[PATCH v3 10/62] KVM: SVM: Add helper to deduplicate code for getting AVIC backing page

Sean Christopherson
2025-06-11T22:47:14Z

Add a helper to get the physical address of the AVIC backing page, both
to deduplicate code and to prepare for getting the address directly from
apic->regs, at which point it won't be all that obvious that the address
in question is what SVM calls the AVIC backing page.

No functional change intended.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Tested-by: Sairaj Kodilkar <sarunkod@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/svm/avic.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index 4b882148f2c0..c36f7db9252e 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -234,14 +234,18 @@ int avic_vm_init(struct kvm *kvm)
return err;
}

+static phys_addr_t avic_get_backing_page_address(struct vcpu_svm *svm)
+{
+ return __sme_set(page_to_phys(svm->avic_backing_page));
+}
+
void avic_init_vmcb(struct vcpu_svm *svm, struct vmcb *vmcb)
{
struct kvm_svm *kvm_svm = to_kvm_svm(svm->vcpu.kvm);
- phys_addr_t bpa = __sme_set(page_to_phys(svm->avic_backing_page));
phys_addr_t lpa = __sme_set(page_to_phys(kvm_svm->avic_logical_id_table_page));
phys_addr_t ppa = __sme_set(page_to_phys(kvm_svm->avic_physical_id_table_page));

- vmcb->control.avic_backing_page = bpa;
+ vmcb->control.avic_backing_page = avic_get_backing_page_address(svm);
vmcb->control.avic_logical_id = lpa;
vmcb->control.avic_physical_id = ppa;
vmcb->control.avic_vapic_bar = APIC_DEFAULT_PHYS_BASE;
@@ -305,7 +309,7 @@ static int avic_init_backing_page(struct kvm_vcpu *vcpu)
BUILD_BUG_ON(__PHYSICAL_MASK_SHIFT >
fls64(AVIC_PHYSICAL_ID_ENTRY_BACKING_PAGE_MASK));

- new_entry = __sme_set(page_to_phys(svm->avic_backing_page)) |
+ new_entry = avic_get_backing_page_address(svm) |
AVIC_PHYSICAL_ID_ENTRY_VALID_MASK;
WRITE_ONCE(*entry, new_entry);

@@ -845,7 +849,7 @@ get_pi_vcpu_info(struct kvm *kvm, struct kvm_kernel_irq_routing_entry *e,
pr_debug("SVM: %s: use GA mode for irq %u\n", __func__,
irq.vector);
*svm = to_svm(vcpu);
- vcpu_info->pi_desc_addr = __sme_set(page_to_phys((*svm)->avic_backing_page));
+ vcpu_info->pi_desc_addr = avic_get_backing_page_address(*svm);
vcpu_info->vector = irq.vector;

return 0;
@@ -906,7 +910,7 @@ int avic_pi_update_irte(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
enable_remapped_mode = false;

/* Try to enable guest_mode in IRTE */
- pi.base = __sme_set(page_to_phys(svm->avic_backing_page));
+ pi.base = avic_get_backing_page_address(svm);
pi.ga_tag = AVIC_GATAG(to_kvm_svm(kvm)->avic_vm_id,
svm->vcpu.vcpu_id);
pi.is_guest_mode = true;
--
2.50.0.rc1.591.g9c95f17f64-goog