linux-kernel - Re: [PATCH v11 3/9] KVM: VMX: Set host/guest CET states for vmexit/vmentry

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Message-ID: <20200427170426.GH14870@linux.intel.com>
Date:   Mon, 27 Apr 2020 10:04:26 -0700
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Yang Weijiang <weijiang.yang@...el.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        pbonzini@...hat.com, jmattson@...gle.com,
        yu.c.zhang@...ux.intel.com
Subject: Re: [PATCH v11 3/9] KVM: VMX: Set host/guest CET states for
 vmexit/vmentry

On Sat, Apr 25, 2020 at 05:20:21PM +0800, Yang Weijiang wrote:
> On Fri, Apr 24, 2020 at 07:49:41AM -0700, Sean Christopherson wrote:
> > On Fri, Apr 24, 2020 at 10:35:10PM +0800, Yang Weijiang wrote:
> > > On Thu, Apr 23, 2020 at 10:17:41AM -0700, Sean Christopherson wrote:
> > > > On Thu, Mar 26, 2020 at 04:18:40PM +0800, Yang Weijiang wrote:
> > > > > @@ -7140,8 +7175,23 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
> > > > >  	}
> > > > >  
> > > > >  	if (guest_cpuid_has(vcpu, X86_FEATURE_SHSTK) ||
> > > > > -	    guest_cpuid_has(vcpu, X86_FEATURE_IBT))
> > > > > +	    guest_cpuid_has(vcpu, X86_FEATURE_IBT)) {
> > > > >  		vmx_update_intercept_for_cet_msr(vcpu);
> > > > > +
> > > > > +		if (cpu_has_cet_guest_load_ctrl() && is_cet_supported(vcpu))
> > > > > +			vm_entry_controls_setbit(to_vmx(vcpu),
> > > > > +						 VM_ENTRY_LOAD_GUEST_CET_STATE);
> > > > > +		else
> > > > > +			vm_entry_controls_clearbit(to_vmx(vcpu),
> > > > > +						   VM_ENTRY_LOAD_GUEST_CET_STATE);
> > > > > +
> > > > > +		if (cpu_has_cet_host_load_ctrl() && is_cet_supported(vcpu))
> > > > > +			vm_exit_controls_setbit(to_vmx(vcpu),
> > > > > +						VM_EXIT_LOAD_HOST_CET_STATE);
> > > > > +		else
> > > > > +			vm_exit_controls_clearbit(to_vmx(vcpu),
> > > > > +						  VM_EXIT_LOAD_HOST_CET_STATE);
> > > > 
> > > > As above, I think this can be done in vmx_set_cr4().
> > > >
> > > Hmm, it's in vmx_set_cr4() in early versions, OK, will move them back.
> > 
> > Did I advise you to move them out of vmx_set_cr4()?  It's entirely possible
> > I forgot some detail since the last time I reviewed this series.
> Things are always changing, I'm willing to change any part of the patch
> before it's landed :-).

I'm worried that there was a reason for requesting the logic to be moved
out vmx_set_cr4() that I've since forgotten.  I'll see if I can dredge up
the old mail.