diff mbox series

[v2,4/7] KVM:CPUID: Fix xsaves area size calculation for CPUID.(EAX=0xD,ECX=1).

Message ID 20190122205909.24165-5-weijiang.yang@intel.com (mailing list archive)
State New, archived
Headers show
Series This patch-set is to enable Guest CET support | expand

Commit Message

Yang, Weijiang Jan. 22, 2019, 8:59 p.m. UTC 
According to latest Software Development Manual vol.2/3.2,
for CPUID.(EAX=0xD,ECX=1), it should report xsaves area size
containing all states enabled  by XCR0|IA32_MSR_XSS.

Signed-off-by: Zhang Yi Z <yi.z.zhang@linux.intel.com>
Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
---
 arch/x86/kvm/cpuid.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Sean Christopherson Jan. 25, 2019, 10:47 p.m. UTC | #1 
On Wed, Jan 23, 2019 at 04:59:06AM +0800, Yang Weijiang wrote:
> According to latest Software Development Manual vol.2/3.2,
> for CPUID.(EAX=0xD,ECX=1), it should report xsaves area size
> containing all states enabled  by XCR0|IA32_MSR_XSS.
> 
> Signed-off-by: Zhang Yi Z <yi.z.zhang@linux.intel.com>
> Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
> ---
>  arch/x86/kvm/cpuid.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index dbeb4e7904eb..67b464d1d749 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -136,7 +136,8 @@ int kvm_update_cpuid(struct kvm_vcpu *vcpu)
>  
>  	best = kvm_find_cpuid_entry(vcpu, 0xD, 1);
>  	if (best && (best->eax & (F(XSAVES) | F(XSAVEC))))
> -		best->ebx = xstate_required_size(vcpu->arch.xcr0, true);
> +		best->ebx = xstate_required_size(vcpu->arch.xcr0 |
> +			    kvm_supported_xss(), true);

kvm_supported_xss() provides the wrong value, that's what's *supported*.
CPUID reflects what's actually enabled, e.g. vcpu->arch.ia32_xss.

If you're going to bother adding spaces to align things, might as well
align the parameters, e.g.:

		best->ebx = xstate_required_size(vcpu->arch.xcr0 |
						 vcpu->arch.ia32_xss, true);

>  
>  	/*
>  	 * The existing code assumes virtual address is 48-bit or 57-bit in the
> -- 
> 2.17.1
>
diff mbox series

Patch

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index dbeb4e7904eb..67b464d1d749 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -136,7 +136,8 @@  int kvm_update_cpuid(struct kvm_vcpu *vcpu)
 
 	best = kvm_find_cpuid_entry(vcpu, 0xD, 1);
 	if (best && (best->eax & (F(XSAVES) | F(XSAVEC))))
-		best->ebx = xstate_required_size(vcpu->arch.xcr0, true);
+		best->ebx = xstate_required_size(vcpu->arch.xcr0 |
+			    kvm_supported_xss(), true);
 
 	/*
 	 * The existing code assumes virtual address is 48-bit or 57-bit in the