From mboxrd@z Thu Jan 1 00:00:00 1970 From: Don Dutile Subject: Re: [Qemu-devel] SR-IOV PF reset and QEMU VFs VFIO passthrough Date: Mon, 03 Jun 2013 17:42:16 -0400 Message-ID: <51AD0DB8.8090109@redhat.com> References: <20130601121320.GC5157@irqsave.net> <51ACE340.1030406@redhat.com> <20130603192958.GB31044@irqsave.net> <51AD02B1.8070503@redhat.com> <20130603212723.GG4094@irqsave.net> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1"; Format="flowed" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20130603212723.GG4094-J9ArbTHlV+bR7s880joybQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: =?ISO-8859-1?Q?Beno=EEt_Canet?= Cc: linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, qemu-devel-qX2TKyscuCcdnm+yROfE0A@public.gmane.org List-Id: iommu@lists.linux-foundation.org On 06/03/2013 05:27 PM, Beno=EEt Canet wrote: >>> I was asking this because the PF driver should reset the PF while the V= F are >>> used by VFIO/QEMU when the PF doesn't respond anymore. >>> >> What your VF does while your PF is being reset is PF (& VF) dependent. >> A 'good design' would not impact the VF operation, other than to stall i= t until >> the PF completed reset. My experience, though, is that the PF has to be= brought >> up to some level of functionality to share the physical resources with t= he VFs. > > When the PF does an FLR the hardware go back to its default state, the SR= -IOV > configuration is gone and the VFs disappears from the bus. > Then the restore state function of the kernel reset code would bring the = SR-IOV > PF configuration back. > Ok, now you're a bit mis-led here. The configuration header for SRIOV is _not_ put back. Only the std, PCI config header section is put back in place, along with msi(x), pm-caps. If the hw wipes out all VF state setup (which it should, IMO), all VF confi= guration will be lost in the hw... *but*, the PCI core will still think the VFs exist (not hot-unplugged, no m= ore than PF was); trying to setup the VFs again, will fail (or worse). > The hardware also have a privately owned SR-IOV related configuration in = the PF > configuration space. This configuration is used to configure the VFs reso= urces. > (memory) > Per the SRIOV spec, yes, but that's in PCIe ext cfg space. That area of the PCI configuration is not saved or restored by dev-reset. > Best regards > > Beno=EEt Canet > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > More majordomo info at http://vger.kernel.org/majordomo-info.html