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authorAlexander Graf <agraf@suse.de>2010-07-29 14:47:43 +0200
committerAvi Kivity <avi@redhat.com>2010-10-24 10:50:43 +0200
commit666e7252a15b7fc4a116e65deaf6da5e4ce660e3 (patch)
treee7a56f03cb4e181eacd4f481fb3e6e038ad05b82 /arch/powerpc/kvm/book3s_paired_singles.c
parent96bc451a153297bf1f99ef2d633d512ea349ae7a (diff)
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>
Diffstat (limited to 'arch/powerpc/kvm/book3s_paired_singles.c')
-rw-r--r--arch/powerpc/kvm/book3s_paired_singles.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/powerpc/kvm/book3s_paired_singles.c b/arch/powerpc/kvm/book3s_paired_singles.c
index 474f2e24050a..626e6efaa79f 100644
--- a/arch/powerpc/kvm/book3s_paired_singles.c
+++ b/arch/powerpc/kvm/book3s_paired_singles.c
@@ -165,9 +165,10 @@ static inline void kvmppc_sync_qpr(struct kvm_vcpu *vcpu, int rt)
static void kvmppc_inject_pf(struct kvm_vcpu *vcpu, ulong eaddr, bool is_store)
{
u64 dsisr;
+ struct kvm_vcpu_arch_shared *shared = vcpu->arch.shared;
- vcpu->arch.msr = kvmppc_set_field(vcpu->arch.msr, 33, 36, 0);
- vcpu->arch.msr = kvmppc_set_field(vcpu->arch.msr, 42, 47, 0);
+ shared->msr = kvmppc_set_field(shared->msr, 33, 36, 0);
+ shared->msr = kvmppc_set_field(shared->msr, 42, 47, 0);
vcpu->arch.dear = eaddr;
/* Page Fault */
dsisr = kvmppc_set_field(0, 33, 33, 1);
@@ -658,7 +659,7 @@ int kvmppc_emulate_paired_single(struct kvm_run *run, struct kvm_vcpu *vcpu)
if (!kvmppc_inst_is_paired_single(vcpu, inst))
return EMULATE_FAIL;
- if (!(vcpu->arch.msr & MSR_FP)) {
+ if (!(vcpu->arch.shared->msr & MSR_FP)) {
kvmppc_book3s_queue_irqprio(vcpu, BOOK3S_INTERRUPT_FP_UNAVAIL);
return EMULATE_AGAIN;
}

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