From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757500AbcLOMvu (ORCPT ); Thu, 15 Dec 2016 07:51:50 -0500 Received: from mo4-p00-ob.smtp.rzone.de ([81.169.146.221]:17623 "EHLO mo4-p00-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755919AbcLOMvt (ORCPT ); Thu, 15 Dec 2016 07:51:49 -0500 X-RZG-AUTH: :P2EQZWCpfu+qG7CngxMFH1J+yackYocTD1iAi8x+OWi5z/J1IL7CYRxLEwpkY2XtLzyRUcY= X-RZG-CLASS-ID: mo00 Date: Thu, 15 Dec 2016 13:51:39 +0100 From: Olaf Hering To: Vitaly Kuznetsov Cc: kys@microsoft.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, devel@linuxdriverproject.org Subject: Re: move hyperv CHANNELMSG_UNLOAD from crashed kernel to kdump kernel Message-ID: <20161215125139.GC6336@aepfle.de> References: <20161207085110.GC1618@aepfle.de> <87r3594hef.fsf@vitty.brq.redhat.com> <20161215103402.GA6336@aepfle.de> <87mvfx4g4y.fsf@vitty.brq.redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="3siQDZowHQqNOShm" Content-Disposition: inline In-Reply-To: <87mvfx4g4y.fsf@vitty.brq.redhat.com> User-Agent: Mutt/1.7.2 (6888) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --3siQDZowHQqNOShm Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Dec 15, Vitaly Kuznetsov wrote: > We actually need to read the reply and empty the message slot to make > unload happen. And reading on a different CPU may not work, see: >=20 > http://driverdev.linuxdriverproject.org/pipermail/driverdev-devel/2016-De= cember/097330.html Does the following sentences mean the vmbus_signal_eom in vmbus_wait_for_unload is a noop because the wrmsrl() is expected to happen on the other cpu instead of the current cpu? =2E.. - When we read the message we need to clear the slot and signal the fact to the hypervisor. In case there are more messages to this CPU pending the hypervisor will deliver the next message. The signaling is done by writing to an MSR so this can only be done on the appropriate CPU. =2E.. Olaf --3siQDZowHQqNOShm Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iF0EARECAB0WIQSkRyP6Rn//f03pRUBdQqD6ppg2fgUCWFKR1wAKCRBdQqD6ppg2 fj1IAKCVPgH0PvyM17AAu4m8g0AGFimjMACfZsnKaK2v5qFvB5CBRiGpEDRPaak= =bi6y -----END PGP SIGNATURE----- --3siQDZowHQqNOShm--