From: Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org>
To: Rusty Russell <rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>
Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Subject: Re: Paravirt KVM capabilities
Date: Thu, 11 Jan 2007 01:49:57 +0100 [thread overview]
Message-ID: <20070111004957.GA3279@elte.hu> (raw)
In-Reply-To: <1168476120.19646.209.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
* Rusty Russell <rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org> wrote:
> > > - cr3 switches for CONFIG_PARAVIRT syscalls (which are necessary
> > > on x86_64) will probably become very cheap with tagged tlbs
> >
> > but irq overhead is nothing in importance compared to basic syscall
> > overhead. KVM/HVM already runs guest kernel syscalls at native
> > speed. KVM/LL (or Xen) has to switch cr3s to enter guest kernel
> > context
>
> Err no, this isn't true. See Documentation/lhype.txt or various blog
> entries on the subject 8) Both Xen and lhype get native syscall speeds
> (within measurement error).
i was talking about 64-bit. (we dont really design for 32-bit anymore.)
I know that lhype uses Xen's ring 1 trick, but that's a 32-bit-only
thing. Also, can SYSENTER trap from guest userspace ring 3 into guest
kernelspace ring 1 on lhype?
Ingo
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next prev parent reply other threads:[~2007-01-11 0:49 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-09 14:19 Paravirt KVM capabilities Hugo Mills
[not found] ` <20070109141916.GA13276-qdzjUQGjHNdnxAzMjxVBUbVCufUGDwFn@public.gmane.org>
2007-01-09 14:27 ` Avi Kivity
[not found] ` <45A3A642.1030604-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-01-09 23:20 ` Rusty Russell
[not found] ` <1168384852.19646.161.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2007-01-10 9:47 ` Ingo Molnar
[not found] ` <20070110094750.GA934-X9Un+BFzKDI@public.gmane.org>
2007-01-10 10:09 ` Ulrich Drepper
[not found] ` <45A4BB74.9010102-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2007-01-10 10:18 ` Ingo Molnar
[not found] ` <20070110101839.GA6444-X9Un+BFzKDI@public.gmane.org>
2007-01-10 10:43 ` Avi Kivity
[not found] ` <45A4C345.5050404-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-01-10 10:52 ` Ingo Molnar
[not found] ` <20070110105202.GA13412-X9Un+BFzKDI@public.gmane.org>
2007-01-10 11:03 ` Avi Kivity
[not found] ` <45A4C7ED.8090003-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-01-10 11:14 ` Ingo Molnar
[not found] ` <20070110111442.GA16867-X9Un+BFzKDI@public.gmane.org>
2007-01-10 11:42 ` Avi Kivity
2007-01-10 18:00 ` Ulrich Drepper
[not found] ` <45A529DB.4030009-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2007-01-10 18:12 ` Avi Kivity
[not found] ` <45A52C8B.70608-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
2007-01-10 18:27 ` Ulrich Drepper
[not found] ` <45A53005.30300-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2007-01-10 18:35 ` Avi Kivity
2007-01-10 17:00 ` Anthony Liguori
[not found] ` <45A51BA2.9090005-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
2007-01-10 17:23 ` Avi Kivity
2007-01-11 0:42 ` Rusty Russell
[not found] ` <1168476120.19646.209.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2007-01-11 0:49 ` Ingo Molnar [this message]
[not found] ` <20070111004957.GA3279-X9Un+BFzKDI@public.gmane.org>
2007-01-11 2:39 ` Rusty Russell
[not found] ` <1168483188.19646.241.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2007-01-11 2:51 ` Ingo Molnar
[not found] ` <20070111025130.GB21368-X9Un+BFzKDI@public.gmane.org>
2007-01-11 3:21 ` Rusty Russell
[not found] ` <1168485696.19646.250.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2007-01-11 9:38 ` Ingo Molnar
2007-01-10 10:46 ` Rusty Russell
[not found] ` <1168425985.19646.205.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2007-01-10 11:00 ` sean-cz32UWRuVxBIf6P1QZMOBw
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