From a2519ad1828dd443af9f9c293db18db6d6123762 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Mon, 24 Oct 2016 16:26:50 +0100 Subject: [PATCH] hw/arm/virt: Set minimum_page_bits to 12 Since the virt board model will never create a CPU which is pre-ARMv7, we know that our minimum page size is 4K and can set minimum_page_bits accordingly, for improved performance. Note that this is a migration compatibility break, so we introduce it only for the virt-2.8 machine and onward; virt-2.7 continues using the old 1K pages. Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson --- hw/arm/virt.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/hw/arm/virt.c b/hw/arm/virt.c index 895446f17c..47ec7ffa73 100644 --- a/hw/arm/virt.c +++ b/hw/arm/virt.c @@ -1499,6 +1499,8 @@ static void virt_machine_class_init(ObjectClass *oc, void *data) mc->block_default_type = IF_VIRTIO; mc->no_cdrom = 1; mc->pci_allow_0_address = true; + /* We know we will never create a pre-ARMv7 CPU which needs 1K pages */ + mc->minimum_page_bits = 12; } static const TypeInfo virt_machine_info = { @@ -1570,6 +1572,8 @@ static void virt_machine_2_7_options(MachineClass *mc) SET_MACHINE_COMPAT(mc, VIRT_COMPAT_2_7); /* ITS was introduced with 2.8 */ vmc->no_its = true; + /* Stick with 1K pages for migration compatibility */ + mc->minimum_page_bits = 0; } DEFINE_VIRT_MACHINE(2, 7) -- 2.11.4.GIT