Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754663Ab3ILHEc (ORCPT ); Thu, 12 Sep 2013 03:04:32 -0400 Received: from e28smtp04.in.ibm.com ([122.248.162.4]:45959 "EHLO e28smtp04.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753630Ab3ILHEb (ORCPT ); Thu, 12 Sep 2013 03:04:31 -0400 Message-ID: <523168E3.10405@linux.vnet.ibm.com> Date: Thu, 12 Sep 2013 12:40:27 +0530 From: Raghavendra K T Organization: IBM User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: "Michael S. Tsirkin" 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 References: <1378284526-863-1-git-send-email-raghavendra.kt@linux.vnet.ibm.com> <20130912054453.GA13116@redhat.com> In-Reply-To: <20130912054453.GA13116@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13091206-5564-0000-0000-000009AE9829 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1993 Lines: 48 On 09/12/2013 11:14 AM, Michael S. Tsirkin wrote: > On Wed, Sep 04, 2013 at 02:18:46PM +0530, Raghavendra K T wrote: [...] >> ------------------------------------------------------------------------------ >> +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. > It makes sense. will stick to the above line. > >> +------------------------------------------------------------------------------ >> +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" > Okay. Thanks Michael. -- 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/