VFIO supports pass-through of devices to user space - for sake of illustration, say a PCI e1000 device:
- the e1000 is first unbound from the PCI e1000 driver via sysfs - the vfio-pci driver is told via new_id that it now handles e1000 devices - the e1000 is explicitly bound to vfio-pci through sysfs However, now we have two drivers in the system that both handle e1000 devices. A hotplug event could then occur and it is ambiguous as to which driver will claim the device. The desired semantics is that vfio-pci is only bound to devices by explicit request in sysfs. This patch makes this possible by introducing a sysfs_bind_only flag in struct device_driver. Signed-off-by: Stuart Yoder <stuart.yo...@freescale.com> Signed-off-by: Kim Phillips <kim.phill...@linaro.org> --- this patchset is available on top of the WIP exynos-iommu v10 [1] and vfio-platform v2 [2] patchsets, here: git://git.linaro.org/people/kimphill/linux.git binding-dev [1] http://www.spinics.net/lists/linux-samsung-soc/msg23301.html [2] http://www.spinics.net/lists/kvm/msg96701.html drivers/base/dd.c | 5 ++++- include/linux/device.h | 2 ++ 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 35fa368..6f85279 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -389,7 +389,7 @@ static int __device_attach(struct device_driver *drv, void *data) { struct device *dev = data; - if (!driver_match_device(drv, dev)) + if (drv->sysfs_bind_only || !driver_match_device(drv, dev)) return 0; return driver_probe_device(drv, dev); @@ -476,6 +476,9 @@ static int __driver_attach(struct device *dev, void *data) */ int driver_attach(struct device_driver *drv) { + if (drv->sysfs_bind_only) + return 0; + return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach); } EXPORT_SYMBOL_GPL(driver_attach); diff --git a/include/linux/device.h b/include/linux/device.h index 2a9d6ed..e63c3fe 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -203,6 +203,7 @@ extern struct klist *bus_get_device_klist(struct bus_type *bus); * @owner: The module owner. * @mod_name: Used for built-in modules. * @suppress_bind_attrs: Disables bind/unbind via sysfs. + * @sysfs_bind_only: Only allow bind/unbind via sysfs. * @of_match_table: The open firmware table. * @acpi_match_table: The ACPI match table. * @probe: Called to query the existence of a specific device, @@ -236,6 +237,7 @@ struct device_driver { const char *mod_name; /* used for built-in modules */ bool suppress_bind_attrs; /* disables bind/unbind via sysfs */ + bool sysfs_bind_only; /* only allow bind/unbind via sysfs */ const struct of_device_id *of_match_table; const struct acpi_device_id *acpi_match_table; -- 1.8.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
