Date:   Sun, 12 Dec 2021 21:10:59 +0800
From:   Yang Zhong <yang.zhong@intel.com>
To:     Paolo Bonzini <pbonzini@redhat.com>
Cc:     x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
        tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
        dave.hansen@linux.intel.com, seanjc@google.com,
        jun.nakajima@intel.com, kevin.tian@intel.com,
        jing2.liu@linux.intel.com, jing2.liu@intel.com,
        yang.zhong@intel.com
Subject: Re: [PATCH 15/19] kvm: x86: Save and restore guest XFD_ERR properly
Message-ID: <20211212131059.GA21846@yangzhon-Virtual>
References: <20211208000359.2853257-1-yang.zhong@intel.com>
 <20211208000359.2853257-16-yang.zhong@intel.com>
 <97814bdf-2e58-2823-ca55-30b2447af3f1@redhat.com>
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In-Reply-To: <97814bdf-2e58-2823-ca55-30b2447af3f1@redhat.com>
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On Fri, Dec 10, 2021 at 11:01:15PM +0100, Paolo Bonzini wrote:
> On 12/8/21 01:03, Yang Zhong wrote:
> >--- a/arch/x86/kvm/cpuid.c
> >+++ b/arch/x86/kvm/cpuid.c
> >@@ -219,6 +219,11 @@ static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
> >  		kvm_apic_set_version(vcpu);
> >  	}
> >+	/* Enable saving guest XFD_ERR */
> >+	best = kvm_find_cpuid_entry(vcpu, 7, 0);
> >+	if (best && cpuid_entry_has(best, X86_FEATURE_AMX_TILE))
> >+		vcpu->arch.guest_fpu.xfd_err = 0;
> >+
> 
> This is incorrect.  Instead it should check whether leaf 0xD
> includes any dynamic features.
> 

  Thanks Paolo, So ditto for "[PATCH 04/19] kvm: x86: Check guest xstate permissions when KVM_SET_CPUID2".

  Yang

> Paolo