The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: bc6f707fc0feec72acc2f49c312eb31d257363a3
Gitweb: https://git.kernel.org/tip/bc6f707fc0feec72acc2f49c312eb31d257363a3
Author: Borislav Petkov (AMD) <bp@xxxxxxxxx>
AuthorDate: Wed, 27 Mar 2024 16:43:16 +01:00
Committer: Borislav Petkov (AMD) <bp@xxxxxxxxx>
CommitterDate: Thu, 04 Apr 2024 10:40:27 +02:00
x86/cc: Add cc_platform_set/_clear() helpers
Add functionality to set and/or clear different attributes of the
machine as a confidential computing platform. Add the first one too:
whether the machine is running as a host for SEV-SNP guests.
Fixes: 216d106c7ff7 ("x86/sev: Add SEV-SNP host initialization support")
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Reviewed-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
Tested-by: Srikanth Aithal <sraithal@xxxxxxx>
Link: https://lore.kernel.org/r/20240327154317.29909-5-bp@xxxxxxxxx
---
arch/x86/coco/core.c | 52 ++++++++++++++++++++++++++++++++++++-
include/linux/cc_platform.h | 12 ++++++++-
2 files changed, 64 insertions(+)
diff --git a/arch/x86/coco/core.c b/arch/x86/coco/core.c
index ddd4efd..b31ef24 100644
--- a/arch/x86/coco/core.c
+++ b/arch/x86/coco/core.c
@@ -20,6 +20,11 @@
enum cc_vendor cc_vendor __ro_after_init = CC_VENDOR_NONE;
u64 cc_mask __ro_after_init;
+static struct cc_attr_flags {
+ __u64 host_sev_snp : 1,
+ __resv : 63;
+} cc_flags;
+
static bool noinstr intel_cc_platform_has(enum cc_attr attr)
{
switch (attr) {
@@ -93,6 +98,9 @@ static bool noinstr amd_cc_platform_has(enum cc_attr attr)
case CC_ATTR_GUEST_SEV_SNP:
return sev_status & MSR_AMD64_SEV_SNP_ENABLED;
+ case CC_ATTR_HOST_SEV_SNP:
+ return cc_flags.host_sev_snp;
+
default:
return false;
}
@@ -153,6 +161,50 @@ u64 cc_mkdec(u64 val)
}
EXPORT_SYMBOL_GPL(cc_mkdec);
+static void amd_cc_platform_clear(enum cc_attr attr)
+{
+ switch (attr) {
+ case CC_ATTR_HOST_SEV_SNP:
+ cc_flags.host_sev_snp = 0;
+ break;
+ default:
+ break;
+ }
+}
+
+void cc_platform_clear(enum cc_attr attr)
+{
+ switch (cc_vendor) {
+ case CC_VENDOR_AMD:
+ amd_cc_platform_clear(attr);
+ break;
+ default:
+ break;
+ }
+}
+
+static void amd_cc_platform_set(enum cc_attr attr)
+{
+ switch (attr) {
+ case CC_ATTR_HOST_SEV_SNP:
+ cc_flags.host_sev_snp = 1;
+ break;
+ default:
+ break;
+ }
+}
+
+void cc_platform_set(enum cc_attr attr)
+{
+ switch (cc_vendor) {
+ case CC_VENDOR_AMD:
+ amd_cc_platform_set(attr);
+ break;
+ default:
+ break;
+ }
+}
+
__init void cc_random_init(void)
{
/*
diff --git a/include/linux/cc_platform.h b/include/linux/cc_platform.h
index cb0d6cd..60693a1 100644
--- a/include/linux/cc_platform.h
+++ b/include/linux/cc_platform.h
@@ -90,6 +90,14 @@ enum cc_attr {
* Examples include TDX Guest.
*/
CC_ATTR_HOTPLUG_DISABLED,
+
+ /**
+ * @CC_ATTR_HOST_SEV_SNP: AMD SNP enabled on the host.
+ *
+ * The host kernel is running with the necessary features
+ * enabled to run SEV-SNP guests.
+ */
+ CC_ATTR_HOST_SEV_SNP,
};
#ifdef CONFIG_ARCH_HAS_CC_PLATFORM
@@ -107,10 +115,14 @@ enum cc_attr {
* * FALSE - Specified Confidential Computing attribute is not active
*/
bool cc_platform_has(enum cc_attr attr);
+void cc_platform_set(enum cc_attr attr);
+void cc_platform_clear(enum cc_attr attr);
#else /* !CONFIG_ARCH_HAS_CC_PLATFORM */
static inline bool cc_platform_has(enum cc_attr attr) { return false; }
+static inline void cc_platform_set(enum cc_attr attr) { }
+static inline void cc_platform_clear(enum cc_attr attr) { }
#endif /* CONFIG_ARCH_HAS_CC_PLATFORM */
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