From 565efbc8a7145c47379543edfcc84fc4f4dd6d83 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Roger=20Pau=20Monn=C3=A9?= Date: Mon, 16 Jul 2018 15:11:42 +0200 Subject: [PATCH] docs/pvh: document initial MTRR state MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Provided to both Dom0 and DomUs. Signed-off-by: Roger Pau Monné --- docs/misc/pvh.markdown | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/docs/misc/pvh.markdown b/docs/misc/pvh.markdown index e85fb15374..1c9a00b48a 100644 --- a/docs/misc/pvh.markdown +++ b/docs/misc/pvh.markdown @@ -92,3 +92,21 @@ event channels. Delivery of those interrupts can be configured in the same way as HVM guests, check xen/include/public/hvm/params.h and xen/include/public/hvm/hvm\_op.h for more information about available delivery methods. + +## MTRR ## + +### Unprivileged guests ### + +PVH guests are currently booted with the default MTRR type set to write-back +and MTRR enabled. This allows DomUs to start with a sane MTRR state. Note that +this will have to be revisited when pci-passthrough is added to PVH in order to +set MMIO regions as UC. + +Xen guarantees that RAM regions will always have the WB cache type set in the +initial MTRR state, either set by the default MTRR type or by other means. + +### Hardware domain ### + +A PVH hardware domain is booted with the same MTRR state as the one found on +the host. This is done because the hardware domain memory map is already a +modified copy of the host memory map, so the same MTRR setup should work. -- 2.30.2