[Xen-changelog] [qemu-xen master] vfio/pci: fix out-of-sync BAR information on reset

[patchbot@xxxxxxx]

commit a52a4c471703e995ceb06f6157d70747823e8a0d
Author:     Ido Yariv <ido@xxxxxxxxxx>
AuthorDate: Mon Oct 31 09:53:04 2016 -0600
Commit:     Alex Williamson <alex.williamson@xxxxxxxxxx>
CommitDate: Mon Oct 31 09:53:04 2016 -0600

    vfio/pci: fix out-of-sync BAR information on reset
    
    When a PCI device is reset, pci_do_device_reset resets all BAR addresses
    in the relevant PCIDevice's config buffer.
    
    The VFIO configuration space stays untouched, so the guest OS may choose
    to skip restoring the BAR addresses as they would seem intact. The PCI
    device may be left non-operational.
    One example of such a scenario is when the guest exits S3.
    
    Fix this by resetting the BAR addresses in the VFIO configuration space
    as well.
    
    Signed-off-by: Ido Yariv <ido@xxxxxxxxxx>
    Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
---
 hw/vfio/pci.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 65d30fd..b399742 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -1922,11 +1922,23 @@ static void vfio_pci_pre_reset(VFIOPCIDevice *vdev)
 static void vfio_pci_post_reset(VFIOPCIDevice *vdev)
 {
     Error *err = NULL;
+    int nr;
 
     vfio_intx_enable(vdev, &err);
     if (err) {
         error_reportf_err(err, ERR_PREFIX, vdev->vbasedev.name);
     }
+
+    for (nr = 0; nr < PCI_NUM_REGIONS - 1; ++nr) {
+        off_t addr = vdev->config_offset + PCI_BASE_ADDRESS_0 + (4 * nr);
+        uint32_t val = 0;
+        uint32_t len = sizeof(val);
+
+        if (pwrite(vdev->vbasedev.fd, &val, len, addr) != len) {
+            error_report("%s(%s) reset bar %d failed: %m", __func__,
+                         vdev->vbasedev.name, nr);
+        }
+    }
 }
 
 static bool vfio_pci_host_match(PCIHostDeviceAddress *addr, const char *name)
--
generated by git-patchbot for /home/xen/git/qemu-xen.git#master

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