From: Sean Christopherson <seanjc@google.com>
To: Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Marc Zyngier <maz@kernel.org>, Guo Ren <guoren@kernel.org>,
Nick Hu <nickhu@andestech.com>, Greentime Hu <green.hu@gmail.com>,
Vincent Chen <deanbo422@gmail.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>,
x86@kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
James Morse <james.morse@arm.com>,
Alexandru Elisei <alexandru.elisei@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Stefano Stabellini <sstabellini@kernel.org>,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, linux-csky@vger.kernel.org,
linux-riscv@lists.infradead.org, kvm@vger.kernel.org,
xen-devel@lists.xenproject.org,
Artem Kashkanov <artem.kashkanov@intel.com>,
Like Xu <like.xu.linux@gmail.com>,
Zhu Lingshan <lingshan.zhu@intel.com>
Subject: [PATCH 14/15] perf: Disallow bulk unregistering of guest callbacks and do cleanup
Date: Thu, 26 Aug 2021 17:57:17 -0700 [thread overview]
Message-ID: <20210827005718.585190-15-seanjc@google.com> (raw)
In-Reply-To: <20210827005718.585190-1-seanjc@google.com>
Drop the helper that allows bulk unregistering of the per-CPU callbacks
now that KVM, the only entity that actually unregisters callbacks, uses
the per-CPU helpers. Bulk unregistering is inherently unsafe as there
are no protections against nullifying a pointer for a CPU that is using
said pointer in a PMI handler.
Opportunistically tweak names to better reflect reality.
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/xen/pmu.c | 2 +-
include/linux/kvm_host.h | 2 +-
include/linux/perf_event.h | 9 +++------
kernel/events/core.c | 31 +++++++++++--------------------
virt/kvm/kvm_main.c | 2 +-
5 files changed, 17 insertions(+), 29 deletions(-)
diff --git a/arch/x86/xen/pmu.c b/arch/x86/xen/pmu.c
index e13b0b49fcdf..57834de043c3 100644
--- a/arch/x86/xen/pmu.c
+++ b/arch/x86/xen/pmu.c
@@ -548,7 +548,7 @@ void xen_pmu_init(int cpu)
per_cpu(xenpmu_shared, cpu).flags = 0;
if (cpu == 0) {
- perf_register_guest_info_callbacks(&xen_guest_cbs);
+ perf_register_guest_info_callbacks_all_cpus(&xen_guest_cbs);
xen_pmu_arch_init();
}
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 0db9af0b628c..d68a49d5fc53 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1171,7 +1171,7 @@ unsigned long kvm_arch_vcpu_get_ip(struct kvm_vcpu *vcpu);
void kvm_register_perf_callbacks(void);
static inline void kvm_unregister_perf_callbacks(void)
{
- __perf_unregister_guest_info_callbacks();
+ perf_unregister_guest_info_callbacks();
}
#endif
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 7a367bf1b78d..db701409a62f 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1238,10 +1238,9 @@ extern void perf_event_bpf_event(struct bpf_prog *prog,
#ifdef CONFIG_HAVE_GUEST_PERF_EVENTS
DECLARE_PER_CPU(struct perf_guest_info_callbacks *, perf_guest_cbs);
-extern void __perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs);
-extern void __perf_unregister_guest_info_callbacks(void);
-extern void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *callbacks);
+extern void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs);
extern void perf_unregister_guest_info_callbacks(void);
+extern void perf_register_guest_info_callbacks_all_cpus(struct perf_guest_info_callbacks *cbs);
#endif /* CONFIG_HAVE_GUEST_PERF_EVENTS */
extern void perf_event_exec(void);
@@ -1486,9 +1485,7 @@ static inline void
perf_bp_event(struct perf_event *event, void *data) { }
#ifdef CONFIG_HAVE_GUEST_PERF_EVENTS
-static inline void perf_register_guest_info_callbacks
-(struct perf_guest_info_callbacks *callbacks) { }
-static inline void perf_unregister_guest_info_callbacks(void) { }
+extern void perf_register_guest_info_callbacks_all_cpus(struct perf_guest_info_callbacks *cbs);
#endif
static inline void perf_event_mmap(struct vm_area_struct *vma) { }
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 2f28d9d8dc94..f1964096c4c2 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6485,35 +6485,26 @@ static void perf_pending_event(struct irq_work *entry)
#ifdef CONFIG_HAVE_GUEST_PERF_EVENTS
DEFINE_PER_CPU(struct perf_guest_info_callbacks *, perf_guest_cbs);
-void __perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
-{
- __this_cpu_write(perf_guest_cbs, cbs);
-}
-EXPORT_SYMBOL_GPL(__perf_register_guest_info_callbacks);
-
-void __perf_unregister_guest_info_callbacks(void)
-{
- __this_cpu_write(perf_guest_cbs, NULL);
-}
-EXPORT_SYMBOL_GPL(__perf_unregister_guest_info_callbacks);
-
void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
{
- int cpu;
-
- for_each_possible_cpu(cpu)
- per_cpu(perf_guest_cbs, cpu) = cbs;
+ __this_cpu_write(perf_guest_cbs, cbs);
}
EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
void perf_unregister_guest_info_callbacks(void)
{
- int cpu;
-
- for_each_possible_cpu(cpu)
- per_cpu(perf_guest_cbs, cpu) = NULL;
+ __this_cpu_write(perf_guest_cbs, NULL);
}
EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
+
+void perf_register_guest_info_callbacks_all_cpus(struct perf_guest_info_callbacks *cbs)
+{
+ int cpu;
+
+ for_each_possible_cpu(cpu)
+ per_cpu(perf_guest_cbs, cpu) = cbs;
+}
+EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks_all_cpus);
#endif
static void
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index e0b1c9386926..1bcc3eab510b 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -5502,7 +5502,7 @@ EXPORT_SYMBOL_GPL(kvm_set_intel_pt_intr_handler);
void kvm_register_perf_callbacks(void)
{
- __perf_register_guest_info_callbacks(&kvm_guest_cbs);
+ perf_register_guest_info_callbacks(&kvm_guest_cbs);
}
EXPORT_SYMBOL_GPL(kvm_register_perf_callbacks);
#endif
--
2.33.0.259.gc128427fd7-goog
next prev parent reply other threads:[~2021-08-27 0:59 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-27 0:57 [PATCH 00/15] perf: KVM: Fix, optimize, and clean up callbacks Sean Christopherson
2021-08-27 0:57 ` [PATCH 01/15] KVM: x86: Register perf callbacks after calling vendor's hardware_setup() Sean Christopherson
2021-08-27 0:57 ` [PATCH 02/15] KVM: x86: Register Processor Trace interrupt hook iff PT enabled in guest Sean Christopherson
2021-08-27 0:57 ` [PATCH 03/15] perf: Stop pretending that perf can handle multiple guest callbacks Sean Christopherson
2021-08-27 0:57 ` [PATCH 04/15] perf: Force architectures to opt-in to " Sean Christopherson
2021-08-27 0:57 ` [PATCH 05/15] perf: Track guest callbacks on a per-CPU basis Sean Christopherson
2021-08-27 7:15 ` Peter Zijlstra
2021-08-27 14:49 ` Sean Christopherson
2021-08-27 14:56 ` Peter Zijlstra
2021-08-27 15:22 ` Sean Christopherson
2021-08-27 0:57 ` [PATCH 06/15] KVM: x86: Register perf callbacks only when actively handling interrupt Sean Christopherson
2021-08-27 7:21 ` Peter Zijlstra
2021-08-27 0:57 ` [PATCH 07/15] KVM: Use dedicated flag to track if KVM is handling an NMI from guest Sean Christopherson
2021-08-27 7:30 ` Peter Zijlstra
2021-08-27 14:58 ` Sean Christopherson
2021-08-27 0:57 ` [PATCH 08/15] KVM: x86: Drop current_vcpu in favor of kvm_running_vcpu Sean Christopherson
2021-08-27 0:57 ` [PATCH 09/15] KVM: arm64: Register/unregister perf callbacks at vcpu load/put Sean Christopherson
2021-08-27 0:57 ` [PATCH 10/15] KVM: Move x86's perf guest info callbacks to generic KVM Sean Christopherson
2021-08-27 0:57 ` [PATCH 11/15] KVM: x86: Move Intel Processor Trace interrupt handler to vmx.c Sean Christopherson
2021-08-27 7:34 ` Peter Zijlstra
2021-08-27 0:57 ` [PATCH 12/15] KVM: arm64: Convert to the generic perf callbacks Sean Christopherson
2021-08-27 0:57 ` [PATCH 13/15] KVM: arm64: Drop perf.c and fold its tiny bit of code into pmu.c Sean Christopherson
2021-08-27 0:57 ` Sean Christopherson [this message]
2021-08-27 0:57 ` [PATCH 15/15] perf: KVM: Indicate "in guest" via NULL ->is_in_guest callback Sean Christopherson
2021-08-27 6:52 ` [PATCH 00/15] perf: KVM: Fix, optimize, and clean up callbacks Like Xu
2021-08-27 7:44 ` Peter Zijlstra
2021-08-27 8:01 ` Like Xu
2021-08-27 10:47 ` Peter Zijlstra
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