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AJvYcCXZYlsoKutIb9fQGjtVVHN9EeAN/1K2QjkvlE4/5pmO34xw5j4N+Sc9ngPDN6ZgD6LJ+ZTo/2Wft2fbwD12A3VM1YY=@vger.kernel.org X-Gm-Message-State: AOJu0Yzjx2qZndz10pv4m/NxdCeE34lUF+8LCc7/HLdj66IZfCPrpvod rTSDuyL70yZOKCDw2uNMl8vw+Uo8UjFVqLwp1xnpVdftCV8HEII6dT9ieckUBovhNZk/EaF+9id 54WXhUni4Q8WFur27Nw== X-Google-Smtp-Source: AGHT+IEfGb128a2DZBA8iW3Df9rmq3CoqidzScBKQXE2CAExXpW8soetaBJWs+nYkO8TCElzGRor5RI3Vx2qFvd6 X-Received: from wrbgx18.prod.google.com ([2002:a05:6000:4712:b0:38f:478d:618d]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a5d:45c5:0:b0:38d:e0be:71a3 with SMTP id ffacd0b85a97d-38f708593a9mr7968419f8f.54.1740399342646; Mon, 24 Feb 2025 04:15:42 -0800 (PST) Date: Mon, 24 Feb 2025 12:13:51 +0000 In-Reply-To: <20250224121353.98697-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250224121353.98697-1-vdonnefort@google.com> X-Mailer: git-send-email 2.48.1.601.g30ceb7b040-goog Message-ID: <20250224121353.98697-10-vdonnefort@google.com> Subject: [PATCH 09/11] KVM: arm64: Add trace interface for hyp tracefs From: Vincent Donnefort To: rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, linux-trace-kernel@vger.kernel.org, maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, jstultz@google.com, qperret@google.com, will@kernel.org, kernel-team@android.com, linux-kernel@vger.kernel.org, Vincent Donnefort The trace interface is solely here to reset tracing. Non-consuming read is not yet supported due to the lack of support in the ring-buffer meta page. Signed-off-by: Vincent Donnefort diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index 87d3e0e73b68..74f10847a55e 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -91,6 +91,7 @@ enum __kvm_host_smccc_func { __KVM_HOST_SMCCC_FUNC___pkvm_load_tracing, __KVM_HOST_SMCCC_FUNC___pkvm_teardown_tracing, __KVM_HOST_SMCCC_FUNC___pkvm_enable_tracing, + __KVM_HOST_SMCCC_FUNC___pkvm_reset_tracing, __KVM_HOST_SMCCC_FUNC___pkvm_swap_reader_tracing, }; diff --git a/arch/arm64/kvm/hyp/include/nvhe/trace.h b/arch/arm64/kvm/hyp/include/nvhe/trace.h index 6f1cc571b47a..28bbb54b7a0b 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/trace.h +++ b/arch/arm64/kvm/hyp/include/nvhe/trace.h @@ -20,6 +20,7 @@ void __pkvm_update_clock_tracing(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cy int __pkvm_load_tracing(unsigned long desc_va, size_t desc_size); void __pkvm_teardown_tracing(void); int __pkvm_enable_tracing(bool enable); +int __pkvm_reset_tracing(unsigned int cpu); int __pkvm_swap_reader_tracing(unsigned int cpu); #else static inline void *tracing_reserve_entry(unsigned long length) { return NULL; } @@ -30,6 +31,7 @@ void __pkvm_update_clock_tracing(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cy static inline int __pkvm_load_tracing(unsigned long desc_va, size_t desc_size) { return -ENODEV; } static inline void __pkvm_teardown_tracing(void) { } static inline int __pkvm_enable_tracing(bool enable) { return -ENODEV; } +static inline int __pkvm_reset_tracing(unsigned int cpu) { return -ENODEV; } static inline int __pkvm_swap_reader_tracing(unsigned int cpu) { return -ENODEV; } #endif #endif diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c index a8b497b22407..e2419c97c57d 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -605,6 +605,13 @@ static void handle___pkvm_enable_tracing(struct kvm_cpu_context *host_ctxt) cpu_reg(host_ctxt, 1) = __pkvm_enable_tracing(enable); } +static void handle___pkvm_reset_tracing(struct kvm_cpu_context *host_ctxt) +{ + DECLARE_REG(unsigned int, cpu, host_ctxt, 1); + + cpu_reg(host_ctxt, 1) = __pkvm_reset_tracing(cpu); +} + static void handle___pkvm_swap_reader_tracing(struct kvm_cpu_context *host_ctxt) { DECLARE_REG(unsigned int, cpu, host_ctxt, 1); @@ -655,6 +662,7 @@ static const hcall_t host_hcall[] = { HANDLE_FUNC(__pkvm_load_tracing), HANDLE_FUNC(__pkvm_teardown_tracing), HANDLE_FUNC(__pkvm_enable_tracing), + HANDLE_FUNC(__pkvm_reset_tracing), HANDLE_FUNC(__pkvm_swap_reader_tracing), }; diff --git a/arch/arm64/kvm/hyp/nvhe/trace.c b/arch/arm64/kvm/hyp/nvhe/trace.c index d79b6539377e..bf935645ed91 100644 --- a/arch/arm64/kvm/hyp/nvhe/trace.c +++ b/arch/arm64/kvm/hyp/nvhe/trace.c @@ -262,7 +262,7 @@ void tracing_commit_entry(void) smp_store_release(&cpu_buffer->status, HYP_RB_READY); } -static void hyp_rb_disable_writing(struct hyp_rb_per_cpu *cpu_buffer) +static u32 hyp_rb_disable_writing(struct hyp_rb_per_cpu *cpu_buffer) { u32 prev_status; @@ -272,6 +272,8 @@ static void hyp_rb_disable_writing(struct hyp_rb_per_cpu *cpu_buffer) HYP_RB_READY, HYP_RB_UNAVAILABLE); } while (prev_status == HYP_RB_WRITING); + + return prev_status; } static int hyp_rb_enable_writing(struct hyp_rb_per_cpu *cpu_buffer) @@ -284,6 +286,44 @@ static int hyp_rb_enable_writing(struct hyp_rb_per_cpu *cpu_buffer) return 0; } +static int hyp_rb_reset(struct hyp_rb_per_cpu *cpu_buffer) +{ + struct hyp_buffer_page *bpage; + u32 prev_status; + + if (!hyp_rb_loaded(cpu_buffer)) + return -ENODEV; + + prev_status = hyp_rb_disable_writing(cpu_buffer); + + while (!hyp_bpage_is_head(cpu_buffer->head_page)) + cpu_buffer->head_page = hyp_bpage_next_page(cpu_buffer->head_page); + + bpage = cpu_buffer->tail_page = cpu_buffer->head_page; + do { + hyp_bpage_reset(bpage); + bpage = hyp_bpage_next_page(bpage); + } while (bpage != cpu_buffer->head_page); + + hyp_bpage_reset(cpu_buffer->reader_page); + + cpu_buffer->last_overrun = 0; + cpu_buffer->write_stamp = 0; + + cpu_buffer->meta->reader.read = 0; + cpu_buffer->meta->reader.lost_events = 0; + cpu_buffer->meta->entries = 0; + cpu_buffer->meta->overrun = 0; + cpu_buffer->meta->read = 0; + meta_pages_lost(cpu_buffer->meta) = 0; + meta_pages_touched(cpu_buffer->meta) = 0; + + if (prev_status == HYP_RB_READY) + hyp_rb_enable_writing(cpu_buffer); + + return 0; +} + static void hyp_rb_teardown(struct hyp_rb_per_cpu *cpu_buffer) { int i; @@ -572,3 +612,17 @@ int __pkvm_enable_tracing(bool enable) return ret; } + +int __pkvm_reset_tracing(unsigned int cpu) +{ + int ret = 0; + + if (cpu >= hyp_nr_cpus) + return -EINVAL; + + hyp_spin_lock(&trace_rb_lock); + ret = hyp_rb_reset(per_cpu_ptr(&trace_rb, cpu)); + hyp_spin_unlock(&trace_rb_lock); + + return ret; +} diff --git a/arch/arm64/kvm/hyp_trace.c b/arch/arm64/kvm/hyp_trace.c index 38d97e34eada..03a6813cbe66 100644 --- a/arch/arm64/kvm/hyp_trace.c +++ b/arch/arm64/kvm/hyp_trace.c @@ -200,6 +200,11 @@ static int __get_reader_page(int cpu) return kvm_call_hyp_nvhe(__pkvm_swap_reader_tracing, cpu); } +static int __reset(int cpu) +{ + return kvm_call_hyp_nvhe(__pkvm_reset_tracing, cpu); +} + static void hyp_trace_free_pages(struct hyp_trace_desc *desc) { struct rb_page_desc *rb_desc; @@ -361,6 +366,7 @@ static int hyp_trace_buffer_load(struct hyp_trace_buffer *hyp_buffer, size_t siz hyp_buffer->remote.pdesc = &desc->page_desc; hyp_buffer->remote.get_reader_page = __get_reader_page; + hyp_buffer->remote.reset = __reset; hyp_buffer->trace_buffer = ring_buffer_remote(&hyp_buffer->remote); if (!hyp_buffer->trace_buffer) { ret = -ENOMEM; @@ -825,6 +831,49 @@ static const struct file_operations hyp_trace_raw_fops = { .release = hyp_trace_raw_release, }; +static void hyp_trace_reset(int cpu) +{ + struct hyp_trace_buffer *hyp_buffer = &hyp_trace_buffer; + + mutex_lock(&hyp_buffer->lock); + + if (!hyp_trace_buffer_loaded(hyp_buffer)) + goto out; + + if (cpu == RING_BUFFER_ALL_CPUS) + ring_buffer_reset(hyp_buffer->trace_buffer); + else + ring_buffer_reset_cpu(hyp_buffer->trace_buffer, cpu); + +out: + mutex_unlock(&hyp_buffer->lock); +} + +static int hyp_trace_open(struct inode *inode, struct file *file) +{ + int cpu = (s64)inode->i_private; + + if (file->f_mode & FMODE_WRITE) { + hyp_trace_reset(cpu); + + return 0; + } + + return -EPERM; +} + +static ssize_t hyp_trace_write(struct file *filp, const char __user *ubuf, + size_t count, loff_t *ppos) +{ + return count; +} + +static const struct file_operations hyp_trace_fops = { + .open = hyp_trace_open, + .write = hyp_trace_write, + .release = NULL, +}; + static int hyp_trace_clock_show(struct seq_file *m, void *v) { seq_puts(m, "[boot]\n"); @@ -857,6 +906,9 @@ int hyp_trace_init_tracefs(void) tracefs_create_file("trace_pipe", TRACEFS_MODE_WRITE, root, (void *)RING_BUFFER_ALL_CPUS, &hyp_trace_pipe_fops); + tracefs_create_file("trace", TRACEFS_MODE_WRITE, root, + (void *)RING_BUFFER_ALL_CPUS, &hyp_trace_fops); + tracefs_create_file("trace_clock", TRACEFS_MODE_READ, root, NULL, &hyp_trace_clock_fops); @@ -882,6 +934,9 @@ int hyp_trace_init_tracefs(void) tracefs_create_file("trace_pipe_raw", TRACEFS_MODE_READ, per_cpu_dir, (void *)cpu, &hyp_trace_pipe_fops); + + tracefs_create_file("trace", TRACEFS_MODE_READ, per_cpu_dir, + (void *)cpu, &hyp_trace_fops); } return 0;