From: Marcelo Tosatti <mtosatti@redhat.com>
To: Avi Kivity <avi@qumranet.com>
Cc: Chris Wright <chrisw@redhat.com>, kvm-devel <kvm@vger.kernel.org>,
Len Brown <lenb@kernel.org>
Subject: Re: [patch 4/4] KVM: allow direct access to PMTimer port
Date: Sun, 25 May 2008 13:12:56 -0300 [thread overview]
Message-ID: <20080525161256.GB16012@dmt> (raw)
In-Reply-To: <48395C07.1050005@qumranet.com>
On Sun, May 25, 2008 at 03:31:03PM +0300, Avi Kivity wrote:
> Marcelo Tosatti wrote:
> >There's not much point in exiting for pmtimer reads, since it runs at a
> >fixed clock rate and its start value is undefined.
> >
>
> On a migration farm with lots of different hardware, eventually all
> guests will have migrated and none of them will be able to use the
> passthrough port.
>
> What about emulating pmtimer in the host kernel instead of userspace?
> It increases the hit from 1 exit to 3 exits, but they're much faster exits.
I agree, even began writing it, but I think the non-passthrough case
could be optimized later.
next prev parent reply other threads:[~2008-05-25 16:13 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-24 23:43 [patch 0/4] C2 "emulation" Marcelo Tosatti
2008-05-24 23:43 ` [patch 1/4] QEMU/KVM: self-disabling C2 emulation Marcelo Tosatti
2008-05-24 23:43 ` [patch 2/4] libkvm: KVM_GET_PMTIMER ioctl support Marcelo Tosatti
2008-05-24 23:43 ` [patch 3/4] QEMU/KVM: non-virtualized ACPI PMTimer support Marcelo Tosatti
2008-05-25 10:18 ` Avi Kivity
2008-05-25 16:32 ` Marcelo Tosatti
2008-05-26 8:16 ` Avi Kivity
2008-05-29 17:56 ` Marcelo Tosatti
2008-05-31 7:52 ` Avi Kivity
2008-05-25 10:19 ` Avi Kivity
2008-05-25 17:39 ` Marcelo Tosatti
2008-05-26 8:23 ` Avi Kivity
2008-05-24 23:43 ` [patch 4/4] KVM: allow direct access to PMTimer port Marcelo Tosatti
2008-05-25 10:04 ` Avi Kivity
2008-05-25 16:09 ` Marcelo Tosatti
2008-05-25 12:31 ` Avi Kivity
2008-05-25 16:12 ` Marcelo Tosatti [this message]
2008-05-26 8:03 ` Avi Kivity
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