Re: [RFC PATCH] KVM: SVM: Use do_machine_check to pass MCE to the host

[Sean Christopherson <sean.j.christopherson@intel.com>]

On Sat, Apr 11, 2020 at 05:36:27PM +0200, Uros Bizjak wrote:
> Use do_machine_check instead of INT $12 to pass MCE to the host,
> the same approach VMX uses.
> 
> On a related note, there is no reason to limit the use of do_machine_check
> to 64 bit targets, as is currently done for VMX. MCE handling works
> for both target families.

...

> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 8959514eaf0f..01330096ff3e 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -4572,7 +4572,7 @@ static int handle_rmode_exception(struct kvm_vcpu *vcpu,
>   */
>  static void kvm_machine_check(void)
>  {
> -#if defined(CONFIG_X86_MCE) && defined(CONFIG_X86_64)
> +#if defined(CONFIG_X86_MCE)

This VMX change needs to be a separate patch, and it arguably warrants:

  Cc: stable@vger.kernel.org
  Fixes: a0861c02a981 ("KVM: Add VT-x machine check support")

>  	struct pt_regs regs = {
>  		.cs = 3, /* Fake ring 3 no matter what the guest ran on */
>  		.flags = X86_EFLAGS_IF,
> -- 
> 2.25.2
>