[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v3] libxl/PCI: Fix PV hotplug & stubdom coldplug
commit 0fdb48ffe7a1 "libxl: Make sure devices added by pci-attach are reflected in the config" broken PCI hotplug (xl pci-attach) for PV domains when it moved libxl__create_pci_backend() later in the function. This also broke HVM + stubdom PCI passthrough coldplug. For that, the PCI devices are hotplugged to a running PV stubdom, and then the QEMU QMP device_add commands are made to QEMU inside the stubdom. Are running PV domain calls libxl__wait_for_backend(). With the current placement of libxl__create_pci_backend(), the path does not exist and the call immediately fails: libxl: error: libxl_device.c:1388:libxl__wait_for_backend: Backend /local/domain/0/backend/pci/43/0 does not exist libxl: error: libxl_pci.c:1764:device_pci_add_done: Domain 42:libxl__device_pci_add failed for PCI device 0:2:0.0 (rc -3) libxl: error: libxl_create.c:1857:domcreate_attach_devices: Domain 42:unable to add pci devices The wait is only relevant when the backend is already present. num_devs is already used to determine if the backend needs to be created. Re-use num_devs to determine if the backend wait is necessary. The wait is necessary to avoid racing with another PCI attachment reconfiguring the front/back or changing to some other state like closing. If we are creating the backend, then we don't have to worry about the state since it is being created. Fixes: 0fdb48ffe7a1 ("libxl: Make sure devices added by pci-attach are reflected in the config") Signed-off-by: Jason Andryuk <jandryuk@xxxxxxxxx> --- Alternative to Jan's patch: https://lore.kernel.org/xen-devel/5114ae87-bc0e-3d58-e16e-6d9d2fee0801@xxxxxxxx/ v3: Change title & commit message v2: https://lore.kernel.org/xen-devel/20210812005700.3159-1-jandryuk@xxxxxxxxx/ Add Fixes Expand num_devs use in commit message --- tools/libs/light/libxl_pci.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/tools/libs/light/libxl_pci.c b/tools/libs/light/libxl_pci.c index 4c2d7aeefb..e8fd3bd937 100644 --- a/tools/libs/light/libxl_pci.c +++ b/tools/libs/light/libxl_pci.c @@ -157,8 +157,10 @@ static int libxl__device_pci_add_xenstore(libxl__gc *gc, if (domtype == LIBXL_DOMAIN_TYPE_INVALID) return ERROR_FAIL; - if (!starting && domtype == LIBXL_DOMAIN_TYPE_PV) { - if (libxl__wait_for_backend(gc, be_path, GCSPRINTF("%d", XenbusStateConnected)) < 0) + /* wait is only needed if the backend already exists (num_devs != NULL) */ + if (num_devs && !starting && domtype == LIBXL_DOMAIN_TYPE_PV) { + if (libxl__wait_for_backend(gc, be_path, + GCSPRINTF("%d", XenbusStateConnected)) < 0) return ERROR_FAIL; } -- 2.32.0
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |