[PATCH] hw/pci-host: save/restore pci host config register

[Wang King]

From: Hogan Wang <king.wang@huawei.com>

The pci host config register is used to save PCI address for
read/write config data. If guest write a value to config register,
and then pause the vcpu to migrate, After the migration, the guest
continue to write pci config data, and the write data will be ignored
because of new qemu process lost the config register state.

Example:
1. guest booting in seabios.
2. guest enabled the SMM memory window in piix4_apmc_smm_setup, and
then try to close the SMM memory window.
3. pasued vcpu to finish migration.
4. guest close the SMM memory window fail becasue of config register
state lost.
5. guest continue to boot and crash in ipxe option ROM (SMM memory
window is enabled).

Due to the complex guest, the negative effect is unpredictable.
---
 hw/pci-host/i440fx.c       | 11 +++++++++++
 hw/pci-host/q35.c          | 11 +++++++++++
 hw/pci/pci_host.c          | 11 +++++++++++
 hw/pci/pcie_host.c         | 11 +++++++++++
 include/hw/pci/pci_host.h  | 10 ++++++++++
 include/hw/pci/pcie_host.h | 10 ++++++++++
 6 files changed, 64 insertions(+)

diff --git a/hw/pci-host/i440fx.c b/hw/pci-host/i440fx.c
index 8ed2417f0c..17705bb025 100644
--- a/hw/pci-host/i440fx.c
+++ b/hw/pci-host/i440fx.c
@@ -118,6 +118,16 @@ static const VMStateDescription vmstate_i440fx = {
     }
 };
 
+static const VMStateDescription vmstate_i440fx_pcihost = {
+    .name = "I440FX_PCIHost",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_PCI_HOST(parent_obj, I440FXState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static void i440fx_pcihost_get_pci_hole_start(Object *obj, Visitor *v,
                                               const char *name, void *opaque,
                                               Error **errp)
@@ -398,6 +408,7 @@ static void i440fx_pcihost_class_init(ObjectClass *klass, 
void *data)
     hc->root_bus_path = i440fx_pcihost_root_bus_path;
     dc->realize = i440fx_pcihost_realize;
     dc->fw_name = "pci";
+    dc->vmsd = &vmstate_i440fx_pcihost;
     device_class_set_props(dc, i440fx_props);
     /* Reason: needs to be wired up by pc_init1 */
     dc->user_creatable = false;
diff --git a/hw/pci-host/q35.c b/hw/pci-host/q35.c
index b67cb9c29f..5e323be2e3 100644
--- a/hw/pci-host/q35.c
+++ b/hw/pci-host/q35.c
@@ -165,6 +165,16 @@ static void q35_host_get_pci_hole64_end(Object *obj, 
Visitor *v,
     visit_type_uint64(v, name, &value, errp);
 }
 
+static const VMStateDescription vmstate_q35_pcihost = {
+    .name = "Q35_PCIHost",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_PCIE_HOST(parent_obj, Q35PCIHost),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 /*
  * NOTE: setting defaults for the mch.* fields in this table
  * doesn't work, because mch is a separate QOM object that is
@@ -194,6 +204,7 @@ static void q35_host_class_init(ObjectClass *klass, void 
*data)
 
     hc->root_bus_path = q35_host_root_bus_path;
     dc->realize = q35_host_realize;
+    dc->vmsd = &vmstate_q35_pcihost;
     device_class_set_props(dc, q35_host_props);
     /* Reason: needs to be wired up by pc_q35_init */
     dc->user_creatable = false;
diff --git a/hw/pci/pci_host.c b/hw/pci/pci_host.c
index ce7bcdb1d5..7cdd5a3ea3 100644
--- a/hw/pci/pci_host.c
+++ b/hw/pci/pci_host.c
@@ -24,6 +24,7 @@
 #include "hw/pci/pci_host.h"
 #include "qemu/module.h"
 #include "hw/pci/pci_bus.h"
+#include "migration/vmstate.h"
 #include "trace.h"
 
 /* debug PCI */
@@ -200,6 +201,16 @@ const MemoryRegionOps pci_host_data_be_ops = {
     .endianness = DEVICE_BIG_ENDIAN,
 };
 
+const VMStateDescription vmstate_pcihost = {
+    .name = "PCIHost",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32(config_reg, PCIHostState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static const TypeInfo pci_host_type_info = {
     .name = TYPE_PCI_HOST_BRIDGE,
     .parent = TYPE_SYS_BUS_DEVICE,
diff --git a/hw/pci/pcie_host.c b/hw/pci/pcie_host.c
index 3534006f99..a653c39bb7 100644
--- a/hw/pci/pcie_host.c
+++ b/hw/pci/pcie_host.c
@@ -24,6 +24,7 @@
 #include "hw/pci/pcie_host.h"
 #include "qemu/module.h"
 #include "exec/address-spaces.h"
+#include "migration/vmstate.h"
 
 /* a helper function to get a PCIDevice for a given mmconfig address */
 static inline PCIDevice *pcie_dev_find_by_mmcfg_addr(PCIBus *s,
@@ -121,6 +122,16 @@ void pcie_host_mmcfg_update(PCIExpressHost *e,
     memory_region_transaction_commit();
 }
 
+const VMStateDescription vmstate_pciehost = {
+    .name = "PCIEHost",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_PCI_HOST(pci, PCIExpressHost),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static const TypeInfo pcie_host_type_info = {
     .name = TYPE_PCIE_HOST_BRIDGE,
     .parent = TYPE_PCI_HOST_BRIDGE,
diff --git a/include/hw/pci/pci_host.h b/include/hw/pci/pci_host.h
index 9ce088bd13..fc88305e04 100644
--- a/include/hw/pci/pci_host.h
+++ b/include/hw/pci/pci_host.h
@@ -70,4 +70,14 @@ extern const MemoryRegionOps pci_host_conf_be_ops;
 extern const MemoryRegionOps pci_host_data_le_ops;
 extern const MemoryRegionOps pci_host_data_be_ops;
 
+extern const VMStateDescription vmstate_pcihost;
+
+#define VMSTATE_PCI_HOST(_field, _state) {                           \
+    .name       = (stringify(_field)),                               \
+    .size       = sizeof(PCIHostState),                              \
+    .vmsd       = &vmstate_pcihost,                                  \
+    .flags      = VMS_STRUCT,                                        \
+    .offset     = vmstate_offset_value(_state, _field, PCIHostState),\
+}
+
 #endif /* PCI_HOST_H */
diff --git a/include/hw/pci/pcie_host.h b/include/hw/pci/pcie_host.h
index 3f7b9886d1..a91ba0241a 100644
--- a/include/hw/pci/pcie_host.h
+++ b/include/hw/pci/pcie_host.h
@@ -78,4 +78,14 @@ void pcie_host_mmcfg_update(PCIExpressHost *e,
                                          PCIE_MMCFG_DEVFN_MASK)
 #define PCIE_MMCFG_CONFOFFSET(addr)     ((addr) & PCIE_MMCFG_CONFOFFSET_MASK)
 
+extern const VMStateDescription vmstate_pciehost;
+
+#define VMSTATE_PCIE_HOST(_field, _state) {                            \
+    .name       = (stringify(_field)),                                 \
+    .size       = sizeof(PCIExpressHost),                              \
+    .vmsd       = &vmstate_pcihost,                                    \
+    .flags      = VMS_STRUCT,                                          \
+    .offset     = vmstate_offset_value(_state, _field, PCIExpressHost),\
+}
+
 #endif /* PCIE_HOST_H */
-- 
2.23.0