Re: [PATCH 1/6 v4][KVM nVMX]: Check "load IA32_PAT" VM-exit control on vmentry

From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Cc: kvm@vger.kernel.org, pbonzini@redhat.com, rkrcmar@redhat.com,
	jmattson@google.com
Subject: Re: [PATCH 1/6 v4][KVM nVMX]: Check "load IA32_PAT" VM-exit control on vmentry
Date: Mon, 8 Apr 2019 10:21:05 -0700	[thread overview]
Message-ID: <20190408172105.GF25880@linux.intel.com> (raw)
In-Reply-To: <20190405014650.16880-2-krish.sadhukhan@oracle.com>

On Thu, Apr 04, 2019 at 09:46:45PM -0400, Krish Sadhukhan wrote:
> According to section "Checks on Host Control Registers and MSRs" in Intel
> SDM vol 3C, the following check is performed on vmentry:
> 
>     If the "load IA32_PAT" VM-exit control is 1, the value of the field
>     for the IA32_PAT MSR must be one that could be written by WRMSR
>     without fault at CPL 0. Specifically, each of the 8 bytes in the
>     field must have one of the values 0 (UC), 1 (WC), 4 (WT), 5 (WP),
>     6 (WB), or 7 (UC-).
> 
> Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
> Reviewed-by: Karl Heubaum <karl.heubaum@oracle.com>
> Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Reviewed-by: Jim Mattson <jmattson@google.com>
> ---
>  arch/x86/kvm/vmx/nested.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index 3170e291215d..f601b156ca84 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -2595,6 +2595,11 @@ static int nested_check_host_control_regs(struct kvm_vcpu *vcpu,
>  	    !nested_host_cr4_valid(vcpu, vmcs12->host_cr4) ||
>  	    !nested_cr3_valid(vcpu, vmcs12->host_cr3))
>  		return -EINVAL;
> +
> +	if ((vmcs12->vm_exit_controls & VM_EXIT_LOAD_IA32_PAT) &&
> +	    !kvm_mtrr_valid(vcpu, MSR_IA32_CR_PAT, vmcs12->host_ia32_pat))
> +			return -EINVAL;

Doh, "return -EINVAL" is indented too far, only noticed it now because
this conflicts with the latest kvm/queue.  Paolo/Radim can likely fix it
up while applying since they'll need to deal with the conflict anyways.

> +
>  	/*
>  	 * If the load IA32_EFER VM-exit control is 1, bits reserved in the
>  	 * IA32_EFER MSR must be 0 in the field for that register. In addition,
> -- 
> 2.17.2
> 