linux-kernel - Re: [PATCH 39/61] KVM: SVM: Convert feature updates from CPUID to KVM cpu caps

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Message-ID: <20200228150914.GB2329@linux.intel.com>
Date:   Fri, 28 Feb 2020 07:09:14 -0800
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 39/61] KVM: SVM: Convert feature updates from CPUID to
 KVM cpu caps

On Fri, Feb 28, 2020 at 08:03:33AM +0100, Paolo Bonzini wrote:
> On 28/02/20 01:36, Sean Christopherson wrote:
> > Regarding NRIPS, the original commit added the "Support next_rip if host
> > supports it" comment, but I can't tell is "host supports" means "supported
> > in hardware" or "supported by KVM".  In other words, should I make the cap
> > dependent "nrips" or leave it as is?
> > 
> 
> The "nrips" parameter came later.  For VMX we generally remove guest
> capabilities if the corresponding parameter is on, so it's a good idea
> to do the same for SVM.

Huh.  I swear I looked at the code from the original commit and saw nrips
there, but it was clearly added in 2019 via commit d647eb63e671 ("KVM: svm:
add nrips module parameter").