vfio/pci : Add pba_offset PCI quirk for Chelsio T5 devices

Fix pba_offset initialization value for Chelsio T5 Virtual Function
device. The T5 hardware has a bug in it where it reports a Pending Interrupt
Bit Array Offset of 0x8000 for its SR-IOV Virtual Functions instead
of the 0x1000 that the hardware actually uses internally. As the hardware
doesn't return the correct pba_offset value, add a quirk to instead
return a hardcoded value of 0x1000 when a Chelsio T5 VF device is
detected.

This bug has been fixed in the Chelsio's next chip series T6 but there are
no plans to respin the T5 ASIC for this bug. It is just documented in the
T5 Errata and left it at that.

Signed-off-by: Gabriel Laupre <glaupre@chelsio.com>
Reviewed-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 27b7ec133e..2ed877fe9f 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -2252,6 +2252,33 @@ static int vfio_early_setup_msix(VFIOPCIDevice *vdev)
     vdev->msix->pba_offset = pba & ~PCI_MSIX_FLAGS_BIRMASK;
     vdev->msix->entries = (ctrl & PCI_MSIX_FLAGS_QSIZE) + 1;
 
+    /*
+     * Test the size of the pba_offset variable and catch if it extends outside
+     * of the specified BAR. If it is the case, we need to apply a hardware
+     * specific quirk if the device is known or we have a broken configuration.
+     */
+    if (vdev->msix->pba_offset >=
+        vdev->bars[vdev->msix->pba_bar].region.size) {
+
+        PCIDevice *pdev = &vdev->pdev;
+        uint16_t vendor = pci_get_word(pdev->config + PCI_VENDOR_ID);
+        uint16_t device = pci_get_word(pdev->config + PCI_DEVICE_ID);
+
+        /*
+         * Chelsio T5 Virtual Function devices are encoded as 0x58xx for T5
+         * adapters. The T5 hardware returns an incorrect value of 0x8000 for
+         * the VF PBA offset while the BAR itself is only 8k. The correct value
+         * is 0x1000, so we hard code that here.
+         */
+        if (vendor == PCI_VENDOR_ID_CHELSIO && (device & 0xff00) == 0x5800) {
+            vdev->msix->pba_offset = 0x1000;
+        } else {
+            error_report("vfio: Hardware reports invalid configuration, "
+                         "MSIX PBA outside of specified BAR");
+            return -EINVAL;
+        }
+    }
+
     trace_vfio_early_setup_msix(vdev->vbasedev.name, pos,
                                 vdev->msix->table_bar,
                                 vdev->msix->table_offset,