linux-kernel - Re: [PATCH 09/10] KVM: x86: Setup Hyper-V TSC page before Xen PV clocks (during clock update)

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: <eb45ff29-f551-483e-9930-1fa545fb83aa@xen.org>
Date: Tue, 21 Jan 2025 15:59:29 +0000
From: Paul Durrant <xadimgnik@...il.com>
To: Sean Christopherson <seanjc@...gle.com>,
 Vitaly Kuznetsov <vkuznets@...hat.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>, David Woodhouse
 <dwmw2@...radead.org>, kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
 syzbot+352e553a86e0d75f5120@...kaller.appspotmail.com,
 Paul Durrant <pdurrant@...zon.com>, David Woodhouse <dwmw@...zon.co.uk>
Subject: Re: [PATCH 09/10] KVM: x86: Setup Hyper-V TSC page before Xen PV
 clocks (during clock update)

On 21/01/2025 15:44, Sean Christopherson wrote:
[snip]
> 
> I think it's ok to keep the Hyper-V TSC page in this case.  It's not that the Xen
> PV clock is truly unstable, it's that some guests get tripped up by the STABLE
> flag.  A guest that can't handle the STABLE flag has bigger problems than the
> existence of a completely unrelated clock that is implied to be stable.
> 

Agreed.

>> I don't know if anyone combines Xen and Hyper-V emulation capabilities for
>> the same guest on KVM though.)
> 
> That someone would have to be quite "brave" :-D

Maybe :-)

Reviewed-by: Paul Durrant <paul@....org>