRL)		+= resctrl/
> +obj-$(CONFIG_INTEL_SGX)			+= sgx/
>  
>  obj-$(CONFIG_X86_LOCAL_APIC)		+= perfctr-watchdog.o
>  
> diff --git a/arch/x86/kernel/cpu/sgx/Makefile b/arch/x86/kernel/cpu/sgx/Makefile
> new file mode 100644
> index 000000000000..2dec75916a5e
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/Makefile
> @@ -0,0 +1,3 @@
> +obj-y += \
> +	main.o \
> +	reclaim.o
> diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
> new file mode 100644
> index 000000000000..38424c1e8341
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/main.c
> @@ -0,0 +1,151 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
> +// Copyright(c) 2016-17 Intel Corporation.
> +
> +#include <linux/freezer.h>
> +#include <linux/highmem.h>
> +#include <linux/kthread.h>
> +#include <linux/pagemap.h>
> +#include <linux/ratelimit.h>
> +#include <linux/sched/signal.h>
> +#include <linux/slab.h>
> +#include "encls.h"
> +
> +struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
> +int sgx_nr_epc_sections;

We have become very averse against global stuff. What is going to use
those, only sgx code I assume...?

> +static bool __init sgx_page_cache_init(void)
> +{
> +	u32 eax, ebx, ecx, edx, type;
> +	u64 pa, size;
> +	int i;
> +
> +	for (i = 0; i <= ARRAY_SIZE(sgx_epc_sections); i++) {
> +		cpuid_count(SGX_CPUID, i + SGX_CPUID_FIRST_VARIABLE_SUB_LEAF,
> +			    &eax, &ebx, &ecx, &edx);
> +
> +		type = eax & SGX_CPUID_SUB_LEAF_TYPE_MASK;
> +		if (type == SGX_CPUID_SUB_LEAF_INVALID)
> +			break;
> +
> +		if (type != SGX_CPUID_SUB_LEAF_EPC_SECTION) {
> +			pr_err_once("Unknown EPC section type: %u\n", type);
> +			break;
> +		}
> +
> +		if (i == ARRAY_SIZE(sgx_epc_sections)) {
> +			pr_warn("No free slot for an EPC section\n");
> +			break;
> +		}

This is also the loop termination: do we really need this warn or can
the loop simply do "i < ARRAY_SIZE" ?

If the warn is needed, it can be after the loop too.

> +
> +		pa = sgx_calc_section_metric(eax, ebx);
> +		size = sgx_calc_section_metric(ecx, edx);
> +
> +		pr_info("EPC section 0x%llx-0x%llx\n", pa, pa + size - 1);

I'm assuming that's useful information to issue in dmesg?

> diff --git a/arch/x86/kernel/cpu/sgx/reclaim.c b/arch/x86/kernel/cpu/sgx/reclaim.c
> new file mode 100644
> index 000000000000..215371588a25
> --- /dev/null
> +++ b/arch/x86/kernel/cpu/sgx/reclaim.c
> @@ -0,0 +1,82 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
> +// Copyright(c) 2016-19 Intel Corporation.
> +
> +#include <linux/freezer.h>
> +#include <linux/highmem.h>
> +#include <linux/kthread.h>
> +#include <linux/pagemap.h>
> +#include <linux/ratelimit.h>
> +#include <linux/slab.h>
> +#include <linux/sched/mm.h>
> +#include <linux/sched/signal.h>
> +#include "encls.h"
> +
> +struct task_struct *ksgxswapd_tsk;

Same for this one: also shared only among sgx code?

> +/**
> + * enum sgx_epc_page_desc - bits and masks for an EPC page's descriptor
> + * %SGX_EPC_SECTION_MASK:	SGX allows to have multiple EPC sections in the
> + *				physical memory. The existing and near-future
> + *				hardware defines at most eight sections, hence
> + *				three bits to hold a section.
> + */
> +enum sgx_epc_page_desc {
> +	SGX_EPC_SECTION_MASK			= GENMASK_ULL(3, 0),

If that should be three bits, then it should be (2, 0). Because now you
have 4 bits:

# arch/x86/kernel/cpu/sgx/sgx.h:56:     return &sgx_epc_sections[page->desc & SGX_EPC_SECTION_MASK];
        andl    $15, %edx       #, _22
		^^^

> +	/* bits 12-63 are reserved for the physical page address of the page */
> +};
> +
> +#define SGX_MAX_EPC_SECTIONS (SGX_EPC_SECTION_MASK + 1)
> +
> +extern struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
> +
> +static inline struct sgx_epc_section *sgx_epc_section(struct sgx_epc_page *page)

This function name needs a verb. "get" sounds fitting. :)

> +{
> +	return &sgx_epc_sections[page->desc & SGX_EPC_SECTION_MASK];
> +}
> +
> +static inline void *sgx_epc_addr(struct sgx_epc_page *page)

Ditto.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
  2020-05-15  0:43 ` [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages Jarkko Sakkinen
@ 2020-05-26 12:52   ` Borislav Petkov
  2020-05-27  4:21     ` Sean Christopherson
  0 siblings, 1 reply; 76+ messages in thread
From: Borislav Petkov @ 2020-05-26 12:52 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	sean.j.christopherson, nhorman, npmccallum, haitao.huang,
	andriy.shevchenko, tglx, kai.svahn, josh, luto, kai.huang,
	rientjes, cedric.xing, puiterwijk, Jethro Beekman

On Fri, May 15, 2020 at 03:43:58AM +0300, Jarkko Sakkinen wrote:
> Add functions for allocating page from Enclave Page Cache (EPC). A page is

				pages

> allocated by going through the EPC sections and returning the first free
> page.
> 
> When a page is freed, it might have a valid state, which means that the
> callee has assigned it to an enclave, which are protected memory ares used

								  areas

although explaining what enclaves are has already happened so probably
not needed here too.

> to run code protected from outside access. The page is returned back to the
> invalid state with ENCLS[EREMOVE] [1].
> 
> [1] Intel SDM: 40.3 INTEL® SGX SYSTEM LEAF FUNCTION REFERENCE
> 
> Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Acked-by: Jethro Beekman <jethro@fortanix.com>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> ---
>  arch/x86/kernel/cpu/sgx/main.c | 60 ++++++++++++++++++++++++++++++++++
>  arch/x86/kernel/cpu/sgx/sgx.h  |  3 ++
>  2 files changed, 63 insertions(+)
> 
> diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
> index 38424c1e8341..60d82e7537c8 100644
> --- a/arch/x86/kernel/cpu/sgx/main.c
> +++ b/arch/x86/kernel/cpu/sgx/main.c
> @@ -13,6 +13,66 @@
>  struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
>  int sgx_nr_epc_sections;
>  
> +static struct sgx_epc_page *__sgx_try_alloc_page(struct sgx_epc_section *section)
> +{
> +	struct sgx_epc_page *page;
> +
> +	if (list_empty(&section->page_list))
> +		return NULL;
> +
> +	page = list_first_entry(&section->page_list, struct sgx_epc_page, list);
> +	list_del_init(&page->list);
> +	return page;
> +}
> +
> +/**
> + * sgx_try_alloc_page() - Allocate an EPC page

Uuh, this is confusing. Looking forward into the patchset, you guys have

sgx_alloc_page()
sgx_alloc_va_page()

and this here

sgx_try_alloc_page()

So this one here should be called sgx_alloc_epc_page() if we're going to
differentiate *what* it is allocating.

But then looking at sgx_alloc_page():

+ * sgx_alloc_page() - Allocate an EPC page
...

+ struct sgx_epc_page *sgx_alloc_page(void *owner, bool reclaim)

this one returns a struct sgx_epc_page * too.

The former "allocates" from the EPC cache so I'm thinking former should
not have "alloc" in its name at all. It should be called something like

sgx_get_epc_page()

or so.

Now, looking at sgx_alloc_page(), it does call this one -
sgx_try_alloc_page() to get a page from the page list but it
does not allocate anything. The actual allocation happens in
sgx_alloc_epc_section() which actually does the k*alloc().

Which sounds to me like those functions should not use "alloc" and
"free" in their names but "get" and "put" to denote that they're simply
getting pages from lists and returning them back to those lists.

IMNSVHO.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 07/20] x86/sgx: Enumerate and track EPC sections
  2020-05-25  9:23   ` Borislav Petkov
@ 2020-05-27  3:56     ` Sean Christopherson
  2020-05-27 20:35       ` Borislav Petkov
  2020-05-28  5:25       ` Jarkko Sakkinen
  2020-05-28  5:13     ` Jarkko Sakkinen
  1 sibling, 2 replies; 76+ messages in thread
From: Sean Christopherson @ 2020-05-27  3:56 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: Jarkko Sakkinen, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Serge Ayoun, Jethro Beekman

On Mon, May 25, 2020 at 11:23:04AM +0200, Borislav Petkov wrote:
> On Fri, May 15, 2020 at 03:43:57AM +0300, Jarkko Sakkinen wrote:
> > +struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
> > +int sgx_nr_epc_sections;
> 
> We have become very averse against global stuff. What is going to use
> those, only sgx code I assume...?

Yes, only SGX code.  The reclaim/swap code needs access to the sections,
and that code is in a different file, reclaim.c.  I don't have a super
strong objection to sucking reclaim.c into main.c, but I'm somewhat
indifferent on code organization as a whole.  Jarkko likely has a stronger
opinion.

> > +static bool __init sgx_page_cache_init(void)
> > +{
> > +	u32 eax, ebx, ecx, edx, type;
> > +	u64 pa, size;
> > +	int i;
> > +
> > +	for (i = 0; i <= ARRAY_SIZE(sgx_epc_sections); i++) {
> > +		cpuid_count(SGX_CPUID, i + SGX_CPUID_FIRST_VARIABLE_SUB_LEAF,
> > +			    &eax, &ebx, &ecx, &edx);
> > +
> > +		type = eax & SGX_CPUID_SUB_LEAF_TYPE_MASK;
> > +		if (type == SGX_CPUID_SUB_LEAF_INVALID)
> > +			break;
> > +
> > +		if (type != SGX_CPUID_SUB_LEAF_EPC_SECTION) {
> > +			pr_err_once("Unknown EPC section type: %u\n", type);
> > +			break;
> > +		}
> > +
> > +		if (i == ARRAY_SIZE(sgx_epc_sections)) {
> > +			pr_warn("No free slot for an EPC section\n");
> > +			break;
> > +		}
> 
> This is also the loop termination: do we really need this warn or can
> the loop simply do "i < ARRAY_SIZE" ?

The warn alerts the user that there will effectively be lost/unused memory,
so IMO it's worth keeping.
 
> If the warn is needed, it can be after the loop too.
> > +
> > +		pa = sgx_calc_section_metric(eax, ebx);
> > +		size = sgx_calc_section_metric(ecx, edx);
> > +
> > +		pr_info("EPC section 0x%llx-0x%llx\n", pa, pa + size - 1);
> 
> I'm assuming that's useful information to issue in dmesg?

Yes, it's effectively the equivalent of dumping the e820 tables.  It might
not be as useful now that the code is stable, but I suspect it will come in
handy for debug/triage down the road.
 
> > diff --git a/arch/x86/kernel/cpu/sgx/reclaim.c b/arch/x86/kernel/cpu/sgx/reclaim.c
> > new file mode 100644
> > index 000000000000..215371588a25
> > --- /dev/null
> > +++ b/arch/x86/kernel/cpu/sgx/reclaim.c
> > @@ -0,0 +1,82 @@
> > +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
> > +// Copyright(c) 2016-19 Intel Corporation.
> > +
> > +#include <linux/freezer.h>
> > +#include <linux/highmem.h>
> > +#include <linux/kthread.h>
> > +#include <linux/pagemap.h>
> > +#include <linux/ratelimit.h>
> > +#include <linux/slab.h>
> > +#include <linux/sched/mm.h>
> > +#include <linux/sched/signal.h>
> > +#include "encls.h"
> > +
> > +struct task_struct *ksgxswapd_tsk;
> 
> Same for this one: also shared only among sgx code?

Yes, that one can definitely be buried behind a helper.

> > +/**
> > + * enum sgx_epc_page_desc - bits and masks for an EPC page's descriptor
> > + * %SGX_EPC_SECTION_MASK:	SGX allows to have multiple EPC sections in the
> > + *				physical memory. The existing and near-future
> > + *				hardware defines at most eight sections, hence
> > + *				three bits to hold a section.
> > + */
> > +enum sgx_epc_page_desc {
> > +	SGX_EPC_SECTION_MASK			= GENMASK_ULL(3, 0),
> 
> If that should be three bits, then it should be (2, 0). Because now you
> have 4 bits:

Apparently even pre-school math is hard these days.  I'm pretty sure that's
an ongoing brain fart, I don't think we ever conciously bumped it to 4 bits.

That being said, using 4 bits (or even 5+) isn't necessary a bad thing.  We
aren't tight on bits and the burned memory isn't awful, e.g. <100 bytes per
unused section.  Not having to update the kernel just to handle a system
with more EPC sections would be nice, though we (Intel) should check on our
end to see if nearish-future CPUs are still hard limited to eight sections.

One idea would be to provide a Kconfig a la NR_CPUS or NODES_SHIFT.  I.e.
carve out the bits in sgx_epc_page_desc to allow up to N sections, but let
the user limit the number of sections to recoup the unused memory.

> # arch/x86/kernel/cpu/sgx/sgx.h:56:     return &sgx_epc_sections[page->desc & SGX_EPC_SECTION_MASK];
>         andl    $15, %edx       #, _22
> 		^^^
> 
> > +	/* bits 12-63 are reserved for the physical page address of the page */
> > +};

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
  2020-05-26 12:52   ` Borislav Petkov
@ 2020-05-27  4:21     ` Sean Christopherson
  2020-05-27 20:46       ` Borislav Petkov
  0 siblings, 1 reply; 76+ messages in thread
From: Sean Christopherson @ 2020-05-27  4:21 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: Jarkko Sakkinen, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Jethro Beekman

On Tue, May 26, 2020 at 02:52:08PM +0200, Borislav Petkov wrote:
> On Fri, May 15, 2020 at 03:43:58AM +0300, Jarkko Sakkinen wrote:
> > diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
> > index 38424c1e8341..60d82e7537c8 100644
> > --- a/arch/x86/kernel/cpu/sgx/main.c
> > +++ b/arch/x86/kernel/cpu/sgx/main.c
> > @@ -13,6 +13,66 @@
> >  struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
> >  int sgx_nr_epc_sections;
> >  
> > +static struct sgx_epc_page *__sgx_try_alloc_page(struct sgx_epc_section *section)
> > +{
> > +	struct sgx_epc_page *page;
> > +
> > +	if (list_empty(&section->page_list))
> > +		return NULL;
> > +
> > +	page = list_first_entry(&section->page_list, struct sgx_epc_page, list);
> > +	list_del_init(&page->list);
> > +	return page;
> > +}
> > +
> > +/**
> > + * sgx_try_alloc_page() - Allocate an EPC page
> 
> Uuh, this is confusing. Looking forward into the patchset, you guys have
> 
> sgx_alloc_page()
> sgx_alloc_va_page()
>
> and this here
> 
> sgx_try_alloc_page()
> 
> So this one here should be called sgx_alloc_epc_page() if we're going to
> differentiate *what* it is allocating.

No objection to the rename.

> But then looking at sgx_alloc_page():
> 
> + * sgx_alloc_page() - Allocate an EPC page
> ...
> 
> + struct sgx_epc_page *sgx_alloc_page(void *owner, bool reclaim)
> 
> this one returns a struct sgx_epc_page * too.
> 
> The former "allocates" from the EPC cache so I'm thinking former should
> not have "alloc" in its name at all. It should be called something like
> 
> sgx_get_epc_page()
> 
> or so.

> Now, looking at sgx_alloc_page(), it does call this one -
> sgx_try_alloc_page() to get a page from the page list but it
> does not allocate anything. The actual allocation happens in
> sgx_alloc_epc_section() which actually does the k*alloc().

Ah.  The Enclave Page Cache isn't actually a cache, and it's not a kernel
construct.  The EPC is really just Enclave Memory, but Intel really likes
three letter acronyms.  On current CPUs, the EPC is carved out of main
memory via range registers, i.e. it's a statically located and sized chunk
of DRAM with special access rules that are enforced by the CPU.  It's no
more of a cache than regular DRAM. 

In other words, sgx_alloc_epc_section() is poorly named.  It doesn't
actually allocate EPC, it allocates kernel structures to map and track EPC.
sgx_(un)map_epc_section() would be more accurate and would hopefully
alleviate some of the confusion.

> Which sounds to me like those functions should not use "alloc" and
> "free" in their names but "get" and "put" to denote that they're simply
> getting pages from lists and returning them back to those lists.
> 
> IMNSVHO.

A better analogy is k*alloc() == sgx_alloc_epc_page() and
__sgx_alloc_try_alloc_page() == alloc_pages_node().  EPC sections aren't
guaranteed to have a 1:1 relationship with NUMA nodes, but that holds true
for current platforms.

I have no objection to renaming __sgx_alloc_try_alloc_page() to something
like sgx_alloc_epc_page_section or whatever, but IMO using get/put will be
horrendously confusing.

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 04/20] x86/sgx: Add SGX microarchitectural data structures
  2020-05-25  8:20           ` Borislav Petkov
@ 2020-05-27 19:43             ` Jarkko Sakkinen
  0 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-27 19:43 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: Sean Christopherson, linux-kernel, x86, linux-sgx, akpm,
	dave.hansen, nhorman, npmccallum, haitao.huang,
	andriy.shevchenko, tglx, kai.svahn, josh, luto, kai.huang,
	rientjes, cedric.xing, puiterwijk, Jethro Beekman

On Mon, 2020-05-25 at 10:20 +0200, Borislav Petkov wrote:
> On Fri, May 22, 2020 at 10:50:17PM +0300, Jarkko Sakkinen wrote:
> > If other values except two are never going to be used it is more than a
> > legit point to validate this field.
> > 
> > It also the potential to use ~0x8086 bits to be defined later if ever
> > needed lets say for some kernel specific purpose.
> 
> Yah, let's cover our ass for the future. We have all seen the "this
> won't be used" but then "we're using it" change of heart. IOW, let's
> align with what the hw checks and we can always relax that in the future
> but not the other way around.
> 
I fully agree with this conclusion and that is exactly how I think about
the issue too. I'll add a check for this.

/Jarkko


^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 07/20] x86/sgx: Enumerate and track EPC sections
  2020-05-27  3:56     ` Sean Christopherson
@ 2020-05-27 20:35       ` Borislav Petkov
  2020-05-28  7:36         ` Jarkko Sakkinen
  2020-05-28  5:25       ` Jarkko Sakkinen
  1 sibling, 1 reply; 76+ messages in thread
From: Borislav Petkov @ 2020-05-27 20:35 UTC (permalink / raw)
  To: Sean Christopherson
  Cc: Jarkko Sakkinen, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Serge Ayoun, Jethro Beekman

On Tue, May 26, 2020 at 08:56:14PM -0700, Sean Christopherson wrote:
> > > +		if (i == ARRAY_SIZE(sgx_epc_sections)) {
> > > +			pr_warn("No free slot for an EPC section\n");
> > > +			break;
> > > +		}
> > 
> > This is also the loop termination: do we really need this warn or can
> > the loop simply do "i < ARRAY_SIZE" ?
> 
> The warn alerts the user that there will effectively be lost/unused memory,
> so IMO it's worth keeping.

Can the user do anything about it? If not, then probably no need to say
anything.

> > > +		pr_info("EPC section 0x%llx-0x%llx\n", pa, pa + size - 1);
> > 
> > I'm assuming that's useful information to issue in dmesg?
> 
> Yes, it's effectively the equivalent of dumping the e820 tables.  It might
> not be as useful now that the code is stable, but I suspect it will come in
> handy for debug/triage down the road.

Ok.

> > Same for this one: also shared only among sgx code?
> 
> Yes, that one can definitely be buried behind a helper.

Shared only within sgx is fine. 

<snip> 

> One idea would be to provide a Kconfig a la NR_CPUS or NODES_SHIFT.  I.e.
> carve out the bits in sgx_epc_page_desc to allow up to N sections, but let
> the user limit the number of sections to recoup the unused memory.

I'd prefer a good estimate of a highest value, say 8 bits, which should
suffice for the foreseeable future. That's the simplest thing to do and
our Kconfig symbols space is an abomination of gazillion symbols.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
  2020-05-27  4:21     ` Sean Christopherson
@ 2020-05-27 20:46       ` Borislav Petkov
  2020-05-28  0:52         ` Sean Christopherson
  2020-05-28  1:23         ` Jarkko Sakkinen
  0 siblings, 2 replies; 76+ messages in thread
From: Borislav Petkov @ 2020-05-27 20:46 UTC (permalink / raw)
  To: Sean Christopherson
  Cc: Jarkko Sakkinen, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Jethro Beekman

On Tue, May 26, 2020 at 09:21:11PM -0700, Sean Christopherson wrote:
> In other words, sgx_alloc_epc_section() is poorly named.  It doesn't
> actually allocate EPC, it allocates kernel structures to map and track EPC.
> sgx_(un)map_epc_section() would be more accurate and would hopefully
> alleviate some of the confusion.

Makes sense.

> I have no objection to renaming __sgx_alloc_try_alloc_page() to something
> like sgx_alloc_epc_page_section or whatever, but IMO using get/put will be
> horrendously confusing.

Ok. My only issue is that the naming nomenclature sounds strange and
confusing as it is. "try" in an "alloc" function is kinda tautological -
of course the function will try to do its best. :)

And there are three functions having "alloc" in the name so I can
imagine someone getting very confused when having to stare at that code.

So at least naming them in a way so that it is clear what kind of pages
they "allocate" - i.e., what they actually do - would be a step in the
right direction...

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
  2020-05-27 20:46       ` Borislav Petkov
@ 2020-05-28  0:52         ` Sean Christopherson
  2020-05-28  6:51           ` Jarkko Sakkinen
  2020-05-28  1:23         ` Jarkko Sakkinen
  1 sibling, 1 reply; 76+ messages in thread
From: Sean Christopherson @ 2020-05-28  0:52 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: Jarkko Sakkinen, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Jethro Beekman

On Wed, May 27, 2020 at 10:46:38PM +0200, Borislav Petkov wrote:
> On Tue, May 26, 2020 at 09:21:11PM -0700, Sean Christopherson wrote:
> > In other words, sgx_alloc_epc_section() is poorly named.  It doesn't
> > actually allocate EPC, it allocates kernel structures to map and track EPC.
> > sgx_(un)map_epc_section() would be more accurate and would hopefully
> > alleviate some of the confusion.
> 
> Makes sense.
> 
> > I have no objection to renaming __sgx_alloc_try_alloc_page() to something
> > like sgx_alloc_epc_page_section or whatever, but IMO using get/put will be
> > horrendously confusing.
> 
> Ok. My only issue is that the naming nomenclature sounds strange and
> confusing as it is. "try" in an "alloc" function is kinda tautological -
> of course the function will try to do its best. :)

Heh, so what you're saying is we should add __sgx_really_try_alloc_page()?

> And there are three functions having "alloc" in the name so I can
> imagine someone getting very confused when having to stare at that code.
> 
> So at least naming them in a way so that it is clear what kind of pages
> they "allocate" - i.e., what they actually do - would be a step in the
> right direction...

Ya, and things will only get more confusing when actual NUMA awareness gets
thrown into the mix.

Jarkko, splicing in the NUMA awareness code, what do you think about:

  sgx_alloc_epc_section -> sgx_map_epc_section
  sgx_free_epc_section  -> sgx_unmap_epc_section

  sgx_alloc_page        -> sgx_alloc_epc_page
  sgx_free_page         -> sgx_free_epc_page

  sgx_try_alloc_page    -> sgx_alloc_epc_page_node
  __sgx_try_alloc_page  -> sgx_alloc_epc_page_section

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
  2020-05-27 20:46       ` Borislav Petkov
  2020-05-28  0:52         ` Sean Christopherson
@ 2020-05-28  1:23         ` Jarkko Sakkinen
  2020-05-28  1:36           ` Sean Christopherson
  1 sibling, 1 reply; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-28  1:23 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: Sean Christopherson, linux-kernel, x86, linux-sgx, akpm,
	dave.hansen, nhorman, npmccallum, haitao.huang,
	andriy.shevchenko, tglx, kai.svahn, josh, luto, kai.huang,
	rientjes, cedric.xing, puiterwijk, Jethro Beekman


[-- Attachment #1: Type: text/plain, Size: 1651 bytes --]

On Wed, May 27, 2020 at 10:46:38PM +0200, Borislav Petkov wrote:
> On Tue, May 26, 2020 at 09:21:11PM -0700, Sean Christopherson wrote:
> > In other words, sgx_alloc_epc_section() is poorly named.  It doesn't
> > actually allocate EPC, it allocates kernel structures to map and track EPC.
> > sgx_(un)map_epc_section() would be more accurate and would hopefully
> > alleviate some of the confusion.
> 
> Makes sense.
> 
> > I have no objection to renaming __sgx_alloc_try_alloc_page() to something
> > like sgx_alloc_epc_page_section or whatever, but IMO using get/put will be
> > horrendously confusing.
> 
> Ok. My only issue is that the naming nomenclature sounds strange and
> confusing as it is. "try" in an "alloc" function is kinda tautological -
> of course the function will try to do its best. :)
> 
> And there are three functions having "alloc" in the name so I can
> imagine someone getting very confused when having to stare at that code.
> 
> So at least naming them in a way so that it is clear what kind of pages
> they "allocate" - i.e., what they actually do - would be a step in the
> right direction...
> 
> Thx.

I also think sgx_get_epc_page() is also kind of confusing name. The
reason is that "get" can many things.

I'm not sure I follow fully Sean's reasoning but the way alloc is used
mostly in Linux is to ask through some API the used kernel memory
allocator to give memory for some kernel data structures.

Agreed that it is not the best match on what we are doing.

The first common verb that comes to my mind about the action taken is
grabbing. Attached a patch reflecting this idea that I'm ready to
squash.

/Jarkko

[-- Attachment #2: 0001-x86-sgx-sgx_alloc_page-to-sgx_grab_page.patch --]
[-- Type: text/x-diff, Size: 5256 bytes --]

From 2598b920fc917790966ba314a2df524ff4695c75 Mon Sep 17 00:00:00 2001
From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Date: Thu, 28 May 2020 04:21:08 +0300
Subject: [PATCH] x86/sgx: sgx_alloc_page() to sgx_grab_page()

$ git  grep -l sgx_alloc_page | xargs sed -i 's/sgx_alloc_page/sgx_grab_page/g'
$ git  grep -l sgx_try_alloc_page | xargs sed -i 's/sgx_try_alloc_page/sgx_try_grab_page/g'

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 arch/x86/kernel/cpu/sgx/encl.c  |  6 +++---
 arch/x86/kernel/cpu/sgx/ioctl.c |  4 ++--
 arch/x86/kernel/cpu/sgx/main.c  | 14 +++++++-------
 arch/x86/kernel/cpu/sgx/sgx.h   |  4 ++--
 4 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
index c070aa90b5fe..fab2a8aec410 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -67,7 +67,7 @@ static struct sgx_epc_page *sgx_encl_eldu(struct sgx_encl_page *encl_page,
 	struct sgx_epc_page *epc_page;
 	int ret;
 
-	epc_page = sgx_alloc_page(encl_page, false);
+	epc_page = sgx_grab_page(encl_page, false);
 	if (IS_ERR(epc_page))
 		return epc_page;
 
@@ -686,7 +686,7 @@ struct sgx_encl_page *sgx_encl_reserve_page(struct sgx_encl *encl,
 }
 
 /**
- * sgx_alloc_page - allocate a VA page
+ * sgx_grab_page - allocate a VA page
  *
  * Allocates an &sgx_epc_page instance and converts it to a VA page.
  *
@@ -699,7 +699,7 @@ struct sgx_epc_page *sgx_alloc_va_page(void)
 	struct sgx_epc_page *epc_page;
 	int ret;
 
-	epc_page = sgx_alloc_page(NULL, true);
+	epc_page = sgx_grab_page(NULL, true);
 	if (IS_ERR(epc_page))
 		return ERR_CAST(epc_page);
 
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index 81b6c5d64c96..c880dc40310c 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -183,7 +183,7 @@ static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
 
 	encl->backing = backing;
 
-	secs_epc = sgx_alloc_page(&encl->secs, true);
+	secs_epc = sgx_grab_page(&encl->secs, true);
 	if (IS_ERR(secs_epc)) {
 		ret = PTR_ERR(secs_epc);
 		goto err_out_backing;
@@ -376,7 +376,7 @@ static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long src,
 	if (IS_ERR(encl_page))
 		return PTR_ERR(encl_page);
 
-	epc_page = sgx_alloc_page(encl_page, true);
+	epc_page = sgx_grab_page(encl_page, true);
 	if (IS_ERR(epc_page)) {
 		kfree(encl_page);
 		return PTR_ERR(epc_page);
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 5ce77e554676..b5cd941861bc 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -14,7 +14,7 @@
 struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
 int sgx_nr_epc_sections;
 
-static struct sgx_epc_page *__sgx_try_alloc_page(struct sgx_epc_section *section)
+static struct sgx_epc_page *__sgx_try_grab_page(struct sgx_epc_section *section)
 {
 	struct sgx_epc_page *page;
 
@@ -29,7 +29,7 @@ static struct sgx_epc_page *__sgx_try_alloc_page(struct sgx_epc_section *section
 }
 
 /**
- * sgx_try_alloc_page() - Allocate an EPC page
+ * sgx_try_grab_page() - Allocate an EPC page
  *
  * Try to grab a page from the free EPC page list.
  *
@@ -37,7 +37,7 @@ static struct sgx_epc_page *__sgx_try_alloc_page(struct sgx_epc_section *section
  *   a pointer to a &struct sgx_epc_page instance,
  *   -errno on error
  */
-struct sgx_epc_page *sgx_try_alloc_page(void)
+struct sgx_epc_page *sgx_try_grab_page(void)
 {
 	struct sgx_epc_section *section;
 	struct sgx_epc_page *page;
@@ -46,7 +46,7 @@ struct sgx_epc_page *sgx_try_alloc_page(void)
 	for (i = 0; i < sgx_nr_epc_sections; i++) {
 		section = &sgx_epc_sections[i];
 		spin_lock(&section->lock);
-		page = __sgx_try_alloc_page(section);
+		page = __sgx_try_grab_page(section);
 		spin_unlock(&section->lock);
 
 		if (page)
@@ -57,7 +57,7 @@ struct sgx_epc_page *sgx_try_alloc_page(void)
 }
 
 /**
- * sgx_alloc_page() - Allocate an EPC page
+ * sgx_grab_page() - Allocate an EPC page
  * @owner:	the owner of the EPC page
  * @reclaim:	reclaim pages if necessary
  *
@@ -69,12 +69,12 @@ struct sgx_epc_page *sgx_try_alloc_page(void)
  *   a pointer to a &struct sgx_epc_page instance,
  *   -errno on error
  */
-struct sgx_epc_page *sgx_alloc_page(void *owner, bool reclaim)
+struct sgx_epc_page *sgx_grab_page(void *owner, bool reclaim)
 {
 	struct sgx_epc_page *entry;
 
 	for ( ; ; ) {
-		entry = sgx_try_alloc_page();
+		entry = sgx_try_grab_page();
 		if (!IS_ERR(entry)) {
 			entry->owner = owner;
 			break;
diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h
index 0c481e6f2c95..84198c17e766 100644
--- a/arch/x86/kernel/cpu/sgx/sgx.h
+++ b/arch/x86/kernel/cpu/sgx/sgx.h
@@ -101,8 +101,8 @@ void sgx_mark_page_reclaimable(struct sgx_epc_page *page);
 int sgx_unmark_page_reclaimable(struct sgx_epc_page *page);
 void sgx_reclaim_pages(void);
 
-struct sgx_epc_page *sgx_try_alloc_page(void);
-struct sgx_epc_page *sgx_alloc_page(void *owner, bool reclaim);
+struct sgx_epc_page *sgx_try_grab_page(void);
+struct sgx_epc_page *sgx_grab_page(void *owner, bool reclaim);
 void sgx_free_page(struct sgx_epc_page *page);
 
 #endif /* _X86_SGX_H */
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
  2020-05-28  1:23         ` Jarkko Sakkinen
@ 2020-05-28  1:36           ` Sean Christopherson
  2020-05-28  6:52             ` Jarkko Sakkinen
  0 siblings, 1 reply; 76+ messages in thread
From: Sean Christopherson @ 2020-05-28  1:36 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: Borislav Petkov, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Jethro Beekman

On Thu, May 28, 2020 at 04:23:19AM +0300, Jarkko Sakkinen wrote:
> On Wed, May 27, 2020 at 10:46:38PM +0200, Borislav Petkov wrote:
> > On Tue, May 26, 2020 at 09:21:11PM -0700, Sean Christopherson wrote:
> > > In other words, sgx_alloc_epc_section() is poorly named.  It doesn't
> > > actually allocate EPC, it allocates kernel structures to map and track EPC.
> > > sgx_(un)map_epc_section() would be more accurate and would hopefully
> > > alleviate some of the confusion.

...

> I'm not sure I follow fully Sean's reasoning but the way alloc is used
> mostly in Linux is to ask through some API the used kernel memory
> allocator to give memory for some kernel data structures.

Function names are usually some form of

  <namespace>_<verb>_<object>

where 'object' is the target of the 'verb'.  So sgx_alloc_epc_section()
is most likely going to be read as "SGX, allocate an EPC section".  But
that code doesn't allocate an EPC section, it maps an EPC section, and on
success, adds the section's pages to the unsanitized list, i.e. what
effectively becomes the pool of EPC pages.  The allocation part is a side
effect of how we track EPC pages, it's not the primary purpose of the
function.

Maybe sgx_add_epc_section() and sgx_remove_epc_section() would be better
than map/unmap?

Eliminating the misnamed sgx_alloc_epc_section() frees up the "alloc" verb
for use in the actual EPC page allocation paths, i.e. avoids having to
rename those to "grab".  IMO, "alloc" is the best name as it most closely
aligns with the nomenclature for regular pages, e.g. "grab" is most often
used to elevate refcounts.

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 07/20] x86/sgx: Enumerate and track EPC sections
  2020-05-25  9:23   ` Borislav Petkov
  2020-05-27  3:56     ` Sean Christopherson
@ 2020-05-28  5:13     ` Jarkko Sakkinen
  1 sibling, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-28  5:13 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	sean.j.christopherson, nhorman, npmccallum, haitao.huang,
	andriy.shevchenko, tglx, kai.svahn, josh, luto, kai.huang,
	rientjes, cedric.xing, puiterwijk, Serge Ayoun, Jethro Beekman

On Mon, May 25, 2020 at 11:23:04AM +0200, Borislav Petkov wrote:
> Enabling this gives:
> 
> In file included from arch/x86/kernel/cpu/sgx/main.c:11:
> arch/x86/kernel/cpu/sgx/encls.h:189:51: warning: ‘struct sgx_einittoken’ declared inside parameter list will not be visible outside of this definition or declaration
>   189 | static inline int __einit(void *sigstruct, struct sgx_einittoken *einittoken,
>       |                                                   ^~~~~~~~~~~~~~
> In file included from arch/x86/kernel/cpu/sgx/reclaim.c:12:
> arch/x86/kernel/cpu/sgx/encls.h:189:51: warning: ‘struct sgx_einittoken’ declared inside parameter list will not be visible outside of this definition or declaration
>   189 | static inline int __einit(void *sigstruct, struct sgx_einittoken *einittoken,
>       |
> 
> You need a forward declaration somewhere.

It is a left-over from v28 and should be "void *".

To backtrack what happened it looks that I squashed the change that
does this to "x86/sgx: Linux Enclave Driver".

This is fixed now in my tree.

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 07/20] x86/sgx: Enumerate and track EPC sections
  2020-05-27  3:56     ` Sean Christopherson
  2020-05-27 20:35       ` Borislav Petkov
@ 2020-05-28  5:25       ` Jarkko Sakkinen
  2020-05-28  5:35         ` Jarkko Sakkinen
  1 sibling, 1 reply; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-28  5:25 UTC (permalink / raw)
  To: Sean Christopherson
  Cc: Borislav Petkov, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Serge Ayoun, Jethro Beekman

On Tue, May 26, 2020 at 08:56:14PM -0700, Sean Christopherson wrote:
> On Mon, May 25, 2020 at 11:23:04AM +0200, Borislav Petkov wrote:
> > On Fri, May 15, 2020 at 03:43:57AM +0300, Jarkko Sakkinen wrote:
> > > +struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
> > > +int sgx_nr_epc_sections;
> > 
> > We have become very averse against global stuff. What is going to use
> > those, only sgx code I assume...?
> 
> Yes, only SGX code.  The reclaim/swap code needs access to the sections,
> and that code is in a different file, reclaim.c.  I don't have a super
> strong objection to sucking reclaim.c into main.c, but I'm somewhat
> indifferent on code organization as a whole.  Jarkko likely has a stronger
> opinion.

I'll change it.

It's not quite as easy as just "sucking the file in". All the commits
that touch the file need to be reworked:

$ git --no-pager log --format="%H %s" arch/x86/kernel/cpu/sgx/reclaim.c
5aeca6dabf767e9350ee3188ba25ceb21f3162b4 x86/sgx: Add a page reclaimer
de9b1088959f36ffdaf43a49bfea1c7f9f81cac7 x86/sgx: Linux Enclave Driver
08d8fcb74fe268059ee58fcc2a0833b244e1f22a x86/sgx: Enumerate and track EPC sections

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 07/20] x86/sgx: Enumerate and track EPC sections
  2020-05-28  5:25       ` Jarkko Sakkinen
@ 2020-05-28  5:35         ` Jarkko Sakkinen
  2020-05-28  6:14           ` Jarkko Sakkinen
  0 siblings, 1 reply; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-28  5:35 UTC (permalink / raw)
  To: Sean Christopherson
  Cc: Borislav Petkov, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Serge Ayoun, Jethro Beekman

On Thu, May 28, 2020 at 08:25:43AM +0300, Jarkko Sakkinen wrote:
> On Tue, May 26, 2020 at 08:56:14PM -0700, Sean Christopherson wrote:
> > On Mon, May 25, 2020 at 11:23:04AM +0200, Borislav Petkov wrote:
> > > On Fri, May 15, 2020 at 03:43:57AM +0300, Jarkko Sakkinen wrote:
> > > > +struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
> > > > +int sgx_nr_epc_sections;
> > > 
> > > We have become very averse against global stuff. What is going to use
> > > those, only sgx code I assume...?
> > 
> > Yes, only SGX code.  The reclaim/swap code needs access to the sections,
> > and that code is in a different file, reclaim.c.  I don't have a super
> > strong objection to sucking reclaim.c into main.c, but I'm somewhat
> > indifferent on code organization as a whole.  Jarkko likely has a stronger
> > opinion.
> 
> I'll change it.
> 
> It's not quite as easy as just "sucking the file in". All the commits
> that touch the file need to be reworked:
> 
> $ git --no-pager log --format="%H %s" arch/x86/kernel/cpu/sgx/reclaim.c
> 5aeca6dabf767e9350ee3188ba25ceb21f3162b4 x86/sgx: Add a page reclaimer
> de9b1088959f36ffdaf43a49bfea1c7f9f81cac7 x86/sgx: Linux Enclave Driver
> 08d8fcb74fe268059ee58fcc2a0833b244e1f22a x86/sgx: Enumerate and track EPC sections

Not that I haven't done this a lot last few years. A proven approach
is to do it in two "git rebase -i mainline/master" sweeps:

1. For each commit, remove reclaim.c entry from the Makefile and import
   reclaim.c contents to main.c.
2. For each commit, delete reclaim.c.

I've tried quite a few different angles and this what I've converged
into. Very hard to hit messy into messy merge conflicts.

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 07/20] x86/sgx: Enumerate and track EPC sections
  2020-05-28  5:35         ` Jarkko Sakkinen
@ 2020-05-28  6:14           ` Jarkko Sakkinen
  2020-05-28  6:16             ` Jarkko Sakkinen
  0 siblings, 1 reply; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-28  6:14 UTC (permalink / raw)
  To: Sean Christopherson
  Cc: Borislav Petkov, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Serge Ayoun, Jethro Beekman

On Thu, May 28, 2020 at 08:35:15AM +0300, Jarkko Sakkinen wrote:
> On Thu, May 28, 2020 at 08:25:43AM +0300, Jarkko Sakkinen wrote:
> > On Tue, May 26, 2020 at 08:56:14PM -0700, Sean Christopherson wrote:
> > > On Mon, May 25, 2020 at 11:23:04AM +0200, Borislav Petkov wrote:
> > > > On Fri, May 15, 2020 at 03:43:57AM +0300, Jarkko Sakkinen wrote:
> > > > > +struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
> > > > > +int sgx_nr_epc_sections;
> > > > 
> > > > We have become very averse against global stuff. What is going to use
> > > > those, only sgx code I assume...?
> > > 
> > > Yes, only SGX code.  The reclaim/swap code needs access to the sections,
> > > and that code is in a different file, reclaim.c.  I don't have a super
> > > strong objection to sucking reclaim.c into main.c, but I'm somewhat
> > > indifferent on code organization as a whole.  Jarkko likely has a stronger
> > > opinion.
> > 
> > I'll change it.
> > 
> > It's not quite as easy as just "sucking the file in". All the commits
> > that touch the file need to be reworked:
> > 
> > $ git --no-pager log --format="%H %s" arch/x86/kernel/cpu/sgx/reclaim.c
> > 5aeca6dabf767e9350ee3188ba25ceb21f3162b4 x86/sgx: Add a page reclaimer
> > de9b1088959f36ffdaf43a49bfea1c7f9f81cac7 x86/sgx: Linux Enclave Driver
> > 08d8fcb74fe268059ee58fcc2a0833b244e1f22a x86/sgx: Enumerate and track EPC sections
> 
> Not that I haven't done this a lot last few years. A proven approach
> is to do it in two "git rebase -i mainline/master" sweeps:
> 
> 1. For each commit, remove reclaim.c entry from the Makefile and import
>    reclaim.c contents to main.c.
> 2. For each commit, delete reclaim.c.
> 
> I've tried quite a few different angles and this what I've converged
> into. Very hard to hit messy into messy merge conflicts.

Remembered why the things are the way they are. Also ioctl.c needs these
symbols and I'd keep that separate from the contents of main.c and
reclaim.c. There the separation obviously makes sense.

I'll anyway merge main.c and reclaim.c as one for v31 because they are
strongly connected.

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 07/20] x86/sgx: Enumerate and track EPC sections
  2020-05-28  6:14           ` Jarkko Sakkinen
@ 2020-05-28  6:16             ` Jarkko Sakkinen
  0 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-28  6:16 UTC (permalink / raw)
  To: Sean Christopherson
  Cc: Borislav Petkov, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Serge Ayoun, Jethro Beekman

On Thu, May 28, 2020 at 09:14:43AM +0300, Jarkko Sakkinen wrote:
> On Thu, May 28, 2020 at 08:35:15AM +0300, Jarkko Sakkinen wrote:
> > On Thu, May 28, 2020 at 08:25:43AM +0300, Jarkko Sakkinen wrote:
> > > On Tue, May 26, 2020 at 08:56:14PM -0700, Sean Christopherson wrote:
> > > > On Mon, May 25, 2020 at 11:23:04AM +0200, Borislav Petkov wrote:
> > > > > On Fri, May 15, 2020 at 03:43:57AM +0300, Jarkko Sakkinen wrote:
> > > > > > +struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
> > > > > > +int sgx_nr_epc_sections;
> > > > > 
> > > > > We have become very averse against global stuff. What is going to use
> > > > > those, only sgx code I assume...?
> > > > 
> > > > Yes, only SGX code.  The reclaim/swap code needs access to the sections,
> > > > and that code is in a different file, reclaim.c.  I don't have a super
> > > > strong objection to sucking reclaim.c into main.c, but I'm somewhat
> > > > indifferent on code organization as a whole.  Jarkko likely has a stronger
> > > > opinion.
> > > 
> > > I'll change it.
> > > 
> > > It's not quite as easy as just "sucking the file in". All the commits
> > > that touch the file need to be reworked:
> > > 
> > > $ git --no-pager log --format="%H %s" arch/x86/kernel/cpu/sgx/reclaim.c
> > > 5aeca6dabf767e9350ee3188ba25ceb21f3162b4 x86/sgx: Add a page reclaimer
> > > de9b1088959f36ffdaf43a49bfea1c7f9f81cac7 x86/sgx: Linux Enclave Driver
> > > 08d8fcb74fe268059ee58fcc2a0833b244e1f22a x86/sgx: Enumerate and track EPC sections
> > 
> > Not that I haven't done this a lot last few years. A proven approach
> > is to do it in two "git rebase -i mainline/master" sweeps:
> > 
> > 1. For each commit, remove reclaim.c entry from the Makefile and import
> >    reclaim.c contents to main.c.
> > 2. For each commit, delete reclaim.c.
> > 
> > I've tried quite a few different angles and this what I've converged
> > into. Very hard to hit messy into messy merge conflicts.
> 
> Remembered why the things are the way they are. Also ioctl.c needs these
> symbols and I'd keep that separate from the contents of main.c and
> reclaim.c. There the separation obviously makes sense.
> 
> I'll anyway merge main.c and reclaim.c as one for v31 because they are
> strongly connected.

And more importantly for the reason that it allows to make ksgxswapd_tsk
making the whole thing way more cleaner.

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
  2020-05-28  0:52         ` Sean Christopherson
@ 2020-05-28  6:51           ` Jarkko Sakkinen
  0 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-28  6:51 UTC (permalink / raw)
  To: Sean Christopherson
  Cc: Borislav Petkov, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Jethro Beekman

On Wed, May 27, 2020 at 05:52:17PM -0700, Sean Christopherson wrote:
> On Wed, May 27, 2020 at 10:46:38PM +0200, Borislav Petkov wrote:
> > On Tue, May 26, 2020 at 09:21:11PM -0700, Sean Christopherson wrote:
> > > In other words, sgx_alloc_epc_section() is poorly named.  It doesn't
> > > actually allocate EPC, it allocates kernel structures to map and track EPC.
> > > sgx_(un)map_epc_section() would be more accurate and would hopefully
> > > alleviate some of the confusion.
> > 
> > Makes sense.
> > 
> > > I have no objection to renaming __sgx_alloc_try_alloc_page() to something
> > > like sgx_alloc_epc_page_section or whatever, but IMO using get/put will be
> > > horrendously confusing.
> > 
> > Ok. My only issue is that the naming nomenclature sounds strange and
> > confusing as it is. "try" in an "alloc" function is kinda tautological -
> > of course the function will try to do its best. :)
> 
> Heh, so what you're saying is we should add __sgx_really_try_alloc_page()?
> 
> > And there are three functions having "alloc" in the name so I can
> > imagine someone getting very confused when having to stare at that code.
> > 
> > So at least naming them in a way so that it is clear what kind of pages
> > they "allocate" - i.e., what they actually do - would be a step in the
> > right direction...
> 
> Ya, and things will only get more confusing when actual NUMA awareness gets
> thrown into the mix.
> 
> Jarkko, splicing in the NUMA awareness code, what do you think about:
> 
>   sgx_alloc_epc_section -> sgx_map_epc_section
>   sgx_free_epc_section  -> sgx_unmap_epc_section

Here alloc makes sense because memory gets allocated for the data
structures.

>   sgx_alloc_page        -> sgx_alloc_epc_page
>   sgx_free_page         -> sgx_free_epc_page
> 
>   sgx_try_alloc_page    -> sgx_alloc_epc_page_node
>   __sgx_try_alloc_page  -> sgx_alloc_epc_page_section

I'm going with sgx_grab_page() and sgx_try_grab_page().

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
  2020-05-28  1:36           ` Sean Christopherson
@ 2020-05-28  6:52             ` Jarkko Sakkinen
  2020-05-28 17:16               ` Borislav Petkov
  0 siblings, 1 reply; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-28  6:52 UTC (permalink / raw)
  To: Sean Christopherson
  Cc: Borislav Petkov, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Jethro Beekman

On Wed, May 27, 2020 at 06:36:18PM -0700, Sean Christopherson wrote:
> On Thu, May 28, 2020 at 04:23:19AM +0300, Jarkko Sakkinen wrote:
> > On Wed, May 27, 2020 at 10:46:38PM +0200, Borislav Petkov wrote:
> > > On Tue, May 26, 2020 at 09:21:11PM -0700, Sean Christopherson wrote:
> > > > In other words, sgx_alloc_epc_section() is poorly named.  It doesn't
> > > > actually allocate EPC, it allocates kernel structures to map and track EPC.
> > > > sgx_(un)map_epc_section() would be more accurate and would hopefully
> > > > alleviate some of the confusion.
> 
> ...
> 
> > I'm not sure I follow fully Sean's reasoning but the way alloc is used
> > mostly in Linux is to ask through some API the used kernel memory
> > allocator to give memory for some kernel data structures.
> 
> Function names are usually some form of
> 
>   <namespace>_<verb>_<object>
> 
> where 'object' is the target of the 'verb'.  So sgx_alloc_epc_section()
> is most likely going to be read as "SGX, allocate an EPC section".  But
> that code doesn't allocate an EPC section, it maps an EPC section, and on
> success, adds the section's pages to the unsanitized list, i.e. what
> effectively becomes the pool of EPC pages.  The allocation part is a side
> effect of how we track EPC pages, it's not the primary purpose of the
> function.
> 
> Maybe sgx_add_epc_section() and sgx_remove_epc_section() would be better
> than map/unmap?
> 
> Eliminating the misnamed sgx_alloc_epc_section() frees up the "alloc" verb
> for use in the actual EPC page allocation paths, i.e. avoids having to
> rename those to "grab".  IMO, "alloc" is the best name as it most closely
> aligns with the nomenclature for regular pages, e.g. "grab" is most often
> used to elevate refcounts.

I'm thinking that you are over-engineering something this :-) Naming is
never perfect.

But I do get the original comment about sgx_alloc_page().

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 07/20] x86/sgx: Enumerate and track EPC sections
  2020-05-27 20:35       ` Borislav Petkov
@ 2020-05-28  7:36         ` Jarkko Sakkinen
  0 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-28  7:36 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: Sean Christopherson, linux-kernel, x86, linux-sgx, akpm,
	dave.hansen, nhorman, npmccallum, haitao.huang,
	andriy.shevchenko, tglx, kai.svahn, josh, luto, kai.huang,
	rientjes, cedric.xing, puiterwijk, Serge Ayoun, Jethro Beekman

On Wed, May 27, 2020 at 10:35:09PM +0200, Borislav Petkov wrote:
 
> > One idea would be to provide a Kconfig a la NR_CPUS or NODES_SHIFT.  I.e.
> > carve out the bits in sgx_epc_page_desc to allow up to N sections, but let
> > the user limit the number of sections to recoup the unused memory.
> 
> I'd prefer a good estimate of a highest value, say 8 bits, which should
> suffice for the foreseeable future. That's the simplest thing to do and
> our Kconfig symbols space is an abomination of gazillion symbols.

OK, will do.

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
  2020-05-28  6:52             ` Jarkko Sakkinen
@ 2020-05-28 17:16               ` Borislav Petkov
  2020-05-28 17:19                 ` Sean Christopherson
  2020-05-28 19:07                 ` Jarkko Sakkinen
  0 siblings, 2 replies; 76+ messages in thread
From: Borislav Petkov @ 2020-05-28 17:16 UTC (permalink / raw)
  To: Jarkko Sakkinen, Sean Christopherson
  Cc: linux-kernel, x86, linux-sgx, akpm, dave.hansen, nhorman,
	npmccallum, haitao.huang, andriy.shevchenko, tglx, kai.svahn,
	josh, luto, kai.huang, rientjes, cedric.xing, puiterwijk,
	Jethro Beekman

Lemme reply to all mails with one. :-)

I think Sean almost had it:

>  sgx_alloc_epc_section -> sgx_map_epc_section
>  sgx_free_epc_section  -> sgx_unmap_epc_section

Or even

  sgx_setup_epc_section()
  sgx_free_epc_section()

>  sgx_alloc_page        -> sgx_alloc_epc_page
>  sgx_free_page         -> sgx_free_epc_page
>
>  sgx_try_alloc_page    -> sgx_alloc_epc_page_node
>  __sgx_try_alloc_page  -> sgx_alloc_epc_page_section

And except those last two. Those are allocating a page from the EPC
sections so I'd call them:

sgx_try_alloc_page    -> sgx_alloc_epc_page_section
__sgx_try_alloc_page  -> __sgx_alloc_epc_page_section

former doing the loop, latter doing the per-section list games.

> I'm not sure I follow fully Sean's reasoning but the way alloc is used
> mostly in Linux is to ask through some API the used kernel memory
> allocator to give memory for some kernel data structures.
>
> Agreed that it is not the best match on what we are doing.

Yes, ok, let's stay with "alloc". Agreed.

> I'm going with sgx_grab_page() and sgx_try_grab_page().

And let's simply forget the "try" - all the functions that can fail and
return an error code, they all try. :-)

> So sgx_alloc_epc_section() is most likely going to be read as "SGX,
> allocate an EPC section".

Or, allocate *from* the EPC section if it returns a pointer to a page
and the comment above it says so...

So to sum up:

* sgx_{alloc,setup}_epc_section - sets up the EPC section and the pages
which belong to it.

* sgx_alloc_page - allocates an EPC page

* sgx_alloc_epc_page_section - allocates a page from any EPC section

I think that makes it pretty clear what each function does...

> I'm thinking that you are over-engineering something this :-) Naming is
> never perfect.

I know, but naming stuff right will pay off later.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
  2020-05-28 17:16               ` Borislav Petkov
@ 2020-05-28 17:19                 ` Sean Christopherson
  2020-05-28 17:27                   ` Borislav Petkov
  2020-05-28 19:07                 ` Jarkko Sakkinen
  1 sibling, 1 reply; 76+ messages in thread
From: Sean Christopherson @ 2020-05-28 17:19 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: Jarkko Sakkinen, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Jethro Beekman

On Thu, May 28, 2020 at 07:16:35PM +0200, Borislav Petkov wrote:
> * sgx_alloc_page - allocates an EPC page

Did you want this to be sgx_alloc_epc_page?

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
  2020-05-28 17:19                 ` Sean Christopherson
@ 2020-05-28 17:27                   ` Borislav Petkov
  2020-05-28 17:34                     ` Sean Christopherson
  0 siblings, 1 reply; 76+ messages in thread
From: Borislav Petkov @ 2020-05-28 17:27 UTC (permalink / raw)
  To: Sean Christopherson
  Cc: Jarkko Sakkinen, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Jethro Beekman

On Thu, May 28, 2020 at 10:19:37AM -0700, Sean Christopherson wrote:
> On Thu, May 28, 2020 at 07:16:35PM +0200, Borislav Petkov wrote:
> > * sgx_alloc_page - allocates an EPC page
> 
> Did you want this to be sgx_alloc_epc_page?

Whatever you guys prefer. I'd use "sgx_alloc_page" because it returns
struct sgx_epc_page * but having "epc" in the name makes it even more
explicit so either is just fine.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
  2020-05-28 17:27                   ` Borislav Petkov
@ 2020-05-28 17:34                     ` Sean Christopherson
  0 siblings, 0 replies; 76+ messages in thread
From: Sean Christopherson @ 2020-05-28 17:34 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: Jarkko Sakkinen, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Jethro Beekman

On Thu, May 28, 2020 at 07:27:24PM +0200, Borislav Petkov wrote:
> On Thu, May 28, 2020 at 10:19:37AM -0700, Sean Christopherson wrote:
> > On Thu, May 28, 2020 at 07:16:35PM +0200, Borislav Petkov wrote:
> > > * sgx_alloc_page - allocates an EPC page
> > 
> > Did you want this to be sgx_alloc_epc_page?
> 
> Whatever you guys prefer. I'd use "sgx_alloc_page" because it returns
> struct sgx_epc_page * but having "epc" in the name makes it even more
> explicit so either is just fine.

sgx_alloc_page() works for me, I just wanted to make sure it wasn't a typo.

Thanks!

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
  2020-05-28 17:16               ` Borislav Petkov
  2020-05-28 17:19                 ` Sean Christopherson
@ 2020-05-28 19:07                 ` Jarkko Sakkinen
  2020-05-28 19:59                   ` Sean Christopherson
  1 sibling, 1 reply; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-28 19:07 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: Sean Christopherson, linux-kernel, x86, linux-sgx, akpm,
	dave.hansen, nhorman, npmccallum, haitao.huang,
	andriy.shevchenko, tglx, kai.svahn, josh, luto, kai.huang,
	rientjes, cedric.xing, puiterwijk, Jethro Beekman

On Thu, May 28, 2020 at 07:16:35PM +0200, Borislav Petkov wrote:
> Lemme reply to all mails with one. :-)
> 
> I think Sean almost had it:
> 
> >  sgx_alloc_epc_section -> sgx_map_epc_section
> >  sgx_free_epc_section  -> sgx_unmap_epc_section
> 
> Or even
> 
>   sgx_setup_epc_section()
>   sgx_free_epc_section()

I like these. Lets lock in.

> And except those last two. Those are allocating a page from the EPC
> sections so I'd call them:
> 
> sgx_try_alloc_page    -> sgx_alloc_epc_page_section
> __sgx_try_alloc_page  -> __sgx_alloc_epc_page_section
> 
> former doing the loop, latter doing the per-section list games.

sgx_alloc_epc_page_section() is a bit nasty and long name to use for
grabbing a page. And even the documentation spoke about grabbing before
this naming discussion. I think it is a great description what is going
on.  Everytime I talk about the subject I talk about grabbing.

Lets just say that your suggestion, I could not use in a conference
talk as a verb when I describe what is going on. That function
signature does not fit to my mouth :-) I would talk about
grabbing a page.

This how I refactored yesterday (is in my GIT tree already):

/**
 * sgx_grab_page() - Grab a free EPC page
 * @owner:	the owner of the EPC page
 * @reclaim:	reclaim pages if necessary
 *
 * Iterate through EPC sections and borrow a free EPC page to the caller. When a
 * page is no longer needed it must be released with sgx_free_page(). If
 * @reclaim is set to true, directly reclaim pages when we are out of pages. No
 * mm's can be locked when @reclaim is set to true.
 *
 * Finally, wake up ksgxswapd when the number of pages goes below the watermark
 * before returning back to the caller.
 *
 * Return:
 *   an EPC page,
 *   -errno on error
 */

I also rewrote the kdoc.

I do agree that sgx_try_grab_page() should be renamed as __sgx_grab_page().

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
  2020-05-28 19:07                 ` Jarkko Sakkinen
@ 2020-05-28 19:59                   ` Sean Christopherson
  2020-05-29  3:28                     ` Jarkko Sakkinen
  0 siblings, 1 reply; 76+ messages in thread
From: Sean Christopherson @ 2020-05-28 19:59 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: Borislav Petkov, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Jethro Beekman

On Thu, May 28, 2020 at 10:07:18PM +0300, Jarkko Sakkinen wrote:
> On Thu, May 28, 2020 at 07:16:35PM +0200, Borislav Petkov wrote:
> > Lemme reply to all mails with one. :-)
> > And except those last two. Those are allocating a page from the EPC
> > sections so I'd call them:
> > 
> > sgx_try_alloc_page    -> sgx_alloc_epc_page_section
> > __sgx_try_alloc_page  -> __sgx_alloc_epc_page_section
> > 
> > former doing the loop, latter doing the per-section list games.
> 
> sgx_alloc_epc_page_section() is a bit nasty and long name to use for
> grabbing a page. And even the documentation spoke about grabbing before
> this naming discussion. I think it is a great description what is going
> on.  Everytime I talk about the subject I talk about grabbing.
> 
> Lets just say that your suggestion, I could not use in a conference
> talk as a verb when I describe what is going on. That function
> signature does not fit to my mouth :-) I would talk about
> grabbing a page.

"allocate an EPC page from the specified section"

It also works if/when we add NUMA awareness, e.g. sgx_alloc_epc_page_node()
means "allocate an EPC page from the specified node".  Note that I'm not
inventing these from scratch, simply stealing them from alloc_pages() and
alloc_pages_node().  The section thing is unique to SGX, but the underlying
concept is the same.

> This how I refactored yesterday (is in my GIT tree already):
> 
> /**
>  * sgx_grab_page() - Grab a free EPC page
>  * @owner:	the owner of the EPC page
>  * @reclaim:	reclaim pages if necessary
>  *
>  * Iterate through EPC sections and borrow a free EPC page to the caller. When a
>  * page is no longer needed it must be released with sgx_free_page(). If
>  * @reclaim is set to true, directly reclaim pages when we are out of pages. No
>  * mm's can be locked when @reclaim is set to true.
>  *
>  * Finally, wake up ksgxswapd when the number of pages goes below the watermark
>  * before returning back to the caller.
>  *
>  * Return:
>  *   an EPC page,
>  *   -errno on error
>  */
> 
> I also rewrote the kdoc.
> 
> I do agree that sgx_try_grab_page() should be renamed as __sgx_grab_page().

FWIW, I really, really dislike "grab".  The nomenclature for normal memory
and pages uses "alloc" when taking a page off a free list, and "grab" when
elevating the refcount.  I don't understand the motivation for diverging
from that.  SGX is weird enough as is, using names that don't align with
exist norms will only serve to further obfuscate the code.

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
  2020-05-28 19:59                   ` Sean Christopherson
@ 2020-05-29  3:28                     ` Jarkko Sakkinen
  2020-05-29  3:37                       ` Sean Christopherson
  2020-05-29  3:38                       ` Jarkko Sakkinen
  0 siblings, 2 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-29  3:28 UTC (permalink / raw)
  To: Sean Christopherson
  Cc: Borislav Petkov, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Jethro Beekman

On Thu, May 28, 2020 at 12:59:17PM -0700, Sean Christopherson wrote:
> On Thu, May 28, 2020 at 10:07:18PM +0300, Jarkko Sakkinen wrote:
> > On Thu, May 28, 2020 at 07:16:35PM +0200, Borislav Petkov wrote:
> > > Lemme reply to all mails with one. :-)
> > > And except those last two. Those are allocating a page from the EPC
> > > sections so I'd call them:
> > > 
> > > sgx_try_alloc_page    -> sgx_alloc_epc_page_section
> > > __sgx_try_alloc_page  -> __sgx_alloc_epc_page_section
> > > 
> > > former doing the loop, latter doing the per-section list games.
> > 
> > sgx_alloc_epc_page_section() is a bit nasty and long name to use for
> > grabbing a page. And even the documentation spoke about grabbing before
> > this naming discussion. I think it is a great description what is going
> > on.  Everytime I talk about the subject I talk about grabbing.
> > Lets just say that your suggestion, I could not use in a conference
> > talk as a verb when I describe what is going on. That function
> > signature does not fit to my mouth :-) I would talk about
> > grabbing a page.
> 
> "allocate an EPC page from the specified section"
> 
> It also works if/when we add NUMA awareness, e.g. sgx_alloc_epc_page_node()
> means "allocate an EPC page from the specified node".  Note that I'm not
> inventing these from scratch, simply stealing them from alloc_pages() and
> alloc_pages_node().  The section thing is unique to SGX, but the underlying
> concept is the same.

Then it should be sgx_alloc_epc_page_from_section() if you go with that.
Otherwise it is mixes too much with the section. I did read these mails
first quickly and first thought that functions were doing something with
sgx_epc_section and not with pages.

Only with a deeper look that it's the name for allocating a page.

I think both names are waste of screen estate. Too long.

> >  * sgx_grab_page() - Grab a free EPC page
> >  * @owner:	the owner of the EPC page
> >  * @reclaim:	reclaim pages if necessary
> >  *
> >  * Iterate through EPC sections and borrow a free EPC page to the caller. When a
> >  * page is no longer needed it must be released with sgx_free_page(). If
> >  * @reclaim is set to true, directly reclaim pages when we are out of pages. No
> >  * mm's can be locked when @reclaim is set to true.
> >  *
> >  * Finally, wake up ksgxswapd when the number of pages goes below the watermark
> >  * before returning back to the caller.
> >  *
> >  * Return:
> >  *   an EPC page,
> >  *   -errno on error
> >  */
> > 
> > I also rewrote the kdoc.
> > 
> > I do agree that sgx_try_grab_page() should be renamed as __sgx_grab_page().
> 
> FWIW, I really, really dislike "grab".  The nomenclature for normal memory
> and pages uses "alloc" when taking a page off a free list, and "grab" when
> elevating the refcount.  I don't understand the motivation for diverging
> from that.  SGX is weird enough as is, using names that don't align with
> exist norms will only serve to further obfuscate the code.

OK, what would be a better name then? The semantics are not standard
memory allocation semantics in the first place. And kdoc in v30 speaks
about grabbing.

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
  2020-05-29  3:28                     ` Jarkko Sakkinen
@ 2020-05-29  3:37                       ` Sean Christopherson
  2020-05-29  5:07                         ` Jarkko Sakkinen
  2020-05-29  8:12                         ` Jarkko Sakkinen
  2020-05-29  3:38                       ` Jarkko Sakkinen
  1 sibling, 2 replies; 76+ messages in thread
From: Sean Christopherson @ 2020-05-29  3:37 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: Borislav Petkov, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Jethro Beekman

On Fri, May 29, 2020 at 06:28:16AM +0300, Jarkko Sakkinen wrote:
> On Thu, May 28, 2020 at 12:59:17PM -0700, Sean Christopherson wrote:
> > On Thu, May 28, 2020 at 10:07:18PM +0300, Jarkko Sakkinen wrote:
> > >  * sgx_grab_page() - Grab a free EPC page
> > >  * @owner:	the owner of the EPC page
> > >  * @reclaim:	reclaim pages if necessary
> > >  *
> > >  * Iterate through EPC sections and borrow a free EPC page to the caller. When a
> > >  * page is no longer needed it must be released with sgx_free_page(). If
> > >  * @reclaim is set to true, directly reclaim pages when we are out of pages. No
> > >  * mm's can be locked when @reclaim is set to true.
> > >  *
> > >  * Finally, wake up ksgxswapd when the number of pages goes below the watermark
> > >  * before returning back to the caller.
> > >  *
> > >  * Return:
> > >  *   an EPC page,
> > >  *   -errno on error
> > >  */
> > > 
> > > I also rewrote the kdoc.
> > > 
> > > I do agree that sgx_try_grab_page() should be renamed as __sgx_grab_page().
> > 
> > FWIW, I really, really dislike "grab".  The nomenclature for normal memory
> > and pages uses "alloc" when taking a page off a free list, and "grab" when
> > elevating the refcount.  I don't understand the motivation for diverging
> > from that.  SGX is weird enough as is, using names that don't align with
> > exist norms will only serve to further obfuscate the code.
> 
> OK, what would be a better name then? The semantics are not standard
> memory allocation semantics in the first place. And kdoc in v30 speaks
> about grabbing.

In what way are they not standard allocation semantics?  sgx_alloc_page()
is an API to allocate (EPC) memory on-demand, sgx_free_page() is its partner
to free that memory when it is no longer needed.  There are many different
ways to manage and allocate memory, but the basic premise is the same for
all and no different than what we're doing.

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
  2020-05-29  3:28                     ` Jarkko Sakkinen
  2020-05-29  3:37                       ` Sean Christopherson
@ 2020-05-29  3:38                       ` Jarkko Sakkinen
  1 sibling, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-29  3:38 UTC (permalink / raw)
  To: Sean Christopherson
  Cc: Borislav Petkov, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Jethro Beekman

On Fri, May 29, 2020 at 06:28:28AM +0300, Jarkko Sakkinen wrote:
> On Thu, May 28, 2020 at 12:59:17PM -0700, Sean Christopherson wrote:
> > On Thu, May 28, 2020 at 10:07:18PM +0300, Jarkko Sakkinen wrote:
> > > On Thu, May 28, 2020 at 07:16:35PM +0200, Borislav Petkov wrote:
> > > > Lemme reply to all mails with one. :-)
> > > > And except those last two. Those are allocating a page from the EPC
> > > > sections so I'd call them:
> > > > 
> > > > sgx_try_alloc_page    -> sgx_alloc_epc_page_section
> > > > __sgx_try_alloc_page  -> __sgx_alloc_epc_page_section
> > > > 
> > > > former doing the loop, latter doing the per-section list games.
> > > 
> > > sgx_alloc_epc_page_section() is a bit nasty and long name to use for
> > > grabbing a page. And even the documentation spoke about grabbing before
> > > this naming discussion. I think it is a great description what is going
> > > on.  Everytime I talk about the subject I talk about grabbing.
> > > Lets just say that your suggestion, I could not use in a conference
> > > talk as a verb when I describe what is going on. That function > > > signature does not fit to my mouth :-) I would talk about
> > > grabbing a page.
> > 
> > "allocate an EPC page from the specified section"
> > 
> > It also works if/when we add NUMA awareness, e.g. sgx_alloc_epc_page_node()
> > means "allocate an EPC page from the specified node".  Note that I'm not
> > inventing these from scratch, simply stealing them from alloc_pages() and
> > alloc_pages_node().  The section thing is unique to SGX, but the underlying
> > concept is the same.
> 
> Then it should be sgx_alloc_epc_page_from_section() if you go with that.
> Otherwise it is mixes too much with the section. I did read these mails
> first quickly and first thought that functions were doing something with
> sgx_epc_section and not with pages.
> 
> Only with a deeper look that it's the name for allocating a page.
> 
> I think both names are waste of screen estate. Too long.
> 
> > >  * sgx_grab_page() - Grab a free EPC page
> > >  * @owner:	the owner of the EPC page
> > >  * @reclaim:	reclaim pages if necessary
> > >  *
> > >  * Iterate through EPC sections and borrow a free EPC page to the caller. When a
> > >  * page is no longer needed it must be released with sgx_free_page(). If
> > >  * @reclaim is set to true, directly reclaim pages when we are out of pages. No
> > >  * mm's can be locked when @reclaim is set to true.
> > >  *
> > >  * Finally, wake up ksgxswapd when the number of pages goes below the watermark
> > >  * before returning back to the caller.
> > >  *
> > >  * Return:
> > >  *   an EPC page,
> > >  *   -errno on error
> > >  */
> > > 
> > > I also rewrote the kdoc.
> > > 
> > > I do agree that sgx_try_grab_page() should be renamed as __sgx_grab_page().
> > 
> > FWIW, I really, really dislike "grab".  The nomenclature for normal memory
> > and pages uses "alloc" when taking a page off a free list, and "grab" when
> > elevating the refcount.  I don't understand the motivation for diverging
> > from that.  SGX is weird enough as is, using names that don't align with
> > exist norms will only serve to further obfuscate the code.
> 
> OK, what would be a better name then? The semantics are not standard
> memory allocation semantics in the first place. And kdoc in v30 speaks
> about grabbing.

I can live with sgx_alloc_epc_page() or sgx_alloc_epc_page_from_section()
although I'd prefer the shorter form.

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
  2020-05-29  3:37                       ` Sean Christopherson
@ 2020-05-29  5:07                         ` Jarkko Sakkinen
  2020-05-29  8:12                         ` Jarkko Sakkinen
  1 sibling, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-29  5:07 UTC (permalink / raw)
  To: Sean Christopherson
  Cc: Borislav Petkov, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Jethro Beekman

On Thu, May 28, 2020 at 08:37:16PM -0700, Sean Christopherson wrote:
> On Fri, May 29, 2020 at 06:28:16AM +0300, Jarkko Sakkinen wrote:
> > On Thu, May 28, 2020 at 12:59:17PM -0700, Sean Christopherson wrote:
> > > On Thu, May 28, 2020 at 10:07:18PM +0300, Jarkko Sakkinen wrote:
> > > >  * sgx_grab_page() - Grab a free EPC page
> > > >  * @owner:	the owner of the EPC page
> > > >  * @reclaim:	reclaim pages if necessary
> > > >  *
> > > >  * Iterate through EPC sections and borrow a free EPC page to the caller. When a
> > > >  * page is no longer needed it must be released with sgx_free_page(). If
> > > >  * @reclaim is set to true, directly reclaim pages when we are out of pages. No
> > > >  * mm's can be locked when @reclaim is set to true.
> > > >  *
> > > >  * Finally, wake up ksgxswapd when the number of pages goes below the watermark
> > > >  * before returning back to the caller.
> > > >  *
> > > >  * Return:
> > > >  *   an EPC page,
> > > >  *   -errno on error
> > > >  */
> > > > 
> > > > I also rewrote the kdoc.
> > > > 
> > > > I do agree that sgx_try_grab_page() should be renamed as __sgx_grab_page().
> > > 
> > > FWIW, I really, really dislike "grab".  The nomenclature for normal memory
> > > and pages uses "alloc" when taking a page off a free list, and "grab" when
> > > elevating the refcount.  I don't understand the motivation for diverging
> > > from that.  SGX is weird enough as is, using names that don't align with
> > > exist norms will only serve to further obfuscate the code.
> > 
> > OK, what would be a better name then? The semantics are not standard
> > memory allocation semantics in the first place. And kdoc in v30 speaks
> > about grabbing.
> 
> In what way are they not standard allocation semantics?  sgx_alloc_page()
> is an API to allocate (EPC) memory on-demand, sgx_free_page() is its partner
> to free that memory when it is no longer needed.  There are many different
> ways to manage and allocate memory, but the basic premise is the same for
> all and no different than what we're doing.

I'll go with sgx_alloc_epc_page(). It is more precise name.

It's not as precise as sgx_alloc_epc_page_from_section but is a great
compromise between scree estate and clarity of expression :-)

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
  2020-05-29  3:37                       ` Sean Christopherson
  2020-05-29  5:07                         ` Jarkko Sakkinen
@ 2020-05-29  8:12                         ` Jarkko Sakkinen
  2020-05-29  8:13                           ` Jarkko Sakkinen
  1 sibling, 1 reply; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-29  8:12 UTC (permalink / raw)
  To: Sean Christopherson
  Cc: Borislav Petkov, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Jethro Beekman

On Thu, May 28, 2020 at 08:37:16PM -0700, Sean Christopherson wrote:
> On Fri, May 29, 2020 at 06:28:16AM +0300, Jarkko Sakkinen wrote:
> > On Thu, May 28, 2020 at 12:59:17PM -0700, Sean Christopherson wrote:
> > > On Thu, May 28, 2020 at 10:07:18PM +0300, Jarkko Sakkinen wrote:
> > > >  * sgx_grab_page() - Grab a free EPC page
> > > >  * @owner:	the owner of the EPC page
> > > >  * @reclaim:	reclaim pages if necessary
> > > >  *
> > > >  * Iterate through EPC sections and borrow a free EPC page to the caller. When a
> > > >  * page is no longer needed it must be released with sgx_free_page(). If
> > > >  * @reclaim is set to true, directly reclaim pages when we are out of pages. No
> > > >  * mm's can be locked when @reclaim is set to true.
> > > >  *
> > > >  * Finally, wake up ksgxswapd when the number of pages goes below the watermark
> > > >  * before returning back to the caller.
> > > >  *
> > > >  * Return:
> > > >  *   an EPC page,
> > > >  *   -errno on error
> > > >  */
> > > > 
> > > > I also rewrote the kdoc.
> > > > 
> > > > I do agree that sgx_try_grab_page() should be renamed as __sgx_grab_page().
> > > 
> > > FWIW, I really, really dislike "grab".  The nomenclature for normal memory
> > > and pages uses "alloc" when taking a page off a free list, and "grab" when
> > > elevating the refcount.  I don't understand the motivation for diverging
> > > from that.  SGX is weird enough as is, using names that don't align with
> > > exist norms will only serve to further obfuscate the code.
> > 
> > OK, what would be a better name then? The semantics are not standard
> > memory allocation semantics in the first place. And kdoc in v30 speaks
> > about grabbing.
> 
> In what way are they not standard allocation semantics?  sgx_alloc_page()
> is an API to allocate (EPC) memory on-demand, sgx_free_page() is its partner
> to free that memory when it is no longer needed.  There are many different
> ways to manage and allocate memory, but the basic premise is the same for
> all and no different than what we're doing.

I end up to (ignoring unchanged names):

- __sgx_alloc_epc_page_from_section() (static)
- __sgx_alloc_epc_page()
- sgx_alloc_epc_page()
- sgx_setup_epc_section()

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages
  2020-05-29  8:12                         ` Jarkko Sakkinen
@ 2020-05-29  8:13                           ` Jarkko Sakkinen
  0 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-29  8:13 UTC (permalink / raw)
  To: Sean Christopherson
  Cc: Borislav Petkov, linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Jethro Beekman

On Fri, May 29, 2020 at 11:13:09AM +0300, Jarkko Sakkinen wrote:
> On Thu, May 28, 2020 at 08:37:16PM -0700, Sean Christopherson wrote:
> > On Fri, May 29, 2020 at 06:28:16AM +0300, Jarkko Sakkinen wrote:
> > > On Thu, May 28, 2020 at 12:59:17PM -0700, Sean Christopherson wrote:
> > > > On Thu, May 28, 2020 at 10:07:18PM +0300, Jarkko Sakkinen wrote:
> > > > >  * sgx_grab_page() - Grab a free EPC page
> > > > >  * @owner:	the owner of the EPC page
> > > > >  * @reclaim:	reclaim pages if necessary
> > > > >  *
> > > > >  * Iterate through EPC sections and borrow a free EPC page to the caller. When a
> > > > >  * page is no longer needed it must be released with sgx_free_page(). If
> > > > >  * @reclaim is set to true, directly reclaim pages when we are out of pages. No
> > > > >  * mm's can be locked when @reclaim is set to true.
> > > > >  *
> > > > >  * Finally, wake up ksgxswapd when the number of pages goes below the watermark
> > > > >  * before returning back to the caller.
> > > > >  *
> > > > >  * Return:
> > > > >  *   an EPC page,
> > > > >  *   -errno on error
> > > > >  */
> > > > > 
> > > > > I also rewrote the kdoc.
> > > > > 
> > > > > I do agree that sgx_try_grab_page() should be renamed as __sgx_grab_page().
> > > > 
> > > > FWIW, I really, really dislike "grab".  The nomenclature for normal memory
> > > > and pages uses "alloc" when taking a page off a free list, and "grab" when
> > > > elevating the refcount.  I don't understand the motivation for diverging
> > > > from that.  SGX is weird enough as is, using names that don't align with
> > > > exist norms will only serve to further obfuscate the code.
> > > 
> > > OK, what would be a better name then? The semantics are not standard
> > > memory allocation semantics in the first place. And kdoc in v30 speaks
> > > about grabbing.
> > 
> > In what way are they not standard allocation semantics?  sgx_alloc_page()
> > is an API to allocate (EPC) memory on-demand, sgx_free_page() is its partner
> > to free that memory when it is no longer needed.  There are many different
> > ways to manage and allocate memory, but the basic premise is the same for
> > all and no different than what we're doing.
> 
> I end up to (ignoring unchanged names):
> 
> - __sgx_alloc_epc_page_from_section() (static)
> - __sgx_alloc_epc_page()
> - sgx_alloc_epc_page()
> - sgx_setup_epc_section()

OK, also sgx_free_epc_page (not sgx_free_page() as before).

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 09/20] mm: Introduce vm_ops->may_mprotect()
  2020-05-15  0:43 ` [PATCH v30 09/20] mm: Introduce vm_ops->may_mprotect() Jarkko Sakkinen
@ 2020-05-29 12:10   ` Borislav Petkov
  2020-05-29 18:18     ` Jarkko Sakkinen
  2020-05-29 18:28   ` Dave Hansen
  1 sibling, 1 reply; 76+ messages in thread
From: Borislav Petkov @ 2020-05-29 12:10 UTC (permalink / raw)
  To: Jarkko Sakkinen
  Cc: linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	sean.j.christopherson, nhorman, npmccallum, haitao.huang,
	andriy.shevchenko, tglx, kai.svahn, josh, luto, kai.huang,
	rientjes, cedric.xing, puiterwijk, Jethro Beekman

On Fri, May 15, 2020 at 03:43:59AM +0300, Jarkko Sakkinen wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
> 
> Add vm_ops()->may_mprotect() to check additional constrains set by a

"constraints"

> subsystem for a mprotect() call.
> 
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Acked-by: Jethro Beekman <jethro@fortanix.com>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> ---
>  include/linux/mm.h |  2 ++
>  mm/mprotect.c      | 14 +++++++++++---
>  2 files changed, 13 insertions(+), 3 deletions(-)

This needs an ACK from an mm person.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 09/20] mm: Introduce vm_ops->may_mprotect()
  2020-05-29 12:10   ` Borislav Petkov
@ 2020-05-29 18:18     ` Jarkko Sakkinen
  0 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-29 18:18 UTC (permalink / raw)
  To: Borislav Petkov
  Cc: linux-kernel, x86, linux-sgx, akpm, dave.hansen,
	sean.j.christopherson, nhorman, npmccallum, haitao.huang,
	andriy.shevchenko, tglx, kai.svahn, josh, luto, kai.huang,
	rientjes, cedric.xing, puiterwijk, Jethro Beekman

On Fri, May 29, 2020 at 02:10:38PM +0200, Borislav Petkov wrote:
> On Fri, May 15, 2020 at 03:43:59AM +0300, Jarkko Sakkinen wrote:
> > From: Sean Christopherson <sean.j.christopherson@intel.com>
> > 
> > Add vm_ops()->may_mprotect() to check additional constrains set by a
> 
> "constraints"
> 
> > subsystem for a mprotect() call.
> > 
> > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> > Acked-by: Jethro Beekman <jethro@fortanix.com>
> > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> > ---
> >  include/linux/mm.h |  2 ++
> >  mm/mprotect.c      | 14 +++++++++++---
> >  2 files changed, 13 insertions(+), 3 deletions(-)
> 
> This needs an ACK from an mm person.

Good point. I'll add the needed cc's.

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 09/20] mm: Introduce vm_ops->may_mprotect()
  2020-05-15  0:43 ` [PATCH v30 09/20] mm: Introduce vm_ops->may_mprotect() Jarkko Sakkinen
  2020-05-29 12:10   ` Borislav Petkov
@ 2020-05-29 18:28   ` Dave Hansen
  2020-05-31 23:12     ` Jarkko Sakkinen
  1 sibling, 1 reply; 76+ messages in thread
From: Dave Hansen @ 2020-05-29 18:28 UTC (permalink / raw)
  To: Jarkko Sakkinen, linux-kernel, x86, linux-sgx
  Cc: akpm, sean.j.christopherson, nhorman, npmccallum, haitao.huang,
	andriy.shevchenko, tglx, kai.svahn, bp, josh, luto, kai.huang,
	rientjes, cedric.xing, puiterwijk, Jethro Beekman

On 5/14/20 5:43 PM, Jarkko Sakkinen wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
> 
> Add vm_ops()->may_mprotect() to check additional constrains set by a
> subsystem for a mprotect() call.

This changelog needs some more detail about why this is needed.  It
would also be nice to include thought about what else it could get used
for and what subsystems can expect by doing this and what the mm core is
expected to do.




^ permalink raw reply	[flat|nested] 76+ messages in thread

* Re: [PATCH v30 09/20] mm: Introduce vm_ops->may_mprotect()
  2020-05-29 18:28   ` Dave Hansen
@ 2020-05-31 23:12     ` Jarkko Sakkinen
  0 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-31 23:12 UTC (permalink / raw)
  To: Dave Hansen
  Cc: linux-kernel, x86, linux-sgx, akpm, sean.j.christopherson,
	nhorman, npmccallum, haitao.huang, andriy.shevchenko, tglx,
	kai.svahn, bp, josh, luto, kai.huang, rientjes, cedric.xing,
	puiterwijk, Jethro Beekman

On Fri, May 29, 2020 at 11:28:56AM -0700, Dave Hansen wrote:
> On 5/14/20 5:43 PM, Jarkko Sakkinen wrote:
> > From: Sean Christopherson <sean.j.christopherson@intel.com>
> > 
> > Add vm_ops()->may_mprotect() to check additional constrains set by a
> > subsystem for a mprotect() call.
> 
> This changelog needs some more detail about why this is needed.  It
> would also be nice to include thought about what else it could get used
> for and what subsystems can expect by doing this and what the mm core is
> expected to do.

Point taken. I added a description on how it is used.

/Jarkko

^ permalink raw reply	[flat|nested] 76+ messages in thread

* [PATCH] x86/cpu/intel: Add nosgx kernel parameter
  2020-04-21 21:52 [PATCH v29 00/20] Intel SGX foundations Jarkko Sakkinen
@ 2020-05-16  8:53 ` Jarkko Sakkinen
  0 siblings, 0 replies; 76+ messages in thread
From: Jarkko Sakkinen @ 2020-05-16  8:53 UTC (permalink / raw)
  To: linux-kernel, x86, linux-sgx
  Cc: Jarkko Sakkinen, Sean Christopherson, akpm, andriy.shevchenko,
	asapek, bp, cedric.xing, chenalexchen, conradparker, cyhanish,
	dave.hansen, haitao.huang, josh, kai.huang, kai.svahn, kmoy,
	ludloff, luto, nhorman, npmccallum, puiterwijk, rientjes, tglx,
	yaozhangx

Add kernel parameter to disable Intel SGX kernel support.

Tested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 Documentation/admin-guide/kernel-parameters.txt | 2 ++
 arch/x86/kernel/cpu/feat_ctl.c                  | 9 +++++++++
 2 files changed, 11 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 7bc83f3d9bdf..9f7202a54db6 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3268,6 +3268,8 @@
 
 	nosep		[BUGS=X86-32] Disables x86 SYSENTER/SYSEXIT support.
 
+	nosgx		[X86-64,SGX] Disables Intel SGX kernel support.
+
 	nosmp		[SMP] Tells an SMP kernel to act as a UP kernel,
 			and disable the IO APIC.  legacy for "maxcpus=0".
 
diff --git a/arch/x86/kernel/cpu/feat_ctl.c b/arch/x86/kernel/cpu/feat_ctl.c
index c3afcd2e4342..1837df39527f 100644
--- a/arch/x86/kernel/cpu/feat_ctl.c
+++ b/arch/x86/kernel/cpu/feat_ctl.c
@@ -101,6 +101,15 @@ static void clear_sgx_caps(void)
 	setup_clear_cpu_cap(X86_FEATURE_SGX2);
 }
 
+static int __init nosgx(char *str)
+{
+	clear_sgx_caps();
+
+	return 0;
+}
+
+early_param("nosgx", nosgx);
+
 void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
 {
 	bool tboot = tboot_enabled();
-- 
2.25.1


^ permalink raw reply	[flat|nested] 76+ messages in thread

end of thread, back to index

Thread overview: 76+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 01/20] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2020-05-20 12:16   ` Borislav Petkov
2020-05-20 14:00     ` Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 02/20] x86/cpufeatures: x86/msr: Intel SGX Launch Control " Jarkko Sakkinen
2020-05-20 12:23   ` Borislav Petkov
2020-05-20 14:04     ` Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 03/20] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 04/20] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
2020-05-20 18:47   ` Borislav Petkov
2020-05-20 21:04     ` Sean Christopherson
2020-05-22 15:54     ` Jarkko Sakkinen
2020-05-22 16:13       ` Sean Christopherson
2020-05-22 19:50         ` Jarkko Sakkinen
2020-05-25  8:20           ` Borislav Petkov
2020-05-27 19:43             ` Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 05/20] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 06/20] x86/cpu/intel: Detect SGX support Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 07/20] x86/sgx: Enumerate and track EPC sections Jarkko Sakkinen
2020-05-25  9:23   ` Borislav Petkov
2020-05-27  3:56     ` Sean Christopherson
2020-05-27 20:35       ` Borislav Petkov
2020-05-28  7:36         ` Jarkko Sakkinen
2020-05-28  5:25       ` Jarkko Sakkinen
2020-05-28  5:35         ` Jarkko Sakkinen
2020-05-28  6:14           ` Jarkko Sakkinen
2020-05-28  6:16             ` Jarkko Sakkinen
2020-05-28  5:13     ` Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages Jarkko Sakkinen
2020-05-26 12:52   ` Borislav Petkov
2020-05-27  4:21     ` Sean Christopherson
2020-05-27 20:46       ` Borislav Petkov
2020-05-28  0:52         ` Sean Christopherson
2020-05-28  6:51           ` Jarkko Sakkinen
2020-05-28  1:23         ` Jarkko Sakkinen
2020-05-28  1:36           ` Sean Christopherson
2020-05-28  6:52             ` Jarkko Sakkinen
2020-05-28 17:16               ` Borislav Petkov
2020-05-28 17:19                 ` Sean Christopherson
2020-05-28 17:27                   ` Borislav Petkov
2020-05-28 17:34                     ` Sean Christopherson
2020-05-28 19:07                 ` Jarkko Sakkinen
2020-05-28 19:59                   ` Sean Christopherson
2020-05-29  3:28                     ` Jarkko Sakkinen
2020-05-29  3:37                       ` Sean Christopherson
2020-05-29  5:07                         ` Jarkko Sakkinen
2020-05-29  8:12                         ` Jarkko Sakkinen
2020-05-29  8:13                           ` Jarkko Sakkinen
2020-05-29  3:38                       ` Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 09/20] mm: Introduce vm_ops->may_mprotect() Jarkko Sakkinen
2020-05-29 12:10   ` Borislav Petkov
2020-05-29 18:18     ` Jarkko Sakkinen
2020-05-29 18:28   ` Dave Hansen
2020-05-31 23:12     ` Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 10/20] x86/sgx: Linux Enclave Driver Jarkko Sakkinen
2020-05-21 19:12   ` Sean Christopherson
2020-05-22 19:26     ` Jarkko Sakkinen
2020-05-22 19:39     ` Jarkko Sakkinen
2020-05-22  3:33   ` Sean Christopherson
2020-05-15  0:44 ` [PATCH v30 11/20] x86/sgx: Add provisioning Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 12/20] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2020-05-22  6:58   ` Sean Christopherson
2020-05-22 19:57     ` Jarkko Sakkinen
2020-05-22 21:52       ` Sean Christopherson
2020-05-22  7:15   ` Sean Christopherson
2020-05-22 19:47     ` Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 13/20] x86/sgx: ptrace() support for the SGX driver Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 14/20] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 15/20] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 16/20] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 17/20] x86/vdso: Implement a vDSO for Intel SGX enclave call Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 18/20] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 19/20] docs: x86/sgx: Document SGX micro architecture and kernel internals Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 20/20] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2020-05-16  8:57 ` [PATCH] x86/cpu/intel: Add nosgx kernel parameter Jarkko Sakkinen
  -- strict thread matches above, loose matches on Subject: below --
2020-04-21 21:52 [PATCH v29 00/20] Intel SGX foundations Jarkko Sakkinen
2020-05-16  8:53 ` [PATCH] x86/cpu/intel: Add nosgx kernel parameter Jarkko Sakkinen

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