Re: [PATCH v14 03/13] x86/sev: Add Secure TSC support for SNP guests

[Borislav Petkov]

On Mon, Nov 11, 2024 at 02:16:00PM +0530, Nikunj A. Dadhania wrote:
> That was the reason I had not implemented "free" counterpart.

Then let's simplify this too because it is kinda silly right now:

---
diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
index a72400704421..efddccf4b2c6 100644
--- a/arch/x86/coco/sev/core.c
+++ b/arch/x86/coco/sev/core.c
@@ -96,7 +96,7 @@ static u64 sev_hv_features __ro_after_init;
 /* Secrets page physical address from the CC blob */
 static u64 secrets_pa __ro_after_init;
 
-static struct snp_msg_desc *snp_mdesc;
+static struct snp_msg_desc snp_mdesc;
 
 /* Secure TSC values read using TSC_INFO SNP Guest request */
 static u64 snp_tsc_scale __ro_after_init;
@@ -2749,19 +2749,13 @@ EXPORT_SYMBOL_GPL(snp_msg_init);
 
 struct snp_msg_desc *snp_msg_alloc(void)
 {
-	struct snp_msg_desc *mdesc;
+	struct snp_msg_desc *mdesc = &snp_mdesc;
 
 	BUILD_BUG_ON(sizeof(struct snp_guest_msg) > PAGE_SIZE);
 
-	if (snp_mdesc)
-		return snp_mdesc;
-
-	mdesc = kzalloc(sizeof(struct snp_msg_desc), GFP_KERNEL);
-	if (!mdesc)
-		return ERR_PTR(-ENOMEM);
+	memset(mdesc, 0, sizeof(struct snp_msg_desc));
 
-	mdesc->secrets = (__force struct snp_secrets_page *)ioremap_encrypted(secrets_pa,
-									      PAGE_SIZE);
+	mdesc->secrets = (__force struct snp_secrets_page *)ioremap_encrypted(secrets_pa, PAGE_SIZE);
 	if (!mdesc->secrets)
 		return ERR_PTR(-ENODEV);
 
@@ -2783,8 +2777,6 @@ struct snp_msg_desc *snp_msg_alloc(void)
 	mdesc->input.resp_gpa = __pa(mdesc->response);
 	mdesc->input.data_gpa = __pa(mdesc->certs_data);
 
-	snp_mdesc = mdesc;
-
 	return mdesc;
 
 e_free_response:

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette