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-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=768b250b31361bf8acfef4b7dca61ee37c91f3f6;p=people%2Froyger%2Fxen.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 927c827ea1..fab140d48d 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();