From nobody Sat Apr 11 13:57:28 2026 Received: from mail-wm1-f74.google.com (mail-wm1-f74.google.com [209.85.128.74]) (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 879F93A0E95 for ; Fri, 6 Mar 2026 14:36:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772807782; cv=none; b=gVwxx/jH++rQatDWXYuBmbwTUUJc/n/T9pcTV4hNiBJxED0DqbxjLEoA6DnQ1gip1dndlzKG4Sd346C7qCSJVQO+B+XreMOvd+9z0jW8VEAN6Xn23lCZl2+5WCYLUT3rh+42WCayuiKy4RPp5Tf2E7MstCGcijsAmaVYq8ddOrc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772807782; c=relaxed/simple; bh=uwYQWXJq4cr4nt+LXGOlVB79zrFFf6vy3e6v8doz2/E=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=kBfIegHicQ0JkOQweWGhITUEFmN8ErsdwD/MGL3hJjcSuxA5QrJT+2cdRR+bfJ7F6+CX1hrfHWyDF38QcFegvJmPKd1yrfF8kxuWXxJXRdUZGJUUr2XB1ca1whUKupK3Hqgn4MkxoMIPGoh/KUyOKXOKRokQUaLX3I+VE3L5Y64= 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=3jCnQMhh; arc=none smtp.client-ip=209.85.128.74 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="3jCnQMhh" Received: by mail-wm1-f74.google.com with SMTP id 5b1f17b1804b1-483bcfdaf7dso92743405e9.0 for ; Fri, 06 Mar 2026 06:36:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1772807779; x=1773412579; 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=3jCnQMhhpIP8xtEV4vqGqNpyRPA7uHq9lz1XHFzYCu8MUs7pbsJSdT3x1i9dnPGxXw G7dvwx1rFc90p6+14dK/7zs/rwo2xQG6xKnKKKenadlaWoL+ouDgFuFUjVkwpLmMLTH4 +JQbkol/lIu9vBQGvsbS1iqTNuMLNnjdwkNLQpgLFOQFeb0sC+oS17MyWhnTBuGxpv5j ZtDPeIW2md9S0ufXMmhEuOYm++AKDAfQAG8TEf40H2uJh3Wz21qmG0zyg2ON30leE5hq rkdOOqx6yGkAUgEJr5BaMgZGHqrYI6v+De5I8uggfxE4xvHg87pshW3zijgJQLrOc3Zr gokA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772807779; x=1773412579; 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=iEfGwEzzTyffcdcS25AiSR/SC74woGl4XIsvAh6r6hw/LQTG7/kNLygam3SYST1xr+ imLhBw5hsS5grTqcMbmpYuj+NZeNSBCuoqWCl5PTla66ZxF/6e/6RFRMum3Nal2ONphn g7m4v23NY2nCGRWKltyLXkqZxiUOrfvmkxH/eB1Ufc7YRyKPli1NLBEpAWpsb9pQKq1P 21MIbnoZ9vOhmKAoWRzyD5kTR/jxssrxnFj5c1RUmLvuRq35VUxY5UhJ+vrsGC7N6WCe tyzUr86usyoOh7uzOnQxkvtgUeKmm8OMkMWTZgN/+5xYVuUiSp/zD9c/+fzrHctf57W0 y0vw== X-Forwarded-Encrypted: i=1; AJvYcCVlcfh4eNGFL9LYQQyeFSDptYE6BuK4PXAZb6vvWErsaqWXcDbZ27kUdFvgwN2yc1LVVufbc3SfL5vdJGQ=@vger.kernel.org X-Gm-Message-State: AOJu0Yy3YFuYQe+fuJexCVUyR68fvkShs5uFee2SG8QOfMnQ9EpcFnX1 3NDgGb2plEDIc0jM83wKS2dxAQnAoZvjE5EqIj47hxiN493b9SbyvIMCeDP+IPcCDxJwl1ZnUNe Mf6Dlda28OLkCgNl+ZzmzXg== X-Received: from wmbdv11.prod.google.com ([2002:a05:600c:620b:b0:483:7c8d:ed1d]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:5253:b0:483:456a:514b with SMTP id 5b1f17b1804b1-4852692f158mr38056235e9.12.1772807778854; Fri, 06 Mar 2026 06:36:18 -0800 (PST) Date: Fri, 6 Mar 2026 14:35:30 +0000 In-Reply-To: <20260306143536.339777-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260306143536.339777-1-vdonnefort@google.com> X-Mailer: git-send-email 2.53.0.473.g4a7958ca14-goog Message-ID: <20260306143536.339777-27-vdonnefort@google.com> Subject: [PATCH v13 26/32] 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