From: Jun Sun <jsun@junsun.net>
Date: Mon, 10 Oct 2016 19:27:56 +0000 (-0700)
Subject: Don't clear HCR_VM bit when updating VTTBR.
X-Git-Tag: archive/raspbian/4.11.1-1+rpi1~1^2~66^2~3270
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/%22/%22http:/www.example.com/cgi/%22?a=commitdiff_plain;h=c655b112fb5fd677e0943dafaa1071501f8fc190;p=xen.git

Don't clear HCR_VM bit when updating VTTBR.

Currently function p2m_restore_state() would clear HCR_VM bit, i.e.,
disabling stage2 translation, before updating VTTBR register. After
some research and talking to ARM support, I got confirmed that this is not
necessary. We are currently working on a new platform that would need this
to be removed.

The patch is tested on FVP foundation model.

Signed-off-by: Jun Sun <jsun@junsun.net>
Acked-by: Steve Capper <steve.capper@linaro.org>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
---

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index cc5634bd17..e4991df42f 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -140,8 +140,6 @@ void p2m_restore_state(struct vcpu *n)
         return;
 
     hcr = READ_SYSREG(HCR_EL2);
-    WRITE_SYSREG(hcr & ~HCR_VM, HCR_EL2);
-    isb();
 
     WRITE_SYSREG64(p2m->vttbr, VTTBR_EL2);
     isb();