linux-kernel - Re: [PATCH v6 5/5] x86/kvm: Avoid dynamic allocation of pvclock data when SEV is active

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Message-ID: <3b8b4c9c-b0f6-1e08-3d26-0e146cd7189e@redhat.com>
Date:   Tue, 11 Sep 2018 11:26:21 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Borislav Petkov <bp@...e.de>,
        Brijesh Singh <brijesh.singh@....com>,
        Sean Christopherson <sean.j.christopherson@...el.com>
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        Tom Lendacky <thomas.lendacky@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Radim Krčmář <rkrcmar@...hat.com>
Subject: Re: [PATCH v6 5/5] x86/kvm: Avoid dynamic allocation of pvclock data
 when SEV is active

On 10/09/2018 18:48, Borislav Petkov wrote:
> 
> so *maybe* - and I pretty much have no clue about virt - but just
> *maybe*, that kvmclock thing can be shared by all CPUs in a *guest*
> then. As in: the guest should see stable clocks which are the same
> regardless from which vCPU they're read and so on...

Usually the kvmclock structs are all the same, but there is support for
old machines with inconsistent TSCs (across different sockets typically).

Paolo