From 9ee73970c03edb68146ceb1ba2a7033c99a5e017 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Tue, 6 Mar 2012 14:16:33 +0200 Subject: [PATCH] KVM: VMX: Fix delayed load of shared MSRs 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 --- arch/x86/kvm/vmx.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 124a0952a040..4a722a0b8e13 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -2210,6 +2210,9 @@ 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); break; } ret = kvm_set_msr_common(vcpu, msr_index, data); -- 2.20.1