From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out5-smtp.messagingengine.com ([66.111.4.29]:57479 "EHLO out5-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727389AbeKKNMe (ORCPT ); Sun, 11 Nov 2018 08:12:34 -0500 Subject: FAILED: patch "[PATCH] KVM: arm64: Fix caching of host MDCR_EL2 value" failed to apply to 4.9-stable tree To: mark.rutland@arm.com, christoffer.dall@arm.com, james.morse@arm.com, marc.zyngier@arm.com, robin.murphy@arm.com, will.deacon@arm.com Cc: From: Date: Sat, 10 Nov 2018 17:41:01 -0800 Message-ID: <1541900461144253@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >>From da5a3ce66b8bb51b0ea8a89f42aac153903f90fb Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Wed, 17 Oct 2018 17:42:10 +0100 Subject: [PATCH] KVM: arm64: Fix caching of host MDCR_EL2 value At boot time, KVM stashes the host MDCR_EL2 value, but only does this when the kernel is not running in hyp mode (i.e. is non-VHE). In these cases, the stashed value of MDCR_EL2.HPMN happens to be zero, which can lead to CONSTRAINED UNPREDICTABLE behaviour. Since we use this value to derive the MDCR_EL2 value when switching to/from a guest, after a guest have been run, the performance counters do not behave as expected. This has been observed to result in accesses via PMXEVTYPER_EL0 and PMXEVCNTR_EL0 not affecting the relevant counters, resulting in events not being counted. In these cases, only the fixed-purpose cycle counter appears to work as expected. Fix this by always stashing the host MDCR_EL2 value, regardless of VHE. Cc: Christopher Dall Cc: James Morse Cc: Will Deacon Cc: stable@vger.kernel.org Fixes: 1e947bad0b63b351 ("arm64: KVM: Skip HYP setup when already running in HYP") Tested-by: Robin Murphy Signed-off-by: Mark Rutland Signed-off-by: Marc Zyngier diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c index 4ce99bb223bc..4c5ff06b18f9 100644 --- a/virt/kvm/arm/arm.c +++ b/virt/kvm/arm/arm.c @@ -1296,8 +1296,6 @@ static void cpu_init_hyp_mode(void *dummy) __cpu_init_hyp_mode(pgd_ptr, hyp_stack_ptr, vector_ptr); __cpu_init_stage2(); - - kvm_arm_init_debug(); } static void cpu_hyp_reset(void) @@ -1315,6 +1313,8 @@ static void cpu_hyp_reinit(void) else cpu_init_hyp_mode(NULL); + kvm_arm_init_debug(); + if (vgic_present) kvm_vgic_init_cpu_hardware(); }