[1/6,v5,nVMX] : Check "load IA32_PAT" VM-exit control on vmentry
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Message ID 20190408213516.17966-2-krish.sadhukhan@oracle.com
State New
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  • [1/6,v5,nVMX] : Check "load IA32_PAT" VM-exit control on vmentry
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Commit Message

Krish Sadhukhan April 8, 2019, 9:35 p.m. UTC
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(+)

Comments

Paolo Bonzini April 10, 2019, 9:42 a.m. UTC | #1
On 08/04/19 23:35, 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..25aa4c4cf42a 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;
> +
>  	/*
>  	 * 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,
> 

I've sent a patch to optimize the check using bitwise operations.  Apart
from that, looks good.

Paolo

Patch
diff mbox series

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 3170e291215d..25aa4c4cf42a 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;
+
 	/*
 	 * 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,