[Qemu-devel] [PATCH v1] pci: Don't register a specialized 'config_write' if default behavior is intended

[Shmulik Ladkani <shmulik.ladkani@ravellosystems.com>]

Few devices have their specialized 'config_write' methods which simply
call 'pci_default_write_config' followed by a 'msix_write_config' or
'msi_write_config' calls, using exact same arguments.

This is unnecessary as 'pci_default_write_config' already invokes
'msi_write_config' and 'msix_write_config'.

Also, since 'pci_default_write_config' is the default 'config_write'
handler, we can simply avoid the registration of these specialized
versions.

Cc: Leonid Shatz <leonid.shatz@ravellosystems.com>
Signed-off-by: Shmulik Ladkani <shmulik.ladkani@ravellosystems.com>
---

NOTE:
Not sure if my statement regarding ommitting 'config_write' holds for
the megasas case:
It's parent is TYPE_MEGASAS_BASE whose parent is TYPE_PCI_DEVICE.
Can we assume 'config_write' will be set to 'pci_default_write_config'
in this case?

 hw/misc/ivshmem.c    | 1 -
 hw/net/vmxnet3.c     | 9 ---------
 hw/scsi/megasas.c    | 8 --------
 hw/scsi/vmw_pvscsi.c | 8 --------
 4 files changed, 26 deletions(-)

diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
index 5d272c8..231c35f 100644
--- a/hw/misc/ivshmem.c
+++ b/hw/misc/ivshmem.c
@@ -698,7 +698,6 @@ static void ivshmem_write_config(PCIDevice *pci_dev, uint32_t address,
 				 uint32_t val, int len)
 {
     pci_default_write_config(pci_dev, address, val, len);
-    msix_write_config(pci_dev, address, val, len);
 }
 
 static int pci_ivshmem_init(PCIDevice *dev)
diff --git a/hw/net/vmxnet3.c b/hw/net/vmxnet3.c
index 8bcdf3e..104a0f5 100644
--- a/hw/net/vmxnet3.c
+++ b/hw/net/vmxnet3.c
@@ -2477,14 +2477,6 @@ static const VMStateDescription vmstate_vmxnet3 = {
     }
 };
 
-static void
-vmxnet3_write_config(PCIDevice *pci_dev, uint32_t addr, uint32_t val, int len)
-{
-    pci_default_write_config(pci_dev, addr, val, len);
-    msix_write_config(pci_dev, addr, val, len);
-    msi_write_config(pci_dev, addr, val, len);
-}
-
 static Property vmxnet3_properties[] = {
     DEFINE_NIC_PROPERTIES(VMXNET3State, conf),
     DEFINE_PROP_END_OF_LIST(),
@@ -2503,7 +2495,6 @@ static void vmxnet3_class_init(ObjectClass *class, void *data)
     c->class_id = PCI_CLASS_NETWORK_ETHERNET;
     c->subsystem_vendor_id = PCI_VENDOR_ID_VMWARE;
     c->subsystem_id = PCI_DEVICE_ID_VMWARE_VMXNET3;
-    c->config_write = vmxnet3_write_config,
     dc->desc = "VMWare Paravirtualized Ethernet v3";
     dc->reset = vmxnet3_qdev_reset;
     dc->vmsd = &vmstate_vmxnet3;
diff --git a/hw/scsi/megasas.c b/hw/scsi/megasas.c
index 91a5d97..51ba9e0 100644
--- a/hw/scsi/megasas.c
+++ b/hw/scsi/megasas.c
@@ -2407,13 +2407,6 @@ static void megasas_scsi_realize(PCIDevice *dev, Error **errp)
     }
 }
 
-static void
-megasas_write_config(PCIDevice *pci, uint32_t addr, uint32_t val, int len)
-{
-    pci_default_write_config(pci, addr, val, len);
-    msi_write_config(pci, addr, val, len);
-}
-
 static Property megasas_properties_gen1[] = {
     DEFINE_PROP_UINT32("max_sge", MegasasState, fw_sge,
                        MEGASAS_DEFAULT_SGE),
@@ -2516,7 +2509,6 @@ static void megasas_class_init(ObjectClass *oc, void *data)
     dc->vmsd = info->vmsd;
     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
     dc->desc = info->desc;
-    pc->config_write = megasas_write_config;
 }
 
 static const TypeInfo megasas_info = {
diff --git a/hw/scsi/vmw_pvscsi.c b/hw/scsi/vmw_pvscsi.c
index c6148d3..9c71f31 100644
--- a/hw/scsi/vmw_pvscsi.c
+++ b/hw/scsi/vmw_pvscsi.c
@@ -1174,13 +1174,6 @@ static const VMStateDescription vmstate_pvscsi = {
     }
 };
 
-static void
-pvscsi_write_config(PCIDevice *pci, uint32_t addr, uint32_t val, int len)
-{
-    pci_default_write_config(pci, addr, val, len);
-    msi_write_config(pci, addr, val, len);
-}
-
 static Property pvscsi_properties[] = {
     DEFINE_PROP_UINT8("use_msg", PVSCSIState, use_msg, 1),
     DEFINE_PROP_END_OF_LIST(),
@@ -1202,7 +1195,6 @@ static void pvscsi_class_init(ObjectClass *klass, void *data)
     dc->vmsd = &vmstate_pvscsi;
     dc->props = pvscsi_properties;
     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
-    k->config_write = pvscsi_write_config;
     hc->unplug = pvscsi_hot_unplug;
     hc->plug = pvscsi_hotplug;
 }
-- 
1.9.1