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authorNeeraj Upadhyay <Neeraj.Upadhyay@amd.com>2025-08-28 16:51:26 +0530
committerBorislav Petkov (AMD) <bp@alien8.de>2025-09-01 13:18:14 +0200
commitc4074ab87f3483deb15f277f302f199cdb997738 (patch)
tree7d107a5cb37b46c7c43e97db576cfe51d87ad984
parentc8018325dd3e7c75c19b1e9263c358c4c96214f9 (diff)
x86/apic: Enable Secure AVIC in the control MSR
With all the pieces in place now, enable Secure AVIC in the Secure AVIC Control MSR. Any access to x2APIC MSRs are emulated by the hypervisor before Secure AVIC is enabled in the control MSR. Post Secure AVIC enablement, all x2APIC MSR accesses (whether accelerated by AVIC hardware or trapped as a #VC exception) operate on the vCPU's APIC backing page. Signed-off-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tianyu Lan <tiala@microsoft.com> Link: https://lore.kernel.org/20250828112126.209028-1-Neeraj.Upadhyay@amd.com
-rw-r--r--arch/x86/include/asm/msr-index.h2
-rw-r--r--arch/x86/kernel/apic/x2apic_savic.c3
2 files changed, 4 insertions, 1 deletions
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 1291e053e40c..5951344009f1 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -704,6 +704,8 @@
#define MSR_AMD64_SNP_RESV_BIT 19
#define MSR_AMD64_SNP_RESERVED_MASK GENMASK_ULL(63, MSR_AMD64_SNP_RESV_BIT)
#define MSR_AMD64_SAVIC_CONTROL 0xc0010138
+#define MSR_AMD64_SAVIC_EN_BIT 0
+#define MSR_AMD64_SAVIC_EN BIT_ULL(MSR_AMD64_SAVIC_EN_BIT)
#define MSR_AMD64_SAVIC_ALLOWEDNMI_BIT 1
#define MSR_AMD64_SAVIC_ALLOWEDNMI BIT_ULL(MSR_AMD64_SAVIC_ALLOWEDNMI_BIT)
#define MSR_AMD64_RMP_BASE 0xc0010132
diff --git a/arch/x86/kernel/apic/x2apic_savic.c b/arch/x86/kernel/apic/x2apic_savic.c
index 36e6d0dbcc9c..b846de0fbcfa 100644
--- a/arch/x86/kernel/apic/x2apic_savic.c
+++ b/arch/x86/kernel/apic/x2apic_savic.c
@@ -365,7 +365,8 @@ static void savic_setup(void)
if (res != ES_OK)
snp_abort();
- native_wrmsrq(MSR_AMD64_SAVIC_CONTROL, gpa | MSR_AMD64_SAVIC_ALLOWEDNMI);
+ native_wrmsrq(MSR_AMD64_SAVIC_CONTROL,
+ gpa | MSR_AMD64_SAVIC_EN | MSR_AMD64_SAVIC_ALLOWEDNMI);
}
static int savic_probe(void)