[PATCH 4/5] pci-assign: Convert need_emulate_cmd into a bitmask

[Jan Kiszka <jan.kiszka@xxxxxx>]

From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>

Define a mask of PCI command register bits that need to be emulated,
i.e. read back from their shadow state. We will need this for
selectively emulating the INTx mask bit.

Note: No initialization of emulate_cmd_mask to zero needed, the device
state is already zero-initialized.

Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
---
 hw/device-assignment.c |   18 ++++++++++--------
 hw/device-assignment.h |    2 +-
 2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/hw/device-assignment.c b/hw/device-assignment.c
index ef045f4..26d3bd7 100644
--- a/hw/device-assignment.c
+++ b/hw/device-assignment.c
@@ -525,14 +525,17 @@ again:
     DEBUG("(%x.%x): address=%04x val=0x%08x len=%d\n",
           (d->devfn >> 3) & 0x1F, (d->devfn & 0x7), address, val, len);
 
-    if (pci_dev->need_emulate_cmd &&
+    if (pci_dev->emulate_cmd_mask &&
         ranges_overlap(address, len, PCI_COMMAND, 2)) {
         if (address == PCI_COMMAND) {
-            val &= 0xffff0000;
-            val |= pci_default_read_config(d, PCI_COMMAND, 2);
+            val &= ~pci_dev->emulate_cmd_mask;
+            val |= pci_default_read_config(d, PCI_COMMAND, 2) &
+                        pci_dev->emulate_cmd_mask;
         } else {
             /* high-byte access */
-            val = pci_default_read_config(d, PCI_COMMAND+1, 1);
+            val &= ~(pci_dev->emulate_cmd_mask >> 8);
+            val |= pci_default_read_config(d, PCI_COMMAND+1, 1) &
+                        (pci_dev->emulate_cmd_mask >> 8);
         }
     }
 
@@ -800,10 +803,9 @@ again:
 
     /* dealing with virtual function device */
     snprintf(name, sizeof(name), "%sphysfn/", dir);
-    if (!stat(name, &statbuf))
-	    pci_dev->need_emulate_cmd = 1;
-    else
-	    pci_dev->need_emulate_cmd = 0;
+    if (!stat(name, &statbuf)) {
+        pci_dev->emulate_cmd_mask = 0xffff;
+    }
 
     dev->region_number = r;
     return 0;
diff --git a/hw/device-assignment.h b/hw/device-assignment.h
index c94a730..9ead022 100644
--- a/hw/device-assignment.h
+++ b/hw/device-assignment.h
@@ -109,7 +109,7 @@ typedef struct AssignedDevice {
     void *msix_table_page;
     target_phys_addr_t msix_table_addr;
     int mmio_index;
-    int need_emulate_cmd;
+    uint32_t emulate_cmd_mask;
     char *configfd_name;
     QLIST_ENTRY(AssignedDevice) next;
 } AssignedDevice;
-- 
1.7.1

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