From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760036Ab3FDHSL (ORCPT ); Tue, 4 Jun 2013 03:18:11 -0400 Received: from e23smtp07.au.ibm.com ([202.81.31.140]:52791 "EHLO e23smtp07.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759665Ab3FDHSI (ORCPT ); Tue, 4 Jun 2013 03:18:08 -0400 Message-ID: <51AD95A2.2070906@linux.vnet.ibm.com> Date: Tue, 04 Jun 2013 12:52:10 +0530 From: Raghavendra K T Organization: IBM User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:16.0) Gecko/20121029 Thunderbird/16.0.2 MIME-Version: 1.0 To: Konrad Rzeszutek Wilk CC: gleb@redhat.com, mingo@redhat.com, jeremy@goop.org, x86@kernel.org, hpa@zytor.com, pbonzini@redhat.com, linux-doc@vger.kernel.org, habanero@linux.vnet.ibm.com, xen-devel@lists.xensource.com, peterz@infradead.org, mtosatti@redhat.com, stefano.stabellini@eu.citrix.com, andi@firstfloor.org, attilio.rao@citrix.com, ouyang@cs.pitt.edu, gregkh@suse.de, agraf@suse.de, chegu_vinod@hp.com, torvalds@linux-foundation.org, avi.kivity@gmail.com, tglx@linutronix.de, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, stephan.diestelhorst@amd.com, riel@redhat.com, drjones@redhat.com, virtualization@lists.linux-foundation.org, srivatsa.vaddagiri@gmail.com Subject: Re: [PATCH RFC V9 18/19] Documentation/kvm : Add documentation on Hypercalls and features used for PV spinlock References: <20130601192125.5966.35563.sendpatchset@codeblue> <20130601192624.5966.97025.sendpatchset@codeblue> <20130603160416.GH4224@phenom.dumpdata.com> In-Reply-To: <20130603160416.GH4224@phenom.dumpdata.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13060407-0260-0000-0000-000003194447 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/03/2013 09:34 PM, Konrad Rzeszutek Wilk wrote: > On Sun, Jun 02, 2013 at 12:56:24AM +0530, Raghavendra K T wrote: >> Documentation/kvm : Add documentation on Hypercalls and features used for PV spinlock >> >> From: Raghavendra K T >> >> KVM_HC_KICK_CPU hypercall added to wakeup halted vcpu in paravirtual spinlock >> enabled guest. >> >> KVM_FEATURE_PV_UNHALT enables guest to check whether pv spinlock can be enabled >> in guest. >> >> Thanks Vatsa for rewriting KVM_HC_KICK_CPU >> >> Signed-off-by: Srivatsa Vaddagiri >> Signed-off-by: Raghavendra K T >> --- >> Documentation/virtual/kvm/cpuid.txt | 4 ++++ >> Documentation/virtual/kvm/hypercalls.txt | 13 +++++++++++++ >> 2 files changed, 17 insertions(+) >> >> diff --git a/Documentation/virtual/kvm/cpuid.txt b/Documentation/virtual/kvm/cpuid.txt >> index 83afe65..654f43c 100644 >> --- a/Documentation/virtual/kvm/cpuid.txt >> +++ b/Documentation/virtual/kvm/cpuid.txt >> @@ -43,6 +43,10 @@ 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_PV_UNHALT || 6 || guest checks this feature bit >> + || || before enabling paravirtualized >> + || || spinlock support. >> +------------------------------------------------------------------------------ >> KVM_FEATURE_CLOCKSOURCE_STABLE_BIT || 24 || host will warn if no guest-side >> || || per-cpu warps are expected in >> || || kvmclock. >> diff --git a/Documentation/virtual/kvm/hypercalls.txt b/Documentation/virtual/kvm/hypercalls.txt >> index ea113b5..2a4da11 100644 >> --- a/Documentation/virtual/kvm/hypercalls.txt >> +++ b/Documentation/virtual/kvm/hypercalls.txt >> @@ -64,3 +64,16 @@ Purpose: To enable communication between the hypervisor and guest there is a >> shared page that contains parts of supervisor visible register state. >> The guest can map this shared page to access its supervisor register through >> memory using this hypercall. >> + >> +5. KVM_HC_KICK_CPU >> +------------------------ >> +Architecture: x86 >> +Status: active >> +Purpose: Hypercall used to wakeup a vcpu from HLT state >> +Usage example : A vcpu of a paravirtualized guest that is busywaiting in guest >> +kernel mode for an event to occur (ex: a spinlock to become available) can >> +execute HLT instruction once it has busy-waited for more than a threshold >> +time-interval. Execution of HLT instruction would cause the hypervisor to put >> +the vcpu to sleep until occurence of an appropriate event. Another vcpu of the >> +same guest can wakeup the sleeping vcpu by issuing KVM_HC_KICK_CPU hypercall, >> +specifying APIC ID of the vcpu to be wokenup. > > woken up. Yep. :) From mboxrd@z Thu Jan 1 00:00:00 1970 From: Raghavendra K T Subject: Re: [PATCH RFC V9 18/19] Documentation/kvm : Add documentation on Hypercalls and features used for PV spinlock Date: Tue, 04 Jun 2013 12:52:10 +0530 Message-ID: <51AD95A2.2070906@linux.vnet.ibm.com> References: <20130601192125.5966.35563.sendpatchset@codeblue> <20130601192624.5966.97025.sendpatchset@codeblue> <20130603160416.GH4224@phenom.dumpdata.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Cc: jeremy@goop.org, gregkh@suse.de, kvm@vger.kernel.org, linux-doc@vger.kernel.org, peterz@infradead.org, drjones@redhat.com, virtualization@lists.linux-foundation.org, andi@firstfloor.org, hpa@zytor.com, xen-devel@lists.xensource.com, x86@kernel.org, mingo@redhat.com, habanero@linux.vnet.ibm.com, riel@redhat.com, stefano.stabellini@eu.citrix.com, ouyang@cs.pitt.edu, avi.kivity@gmail.com, tglx@linutronix.de, chegu_vinod@hp.com, linux-kernel@vger.kernel.org, srivatsa.vaddagiri@gmail.com, attilio.rao@citrix.com, pbonzini@redhat.com, torvalds@linux-foundation.org, stephan.diestelhorst@amd.com To: Konrad Rzeszutek Wilk Return-path: In-Reply-To: <20130603160416.GH4224@phenom.dumpdata.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org List-Id: kvm.vger.kernel.org On 06/03/2013 09:34 PM, Konrad Rzeszutek Wilk wrote: > On Sun, Jun 02, 2013 at 12:56:24AM +0530, Raghavendra K T wrote: >> Documentation/kvm : Add documentation on Hypercalls and features used for PV spinlock >> >> From: Raghavendra K T >> >> KVM_HC_KICK_CPU hypercall added to wakeup halted vcpu in paravirtual spinlock >> enabled guest. >> >> KVM_FEATURE_PV_UNHALT enables guest to check whether pv spinlock can be enabled >> in guest. >> >> Thanks Vatsa for rewriting KVM_HC_KICK_CPU >> >> Signed-off-by: Srivatsa Vaddagiri >> Signed-off-by: Raghavendra K T >> --- >> Documentation/virtual/kvm/cpuid.txt | 4 ++++ >> Documentation/virtual/kvm/hypercalls.txt | 13 +++++++++++++ >> 2 files changed, 17 insertions(+) >> >> diff --git a/Documentation/virtual/kvm/cpuid.txt b/Documentation/virtual/kvm/cpuid.txt >> index 83afe65..654f43c 100644 >> --- a/Documentation/virtual/kvm/cpuid.txt >> +++ b/Documentation/virtual/kvm/cpuid.txt >> @@ -43,6 +43,10 @@ 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_PV_UNHALT || 6 || guest checks this feature bit >> + || || before enabling paravirtualized >> + || || spinlock support. >> +------------------------------------------------------------------------------ >> KVM_FEATURE_CLOCKSOURCE_STABLE_BIT || 24 || host will warn if no guest-side >> || || per-cpu warps are expected in >> || || kvmclock. >> diff --git a/Documentation/virtual/kvm/hypercalls.txt b/Documentation/virtual/kvm/hypercalls.txt >> index ea113b5..2a4da11 100644 >> --- a/Documentation/virtual/kvm/hypercalls.txt >> +++ b/Documentation/virtual/kvm/hypercalls.txt >> @@ -64,3 +64,16 @@ Purpose: To enable communication between the hypervisor and guest there is a >> shared page that contains parts of supervisor visible register state. >> The guest can map this shared page to access its supervisor register through >> memory using this hypercall. >> + >> +5. KVM_HC_KICK_CPU >> +------------------------ >> +Architecture: x86 >> +Status: active >> +Purpose: Hypercall used to wakeup a vcpu from HLT state >> +Usage example : A vcpu of a paravirtualized guest that is busywaiting in guest >> +kernel mode for an event to occur (ex: a spinlock to become available) can >> +execute HLT instruction once it has busy-waited for more than a threshold >> +time-interval. Execution of HLT instruction would cause the hypervisor to put >> +the vcpu to sleep until occurence of an appropriate event. Another vcpu of the >> +same guest can wakeup the sleeping vcpu by issuing KVM_HC_KICK_CPU hypercall, >> +specifying APIC ID of the vcpu to be wokenup. > > woken up. Yep. :)