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@eu.citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
Committed-by: Ian Campbell <ian.campbell@citrix.com>

diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
index 1587fa2fb51b5128ee53de198750b4747426d500..b6d701535d388e9e27d5b6c5ccd881a1347dff69 100644 (file)
--- 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 let 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);