KVM: PPC: Convert MSR to shared page

One of the most obvious registers to share with the guest directly is the
MSR. The MSR contains the "interrupts enabled" flag which the guest has to
toggle in critical sections.

So in order to bring the overhead of interrupt en- and disabling down, let's
put msr into the shared page. Keep in mind that even though you can fully read
its contents, writing to it doesn't always update all state. There are a few
safe fields that don't require hypervisor interaction. See the documentation
for a list of MSR bits that are safe to be set from inside the guest.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 10 insertions, 10 deletions

diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 8d4e35f5372c..4ec9d49a1cb9 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -62,7 +62,7 @@ void kvmppc_dump_vcpu(struct kvm_vcpu *vcpu)
 {
 	int i;
 
-	printk("pc:   %08lx msr:  %08lx\n", vcpu->arch.pc, vcpu->arch.msr);
+	printk("pc:   %08lx msr:  %08llx\n", vcpu->arch.pc, vcpu->arch.shared->msr);
 	printk("lr:   %08lx ctr:  %08lx\n", vcpu->arch.lr, vcpu->arch.ctr);
 	printk("srr0: %08lx srr1: %08lx\n", vcpu->arch.srr0, vcpu->arch.srr1);
 
@@ -169,34 +169,34 @@ static int kvmppc_booke_irqprio_deliver(struct kvm_vcpu *vcpu,
 		break;
 	case BOOKE_IRQPRIO_CRITICAL:
 	case BOOKE_IRQPRIO_WATCHDOG:
-		allowed = vcpu->arch.msr & MSR_CE;
+		allowed = vcpu->arch.shared->msr & MSR_CE;
 		msr_mask = MSR_ME;
 		break;
 	case BOOKE_IRQPRIO_MACHINE_CHECK:
-		allowed = vcpu->arch.msr & MSR_ME;
+		allowed = vcpu->arch.shared->msr & MSR_ME;
 		msr_mask = 0;
 		break;
 	case BOOKE_IRQPRIO_EXTERNAL:
 	case BOOKE_IRQPRIO_DECREMENTER:
 	case BOOKE_IRQPRIO_FIT:
-		allowed = vcpu->arch.msr & MSR_EE;
+		allowed = vcpu->arch.shared->msr & MSR_EE;
 		msr_mask = MSR_CE|MSR_ME|MSR_DE;
 		break;
 	case BOOKE_IRQPRIO_DEBUG:
-		allowed = vcpu->arch.msr & MSR_DE;
+		allowed = vcpu->arch.shared->msr & MSR_DE;
 		msr_mask = MSR_ME;
 		break;
 	}
 
 	if (allowed) {
 		vcpu->arch.srr0 = vcpu->arch.pc;
-		vcpu->arch.srr1 = vcpu->arch.msr;
+		vcpu->arch.srr1 = vcpu->arch.shared->msr;
 		vcpu->arch.pc = vcpu->arch.ivpr | vcpu->arch.ivor[priority];
 		if (update_esr == true)
 			vcpu->arch.esr = vcpu->arch.queued_esr;
 		if (update_dear == true)
 			vcpu->arch.dear = vcpu->arch.queued_dear;
-		kvmppc_set_msr(vcpu, vcpu->arch.msr & msr_mask);
+		kvmppc_set_msr(vcpu, vcpu->arch.shared->msr & msr_mask);
 
 		clear_bit(priority, &vcpu->arch.pending_exceptions);
 	}
@@ -265,7 +265,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
 		break;
 
 	case BOOKE_INTERRUPT_PROGRAM:
-		if (vcpu->arch.msr & MSR_PR) {
+		if (vcpu->arch.shared->msr & MSR_PR) {
 			/* Program traps generated by user-level software must be handled
 			 * by the guest kernel. */
 			kvmppc_core_queue_program(vcpu, vcpu->arch.fault_esr);
@@ -467,7 +467,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
 int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
 {
 	vcpu->arch.pc = 0;
-	vcpu->arch.msr = 0;
+	vcpu->arch.shared->msr = 0;
 	kvmppc_set_gpr(vcpu, 1, (16<<20) - 8); /* -8 for the callee-save LR slot */
 
 	vcpu->arch.shadow_pid = 1;
@@ -490,7 +490,7 @@ int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
 	regs->ctr = vcpu->arch.ctr;
 	regs->lr = vcpu->arch.lr;
 	regs->xer = kvmppc_get_xer(vcpu);
-	regs->msr = vcpu->arch.msr;
+	regs->msr = vcpu->arch.shared->msr;
 	regs->srr0 = vcpu->arch.srr0;
 	regs->srr1 = vcpu->arch.srr1;
 	regs->pid = vcpu->arch.pid;