Linux Virtualization - Jun 2009 - [PATCHv4 02/13] qemu: capability bits in pci save/restore

Add support for capability bits in save/restore for pci.
These will be used for MSI, where the capability might
be present or not as requested by user, which does not
map well into a single version number.

Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
---
 hw/pci.c |   17 ++++++++++++++---
 hw/pci.h |    4 ++++
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/hw/pci.c b/hw/pci.c
index 766e0c6..6740b07 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -126,9 +126,13 @@ int pci_bus_num(PCIBus *s)
 
 void pci_device_save(PCIDevice *s, QEMUFile *f)
 {
+    int version = s->cap_present ? 3 : 2;
     int i;
 
-    qemu_put_be32(f, 2); /* PCI device version */
+    /* PCI device version and capabilities */
+    qemu_put_be32(f, version);
+    if (version >= 3)
+        qemu_put_be32(f, s->cap_present);
     qemu_put_buffer(f, s->config, 256);
     for (i = 0; i < 4; i++)
         qemu_put_be32(f, s->irq_state[i]);
@@ -140,15 +144,22 @@ int pci_device_load(PCIDevice *s, QEMUFile *f)
     int i;
 
     version_id = qemu_get_be32(f);
-    if (version_id > 2)
+    if (version_id > 3)
         return -EINVAL;
+    if (version_id >= 3)
+        s->cap_present = qemu_get_be32(f);
+    else
+        s->cap_present = 0;
+
+    if (s->cap_present & ~s->cap_supported)
+        return -EINVAL;
+
     qemu_get_buffer(f, s->config, 256);
     pci_update_mappings(s);
 
     if (version_id >= 2)
         for (i = 0; i < 4; i ++)
             s->irq_state[i] = qemu_get_be32(f);
-
     return 0;
 }
 
diff --git a/hw/pci.h b/hw/pci.h
index c50ea50..656badc 100644
--- a/hw/pci.h
+++ b/hw/pci.h
@@ -174,6 +174,10 @@ struct PCIDevice {
 
     /* Current IRQ levels.  Used internally by the generic PCI code.  */
     int irq_state[4];
+
+    /* Capability bits for save/load */
+    uint32_t cap_supported;
+    uint32_t cap_present;
 };
 
 PCIDevice *pci_register_device(PCIBus *bus, const char *name,
-- 
1.6.3.1.56.g79e1.dirty