Remove sgx_pin_mm and sgx_unpin_mm and instead directly call down_read and up_read on encl->mm->mmap_sem. Add a check for SGX_ENCL_DEAD in sgx_isolate_pages as it previously relied on sgx_pin_mm to check for the enclave being dead. The other code in sgx_(un)pin_mm was either redundant and/or unnecessary. As both consumers of sgx_pin_mm lock the encl after sgx_pin_mm, it is more accurate to check SGX_ENCL_DEAD after the consumer locks the encl. Locking the enclave for the purposes of checking SGX_ENCL_DEAD is not functionally necessary when acquiring mmap_sem. Incrementing mm_count when locking encl->mm->mmap_sem is unnecessary as mm_count is incremented when encl->mmu_notifier is registered and is not decremented until the notifier is released in sgx_encl_release. Signed-off-by: Sean Christopherson <sean.j.christopherson(a)intel.com&gt; --- drivers/platform/x86/intel_sgx.h | 2 -- drivers/platform/x86/intel_sgx_ioctl.c | 9 +++------ drivers/platform/x86/intel_sgx_page_cache.c | 12 ++++++------ drivers/platform/x86/intel_sgx_util.c | 27 --------------------------- 4 files changed, 9 insertions(+), 41 deletions(-) diff --git a/drivers/platform/x86/intel_sgx.h b/drivers/platform/x86/intel_sgx.h index adb5b17..a4c8265 100644 --- a/drivers/platform/x86/intel_sgx.h +++ b/drivers/platform/x86/intel_sgx.h @@ -217,8 +217,6 @@ int sgx_eremove(struct sgx_epc_page *epc_page); struct vm_area_struct *sgx_find_vma(struct sgx_encl *encl, unsigned long addr); void sgx_zap_tcs_ptes(struct sgx_encl *encl, struct vm_area_struct *vma); -bool sgx_pin_mm(struct sgx_encl *encl); -void sgx_unpin_mm(struct sgx_encl *encl); void sgx_invalidate(struct sgx_encl *encl); int sgx_find_encl(struct mm_struct *mm, unsigned long addr, struct vm_area_struct **vma); diff --git a/drivers/platform/x86/intel_sgx_ioctl.c b/drivers/platform/x86/intel_sgx_ioctl.c index e0e2f14..32739cf 100644 --- a/drivers/platform/x86/intel_sgx_ioctl.c +++ b/drivers/platform/x86/intel_sgx_ioctl.c @@ -220,10 +220,7 @@ static bool sgx_process_add_page_req(struct sgx_add_page_req *req) if (IS_ERR(epc_page)) return false; - if (!sgx_pin_mm(encl)) { - sgx_free_page(epc_page, encl, 0); - return false; - } + down_read(&encl->mm->mmap_sem); mutex_lock(&encl->lock); @@ -271,12 +268,12 @@ static bool sgx_process_add_page_req(struct sgx_add_page_req *req) list_add_tail(&encl_page->load_list, &encl->load_list); mutex_unlock(&encl->lock); - sgx_unpin_mm(encl); + up_read(&encl->mm->mmap_sem); return true; out: sgx_free_page(epc_page, encl, 0); mutex_unlock(&encl->lock); - sgx_unpin_mm(encl); + up_read(&encl->mm->mmap_sem); return false; } diff --git a/drivers/platform/x86/intel_sgx_page_cache.c b/drivers/platform/x86/intel_sgx_page_cache.c index e4f6b95..35dbf8d 100644 --- a/drivers/platform/x86/intel_sgx_page_cache.c +++ b/drivers/platform/x86/intel_sgx_page_cache.c @@ -195,6 +195,9 @@ static void sgx_isolate_pages(struct sgx_encl *encl, mutex_lock(&encl->lock); + if (encl->flags & SGX_ENCL_DEAD) + goto out; + for (i = 0; i < nr_to_scan; i++) { if (list_empty(&encl->load_list)) break; @@ -211,7 +214,7 @@ static void sgx_isolate_pages(struct sgx_encl *encl, list_move_tail(&entry->load_list, &encl->load_list); } } - +out: mutex_unlock(&encl->lock); } @@ -392,14 +395,11 @@ static void sgx_swap_pages(unsigned long nr_to_scan) if (!encl) goto out; - if (!sgx_pin_mm(encl)) - goto out_enclave; - + down_read(&encl->mm->mmap_sem); sgx_isolate_pages(encl, &cluster, nr_to_scan); sgx_write_pages(encl, &cluster); - sgx_unpin_mm(encl); + up_read(&encl->mm->mmap_sem); -out_enclave: kref_put(&encl->refcount, sgx_encl_release); out: kref_put(&ctx->refcount, sgx_tgid_ctx_release); diff --git a/drivers/platform/x86/intel_sgx_util.c b/drivers/platform/x86/intel_sgx_util.c index 234a5fb..2671f00 100644 --- a/drivers/platform/x86/intel_sgx_util.c +++ b/drivers/platform/x86/intel_sgx_util.c @@ -147,33 +147,6 @@ void sgx_zap_tcs_ptes(struct sgx_encl *encl, struct vm_area_struct *vma) } } -bool sgx_pin_mm(struct sgx_encl *encl) -{ - mutex_lock(&encl->lock); - if (encl->flags & SGX_ENCL_DEAD) { - mutex_unlock(&encl->lock); - return false; - } - - atomic_inc(&encl->mm->mm_count); - mutex_unlock(&encl->lock); - - down_read(&encl->mm->mmap_sem); - - if (encl->flags & SGX_ENCL_DEAD) { - sgx_unpin_mm(encl); - return false; - } - - return true; -} - -void sgx_unpin_mm(struct sgx_encl *encl) -{ - up_read(&encl->mm->mmap_sem); - mmdrop(encl->mm); -} - void sgx_invalidate(struct sgx_encl *encl) { struct vm_area_struct *vma; -- 2.7.4