From a43e68a08bd0d723cc7e480e422a1008a5bb78a9 Mon Sep 17 00:00:00 2001 From: Andrew Jones Date: Wed, 3 Feb 2016 13:46:32 +0000 Subject: [PATCH] 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 Reviewed-by: Shannon Zhao Message-id: 1453380893-26174-1-git-send-email-drjones@redhat.com Signed-off-by: Peter Maydell --- hw/arm/virt-acpi-build.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) 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;