[Qemu-devel] [PATCH 2/2] pcie_aer: clear cmask for Advanced Error Interrupt Message Number

[Jason Baron <jbaron@redhat.com>]

The Advanced Error Interrupt Message Number (bits 31:27 of the Root
Error Status Register) is updated when the number of msi messages assigned to a
device changes. Migration of windows 7 on q35 chipset failed because the check
in get_pci_config_device() fails due to wmask being set on these bits. Its valid
to update these bits and we must restore this state across migration.

Signed-off-by: Jason Baron <jbaron@redhat.com>
---
 hw/pcie_aer.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/hw/pcie_aer.c b/hw/pcie_aer.c
index 3b6981c..6edcd79 100644
--- a/hw/pcie_aer.c
+++ b/hw/pcie_aer.c
@@ -738,6 +738,12 @@ void pcie_aer_root_init(PCIDevice *dev)
                  PCI_ERR_ROOT_CMD_EN_MASK);
     pci_set_long(dev->w1cmask + pos + PCI_ERR_ROOT_STATUS,
                  PCI_ERR_ROOT_STATUS_REPORT_MASK);
+    /* Bits 31:27 - Advanced Error Interrupt Message Number
+     * These bits are updated when the number of MSI messages changes.
+     * By clearing the cmask, pcie devices can be migrated.
+     */
+    pci_set_long(dev->cmask + pos + PCI_ERR_ROOT_STATUS,
+                 (1 << PCI_ERR_ROOT_IRQ_SHIFT) - 1);
 }
 
 void pcie_aer_root_reset(PCIDevice *dev)
-- 
1.7.1