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KVM: nVMX: Support direct APIC access from L2

PATCH Applied Jan Kiszka 2 participants 2 messages Dec 16, 2013 – Dec 18, 2013

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Jan Kiszka

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#0 lore raw

PATCH 1/1 KVM: nVMX: Support direct APIC access from L2

It's a pathological case, but still a valid one: If L1 disables APIC virtualization and also allows L2 to directly write to the APIC page, we have to forcibly enable APIC virtualization while in L2 if the in-kernel APIC is in use.

This allows to run the direct interrupt test case in the vmx unit test without x2APIC.

Signed-off-by Jan Kiszka <[email protected]>
---
 arch/x86/kvm/vmx.c | 5 +++++
 1 file changed, 5 insertions(+)
arch/x86/kvm/vmx.c +5 -0
index da04247..7c3ea63 100644
@@ -7771,6 +7771,11 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
 			else
 				vmcs_write64(APIC_ACCESS_ADDR,
 				  page_to_phys(vmx->nested.apic_access_page));
+		} else if (vm_need_virtualize_apic_accesses(vmx->vcpu.kvm)) {
+			exec_control |=
+				SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
+			vmcs_write64(APIC_ACCESS_ADDR,
+				page_to_phys(vcpu->kvm->arch.apic_access_page));
 		}
 
 		vmcs_write32(SECONDARY_VM_EXEC_CONTROL, exec_control);
Signature · 1 line
1.8.1.1.298.ge7eed54
maintainer Applied
#1 lore raw

Il 16/12/2013 12:55, Jan Kiszka ha scritto:

Quoted 20 lines

It's a pathological case, but still a valid one: If L1 disables APIC virtualization and also allows L2 to directly write to the APIC page, we have to forcibly enable APIC virtualization while in L2 if the in-kernel APIC is in use.

This allows to run the direct interrupt test case in the vmx unit test without x2APIC.

Signed-off-by Jan Kiszka <[email protected]>
---
 arch/x86/kvm/vmx.c | 5 +++++
 1 file changed, 5 insertions(+)
arch/x86/kvm/vmx.c +0 -0
index da04247..7c3ea63 100644
@@ -7771,6 +7771,11 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
 			else

arch/x86/kvm/vmx.c static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) · line 7781

Quoted 10 lines
arch/x86/kvm/vmx.c +5 -0
 				vmcs_write64(APIC_ACCESS_ADDR,
 				  page_to_phys(vmx->nested.apic_access_page));
+		} else if (vm_need_virtualize_apic_accesses(vmx->vcpu.kvm)) {
+			exec_control |=
+				SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
+			vmcs_write64(APIC_ACCESS_ADDR,
+				page_to_phys(vcpu->kvm->arch.apic_access_page));
 		}
 
 		vmcs_write32(SECONDARY_VM_EXEC_CONTROL, exec_control);

Applied, thanks.

Paolo