[PATCH v6 04/17] KVM: SVM: Update max number of vCPUs supported for x2AVIC mode

Suravee Suthikulpanit
2022-05-19T10:28:29Z

xAVIC and x2AVIC modes can support diffferent number of vcpus.
Update existing logics to support each mode accordingly.

Also, modify the maximum physical APIC ID for AVIC to 255 to reflect
the actual value supported by the architecture.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
arch/x86/include/asm/svm.h | 12 +++++++++---
arch/x86/kvm/svm/avic.c | 8 +++++---
2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index 2c2a104b777e..4c26b0d47d76 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -258,10 +258,16 @@ enum avic_ipi_failure_cause {

/*
- * 0xff is broadcast, so the max index allowed for physical APIC ID
- * table is 0xfe. APIC IDs above 0xff are reserved.
+ * For AVIC, the max index allowed for physical APIC ID
+ * table is 0xff (255).
*/
-#define AVIC_MAX_PHYSICAL_ID_COUNT 0xff
+#define AVIC_MAX_PHYSICAL_ID 0XFEULL
+
+/*
+ * For x2AVIC, the max index allowed for physical APIC ID
+ * table is 0x1ff (511).
+ */
+#define X2AVIC_MAX_PHYSICAL_ID 0x1FFUL

#define AVIC_HPA_MASK ~((0xFFFULL << 52) | 0xFFF)
#define VMCB_AVIC_APIC_BAR_MASK 0xFFFFFFFFFF000ULL
diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index 7d4e73e95acd..6b89303034e3 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -179,7 +179,7 @@ void avic_init_vmcb(struct vcpu_svm *svm, struct vmcb *vmcb)
vmcb->control.avic_backing_page = bpa & AVIC_HPA_MASK;
vmcb->control.avic_logical_id = lpa & AVIC_HPA_MASK;
vmcb->control.avic_physical_id = ppa & AVIC_HPA_MASK;
- vmcb->control.avic_physical_id |= AVIC_MAX_PHYSICAL_ID_COUNT;
+ vmcb->control.avic_physical_id |= AVIC_MAX_PHYSICAL_ID;
vmcb->control.avic_vapic_bar = APIC_DEFAULT_PHYS_BASE & VMCB_AVIC_APIC_BAR_MASK;

if (kvm_apicv_activated(svm->vcpu.kvm))
@@ -194,7 +194,8 @@ static u64 *avic_get_physical_id_entry(struct kvm_vcpu *vcpu,
u64 *avic_physical_id_table;
struct kvm_svm *kvm_svm = to_kvm_svm(vcpu->kvm);

- if (index >= AVIC_MAX_PHYSICAL_ID_COUNT)
+ if ((avic_mode == AVIC_MODE_X1 && index > AVIC_MAX_PHYSICAL_ID) ||
+ (avic_mode == AVIC_MODE_X2 && index > X2AVIC_MAX_PHYSICAL_ID))
return NULL;

avic_physical_id_table = page_address(kvm_svm->avic_physical_id_table_page);
@@ -241,7 +242,8 @@ static int avic_init_backing_page(struct kvm_vcpu *vcpu)
int id = vcpu->vcpu_id;
struct vcpu_svm *svm = to_svm(vcpu);

- if (id >= AVIC_MAX_PHYSICAL_ID_COUNT)
+ if ((avic_mode == AVIC_MODE_X1 && id > AVIC_MAX_PHYSICAL_ID) ||
+ (avic_mode == AVIC_MODE_X2 && id > X2AVIC_MAX_PHYSICAL_ID))
return -EINVAL;

if (!vcpu->arch.apic->regs)
--
2.25.1