Messages in this thread Patch in this message | | | From | Tony Luck <> | Subject | [PATCH v3 1/7] x86/sgx: Provide indication of life-cycle of EPC pages | Date | Wed, 28 Jul 2021 13:46:47 -0700 |
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SGX EPC pages go through the following life cycle:
DIRTY ---> FREE ---> IN-USE --\ ^ | \-----------------/
Recovery action for poison for a DIRTY or FREE page is simple. Just make sure never to allocate the page. IN-USE pages need some extra handling.
It would be good to use the sgx_epc_page->owner field as an indicator of where an EPC page is currently in that cycle (owner != NULL means the EPC page is IN-USE). But there is one caller, sgx_alloc_va_page(), that calls with NULL.
Make the following changes:
1) Change the type of "owner" to "void *" (it can have other types besides "struct sgx_encl_page *). 2) Add a check to sgx_free_epc_page(). If the caller specified the owner as NULL, then set the owner field to self-reference the SGX epc page itself. 3) Reset owner to NULL in sgx_free_epc_page().
Signed-off-by: Tony Luck <tony.luck@intel.com> --- arch/x86/kernel/cpu/sgx/main.c | 3 ++- arch/x86/kernel/cpu/sgx/sgx.h | 2 +- 2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index 63d3de02bbcc..17d09186a6c2 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -581,7 +581,7 @@ struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim) for ( ; ; ) { page = __sgx_alloc_epc_page(); if (!IS_ERR(page)) { - page->owner = owner; + page->owner = owner ? owner : page; break; } @@ -624,6 +624,7 @@ void sgx_free_epc_page(struct sgx_epc_page *page) spin_lock(&node->lock); + page->owner = NULL; list_add_tail(&page->list, &node->free_page_list); sgx_nr_free_pages++; diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h index 4628acec0009..4e1a410b8a62 100644 --- a/arch/x86/kernel/cpu/sgx/sgx.h +++ b/arch/x86/kernel/cpu/sgx/sgx.h @@ -29,7 +29,7 @@ struct sgx_epc_page { unsigned int section; unsigned int flags; - struct sgx_encl_page *owner; + void *owner; struct list_head list; }; -- 2.29.2
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