[PATCH 3/7] pci: Honour wmask when resetting PCI_INTERRUPT_LINE

[Mark Cave-Ayland]

From: BALATON Zoltan <address@hidden>

The pci_do_device_reset() function (called from pci_device_reset)
clears the PCI_INTERRUPT_LINE config reg of devices on the bus but did
this without taking wmask into account. We'll have a device model now
that needs to set a constant value for this reg and this patch allows
to do that without additional workaround in device emulation to
reverse the effect of this PCI bus reset function.

Suggested-by: Mark Cave-Ayland <address@hidden>
Signed-off-by: BALATON Zoltan <address@hidden>
Reviewed-by: Michael S. Tsirkin <address@hidden>
Reviewed-by: Mark Cave-Ayland <address@hidden>
---
 hw/pci/pci.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index e1ed6677e1..b5bc842fac 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -302,8 +302,11 @@ static void pci_do_device_reset(PCIDevice *dev)
     pci_word_test_and_clear_mask(dev->config + PCI_STATUS,
                                  pci_get_word(dev->wmask + PCI_STATUS) |
                                  pci_get_word(dev->w1cmask + PCI_STATUS));
+    /* Some devices make bits of PCI_INTERRUPT_LINE read only */
+    pci_byte_test_and_clear_mask(dev->config + PCI_INTERRUPT_LINE,
+                              pci_get_word(dev->wmask + PCI_INTERRUPT_LINE) |
+                              pci_get_word(dev->w1cmask + PCI_INTERRUPT_LINE));
     dev->config[PCI_CACHE_LINE_SIZE] = 0x0;
-    dev->config[PCI_INTERRUPT_LINE] = 0x0;
     for (r = 0; r < PCI_NUM_REGIONS; ++r) {
         PCIIORegion *region = &dev->io_regions[r];
         if (!region->size) {
-- 
2.20.1