Hi Joao,
On 10/1/2024 6:04 PM, Joao Martins wrote:
On 30/09/2024 06:50, Suravee Suthikulpanit wrote:
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index dd4682857c12..921b6de80e24 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -448,6 +448,7 @@
#define X86_FEATURE_SME_COHERENT (19*32+10) /* AMD hardware-enforced cache coherency */
#define X86_FEATURE_DEBUG_SWAP (19*32+14) /* "debug_swap" AMD SEV-ES full debug state swap support */
#define X86_FEATURE_SVSM (19*32+28) /* "svsm" SVSM present */
+#define X86_FEATURE_HV_INUSE_WR_ALLOWED (19*32+30) /* Write to in-use hypervisor-owned pages allowed */
/* AMD-defined Extended Feature 2 EAX, CPUID level 0x80000021 (EAX), word 20 */
#define X86_FEATURE_NO_NESTED_DATA_BP (20*32+ 0) /* No Nested Data Breakpoints */
diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index 4b74ea91f4e6..42f2caf17d6a 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -1199,6 +1199,12 @@ bool avic_hardware_setup(void)
return false;
}
+ if (cc_platform_has(CC_ATTR_HOST_SEV_SNP) &&
+ !boot_cpu_has(X86_FEATURE_HV_INUSE_WR_ALLOWED)) {
+ pr_warn("AVIC disabled: missing HvInUseWrAllowed on SNP-enabled system");
+ return false;
+ }
+
Wouldn't be better to make this is APICv inhibit to allow non-SNP guests to work
with AVIC?
I was considering the APICV inhibit as well, and decided to go with
disabling AVIC since it does not require additional
APICV_INHIBIT_REASON_XXX flag, and we can simply disable AVIC support
during kvm-amd driver initialization.
After rethink this, it is better to use per-VM APICv inhibition instead
since certain AVIC data structures will be needed for secure AVIC
support in the future.
I will update this patch and send out V2.
Thanks,
Suravee
