From 3c601c5f056fba055b7a1438b84b69fc649275c3 Mon Sep 17 00:00:00 2001 From: Jeff Kubascik Date: Tue, 21 Jan 2020 10:07:04 -0500 Subject: [PATCH] xen/arm: Sign extend TimerValue when computing the CompareValue Xen will only store the CompareValue as it can be derived from the TimerValue (ARM DDI 0487E.a section D11.2.4): CompareValue = (Counter[63:0] + SignExtend(TimerValue))[63:0] While the TimerValue is a 32-bit signed value, our implementation assumed it is a 32-bit unsigned value. Signed-off-by: Jeff Kubascik Acked-by: Julien Grall --- xen/arch/arm/vtimer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/xen/arch/arm/vtimer.c b/xen/arch/arm/vtimer.c index 08411f33a9..6d39fc944f 100644 --- a/xen/arch/arm/vtimer.c +++ b/xen/arch/arm/vtimer.c @@ -215,7 +215,7 @@ static bool vtimer_cntp_tval(struct cpu_user_regs *regs, uint32_t *r, } else { - v->arch.phys_timer.cval = cntpct + *r; + v->arch.phys_timer.cval = cntpct + (uint64_t)(int32_t)*r; if ( v->arch.phys_timer.ctl & CNTx_CTL_ENABLE ) { v->arch.phys_timer.ctl &= ~CNTx_CTL_PENDING; -- 2.39.5