From: Jarkko Sakkinen <jarkko@kernel.org>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: x86@kernel.org, linux-sgx@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org, linux-mm@kvack.org,
Andrew Morton <akpm@linux-foundation.org>,
Matthew Wilcox <willy@infradead.org>,
Jethro Beekman <jethro@fortanix.com>,
Haitao Huang <haitao.huang@linux.intel.com>,
Chunyang Hui <sanqian.hcy@antfin.com>,
Jordan Hand <jorhand@linux.microsoft.com>,
Nathaniel McCallum <npmccallum@redhat.com>,
Seth Moore <sethmo@google.com>,
Darren Kenny <darren.kenny@oracle.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
Suresh Siddha <suresh.b.siddha@intel.com>,
andriy.shevchenko@linux.intel.com, asapek@google.com,
bp@alien8.de, cedric.xing@intel.com, chenalexchen@google.com,
conradparker@google.com, cyhanish@google.com,
dave.hansen@intel.com, haitao.huang@intel.com,
kai.huang@intel.com, kai.svahn@intel.com, kmoy@google.com,
ludloff@google.com, luto@kernel.org, nhorman@redhat.com,
puiterwijk@redhat.com, rientjes@google.com, tglx@linutronix.de,
yaozhangx@google.com, mikko.ylinen@intel.com
Subject: Re: [PATCH v40 11/24] x86/sgx: Add SGX misc driver interface
Date: Thu, 5 Nov 2020 03:10:43 +0200 [thread overview]
Message-ID: <20201105011043.GA700495@kernel.org> (raw)
In-Reply-To: <20201104145430.300542-12-jarkko.sakkinen@linux.intel.com>
Noticed couple of minor glitches.
On Wed, Nov 04, 2020 at 04:54:17PM +0200, Jarkko Sakkinen wrote:
> +int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start,
> + unsigned long end, unsigned long vm_flags)
> +{
> + unsigned long vm_prot_bits = vm_flags & (VM_READ | VM_WRITE | VM_EXEC);
> + struct sgx_encl_page *page;
> + unsigned long count = 0;
> + int ret = 0;
> +
> + XA_STATE(xas, &encl->page_array, PFN_DOWN(start));
> +
> + /*
> + * Disallow READ_IMPLIES_EXEC tasks as their VMA permissions might
> + * conflict with the enclave page permissions.
> + */
> + if (current->personality & READ_IMPLIES_EXEC)
> + return -EACCES;
> +
> + mutex_lock(&encl->lock);
> + xas_lock(&xas);
> + xas_for_each(&xas, page, PFN_DOWN(end - 1)) {
> + if (!page)
> + break;
A redundant check, can be removed.
> +
> + if (~page->vm_max_prot_bits & vm_prot_bits) {
> + ret = -EACCES;
> + break;
> + }
> +
> + /* Reschedule on every XA_CHECK_SCHED iteration. */
> + if (!(++count % XA_CHECK_SCHED)) {
> + xas_pause(&xas);
> + xas_unlock(&xas);
> + mutex_unlock(&encl->lock);
> +
> + cond_resched();
> +
> + mutex_lock(&encl->lock);
> + xas_lock(&xas);
> + }
> + }
> + xas_unlock(&xas);
> + mutex_unlock(&encl->lock);
> +
> + return ret;
> +}
> +
> +static int sgx_vma_mprotect(struct vm_area_struct *vma,
> + struct vm_area_struct **pprev, unsigned long start,
> + unsigned long end, unsigned long newflags)
> +{
> + int ret;
> +
> + ret = sgx_encl_may_map(vma->vm_private_data, start, end, newflags);
> + if (ret)
> + return ret;
> +
> + return mprotect_fixup(vma, pprev, start, end, newflags);
> +}
> +
> +const struct vm_operations_struct sgx_vm_ops = {
> + .fault = sgx_vma_fault,
> + .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;
> +}
Since v20 there has been 1:1 assocition between enclaves and files.
In other words, this can never return -ENOENT.
With this reduction the function turns into:
int sgx_encl_find(struct mm_struct *mm, unsigned long addr,
struct vm_area_struct **vma)
{
struct vm_area_struct *result;
result = find_vma(mm, addr);
if (!result || result->vm_ops != &sgx_vm_ops || addr < result->vm_start)
return -EINVAL;
*vma = result;
return 0;
}
There are only two call sites:
1. sgx_encl_test_and_clear_young()
2. sgx_reclaimer_block()
I.e. would not be a big trouble to tune the signature a bit:
struct vm_area_struct *sgx_encl_find_vma(struct mm_struct *mm, unsigned long addr)
{
struct vm_area_struct *result;
result = find_vma(mm, addr);
if (!result || result->vm_ops != &sgx_vm_ops || addr < result->vm_start)
return NULL;
return result;
}
There is a function called sgx_encl_find_mm(), which is *unrelated* to
this function and has only one call sites. Its flow is very linear. In
order to avoid confusion, I'd open code that into sgx_encl_mm_add().
/Jarkko
next prev parent reply other threads:[~2020-11-05 1:10 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-04 14:54 [PATCH v40 00/24] Intel SGX foundations Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 01/24] x86/sgx: Add SGX architectural data structures Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 02/24] x86/sgx: Add wrappers for ENCLS functions Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 03/24] x86/sgx: Initialize metadata for Enclave Page Cache (EPC) sections Jarkko Sakkinen
2020-11-04 18:21 ` Borislav Petkov
2020-11-04 19:04 ` Jarkko Sakkinen
2020-11-04 19:09 ` Jarkko Sakkinen
2020-11-04 19:12 ` Borislav Petkov
2020-11-04 14:54 ` [PATCH v40 04/24] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 05/24] x86/cpufeatures: x86/msr: Add Intel SGX Launch Control " Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 06/24] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 07/24] x86/cpu/intel: Detect SGX support Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 08/24] x86/cpu/intel: Add nosgx kernel parameter Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 09/24] x86/sgx: Add SGX page allocator functions Jarkko Sakkinen
2020-11-05 15:08 ` Borislav Petkov
2020-11-04 14:54 ` [PATCH v40 10/24] mm: Add 'mprotect' hook to struct vm_operations_struct Jarkko Sakkinen
2020-11-05 16:04 ` Borislav Petkov
2020-11-05 17:33 ` Dave Hansen
2020-11-06 10:04 ` Mel Gorman
2020-11-06 16:51 ` Jarkko Sakkinen
2020-11-06 20:37 ` Borislav Petkov
2020-11-06 22:04 ` Jarkko Sakkinen
2020-11-06 22:31 ` Borislav Petkov
2020-11-06 17:43 ` Dr. Greg
2020-11-06 17:54 ` Dave Hansen
2020-11-07 15:09 ` Dr. Greg
2020-11-07 19:16 ` Dave Hansen
2020-11-12 20:58 ` Dr. Greg
2020-11-12 21:31 ` Dave Hansen
2020-11-12 22:41 ` Andy Lutomirski
2020-11-16 18:00 ` Dr. Greg
2020-11-19 1:39 ` Haitao Huang
2020-11-20 17:31 ` Dr. Greg
2020-11-15 18:59 ` Dr. Greg
2020-11-06 21:13 ` Matthew Wilcox
2020-11-06 21:23 ` Dave Hansen
2020-11-07 15:27 ` Dr. Greg
2020-11-04 14:54 ` [PATCH v40 11/24] x86/sgx: Add SGX misc driver interface Jarkko Sakkinen
2020-11-05 1:10 ` Jarkko Sakkinen [this message]
2020-11-05 1:16 ` Jarkko Sakkinen
2020-11-05 16:05 ` Borislav Petkov
2020-11-05 17:57 ` Jarkko Sakkinen
2020-11-05 18:10 ` Borislav Petkov
2020-11-06 16:07 ` Jarkko Sakkinen
2020-11-06 17:09 ` Borislav Petkov
2020-11-06 22:01 ` Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 12/24] x86/sgx: Add SGX_IOC_ENCLAVE_CREATE Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 13/24] x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 14/24] x86/sgx: Add SGX_IOC_ENCLAVE_INIT Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 15/24] x86/sgx: Add SGX_IOC_ENCLAVE_PROVISION Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 16/24] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 17/24] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 18/24] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 19/24] x86/vdso: Implement a vDSO for Intel SGX enclave call Jarkko Sakkinen
2020-11-08 18:24 ` Jethro Beekman
2020-11-08 20:08 ` Jethro Beekman
2020-11-08 20:26 ` Dave Hansen
2020-11-08 20:20 ` Jethro Beekman
2020-11-08 20:30 ` Dave Hansen
2020-11-04 14:54 ` [PATCH v40 20/24] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 21/24] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 22/24] x86/sgx: Add ptrace() support for the SGX driver Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 23/24] docs: x86/sgx: Document SGX kernel architecture Jarkko Sakkinen
2020-11-04 14:54 ` [PATCH v40 24/24] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2020-11-08 20:48 ` [PATCH v40 00/24] Intel SGX foundations Jethro Beekman
[not found] ` <20201108035630.11540-1-hdanton@sina.com>
2020-11-09 19:59 ` [PATCH v40 21/24] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2020-11-21 15:12 ` [PATCH v40 00/24] Intel SGX foundations Dr. Greg
2020-11-21 16:25 ` Dave Hansen
2020-11-24 10:55 ` Dr. Greg
2020-11-24 17:49 ` Andy Lutomirski
2020-11-21 18:36 ` Andy Lutomirski
2020-11-24 18:40 ` Dr. Greg
2020-11-24 21:57 ` Andy Lutomirski
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