Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932183Ab3ILFmw (ORCPT ); Thu, 12 Sep 2013 01:42:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:24166 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753262Ab3ILFmu (ORCPT ); Thu, 12 Sep 2013 01:42:50 -0400 Date: Thu, 12 Sep 2013 08:44:53 +0300 From: "Michael S. Tsirkin" To: Raghavendra K T Cc: Gleb Natapov , Paolo Bonzini , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Rob Landley , mtosatti@redhat.com Subject: Re: [PATCH V2] Documentation/kvm: Update cpuid documentation for steal time and pv eoi Message-ID: <20130912054453.GA13116@redhat.com> References: <1378284526-863-1-git-send-email-raghavendra.kt@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1378284526-863-1-git-send-email-raghavendra.kt@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2908 Lines: 66 On Wed, Sep 04, 2013 at 02:18:46PM +0530, Raghavendra K T wrote: > Signed-off-by: Raghavendra K T > --- > Changes in V2: > Correction in the description of steal time and added msr info (Michael S Tsirkin) Thanks. Some comments below: > Documentation/virtual/kvm/cpuid.txt | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/Documentation/virtual/kvm/cpuid.txt b/Documentation/virtual/kvm/cpuid.txt > index 22ff659..6c4fb20 100644 > --- a/Documentation/virtual/kvm/cpuid.txt > +++ b/Documentation/virtual/kvm/cpuid.txt > @@ -43,6 +43,16 @@ KVM_FEATURE_CLOCKSOURCE2 || 3 || kvmclock available at msrs > KVM_FEATURE_ASYNC_PF || 4 || async pf can be enabled by > || || writing to msr 0x4b564d02 > ------------------------------------------------------------------------------ > +KVM_FEATURE_STEAL_TIME || 5 || Steal time available at msr > + || || 0x4b564d03. The feature is enabled > + || || by guest when host has schedstat > + || || or task delay accounting support. Well I think we really should be documenting the host/guest interface here. After all it starts out A guest running on a kvm host, can check some of its features using cpuid. And guests really should not try to guess whether host has schedstat or task delay accounting support based on this bit. So I would just say: "steal time can be enabled by writing to msr 0x4b564d02" just like async pf. > +------------------------------------------------------------------------------ > +KVM_FEATURE_PV_EOI || 6 || overrides the generic EOI > + || || implementation with a > + || || paravirtualized version. Available > + || || at msr 0x4b564d04. Actually there's no override: guest can still use the standard EOI even if PV EOI MSR is enabled. There's a detailed explanation of PV EOI in Documentation/virtual/kvm/msr.txt I think the following would be enough: "paravirtualized end of interrupt handler can be enabled by writing to msr 0x4b564d04" > +------------------------------------------------------------------------------ > KVM_FEATURE_PV_UNHALT || 7 || guest checks this feature bit > || || before enabling paravirtualized > || || spinlock support. > -- > 1.7.11.7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/