From 3622f736cdfa824d68ac8b0a0f1a3725149eb1df Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Mon, 27 Dec 2010 11:21:38 +0200 Subject: [PATCH] pci: fix migration path for devices behind bridges The device path used for migration is currently broken for for all devices behind a nested bridge. Replace this by a hierarchical list of slot/function numbers, walking the path from root down to device. Add :00 after the domain number so that if there are no nested bridges, this is compatible with what we have now. Note: as pointed out by Gleb, using openfirmware paths might be cleaner, doing this would break compatibility though, and the IDs used are not guest or user visible at all, so breaking the compatibility is probably not worth it. Signed-off-by: Michael S. Tsirkin --- hw/pci.c | 48 +++++++++++++++++++++++++++++++++++++----------- 1 file changed, 37 insertions(+), 11 deletions(-) diff --git a/hw/pci.c b/hw/pci.c index 44bb3b9..d0b51b8 100644 --- a/hw/pci.c +++ b/hw/pci.c @@ -2014,17 +2014,43 @@ static char *pcibus_get_fw_dev_path(DeviceState *dev) 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), - 0 /* TODO: need a persistent path for nested buses. - * Note: pci_bus_num(d->bus) is not right as it's guest - * assigned. */, - 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.Function:Slot.Function....:Slot.Function. + * 00 is added here to make this format compatible with + * domain:Bus:Slot.Func for systems without nested PCI bridges. + * Slot.Function list specifies the slot and function numbers for all + * devices on the path from root to the specific device. */ + int domain_len = strlen("DDDD:00"); + int slot_len = strlen(":SS.F"); + 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 + slot_len * slot_depth; + + /* 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:00", pci_find_domain(d->bus)); + + /* Fill in slot numbers. We walk up from device to root, so need to print + * them in the reverse order, last to first. */ + p = path + path_len; + for (t = d; t; t = t->bus->parent_dev) { + p -= slot_len; + snprintf(p, slot_len, ":%02x.%x", PCI_SLOT(t->devfn), PCI_FUNC(d->devfn)); + } + + return path; } static int pci_qdev_find_recursive(PCIBus *bus, -- 2.7.4