KVM: Add HYPER-V apic access MSRs

Implement HYPER-V apic MSRs. Spec defines three MSRs that speed-up
access to EOI/TPR/ICR apic registers for PV guests.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Vadim Rozenfeld <vrozenfe@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index ba8c045da782..4b224f90087b 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1246,3 +1246,34 @@ int kvm_x2apic_msr_read(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
 
         return 0;
 }
+
+int kvm_hv_vapic_msr_write(struct kvm_vcpu *vcpu, u32 reg, u64 data)
+{
+        struct kvm_lapic *apic = vcpu->arch.apic;
+
+        if (!irqchip_in_kernel(vcpu->kvm))
+                return 1;
+
+        /* if this is ICR write vector before command */
+        if (reg == APIC_ICR)
+                apic_reg_write(apic, APIC_ICR2, (u32)(data >> 32));
+        return apic_reg_write(apic, reg, (u32)data);
+}
+
+int kvm_hv_vapic_msr_read(struct kvm_vcpu *vcpu, u32 reg, u64 *data)
+{
+        struct kvm_lapic *apic = vcpu->arch.apic;
+        u32 low, high = 0;
+
+        if (!irqchip_in_kernel(vcpu->kvm))
+                return 1;
+
+        if (apic_reg_read(apic, reg, 4, &low))
+                return 1;
+        if (reg == APIC_ICR)
+                apic_reg_read(apic, APIC_ICR2, 4, &high);
+
+        *data = (((u64)high) << 32) | low;
+
+        return 0;
+}