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authorAvi Kivity <avi@redhat.com>2012-05-09 16:10:43 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-05-12 09:32:20 -0700
commit044873c9fc637a88225f0e01bedb9daee04524ed (patch)
parent9c895160d25a76c21b65bad141b08e8d4f99afef (diff)
KVM: VMX: Fix delayed load of shared MSRs
(cherry picked from commit 9ee73970c03edb68146ceb1ba2a7033c99a5e017) Shared MSRs (MSR_*STAR and related) are stored in both vmx->guest_msrs and in the CPU registers, but vmx_set_msr() only updated memory. Prior to 46199f33c2953, this didn't matter, since we called vmx_load_host_state(), which scheduled a vmx_save_host_state(), which re-synchronized the CPU state, but now we don't, so the CPU state will not be synchronized until the next exit to host userspace. This mostly affects nested vmx workloads, which play with these MSRs a lot. Fix by loading the MSR eagerly. Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 3b4c8d8ad906..fafb3256ea5e 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2219,6 +2219,9 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data)
msr = find_msr_entry(vmx, msr_index);
if (msr) {
msr->data = data;
+ if (msr - vmx->guest_msrs < vmx->save_nmsrs)
+ kvm_set_shared_msr(msr->index, msr->data,
+ msr->mask);
ret = kvm_set_msr_common(vcpu, msr_index, data);