[PATCH] KVM: SVM: Do not activate AVIC for SEV-enabled guest

From: Suravee Suthikulpanit
Date: Thu Apr 07 2022 - 13:16:15 EST


Since current AVIC implementation cannot support encrypted memory,
inhibit AVIC for SEV-enabled guest.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/svm/avic.c | 3 ++-
arch/x86/kvm/svm/sev.c | 2 ++
3 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 59fc339ba528..6801a0c3890f 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1037,6 +1037,7 @@ struct kvm_x86_msr_filter {
#define APICV_INHIBIT_REASON_X2APIC 5
#define APICV_INHIBIT_REASON_BLOCKIRQ 6
#define APICV_INHIBIT_REASON_ABSENT 7
+#define APICV_INHIBIT_REASON_SEV 8

struct kvm_arch {
unsigned long n_used_mmu_pages;
diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index 4dae5e79f53b..6ffac1b88487 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -1086,7 +1086,8 @@ bool svm_check_apicv_inhibit_reasons(ulong bit)
BIT(APICV_INHIBIT_REASON_IRQWIN) |
BIT(APICV_INHIBIT_REASON_PIT_REINJ) |
BIT(APICV_INHIBIT_REASON_X2APIC) |
- BIT(APICV_INHIBIT_REASON_BLOCKIRQ);
+ BIT(APICV_INHIBIT_REASON_BLOCKIRQ) |
+ BIT(APICV_INHIBIT_REASON_SEV);

return supported & BIT(bit);
}
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index be2883141220..c3af579fcb91 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -259,6 +259,8 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)

INIT_LIST_HEAD(&sev->regions_list);

+ kvm_request_apicv_update(kvm, false, APICV_INHIBIT_REASON_SEV);
+
return 0;

e_free:
--
2.25.1