[Qemu-devel] [PATCH] ARM: Virt: Don't generate RTC ACPI node when using UEFI

[Shannon Zhao]

When booting VM through UEFI, UEFI takes ownership of the RTC hardware.
To DTB UEFI could call libfdt api to disable the RTC device node, but to
ACPI it couldn't do that. Therefore, we don't generate the RTC ACPI
device in QEMU when using UEFI.

Signed-off-by: Shannon Zhao <address@hidden>
---
 hw/arm/virt-acpi-build.c         | 13 +++++++++++--
 hw/arm/virt.c                    |  5 ++++-
 include/hw/arm/virt-acpi-build.h |  1 +
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
index 0caf5ce..cccec79 100644
--- a/hw/arm/virt-acpi-build.c
+++ b/hw/arm/virt-acpi-build.c
@@ -575,8 +575,17 @@ build_dsdt(GArray *table_data, GArray *linker, 
VirtGuestInfo *guest_info)
     acpi_dsdt_add_cpus(scope, guest_info->smp_cpus);
     acpi_dsdt_add_uart(scope, &memmap[VIRT_UART],
                        (irqmap[VIRT_UART] + ARM_SPI_BASE));
-    acpi_dsdt_add_rtc(scope, &memmap[VIRT_RTC],
-                      (irqmap[VIRT_RTC] + ARM_SPI_BASE));
+
+    /* When booting VM through UEFI, UEFI takes ownership of the RTC hardware.
+     * To DTB UEFI could call libfdt api to disable the RTC device node, but to
+     * ACPI it couldn't do that. Therefore, we don't generate the RTC ACPI
+     * device here when using UEFI.
+     */
+    if (guest_info->acpi_rtc) {
+        acpi_dsdt_add_rtc(scope, &memmap[VIRT_RTC],
+                          (irqmap[VIRT_RTC] + ARM_SPI_BASE));
+    }
+
     acpi_dsdt_add_flash(scope, &memmap[VIRT_FLASH]);
     acpi_dsdt_add_virtio(scope, &memmap[VIRT_MMIO],
                     (irqmap[VIRT_MMIO] + ARM_SPI_BASE), NUM_VIRTIO_TRANSPORTS);
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index fd52b76..de12037 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -1002,6 +1002,7 @@ static void machvirt_init(MachineState *machine)
     VirtGuestInfoState *guest_info_state = g_malloc0(sizeof *guest_info_state);
     VirtGuestInfo *guest_info = &guest_info_state->info;
     char **cpustr;
+    bool firmware_loaded;
 
     if (!cpu_model) {
         cpu_model = "cortex-a15";
@@ -1124,12 +1125,14 @@ static void machvirt_init(MachineState *machine)
     create_fw_cfg(vbi, &address_space_memory);
     rom_set_fw(fw_cfg_find());
 
+    firmware_loaded = bios_name || drive_get(IF_PFLASH, 0, 0);
     guest_info->smp_cpus = smp_cpus;
     guest_info->fw_cfg = fw_cfg_find();
     guest_info->memmap = vbi->memmap;
     guest_info->irqmap = vbi->irqmap;
     guest_info->use_highmem = vms->highmem;
     guest_info->gic_version = gic_version;
+    guest_info->acpi_rtc = !firmware_loaded;
     guest_info_state->machine_done.notify = virt_guest_info_machine_done;
     qemu_add_machine_init_done_notifier(&guest_info_state->machine_done);
 
@@ -1141,7 +1144,7 @@ static void machvirt_init(MachineState *machine)
     vbi->bootinfo.board_id = -1;
     vbi->bootinfo.loader_start = vbi->memmap[VIRT_MEM].base;
     vbi->bootinfo.get_dtb = machvirt_dtb;
-    vbi->bootinfo.firmware_loaded = bios_name || drive_get(IF_PFLASH, 0, 0);
+    vbi->bootinfo.firmware_loaded = firmware_loaded;
     arm_load_kernel(ARM_CPU(first_cpu), &vbi->bootinfo);
 
     /*
diff --git a/include/hw/arm/virt-acpi-build.h b/include/hw/arm/virt-acpi-build.h
index 744b666..6f412a4 100644
--- a/include/hw/arm/virt-acpi-build.h
+++ b/include/hw/arm/virt-acpi-build.h
@@ -33,6 +33,7 @@ typedef struct VirtGuestInfo {
     const int *irqmap;
     bool use_highmem;
     int gic_version;
+    bool acpi_rtc;
 } VirtGuestInfo;
 
 
-- 
2.1.0