From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754000Ab2A3QB6 (ORCPT ); Mon, 30 Jan 2012 11:01:58 -0500 Received: from oz.csail.mit.edu ([128.30.30.239]:47789 "EHLO mail.mgebm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753769Ab2A3QB4 (ORCPT ); Mon, 30 Jan 2012 11:01:56 -0500 Date: Mon, 30 Jan 2012 11:01:55 -0500 From: Eric B Munson To: Avi Kivity Cc: mingo@redhat.com, hpa@zytor.com, ryanh@linux.vnet.ibm.com, aliguori@us.ibm.com, mtosatti@redhat.com, jeremy.fitzhardinge@citrix.com, kvm@vger.kernel.org, linux-arch@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, Jan Kiszka Subject: Re: [PATCH 3/4 V10] Add ioctl for KVMCLOCK_GUEST_STOPPED Message-ID: <20120130160155.GC6875@mgebm.net> References: <1326825641-15765-1-git-send-email-emunson@mgebm.net> <1326825641-15765-4-git-send-email-emunson@mgebm.net> <4F26B220.9050101@redhat.com> <20120130153244.GA6875@mgebm.net> <4F26BC1A.8060002@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="da4uJneut+ArUgXk" Content-Disposition: inline In-Reply-To: <4F26BC1A.8060002@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --da4uJneut+ArUgXk Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, 30 Jan 2012, Avi Kivity wrote: > On 01/30/2012 05:32 PM, Eric B Munson wrote: > > >=20 > > > Can you point me to the discussion that moved this to be a vm ioctl? = In > > > general vm ioctls that do things for all vcpus are racy, like here.= =20 > > > You're accessing variables that are protected by the vcpu mutex, and = not > > > taking the mutex (nor can you, since it is held while the guest is > > > running, unlike most kernel mutexes). > > >=20 > > > > Jan Kiszka suggested that becuase there isn't a use case for notifying > > individual vcpus (can vcpu's be paused individually? >=20 > They can, though the guest will grind to a halt very soon. >=20 > > ) that it makes more sense > > to have a vm ioctl. > > > > http://thread.gmane.org/gmane.comp.emulators.qemu/131624 > > > > If the per vcpu ioctl is the right choice I can resend those patches. >=20 > The races are solvable but I think it's easier in userspace. It's also > more flexible, though I don't really see a use for this flexibility. >=20 Okay, I will rebase the per vcpu patches and resend those. Eric --da4uJneut+ArUgXk Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQIcBAEBAgAGBQJPJr7yAAoJEKhG9nGc1bpJQhsP/RkU11sX0jurHXtYNTRWpHtS I3L784GLjY3FMOIE5Ox12+m0MMzTXXlnr5cA7wYB0MNYwp6jf6RazIOwv6j6LrKJ d1a3AWwluQ5ZZ6a8B223m4BXVz5aDifIhcUGQZFzcpdQVQFvn6i8O961u0zRxwCi IGezhs16e18KgJywKt02DUnfZvbZiok2LXFRtFwdu4gOGUmIhF0D5kGqBTUdZwnF Mtim2ibSZT3Ccp1PzoZnFIWuwhmqbXV/ozm+/SA29Wj7M1LSgiYIer/M3XkaSvE6 hE16Fr7IKPZjRX/SbGJRUnMk/UKPyo8UfJyGlbkF5cBt4/zC354elKqPru67vuSe SpCMeWqQDTYDyFmd+g/uUyCm/lmyxdtvrLgLtZN2K0jhjglrN4zdSd4dphchAIFn FmJLcs+ygP58ViLGacU+jriSmYomNKoP1CbtV6i5fQaP9Ob1xpjH3CyPlY/o1lDE JN8ilRDdTYNrIg1mwuJFZX02aMMnthSF2WvbhLVPPabYArNHVQHkhEqZ/Vkx0WzW 0MgSQMhAo/zW4K2lgqAIIJmeGld9aIG/RJkQJVrVCdu1JoiEL4b5oDM0Njrghdi0 mKWzgepBep6pxpSurOzQcgJ0VTuJ5c7tjt3Nz5WI0UmxRIEX80QLhz3l2VbQkAjq 70N4vkfD35GeHruWGLS/ =geGP -----END PGP SIGNATURE----- --da4uJneut+ArUgXk--