linux-kernel - Re: [PATCH] KVM: VMX: Do not trap VMFUNC instructions for L1 guests.

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Date:   Tue, 8 Nov 2022 18:23:57 +0800
From:   Yu Zhang <yu.c.zhang@...ux.intel.com>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] KVM: VMX: Do not trap VMFUNC instructions for L1 guests.

On Mon, Nov 07, 2022 at 05:36:21PM +0000, Sean Christopherson wrote:
> On Mon, Nov 07, 2022, Paolo Bonzini wrote:
> > On 11/7/22 09:27, Yu Zhang wrote:
> > > VMFUNC is not supported for L1 guests, and executing VMFUNC in
> > > L1 shall generate a #UD directly. Just disable it in secondary
> > > proc-based execution control for L1, instead of intercepting it
> > > and inject the #UD again.
> > > 
> > > Signed-off-by: Yu Zhang<yu.c.zhang@...ux.intel.com>
> > 
> > Is this for TDX or similar?  The reason for a patch should be mentioned in
> > the commit message.
> 
> It's just a cleanup, but (a) it should be split over two patches as disabling
> VMFUNC for L1 is technically a functional change, where as the changes to
> nested_vmx_setup_ctls_msrs() are pure cleanups, and (b) the !guest_mode path in
> handle_vmfunc() should either be removed or turned into a KVM_BUG_ON().
> 

Got it. Will do in V2. And thanks!

B.R.
Yu