From: Haitao Huang <haitao.huang@xxxxxxxxxxxxxxx> Enclave Page Cache(EPC) memory can be swapped out to regular system memory, and the consumed memory should be charged to a proper mem_cgroup. Currently the selection of mem_cgroup to charge is done in sgx_encl_get_mem_cgroup(). But it considers all contexts other than the ksgxd thread are user processes. With the new EPC cgroup implementation, the swapping can also happen in EPC cgroup work-queue threads. In those cases, it improperly selects the root mem_cgroup to charge for the RAM usage. Remove current_is_ksgxd() and change sgx_encl_get_mem_cgroup() to take an additional argument to explicitly specify the mm struct to charge for allocations. Callers from background kthreads not associated with a charging mm struct would set it to NULL, while callers in user process contexts set it to current->mm. Internally, it handles the case when the charging mm given is NULL, by searching for an mm struct from enclave's mm_list. Signed-off-by: Haitao Huang <haitao.huang@xxxxxxxxxxxxxxx> Reported-by: Mikko Ylinen <mikko.ylinen@xxxxxxxxxxxxxxx> Reviewed-by: Kai Huang <kai.huang@xxxxxxxxx> Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx> Tested-by: Mikko Ylinen <mikko.ylinen@xxxxxxxxxxxxxxx> Tested-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx> --- V10: - Pass mm struct instead of a boolean 'indirect'. (Dave, Jarkko) V9: - Reduce number of if statements. (Tim) V8: - Limit text paragraphs to 80 characters wide. (Jarkko) --- arch/x86/kernel/cpu/sgx/encl.c | 29 ++++++++++++++-------------- arch/x86/kernel/cpu/sgx/encl.h | 3 +-- arch/x86/kernel/cpu/sgx/epc_cgroup.c | 11 +++++++---- arch/x86/kernel/cpu/sgx/main.c | 29 +++++++++++++--------------- arch/x86/kernel/cpu/sgx/sgx.h | 2 +- 5 files changed, 37 insertions(+), 37 deletions(-) diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c index f474179b6f77..7b77dad41daf 100644 --- a/arch/x86/kernel/cpu/sgx/encl.c +++ b/arch/x86/kernel/cpu/sgx/encl.c @@ -993,23 +993,23 @@ static int __sgx_encl_get_backing(struct sgx_encl *encl, unsigned long page_inde } /* - * When called from ksgxd, returns the mem_cgroup of a struct mm stored - * in the enclave's mm_list. When not called from ksgxd, just returns - * the mem_cgroup of the current task. + * Find the mem_cgroup to charge for memory allocated on behalf of an enclave. + * + * Used in sgx_encl_alloc_backing() for backing store allocation. + * + * Return the mem_cgroup of the given charge_mm. Otherwise return the mem_cgroup + * of a struct mm stored in the enclave's mm_list. */ -static struct mem_cgroup *sgx_encl_get_mem_cgroup(struct sgx_encl *encl) +static struct mem_cgroup *sgx_encl_get_mem_cgroup(struct sgx_encl *encl, + struct mm_struct *charge_mm) { struct mem_cgroup *memcg = NULL; struct sgx_encl_mm *encl_mm; int idx; - /* - * If called from normal task context, return the mem_cgroup - * of the current task's mm. The remainder of the handling is for - * ksgxd. - */ - if (!current_is_ksgxd()) - return get_mem_cgroup_from_mm(current->mm); + /* Use the charge_mm if given. */ + if (charge_mm) + return get_mem_cgroup_from_mm(charge_mm); /* * Search the enclave's mm_list to find an mm associated with @@ -1047,8 +1047,9 @@ static struct mem_cgroup *sgx_encl_get_mem_cgroup(struct sgx_encl *encl) * @encl: an enclave pointer * @page_index: enclave page index * @backing: data for accessing backing storage for the page + * @charge_mm: the mm to charge for the allocation * - * When called from ksgxd, sets the active memcg from one of the + * When charge_mm is NULL, sets the active memcg from one of the * mms in the enclave's mm_list prior to any backing page allocation, * in order to ensure that shmem page allocations are charged to the * enclave. Create a backing page for loading data back into an EPC page with @@ -1060,9 +1061,9 @@ static struct mem_cgroup *sgx_encl_get_mem_cgroup(struct sgx_encl *encl) * -errno otherwise. */ int sgx_encl_alloc_backing(struct sgx_encl *encl, unsigned long page_index, - struct sgx_backing *backing) + struct sgx_backing *backing, struct mm_struct *charge_mm) { - struct mem_cgroup *encl_memcg = sgx_encl_get_mem_cgroup(encl); + struct mem_cgroup *encl_memcg = sgx_encl_get_mem_cgroup(encl, charge_mm); struct mem_cgroup *memcg = set_active_memcg(encl_memcg); int ret; diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h index fe15ade02ca1..5ce9d108290f 100644 --- a/arch/x86/kernel/cpu/sgx/encl.h +++ b/arch/x86/kernel/cpu/sgx/encl.h @@ -103,12 +103,11 @@ static inline int sgx_encl_find(struct mm_struct *mm, unsigned long addr, int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start, unsigned long end, unsigned long vm_flags); -bool current_is_ksgxd(void); void sgx_encl_release(struct kref *ref); int sgx_encl_mm_add(struct sgx_encl *encl, struct mm_struct *mm); const cpumask_t *sgx_encl_cpumask(struct sgx_encl *encl); int sgx_encl_alloc_backing(struct sgx_encl *encl, unsigned long page_index, - struct sgx_backing *backing); + struct sgx_backing *backing, struct mm_struct *charge_mm); void sgx_encl_put_backing(struct sgx_backing *backing); int sgx_encl_test_and_clear_young(struct mm_struct *mm, struct sgx_encl_page *page); diff --git a/arch/x86/kernel/cpu/sgx/epc_cgroup.c b/arch/x86/kernel/cpu/sgx/epc_cgroup.c index fdadfb7c05fe..ec7f267d3e7a 100644 --- a/arch/x86/kernel/cpu/sgx/epc_cgroup.c +++ b/arch/x86/kernel/cpu/sgx/epc_cgroup.c @@ -107,6 +107,7 @@ static bool sgx_cgroup_lru_empty(struct misc_cg *root) * sgx_cgroup_reclaim_pages() - reclaim EPC from a cgroup tree * @root: The root of cgroup tree to reclaim from. * @start: The descendant cgroup from which to start the tree walking. + * @charge_mm: The mm to charge for backing store allocation. * * This function performs a pre-order walk in the cgroup tree under the given * root, starting from the node %start, or from the root if %start is NULL. The @@ -126,7 +127,8 @@ static bool sgx_cgroup_lru_empty(struct misc_cg *root) * release the reference if the returned is not used as %start for a subsequent * call. */ -static struct misc_cg *sgx_cgroup_reclaim_pages(struct misc_cg *root, struct misc_cg *start) +static struct misc_cg *sgx_cgroup_reclaim_pages(struct misc_cg *root, struct misc_cg *start, + struct mm_struct *charge_mm) { struct cgroup_subsys_state *css_root, *pos; struct cgroup_subsys_state *next = NULL; @@ -142,7 +144,7 @@ static struct misc_cg *sgx_cgroup_reclaim_pages(struct misc_cg *root, struct mis while (cnt < SGX_NR_TO_SCAN) { sgx_cg = sgx_cgroup_from_misc_cg(css_misc(pos)); - cnt += sgx_reclaim_pages(&sgx_cg->lru); + cnt += sgx_reclaim_pages(&sgx_cg->lru, charge_mm); rcu_read_lock(); @@ -218,7 +220,8 @@ static void sgx_cgroup_reclaim_work_func(struct work_struct *work) * blocked until a worker makes its way through the global work queue. */ while (sgx_cgroup_should_reclaim(sgx_cg)) { - cg_next = sgx_cgroup_reclaim_pages(sgx_cg->cg, cg_next); + /* Indirect reclaim, no mm to charge, so NULL: */ + cg_next = sgx_cgroup_reclaim_pages(sgx_cg->cg, cg_next, NULL); cond_resched(); } @@ -266,7 +269,7 @@ int sgx_cgroup_try_charge(struct sgx_cgroup *sgx_cg, enum sgx_reclaim reclaim) goto out; } - cg_next = sgx_cgroup_reclaim_pages(sgx_cg->cg, cg_next); + cg_next = sgx_cgroup_reclaim_pages(sgx_cg->cg, cg_next, current->mm); cond_resched(); } diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index 2c0a36be7cdd..e91fa5f5348d 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -261,8 +261,8 @@ static void sgx_encl_ewb(struct sgx_epc_page *epc_page, } } -static void sgx_reclaimer_write(struct sgx_epc_page *epc_page, - struct sgx_backing *backing) +static void sgx_reclaimer_write(struct sgx_epc_page *epc_page, struct sgx_backing *backing, + struct mm_struct *charge_mm) { struct sgx_encl_page *encl_page = epc_page->owner; struct sgx_encl *encl = encl_page->encl; @@ -278,7 +278,7 @@ static void sgx_reclaimer_write(struct sgx_epc_page *epc_page, if (!encl->secs_child_cnt && test_bit(SGX_ENCL_INITIALIZED, &encl->flags)) { ret = sgx_encl_alloc_backing(encl, PFN_DOWN(encl->size), - &secs_backing); + &secs_backing, charge_mm); if (ret) goto out; @@ -297,6 +297,7 @@ static void sgx_reclaimer_write(struct sgx_epc_page *epc_page, /** * sgx_reclaim_pages() - Attempt to reclaim a fixed number of pages from an LRU * @lru: The LRU from which pages are reclaimed. + * @charge_mm: The mm to charge for backing store allocation. * * Take a fixed number of pages from the head of a given LRU and reclaim them to * the enclave's private shmem files. Skip the pages, which have been accessed @@ -312,7 +313,7 @@ static void sgx_reclaimer_write(struct sgx_epc_page *epc_page, * * Return: Number of pages attempted for reclamation. */ -unsigned int sgx_reclaim_pages(struct sgx_epc_lru_list *lru) +unsigned int sgx_reclaim_pages(struct sgx_epc_lru_list *lru, struct mm_struct *charge_mm) { struct sgx_epc_page *chunk[SGX_NR_TO_SCAN]; struct sgx_backing backing[SGX_NR_TO_SCAN]; @@ -352,7 +353,7 @@ unsigned int sgx_reclaim_pages(struct sgx_epc_lru_list *lru) page_index = PFN_DOWN(encl_page->desc - encl_page->encl->base); mutex_lock(&encl_page->encl->lock); - ret = sgx_encl_alloc_backing(encl_page->encl, page_index, &backing[i]); + ret = sgx_encl_alloc_backing(encl_page->encl, page_index, &backing[i], charge_mm); if (ret) { mutex_unlock(&encl_page->encl->lock); goto skip; @@ -384,7 +385,7 @@ unsigned int sgx_reclaim_pages(struct sgx_epc_lru_list *lru) continue; encl_page = epc_page->owner; - sgx_reclaimer_write(epc_page, &backing[i]); + sgx_reclaimer_write(epc_page, &backing[i], charge_mm); kref_put(&encl_page->encl->refcount, sgx_encl_release); epc_page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED; @@ -401,9 +402,9 @@ static bool sgx_should_reclaim_global(unsigned long watermark) sgx_can_reclaim_global(); } -static void sgx_reclaim_pages_global(void) +static void sgx_reclaim_pages_global(struct mm_struct *charge_mm) { - sgx_reclaim_pages(&sgx_global_lru); + sgx_reclaim_pages(&sgx_global_lru, charge_mm); } /* @@ -414,7 +415,7 @@ static void sgx_reclaim_pages_global(void) void sgx_reclaim_direct(void) { if (sgx_should_reclaim_global(SGX_NR_LOW_PAGES)) - sgx_reclaim_pages_global(); + sgx_reclaim_pages_global(current->mm); } static int ksgxd(void *p) @@ -437,7 +438,8 @@ static int ksgxd(void *p) sgx_should_reclaim_global(SGX_NR_HIGH_PAGES)); if (sgx_should_reclaim_global(SGX_NR_HIGH_PAGES)) - sgx_reclaim_pages_global(); + /* Indirect reclaim, no mm to charge, so NULL: */ + sgx_reclaim_pages_global(NULL); cond_resched(); } @@ -460,11 +462,6 @@ static bool __init sgx_page_reclaimer_init(void) return true; } -bool current_is_ksgxd(void) -{ - return current == ksgxd_tsk; -} - static struct sgx_epc_page *__sgx_alloc_epc_page_from_node(int nid) { struct sgx_numa_node *node = &sgx_numa_nodes[nid]; @@ -619,7 +616,7 @@ struct sgx_epc_page *sgx_alloc_epc_page(void *owner, enum sgx_reclaim reclaim) break; } - sgx_reclaim_pages_global(); + sgx_reclaim_pages_global(current->mm); cond_resched(); } diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h index 4dc04f4d046c..4dc067519504 100644 --- a/arch/x86/kernel/cpu/sgx/sgx.h +++ b/arch/x86/kernel/cpu/sgx/sgx.h @@ -136,7 +136,7 @@ void sgx_reclaim_direct(void); void sgx_mark_page_reclaimable(struct sgx_epc_page *page); int sgx_unmark_page_reclaimable(struct sgx_epc_page *page); struct sgx_epc_page *sgx_alloc_epc_page(void *owner, enum sgx_reclaim reclaim); -unsigned int sgx_reclaim_pages(struct sgx_epc_lru_list *lru); +unsigned int sgx_reclaim_pages(struct sgx_epc_lru_list *lru, struct mm_struct *charge_mm); void sgx_ipi_cb(void *info); -- 2.43.0