@@ -233,41 +233,52 @@ static void sgx_etrack(struct sgx_epc_page *epc_page)
}
static int __sgx_ewb(struct sgx_encl *encl,
- struct sgx_encl_page *encl_page,
- struct page *backing)
+ struct sgx_encl_page *encl_page)
{
struct sgx_page_info pginfo;
+ struct page *backing;
void *epc;
void *va;
int ret;
- pginfo.srcpge = (unsigned long)kmap_atomic(backing);
+ backing = sgx_get_backing(encl, encl_page);
+ if (IS_ERR(backing)) {
+ ret = PTR_ERR(backing);
+ sgx_warn(encl, "pinning the backing page for EWB failed with %d\n",
+ ret);
+ return ret;
+ }
+
epc = sgx_get_epc_page(encl_page->epc_page);
va = sgx_get_epc_page(encl_page->va_page->epc_page);
+ pginfo.srcpge = (unsigned long)kmap_atomic(backing);
pginfo.pcmd = (unsigned long)&encl_page->pcmd;
pginfo.linaddr = 0;
pginfo.secs = 0;
ret = __ewb(&pginfo, epc,
(void *)((unsigned long)va + encl_page->va_offset));
+ kunmap_atomic((void *)(unsigned long)pginfo.srcpge);
sgx_put_epc_page(va);
sgx_put_epc_page(epc);
- kunmap_atomic((void *)(unsigned long)pginfo.srcpge);
+ sgx_put_backing(backing, true);
return ret;
}
static bool sgx_ewb(struct sgx_encl *encl,
- struct sgx_encl_page *entry,
- struct page *backing)
+ struct sgx_encl_page *entry)
{
- int ret = __sgx_ewb(encl, entry, backing);
+ int ret = __sgx_ewb(encl, entry);
+
+ if (ret < 0)
+ return false;
if (ret == SGX_NOT_TRACKED) {
/* slow path, IPI needed */
smp_call_function(sgx_ipi_cb, NULL, 1);
- ret = __sgx_ewb(encl, entry, backing);
+ ret = __sgx_ewb(encl, entry);
}
if (ret) {
@@ -294,11 +305,8 @@ static void sgx_write_pages(struct sgx_encl *encl, struct list_head *src)
{
struct sgx_encl_page *entry;
struct sgx_encl_page *tmp;
- struct page *pages[SGX_NR_SWAP_CLUSTER_MAX + 1];
struct vm_area_struct *evma;
unsigned int free_flags;
- int cnt = 0;
- int i = 0;
if (list_empty(src))
return;
@@ -316,25 +324,14 @@ static void sgx_write_pages(struct sgx_encl *encl, struct list_head *src)
continue;
}
- pages[cnt] = sgx_get_backing(encl, entry);
- if (IS_ERR(pages[cnt])) {
- list_del(&entry->load_list);
- list_add_tail(&entry->load_list, &encl->load_list);
- entry->flags &= ~SGX_ENCL_PAGE_RESERVED;
- continue;
- }
-
zap_vma_ptes(evma, entry->addr, PAGE_SIZE);
sgx_eblock(entry->epc_page);
- cnt++;
}
/* ETRACK */
sgx_etrack(encl->secs_page.epc_page);
/* EWB */
- i = 0;
-
while (!list_empty(src)) {
entry = list_first_entry(src, struct sgx_encl_page,
load_list);
@@ -344,29 +341,21 @@ static void sgx_write_pages(struct sgx_encl *encl, struct list_head *src)
evma = sgx_find_vma(encl, entry->addr);
if (evma) {
- if (sgx_ewb(encl, entry, pages[i]))
+ if (sgx_ewb(encl, entry))
free_flags = SGX_FREE_SKIP_EREMOVE;
encl->secs_child_cnt--;
}
sgx_free_encl_page(entry, encl, free_flags);
- sgx_put_backing(pages[i++], evma);
}
- /* Allow SECS page eviction only when the encl is initialized. */
- if (!encl->secs_child_cnt &&
- (encl->flags & SGX_ENCL_INITIALIZED)) {
- pages[cnt] = sgx_get_backing(encl, &encl->secs_page);
- if (!IS_ERR(pages[cnt])) {
- free_flags = 0;
- if (sgx_ewb(encl, &encl->secs_page, pages[cnt]))
- free_flags = SGX_FREE_SKIP_EREMOVE;
-
- encl->flags |= SGX_ENCL_SECS_EVICTED;
+ if (!encl->secs_child_cnt && (encl->flags & SGX_ENCL_INITIALIZED)) {
+ free_flags = 0;
+ if (sgx_ewb(encl, &encl->secs_page))
+ free_flags = SGX_FREE_SKIP_EREMOVE;
- sgx_free_encl_page(&encl->secs_page, encl, free_flags);
- sgx_put_backing(pages[cnt], true);
- }
+ encl->flags |= SGX_ENCL_SECS_EVICTED;
+ sgx_free_encl_page(&encl->secs_page, encl, free_flags);
}
mutex_unlock(&encl->lock);
Now that sgx_ewb flow has a sane error recovery flow we can simplify sgx_write_pages() significantly by moving the pinning of backing page into sgx_ewb(). This was not possible before as in some situations pinning could legally fail. [Marked as RFC because it requires a pending patch set. I implemented this to show of benefits of the introduced recovery flow.] Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> --- drivers/platform/x86/intel_sgx_page_cache.c | 63 ++++++++++++----------------- 1 file changed, 26 insertions(+), 37 deletions(-)