virtio-pci: fix migration for pci bus master

Current support for bus master (clearing OK bit) together with the need to
support guests which do not enable PCI bus mastering, leads to extra state in
VIRTIO_PCI_FLAG_BUS_MASTER_BUG bit, which isn't robust in case of cross-version
migration for the case when guests use the device before setting DRIVER_OK.

Rip out this code, and replace it:
-   Modern QEMU doesn't need VIRTIO_PCI_FLAG_BUS_MASTER_BUG
    so just drop it for latest machine type.
-   For compat machine types, set PCI_COMMAND if DRIVER_OK
    is set.

As this is needed for 2.1 for both pc and ppc, move PC_COMPAT macros from pc.h
to a new common header.

Cc: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Alexander Graf <agraf@suse.de>

2 files changed, 2 insertions, 2 deletions

diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 061f4d9..ddc885e 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -474,7 +474,7 @@ static QEMUMachine pc_i440fx_machine_v2_1 = {
     .name = "pc-i440fx-2.1",
     .init = pc_init_pci,
     .compat_props = (GlobalProperty[]) {
-        PC_COMPAT_2_1,
+        HW_COMPAT_2_1,
         { /* end of list */ }
     },
 };
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 9c44cd6..f533a94 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -370,7 +370,7 @@ static QEMUMachine pc_q35_machine_v2_1 = {
     .name = "pc-q35-2.1",
     .init = pc_q35_init,
     .compat_props = (GlobalProperty[]) {
-        PC_COMPAT_2_1,
+        HW_COMPAT_2_1,
         { /* end of list */ }
     },
 };