From patchwork Tue Apr 26 08:21:48 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 566564 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 58F96C433EF for ; Tue, 26 Apr 2022 08:53:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243847AbiDZI4x (ORCPT ); Tue, 26 Apr 2022 04:56:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55742 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346358AbiDZIyo (ORCPT ); Tue, 26 Apr 2022 04:54:44 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 47178DAFCA; Tue, 26 Apr 2022 01:41:10 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id D11F5B81CED; Tue, 26 Apr 2022 08:41:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4114EC385AC; Tue, 26 Apr 2022 08:41:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1650962468; bh=ZxgTw4UzvfWbr0evmQdbxSaSvx3FVMuFHEdvOCmww5A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cmIlqoCw8pOdIN/uFdLTjF/fRtPK8h/jviOq8ITy4p7Kjkg5rBlrg7TvVtppQHpKo JMD77Vnzgt/nr/4kOoBbdwDuTjA+K+0THbHok7eEpc2dCVDnUBVTzAZAcCLYN+28E0 ttuhCCc4fRJzbrGH8BrlVPUG98Dm3pJGz0mY6DsI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dongli Cao , Like Xu , Yanan Wang , Jim Mattson , Paolo Bonzini Subject: [PATCH 5.15 107/124] KVM: x86/pmu: Update AMD PMC sample period to fix guest NMI-watchdog Date: Tue, 26 Apr 2022 10:21:48 +0200 Message-Id: <20220426081750.337095129@linuxfoundation.org> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220426081747.286685339@linuxfoundation.org> References: <20220426081747.286685339@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Like Xu commit 75189d1de1b377e580ebd2d2c55914631eac9c64 upstream. NMI-watchdog is one of the favorite features of kernel developers, but it does not work in AMD guest even with vPMU enabled and worse, the system misrepresents this capability via /proc. This is a PMC emulation error. KVM does not pass the latest valid value to perf_event in time when guest NMI-watchdog is running, thus the perf_event corresponding to the watchdog counter will enter the old state at some point after the first guest NMI injection, forcing the hardware register PMC0 to be constantly written to 0x800000000001. Meanwhile, the running counter should accurately reflect its new value based on the latest coordinated pmc->counter (from vPMC's point of view) rather than the value written directly by the guest. Fixes: 168d918f2643 ("KVM: x86: Adjust counter sample period after a wrmsr") Reported-by: Dongli Cao Signed-off-by: Like Xu Reviewed-by: Yanan Wang Tested-by: Yanan Wang Reviewed-by: Jim Mattson Message-Id: <20220409015226.38619-1-likexu@tencent.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/pmu.h | 9 +++++++++ arch/x86/kvm/svm/pmu.c | 1 + arch/x86/kvm/vmx/pmu_intel.c | 8 ++------ 3 files changed, 12 insertions(+), 6 deletions(-) --- a/arch/x86/kvm/pmu.h +++ b/arch/x86/kvm/pmu.h @@ -141,6 +141,15 @@ static inline u64 get_sample_period(stru return sample_period; } +static inline void pmc_update_sample_period(struct kvm_pmc *pmc) +{ + if (!pmc->perf_event || pmc->is_paused) + return; + + perf_event_period(pmc->perf_event, + get_sample_period(pmc, pmc->counter)); +} + void reprogram_gp_counter(struct kvm_pmc *pmc, u64 eventsel); void reprogram_fixed_counter(struct kvm_pmc *pmc, u8 ctrl, int fixed_idx); void reprogram_counter(struct kvm_pmu *pmu, int pmc_idx); --- a/arch/x86/kvm/svm/pmu.c +++ b/arch/x86/kvm/svm/pmu.c @@ -256,6 +256,7 @@ static int amd_pmu_set_msr(struct kvm_vc pmc = get_gp_pmc_amd(pmu, msr, PMU_TYPE_COUNTER); if (pmc) { pmc->counter += data - pmc_read_counter(pmc); + pmc_update_sample_period(pmc); return 0; } /* MSR_EVNTSELn */ --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -439,15 +439,11 @@ static int intel_pmu_set_msr(struct kvm_ !(msr & MSR_PMC_FULL_WIDTH_BIT)) data = (s64)(s32)data; pmc->counter += data - pmc_read_counter(pmc); - if (pmc->perf_event && !pmc->is_paused) - perf_event_period(pmc->perf_event, - get_sample_period(pmc, data)); + pmc_update_sample_period(pmc); return 0; } else if ((pmc = get_fixed_pmc(pmu, msr))) { pmc->counter += data - pmc_read_counter(pmc); - if (pmc->perf_event && !pmc->is_paused) - perf_event_period(pmc->perf_event, - get_sample_period(pmc, data)); + pmc_update_sample_period(pmc); return 0; } else if ((pmc = get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0))) { if (data == pmc->eventsel)