From: Joerg Roedel <joro@8bytes.org>
To: Zachary Amsden <zamsden@redhat.com>
Cc: kvm <kvm@vger.kernel.org>
Subject: Re: Fwd: [KVM TSC emulation 6/9] Allow adjust_tsc_offset to be in host or guest cycles
Date: Wed, 6 Jul 2011 12:00:11 +0200 [thread overview]
Message-ID: <20110706100010.GL29299@8bytes.org> (raw)
In-Reply-To: <4E008D05.8080705@redhat.com>
On Tue, Jun 21, 2011 at 05:22:29AM -0700, Zachary Amsden wrote:
> -static void svm_adjust_tsc_offset(struct kvm_vcpu *vcpu, s64 adjustment)
> +static void svm_adjust_tsc_offset(struct kvm_vcpu *vcpu, s64 adjustment, bool host)
> {
> struct vcpu_svm *svm = to_svm(vcpu);
>
> + WARN_ON(adjustment< 0);
> + if (host)
> + adjustment = svm_scale_tsc(vcpu, adjustment);
> +
This is not going to work out with tsc-scaling. The tsc-offset is
applied _after_ the hardware-tsc. Just scaling the offset with the same
factor will not give you the hardware tsc-value you expect.
Joerg
prev parent reply other threads:[~2011-07-06 10:00 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-21 12:22 Fwd: [KVM TSC emulation 6/9] Allow adjust_tsc_offset to be in host or guest cycles Zachary Amsden
2011-07-06 10:00 ` Joerg Roedel [this message]
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