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. Since there are multiple uses of the "owner" field with different types change the type of sgx_epc_page.owner to "void *. Start epc_pages out with a non-NULL owner while they are in DIRTY state. Fix up the one holdout to provide a non-NULL owner. Refactor the allocation sequence so that changes to/from NULL value happen together with adding/removing the epc_page from a free list while the node->lock is held. Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx> --- arch/x86/kernel/cpu/sgx/encl.c | 5 +++-- arch/x86/kernel/cpu/sgx/encl.h | 2 +- arch/x86/kernel/cpu/sgx/ioctl.c | 2 +- arch/x86/kernel/cpu/sgx/main.c | 21 +++++++++++---------- arch/x86/kernel/cpu/sgx/sgx.h | 4 ++-- 5 files changed, 18 insertions(+), 16 deletions(-) diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c index 001808e3901c..62cf20d5fbf6 100644 --- a/arch/x86/kernel/cpu/sgx/encl.c +++ b/arch/x86/kernel/cpu/sgx/encl.c @@ -667,6 +667,7 @@ int sgx_encl_test_and_clear_young(struct mm_struct *mm, /** * sgx_alloc_va_page() - Allocate a Version Array (VA) page + * @owner: struct sgx_va_page connected to this VA page * * Allocate a free EPC page and convert it to a Version Array (VA) page. * @@ -674,12 +675,12 @@ int sgx_encl_test_and_clear_young(struct mm_struct *mm, * a VA page, * -errno otherwise */ -struct sgx_epc_page *sgx_alloc_va_page(void) +struct sgx_epc_page *sgx_alloc_va_page(void *owner) { struct sgx_epc_page *epc_page; int ret; - epc_page = sgx_alloc_epc_page(NULL, true); + epc_page = sgx_alloc_epc_page(owner, true); if (IS_ERR(epc_page)) return ERR_CAST(epc_page); diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h index fec43ca65065..2a972bc9b2d1 100644 --- a/arch/x86/kernel/cpu/sgx/encl.h +++ b/arch/x86/kernel/cpu/sgx/encl.h @@ -111,7 +111,7 @@ void sgx_encl_put_backing(struct sgx_backing *backing, bool do_write); int sgx_encl_test_and_clear_young(struct mm_struct *mm, struct sgx_encl_page *page); -struct sgx_epc_page *sgx_alloc_va_page(void); +struct sgx_epc_page *sgx_alloc_va_page(void *owner); unsigned int sgx_alloc_va_slot(struct sgx_va_page *va_page); void sgx_free_va_slot(struct sgx_va_page *va_page, unsigned int offset); bool sgx_va_page_full(struct sgx_va_page *va_page); diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c index 83df20e3e633..655ce0bb069d 100644 --- a/arch/x86/kernel/cpu/sgx/ioctl.c +++ b/arch/x86/kernel/cpu/sgx/ioctl.c @@ -30,7 +30,7 @@ static struct sgx_va_page *sgx_encl_grow(struct sgx_encl *encl) if (!va_page) return ERR_PTR(-ENOMEM); - va_page->epc_page = sgx_alloc_va_page(); + va_page->epc_page = sgx_alloc_va_page(va_page); if (IS_ERR(va_page->epc_page)) { err = ERR_CAST(va_page->epc_page); kfree(va_page); diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index 63d3de02bbcc..69743709ec90 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -457,7 +457,7 @@ static bool __init sgx_page_reclaimer_init(void) return true; } -static struct sgx_epc_page *__sgx_alloc_epc_page_from_node(int nid) +static struct sgx_epc_page *__sgx_alloc_epc_page_from_node(void *owner, int nid) { struct sgx_numa_node *node = &sgx_numa_nodes[nid]; struct sgx_epc_page *page = NULL; @@ -471,6 +471,7 @@ static struct sgx_epc_page *__sgx_alloc_epc_page_from_node(int nid) page = list_first_entry(&node->free_page_list, struct sgx_epc_page, list); list_del_init(&page->list); + page->owner = owner; sgx_nr_free_pages--; spin_unlock(&node->lock); @@ -480,6 +481,7 @@ static struct sgx_epc_page *__sgx_alloc_epc_page_from_node(int nid) /** * __sgx_alloc_epc_page() - Allocate an EPC page + * @owner: the owner of the EPC page * * Iterate through NUMA nodes and reserve ia free EPC page to the caller. Start * from the NUMA node, where the caller is executing. @@ -488,14 +490,14 @@ static struct sgx_epc_page *__sgx_alloc_epc_page_from_node(int nid) * - an EPC page: A borrowed EPC pages were available. * - NULL: Out of EPC pages. */ -struct sgx_epc_page *__sgx_alloc_epc_page(void) +struct sgx_epc_page *__sgx_alloc_epc_page(void *owner) { struct sgx_epc_page *page; int nid_of_current = numa_node_id(); int nid = nid_of_current; if (node_isset(nid_of_current, sgx_numa_mask)) { - page = __sgx_alloc_epc_page_from_node(nid_of_current); + page = __sgx_alloc_epc_page_from_node(owner, nid_of_current); if (page) return page; } @@ -506,7 +508,7 @@ struct sgx_epc_page *__sgx_alloc_epc_page(void) if (nid == nid_of_current) break; - page = __sgx_alloc_epc_page_from_node(nid); + page = __sgx_alloc_epc_page_from_node(owner, nid); if (page) return page; } @@ -559,7 +561,7 @@ int sgx_unmark_page_reclaimable(struct sgx_epc_page *page) /** * sgx_alloc_epc_page() - Allocate an EPC page - * @owner: the owner of the EPC page + * @owner: per-caller page owner * @reclaim: reclaim pages if necessary * * Iterate through EPC sections and borrow a free EPC page to the caller. When a @@ -579,11 +581,9 @@ struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim) struct sgx_epc_page *page; for ( ; ; ) { - page = __sgx_alloc_epc_page(); - if (!IS_ERR(page)) { - page->owner = owner; + page = __sgx_alloc_epc_page(owner); + if (!IS_ERR(page)) break; - } if (list_empty(&sgx_active_page_list)) return ERR_PTR(-ENOMEM); @@ -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++; @@ -652,7 +653,7 @@ static bool __init sgx_setup_epc_section(u64 phys_addr, u64 size, for (i = 0; i < nr_pages; i++) { section->pages[i].section = index; section->pages[i].flags = 0; - section->pages[i].owner = NULL; + section->pages[i].owner = (void *)-1; list_add_tail(§ion->pages[i].list, &sgx_dirty_page_list); } diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h index 4628acec0009..cc624778645f 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; }; @@ -77,7 +77,7 @@ static inline void *sgx_get_epc_virt_addr(struct sgx_epc_page *page) return section->virt_addr + index * PAGE_SIZE; } -struct sgx_epc_page *__sgx_alloc_epc_page(void); +struct sgx_epc_page *__sgx_alloc_epc_page(void *owner); void sgx_free_epc_page(struct sgx_epc_page *page); void sgx_mark_page_reclaimable(struct sgx_epc_page *page); -- 2.31.1