From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33254) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dBO1a-00029G-4r for qemu-devel@nongnu.org; Thu, 18 May 2017 12:11:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dBO1Z-00055s-BT for qemu-devel@nongnu.org; Thu, 18 May 2017 12:11:38 -0400 From: Wei Huang Date: Thu, 18 May 2017 11:11:29 -0500 Message-Id: <1495123889-32301-1-git-send-email-wei@redhat.com> Subject: [Qemu-devel] [PATCH 1/1] target/arm: clear PMUVER field of AA64DFR0 when vPMU=off List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-arm@nongnu.org Cc: qemu-devel@nongnu.org, peter.maydell@linaro.org The PMUv3 driver of linux kernel (in arch/arm64/kernel/perf_event.c) relies on the PMUVER field of id_aa64dfr0_el1 to decide if PMU support is present or not. This patch clears the PMUVER field under TCG mode when vPMU=off. Without it, PMUv3 will init insider guest VMs even with vPMU=off. This patch also removes a redundant line inside the if-statement. Signed-off-by: Wei Huang --- target/arm/cpu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/target/arm/cpu.c b/target/arm/cpu.c index c185eb1..4e8fe1c 100644 --- a/target/arm/cpu.c +++ b/target/arm/cpu.c @@ -750,8 +750,8 @@ static void arm_cpu_realizefn(DeviceState *dev, Error **errp) } if (!cpu->has_pmu) { - cpu->has_pmu = false; unset_feature(env, ARM_FEATURE_PMU); + cpu->id_aa64dfr0 &= ~0xf00; } if (!arm_feature(env, ARM_FEATURE_EL2)) { -- 1.8.3.1