On Wed, 2009-02-25 at 15:54 +0000, Daniel P. Berrange wrote: > On Tue, Feb 24, 2009 at 10:21:47PM +0000, Mark McLoughlin wrote: > > Add implementations of dettach, reattach and reset for > > PCI devices. > > > > Background to this code can be found here: > > > > http://marc.info/?l=kvm&m=123454366317045 > > > > Some notes: > > > > * pci-stub was first introduced in 2.6.29; if it's > > not available, then dettach can only unbind the > > device from the host driver > > > > * remove_id is queued up for 2.6.30; in it's absence > > reattach cannot re-bind the device to the original > > driver > > > > * If the device supports Function Level Reset, we > > just don't bother doing the reset - KVM will do > > this before and after a guest runs > > > > * Currently, if a reset would affect another device > > on the same bus, or another function on the same > > multi-function device, then we just refuse to do > > the reset. In future, we could allow the reset > > as long as it doesn't affect a device in use by > > the host or assigned to another guest > > > > * The device reset code is similar in concept to > > some of Xen's code > > > > Signed-off-by: Mark McLoughlin <markmc@xxxxxxxxxx> > > I can't claim to understand all the gory PCI code in here, > but a few API level suggestions. > > Also, would it be worth (or possible) using libpciaccess.so > for this instead of poking Linux sysfs files directly ? Ah, yes - I knew I forgot another note! Originally the code used libpci, but since that doesn't handle malloc failure (well, you can handle it, but only by exiting) I implemented it directly. libpciaccess looks much saner, so we should use that. It doesn't take much code to implement it, though, so I don't consider switching to the library to be very high priority. > > +static int > > +pciRead(pciDevice *dev, unsigned pos, uint8_t *buf, unsigned buflen) > > +{ > > + memset(buf, 0, buflen); > > + > > + if (pciOpenConfig(dev) < 0) > > + return -1; > > + > > + if (pread(dev->fd, buf, buflen, pos) < 0) { > > + char ebuf[1024]; > > + VIR_WARN(_("Failed to read from '%s' : %s"), dev->path, > > + virStrerror(errno, ebuf, sizeof(ebuf))); > > + return -1; > > + } > > + return 0; > > +} > > I think this needs to check for a possible short read too. > Perhaps better off doing a seek and then saferead(), or > defining a safepread() function. > > > +static int > > +pciWrite(pciDevice *dev, unsigned pos, uint8_t *buf, unsigned buflen) > > +{ > > + if (pciOpenConfig(dev) < 0) > > + return -1; > > + > > + if (pwrite(dev->fd, buf, buflen, pos) < 0) { > > + char ebuf[1024]; > > + VIR_WARN(_("Failed to write to '%s' : %s"), dev->path, > > + virStrerror(errno, ebuf, sizeof(ebuf))); > > + return -1; > > + } > > + return 0; > > +} > > Likewise here needs to validate actual num of bytes written Yep, except we shouldn't see such failures with sysfs - e.g. the likes of libpci doesn't handle such failures. Suggest it's not a big issue and fix it by switching to libpciaccess > > +int > > +pciDettachDevice(pciDevice *dev) > > +{ > > + char path[PATH_MAX]; > > + > > + /* Try loading the pci-stub module if it isn't already loaded; > > + * return an error if there is no pci-stub available. > > + */ > > + if (!virFileExists(PCI_SYSFS "drivers/pci-stub")) { > > + const char *const modprobeargv[] = { MODPROBE, "pci-stub", NULL }; > > + > > + if (virRun(dev->conn, modprobeargv, NULL) < 0) { > > + char ebuf[1024]; > > + VIR_WARN(_("modprobe pci-stub failed: %s"), > > + virStrerror(errno, ebuf, sizeof ebuf)); > > + } > > + } > > + > > + if (!virFileExists(PCI_SYSFS "drivers/pci-stub")) { > > + VIR_WARN(_("pci-stub driver not available, cannot bind device %s to it"), > > + dev->name); > > + } else { > > + /* Add the PCI device ID to pci-stub's dynamic ID table; > > + * this is needed to allow us to bind the device to pci-stub. > > + * Note: if the device is not currently bound to any driver, > > + * pci-stub will immediately be bound to the device. Also, note > > + * that if a new device with this ID is hotplugged, or if a probe > > + * is triggered for such a device, it will also be immediately > > + * bound by pci-stub. > > + */ > > + if (virFileWriteStr(PCI_SYSFS "drivers/pci-stub/new_id", dev->id) < 0) { > > + virReportSystemError(dev->conn, errno, > > + _("Failed to add PCI device ID '%s' to pci-stub/new_id"), > > + dev->id); > > + return -1; > > + } > > + } > > + > > + /* If the device is already bound to a driver, unbind it. > > + * Note, this will have rather unpleasant side effects if this > > + * PCI device happens to be IDE controller for the disk hosting > > + * your root filesystem. > > + */ > > + snprintf(path, sizeof(path), > > + PCI_SYSFS "devices/%s/driver/unbind", dev->name); > > + if (virFileExists(path) && virFileWriteStr(path, dev->name) < 0) { > > + virReportSystemError(dev->conn, errno, > > + _("Failed to unbind PCI device '%s'"), dev->name); > > + return -1; > > + } > > + > > + if (virFileExists(PCI_SYSFS "drivers/pci-stub")) { > > + /* If the device isn't already bound to pci-stub, try binding it now. > > + */ > > + snprintf(path, sizeof(path), PCI_SYSFS "devices/%s/driver", dev->name); > > + if (!virFileLinkPointsTo(path, PCI_SYSFS "drivers/pci-stub") && > > + virFileWriteStr(PCI_SYSFS "drivers/pci-stub/bind", dev->name) < 0) { > > + virReportSystemError(dev->conn, errno, > > + _("Failed to bind PCI device '%s' to pci-stub"), > > + dev->name); > > + return -1; > > + } > > + > > + /* If 'remove_id' exists, remove the device id from pci-stub's dynamic > > + * ID table so that 'drivers_probe' works below. > > + */ > > + if (virFileExists(PCI_SYSFS "drivers/pci-stub/remove_id") && > > + virFileWriteStr(PCI_SYSFS "drivers/pci-stub/remove_id", dev->id) < 0) { > > + virReportSystemError(dev->conn, errno, > > + _("Failed to remove PCI ID '%s' with pci-stub/remove_id"), > > + dev->id); > > + return -1; > > + } > > + } > > + > > + return 0; > > +} > > + > > +int > > +pciReAttachDevice(pciDevice *dev) > > +{ > > + if (virFileExists(PCI_SYSFS "drivers/pci-stub")) { > > + char path[PATH_MAX]; > > + > > + /* If the device is bound to pci-stub, unbind it. > > + */ > > + snprintf(path, sizeof(path), PCI_SYSFS "devices/%s/driver", dev->name); > > + if (virFileLinkPointsTo(path, PCI_SYSFS "drivers/pci-stub") && > > + virFileWriteStr(PCI_SYSFS "drivers/pci-stub/unbind", dev->name) < 0) { > > + virReportSystemError(dev->conn, errno, > > + _("Failed to bind PCI device '%s' to pci-stub"), > > + dev->name); > > + return -1; > > + } > > + } > > + > > + /* Trigger a re-probe of the device is not in pci-stub's dynamic > > + * ID table. If pci-stub is available, but 'remove_id' isn't > > + * available, then re-probing would just cause the device to be > > + * re-bound to pci-stub. > > + */ > > + if (!virFileExists(PCI_SYSFS "drivers/pci-stub") || > > + virFileExists(PCI_SYSFS "drivers/pci-stub/remove_id")) { > > + if (virFileWriteStr(PCI_SYSFS "drivers_probe", dev->name) < 0) { > > + virReportSystemError(dev->conn, errno, > > + _("Failed to trigger a re-probe for PCI device '%s'"), > > + dev->name); > > + return -1; > > + } > > + } > > + > > + return 0; > > +} > > These functions really need to take the driver name as an argument, > so we can pass 'pci-stub' for KVM (or modern pv_ops Xen dom0), or > 'pciback' for old pre-pv_ops Xen dom0. Okay. > > +pciDevice *pciGetDevice (virConnectPtr conn, > > + unsigned vendor, > > + unsigned product, > > + unsigned domain, > > + unsigned bus, > > + unsigned slot, > > + unsigned function); > > +void pciFreeDevice (pciDevice *dev); > > +int pciDettachDevice (pciDevice *dev); > > +int pciReAttachDevice (pciDevice *dev); > > +int pciResetDevice (pciDevice *dev); > > I prefer it to pass the virConnectPtr conn into each of > these calls rather than storing it in the pciDevice > struct. Okay. > It'd also be good to remove the vendor/product > ID here, and have this code lookup them up from te address > info, since the domain XML format only provides the caller > with the domain/bus/slot/function address info. Okay. I'll follow up with a new series with those changes. Cheers, Mark. -- Libvir-list mailing list Libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list