Re: [PATCH V4 6/6] x86/hvm: pkeys, add pkeys support for cpuid handling

From: "Jan Beulich" <JBeulich@suse.com>
To: Huaitong Han <huaitong.han@intel.com>
Cc: kevin.tian@intel.com, wei.liu2@citrix.com,
	ian.campbell@citrix.com, stefano.stabellini@eu.citrix.com,
	george.dunlap@eu.citrix.com, andrew.cooper3@citrix.com,
	ian.jackson@eu.citrix.com, xen-devel@lists.xen.org,
	jun.nakajima@intel.com, keir@xen.org
Subject: Re: [PATCH V4 6/6] x86/hvm: pkeys, add pkeys support for cpuid handling
Date: Mon, 21 Dec 2015 08:07:42 -0700	[thread overview]
Message-ID: <567823CE02000078000C1F87@prv-mh.provo.novell.com> (raw)
In-Reply-To: <1450682504-32286-7-git-send-email-huaitong.han@intel.com>

>>> On 21.12.15 at 08:21, <huaitong.han@intel.com> wrote:
> @@ -4600,6 +4600,14 @@ void hvm_cpuid(unsigned int input, unsigned int *eax, unsigned int *ebx,
>          /* Don't expose INVPCID to non-hap hvm. */
>          if ( (count == 0) && !hap_enabled(d) )
>              *ebx &= ~cpufeat_mask(X86_FEATURE_INVPCID);
> +
> +        /* X86_FEATURE_PKU is not yet implemented for shadow paging. */
> +        if ( (count == 0) && !hap_enabled(d) )
> +            *ecx &= ~cpufeat_mask(X86_FEATURE_PKU);

I'm still missing the xsave dependency here.

> +        if ( (count == 0) && (*ecx & cpufeat_mask(X86_FEATURE_PKU)) )
> +            *ecx |= (v->arch.hvm_vcpu.guest_cr[4] & X86_CR4_PKE) ?
> +                     cpufeat_mask(X86_FEATURE_OSPKE) : 0;

Also all (would now be 6!) count == 0 dependencies should be
combined instead of repeating that condition so many times.

Jan