From patchwork Fri Jan 26 08:54:38 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiong Zhang X-Patchwork-Id: 13532272 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 75FB514F547; Fri, 26 Jan 2024 08:58:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.12 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706259519; cv=none; b=RXJP5dkVDfBvtRpeVm4rDZ+eGvFjkES9Qapq+97cZMiG91/JHirBle1hEgP87+/cHtFPK67cJxl3kKKAJMOJsWrKKeJCAN0hrZjuBYmRXHL6OFliiYT8gwjytDxTFKCDMg2p+ThNvSozKQ62DOb+LAYQV/NsfoeYnK08TkNhhv4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706259519; c=relaxed/simple; bh=Ljh9yt1ZTZazh8g8HMDGH1EBGrH5rCz+avVoyaVnQW0=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=h7FckSGJ45OuwP1N29hFRYhOGNsybCPeQcZr+j8MYd5zi6xtBmqfYNdzOzSXAlNTchch31cGaP/g+XCWz+LZNZUX8yYxSWIUVgXT5vqb/5bjTiBZ1kmX4gpSlehUH6VxkvMAlbWPINfZimW86j+5Cg1Z5EExlXkJTcMrPy+TDr8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=B6N9e6bh; arc=none smtp.client-ip=198.175.65.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="B6N9e6bh" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1706259519; x=1737795519; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Ljh9yt1ZTZazh8g8HMDGH1EBGrH5rCz+avVoyaVnQW0=; b=B6N9e6bhNtLqJSDKICtGGx0xZuhj2Sv4Lx9oP5e0L0yiMa/uoQF4CqFq BP/qZFV8iXvC+4csqJfYVj020yBu13qsFWK0faaKI+3fblCfYV+WD8oba QNS4eGcsMklNln0ndpS0K5X2U4+PXhKvwlwuAk7vX55V9zMB0qO0SJyAm zlQ0phnECrXLnK18QyZDf1GGua1BEDcPswts8BSDY+xh7fa5UlYLnxNkQ YQZF6XcDVvEFl5iXue33CPLbtok/jAPgmSeCCvf32lWGtSYm1Vsp+Tmgk uWre2CUogfjpMTwG+gDHtAoL3gbRiq/e7vCoi6eZOL1/OdavQI/fwc66I Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10964"; a="9792988" X-IronPort-AV: E=Sophos;i="6.05,216,1701158400"; d="scan'208";a="9792988" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orvoesa104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Jan 2024 00:58:34 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10964"; a="930310443" X-IronPort-AV: E=Sophos;i="6.05,216,1701158400"; d="scan'208";a="930310443" Received: from yanli3-mobl.ccr.corp.intel.com (HELO xiongzha-desk1.ccr.corp.intel.com) ([10.254.213.178]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Jan 2024 00:58:28 -0800 From: Xiong Zhang To: seanjc@google.com, pbonzini@redhat.com, peterz@infradead.org, mizhang@google.com, kan.liang@intel.com, zhenyuw@linux.intel.com, dapeng1.mi@linux.intel.com, jmattson@google.com Cc: kvm@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, zhiyuan.lv@intel.com, eranian@google.com, irogers@google.com, samantha.alt@intel.com, like.xu.linux@gmail.com, chao.gao@intel.com, xiong.y.zhang@linux.intel.com, Xiong Zhang Subject: [RFC PATCH 35/41] KVM: x86/pmu: Allow writing to event selector for GP counters if event is allowed Date: Fri, 26 Jan 2024 16:54:38 +0800 Message-Id: <20240126085444.324918-36-xiong.y.zhang@linux.intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240126085444.324918-1-xiong.y.zhang@linux.intel.com> References: <20240126085444.324918-1-xiong.y.zhang@linux.intel.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Mingwei Zhang Only allow writing to event selector if event is allowed in filter. Since passthrough PMU implementation does the PMU context switch at VM Enter/Exit boudary, even if the value of event selector passes the checking, it cannot be written directly to HW since PMU HW is owned by the host PMU at the moment. Because of that, introduce eventsel_hw to cache that value which will be assigned into HW just before VM entry. Note that regardless of whether an event value is allowed, the value will be cached in pmc->eventsel and guest VM can always read the cached value back. This implementation is consistent with the HW CPU design. Signed-off-by: Xiong Zhang Signed-off-by: Mingwei Zhang --- arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/vmx/pmu_intel.c | 18 ++++++++++++++---- 2 files changed, 15 insertions(+), 4 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index ede45c923089..fd1c69371dbf 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -503,6 +503,7 @@ struct kvm_pmc { u64 counter; u64 prev_counter; u64 eventsel; + u64 eventsel_hw; struct perf_event *perf_event; struct kvm_vcpu *vcpu; /* diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index 621922005184..92c5baed8d36 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -458,7 +458,18 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) if (data & reserved_bits) return 1; - if (data != pmc->eventsel) { + if (is_passthrough_pmu_enabled(vcpu)) { + pmc->eventsel = data; + if (!check_pmu_event_filter(pmc)) { + /* When guest request an invalid event, + * stop the counter by clearing the + * event selector MSR. + */ + pmc->eventsel_hw = 0; + return 0; + } + pmc->eventsel_hw = data; + } else if (data != pmc->eventsel) { pmc->eventsel = data; kvm_pmu_request_counter_reprogram(pmc); } @@ -843,13 +854,12 @@ static void intel_save_pmu_context(struct kvm_vcpu *vcpu) for (i = 0; i < pmu->nr_arch_gp_counters; i++) { pmc = &pmu->gp_counters[i]; rdpmcl(i, pmc->counter); - rdmsrl(i + MSR_ARCH_PERFMON_EVENTSEL0, pmc->eventsel); /* * Clear hardware PERFMON_EVENTSELx and its counter to avoid * leakage and also avoid this guest GP counter get accidentally * enabled during host running when host enable global ctrl. */ - if (pmc->eventsel) + if (pmc->eventsel_hw) wrmsrl(MSR_ARCH_PERFMON_EVENTSEL0 + i, 0); if (pmc->counter) wrmsrl(MSR_IA32_PMC0 + i, 0); @@ -894,7 +904,7 @@ static void intel_restore_pmu_context(struct kvm_vcpu *vcpu) for (i = 0; i < pmu->nr_arch_gp_counters; i++) { pmc = &pmu->gp_counters[i]; wrmsrl(MSR_IA32_PMC0 + i, pmc->counter); - wrmsrl(MSR_ARCH_PERFMON_EVENTSEL0 + i, pmc->eventsel); + wrmsrl(MSR_ARCH_PERFMON_EVENTSEL0 + i, pmc->eventsel_hw); } /*