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| author | Avi Kivity <avi@redhat.com> | 2009-09-07 10:12:18 +0200 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2009-12-03 08:32:21 +0100 |
| commit | 18863bdd60f895f3b3ba16b15e8331aee781e8ec (patch) | |
| tree | 2d0e456a8d2dc12def13f2fed386ca9e5a440823 /arch/x86/kvm/Kconfig | |
| parent | KVM: VMX: Move MSR_KERNEL_GS_BASE out of the vmx autoload msr area (diff) | |
| download | linux-18863bdd60f895f3b3ba16b15e8331aee781e8ec.tar.xz linux-18863bdd60f895f3b3ba16b15e8331aee781e8ec.zip | |
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/kvm/Kconfig')
| -rw-r--r-- | arch/x86/kvm/Kconfig | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig index b84e571f4175..4cd498332466 100644 --- a/arch/x86/kvm/Kconfig +++ b/arch/x86/kvm/Kconfig @@ -28,6 +28,7 @@ config KVM select HAVE_KVM_IRQCHIP select HAVE_KVM_EVENTFD select KVM_APIC_ARCHITECTURE + select USER_RETURN_NOTIFIER ---help--- Support hosting fully virtualized guest machines using hardware virtualization extensions. You will need a fairly recent |