From mboxrd@z Thu Jan  1 00:00:00 1970
From: Joerg Roedel <joro@8bytes.org>
Subject: Re: [PATCH 3/6] KVM: X86: Make tsc_delta calculation a function of
	guest tsc
Date: Sun, 17 Apr 2011 14:06:56 +0200
Message-ID: <20110417120656.GT18463@8bytes.org>
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Cc: Joerg Roedel <joerg.roedel@amd.com>, Avi Kivity <avi@redhat.com>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	Zachary Amsden <zamsden@redhat.com>, kvm@vger.kernel.org
To: Jan Kiszka <jan.kiszka@web.de>
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On Sat, Apr 16, 2011 at 06:09:17PM +0200, Jan Kiszka wrote:
> On 2011-03-25 09:44, Joerg Roedel wrote:

> > +		tsc_delta = !vcpu->arch.last_guest_tsc ? 0 :
> > +			     tsc - vcpu->arch.last_guest_tsc;

> This patch appears to cause troubles to Linux guests on TSC clocksource
> and APIC highres timer. The first boot after qemu start is always fine,
> but after a reboot the guest timer appears to fire incorrectly or even
> not at all.
> 
> Was this patch tested with a guest reboot scenario as well? Does it
> account for the TSC being reset to 0 on reboot?

Hmm, probably the last_guest_tsc is not updated correctly in this
scenario. I will have a look tomorrow.

	Joerg