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KVM: SVM: Add a helper to look up the max physical ID for AVIC

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To help with a future change, add a helper to look up the maximum
physical ID depending on the vCPU AVIC mode. No functional change
intended.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Naveen N Rao (AMD) <naveen@kernel.org>
Link: https://lore.kernel.org/r/0ab9bf5e20a3463a4aa3a5ea9bbbac66beedf1d1.1757009416.git.naveen@kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Naveen N Rao
2025-09-05 00:03:02 +05:30
committed by Sean Christopherson
parent 574ef752d4
commit f2f6e67a56
1 changed files with 20 additions and 6 deletions
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26
arch/x86/kvm/svm/avic.c
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@@ -158,13 +158,31 @@ static void avic_set_x2apic_msr_interception(struct vcpu_svm *svm,
svm->x2avic_msrs_intercepted = intercept;
}
static u32 avic_get_max_physical_id(struct kvm_vcpu *vcpu)
{
u32 arch_max;
if (x2avic_enabled && apic_x2apic_mode(vcpu->arch.apic))
arch_max = X2AVIC_MAX_PHYSICAL_ID;
else
arch_max = AVIC_MAX_PHYSICAL_ID;
/*
* Despite its name, KVM_CAP_MAX_VCPU_ID represents the maximum APIC ID
* plus one, so the max possible APIC ID is one less than that.
*/
return min(vcpu->kvm->arch.max_vcpu_ids - 1, arch_max);
}
static void avic_activate_vmcb(struct vcpu_svm *svm)
{
struct vmcb *vmcb = svm->vmcb01.ptr;
struct kvm *kvm = svm->vcpu.kvm;
struct kvm_vcpu *vcpu = &svm->vcpu;
vmcb->control.int_ctl &= ~(AVIC_ENABLE_MASK | X2APIC_MODE_MASK);
vmcb->control.avic_physical_id &= ~AVIC_PHYSICAL_MAX_INDEX_MASK;
vmcb->control.avic_physical_id |= avic_get_max_physical_id(vcpu);
vmcb->control.int_ctl |= AVIC_ENABLE_MASK;
@@ -177,8 +195,7 @@ static void avic_activate_vmcb(struct vcpu_svm *svm)
*/
if (x2avic_enabled && apic_x2apic_mode(svm->vcpu.arch.apic)) {
vmcb->control.int_ctl |= X2APIC_MODE_MASK;
vmcb->control.avic_physical_id |= min(kvm->arch.max_vcpu_ids - 1,
X2AVIC_MAX_PHYSICAL_ID);
/* Disabling MSR intercept for x2APIC registers */
avic_set_x2apic_msr_interception(svm, false);
} else {
@@ -188,9 +205,6 @@ static void avic_activate_vmcb(struct vcpu_svm *svm)
*/
kvm_make_request(KVM_REQ_TLB_FLUSH_CURRENT, &svm->vcpu);
/* For xAVIC and hybrid-xAVIC modes */
vmcb->control.avic_physical_id |= min(kvm->arch.max_vcpu_ids - 1,
AVIC_MAX_PHYSICAL_ID);
/* Enabling MSR intercept for x2APIC registers */
avic_set_x2apic_msr_interception(svm, true);
}