On Mon, 24 Sep 2018, Sean Christopherson wrote: > On Sat, 2018-09-22 at 09:56 +0800, kvm-owner@xxxxxxxxxxxxxxx wrote: > > vmx->vcpu.arch.cr0 will be set in vmx_set_cr0(). > > > > This patch removes duplicate cr0 set in vmx_vcpu_reset(). > > > > Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx> > > --- > > arch/x86/kvm/vmx.c | 1 - > > 1 file changed, 1 deletion(-) > > > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > > index 1519f030fd73..b1e1d63a4970 100644 > > --- a/arch/x86/kvm/vmx.c > > +++ b/arch/x86/kvm/vmx.c > > @@ -6734,7 +6734,6 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) > > vmcs_write16(VIRTUAL_PROCESSOR_ID, vmx->vpid); > > > > cr0 = X86_CR0_NW | X86_CR0_CD | X86_CR0_ET; > > - vmx->vcpu.arch.cr0 = cr0; > > Initializing arch.cr0 prior to vmx_set_cr0() is necessary because it > might be queried by vmx_set_cr0(), e.g. via is_paging(). A stale cr0 > could trigger side effects in vmx_set_cr0() related to toggling cr0 > bits, which we don't want. And these side effects are completely undocumented. So if that store needs to happen before calling vmx_set_cr0() then this really wants a comment. Thanks, tglx
