linux-kernel - Re: [PATCH v11 2/9] KVM: VMX: Set guest CET MSRs per KVM and host configuration

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Message-ID: <20200426152600.GC29493@local-michael-cet-test.sh.intel.com>
Date:   Sun, 26 Apr 2020 23:26:01 +0800
From:   Yang Weijiang <weijiang.yang@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Yang Weijiang <weijiang.yang@...el.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, jmattson@...gle.com,
        yu.c.zhang@...ux.intel.com
Subject: Re: [PATCH v11 2/9] KVM: VMX: Set guest CET MSRs per KVM and host
 configuration

On Sat, Apr 25, 2020 at 03:26:30PM +0200, Paolo Bonzini wrote:
> On 23/04/20 18:27, Sean Christopherson wrote:
> >>  
> >> +static bool is_cet_mode_allowed(struct kvm_vcpu *vcpu, u32 mode_mask)
> > CET itself isn't a mode.  And since this ends up being an inner helper for
> > is_cet_supported(), I think __is_cet_supported() would be the way to go.
> > 
> > Even @mode_mask is a bit confusing without the context of it being kernel
> > vs. user.  The callers are very readable, e.g. I'd much prefer passing the
> > mask as opposed to doing 'bool kernel'.  Maybe s/mode_mask/cet_mask?  That
> > doesn't exactly make things super clear, but at least the reader knows the
> > mask is for CET features.
> 
> What about is_cet_state_supported and xss_states?
>
It's good for me, I'll change them accordingly, thank you for review!

> Paolo
> 
> >> +{
> >> +	return ((supported_xss & mode_mask) &&
> >> +		(guest_cpuid_has(vcpu, X86_FEATURE_SHSTK) ||
> >> +		guest_cpuid_has(vcpu, X86_FEATURE_IBT)));
> >> +}