Allocate the list head for the unsanitized pages from heap, and transfer its to ownership to ksgxd, which takes care of destroying it. Remove sgx_dirty_page_list, as a global list is no longer required. Signed-off-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx> --- Depends on https://lore.kernel.org/linux-sgx/20220906000221.34286-1-jarkko@xxxxxxxxxx/T/#t Would this be plausible? --- arch/x86/kernel/cpu/sgx/main.c | 44 ++++++++++++++++++++++++---------- 1 file changed, 31 insertions(+), 13 deletions(-) diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index 0aad028f04d4..6d0e38078d28 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -43,8 +43,6 @@ static nodemask_t sgx_numa_mask; */ static struct sgx_numa_node *sgx_numa_nodes; -static LIST_HEAD(sgx_dirty_page_list); - /* * Reset post-kexec EPC pages to the uninitialized state. The pages are removed * from the input list, and made available for the page allocator. SECS pages @@ -392,16 +390,23 @@ void sgx_reclaim_direct(void) sgx_reclaim_pages(); } -static int ksgxd(void *p) +/* + * The page list head must be allocated from the heap, and its ownership is + * transferred to ksgxd, which takes care of destroying it. + */ +static int ksgxd(void *page_list_ptr) { + struct list_head *page_list = page_list_ptr; + set_freezable(); /* * Sanitize pages in order to recover from kexec(). The 2nd pass is * required for SECS pages, whose child pages blocked EREMOVE. */ - __sgx_sanitize_pages(&sgx_dirty_page_list); - WARN_ON(__sgx_sanitize_pages(&sgx_dirty_page_list)); + __sgx_sanitize_pages(page_list); + WARN_ON(__sgx_sanitize_pages(page_list)); + kfree(page_list); while (!kthread_should_stop()) { if (try_to_freeze()) @@ -420,11 +425,11 @@ static int ksgxd(void *p) return 0; } -static bool __init sgx_page_reclaimer_init(void) +static bool __init sgx_page_reclaimer_init(struct list_head *page_list) { struct task_struct *tsk; - tsk = kthread_run(ksgxd, NULL, "ksgxd"); + tsk = kthread_run(ksgxd, page_list, "ksgxd"); if (IS_ERR(tsk)) return false; @@ -619,7 +624,8 @@ void sgx_free_epc_page(struct sgx_epc_page *page) static bool __init sgx_setup_epc_section(u64 phys_addr, u64 size, unsigned long index, - struct sgx_epc_section *section) + struct sgx_epc_section *section, + struct list_head *page_list) { unsigned long nr_pages = size >> PAGE_SHIFT; unsigned long i; @@ -643,7 +649,7 @@ static bool __init sgx_setup_epc_section(u64 phys_addr, u64 size, section->pages[i].flags = 0; section->pages[i].owner = NULL; section->pages[i].poison = 0; - list_add_tail(§ion->pages[i].list, &sgx_dirty_page_list); + list_add_tail(§ion->pages[i].list, page_list); } return true; @@ -784,7 +790,7 @@ static void __init arch_update_sysfs_visibility(int nid) static void __init arch_update_sysfs_visibility(int nid) {} #endif -static bool __init sgx_page_cache_init(void) +static bool __init sgx_page_cache_init(struct list_head *page_list) { u32 eax, ebx, ecx, edx, type; u64 pa, size; @@ -812,7 +818,7 @@ static bool __init sgx_page_cache_init(void) pr_info("EPC section 0x%llx-0x%llx\n", pa, pa + size - 1); - if (!sgx_setup_epc_section(pa, size, i, &sgx_epc_sections[i])) { + if (!sgx_setup_epc_section(pa, size, i, &sgx_epc_sections[i], page_list)) { pr_err("No free memory for an EPC section\n"); break; } @@ -912,20 +918,32 @@ EXPORT_SYMBOL_GPL(sgx_set_attribute); static int __init sgx_init(void) { + struct list_head *page_list; int ret; int i; if (!cpu_feature_enabled(X86_FEATURE_SGX)) return -ENODEV; - if (!sgx_page_cache_init()) + page_list = kzalloc(sizeof(*page_list), GFP_KERNEL); + if (!page_list) return -ENOMEM; - if (!sgx_page_reclaimer_init()) { + INIT_LIST_HEAD(page_list); + + if (!sgx_page_cache_init(page_list)) { + kfree(page_list); + return -ENOMEM; + } + + if (!sgx_page_reclaimer_init(page_list)) { + kfree(page_list); ret = -ENOMEM; goto err_page_cache; } + /* page_list is now owned by ksgxd. */ + ret = misc_register(&sgx_dev_provision); if (ret) goto err_kthread; -- 2.37.2
