From nobody Mon Feb 9 20:30:13 2026 Received: from mail-wr1-f74.google.com (mail-wr1-f74.google.com [209.85.221.74]) (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 07FB33587B0 for ; Sat, 31 Jan 2026 13:29:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769866183; cv=none; b=G4BpJQtFGQWbBXaPrHVnpKlZykid+kVsd9AYbJSOZjeAs5HI9qp9vH1pptW92IRmbISnegiXWD5TrqgQEVz3cMV+BBsU0g0t4bTZmNsN0C9DZnUO/BA2UnxJ6GUMrdEi15+Qn4QjXPqbOPCQk+wrM4IpOAM1m9ZBoJewAvEGXkI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769866183; c=relaxed/simple; bh=Sxuqk4VZ6qANkzLXQvZSMabSZh60GttBUsq4LMXjS1E=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=efHR/ls3J8PSaC+t9uM0LIv1lIfaE69FX1cmCITbdnRVyBmwq+2uX9jBzmDttJzbJMwO6h0l5J3N+IYjjZSjCIzs4n/V3jmohhhhSWU4LUH5q4Uu242tHY8u6+VxPVjJRS0z8PLJOlgErC7OJGZPPLZ9YxDbCLwions33LIIrfE= 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=V2nslo7t; arc=none smtp.client-ip=209.85.221.74 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="V2nslo7t" Received: by mail-wr1-f74.google.com with SMTP id ffacd0b85a97d-4325b182e3cso1998617f8f.2 for ; Sat, 31 Jan 2026 05:29:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1769866177; x=1770470977; 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=g1mZ+ZNkONBjyfcjUN3hF7cGlkHOrtSmM6+OwF5eQuA=; b=V2nslo7t1iXCqDj+kqE0eNseZ7KuhitQtpCr/P9oKvTUqx2/9PIhwbV2CsEzGZEYGp 6Sq3hzTiMhcbWa531IuHNKk/gYjp/MogdFK5bJBxaLfFgC09OI12y+yDeaHF1Owjq7CA V4TzjD4CkVHTZUV4W2AQZ2DV8STi6h5wjUgSRROfaZbTTLFIlJo6JqPReD0Li3lDD/GF saBd0I4cPUP3IvBanGRHKA4guXxqS7LBlJCMAlXZobAM6fM/BKePFAuoqe2z0I6kU+i7 rhujp2n8Bi0oVsvo6l5UHabxwyypvcbETzPrU2qU0Rpm53JZ0wR5fdoOvOiwmQd8kJMO dX3g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769866177; x=1770470977; 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=g1mZ+ZNkONBjyfcjUN3hF7cGlkHOrtSmM6+OwF5eQuA=; b=wFBuCuahkJyOzCPqMpyNMugeV+/lfMy7v9OfOKhyL/57jvgsdf7GAapju4eaUmAZob un/4l0w1C2iy4+KlWpsI1b2uWXeGiHSZl9W6d2ciHQMtrF/IvJ1LzK6xF+hdHPI+CG/R byxNIWgBMeHmZSEatMyHlq2aY8dUDUjiSPv2Z+JCCu92zpSXas3nq+tgNwOABWk9mefu r0DWnGgLsg97F8dO15Ctqith1SNX5ouWZjQeMh9i504ZvHqYIGqXGU1IOcBg96eujbDG Un8O9B6RLu6gOwF04g9CUIeWMV99Tu6ABl+++XpdZawWigiTlxPVC3v891e6m+jJ1YmR 7iig== X-Forwarded-Encrypted: i=1; AJvYcCWBo0R7d7tN1Qf9LaZ6f+kjez2Z8PBXMPjUX1R1tH+vXprv3t7wyHA1GfKFZffDXw99YGHZe738+2PYuog=@vger.kernel.org X-Gm-Message-State: AOJu0YyhhZE5YRGm0Tyzk1YxzwO00aDnTKWqUMCpjqxMumyLRoqaNRAC R0fQDStYtPUMnD2gb6Nl6N8oxizy4Aedvip7KKJW8ptDtecTTCthFqOr8JQ6DeehVYqCHcEZ8fk JEP3FZJfxBpJZpqeB01gVCQ== X-Received: from wrbek14.prod.google.com ([2002:a05:6000:220e:b0:435:f777:d162]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6000:3103:b0:435:dbbe:1130 with SMTP id ffacd0b85a97d-435f3a6ca95mr9449773f8f.11.1769866177281; Sat, 31 Jan 2026 05:29:37 -0800 (PST) Date: Sat, 31 Jan 2026 13:28:35 +0000 In-Reply-To: <20260131132848.254084-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260131132848.254084-1-vdonnefort@google.com> X-Mailer: git-send-email 2.53.0.rc1.225.gd81095ad13-goog Message-ID: <20260131132848.254084-18-vdonnefort@google.com> Subject: [PATCH v11 17/30] tracing: load/unload page callbacks for simple_ring_buffer 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" Add load/unload callback used for each admitted page in the ring-buffer. This will be later useful for the pKVM hypervisor which uses a different VA space and need to dynamically map/unmap the ring-buffer pages. Signed-off-by: Vincent Donnefort diff --git a/include/linux/simple_ring_buffer.h b/include/linux/simple_ring= _buffer.h index 2c4c0ae336bc..21aec556293e 100644 Reviewed-by: Steven Rostedt (Google) --- a/include/linux/simple_ring_buffer.h +++ b/include/linux/simple_ring_buffer.h @@ -54,4 +54,12 @@ int simple_ring_buffer_reset(struct simple_rb_per_cpu *c= pu_buffer); =20 int simple_ring_buffer_swap_reader_page(struct simple_rb_per_cpu *cpu_buff= er); =20 +int simple_ring_buffer_init_mm(struct simple_rb_per_cpu *cpu_buffer, + struct simple_buffer_page *bpages, + const struct ring_buffer_desc *desc, + void *(*load_page)(unsigned long va), + void (*unload_page)(void *va)); + +void simple_ring_buffer_unload_mm(struct simple_rb_per_cpu *cpu_buffer, + void (*unload_page)(void *)); #endif diff --git a/kernel/trace/simple_ring_buffer.c b/kernel/trace/simple_ring_b= uffer.c index 88afd28ffef7..2adfeb5a8f4d 100644 --- a/kernel/trace/simple_ring_buffer.c +++ b/kernel/trace/simple_ring_buffer.c @@ -71,7 +71,7 @@ static void simple_bpage_reset(struct simple_buffer_page = *bpage) local_set(&bpage->page->commit, 0); } =20 -static void simple_bpage_init(struct simple_buffer_page *bpage, unsigned l= ong page) +static void simple_bpage_init(struct simple_buffer_page *bpage, void *page) { INIT_LIST_HEAD(&bpage->link); bpage->page =3D (struct buffer_data_page *)page; @@ -376,19 +376,15 @@ int simple_ring_buffer_reset(struct simple_rb_per_cpu= *cpu_buffer) } EXPORT_SYMBOL_GPL(simple_ring_buffer_reset); =20 -/** - * simple_ring_buffer_init - Init @cpu_buffer based on @desc - * - * @cpu_buffer: A simple_rb_per_cpu buffer to init, allocated by the calle= r. - * @bpages: Array of simple_buffer_pages, with as many elements as @desc->= nr_page_va - * @desc: A ring_buffer_desc - * - * Returns: 0 on success or -EINVAL if the content of @desc is invalid - */ -int simple_ring_buffer_init(struct simple_rb_per_cpu *cpu_buffer, struct s= imple_buffer_page *bpages, - const struct ring_buffer_desc *desc) +int simple_ring_buffer_init_mm(struct simple_rb_per_cpu *cpu_buffer, + struct simple_buffer_page *bpages, + const struct ring_buffer_desc *desc, + void *(*load_page)(unsigned long va), + void (*unload_page)(void *va)) { struct simple_buffer_page *bpage =3D bpages; + int ret =3D 0; + void *page; int i; =20 /* At least 1 reader page and two pages in the ring-buffer */ @@ -397,15 +393,22 @@ int simple_ring_buffer_init(struct simple_rb_per_cpu = *cpu_buffer, struct simple_ =20 memset(cpu_buffer, 0, sizeof(*cpu_buffer)); =20 - cpu_buffer->bpages =3D bpages; + cpu_buffer->meta =3D load_page(desc->meta_va); + if (!cpu_buffer->meta) + return -EINVAL; =20 - cpu_buffer->meta =3D (void *)desc->meta_va; memset(cpu_buffer->meta, 0, sizeof(*cpu_buffer->meta)); cpu_buffer->meta->meta_page_size =3D PAGE_SIZE; cpu_buffer->meta->nr_subbufs =3D cpu_buffer->nr_pages; =20 /* The reader page is not part of the ring initially */ - simple_bpage_init(bpage, desc->page_va[0]); + page =3D load_page(desc->page_va[0]); + if (!page) { + unload_page(cpu_buffer->meta); + return -EINVAL; + } + + simple_bpage_init(bpage, page); bpage->id =3D 0; =20 cpu_buffer->nr_pages =3D 1; @@ -415,7 +418,13 @@ int simple_ring_buffer_init(struct simple_rb_per_cpu *= cpu_buffer, struct simple_ cpu_buffer->head_page =3D bpage + 1; =20 for (i =3D 1; i < desc->nr_page_va; i++) { - simple_bpage_init(++bpage, desc->page_va[i]); + page =3D load_page(desc->page_va[i]); + if (!page) { + ret =3D -EINVAL; + break; + } + + simple_bpage_init(++bpage, page); =20 bpage->link.next =3D &(bpage + 1)->link; bpage->link.prev =3D &(bpage - 1)->link; @@ -424,6 +433,14 @@ int simple_ring_buffer_init(struct simple_rb_per_cpu *= cpu_buffer, struct simple_ cpu_buffer->nr_pages =3D i + 1; } =20 + if (ret) { + for (i--; i >=3D 0; i--) + unload_page((void *)desc->page_va[i]); + unload_page(cpu_buffer->meta); + + return ret; + } + /* Close the ring */ bpage->link.next =3D &cpu_buffer->tail_page->link; cpu_buffer->tail_page->link.prev =3D &bpage->link; @@ -431,25 +448,50 @@ int simple_ring_buffer_init(struct simple_rb_per_cpu = *cpu_buffer, struct simple_ /* The last init'ed page points to the head page */ simple_bpage_set_head_link(bpage); =20 + cpu_buffer->bpages =3D bpages; + return 0; } -EXPORT_SYMBOL_GPL(simple_ring_buffer_init); + +static void *__load_page(unsigned long page) +{ + return (void *)page; +} + +static void __unload_page(void *page) { } =20 /** - * simple_ring_buffer_unload - Prepare @cpu_buffer for deletion + * simple_ring_buffer_init - Init @cpu_buffer based on @desc * - * @cpu_buffer: A simple_rb_per_cpu that will be deleted. + * @cpu_buffer: A simple_rb_per_cpu buffer to init, allocated by the calle= r. + * @bpages: Array of simple_buffer_pages, with as many elements as @desc->= nr_page_va + * @desc: A ring_buffer_desc + * + * Returns: 0 on success or -EINVAL if the content of @desc is invalid */ -void simple_ring_buffer_unload(struct simple_rb_per_cpu *cpu_buffer) +int simple_ring_buffer_init(struct simple_rb_per_cpu *cpu_buffer, struct s= imple_buffer_page *bpages, + const struct ring_buffer_desc *desc) { + return simple_ring_buffer_init_mm(cpu_buffer, bpages, desc, __load_page, = __unload_page); +} +EXPORT_SYMBOL_GPL(simple_ring_buffer_init); + +void simple_ring_buffer_unload_mm(struct simple_rb_per_cpu *cpu_buffer, + void (*unload_page)(void *)) +{ + int p; + if (!simple_rb_loaded(cpu_buffer)) return; =20 simple_rb_enable_tracing(cpu_buffer, false); =20 + unload_page(cpu_buffer->meta); + for (p =3D 0; p < cpu_buffer->nr_pages; p++) + unload_page(cpu_buffer->bpages[p].page); + cpu_buffer->bpages =3D NULL; } -EXPORT_SYMBOL_GPL(simple_ring_buffer_unload); =20 /** * simple_ring_buffer_enable_tracing - Enable or disable writing to @cpu_b= uffer @@ -459,6 +501,12 @@ EXPORT_SYMBOL_GPL(simple_ring_buffer_unload); * * Returns 0 on success or -ENODEV if @cpu_buffer was unloaded */ +void simple_ring_buffer_unload(struct simple_rb_per_cpu *cpu_buffer) +{ + return simple_ring_buffer_unload_mm(cpu_buffer, __unload_page); +} +EXPORT_SYMBOL_GPL(simple_ring_buffer_unload); + int simple_ring_buffer_enable_tracing(struct simple_rb_per_cpu *cpu_buffer= , bool enable) { if (!simple_rb_loaded(cpu_buffer)) --=20 2.53.0.rc1.225.gd81095ad13-goog