linux-kernel - Re: [PATCH v14 07/13] KVM: VMX: Emulate reads and writes to CET MSRs

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Date:   Fri, 29 Jan 2021 16:07:19 +0800
From:   Yang Weijiang <weijiang.yang@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Yang Weijiang <weijiang.yang@...el.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, sean.j.christopherson@...el.com,
        jmattson@...gle.com, yu.c.zhang@...ux.intel.com
Subject: Re: [PATCH v14 07/13] KVM: VMX: Emulate reads and writes to CET MSRs

On Thu, Jan 28, 2021 at 06:45:08PM +0100, Paolo Bonzini wrote:
> On 06/11/20 02:16, Yang Weijiang wrote:
> > 
> > +static bool cet_is_ssp_msr_accessible(struct kvm_vcpu *vcpu,
> > +				      struct msr_data *msr)
> > +{
> > +	u64 mask;
> > +
> > +	if (!kvm_cet_supported())
> > +		return false;
> > +
> > +	if (msr->host_initiated)
> > +		return true;
> > +
> > +	if (!guest_cpuid_has(vcpu, X86_FEATURE_SHSTK))
> > +		return false;
> > +
> > +	if (msr->index == MSR_IA32_INT_SSP_TAB)
> > +		return false;
> 
> Shouldn't this return true?
>
Hi, Paolo,
Thanks for the feedback!
Yes, it should be true, will fix it in next release.
> Paolo
> 
> > +	mask = (msr->index == MSR_IA32_PL3_SSP) ? XFEATURE_MASK_CET_USER :
> > +						  XFEATURE_MASK_CET_KERNEL;
> > +	return !!(vcpu->arch.guest_supported_xss & mask);
> > +}