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AJvYcCWb8gUSa1IQ1Im5h1Cg7nVeRR1/jExjJMqmQkdNlVQjvGD8ZIStHIvvXPVtJE0d5tyH77h/t0/Ky1RBlD0=@vger.kernel.org X-Gm-Message-State: AOJu0YyUCtMAO8s403fWkjvCoosBQCpaq8Q0oBqAOcci5YvN1HWnntde 96AbQGpDdAhGuGjmjJimLWoHg58TQ5M9/lrC0t6k1Wr2Wdfm8mrnO7k3T3dtTKawhN81/S5R2Ba dlvKF8L/TpkzdXMUP/ArMfA== X-Google-Smtp-Source: AGHT+IHkRp/N9BfpTVKwGlWfyc4Y1rtqqdCtN6rhng36wKjtc+HvLOewKvEx2dD8PFbJvsAmqePp4tbQ3CaaD1np X-Received: from wrui2.prod.google.com ([2002:a5d:6302:0:b0:429:de3f:8287]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6000:1869:b0:429:c93b:7f6b with SMTP id ffacd0b85a97d-42ae5ae8b68mr2108050f8f.53.1762508350492; Fri, 07 Nov 2025 01:39:10 -0800 (PST) Date: Fri, 7 Nov 2025 09:38:36 +0000 In-Reply-To: <20251107093840.3779150-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20251107093840.3779150-1-vdonnefort@google.com> X-Mailer: git-send-email 2.51.2.1041.gc1ab5b90ca-goog Message-ID: <20251107093840.3779150-25-vdonnefort@google.com> Subject: [PATCH v8 24/28] KVM: arm64: Add trace reset to the pKVM hyp 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, aneesh.kumar@kernel.org, kernel-team@android.com, linux-kernel@vger.kernel.org, Vincent Donnefort Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Let the hypervisor reset the trace buffer when triggered from the tracefs file remotes/hypervisor/trace. Signed-off-by: Vincent Donnefort diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_= asm.h index b6e016584de7..4faabf398881 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -93,6 +93,7 @@ enum __kvm_host_smccc_func { __KVM_HOST_SMCCC_FUNC___pkvm_load_tracing, __KVM_HOST_SMCCC_FUNC___pkvm_unload_tracing, __KVM_HOST_SMCCC_FUNC___pkvm_enable_tracing, + __KVM_HOST_SMCCC_FUNC___pkvm_reset_tracing, __KVM_HOST_SMCCC_FUNC___pkvm_swap_reader_tracing, }; =20 diff --git a/arch/arm64/kvm/hyp/include/nvhe/trace.h b/arch/arm64/kvm/hyp/i= nclude/nvhe/trace.h index 4e11dcdf049b..0d2732f0d406 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/trace.h +++ b/arch/arm64/kvm/hyp/include/nvhe/trace.h @@ -11,6 +11,7 @@ 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_unload_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 N= ULL; } @@ -21,6 +22,7 @@ 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_s= ize) { return -ENODEV; } static inline void __pkvm_unload_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 -E= NODEV; } #endif #endif diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/h= yp-main.c index d13ab9baceb6..8adad701fc76 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -620,6 +620,13 @@ static void handle___pkvm_enable_tracing(struct kvm_cp= u_context *host_ctxt) cpu_reg(host_ctxt, 1) =3D __pkvm_enable_tracing(enable); } =20 +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) =3D __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); @@ -672,6 +679,7 @@ static const hcall_t host_hcall[] =3D { HANDLE_FUNC(__pkvm_load_tracing), HANDLE_FUNC(__pkvm_unload_tracing), HANDLE_FUNC(__pkvm_enable_tracing), + HANDLE_FUNC(__pkvm_reset_tracing), HANDLE_FUNC(__pkvm_swap_reader_tracing), }; =20 diff --git a/arch/arm64/kvm/hyp/nvhe/trace.c b/arch/arm64/kvm/hyp/nvhe/trac= e.c index d146ac3046de..1fd9b32950fe 100644 --- a/arch/arm64/kvm/hyp/nvhe/trace.c +++ b/arch/arm64/kvm/hyp/nvhe/trace.c @@ -236,6 +236,25 @@ int __pkvm_enable_tracing(bool enable) return ret; } =20 +int __pkvm_reset_tracing(unsigned int cpu) +{ + int ret =3D 0; + + if (cpu >=3D hyp_nr_cpus) + return -EINVAL; + + hyp_spin_lock(&trace_buffer.lock); + + if (hyp_trace_buffer_loaded(&trace_buffer)) + ret =3D simple_ring_buffer_reset(per_cpu_ptr(trace_buffer.simple_rbs, cp= u)); + else + ret =3D -ENODEV; + + hyp_spin_unlock(&trace_buffer.lock); + + return ret; +} + int __pkvm_swap_reader_tracing(unsigned int cpu) { int ret; diff --git a/arch/arm64/kvm/hyp_trace.c b/arch/arm64/kvm/hyp_trace.c index 4f154ec743f3..1062b4310f8c 100644 --- a/arch/arm64/kvm/hyp_trace.c +++ b/arch/arm64/kvm/hyp_trace.c @@ -302,7 +302,7 @@ static int hyp_trace_swap_reader_page(unsigned int cpu,= void *priv) =20 static int hyp_trace_reset(unsigned int cpu, void *priv) { - return 0; + return kvm_call_hyp_nvhe(__pkvm_reset_tracing, cpu); } =20 static int hyp_trace_enable_event(unsigned short id, bool enable, void *pr= iv) --=20 2.51.2.1041.gc1ab5b90ca-goog