x86/sev: Cache the secrets page address

Instead of calling get_secrets_page(), which parses the CC blob every time
to get the secrets page physical address (secrets_pa), save the secrets
page physical address during snp_init() from the CC blob. Since
get_secrets_page() is no longer used, remove the function.

Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20241009092850.197575-4-nikunj@amd.com

diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
index ff19e805e7a167c58a566584338a3ea88ba35836..af50a3846e53a3a844221ac8ddb340797e9601bd 100644 (file)
--- a/arch/x86/coco/sev/core.c
+++ b/arch/x86/coco/sev/core.c
@@ -92,6 +92,9 @@ static struct ghcb *boot_ghcb __section(".data");
 /* Bitmap of SEV features supported by the hypervisor */
 static u64 sev_hv_features __ro_after_init;
 
+/* Secrets page physical address from the CC blob */
+static u64 secrets_pa __ro_after_init;
+
 /* #VC handler runtime per-CPU data */
 struct sev_es_runtime_data {
        struct ghcb ghcb_page;
@@ -695,45 +698,13 @@ void noinstr __sev_es_nmi_complete(void)
        __sev_put_ghcb(&state);
 }
 
-static u64 __init get_secrets_page(void)
-{
-       u64 pa_data = boot_params.cc_blob_address;
-       struct cc_blob_sev_info info;
-       void *map;
-
-       /*
-        * The CC blob contains the address of the secrets page, check if the
-        * blob is present.
-        */
-       if (!pa_data)
-               return 0;
-
-       map = early_memremap(pa_data, sizeof(info));
-       if (!map) {
-               pr_err("Unable to locate SNP secrets page: failed to map the Confidential Computing blob.\n");
-               return 0;
-       }
-       memcpy(&info, map, sizeof(info));
-       early_memunmap(map, sizeof(info));
-
-       /* smoke-test the secrets page passed */
-       if (!info.secrets_phys || info.secrets_len != PAGE_SIZE)
-               return 0;
-
-       return info.secrets_phys;
-}
-
 static u64 __init get_snp_jump_table_addr(void)
 {
        struct snp_secrets_page *secrets;
        void __iomem *mem;
-       u64 pa, addr;
-
-       pa = get_secrets_page();
-       if (!pa)
-               return 0;
+       u64 addr;
 
-       mem = ioremap_encrypted(pa, PAGE_SIZE);
+       mem = ioremap_encrypted(secrets_pa, PAGE_SIZE);
        if (!mem) {
                pr_err("Unable to locate AP jump table address: failed to map the SNP secrets page.\n");
                return 0;
@@ -2273,6 +2244,11 @@ bool __head snp_init(struct boot_params *bp)
        if (!cc_info)
                return false;
 
+       if (cc_info->secrets_phys && cc_info->secrets_len == PAGE_SIZE)
+               secrets_pa = cc_info->secrets_phys;
+       else
+               return false;
+
        setup_cpuid_table(cc_info);
 
        svsm_setup(cc_info);
@@ -2469,16 +2445,11 @@ static struct platform_device sev_guest_device = {
 static int __init snp_init_platform_device(void)
 {
        struct sev_guest_platform_data data;
-       u64 gpa;
 
        if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
                return -ENODEV;
 
-       gpa = get_secrets_page();
-       if (!gpa)
-               return -ENODEV;
-
-       data.secrets_gpa = gpa;
+       data.secrets_gpa = secrets_pa;
        if (platform_device_add_data(&sev_guest_device, &data, sizeof(data)))
                return -ENODEV;