* [PATCH 0/2] x86/sgx: Take away EREMOVE from sgx_free_epc_page()
@ 2021-01-11 22:36 jarkko
2021-01-11 22:36 ` [PATCH 1/2] x86/sgx: Remove a warn " jarkko
2021-01-11 22:36 ` [PATCH 2/2] x86/sgx: Wipe out EREMOVE " jarkko
0 siblings, 2 replies; 3+ messages in thread
From: jarkko @ 2021-01-11 22:36 UTC (permalink / raw)
To: linux-sgx
Cc: kai.huang, dave.hansen, haitao.huang, jarkko, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, H. Peter Anvin, x86
From: "jarkko@kernel.org" <jarkko@kernel.org>
Refactor EREMOVE out of sgx_free_epc_page() since it is only used in
one function.
I re-organized my Git a bit in order to keep track of things:
- 'master' bleading edge and 'next' ready PR ready branch
- 'numa' has nearly finished stuff, including the patches I'm
posting now.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
jarkko@kernel.org (2):
x86/sgx: Remove a warn from sgx_free_epc_page()
x86/sgx: Wipe out EREMOVE from sgx_free_epc_page()
arch/x86/kernel/cpu/sgx/encl.c | 15 ++++++++++++++-
arch/x86/kernel/cpu/sgx/main.c | 12 ++++--------
2 files changed, 18 insertions(+), 9 deletions(-)
--
2.29.2
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH 1/2] x86/sgx: Remove a warn from sgx_free_epc_page()
2021-01-11 22:36 [PATCH 0/2] x86/sgx: Take away EREMOVE from sgx_free_epc_page() jarkko
@ 2021-01-11 22:36 ` jarkko
2021-01-11 22:36 ` [PATCH 2/2] x86/sgx: Wipe out EREMOVE " jarkko
1 sibling, 0 replies; 3+ messages in thread
From: jarkko @ 2021-01-11 22:36 UTC (permalink / raw)
To: linux-sgx
Cc: kai.huang, dave.hansen, haitao.huang, jarkko, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, x86, H. Peter Anvin
From: "jarkko@kernel.org" <jarkko@kernel.org>
Remove SGX_EPC_PAGE_RECLAIMER_TRACKED check and warning. This cannot
happen, as enclave pages are freed only at the time when encl->refcount
triggers, i.e. when both VFS and the page reclaimer have given up on
their references.
Signed-off-by: jarkko@kernel.org <jarkko@kernel.org>
---
arch/x86/kernel/cpu/sgx/main.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 0da510763c47..b2996cb63a8a 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -636,8 +636,6 @@ void sgx_free_epc_page(struct sgx_epc_page *page)
struct sgx_epc_section *section = &sgx_epc_sections[page->section];
int ret;
- WARN_ON_ONCE(page->flags & SGX_EPC_PAGE_RECLAIMER_TRACKED);
-
ret = __eremove(sgx_get_epc_virt_addr(page));
if (WARN_ONCE(ret, "EREMOVE returned %d (0x%x)", ret, ret))
return;
--
2.29.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH 2/2] x86/sgx: Wipe out EREMOVE from sgx_free_epc_page()
2021-01-11 22:36 [PATCH 0/2] x86/sgx: Take away EREMOVE from sgx_free_epc_page() jarkko
2021-01-11 22:36 ` [PATCH 1/2] x86/sgx: Remove a warn " jarkko
@ 2021-01-11 22:36 ` jarkko
1 sibling, 0 replies; 3+ messages in thread
From: jarkko @ 2021-01-11 22:36 UTC (permalink / raw)
To: linux-sgx
Cc: kai.huang, dave.hansen, haitao.huang, jarkko, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, x86, H. Peter Anvin
From: "jarkko@kernel.org" <jarkko@kernel.org>
Encapsulate the snippet in sgx_free_epc_page() concerning EREMOVE to
sgx_reset_epc_page(), which is a static helper function for
sgx_encl_release(). It's the only function existing, which deals with
initialized pages.
Signed-off-by: jarkko@kernel.org <jarkko@kernel.org>
---
arch/x86/kernel/cpu/sgx/encl.c | 15 ++++++++++++++-
arch/x86/kernel/cpu/sgx/main.c | 10 ++++------
2 files changed, 18 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
index fe7256db6e73..de4bc4226d99 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -389,6 +389,16 @@ const struct vm_operations_struct sgx_vm_ops = {
.access = sgx_vma_access,
};
+
+static void sgx_reset_epc_page(struct sgx_epc_page *epc_page)
+{
+ int ret;
+
+ ret = __eremove(sgx_get_epc_virt_addr(page));
+ if (WARN_ONCE(ret, "EREMOVE returned %d (0x%x)", ret, ret))
+ return;
+}
+
/**
* sgx_encl_release - Destroy an enclave instance
* @kref: address of a kref inside &sgx_encl
@@ -412,6 +422,7 @@ void sgx_encl_release(struct kref *ref)
if (sgx_unmark_page_reclaimable(entry->epc_page))
continue;
+ sgx_reset_epc_page(entry->epc_page);
sgx_free_epc_page(entry->epc_page);
encl->secs_child_cnt--;
entry->epc_page = NULL;
@@ -423,6 +434,7 @@ void sgx_encl_release(struct kref *ref)
xa_destroy(&encl->page_array);
if (!encl->secs_child_cnt && encl->secs.epc_page) {
+ sgx_reset_epc_page(encl->secs.epc_page);
sgx_free_epc_page(encl->secs.epc_page);
encl->secs.epc_page = NULL;
}
@@ -431,7 +443,8 @@ void sgx_encl_release(struct kref *ref)
va_page = list_first_entry(&encl->va_pages, struct sgx_va_page,
list);
list_del(&va_page->list);
- sgx_free_epc_page(va_page->epc_page);
+ sgx_reset_epc_page(entry->epc_page);
+ sgx_free_epc_page(entry->epc_page);
kfree(va_page);
}
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index b2996cb63a8a..89d52fb56d4b 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -629,16 +629,14 @@ struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim)
* sgx_free_epc_page() - Free an EPC page
* @page: an EPC page
*
- * Call EREMOVE for an EPC page and insert it back to the list of free pages.
+ * Put the EPC page back to the list of free pages. It's the callers
+ * responsibility to make sure that the page is in uninitialized state In other
+ * words, do EREMOVE, EWB or whatever operation is necessary before calling
+ * this function.
*/
void sgx_free_epc_page(struct sgx_epc_page *page)
{
struct sgx_epc_section *section = &sgx_epc_sections[page->section];
- int ret;
-
- ret = __eremove(sgx_get_epc_virt_addr(page));
- if (WARN_ONCE(ret, "EREMOVE returned %d (0x%x)", ret, ret))
- return;
spin_lock(§ion->lock);
list_add_tail(&page->list, §ion->page_list);
--
2.29.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
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