[Qemu-devel] [RFC QEMU PATCH v4 05/10] xen-hvm: initialize fw_cfg interface

[Haozhong Zhang <haozhong.zhang@intel.com>]

Xen is going to reuse QEMU to build ACPI of some devices (e.g., NFIT
and SSDT for NVDIMM) for HVM domains. The existing QEMU ACPI build
code requires a fw_cfg interface which will also be used to pass QEMU
built ACPI to Xen. Therefore, we need to initialize fw_cfg when any
ACPI is going to be built by QEMU.

Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
---
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Anthony Perard <anthony.perard@citrix.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Eduardo Habkost <ehabkost@redhat.com>
---
 hw/i386/xen/xen-hvm.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/hw/i386/xen/xen-hvm.c b/hw/i386/xen/xen-hvm.c
index fe01b7a025..4b29f4052b 100644
--- a/hw/i386/xen/xen-hvm.c
+++ b/hw/i386/xen/xen-hvm.c
@@ -14,6 +14,7 @@
 #include "hw/pci/pci.h"
 #include "hw/i386/pc.h"
 #include "hw/i386/apic-msidef.h"
+#include "hw/loader.h"
 #include "hw/xen/xen_common.h"
 #include "hw/xen/xen_backend.h"
 #include "qmp-commands.h"
@@ -1234,6 +1235,14 @@ static void xen_wakeup_notifier(Notifier *notifier, void *data)
     xc_set_hvm_param(xen_xc, xen_domid, HVM_PARAM_ACPI_S_STATE, 0);
 }
 
+static void xen_fw_cfg_init(PCMachineState *pcms)
+{
+    FWCfgState *fw_cfg = fw_cfg_init_io(FW_CFG_IO_BASE);
+
+    rom_set_fw(fw_cfg);
+    pcms->fw_cfg = fw_cfg;
+}
+
 void xen_hvm_init(PCMachineState *pcms, MemoryRegion **ram_memory)
 {
     int i, rc;
@@ -1384,6 +1393,9 @@ void xen_hvm_init(PCMachineState *pcms, MemoryRegion **ram_memory)
 
     /* Disable ACPI build because Xen handles it */
     pcms->acpi_build_enabled = false;
+    if (pcms->acpi_build_enabled) {
+        xen_fw_cfg_init(pcms);
+    }
 
     return;
 
-- 
2.15.1