From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [Xen-devel] [PATCH 2/5] xen/pciback: Support pci_reset_function, aka FLR or D3 support. Date: Thu, 5 Jan 2012 16:34:23 -0500 Message-ID: <20120105213423.GC5180@phenom.dumpdata.com> References: <1325724403-29642-1-git-send-email-konrad.wilk@oracle.com> <1325724403-29642-3-git-send-email-konrad.wilk@oracle.com> <1325759051.25206.361.camel@zakaz.uk.xensource.com> <4F05F2EA.5030502@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <4F05F2EA.5030502@redhat.com> Sender: linux-pci-owner@vger.kernel.org To: Don Dutile Cc: Ian Campbell , "linux-kernel@vger.kernel.org" , "jbarnes@virtuousgeek.org" , "linux-pci@vger.kernel.org" , "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org On Thu, Jan 05, 2012 at 01:58:50PM -0500, Don Dutile wrote: > On 01/05/2012 05:24 AM, Ian Campbell wrote: > >On Thu, 2012-01-05 at 00:46 +0000, Konrad Rzeszutek Wilk wrote: > >>We use the __pci_reset_function_locked to perform the action. > >>Also on attaching ("bind") and detaching ("unbind") we save and > >>restore the configuration states. When the device is disconnected > >>from a guest we use the "pci_reset_function" to also reset the > >>device before being passed to another guest. > > > >Currently I thought the toolstack was supposed to do the reset (by > >writing to the reset node in sysfs) as it was (de)assigning devices > >to/from guests. That's not to say that there isn't an argument for > >preferring to do it kernels side but it would be interesting to make > >that argument explicitly. > > > >I guess the toolstack doesn't currently save/restore the configuration > >state, could it though? I guess the state is all available in sysfs. On > pci_reset_function() saves the config state before doing a fcn-level reset. > > the libvirt toolstack handles the unbind/reset/bind functionality > and is used by kvm for it's device assignment. The KVM assigned PCI module does the call as well via the ioctls when assigning/de-assigning the PCI device. Look in 'kvm_free_assigned_device' and in 'kvm_vm_ioctl_assign_device'. Is that what you mean by the unbind/reset/bind functionality - the ioctl call?