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Message-Id: <20220922171057.1236139-9-kristen@linux.intel.com>
Date: Thu, 22 Sep 2022 10:10:45 -0700
From: Kristen Carlson Accardi <kristen@...ux.intel.com>
To: linux-kernel@...r.kernel.org, linux-sgx@...r.kernel.org,
cgroups@...r.kernel.org, Jarkko Sakkinen <jarkko@...nel.org>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>
Cc: Kristen Carlson Accardi <kristen@...ux.intel.com>,
Sean Christopherson <seanjc@...gle.com>
Subject: [RFC PATCH 08/20] x86/sgx: Add EPC page flags to identify type of page
From: Sean Christopherson <sean.j.christopherson@...el.com>
Create new flags to help identify whether a page is an enclave page
or a va page and save the page type when the page is recorded.
Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
Signed-off-by: Kristen Carlson Accardi <kristen@...ux.intel.com>
Cc: Sean Christopherson <seanjc@...gle.com>
---
arch/x86/kernel/cpu/sgx/encl.c | 6 +++---
arch/x86/kernel/cpu/sgx/ioctl.c | 4 ++--
arch/x86/kernel/cpu/sgx/main.c | 20 ++++++++++----------
arch/x86/kernel/cpu/sgx/sgx.h | 8 +++++++-
4 files changed, 22 insertions(+), 16 deletions(-)
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
index ad611c06798f..672b302f3688 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -252,7 +252,7 @@ static struct sgx_encl_page *__sgx_encl_load_page(struct sgx_encl *encl,
epc_page = sgx_encl_eldu(&encl->secs, NULL);
if (IS_ERR(epc_page))
return ERR_CAST(epc_page);
- sgx_record_epc_page(epc_page, 0);
+ sgx_record_epc_page(epc_page, SGX_EPC_PAGE_ENCLAVE);
}
epc_page = sgx_encl_eldu(entry, encl->secs.epc_page);
@@ -260,7 +260,7 @@ static struct sgx_encl_page *__sgx_encl_load_page(struct sgx_encl *encl,
return ERR_CAST(epc_page);
encl->secs_child_cnt++;
- sgx_record_epc_page(entry->epc_page, SGX_EPC_PAGE_RECLAIMER_TRACKED);
+ sgx_record_epc_page(entry->epc_page, SGX_EPC_PAGE_ENCLAVE_RECLAIMABLE);
return entry;
}
@@ -1221,7 +1221,7 @@ struct sgx_epc_page *sgx_alloc_va_page(struct sgx_encl *encl, bool reclaim)
sgx_encl_free_epc_page(epc_page);
return ERR_PTR(-EFAULT);
}
- sgx_record_epc_page(epc_page, 0);
+ sgx_record_epc_page(epc_page, SGX_EPC_PAGE_VERSION_ARRAY);
epc_page->owner = encl;
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index aca80a3f38a1..c91cc6a01232 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -114,7 +114,7 @@ static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
encl->attributes = secs->attributes;
encl->attributes_mask = SGX_ATTR_DEBUG | SGX_ATTR_MODE64BIT | SGX_ATTR_KSS;
- sgx_record_epc_page(encl->secs.epc_page, 0);
+ sgx_record_epc_page(encl->secs.epc_page, SGX_EPC_PAGE_ENCLAVE);
/* Set only after completion, as encl->lock has not been taken. */
set_bit(SGX_ENCL_CREATED, &encl->flags);
@@ -325,7 +325,7 @@ static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long src,
goto err_out;
}
- sgx_record_epc_page(encl_page->epc_page, SGX_EPC_PAGE_RECLAIMER_TRACKED);
+ sgx_record_epc_page(encl_page->epc_page, SGX_EPC_PAGE_ENCLAVE_RECLAIMABLE);
mutex_unlock(&encl->lock);
mmap_read_unlock(current->mm);
return ret;
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 085c06fdc359..3c0d33b72896 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -304,6 +304,8 @@ static void sgx_reclaim_pages(void)
epc_page = list_first_entry(&sgx_global_lru.reclaimable,
struct sgx_epc_page, list);
encl_page = epc_page->owner;
+ if (WARN_ON_ONCE(!(epc_page->flags & SGX_EPC_PAGE_ENCLAVE)))
+ continue;
if (kref_get_unless_zero(&encl_page->encl->refcount) != 0) {
epc_page->flags |= SGX_EPC_PAGE_RECLAIM_IN_PROGRESS;
@@ -360,8 +362,7 @@ static void sgx_reclaim_pages(void)
sgx_reclaimer_write(epc_page, &backing[i++]);
kref_put(&encl_page->encl->refcount, sgx_encl_release);
- epc_page->flags &= ~(SGX_EPC_PAGE_RECLAIMER_TRACKED |
- SGX_EPC_PAGE_RECLAIM_IN_PROGRESS);
+ epc_page->flags &= ~SGX_EPC_PAGE_RECLAIM_FLAGS;
sgx_free_epc_page(epc_page);
}
@@ -496,6 +497,7 @@ struct sgx_epc_page *__sgx_alloc_epc_page(void)
/**
* sgx_record_epc_page() - Add a page to the LRU tracking
* @page: EPC page
+ * @flags: Reclaim flags for the page.
*
* Mark a page with the specified flags and add it to the appropriate
* (un)reclaimable list.
@@ -525,18 +527,16 @@ void sgx_record_epc_page(struct sgx_epc_page *page, unsigned long flags)
int sgx_drop_epc_page(struct sgx_epc_page *page)
{
spin_lock(&sgx_global_lru.lock);
- if (page->flags & SGX_EPC_PAGE_RECLAIMER_TRACKED) {
- /* The page is being reclaimed. */
- if (page->flags & SGX_EPC_PAGE_RECLAIM_IN_PROGRESS) {
- spin_unlock(&sgx_global_lru.lock);
- return -EBUSY;
- }
-
- page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
+ if ((page->flags & SGX_EPC_PAGE_RECLAIMER_TRACKED) &&
+ (page->flags & SGX_EPC_PAGE_RECLAIM_IN_PROGRESS)) {
+ spin_unlock(&sgx_global_lru.lock);
+ return -EBUSY;
}
list_del(&page->list);
spin_unlock(&sgx_global_lru.lock);
+ page->flags &= ~SGX_EPC_PAGE_RECLAIM_FLAGS;
+
return 0;
}
diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h
index 284d0cda9e36..76eae4ecbf87 100644
--- a/arch/x86/kernel/cpu/sgx/sgx.h
+++ b/arch/x86/kernel/cpu/sgx/sgx.h
@@ -31,8 +31,14 @@
/* page flag to indicate reclaim is in progress */
#define SGX_EPC_PAGE_RECLAIM_IN_PROGRESS BIT(2)
+#define SGX_EPC_PAGE_ENCLAVE BIT(3)
+#define SGX_EPC_PAGE_VERSION_ARRAY BIT(4)
+#define SGX_EPC_PAGE_ENCLAVE_RECLAIMABLE (SGX_EPC_PAGE_ENCLAVE | \
+ SGX_EPC_PAGE_RECLAIMER_TRACKED)
#define SGX_EPC_PAGE_RECLAIM_FLAGS (SGX_EPC_PAGE_RECLAIMER_TRACKED | \
- SGX_EPC_PAGE_RECLAIM_IN_PROGRESS)
+ SGX_EPC_PAGE_RECLAIM_IN_PROGRESS | \
+ SGX_EPC_PAGE_ENCLAVE | \
+ SGX_EPC_PAGE_VERSION_ARRAY)
struct sgx_epc_page {
unsigned int section;
--
2.37.3
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