From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:33610) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S5GDW-0001sE-59 for qemu-devel@nongnu.org; Wed, 07 Mar 2012 07:44:04 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1S5GCx-00024K-11 for qemu-devel@nongnu.org; Wed, 07 Mar 2012 07:43:41 -0500 Received: from mx1.redhat.com ([209.132.183.28]:63289) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S5GCw-00023r-Pn for qemu-devel@nongnu.org; Wed, 07 Mar 2012 07:43:06 -0500 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q27Ch40H021530 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 7 Mar 2012 07:43:04 -0500 Date: Wed, 7 Mar 2012 14:43:03 +0200 From: Gleb Natapov Message-ID: <20120307124303.GI2521@redhat.com> References: <20120307000340.3079.87515.stgit@bling.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120307000340.3079.87515.stgit@bling.home> Subject: Re: [Qemu-devel] [PATCH 0/6] PCI hotplug improvements List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alex Williamson Cc: ddutile@redhat.com, qemu-devel@nongnu.org, mst@redhat.com On Tue, Mar 06, 2012 at 05:13:36PM -0700, Alex Williamson wrote: > Here's a re-work of the patch that added _STA for the purpose of > using it as an ack from the guest. Instead of that, add a notifier > for device access. Once the guest reads from device config space, > it owns it. Until that point, we can remove it directly. As pointed > out by MST, this passes test b) below, which the _STA method would not. > As a bonus, no bios change is required for this. Patches 5 & 6 are > just cleanups that can be applied independently. Thanks, > While I agree with Michael that using _STA as ack is a hack I think this approach is not less of a hack. It is unlikely that this is how it work on bare metal and we should follow real HW if possible. > Alex > > Tested using Linux guest: > a) without acpiphp loaded: > - device_add (nothing happens) > - device_del (device removed directly) How it works on real HW? On non ACPI compliant guest hot plug unplug is not suppose to work. > b) without acpiphp loaded: > - device_add (nothing happens) > - echo 1 > /sys/bus/pci/rescan (device discovered) > - device_del (nothing happens, guest owns device) So guest can block a device from being ever removed? > - modprobe acpiphp > - device_del (guest releases device) > c) with acpiphp loaded: > - device_add/del behave as expected (automatic add + coordinated removal) > Tested using WinXP guest: > - device_add/del behave as expected (automatic add + coordinated removal) > > --- > > Alex Williamson (6): > api_piix4: Remove PCI_RMV_BASE write code > acpi_piix4: Use pci_get/set_byte > acpi_piix4: Track PCI hotplug status and allow non-ACPI remove path > pci: Add notifier for device probing > acpi_piix4: Only allow writes to PCI hotplug eject register > acpi_piix4: Disallow write to up/down PCI hotplug registers > > > hw/acpi_piix4.c | 175 ++++++++++++++++++++++++++++--------------------------- > hw/pci_host.c | 19 ++++++ > hw/pci_host.h | 2 + > 3 files changed, 111 insertions(+), 85 deletions(-) -- Gleb.