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Re: [Qemu-devel] [PATCH v3] ARM: Virt: Don't generate RTC ACPI device wh
From: |
Andrew Jones |
Subject: |
Re: [Qemu-devel] [PATCH v3] ARM: Virt: Don't generate RTC ACPI device when using UEFI |
Date: |
Fri, 15 Jan 2016 15:18:40 +0100 |
User-agent: |
Mutt/1.5.23.1 (2014-03-12) |
On Fri, Jan 15, 2016 at 10:11:31PM +0800, Shannon Zhao wrote:
> When booting the VM with UEFI, UEFI takes ownership of the RTC hardware.
> While UEFI can use libfdt to disable the RTC device node in the DTB that
> it passes to the OS, it cannot modify AML. Therefore, we won't generate
> the RTC ACPI device at all when using UEFI.
>
> Signed-off-by: Shannon Zhao <address@hidden>
> Acked-by: Ard Biesheuvel <address@hidden>
> Reviewed-by: Laszlo Ersek <address@hidden>
> ---
> V3: add comments to explain why it doesn't generate RTC ACPI device
> ---
> hw/arm/virt-acpi-build.c | 24 +++++-------------------
> 1 file changed, 5 insertions(+), 19 deletions(-)
>
> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> index 0caf5ce..0d5c635 100644
> --- a/hw/arm/virt-acpi-build.c
> +++ b/hw/arm/virt-acpi-build.c
> @@ -94,23 +94,6 @@ static void acpi_dsdt_add_uart(Aml *scope, const
> MemMapEntry *uart_memmap,
> aml_append(scope, dev);
> }
>
> -static void acpi_dsdt_add_rtc(Aml *scope, const MemMapEntry *rtc_memmap,
> - uint32_t rtc_irq)
> -{
> - Aml *dev = aml_device("RTC0");
> - aml_append(dev, aml_name_decl("_HID", aml_string("LNRO0013")));
> - aml_append(dev, aml_name_decl("_UID", aml_int(0)));
> -
> - Aml *crs = aml_resource_template();
> - aml_append(crs, aml_memory32_fixed(rtc_memmap->base,
> - rtc_memmap->size, AML_READ_WRITE));
> - aml_append(crs,
> - aml_interrupt(AML_CONSUMER, AML_LEVEL, AML_ACTIVE_HIGH,
> - AML_EXCLUSIVE, &rtc_irq, 1));
> - aml_append(dev, aml_name_decl("_CRS", crs));
> - aml_append(scope, dev);
> -}
> -
> static void acpi_dsdt_add_flash(Aml *scope, const MemMapEntry *flash_memmap)
> {
> Aml *dev, *crs;
> @@ -571,12 +554,15 @@ build_dsdt(GArray *table_data, GArray *linker,
> VirtGuestInfo *guest_info)
> /* Reserve space for header */
> acpi_data_push(dsdt->buf, sizeof(AcpiTableHeader));
>
> + /* When booting the VM with UEFI, UEFI takes ownership of the RTC
> hardware.
> + * While UEFI can use libfdt to disable the RTC device node in the DTB
> that
> + * it passes to the OS, it cannot modify AML. Therefore, we won't
> generate
> + * the RTC ACPI device at all when using UEFI.
> + */
> scope = aml_scope("\\_SB");
> 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));
> 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);
> --
> 2.1.0
>
>
Reviewed-by: Andrew Jones <address@hidden>