diff options
| -rw-r--r-- | arch/arm64/include/asm/kvm_asm.h | 4 | ||||
| -rw-r--r-- | arch/arm64/include/asm/kvm_hyptrace.h | 13 | ||||
| -rw-r--r-- | arch/arm64/kvm/Kconfig | 5 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/include/nvhe/trace.h | 23 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/nvhe/Makefile | 5 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/nvhe/hyp-main.c | 32 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/nvhe/trace.c | 273 |
7 files changed, 354 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index a1ad12c72ebf..d46d9196d661 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -89,6 +89,10 @@ enum __kvm_host_smccc_func { __KVM_HOST_SMCCC_FUNC___pkvm_vcpu_load, __KVM_HOST_SMCCC_FUNC___pkvm_vcpu_put, __KVM_HOST_SMCCC_FUNC___pkvm_tlb_flush_vmid, + __KVM_HOST_SMCCC_FUNC___tracing_load, + __KVM_HOST_SMCCC_FUNC___tracing_unload, + __KVM_HOST_SMCCC_FUNC___tracing_enable, + __KVM_HOST_SMCCC_FUNC___tracing_swap_reader, }; #define DECLARE_KVM_VHE_SYM(sym) extern char sym[] diff --git a/arch/arm64/include/asm/kvm_hyptrace.h b/arch/arm64/include/asm/kvm_hyptrace.h new file mode 100644 index 000000000000..9c30a479bc36 --- /dev/null +++ b/arch/arm64/include/asm/kvm_hyptrace.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef __ARM64_KVM_HYPTRACE_H_ +#define __ARM64_KVM_HYPTRACE_H_ + +#include <linux/ring_buffer.h> + +struct hyp_trace_desc { + unsigned long bpages_backing_start; + size_t bpages_backing_size; + struct trace_buffer_desc trace_buffer_desc; + +}; +#endif diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig index 14b2d0b0b831..d215348370fa 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -72,6 +72,11 @@ config NVHE_EL2_DEBUG if NVHE_EL2_DEBUG +config NVHE_EL2_TRACING + bool + depends on TRACING + default y + config PKVM_DISABLE_STAGE2_ON_PANIC bool "Disable the host stage-2 on panic" default n diff --git a/arch/arm64/kvm/hyp/include/nvhe/trace.h b/arch/arm64/kvm/hyp/include/nvhe/trace.h new file mode 100644 index 000000000000..7da8788ce527 --- /dev/null +++ b/arch/arm64/kvm/hyp/include/nvhe/trace.h @@ -0,0 +1,23 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef __ARM64_KVM_HYP_NVHE_TRACE_H +#define __ARM64_KVM_HYP_NVHE_TRACE_H +#include <asm/kvm_hyptrace.h> + +#ifdef CONFIG_NVHE_EL2_TRACING +void *tracing_reserve_entry(unsigned long length); +void tracing_commit_entry(void); + +int __tracing_load(unsigned long desc_va, size_t desc_size); +void __tracing_unload(void); +int __tracing_enable(bool enable); +int __tracing_swap_reader(unsigned int cpu); +#else +static inline void *tracing_reserve_entry(unsigned long length) { return NULL; } +static inline void tracing_commit_entry(void) { } + +static inline int __tracing_load(unsigned long desc_va, size_t desc_size) { return -ENODEV; } +static inline void __tracing_unload(void) { } +static inline int __tracing_enable(bool enable) { return -ENODEV; } +static inline int __tracing_swap_reader(unsigned int cpu) { return -ENODEV; } +#endif +#endif diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile index 8dc95257c291..f1840628d2d6 100644 --- a/arch/arm64/kvm/hyp/nvhe/Makefile +++ b/arch/arm64/kvm/hyp/nvhe/Makefile @@ -29,9 +29,12 @@ hyp-obj-y += ../vgic-v3-sr.o ../aarch32.o ../vgic-v2-cpuif-proxy.o ../entry.o \ ../fpsimd.o ../hyp-entry.o ../exception.o ../pgtable.o hyp-obj-y += ../../../kernel/smccc-call.o hyp-obj-$(CONFIG_LIST_HARDENED) += list_debug.o -hyp-obj-$(CONFIG_NVHE_EL2_TRACING) += clock.o +hyp-obj-$(CONFIG_NVHE_EL2_TRACING) += clock.o trace.o hyp-obj-y += $(lib-objs) +# Path to simple_ring_buffer.c +CFLAGS_trace.nvhe.o += -I$(objtree)/kernel/trace/ + ## ## Build rules for compiling nVHE hyp code ## Output of this folder is `kvm_nvhe.o`, a partially linked object diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c index 8ae3c348ed81..ae04204ea81f 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -18,6 +18,7 @@ #include <nvhe/mem_protect.h> #include <nvhe/mm.h> #include <nvhe/pkvm.h> +#include <nvhe/trace.h> #include <nvhe/trap_handler.h> DEFINE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params); @@ -587,6 +588,33 @@ static void handle___pkvm_teardown_vm(struct kvm_cpu_context *host_ctxt) cpu_reg(host_ctxt, 1) = __pkvm_teardown_vm(handle); } +static void handle___tracing_load(struct kvm_cpu_context *host_ctxt) +{ + DECLARE_REG(unsigned long, desc_hva, host_ctxt, 1); + DECLARE_REG(size_t, desc_size, host_ctxt, 2); + + cpu_reg(host_ctxt, 1) = __tracing_load(desc_hva, desc_size); +} + +static void handle___tracing_unload(struct kvm_cpu_context *host_ctxt) +{ + __tracing_unload(); +} + +static void handle___tracing_enable(struct kvm_cpu_context *host_ctxt) +{ + DECLARE_REG(bool, enable, host_ctxt, 1); + + cpu_reg(host_ctxt, 1) = __tracing_enable(enable); +} + +static void handle___tracing_swap_reader(struct kvm_cpu_context *host_ctxt) +{ + DECLARE_REG(unsigned int, cpu, host_ctxt, 1); + + cpu_reg(host_ctxt, 1) = __tracing_swap_reader(cpu); +} + typedef void (*hcall_t)(struct kvm_cpu_context *); #define HANDLE_FUNC(x) [__KVM_HOST_SMCCC_FUNC_##x] = (hcall_t)handle_##x @@ -628,6 +656,10 @@ static const hcall_t host_hcall[] = { HANDLE_FUNC(__pkvm_vcpu_load), HANDLE_FUNC(__pkvm_vcpu_put), HANDLE_FUNC(__pkvm_tlb_flush_vmid), + HANDLE_FUNC(__tracing_load), + HANDLE_FUNC(__tracing_unload), + HANDLE_FUNC(__tracing_enable), + HANDLE_FUNC(__tracing_swap_reader), }; static void handle_host_hcall(struct kvm_cpu_context *host_ctxt) diff --git a/arch/arm64/kvm/hyp/nvhe/trace.c b/arch/arm64/kvm/hyp/nvhe/trace.c new file mode 100644 index 000000000000..282cba70ce9b --- /dev/null +++ b/arch/arm64/kvm/hyp/nvhe/trace.c @@ -0,0 +1,273 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2025 Google LLC + * Author: Vincent Donnefort <vdonnefort@google.com> + */ + +#include <nvhe/clock.h> +#include <nvhe/mem_protect.h> +#include <nvhe/mm.h> +#include <nvhe/trace.h> + +#include <asm/percpu.h> +#include <asm/kvm_mmu.h> +#include <asm/local.h> + +#include "simple_ring_buffer.c" + +static DEFINE_PER_CPU(struct simple_rb_per_cpu, __simple_rbs); + +static struct hyp_trace_buffer { + struct simple_rb_per_cpu __percpu *simple_rbs; + void *bpages_backing_start; + size_t bpages_backing_size; + hyp_spinlock_t lock; +} trace_buffer = { + .simple_rbs = &__simple_rbs, + .lock = __HYP_SPIN_LOCK_UNLOCKED, +}; + +static bool hyp_trace_buffer_loaded(struct hyp_trace_buffer *trace_buffer) +{ + return trace_buffer->bpages_backing_size > 0; +} + +void *tracing_reserve_entry(unsigned long length) +{ + return simple_ring_buffer_reserve(this_cpu_ptr(trace_buffer.simple_rbs), length, + trace_clock()); +} + +void tracing_commit_entry(void) +{ + simple_ring_buffer_commit(this_cpu_ptr(trace_buffer.simple_rbs)); +} + +static int __admit_host_mem(void *start, u64 size) +{ + if (!PAGE_ALIGNED(start) || !PAGE_ALIGNED(size) || !size) + return -EINVAL; + + if (!is_protected_kvm_enabled()) + return 0; + + return __pkvm_host_donate_hyp(hyp_virt_to_pfn(start), size >> PAGE_SHIFT); +} + +static void __release_host_mem(void *start, u64 size) +{ + if (!is_protected_kvm_enabled()) + return; + + WARN_ON(__pkvm_hyp_donate_host(hyp_virt_to_pfn(start), size >> PAGE_SHIFT)); +} + +static int hyp_trace_buffer_load_bpage_backing(struct hyp_trace_buffer *trace_buffer, + struct hyp_trace_desc *desc) +{ + void *start = (void *)kern_hyp_va(desc->bpages_backing_start); + size_t size = desc->bpages_backing_size; + int ret; + + ret = __admit_host_mem(start, size); + if (ret) + return ret; + + memset(start, 0, size); + + trace_buffer->bpages_backing_start = start; + trace_buffer->bpages_backing_size = size; + + return 0; +} + +static void hyp_trace_buffer_unload_bpage_backing(struct hyp_trace_buffer *trace_buffer) +{ + void *start = trace_buffer->bpages_backing_start; + size_t size = trace_buffer->bpages_backing_size; + + if (!size) + return; + + memset(start, 0, size); + + __release_host_mem(start, size); + + trace_buffer->bpages_backing_start = 0; + trace_buffer->bpages_backing_size = 0; +} + +static void *__pin_shared_page(unsigned long kern_va) +{ + void *va = kern_hyp_va((void *)kern_va); + + if (!is_protected_kvm_enabled()) + return va; + + return hyp_pin_shared_mem(va, va + PAGE_SIZE) ? NULL : va; +} + +static void __unpin_shared_page(void *va) +{ + if (!is_protected_kvm_enabled()) + return; + + hyp_unpin_shared_mem(va, va + PAGE_SIZE); +} + +static void hyp_trace_buffer_unload(struct hyp_trace_buffer *trace_buffer) +{ + int cpu; + + hyp_assert_lock_held(&trace_buffer->lock); + + if (!hyp_trace_buffer_loaded(trace_buffer)) + return; + + for (cpu = 0; cpu < hyp_nr_cpus; cpu++) + simple_ring_buffer_unload_mm(per_cpu_ptr(trace_buffer->simple_rbs, cpu), + __unpin_shared_page); + + hyp_trace_buffer_unload_bpage_backing(trace_buffer); +} + +static int hyp_trace_buffer_load(struct hyp_trace_buffer *trace_buffer, + struct hyp_trace_desc *desc) +{ + struct simple_buffer_page *bpages; + struct ring_buffer_desc *rb_desc; + int ret, cpu; + + hyp_assert_lock_held(&trace_buffer->lock); + + if (hyp_trace_buffer_loaded(trace_buffer)) + return -EINVAL; + + ret = hyp_trace_buffer_load_bpage_backing(trace_buffer, desc); + if (ret) + return ret; + + bpages = trace_buffer->bpages_backing_start; + for_each_ring_buffer_desc(rb_desc, cpu, &desc->trace_buffer_desc) { + ret = simple_ring_buffer_init_mm(per_cpu_ptr(trace_buffer->simple_rbs, cpu), + bpages, rb_desc, __pin_shared_page, + __unpin_shared_page); + if (ret) + break; + + bpages += rb_desc->nr_page_va; + } + + if (ret) + hyp_trace_buffer_unload(trace_buffer); + + return ret; +} + +static bool hyp_trace_desc_validate(struct hyp_trace_desc *desc, size_t desc_size) +{ + struct ring_buffer_desc *rb_desc; + unsigned int cpu; + size_t nr_bpages; + void *desc_end; + + /* + * Both desc_size and bpages_backing_size are untrusted host-provided + * values. We rely on __pkvm_host_donate_hyp() to enforce their validity. + */ + desc_end = (void *)desc + desc_size; + nr_bpages = desc->bpages_backing_size / sizeof(struct simple_buffer_page); + + for_each_ring_buffer_desc(rb_desc, cpu, &desc->trace_buffer_desc) { + /* Can we read nr_page_va? */ + if ((void *)rb_desc + struct_size(rb_desc, page_va, 0) > desc_end) + return false; + + /* Overflow desc? */ + if ((void *)rb_desc + struct_size(rb_desc, page_va, rb_desc->nr_page_va) > desc_end) + return false; + + /* Overflow bpages backing memory? */ + if (nr_bpages < rb_desc->nr_page_va) + return false; + + if (cpu >= hyp_nr_cpus) + return false; + + if (cpu != rb_desc->cpu) + return false; + + nr_bpages -= rb_desc->nr_page_va; + } + + return true; +} + +int __tracing_load(unsigned long desc_hva, size_t desc_size) +{ + struct hyp_trace_desc *desc = (struct hyp_trace_desc *)kern_hyp_va(desc_hva); + int ret; + + ret = __admit_host_mem(desc, desc_size); + if (ret) + return ret; + + if (!hyp_trace_desc_validate(desc, desc_size)) + goto err_release_desc; + + hyp_spin_lock(&trace_buffer.lock); + + ret = hyp_trace_buffer_load(&trace_buffer, desc); + + hyp_spin_unlock(&trace_buffer.lock); + +err_release_desc: + __release_host_mem(desc, desc_size); + return ret; +} + +void __tracing_unload(void) +{ + hyp_spin_lock(&trace_buffer.lock); + hyp_trace_buffer_unload(&trace_buffer); + hyp_spin_unlock(&trace_buffer.lock); +} + +int __tracing_enable(bool enable) +{ + int cpu, ret = enable ? -EINVAL : 0; + + hyp_spin_lock(&trace_buffer.lock); + + if (!hyp_trace_buffer_loaded(&trace_buffer)) + goto unlock; + + for (cpu = 0; cpu < hyp_nr_cpus; cpu++) + simple_ring_buffer_enable_tracing(per_cpu_ptr(trace_buffer.simple_rbs, cpu), + enable); + + ret = 0; + +unlock: + hyp_spin_unlock(&trace_buffer.lock); + + return ret; +} + +int __tracing_swap_reader(unsigned int cpu) +{ + int ret = -ENODEV; + + if (cpu >= hyp_nr_cpus) + return -EINVAL; + + hyp_spin_lock(&trace_buffer.lock); + + if (hyp_trace_buffer_loaded(&trace_buffer)) + ret = simple_ring_buffer_swap_reader_page( + per_cpu_ptr(trace_buffer.simple_rbs, cpu)); + + hyp_spin_unlock(&trace_buffer.lock); + + return ret; +} |