The Intel PCI bridge on SuperMicro Atom C3xxx motherboards do not
successfully complete a bus reset when used with certain child devices.
After the reset, config accesses to the child may fail. If assigning
such device via VFIO it will immediately fail with:
vfio-pci 0000:01:00.0: Failed to return from FLR
vfio-pci 0000:01:00.0: timed out waiting for pending transaction;
performing function level reset anyway
Device will disappear from PCI device list:
!!! Unknown header type 7f
Kernel driver in use: vfio-pci
Kernel modules: ddbridge
The attached patch will mark the root port as incapable of doing a
bus level reset. After that all my tested devices survive a VFIO
assignment and several VM reboot cycles.
Signed-off-by: Maik Broemme <mbroe...@libmpq.org>
---
drivers/pci/quirks.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 0f16acc323c6..86cd42872708 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3433,6 +3433,13 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ATHEROS, 0x0034,
quirk_no_bus_reset);
*/
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_CAVIUM, 0xa100, quirk_no_bus_reset);
+/*
+ * Root port on some SuperMicro Atom C3xxx motherboards do not successfully
+ * complete a bus reset when used with certain child devices. After the
+ * reset, config accesses to the child may fail.
+ */
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x19a4, quirk_no_bus_reset);
+
static void quirk_no_pm_reset(struct pci_dev *dev)
{
/*
--
2.21.0
_______________________________________________
vfio-users mailing list
vfio-users@redhat.com
https://www.redhat.com/mailman/listinfo/vfio-users
