On Tue, 2017-10-10 at 17:32 +0300, Jarkko Sakkinen wrote:
> +static int sgx_dev_init(struct device *parent, bool locked_msrs)
> +{
> + struct sgx_context *sgx_dev;
> + unsigned int eax, ebx, ecx, edx;
> + unsigned long pa;
> + unsigned long size;
> + int ret;
> + int i;
> +
> + pr_info("intel_sgx: " DRV_DESCRIPTION " v" DRV_VERSION "\n");
> +
> + sgx_dev = sgxm_ctx_alloc(parent);
> +
> + sgx_locked_msrs = locked_msrs;
> +
> + cpuid_count(SGX_CPUID, SGX_CPUID_CAPABILITIES, &eax, &ebx, &ecx,
> &edx);
> + /* Only allow misc bits supported by the driver. */
> + sgx_misc_reserved = ~ebx | SGX_MISC_RESERVED_MASK;
> +#ifdef CONFIG_X86_64
> + sgx_encl_size_max_64 = 1ULL << ((edx >> 8) & 0xFF);
> +#endif
> + sgx_encl_size_max_32 = 1ULL << (edx & 0xFF);
> +
> + if (boot_cpu_has(X86_FEATURE_OSXSAVE)) {
> + cpuid_count(SGX_CPUID, SGX_CPUID_ATTRIBUTES, &eax, &ebx,
> &ecx,
> + &edx);
> + sgx_xfrm_mask = (((u64)edx) << 32) + (u64)ecx;
> +
> + for (i = 2; i < 64; i++) {
> + cpuid_count(0x0D, i, &eax, &ebx, &ecx, &edx);
> + if ((1 << i) & sgx_xfrm_mask)
> + sgx_xsave_size_tbl[i] = eax + ebx;
> + }
> + }
> +
> + for (i = 0; i < SGX_MAX_EPC_BANKS; i++) {
> + cpuid_count(SGX_CPUID, i + SGX_CPUID_EPC_BANKS, &eax, &ebx,
> + &ecx, &edx);
> + if (!(eax & 0xf))
> + break;
> +
> + pa = ((u64)(ebx & 0xfffff) << 32) + (u64)(eax & 0xfffff000);
> + size = ((u64)(edx & 0xfffff) << 32) + (u64)(ecx &
> 0xfffff000);
> +
> + dev_info(parent, "EPC bank 0x%lx-0x%lx\n", pa, pa + size);
> +
> + sgx_epc_banks[i].pa = pa;
> + sgx_epc_banks[i].size = size;
> + }
> +
> + sgx_nr_epc_banks = i;
> +
> + for (i = 0; i < sgx_nr_epc_banks; i++) {
> +#ifdef CONFIG_X86_64
> + sgx_epc_banks[i].va = (unsigned long)
> + ioremap_cache(sgx_epc_banks[i].pa,
> + sgx_epc_banks[i].size);
> + if (!sgx_epc_banks[i].va) {
> + sgx_nr_epc_banks = i;
> + ret = -ENOMEM;
> + goto out_iounmap;
> + }
> +#endif
> + ret = sgx_add_epc_bank(sgx_epc_banks[i].pa,
> + sgx_epc_banks[i].size, i);
> + if (ret) {
> + sgx_nr_epc_banks = i + 1;
> + goto out_iounmap;
> + }
> + }
> +
> + ret = sgx_page_cache_init();
> + if (ret)
> + goto out_iounmap;
> +
> + sgx_add_page_wq = alloc_workqueue("intel_sgx-add-page-wq",
> + WQ_UNBOUND | WQ_FREEZABLE, 1);
> + if (!sgx_add_page_wq) {
> + pr_err("intel_sgx: alloc_workqueue() failed\n");
> + ret = -ENOMEM;
> + goto out_iounmap;
> + }
> +
> + ret = cdev_device_add(&sgx_dev->cdev, &sgx_dev->dev);
> + if (ret)
> + goto out_workqueue;
> +
> + return 0;
> +out_workqueue:
> + destroy_workqueue(sgx_add_page_wq);
> +out_iounmap:
sgx_page_cache_teardown() should be called here, else ksgxswapd and the list of
EPC pages will leak.
> +#ifdef CONFIG_X86_64
> + for (i = 0; i < sgx_nr_epc_banks; i++)
> + iounmap((void *)sgx_epc_banks[i].va);
> +#endif
> + return ret;
> +}
...
> +int sgx_add_epc_bank(resource_size_t start, unsigned long size, int bank)
> +{
> + unsigned long i;
> + struct sgx_epc_page *new_epc_page, *entry;
> + struct list_head *parser, *temp;
> +
> + for (i = 0; i < size; i += PAGE_SIZE) {
> + new_epc_page = kzalloc(sizeof(*new_epc_page), GFP_KERNEL);
> + if (!new_epc_page)
> + goto err_freelist;
> + new_epc_page->pa = (start + i) | bank;
> +
> + spin_lock(&sgx_free_list_lock);
> + list_add_tail(&new_epc_page->list, &sgx_free_list);
> + sgx_nr_total_epc_pages++;
> + sgx_nr_free_pages++;
> + spin_unlock(&sgx_free_list_lock);
> + }
> +
> + return 0;
> +err_freelist:
> + list_for_each_safe(parser, temp, &sgx_free_list) {
> + spin_lock(&sgx_free_list_lock);
> + entry = list_entry(parser, struct sgx_epc_page, list);
> + list_del(&entry->list);
> + spin_unlock(&sgx_free_list_lock);
> + kfree(entry);
> + }
> + return -ENOMEM;
> +}
Freeing the entire list on failure does not seem like the appropriate behavior
for this helper func, e.g. the list should be purged by sgx_page_cache_teardown.
Buffering the new pages into a local list and only splicing said list into the
global list upon success is more inline with what I would expect from a helper
func, and also only requires a single lock/unlock.
diff --git drivers/platform/x86/intel_sgx/sgx_page_cache.c
drivers/platform/x86/intel_sgx/sgx_page_cache.c
index f8883d24692a..38496e6296f1 100644
--- drivers/platform/x86/intel_sgx/sgx_page_cache.c
+++ drivers/platform/x86/intel_sgx/sgx_page_cache.c
@@ -397,7 +397,8 @@ int sgx_add_epc_bank(resource_size_t start, unsigned long
size, int bank)
{
unsigned long i;
struct sgx_epc_page *new_epc_page, *entry;
- struct list_head *parser, *temp;
+ unsigned int nr_pages = 0;
+ LIST_HEAD(epc_pages);
for (i = 0; i < size; i += PAGE_SIZE) {
new_epc_page = kzalloc(sizeof(*new_epc_page), GFP_KERNEL);
@@ -405,22 +406,19 @@ int sgx_add_epc_bank(resource_size_t start, unsigned long
size, int bank)
goto err_freelist;
new_epc_page->pa = (start + i) | bank;
- spin_lock(&sgx_free_list_lock);
- list_add_tail(&new_epc_page->list, &sgx_free_list);
- sgx_nr_total_epc_pages++;
- sgx_nr_free_pages++;
- spin_unlock(&sgx_free_list_lock);
+ list_add_tail(&new_epc_page->list, &epc_pages);
+ nr_pages++;
}
+ spin_lock(&sgx_free_list_lock);
+ list_splice_tail(&epc_pages, &sgx_free_list);
+ sgx_nr_total_epc_pages += nr_pages;
+ sgx_nr_free_pages += nr_pages;
+ spin_unlock(&sgx_free_list_lock);
return 0;
err_freelist:
- list_for_each_safe(parser, temp, &sgx_free_list) {
- spin_lock(&sgx_free_list_lock);
- entry = list_entry(parser, struct sgx_epc_page, list);
- list_del(&entry->list);
- spin_unlock(&sgx_free_list_lock);
+ list_for_each_entry(entry, &sgx_free_list, list)
kfree(entry);
- }
return -ENOMEM;
}
