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From: Xiong Zhang <xiong.y.zhang@linux.intel.com>
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
Subject: [RFC PATCH 09/41] perf: core/x86: Forbid PMI handler when guest own PMU
Date: Fri, 26 Jan 2024 16:54:12 +0800	[thread overview]
Message-ID: <20240126085444.324918-10-xiong.y.zhang@linux.intel.com> (raw)
In-Reply-To: <20240126085444.324918-1-xiong.y.zhang@linux.intel.com>

From: Mingwei Zhang <mizhang@google.com>

If a guest PMI is delivered after VM-exit, the KVM maskable interrupt will
be held pending until EFLAGS.IF is set. In the meantime, if the logical
processor receives an NMI for any reason at all, perf_event_nmi_handler()
will be invoked. If there is any active perf event anywhere on the system,
x86_pmu_handle_irq() will be invoked, and it will clear
IA32_PERF_GLOBAL_STATUS. By the time KVM's PMI handler is invoked, it will
be a mystery which counter(s) overflowed.

When LVTPC is using KVM PMI vecotr, PMU is owned by guest, Host NMI let
x86_pmu_handle_irq() run, x86_pmu_handle_irq() restore PMU vector to NMI
and clear IA32_PERF_GLOBAL_STATUS, this breaks guest vPMU passthrough
environment.

So modify perf_event_nmi_handler() to check perf_is_in_guest_pasthrough(),
and if so, to simply return without calling x86_pmu_handle_irq().

Suggested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
---
 arch/x86/events/core.c     | 17 +++++++++++++++++
 include/linux/perf_event.h |  1 +
 kernel/events/core.c       |  5 +++++
 3 files changed, 23 insertions(+)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index ece042cfb470..20a5ccc641b9 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -1752,6 +1752,23 @@ perf_event_nmi_handler(unsigned int cmd, struct pt_regs *regs)
 	u64 finish_clock;
 	int ret;
 
+	/*
+	 * When PMU is pass-through into guest, this handler should be forbidden from
+	 * running, the reasons are:
+	 * 1. After perf_guest_switch_to_kvm_pmi_vector() is called, and before cpu
+	 *    enter into non-root mode, NMI could happen, but x86_pmu_handle_irq()
+	 *    restore PMU to use NMI vector, which destroy KVM PMI vector setting.
+	 * 2. When VM is running, host NMI other than PMI causes VM exit, KVM will
+	 *    call host NMI handler (vmx_vcpu_enter_exit()) first before KVM save
+	 *    guest PMU context (kvm_pmu_save_pmu_context()), as x86_pmu_handle_irq()
+	 *    clear global_status MSR which has guest status now, then this destroy
+	 *    guest PMU status.
+	 * 3. After VM exit, but before KVM save guest PMU context, host NMI other
+	 *    than PMI could happen, x86_pmu_handle_irq() clear global_status MSR
+	 *    which has guest status now, then this destroy guest PMU status.
+	 */
+	if (perf_is_in_guest_passthrough())
+		return 0;
 	/*
 	 * All PMUs/events that share this PMI handler should make sure to
 	 * increment active_events for their events.
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 9912d1112371..6cfa0f5ac120 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1716,6 +1716,7 @@ extern int perf_event_period(struct perf_event *event, u64 value);
 extern u64 perf_event_pause(struct perf_event *event, bool reset);
 extern void perf_guest_enter(void);
 extern void perf_guest_exit(void);
+extern bool perf_is_in_guest_passthrough(void);
 #else /* !CONFIG_PERF_EVENTS: */
 static inline void *
 perf_aux_output_begin(struct perf_output_handle *handle,
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 59471eeec7e4..00ea2705444e 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -5848,6 +5848,11 @@ void perf_guest_exit(void)
 }
 EXPORT_SYMBOL_GPL(perf_guest_exit);
 
+bool perf_is_in_guest_passthrough(void)
+{
+	return __this_cpu_read(__perf_force_exclude_guest);
+}
+
 static inline int perf_force_exclude_guest_check(struct perf_event *event,
 						 int cpu, struct task_struct *task)
 {
-- 
2.34.1


  parent reply	other threads:[~2024-01-26  8:56 UTC|newest]

Thread overview: 181+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-26  8:54 [RFC PATCH 00/41] KVM: x86/pmu: Introduce passthrough vPM Xiong Zhang
2024-01-26  8:54 ` [RFC PATCH 01/41] perf: x86/intel: Support PERF_PMU_CAP_VPMU_PASSTHROUGH Xiong Zhang
2024-04-11 17:04   ` Sean Christopherson
2024-04-11 17:21     ` Liang, Kan
2024-04-11 17:24       ` Jim Mattson
2024-04-11 17:46         ` Sean Christopherson
2024-04-11 19:13           ` Liang, Kan
2024-04-11 20:43             ` Sean Christopherson
2024-04-11 21:04               ` Liang, Kan
2024-04-11 19:32           ` Sean Christopherson
2024-01-26  8:54 ` [RFC PATCH 02/41] perf: Support guest enter/exit interfaces Xiong Zhang
2024-03-20 16:40   ` Raghavendra Rao Ananta
2024-03-20 17:12     ` Liang, Kan
2024-04-11 18:06   ` Sean Christopherson
2024-04-11 19:53     ` Liang, Kan
2024-04-12 19:17       ` Sean Christopherson
2024-04-12 20:56         ` Liang, Kan
2024-04-15 16:03           ` Liang, Kan
2024-04-16  5:34             ` Zhang, Xiong Y
2024-04-16 12:48               ` Liang, Kan
2024-04-17  9:42                 ` Zhang, Xiong Y
2024-04-18 16:11                   ` Sean Christopherson
2024-04-19  1:37                     ` Zhang, Xiong Y
2024-04-26  4:09       ` Zhang, Xiong Y
2024-01-26  8:54 ` [RFC PATCH 03/41] perf: Set exclude_guest onto nmi_watchdog Xiong Zhang
2024-04-11 18:56   ` Sean Christopherson
2024-01-26  8:54 ` [RFC PATCH 04/41] perf: core/x86: Add support to register a new vector for PMI handling Xiong Zhang
2024-04-11 17:10   ` Sean Christopherson
2024-04-11 19:05     ` Sean Christopherson
2024-04-12  3:56     ` Zhang, Xiong Y
2024-04-13  1:17       ` Mi, Dapeng
2024-01-26  8:54 ` [RFC PATCH 05/41] KVM: x86/pmu: Register PMI handler for passthrough PMU Xiong Zhang
2024-04-11 19:07   ` Sean Christopherson
2024-04-12  5:44     ` Zhang, Xiong Y
2024-01-26  8:54 ` [RFC PATCH 06/41] perf: x86: Add function to switch PMI handler Xiong Zhang
2024-04-11 19:17   ` Sean Christopherson
2024-04-11 19:34     ` Sean Christopherson
2024-04-12  6:03       ` Zhang, Xiong Y
2024-04-12  5:57     ` Zhang, Xiong Y
2024-01-26  8:54 ` [RFC PATCH 07/41] perf/x86: Add interface to reflect virtual LVTPC_MASK bit onto HW Xiong Zhang
2024-04-11 19:21   ` Sean Christopherson
2024-04-12  6:17     ` Zhang, Xiong Y
2024-01-26  8:54 ` [RFC PATCH 08/41] KVM: x86/pmu: Add get virtual LVTPC_MASK bit function Xiong Zhang
2024-04-11 19:22   ` Sean Christopherson
2024-01-26  8:54 ` Xiong Zhang [this message]
2024-04-11 19:26   ` [RFC PATCH 09/41] perf: core/x86: Forbid PMI handler when guest own PMU Sean Christopherson
2024-01-26  8:54 ` [RFC PATCH 10/41] perf: core/x86: Plumb passthrough PMU capability from x86_pmu to x86_pmu_cap Xiong Zhang
2024-01-26  8:54 ` [RFC PATCH 11/41] KVM: x86/pmu: Introduce enable_passthrough_pmu module parameter and propage to KVM instance Xiong Zhang
2024-04-11 20:54   ` Sean Christopherson
2024-04-11 21:03   ` Sean Christopherson
2024-01-26  8:54 ` [RFC PATCH 12/41] KVM: x86/pmu: Plumb through passthrough PMU to vcpu for Intel CPUs Xiong Zhang
2024-04-11 20:57   ` Sean Christopherson
2024-01-26  8:54 ` [RFC PATCH 13/41] KVM: x86/pmu: Add a helper to check if passthrough PMU is enabled Xiong Zhang
2024-01-26  8:54 ` [RFC PATCH 14/41] KVM: x86/pmu: Allow RDPMC pass through Xiong Zhang
2024-01-26  8:54 ` [RFC PATCH 15/41] KVM: x86/pmu: Manage MSR interception for IA32_PERF_GLOBAL_CTRL Xiong Zhang
2024-04-11 21:21   ` Sean Christopherson
2024-04-11 22:30     ` Jim Mattson
2024-04-11 23:27       ` Sean Christopherson
2024-04-13  2:10       ` Mi, Dapeng
2024-01-26  8:54 ` [RFC PATCH 16/41] KVM: x86/pmu: Create a function prototype to disable MSR interception Xiong Zhang
2024-01-26  8:54 ` [RFC PATCH 17/41] KVM: x86/pmu: Implement pmu function for Intel CPU " Xiong Zhang
2024-01-26  8:54 ` [RFC PATCH 18/41] KVM: x86/pmu: Intercept full-width GP counter MSRs by checking with perf capabilities Xiong Zhang
2024-04-11 21:23   ` Sean Christopherson
2024-04-11 21:50     ` Jim Mattson
2024-04-12 16:01       ` Sean Christopherson
2024-01-26  8:54 ` [RFC PATCH 19/41] KVM: x86/pmu: Whitelist PMU MSRs for passthrough PMU Xiong Zhang
2024-01-26  8:54 ` [RFC PATCH 20/41] KVM: x86/pmu: Introduce PMU operation prototypes for save/restore PMU context Xiong Zhang
2024-01-26  8:54 ` [RFC PATCH 21/41] KVM: x86/pmu: Introduce function prototype for Intel CPU to " Xiong Zhang
2024-01-26  8:54 ` [RFC PATCH 22/41] x86: Introduce MSR_CORE_PERF_GLOBAL_STATUS_SET for passthrough PMU Xiong Zhang
2024-01-26  8:54 ` [RFC PATCH 23/41] KVM: x86/pmu: Implement the save/restore of PMU state for Intel CPU Xiong Zhang
2024-04-11 21:26   ` Sean Christopherson
2024-04-13  2:29     ` Mi, Dapeng
2024-04-11 21:44   ` Sean Christopherson
2024-04-11 22:19     ` Jim Mattson
2024-04-11 23:31       ` Sean Christopherson
2024-04-13  3:19         ` Mi, Dapeng
2024-04-13  3:03     ` Mi, Dapeng
2024-04-13  3:34       ` Mingwei Zhang
2024-04-13  4:25         ` Mi, Dapeng
2024-04-15  6:06           ` Mingwei Zhang
2024-04-15 10:04             ` Mi, Dapeng
2024-04-15 16:44               ` Mingwei Zhang
2024-04-15 17:38                 ` Sean Christopherson
2024-04-15 17:54                   ` Mingwei Zhang
2024-04-15 22:45                     ` Sean Christopherson
2024-04-22  2:14                       ` maobibo
2024-04-22 17:01                         ` Sean Christopherson
2024-04-23  1:01                           ` maobibo
2024-04-23  2:44                             ` Mi, Dapeng
2024-04-23  2:53                               ` maobibo
2024-04-23  3:13                                 ` Mi, Dapeng
2024-04-23  3:26                                   ` maobibo
2024-04-23  3:59                                     ` Mi, Dapeng
2024-04-23  3:55                                   ` maobibo
2024-04-23  4:23                                     ` Mingwei Zhang
2024-04-23  6:08                                       ` maobibo
2024-04-23  6:45                                         ` Mi, Dapeng
2024-04-23  7:10                                           ` Mingwei Zhang
2024-04-23  8:24                                             ` Mi, Dapeng
2024-04-23  8:51                                               ` maobibo
2024-04-23 16:50                                               ` Mingwei Zhang
2024-04-23 12:12                                       ` maobibo
2024-04-23 17:02                                         ` Mingwei Zhang
2024-04-24  1:07                                           ` maobibo
2024-04-24  8:18                                           ` Mi, Dapeng
2024-04-24 15:00                                             ` Sean Christopherson
2024-04-25  3:55                                               ` Mi, Dapeng
2024-04-25  4:24                                                 ` Mingwei Zhang
2024-04-25 16:13                                                   ` Liang, Kan
2024-04-25 20:16                                                     ` Mingwei Zhang
2024-04-25 20:43                                                       ` Liang, Kan
2024-04-25 21:46                                                         ` Sean Christopherson
2024-04-26  1:46                                                           ` Mi, Dapeng
2024-04-26  3:12                                                             ` Mingwei Zhang
2024-04-26  4:02                                                               ` Mi, Dapeng
2024-04-26  4:46                                                                 ` Mingwei Zhang
2024-04-26 14:09                                                               ` Liang, Kan
2024-04-26 18:41                                                                 ` Mingwei Zhang
2024-04-26 19:06                                                                   ` Liang, Kan
2024-04-26 19:46                                                                     ` Sean Christopherson
2024-04-27  3:04                                                                       ` Mingwei Zhang
2024-04-28  0:58                                                                         ` Mi, Dapeng
2024-04-28  6:01                                                                           ` Mingwei Zhang
2024-04-29 17:44                                                                             ` Sean Christopherson
2024-05-01 17:43                                                                               ` Mingwei Zhang
2024-05-01 18:00                                                                                 ` Liang, Kan
2024-05-01 20:36                                                                                 ` Sean Christopherson
2024-04-29 13:08                                                                         ` Liang, Kan
2024-04-26 13:53                                                           ` Liang, Kan
2024-04-26  1:50                                                         ` Mi, Dapeng
2024-04-18 21:21                   ` Mingwei Zhang
2024-04-18 21:41                     ` Mingwei Zhang
2024-04-19  1:02                     ` Mi, Dapeng
2024-01-26  8:54 ` [RFC PATCH 24/41] KVM: x86/pmu: Zero out unexposed Counters/Selectors to avoid information leakage Xiong Zhang
2024-04-11 21:36   ` Sean Christopherson
2024-04-11 21:56     ` Jim Mattson
2024-01-26  8:54 ` [RFC PATCH 25/41] KVM: x86/pmu: Introduce macro PMU_CAP_PERF_METRICS Xiong Zhang
2024-01-26  8:54 ` [RFC PATCH 26/41] KVM: x86/pmu: Add host_perf_cap field in kvm_caps to record host PMU capability Xiong Zhang
2024-04-11 21:49   ` Sean Christopherson
2024-01-26  8:54 ` [RFC PATCH 27/41] KVM: x86/pmu: Clear PERF_METRICS MSR for guest Xiong Zhang
2024-04-11 21:50   ` Sean Christopherson
2024-04-13  3:29     ` Mi, Dapeng
2024-01-26  8:54 ` [RFC PATCH 28/41] KVM: x86/pmu: Switch IA32_PERF_GLOBAL_CTRL at VM boundary Xiong Zhang
2024-04-11 21:54   ` Sean Christopherson
2024-04-11 22:10     ` Jim Mattson
2024-04-11 22:54       ` Sean Christopherson
2024-04-11 23:08         ` Jim Mattson
2024-01-26  8:54 ` [RFC PATCH 29/41] KVM: x86/pmu: Exclude existing vLBR logic from the passthrough PMU Xiong Zhang
2024-01-26  8:54 ` [RFC PATCH 30/41] KVM: x86/pmu: Switch PMI handler at KVM context switch boundary Xiong Zhang
2024-01-26  8:54 ` [RFC PATCH 31/41] KVM: x86/pmu: Call perf_guest_enter() at PMU context switch Xiong Zhang
2024-01-26  8:54 ` [RFC PATCH 32/41] KVM: x86/pmu: Add support for PMU context switch at VM-exit/enter Xiong Zhang
2024-01-26  8:54 ` [RFC PATCH 33/41] KVM: x86/pmu: Make check_pmu_event_filter() an exported function Xiong Zhang
2024-01-26  8:54 ` [RFC PATCH 34/41] KVM: x86/pmu: Intercept EVENT_SELECT MSR Xiong Zhang
2024-04-11 21:55   ` Sean Christopherson
2024-01-26  8:54 ` [RFC PATCH 35/41] KVM: x86/pmu: Allow writing to event selector for GP counters if event is allowed Xiong Zhang
2024-01-26  8:54 ` [RFC PATCH 36/41] KVM: x86/pmu: Intercept FIXED_CTR_CTRL MSR Xiong Zhang
2024-04-11 21:56   ` Sean Christopherson
2024-01-26  8:54 ` [RFC PATCH 37/41] KVM: x86/pmu: Allow writing to fixed counter selector if counter is exposed Xiong Zhang
2024-04-11 22:03   ` Sean Christopherson
2024-04-13  4:12     ` Mi, Dapeng
2024-01-26  8:54 ` [RFC PATCH 38/41] KVM: x86/pmu: Introduce PMU helper to increment counter Xiong Zhang
2024-01-26  8:54 ` [RFC PATCH 39/41] KVM: x86/pmu: Implement emulated counter increment for passthrough PMU Xiong Zhang
2024-04-11 23:12   ` Sean Christopherson
2024-04-11 23:17     ` Sean Christopherson
2024-01-26  8:54 ` [RFC PATCH 40/41] KVM: x86/pmu: Separate passthrough PMU logic in set/get_msr() from non-passthrough vPMU Xiong Zhang
2024-04-11 23:18   ` Sean Christopherson
2024-04-18 21:54     ` Mingwei Zhang
2024-01-26  8:54 ` [RFC PATCH 41/41] KVM: nVMX: Add nested virtualization support for passthrough PMU Xiong Zhang
2024-04-11 23:21   ` Sean Christopherson
2024-04-11 17:03 ` [RFC PATCH 00/41] KVM: x86/pmu: Introduce passthrough vPM Sean Christopherson
2024-04-12  2:19   ` Zhang, Xiong Y
2024-04-12 18:32     ` Sean Christopherson
2024-04-15  1:06       ` Zhang, Xiong Y
2024-04-15 15:05         ` Sean Christopherson
2024-04-16  5:11           ` Zhang, Xiong Y
2024-04-18 20:46   ` Mingwei Zhang
2024-04-18 21:52     ` Mingwei Zhang
2024-04-19 19:14     ` Sean Christopherson
2024-04-19 22:02       ` Mingwei Zhang
2024-04-11 23:25 ` Sean Christopherson
2024-04-11 23:56   ` Mingwei Zhang

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