From nobody Thu Apr 2 17:22:44 2026 Received: from mail-wm1-f73.google.com (mail-wm1-f73.google.com [209.85.128.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B93E53FB041 for ; Mon, 9 Mar 2026 16:26:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773073591; cv=none; b=VOd+oBZBZWJbw705BQQNto3687htF1GKJ5jDhoTR1ImQIOVFIuuZd4m4uEg8hjpo3FlBu4xx/9XKKc3qQq6QQMHUVoWvkpI3MUT8wZqJ51+RW/nb4PyBfmC1cwJKaeDsrRwRiJ3vUf1YcTWFFQ0CGaHK/t7AWKi0x52U0kLX9GE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773073591; c=relaxed/simple; bh=uwYQWXJq4cr4nt+LXGOlVB79zrFFf6vy3e6v8doz2/E=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=ng9NQsZxclqwEzk7/a8y3AqpC0k7XzuVsUK2G7gqzvikh3WQ2gDBaA2IfCqLpvIr5qB0OrJVWCaMv6r0KYndSw7iywM0Rm0Ku/b9ftMoBRAn/dikrCmS/HWzs5sVBpZtg/8mxFp0fngxpznKUZtICSFIzXknVIUD5pMUEAy7bgM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=prxdfGvK; arc=none smtp.client-ip=209.85.128.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="prxdfGvK" Received: by mail-wm1-f73.google.com with SMTP id 5b1f17b1804b1-4806cfffca6so129828195e9.2 for ; Mon, 09 Mar 2026 09:26:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1773073587; x=1773678387; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=wZNlRO5e/MGzFMVxx7Ks/cRDmNOcF7u1/X5pARmyFgQ=; b=prxdfGvKC8X/lRfi18HoOMoyMcKREmZ8cuMAlXJd/oSsDwgwvEOhRi7JWn9OZbLzND fSYAmMl+ONRRZ7tt/8RW4yZI6bqyH+j2bk9enEfw/Q3FNwACC+sj/CaSuXHcjAgX7N+X yCI9jTpjiumn6cgRQ/suZNpbxbouw0xt9pHwUoJhH4bRAUKbHD/F38xVEvqU2CAvvca6 hDfHuJipDtDIxxsx+E2vk/ZaCYPnWYYvrA5JIbhaKncZK0x7Jk1Zu6Y3Q3V97rnQtiOY DHTkJFRmZX6T9wNQ/ho5BcQqC2shsYqFu6Q98DhhpXhTPa/PtU941MBObkg2O+4ZDPHg Bpng== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1773073587; x=1773678387; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=wZNlRO5e/MGzFMVxx7Ks/cRDmNOcF7u1/X5pARmyFgQ=; b=VYaBscVKfA12g0d83lgw4J3u3B5MZy5wNdn8KF5JdydEmTPwZdEzUc6XEba9Ueqdbr zXXPC7yQ2GixADcL9pfpq1J2G1UcJFVv4VMhWX5tK0XSFSAyRO5GyQSbl0MIWHS7MT4t 2tw64ej2QZ2U0PKbebW2V465ksiBBVd055jTZ4eJeRujfwWq4hlhwg09MY7FzaWKJr/5 oUlt9BY1LvMj8gxoi2NrgxWoHnESXNMFKVOp9kjoiPbkKeJDNmexq/L385lhuY4ubSjl gAxo0Okoo1O7/kXq7AAoZJMCPGyIf0TJjDj2BlHqWscjwZZ7M6L8S+saj4D50lOLnZG5 l35A== X-Forwarded-Encrypted: i=1; AJvYcCV39SugM76zV/+gJkeFSMU3ztD0Yz0z34pY5HxzzRdBvHEywtaeINoW/idoIr7tPH/T8TPOYnAfVvQ/otc=@vger.kernel.org X-Gm-Message-State: AOJu0Yy0UIk9fM7mJbKUe0rKRyEuaafsID5CVRSQ5/RIbhlsUxAf+eRz LOl55+0/TtIlM5zuzVsWPZvbm0Woe+uQ2Vael7icD3uxtlNXiW4mfh4t1XrL0eLFdWcjehniVw7 NQQ/Q7seLahr2/vAaiSESug== X-Received: from wmet19.prod.google.com ([2002:a05:600c:2ad3:b0:47f:c96e:8381]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:3ba2:b0:485:35ba:1d81 with SMTP id 5b1f17b1804b1-48535ba1ea6mr94547295e9.21.1773073586927; Mon, 09 Mar 2026 09:26:26 -0700 (PDT) Date: Mon, 9 Mar 2026 16:25:12 +0000 In-Reply-To: <20260309162516.2623589-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260309162516.2623589-1-vdonnefort@google.com> X-Mailer: git-send-email 2.53.0.473.g4a7958ca14-goog Message-ID: <20260309162516.2623589-27-vdonnefort@google.com> Subject: [PATCH v14 26/30] KVM: arm64: Add trace reset to the nVHE/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" Make the hypervisor reset either the whole tracing buffer or a specific ring-buffer, on remotes/hypervisor/trace or per_cpu//trace write access. Signed-off-by: Vincent Donnefort diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_= asm.h index 9c4fe3bfbfff..66abf77cf371 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -94,6 +94,7 @@ enum __kvm_host_smccc_func { __KVM_HOST_SMCCC_FUNC___tracing_enable, __KVM_HOST_SMCCC_FUNC___tracing_swap_reader, __KVM_HOST_SMCCC_FUNC___tracing_update_clock, + __KVM_HOST_SMCCC_FUNC___tracing_reset, }; =20 #define DECLARE_KVM_VHE_SYM(sym) extern char sym[] diff --git a/arch/arm64/kvm/hyp/include/nvhe/trace.h b/arch/arm64/kvm/hyp/i= nclude/nvhe/trace.h index fd641e1b1c23..44912869d184 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/trace.h +++ b/arch/arm64/kvm/hyp/include/nvhe/trace.h @@ -12,6 +12,7 @@ void __tracing_unload(void); int __tracing_enable(bool enable); int __tracing_swap_reader(unsigned int cpu); void __tracing_update_clock(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_c= yc); +int __tracing_reset(unsigned int cpu); #else static inline void *tracing_reserve_entry(unsigned long length) { return N= ULL; } static inline void tracing_commit_entry(void) { } @@ -21,5 +22,6 @@ 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= ; } static inline void __tracing_update_clock(u32 mult, u32 shift, u64 epoch_n= s, u64 epoch_cyc) { } +static inline int __tracing_reset(unsigned int cpu) { return -ENODEV; } #endif #endif diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/h= yp-main.c index 02d5271199d5..9b05f0c87586 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -625,6 +625,13 @@ static void handle___tracing_update_clock(struct kvm_c= pu_context *host_ctxt) __tracing_update_clock(mult, shift, epoch_ns, epoch_cyc); } =20 +static void handle___tracing_reset(struct kvm_cpu_context *host_ctxt) +{ + DECLARE_REG(unsigned int, cpu, host_ctxt, 1); + + cpu_reg(host_ctxt, 1) =3D __tracing_reset(cpu); +} + typedef void (*hcall_t)(struct kvm_cpu_context *); =20 #define HANDLE_FUNC(x) [__KVM_HOST_SMCCC_FUNC_##x] =3D (hcall_t)handle_##x @@ -671,6 +678,7 @@ static const hcall_t host_hcall[] =3D { HANDLE_FUNC(__tracing_enable), HANDLE_FUNC(__tracing_swap_reader), HANDLE_FUNC(__tracing_update_clock), + HANDLE_FUNC(__tracing_reset), }; =20 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/trac= e.c index 2c8e6f49d7de..a6ca27b18e15 100644 --- a/arch/arm64/kvm/hyp/nvhe/trace.c +++ b/arch/arm64/kvm/hyp/nvhe/trace.c @@ -287,3 +287,20 @@ void __tracing_update_clock(u32 mult, u32 shift, u64 e= poch_ns, u64 epoch_cyc) /* ...we can now override the old one and swap. */ trace_clock_update(mult, shift, epoch_ns, epoch_cyc); } + +int __tracing_reset(unsigned int cpu) +{ + int ret =3D -ENODEV; + + 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)); + + hyp_spin_unlock(&trace_buffer.lock); + + return ret; +} diff --git a/arch/arm64/kvm/hyp_trace.c b/arch/arm64/kvm/hyp_trace.c index 1e5fc27f0e9d..09bc192e3514 100644 --- a/arch/arm64/kvm/hyp_trace.c +++ b/arch/arm64/kvm/hyp_trace.c @@ -313,7 +313,7 @@ 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(__tracing_reset, cpu); } =20 static int hyp_trace_enable_event(unsigned short id, bool enable, void *pr= iv) --=20 2.53.0.473.g4a7958ca14-goog