Re: [PATCH 1/2] KVM: x86: fix ordering of cr0 initialization code in vmx_cpu_reset

[Nadav Amit]

Oops.

Anyhow, I see my patch has done a similar change in init_vmcb() , so you may
want to revert it as well.

Nadav

Bruce Rogers <brogers@xxxxxxxx> wrote:

> Commit d28bc9dd25ce reversed the order of two lines which initialize cr0,
> allowing the current (old) cr0 value to mess up vcpu initialization.
> This was observed in the checks for cr0 X86_CR0_WP bit in the context of
> kvm_mmu_reset_context().  Besides, setting vcpu->arch.cr0 after vmx_set_cr0()
> is completely redundant. Change the order back to ensure proper vcpu
> intiialization.
> 
> Signed-off-by: Bruce Rogers <brogers@xxxxxxxx>
> ---
> arch/x86/kvm/vmx.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index e2951b6..21507b4 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -4993,8 +4993,8 @@ 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_set_cr0(vcpu, cr0); /* enter rmode */
> 	vmx->vcpu.arch.cr0 = cr0;
> +	vmx_set_cr0(vcpu, cr0); /* enter rmode */
> 	vmx_set_cr4(vcpu, 0);
> 	vmx_set_efer(vcpu, 0);
> 	vmx_fpu_activate(vcpu);
> -- 
> 1.9.0