From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: linux-sgx@vger.kernel.org, Dave Hansen <dave.hansen@intel.com>,
Cedric Xing <cedric.xing@intel.com>,
Andy Lutomirski <luto@kernel.org>,
Jethro Beekman <jethro@fortanix.com>,
"Dr . Greg Wettstein" <greg@enjellic.com>
Subject: [PATCH 5/7] x86/sgx: Add flag to zero added region instead of copying from source
Date: Wed, 5 Jun 2019 12:48:43 -0700 [thread overview]
Message-ID: <20190605194845.926-6-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20190605194845.926-1-sean.j.christopherson@intel.com>
For some enclaves, e.g. an enclave with a small code footprint and a
large working set, the vast majority of pages added to the enclave are
zero pages. Introduce a flag to denote such zero pages. The major
benefit of the flag will be realized in a future patch to use Linux's
actual zero page as the source, as opposed to explicitly zeroing the
enclave's backing memory.
Use bit 8 for the SGX_ZERO_REGION flag to avoid an anticipated conflict
with passing PROT_{READ,WRITE,EXEC} in bits 2:0, and to leave room in
case there is a need for additional protection related bits.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/include/uapi/asm/sgx.h | 5 +++++
arch/x86/kernel/cpu/sgx/driver/ioctl.c | 15 ++++++++++++---
2 files changed, 17 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/uapi/asm/sgx.h b/arch/x86/include/uapi/asm/sgx.h
index 30d114f6b3bd..18204722f238 100644
--- a/arch/x86/include/uapi/asm/sgx.h
+++ b/arch/x86/include/uapi/asm/sgx.h
@@ -31,6 +31,9 @@ struct sgx_enclave_create {
__u64 src;
};
+/* Zero an added region instead of copying data from a source page. */
+#define SGX_ZERO_REGION 0x100
+
/**
* struct sgx_enclave_add_region - parameter structure for the
* %SGX_IOC_ENCLAVE_ADD_REGION ioctl
@@ -38,6 +41,7 @@ struct sgx_enclave_create {
* @src: start address for the pages' data
* @size: size of region, in bytes
* @secinfo: address of the SECINFO data (common to the entire region)
+ * @flags: miscellaneous flags
* @mrmask: bitmask of 256 byte chunks to measure (applied per 4k page)
*/
struct sgx_enclave_add_region {
@@ -45,6 +49,7 @@ struct sgx_enclave_add_region {
__u64 src;
__u64 size;
__u64 secinfo;
+ __u32 flags;
__u16 mrmask;
} __attribute__((__packed__));
diff --git a/arch/x86/kernel/cpu/sgx/driver/ioctl.c b/arch/x86/kernel/cpu/sgx/driver/ioctl.c
index b69350696b87..c35264ea0c93 100644
--- a/arch/x86/kernel/cpu/sgx/driver/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/driver/ioctl.c
@@ -459,6 +459,9 @@ static int sgx_validate_tcs(struct sgx_encl *encl, struct sgx_tcs *tcs)
{
int i;
+ if (!tcs)
+ return -EINVAL;
+
if (tcs->flags & SGX_TCS_RESERVED_MASK)
return -EINVAL;
@@ -510,7 +513,10 @@ static int sgx_encl_queue_page(struct sgx_encl *encl,
}
backing_ptr = kmap(backing);
- memcpy(backing_ptr, data, PAGE_SIZE);
+ if (data)
+ memcpy(backing_ptr, data, PAGE_SIZE);
+ else
+ memset(backing_ptr, 0, PAGE_SIZE);
kunmap(backing);
if (page_type == SGX_SECINFO_TCS)
encl_page->desc |= SGX_ENCL_PAGE_TCS;
@@ -576,12 +582,15 @@ static int __sgx_encl_add_page(struct sgx_encl *encl, unsigned long addr,
static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long addr,
unsigned long src, struct sgx_secinfo *secinfo,
- unsigned int mrmask)
+ unsigned int mrmask, unsigned long flags)
{
struct page *data_page;
void *data;
int ret;
+ if (flags & SGX_ZERO_REGION)
+ return __sgx_encl_add_page(encl, addr, NULL, secinfo, mrmask);
+
data_page = alloc_page(GFP_HIGHUSER);
if (!data_page)
return -ENOMEM;
@@ -658,7 +667,7 @@ static long sgx_ioc_enclave_add_region(struct file *filep, void __user *arg)
cond_resched();
ret = sgx_encl_add_page(encl, region.addr + i, region.src + i,
- &secinfo, region.mrmask);
+ &secinfo, region.mrmask, region.flags);
if (ret)
break;
}
--
2.21.0
next prev parent reply other threads:[~2019-06-05 19:49 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-05 19:48 [PATCH 0/7] x86/sgx: Clean up and enhance add pages ioctl Sean Christopherson
2019-06-05 19:48 ` [PATCH 1/7] x86/sgx: Remove dead code to handle non-existent IOR ioctl Sean Christopherson
2019-06-05 19:48 ` [PATCH 2/7] x86/sgx: Remove unnecessary @cmd parameter from ioctl helpers Sean Christopherson
2019-06-05 19:48 ` [PATCH 3/7] x86/sgx: Let ioctl helpers do copy to/from user Sean Christopherson
2019-06-05 19:48 ` [PATCH 4/7] x86/sgx: Allow userspace to add multiple pages in single ioctl() Sean Christopherson
2019-06-06 15:47 ` Jarkko Sakkinen
2019-06-13 0:43 ` Jethro Beekman
2019-06-13 16:51 ` Sean Christopherson
2019-06-13 19:05 ` Andy Lutomirski
2019-06-13 19:15 ` Sean Christopherson
2019-06-13 19:45 ` Xing, Cedric
2019-06-05 19:48 ` Sean Christopherson [this message]
2019-06-06 17:20 ` [PATCH 5/7] x86/sgx: Add flag to zero added region instead of copying from source Andy Lutomirski
2019-06-06 17:32 ` Sean Christopherson
2019-06-07 19:32 ` Andy Lutomirski
2019-06-10 17:06 ` Jarkko Sakkinen
2019-06-10 18:09 ` Xing, Cedric
2019-06-10 18:41 ` Sean Christopherson
2019-06-10 18:53 ` Sean Christopherson
2019-06-13 0:38 ` Jethro Beekman
2019-06-13 13:46 ` Sean Christopherson
2019-06-13 16:16 ` Andy Lutomirski
2019-06-13 16:54 ` Sean Christopherson
2019-06-05 19:48 ` [PATCH 6/7] x86/sgx: Use the actual zero page as the source when adding zero pages Sean Christopherson
2019-06-05 19:48 ` [PATCH 7/7] x86/sgx: Add a reserved field to sgx_enclave_add_region to drop 'packed' Sean Christopherson
2019-06-05 19:59 ` Dave Hansen
2019-06-05 20:00 ` Andy Lutomirski
2019-06-12 15:14 ` Jarkko Sakkinen
2019-06-12 15:23 ` Sean Christopherson
2019-06-13 0:44 ` Jethro Beekman
2019-06-13 15:38 ` Jarkko Sakkinen
2019-06-12 15:16 ` [PATCH 0/7] x86/sgx: Clean up and enhance add pages ioctl Jarkko Sakkinen
2019-06-12 18:14 ` Jarkko Sakkinen
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