From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=54632 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PFe9c-0005EG-Vf for qemu-devel@nongnu.org; Mon, 08 Nov 2010 21:41:50 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PFe9b-00085U-84 for qemu-devel@nongnu.org; Mon, 08 Nov 2010 21:41:48 -0500 Received: from mail.valinux.co.jp ([210.128.90.3]:44775) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PFe9a-00085D-Nm for qemu-devel@nongnu.org; Mon, 08 Nov 2010 21:41:47 -0500 Date: Tue, 9 Nov 2010 11:41:43 +0900 From: Isaku Yamahata Subject: Re: [Qemu-devel] Re: [PATCH] PCI: Bus number from the bridge, not the device Message-ID: <20101109024143.GD4983@valinux.co.jp> References: <20101004215311.17070.54862.stgit@s20.home> <20101108112227.GA1075@redhat.com> <1289227932.19902.11.camel@x201> <20101108162633.GA7962@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20101108162633.GA7962@redhat.com> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: Alex Williamson , qemu-devel@nongnu.org, gleb@redhat.com, armbru@redhat.com On Mon, Nov 08, 2010 at 06:26:33PM +0200, Michael S. Tsirkin wrote: > Replace bus number with slot numbers of parent bridges up to the root. > This works for root bridge in a compatible way because bus number there > is hard-coded to 0. > IMO nested bridges are broken anyway, no way to be compatible there. > > > Gleb, Markus, I think the following should be sufficient for PCI. What > do you think? Also - do we need to update QMP/monitor to teach them to > work with these paths? > > This is on top of Alex's patch, completely untested. > > > pci: fix device path for devices behind nested bridges > > We were using bus number in the device path, which is clearly > broken as this number is guest-assigned for all devices > except the root. > > Fix by using hierarchical list of slots, walking the path > from root down to device, instead. Add :00 as bus number > so that if there are no nested bridges, this is compatible > with what we have now. This format, Domain:00:Slot:Slot....:Slot.Function, doesn't work because pci-to-pci bridge is pci function. So the format should be Domain:00:Slot.Function:Slot.Function....:Slot.Function thanks, > > Signed-off-by: Michael S. Tsirkin > > diff --git a/hw/pci.c b/hw/pci.c > index 7d12473..fa98d94 100644 > --- a/hw/pci.c > +++ b/hw/pci.c > @@ -1826,13 +1826,45 @@ static void pcibus_dev_print(Monitor *mon, DeviceState *dev, int indent) > > static char *pcibus_get_dev_path(DeviceState *dev) > { > - PCIDevice *d = (PCIDevice *)dev; > - char path[16]; > - > - snprintf(path, sizeof(path), "%04x:%02x:%02x.%x", > - pci_find_domain(d->bus), pci_bus_num(d->bus), > - PCI_SLOT(d->devfn), PCI_FUNC(d->devfn)); > - > - return strdup(path); > + PCIDevice *d = container_of(dev, PCIDevice, qdev); > + PCIDevice *t; > + int slot_depth; > + /* Path format: Domain:00:Slot:Slot....:Slot.Function. > + * 00 is added here to make this format compatible with > + * domain:Bus:Slot.Func for systems without nested PCI bridges. > + * Slot list specifies the slot numbers for all devices on the > + * path from root to the specific device. */ > + int domain_len = strlen("DDDD:00"); > + int func_len = strlen(".F"); > + int slot_len = strlen(":SS"); > + int path_len; > + char *path, *p; > + > + /* Calculate # of slots on path between device and root. */; > + slot_depth = 0; > + for (t = d; t; t = t->bus->parent_dev) > + ++slot_depth; > + > + path_len = domain_len + bus_len + slot_len * slot_depth + func_len; > + > + /* Allocate memory, fill in the terminating null byte. */ > + path = malloc(path_len + 1 /* For '\0' */); > + path[path_len] = '\0'; > + > + /* First field is the domain. */ > + snprintf(path, domain_len, "%04x", pci_find_domain(d->bus)); > + > + /* Leave space for slot numbers and fill in function number. */ > + p = path + domain_len + slot_len * slot_depth; > + snprintf(p, func_len, ".%02x", PCI_FUNC(d->devfn)); > + > + /* Fill in slot numbers. We walk up from device to root, so need to print > + * them in the reverse order, last to first. */ > + for (t = d; t; t = t->bus->parent_dev) { > + p -= slot_len; > + snprintf(p, slot_len, ":%x", PCI_SLOT(t->devfn)); > + } > + > + return path; > } > > -- yamahata