pci: Honour wmask when resetting PCI_INTERRUPT_LINE

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 <mark.cave-ayland@ilande.co.uk>
Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Tested-by: BALATON Zoltan <balaton@eik.bme.hu>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-id: 20200313082444.2439-4-mark.cave-ayland@ilande.co.uk
Signed-off-by: John Snow <jsnow@redhat.com>

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index e1ed6677e1a5c11d1d597799690254e06d1f674a..b5bc842fac6ac613dc5e72a70fa44b8563a19e52 100644 (file)
--- 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) {