[Qemu-devel] [PATCH, RFC] pci: allow PCI devices to fix address space

["Andreas Färber" <andreas.faerber@web.de>]

From: Hervé Poussineau <hpoussin@reactos.org>

v1:
* Rebased.

Signed-off-by: Hervé Poussineau <hpoussin@reactos.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Andreas Färber <andreas.faerber@web.de>
---
 
 Hello Michael,
 
 Could you please take a look at this? I'm out of my field here.
 
 The intention of the first part appears to be to save (val & ~mask),
 whereas the inline helper would've returned (val & mask).
 
 The second part makes existing code conditional on that value.
 
 Regards,
 Andreas
 
 hw/pci.c |   22 ++++++++++++++--------
 1 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/hw/pci.c b/hw/pci.c
index ef00d20..4db4b1f 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -140,6 +140,7 @@ static void pci_update_irq_status(PCIDevice *dev)
 static void pci_device_reset(PCIDevice *dev)
 {
     int r;
+    uint16_t cmd;
     /* TODO: call the below unconditionally once all pci devices
      * are qdevified */
     if (dev->qdev.info) {
@@ -149,9 +150,10 @@ static void pci_device_reset(PCIDevice *dev)
     dev->irq_state = 0;
     pci_update_irq_status(dev);
     /* Clear all writeable bits */
-    pci_word_test_and_clear_mask(dev->config + PCI_COMMAND,
-                                 pci_get_word(dev->wmask + PCI_COMMAND) |
-                                 pci_get_word(dev->w1cmask + PCI_COMMAND));
+    cmd = pci_get_word(dev->config + PCI_COMMAND);
+    cmd &= ~(pci_get_word(dev->wmask + PCI_COMMAND) |
+             pci_get_word(dev->w1cmask + PCI_COMMAND));
+    pci_set_word(dev->config + PCI_COMMAND, cmd);
     pci_word_test_and_clear_mask(dev->config + PCI_STATUS,
                                  pci_get_word(dev->wmask + PCI_STATUS) |
                                  pci_get_word(dev->w1cmask + PCI_STATUS));
@@ -163,11 +165,15 @@ static void pci_device_reset(PCIDevice *dev)
             continue;
         }
 
-        if (!(region->type & PCI_BASE_ADDRESS_SPACE_IO) &&
-            region->type & PCI_BASE_ADDRESS_MEM_TYPE_64) {
-            pci_set_quad(dev->config + pci_bar(dev, r), region->type);
-        } else {
-            pci_set_long(dev->config + pci_bar(dev, r), region->type);
+        if ((region->type == PCI_BASE_ADDRESS_SPACE_IO && !(cmd & PCI_COMMAND_MEMORY)) ||
+            (region->type == PCI_BASE_ADDRESS_SPACE_MEMORY && !(cmd & PCI_COMMAND_IO))) {
+            /* Reset region address, as it it is not read-only */
+            if (!(region->type & PCI_BASE_ADDRESS_SPACE_IO) &&
+                region->type & PCI_BASE_ADDRESS_MEM_TYPE_64) {
+                pci_set_quad(dev->config + pci_bar(dev, r), region->type);
+            } else {
+                pci_set_long(dev->config + pci_bar(dev, r), region->type);
+            }
         }
     }
     pci_update_mappings(dev);
-- 
1.7.3.4