KVM: SVM: Only save/restore MSRs when needed
authorAnthony Liguori <aliguori@us.ibm.com>
Sun, 29 Apr 2007 08:56:06 +0000 (11:56 +0300)
committerAvi Kivity <avi@qumranet.com>
Thu, 3 May 2007 07:52:32 +0000 (10:52 +0300)
commit94dfbdb3894eda2f673b70e20da2743c4a8d3968
tree74e7a4a31a72ed0e3753e9390189d2e8132ecf0e
parent2807696c3791d6dd1dcf20f022eaa2dc7615bc5d
KVM: SVM: Only save/restore MSRs when needed

We only have to save/restore MSR_GS_BASE on every VMEXIT.  The rest can be
saved/restored when we leave the VCPU.  Since we don't emulate the DEBUGCTL
MSRs and the guest cannot write to them, we don't have to worry about
saving/restoring them at all.

This shaves a whopping 40% off raw vmexit costs on AMD.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
drivers/kvm/kvm_svm.h
drivers/kvm/svm.c