From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: linux-sgx@vger.kernel.org
Subject: [PATCH for_v23 v3 04/12] x86/sgx: Drop mmap_sem before EEXTENDing an enclave page
Date: Wed, 16 Oct 2019 11:37:37 -0700 [thread overview]
Message-ID: <20191016183745.8226-5-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20191016183745.8226-1-sean.j.christopherson@intel.com>
Drop mmap_sem, which needs to be held for read across EADD, prior to
doing EEXTEND on the newly added page to avoid holding mmap_sem for an
extended duration. EEXTEND doesn't access user pages and holding
encl->lock without mmap_sem is perfectly ok, while EEXTEND is a _slow_
operation, to the point where it operates on 256-byte chunks
instead of 4k pages to maintain a reasonable latency for a single
instruction.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kernel/cpu/sgx/ioctl.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index 4169ff3c81d8..7be3fdc846d7 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -409,11 +409,15 @@ static int sgx_encl_add_page(struct sgx_encl *encl,
*/
ret = radix_tree_insert(&encl->page_tree, PFN_DOWN(encl_page->desc),
encl_page);
- if (ret)
+ if (ret) {
+ up_read(¤t->mm->mmap_sem);
goto err_out_unlock;
+ }
ret = __sgx_encl_add_page(encl, encl_page, epc_page, secinfo,
addp->src);
+ up_read(¤t->mm->mmap_sem);
+
if (ret)
goto err_out;
@@ -433,7 +437,6 @@ static int sgx_encl_add_page(struct sgx_encl *encl,
sgx_mark_page_reclaimable(encl_page->epc_page);
mutex_unlock(&encl->lock);
- up_read(¤t->mm->mmap_sem);
return ret;
err_out:
@@ -443,7 +446,6 @@ static int sgx_encl_add_page(struct sgx_encl *encl,
err_out_unlock:
sgx_encl_shrink(encl, va_page);
mutex_unlock(&encl->lock);
- up_read(¤t->mm->mmap_sem);
err_out_free:
sgx_free_page(epc_page);
--
2.22.0
next prev parent reply other threads:[~2019-10-16 18:37 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-16 18:37 [PATCH for_v23 v3 00/12] x86/sgx: Bug fixes for v23 Sean Christopherson
2019-10-16 18:37 ` [PATCH for_v23 v3 01/12] x86/sgx: Pass EADD the kernel's virtual address for the source page Sean Christopherson
2019-10-18 9:57 ` Jarkko Sakkinen
2019-10-22 3:22 ` Sean Christopherson
2019-10-23 11:57 ` Jarkko Sakkinen
2019-10-16 18:37 ` [PATCH for_v23 v3 02/12] x86/sgx: Check the validity of the source page address for EADD Sean Christopherson
2019-10-16 18:37 ` [PATCH for_v23 v3 03/12] x86/sgx: Fix EEXTEND error handling Sean Christopherson
2019-10-18 10:42 ` Jarkko Sakkinen
2019-10-16 18:37 ` Sean Christopherson [this message]
2019-10-18 10:04 ` [PATCH for_v23 v3 04/12] x86/sgx: Drop mmap_sem before EEXTENDing an enclave page Jarkko Sakkinen
2019-10-16 18:37 ` [PATCH for_v23 v3 05/12] x86/sgx: Remove redundant message from WARN on non-emtpy mm_list Sean Christopherson
2019-10-18 12:08 ` Jarkko Sakkinen
2019-10-16 18:37 ` [PATCH for_v23 v3 06/12] x86/sgx: Fix a memory leak in sgx_encl_destroy() Sean Christopherson
2019-10-18 12:17 ` Jarkko Sakkinen
2019-10-16 18:37 ` [PATCH for_v23 v3 07/12] x86/sgx: WARN on any non-zero return from __eremove() Sean Christopherson
2019-10-16 18:37 ` [PATCH for_v23 v3 08/12] x86/sgx: WARN only once if EREMOVE fails Sean Christopherson
2019-10-16 18:37 ` [PATCH for_v23 v3 09/12] x86/sgx: Split second half of sgx_free_page() to a separate helper Sean Christopherson
2019-10-18 10:06 ` Jarkko Sakkinen
2019-10-22 3:36 ` Sean Christopherson
2019-10-23 11:59 ` Jarkko Sakkinen
2019-10-16 18:37 ` [PATCH for_v23 v3 10/12] x86/sgx: Use the post-reclaim variant of __sgx_free_page() Sean Christopherson
2019-10-16 18:37 ` [PATCH for_v23 v3 11/12] x86/sgx: Don't update free page count if EPC section allocation fails Sean Christopherson
2019-10-16 18:37 ` [PATCH for_v23 v3 12/12] x86/sgx: Reinstate per EPC section free page counts Sean Christopherson
2019-10-18 12:49 ` Jarkko Sakkinen
2019-10-18 12:55 ` Jarkko Sakkinen
2019-10-18 14:30 ` Sean Christopherson
2019-10-21 11:19 ` Jarkko Sakkinen
2019-10-22 19:35 ` Sean Christopherson
2019-10-23 12:02 ` Jarkko Sakkinen
2019-10-17 18:10 ` [PATCH for_v23 v3 00/12] x86/sgx: Bug fixes for v23 Jarkko Sakkinen
2019-10-17 18:12 ` Jarkko Sakkinen
2019-10-18 13:13 ` Jarkko Sakkinen
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