From: Nikunj A Dadhania Date: Mon, 6 Jan 2025 12:46:21 +0000 (+0530) Subject: virt: sev-guest: Remove is_vmpck_empty() helper X-Git-Tag: v6.14-rc1~191^2~10 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=8234177d2027e52126e40472fe5807f4e94b19a3;p=thirdparty%2Fkernel%2Flinux.git virt: sev-guest: Remove is_vmpck_empty() helper Remove is_vmpck_empty() which uses a local array allocation to check if the VMPCK is empty and replace it with memchr_inv() to directly determine if the VMPCK is empty without additional memory allocation. [ bp: Massage commit message. ] Suggested-by: Borislav Petkov Signed-off-by: Nikunj A Dadhania Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20250106124633.1418972-2-nikunj@amd.com --- diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c index b699771be029c..62328d0b2cb6a 100644 --- a/drivers/virt/coco/sev-guest/sev-guest.c +++ b/drivers/virt/coco/sev-guest/sev-guest.c @@ -63,16 +63,6 @@ MODULE_PARM_DESC(vmpck_id, "The VMPCK ID to use when communicating with the PSP. /* Mutex to serialize the shared buffer access and command handling. */ static DEFINE_MUTEX(snp_cmd_mutex); -static bool is_vmpck_empty(struct snp_msg_desc *mdesc) -{ - char zero_key[VMPCK_KEY_LEN] = {0}; - - if (mdesc->vmpck) - return !memcmp(mdesc->vmpck, zero_key, VMPCK_KEY_LEN); - - return true; -} - /* * If an error is received from the host or AMD Secure Processor (ASP) there * are two options. Either retry the exact same encrypted request or discontinue @@ -335,7 +325,7 @@ static int snp_send_guest_request(struct snp_msg_desc *mdesc, struct snp_guest_r guard(mutex)(&snp_cmd_mutex); /* Check if the VMPCK is not empty */ - if (is_vmpck_empty(mdesc)) { + if (!mdesc->vmpck || !memchr_inv(mdesc->vmpck, 0, VMPCK_KEY_LEN)) { pr_err_ratelimited("VMPCK is disabled\n"); return -ENOTTY; } @@ -1024,7 +1014,7 @@ static int __init sev_guest_probe(struct platform_device *pdev) } /* Verify that VMPCK is not zero. */ - if (is_vmpck_empty(mdesc)) { + if (!memchr_inv(mdesc->vmpck, 0, VMPCK_KEY_LEN)) { dev_err(dev, "Empty VMPCK%d communication key\n", vmpck_id); goto e_unmap; }