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authorAndrew Jones <drjones@redhat.com>2016-02-03 13:46:32 +0000
committerPeter Maydell <peter.maydell@linaro.org>2016-02-03 13:46:32 +0000
commita43e68a08bd0d723cc7e480e422a1008a5bb78a9 (patch)
tree9562a0d8f2f5c4d598432b8cc6cb0873ad959738 /hw/arm/virt-acpi-build.c
parent87574621b18f86eab295a2c207e0b42c77b5dfa0 (diff)
downloadqemu-a43e68a08bd0d723cc7e480e422a1008a5bb78a9.zip
virt-acpi-build: add always-on property for timer
This patch is the ACPI equivalent of "hw/arm/virt: Add always-on property to the virt board timer". The timer is always on, and thus setting this informs Linux that it may switch off the periodic timer. Switching off the periodic timer substantially reduces the number of interrupts the host needs to inject. Testing note: AArch64 guests (the only ones currently booting with ACPI) do not actually need this patch to determine it can turn the periodic timer off. I therefore used a hacked guest kernel to ensure this patch works as the equivalent DT patch does. Signed-off-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Shannon Zhao <shannon.zhao@linaro.org> Message-id: 1453380893-26174-1-git-send-email-drjones@redhat.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'hw/arm/virt-acpi-build.c')
-rw-r--r--hw/arm/virt-acpi-build.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
index 87fbe7c97d..f6e538f3d0 100644
--- a/hw/arm/virt-acpi-build.c
+++ b/hw/arm/virt-acpi-build.c
@@ -443,7 +443,7 @@ build_gtdt(GArray *table_data, GArray *linker)
gtdt->secure_el1_flags = ACPI_EDGE_SENSITIVE;
gtdt->non_secure_el1_interrupt = ARCH_TIMER_NS_EL1_IRQ + 16;
- gtdt->non_secure_el1_flags = ACPI_EDGE_SENSITIVE;
+ gtdt->non_secure_el1_flags = ACPI_EDGE_SENSITIVE | ACPI_GTDT_ALWAYS_ON;
gtdt->virtual_timer_interrupt = ARCH_TIMER_VIRT_IRQ + 16;
gtdt->virtual_timer_flags = ACPI_EDGE_SENSITIVE;