diff options
| author | Avi Kivity <avi@redhat.com> | 2009-09-07 11:12:18 +0300 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2009-12-03 09:32:21 +0200 |
| commit | 18863bdd60f895f3b3ba16b15e8331aee781e8ec (patch) | |
| tree | 2d0e456a8d2dc12def13f2fed386ca9e5a440823 /arch/x86/include | |
| parent | 44ea2b1758d88ad822e65b1c4c21ca6164494e27 (diff) | |
KVM: x86 shared msr infrastructure
The various syscall-related MSRs are fairly expensive to switch. Currently
we switch them on every vcpu preemption, which is far too often:
- if we're switching to a kernel thread (idle task, threaded interrupt,
kernel-mode virtio server (vhost-net), for example) and back, then
there's no need to switch those MSRs since kernel threasd won't
be exiting to userspace.
- if we're switching to another guest running an identical OS, most likely
those MSRs will have the same value, so there's little point in reloading
them.
- if we're running the same OS on the guest and host, the MSRs will have
identical values and reloading is unnecessary.
This patch uses the new user return notifiers to implement last-minute
switching, and checks the msr values to avoid unnecessary reloading.
Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/x86/include')
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 0558ff8c32a..26a74b7bb6b 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -809,4 +809,7 @@ int kvm_cpu_has_interrupt(struct kvm_vcpu *vcpu); int kvm_arch_interrupt_allowed(struct kvm_vcpu *vcpu); int kvm_cpu_get_interrupt(struct kvm_vcpu *v); +void kvm_define_shared_msr(unsigned index, u32 msr); +void kvm_set_shared_msr(unsigned index, u64 val); + #endif /* _ASM_X86_KVM_HOST_H */ |