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[Xen-devel] [PATCH 1/5] arm/vtimer: do not let the guest interact with the physical timer



The guest can read the physical counter but it shouldn't be able to
cause interrupts of the physical timer to go to the hypervisor.
Trap physical timer reads/writes in vtimer.c instead.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
 xen/arch/arm/time.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
index 1587fa2..d5b71d7 100644
--- a/xen/arch/arm/time.c
+++ b/xen/arch/arm/time.c
@@ -160,8 +160,8 @@ void __cpuinit init_timer_interrupt(void)
     WRITE_CP64(0, CNTVOFF);     /* No VM-specific offset */
     WRITE_CP32(0, CNTKCTL);     /* No user-mode access */
 #if USE_HYP_TIMER
-    /* Let the VMs read the physical counter and timer so they can tell time */
-    WRITE_CP32(CNTHCTL_PA|CNTHCTL_TA, CNTHCTL);
+    /* Do not the VMs program the physical timer, only read the physical 
counter */
+    WRITE_CP32(CNTHCTL_PA, CNTHCTL);
 #else
     /* Cannot let VMs access physical counter if we are using it */
     WRITE_CP32(0, CNTHCTL);
-- 
1.7.2.5


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