diff mbox series

[v6,15/25] KVM: x86: Add fault checks for guest CR4.CET setting

Message ID 20230914063325.85503-16-weijiang.yang@intel.com (mailing list archive)
State New, archived
Headers show
Series Enable CET Virtualization | expand

Commit Message

Yang, Weijiang Sept. 14, 2023, 6:33 a.m. UTC 
Check potential faults for CR4.CET setting per Intel SDM requirements.
CET can be enabled if and only if CR0.WP == 1, i.e. setting CR4.CET ==
1 faults if CR0.WP == 0 and setting CR0.WP == 0 fails if CR4.CET == 1.

Reviewed-by: Chao Gao <chao.gao@intel.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
---
 arch/x86/kvm/x86.c | 6 ++++++
 1 file changed, 6 insertions(+)

Comments

Maxim Levitsky Oct. 31, 2023, 5:51 p.m. UTC | #1 
On Thu, 2023-09-14 at 02:33 -0400, Yang Weijiang wrote:
> Check potential faults for CR4.CET setting per Intel SDM requirements.
> CET can be enabled if and only if CR0.WP == 1, i.e. setting CR4.CET ==
> 1 faults if CR0.WP == 0 and setting CR0.WP == 0 fails if CR4.CET == 1.
> 
> Reviewed-by: Chao Gao <chao.gao@intel.com>
> Co-developed-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
> ---
>  arch/x86/kvm/x86.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index a091764bf1d2..dda9c7141ea1 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -1006,6 +1006,9 @@ int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
>  	    (is_64_bit_mode(vcpu) || kvm_is_cr4_bit_set(vcpu, X86_CR4_PCIDE)))
>  		return 1;
>  
> +	if (!(cr0 & X86_CR0_WP) && kvm_is_cr4_bit_set(vcpu, X86_CR4_CET))
> +		return 1;
> +
>  	static_call(kvm_x86_set_cr0)(vcpu, cr0);
>  
>  	kvm_post_set_cr0(vcpu, old_cr0, cr0);
> @@ -1217,6 +1220,9 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
>  			return 1;
>  	}
>  
> +	if ((cr4 & X86_CR4_CET) && !kvm_is_cr0_bit_set(vcpu, X86_CR0_WP))
> +		return 1;
> +
>  	static_call(kvm_x86_set_cr4)(vcpu, cr4);
>  
>  	kvm_post_set_cr4(vcpu, old_cr4, cr4);

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>

Best regards,
	Maxim Levitsky
diff mbox series

Patch

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a091764bf1d2..dda9c7141ea1 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1006,6 +1006,9 @@  int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
 	    (is_64_bit_mode(vcpu) || kvm_is_cr4_bit_set(vcpu, X86_CR4_PCIDE)))
 		return 1;
 
+	if (!(cr0 & X86_CR0_WP) && kvm_is_cr4_bit_set(vcpu, X86_CR4_CET))
+		return 1;
+
 	static_call(kvm_x86_set_cr0)(vcpu, cr0);
 
 	kvm_post_set_cr0(vcpu, old_cr0, cr0);
@@ -1217,6 +1220,9 @@  int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
 			return 1;
 	}
 
+	if ((cr4 & X86_CR4_CET) && !kvm_is_cr0_bit_set(vcpu, X86_CR0_WP))
+		return 1;
+
 	static_call(kvm_x86_set_cr4)(vcpu, cr4);
 
 	kvm_post_set_cr4(vcpu, old_cr4, cr4);