1 files changed, 30 insertions, 12 deletions

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 63be07d7c782..c7180cb5f464 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2471,11 +2471,25 @@ int kvm_x2apic_icr_write(struct kvm_lapic *apic, u64 data)
 	data &= ~APIC_ICR_BUSY;
 
 	kvm_apic_send_ipi(apic, (u32)data, (u32)(data >> 32));
-	kvm_lapic_set_reg64(apic, APIC_ICR, data);
+	if (kvm_x86_ops.x2apic_icr_is_split) {
+		kvm_lapic_set_reg(apic, APIC_ICR, data);
+		kvm_lapic_set_reg(apic, APIC_ICR2, data >> 32);
+	} else {
+		kvm_lapic_set_reg64(apic, APIC_ICR, data);
+	}
 	trace_kvm_apic_write(APIC_ICR, data);
 	return 0;
 }
 
+static u64 kvm_x2apic_icr_read(struct kvm_lapic *apic)
+{
+	if (kvm_x86_ops.x2apic_icr_is_split)
+		return (u64)kvm_lapic_get_reg(apic, APIC_ICR) |
+		       (u64)kvm_lapic_get_reg(apic, APIC_ICR2) << 32;
+
+	return kvm_lapic_get_reg64(apic, APIC_ICR);
+}
+
 /* emulate APIC access in a trap manner */
 void kvm_apic_write_nodecode(struct kvm_vcpu *vcpu, u32 offset)
 {
@@ -2493,7 +2507,7 @@ void kvm_apic_write_nodecode(struct kvm_vcpu *vcpu, u32 offset)
 	 * maybe-unecessary write, and both are in the noise anyways.
 	 */
 	if (apic_x2apic_mode(apic) && offset == APIC_ICR)
-		WARN_ON_ONCE(kvm_x2apic_icr_write(apic, kvm_lapic_get_reg64(apic, APIC_ICR)));
+		WARN_ON_ONCE(kvm_x2apic_icr_write(apic, kvm_x2apic_icr_read(apic)));
 	else
 		kvm_lapic_reg_write(apic, offset, kvm_lapic_get_reg(apic, offset));
 }
@@ -3013,18 +3027,22 @@ static int kvm_apic_state_fixup(struct kvm_vcpu *vcpu,
 
 		/*
 		 * In x2APIC mode, the LDR is fixed and based on the id.  And
-		 * ICR is internally a single 64-bit register, but needs to be
-		 * split to ICR+ICR2 in userspace for backwards compatibility.
+		 * if the ICR is _not_ split, ICR is internally a single 64-bit
+		 * register, but needs to be split to ICR+ICR2 in userspace for
+		 * backwards compatibility.
 		 */
-		if (set) {
+		if (set)
 			*ldr = kvm_apic_calc_x2apic_ldr(x2apic_id);
 
-			icr = __kvm_lapic_get_reg(s->regs, APIC_ICR) |
-			      (u64)__kvm_lapic_get_reg(s->regs, APIC_ICR2) << 32;
-			__kvm_lapic_set_reg64(s->regs, APIC_ICR, icr);
-		} else {
-			icr = __kvm_lapic_get_reg64(s->regs, APIC_ICR);
-			__kvm_lapic_set_reg(s->regs, APIC_ICR2, icr >> 32);
+		if (!kvm_x86_ops.x2apic_icr_is_split) {
+			if (set) {
+				icr = __kvm_lapic_get_reg(s->regs, APIC_ICR) |
+				      (u64)__kvm_lapic_get_reg(s->regs, APIC_ICR2) << 32;
+				__kvm_lapic_set_reg64(s->regs, APIC_ICR, icr);
+			} else {
+				icr = __kvm_lapic_get_reg64(s->regs, APIC_ICR);
+				__kvm_lapic_set_reg(s->regs, APIC_ICR2, icr >> 32);
+			}
 		}
 	}
 
@@ -3222,7 +3240,7 @@ static int kvm_lapic_msr_read(struct kvm_lapic *apic, u32 reg, u64 *data)
 	u32 low;
 
 	if (reg == APIC_ICR) {
-		*data = kvm_lapic_get_reg64(apic, APIC_ICR);
+		*data = kvm_x2apic_icr_read(apic);
 		return 0;
 	}