Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
KVM: arm64: Add event support to the nVHE/pKVM hyp and trace remote
Allow the creation of hypervisor and trace remote events with a single
macro HYP_EVENT(). That macro expands in the kernel side to add all
the required declarations (based on REMOTE_EVENT()) as well as in the
hypervisor side to create the trace_<event>() function.
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Link: https://patch.msgid.link/20260309162516.2623589-28-vdonnefort@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
authored by
Vincent Donnefort
and committed by
Marc Zyngier
0a90fbc8
2194d317
+184
-2
+1
arch/arm64/include/asm/kvm_asm.h
+1
arch/arm64/include/asm/kvm_asm.h
+16
arch/arm64/include/asm/kvm_define_hypevents.h
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arch/arm64/include/asm/kvm_define_hypevents.h
···
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/* SPDX-License-Identifier: GPL-2.0 */
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#define REMOTE_EVENT_INCLUDE_FILE arch/arm64/include/asm/kvm_hypevents.h
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#define REMOTE_EVENT_SECTION "_hyp_events"
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#define HE_STRUCT(__args) __args
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#define HE_PRINTK(__args...) __args
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#define he_field re_field
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#define HYP_EVENT(__name, __proto, __struct, __assign, __printk) \
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REMOTE_EVENT(__name, 0, RE_STRUCT(__struct), RE_PRINTK(__printk))
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#define HYP_EVENT_MULTI_READ
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#include <trace/define_remote_events.h>
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#undef HYP_EVENT_MULTI_READ
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arch/arm64/include/asm/kvm_hypevents.h
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arch/arm64/include/asm/kvm_hypevents.h
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arch/arm64/include/asm/kvm_hyptrace.h
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arch/arm64/include/asm/kvm_hyptrace.h
···
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struct trace_buffer_desc trace_buffer_desc;
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};
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struct hyp_event_id {
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unsigned short id;
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atomic_t enabled;
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};
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extern struct remote_event __hyp_events_start[];
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extern struct remote_event __hyp_events_end[];
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/* hyp_event section used by the hypervisor */
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extern struct hyp_event_id __hyp_event_ids_start[];
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extern struct hyp_event_id __hyp_event_ids_end[];
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#endif
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arch/arm64/kernel/image-vars.h
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arch/arm64/kernel/image-vars.h
···
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KVM_NVHE_ALIAS(__hyp_data_end);
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KVM_NVHE_ALIAS(__hyp_rodata_start);
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KVM_NVHE_ALIAS(__hyp_rodata_end);
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#ifdef CONFIG_NVHE_EL2_TRACING
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KVM_NVHE_ALIAS(__hyp_event_ids_start);
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KVM_NVHE_ALIAS(__hyp_event_ids_end);
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#endif
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/* pKVM static key */
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KVM_NVHE_ALIAS(kvm_protected_mode_initialized);
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arch/arm64/kernel/vmlinux.lds.S
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arch/arm64/kernel/vmlinux.lds.S
···
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*(__kvm_ex_table) \
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__stop___kvm_ex_table = .;
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#ifdef CONFIG_NVHE_EL2_TRACING
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#define HYPERVISOR_EVENT_IDS \
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. = ALIGN(PAGE_SIZE); \
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__hyp_event_ids_start = .; \
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*(HYP_SECTION_NAME(.event_ids)) \
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__hyp_event_ids_end = .;
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#else
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#define HYPERVISOR_EVENT_IDS
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#endif
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#define HYPERVISOR_RODATA_SECTIONS \
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HYP_SECTION_NAME(.rodata) : { \
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. = ALIGN(PAGE_SIZE); \
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__hyp_rodata_start = .; \
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*(HYP_SECTION_NAME(.data..ro_after_init)) \
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*(HYP_SECTION_NAME(.rodata)) \
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HYPERVISOR_EVENT_IDS \
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. = ALIGN(PAGE_SIZE); \
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__hyp_rodata_end = .; \
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}
···
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HYPERVISOR_DATA_SECTION
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#ifdef CONFIG_NVHE_EL2_TRACING
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.data.hyp_events : {
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__hyp_events_start = .;
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*(SORT(_hyp_events.*))
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__hyp_events_end = .;
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}
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#endif
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/*
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* Data written with the MMU off but read with the MMU on requires
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* cache lines to be invalidated, discarding up to a Cache Writeback
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arch/arm64/kvm/hyp/include/nvhe/define_events.h
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arch/arm64/kvm/hyp/include/nvhe/define_events.h
···
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/* SPDX-License-Identifier: GPL-2.0 */
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#undef HYP_EVENT
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#define HYP_EVENT(__name, __proto, __struct, __assign, __printk) \
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struct hyp_event_id hyp_event_id_##__name \
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__section(".hyp.event_ids."#__name) = { \
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.enabled = ATOMIC_INIT(0), \
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}
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#define HYP_EVENT_MULTI_READ
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#include <asm/kvm_hypevents.h>
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#undef HYP_EVENT_MULTI_READ
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#undef HYP_EVENT
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arch/arm64/kvm/hyp/include/nvhe/trace.h
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arch/arm64/kvm/hyp/include/nvhe/trace.h
···
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/* SPDX-License-Identifier: GPL-2.0-only */
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#ifndef __ARM64_KVM_HYP_NVHE_TRACE_H
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#define __ARM64_KVM_HYP_NVHE_TRACE_H
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#include <linux/trace_remote_event.h>
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#include <asm/kvm_hyptrace.h>
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#define HE_PROTO(__args...) __args
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#define HE_ASSIGN(__args...) __args
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#define HE_STRUCT RE_STRUCT
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#define he_field re_field
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#ifdef CONFIG_NVHE_EL2_TRACING
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#define HYP_EVENT(__name, __proto, __struct, __assign, __printk) \
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REMOTE_EVENT_FORMAT(__name, __struct); \
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extern struct hyp_event_id hyp_event_id_##__name; \
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static __always_inline void trace_##__name(__proto) \
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{ \
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struct remote_event_format_##__name *__entry; \
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size_t length = sizeof(*__entry); \
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\
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if (!atomic_read(&hyp_event_id_##__name.enabled)) \
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return; \
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__entry = tracing_reserve_entry(length); \
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if (!__entry) \
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return; \
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__entry->hdr.id = hyp_event_id_##__name.id; \
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__assign \
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tracing_commit_entry(); \
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}
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void *tracing_reserve_entry(unsigned long length);
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void tracing_commit_entry(void);
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···
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int __tracing_swap_reader(unsigned int cpu);
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void __tracing_update_clock(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc);
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int __tracing_reset(unsigned int cpu);
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int __tracing_enable_event(unsigned short id, bool enable);
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#else
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static inline void *tracing_reserve_entry(unsigned long length) { return NULL; }
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static inline void tracing_commit_entry(void) { }
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#define HYP_EVENT(__name, __proto, __struct, __assign, __printk) \
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static inline void trace_##__name(__proto) {}
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static inline int __tracing_load(unsigned long desc_va, size_t desc_size) { return -ENODEV; }
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static inline void __tracing_unload(void) { }
···
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static inline int __tracing_swap_reader(unsigned int cpu) { return -ENODEV; }
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static inline void __tracing_update_clock(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc) { }
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static inline int __tracing_reset(unsigned int cpu) { return -ENODEV; }
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static inline int __tracing_enable_event(unsigned short id, bool enable) { return -ENODEV; }
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#endif
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#endif
+1
-1
arch/arm64/kvm/hyp/nvhe/Makefile
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-1
arch/arm64/kvm/hyp/nvhe/Makefile
···
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../fpsimd.o ../hyp-entry.o ../exception.o ../pgtable.o
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hyp-obj-y += ../../../kernel/smccc-call.o
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hyp-obj-$(CONFIG_LIST_HARDENED) += list_debug.o
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hyp-obj-$(CONFIG_NVHE_EL2_TRACING) += clock.o trace.o
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hyp-obj-$(CONFIG_NVHE_EL2_TRACING) += clock.o trace.o events.o
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hyp-obj-y += $(lib-objs)
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# Path to simple_ring_buffer.c
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arch/arm64/kvm/hyp/nvhe/events.c
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arch/arm64/kvm/hyp/nvhe/events.c
···
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2025 Google LLC
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* Author: Vincent Donnefort <vdonnefort@google.com>
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*/
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#include <nvhe/mm.h>
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#include <nvhe/trace.h>
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#include <nvhe/define_events.h>
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int __tracing_enable_event(unsigned short id, bool enable)
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{
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struct hyp_event_id *event_id = &__hyp_event_ids_start[id];
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atomic_t *enabled;
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if (event_id >= __hyp_event_ids_end)
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return -EINVAL;
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enabled = hyp_fixmap_map(__hyp_pa(&event_id->enabled));
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atomic_set(enabled, enable);
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hyp_fixmap_unmap();
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return 0;
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}
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arch/arm64/kvm/hyp/nvhe/hyp-main.c
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arch/arm64/kvm/hyp/nvhe/hyp-main.c
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cpu_reg(host_ctxt, 1) = __tracing_reset(cpu);
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}
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static void handle___tracing_enable_event(struct kvm_cpu_context *host_ctxt)
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{
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DECLARE_REG(unsigned short, id, host_ctxt, 1);
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DECLARE_REG(bool, enable, host_ctxt, 2);
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cpu_reg(host_ctxt, 1) = __tracing_enable_event(id, enable);
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}
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typedef void (*hcall_t)(struct kvm_cpu_context *);
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#define HANDLE_FUNC(x) [__KVM_HOST_SMCCC_FUNC_##x] = (hcall_t)handle_##x
···
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HANDLE_FUNC(__tracing_swap_reader),
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HANDLE_FUNC(__tracing_update_clock),
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HANDLE_FUNC(__tracing_reset),
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HANDLE_FUNC(__tracing_enable_event),
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};
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static void handle_host_hcall(struct kvm_cpu_context *host_ctxt)
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arch/arm64/kvm/hyp/nvhe/hyp.lds.S
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arch/arm64/kvm/hyp/nvhe/hyp.lds.S
···
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HYP_SECTION(.text)
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HYP_SECTION(.data..ro_after_init)
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HYP_SECTION(.rodata)
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#ifdef CONFIG_NVHE_EL2_TRACING
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. = ALIGN(PAGE_SIZE);
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BEGIN_HYP_SECTION(.event_ids)
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*(SORT(.hyp.event_ids.*))
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END_HYP_SECTION
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#endif
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/*
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* .hyp..data..percpu needs to be page aligned to maintain the same
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arch/arm64/kvm/hyp_trace.c
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arch/arm64/kvm/hyp_trace.c
···
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static int hyp_trace_enable_event(unsigned short id, bool enable, void *priv)
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{
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struct hyp_event_id *event_id = lm_alias(&__hyp_event_ids_start[id]);
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struct page *page;
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atomic_t *enabled;
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void *map;
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if (is_protected_kvm_enabled())
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return kvm_call_hyp_nvhe(__tracing_enable_event, id, enable);
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enabled = &event_id->enabled;
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page = virt_to_page(enabled);
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map = vmap(&page, 1, VM_MAP, PAGE_KERNEL);
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if (!map)
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return -ENOMEM;
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enabled = map + offset_in_page(enabled);
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atomic_set(enabled, enable);
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vunmap(map);
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return 0;
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}
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···
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.enable_event = hyp_trace_enable_event,
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};
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#include <asm/kvm_define_hypevents.h>
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static void __init hyp_trace_init_events(void)
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{
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struct hyp_event_id *hyp_event_id = __hyp_event_ids_start;
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struct remote_event *event = __hyp_events_start;
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int id = 0;
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/* Events on both sides hypervisor are sorted */
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for (; event < __hyp_events_end; event++, hyp_event_id++, id++)
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event->id = hyp_event_id->id = id;
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}
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int __init kvm_hyp_trace_init(void)
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{
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int cpu;
···
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}
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#endif
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return trace_remote_register("hypervisor", &trace_remote_callbacks, &trace_buffer, NULL, 0);
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hyp_trace_init_events();
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return trace_remote_register("hypervisor", &trace_remote_callbacks, &trace_buffer,
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__hyp_events_start, __hyp_events_end - __hyp_events_start);
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}