From: Guoyi Tu <tugy@chinatelecom.cn>

The PCI_COMMAND register is located at offset 4 within
the PCI configuration space and occupies 2 bytes. The
interrupt disable bit is at the 10th bit, which corresponds
to the byte at offset 5 in the PCI configuration space.

In our testing environment, the guest driver may directly
updates the byte at offset 5 in the PCI configuration space.
The backtrace looks like as following:
    at hw/pci/pci.c:1442
    at hw/virtio/virtio-pci.c:605
    val=5, len=1) at hw/pci/pci_host.c:81

In this situation, the range_covers_byte function called
by the pci_default_write_config function will return false,
resulting in the inability to handle the interrupt disable
update event.

To fix this issue, we can use the ranges_overlap function
instead of range_covers_byte to determine whether the interrupt
bit has been updated.

Signed-off-by: Guoyi Tu <tugy@chinatelecom.cn>
Signed-off-by: yuanminghao <yuanmh12@chinatelecom.cn>
Message-Id: <ce2d0437-8faa-4d61-b536-4668f645a959@chinatelecom.cn>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Fixes: b6981cb57be5 ("pci: interrupt disable bit support")
---
 hw/pci/pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index b8d22e2e74..881d774fb6 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -1613,7 +1613,7 @@ void pci_default_write_config(PCIDevice *d, uint32_t addr, uint32_t val_in, int
         range_covers_byte(addr, l, PCI_COMMAND))
         pci_update_mappings(d);
 
-    if (range_covers_byte(addr, l, PCI_COMMAND)) {
+    if (ranges_overlap(addr, l, PCI_COMMAND, 2)) {
         pci_update_irq_disabled(d, was_irq_disabled);
         memory_region_set_enabled(&d->bus_master_enable_region,
                                   (pci_get_word(d->config + PCI_COMMAND)
-- 
MST