[Xen-devel] [PATCH v2 1/5] arm/vtimer: do not let the guest interact with the physical timer

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

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>
Acked-by: Tim Deegan <tim@xxxxxxx>
---
 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..b6d7015 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 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);
-- 
1.7.2.5


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