linux-kernel - Re: [PATCH v2 3/7] KVM:CPUID: Add CPUID support for CET xsaves component query.

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Message-ID: <249c8543-4b87-8fd2-2e1d-68b72ee62c61@redhat.com>
Date:   Fri, 25 Jan 2019 18:57:10 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Yang Weijiang <weijiang.yang@...el.com>, rkrcmar@...hat.com,
        sean.j.christopherson@...el.com, jmattson@...gle.com,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org, mst@...hat.com,
        yu-cheng.yu@...el.com, yi.z.zhang@...el.com, hjl.tools@...il.com
Cc:     Zhang Yi Z <yi.z.zhang@...ux.intel.com>
Subject: Re: [PATCH v2 3/7] KVM:CPUID: Add CPUID support for CET xsaves
 component query.

On 22/01/19 21:59, Yang Weijiang wrote:
>  			 */
>  			entry->edx |= F(ARCH_CAPABILITIES);
> +			/*
> +			 * If host doesn't have CET capability,
> +			 * do not report CET related info.
> +			 */
> +			if (!boot_cpu_has(X86_FEATURE_SHSTK))
> +				entry->ecx &= ~F(SHSTK);
> +
> +			if (!boot_cpu_has(X86_FEATURE_IBT))
> +				entry->edx &= ~F(IBT);
> +

This is not needed, it is implied by

                        cpuid_mask(&entry->ecx, CPUID_7_ECX);
                        cpuid_mask(&entry->edx, CPUID_7_EDX);

earlier in the function.

Paolo