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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20200228002833.GB30452@linux.intel.com>
Date:   Thu, 27 Feb 2020 16:28:33 -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 Tue, Feb 25, 2020 at 04:10:18PM +0100, Paolo Bonzini wrote:
> On 01/02/20 19:51, Sean Christopherson wrote:
> > +	/* CPUID 0x8000000A */
> > +	/* Support next_rip if host supports it */
> > +	if (boot_cpu_has(X86_FEATURE_NRIPS))
> > +		kvm_cpu_cap_set(X86_FEATURE_NRIPS);
> 
> Should this also be conditional on "nested"?

I think that makes sense?  AFAICT it should probably be conditional on
"nrips" as well.  X86_FEATURE_NPT should also be conditional on "nested".
I'll tack on a patch to make those changes, the cleanup is easier without
the things spread across different case statements, e.g. wrap the entire
SVM feature leaf in "if (nested)".