From 01a2ecb4c38fe4a35455ea706e76984ee8d5a769 Mon Sep 17 00:00:00 2001 From: Eduardo Habkost Date: Thu, 13 Dec 2018 15:52:00 +0000 Subject: [PATCH 2/5] rhel: Set host-phys-bits-limit=48 on rhel machine-types RH-Author: Eduardo Habkost Message-id: <20181213155200.20300-3-ehabkost@redhat.com> Patchwork-id: 83480 O-Subject: [RHEL8/rhel qemu-kvm PATCH 2/2] rhel: Set host-phys-bits-limit=48 on rhel machine-types Bugzilla: 1598284 RH-Acked-by: Dr. David Alan Gilbert RH-Acked-by: Pankaj Gupta RH-Acked-by: Bandan Das RH-Acked-by: Paolo Bonzini Upstream status: not applicable Currently we use the host physical address size by default on VMs. This was a good default on most cases, but this is not the case on host CPUs supporting 5-level EPT. On those cases, we want VMs to use 4-level EPT by default. Ensure VMs will use 4-level EPT by default, by limiting physical address bits to 48. Not applicable upstream because upstream doesn't set host-phys-bits=on by default. Signed-off-by: Eduardo Habkost Signed-off-by: Danilo C. L. de Paula --- include/hw/i386/pc.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h index 285e8df..c29176d 100644 --- a/include/hw/i386/pc.h +++ b/include/hw/i386/pc.h @@ -963,6 +963,11 @@ extern void igd_passthrough_isa_bridge_create(PCIBus *bus, uint16_t gpu_dev_id); .property = "host-phys-bits",\ .value = "on",\ },\ + { /* PC_RHEL_COMPAT */ \ + .driver = TYPE_X86_CPU,\ + .property = "host-phys-bits-limit",\ + .value = "48",\ + },\ { /* PC_RHEL_COMPAT bz 1508330 */ \ .driver = "vfio-pci",\ .property = "x-no-geforce-quirks",\ -- 1.8.3.1