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 <[email protected]> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index 81bae121a4fe..08b6a021b84e 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -83,6 +83,7 @@ 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 df17683a3b12..1004e1edf24f 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 89a76af342c8..a69c95e1f5e2 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -413,6 +413,13 @@ 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); @@ -455,6 +462,7 @@ 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 022fe2e24f82..6ea0f1d475bb 100644 --- a/arch/arm64/kvm/hyp/nvhe/trace.c +++ b/arch/arm64/kvm/hyp/nvhe/trace.c @@ -284,12 +284,20 @@ static int rb_page_init(struct hyp_buffer_page *bpage, unsigned long hva) return 0; } +static void rb_page_reset(struct hyp_buffer_page *bpage) +{ + bpage->write = 0; + bpage->entries = 0; + + local_set(&bpage->page->commit, 0); +} + static bool rb_cpu_loaded(struct hyp_rb_per_cpu *cpu_buffer) { return !!cpu_buffer->bpages; } -static void rb_cpu_disable_writing(struct hyp_rb_per_cpu *cpu_buffer) +static int rb_cpu_disable_writing(struct hyp_rb_per_cpu *cpu_buffer) { int prev_status; @@ -299,6 +307,8 @@ static void rb_cpu_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 rb_cpu_enable_writing(struct hyp_rb_per_cpu *cpu_buffer) @@ -311,6 +321,38 @@ static int rb_cpu_enable_writing(struct hyp_rb_per_cpu *cpu_buffer) return 0; } +static int rb_cpu_reset(struct hyp_rb_per_cpu *cpu_buffer) +{ + struct hyp_buffer_page *bpage; + int prev_status; + + if (!rb_cpu_loaded(cpu_buffer)) + return -ENODEV; + + prev_status = rb_cpu_disable_writing(cpu_buffer); + + bpage = cpu_buffer->head_page; + do { + rb_page_reset(bpage); + bpage = rb_next_page(bpage); + } while (bpage != cpu_buffer->head_page); + + rb_page_reset(cpu_buffer->reader_page); + + 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) + rb_cpu_enable_writing(cpu_buffer); + + return 0; +} + static void rb_cpu_teardown(struct hyp_rb_per_cpu *cpu_buffer) { int i; @@ -602,3 +644,17 @@ 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 = rb_cpu_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 3d2a58977442..7c9548bef8f8 100644 --- a/arch/arm64/kvm/hyp_trace.c +++ b/arch/arm64/kvm/hyp_trace.c @@ -206,6 +206,11 @@ 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; @@ -364,6 +369,7 @@ 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; @@ -828,6 +834,49 @@ 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"); @@ -860,6 +909,9 @@ 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); @@ -885,6 +937,9 @@ 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; -- 2.47.1.613.gc27f4b7a9f-goog
