From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 225816DCE1; Thu, 16 Jan 2025 13:41:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737034912; cv=none; b=iWHCX3Q2Nnce4XwYtL9SM80Yyr81hPZs2YFkQYSBW3js1/JAm9bi7sHWqJ8Jdhs2rhkrrJuhP7E0Dy4SBn4kURRFVUAh71duKOSgcJP1X4OGjR4XEXaQtyBMPMnoc/H/BFAD1pXIyt1KlmJVmq8NSTeNC+p03mPkDA+IoWSr3a0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737034912; c=relaxed/simple; bh=dZSQ4sM6EjdQbV0B/bB4NHAPrinVGMw3NkiqLUx0yQM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=XQxijnslqwdFHDWGh+9Qc+U3XDo1YnPVJza0D8EKJHOmEKwZceseUkaYZPtBJ8ZUysYO1NEfzQKr8qXNY47+xgDm9p8J9nt5WCMLUxU8jVSpCBYVAl2TfNZQDJd6bmW1ivoQSx/h6ofgNkloM0nKsCgmr/OM9WE2e6UNCNroiZU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=jYPn2l7N; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="jYPn2l7N" Received: from hm-sls2.lan (bras-base-toroon4332w-grc-51-184-146-177-43.dsl.bell.ca [184.146.177.43]) by linux.microsoft.com (Postfix) with ESMTPSA id D243B203E393; Thu, 16 Jan 2025 05:41:49 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com D243B203E393 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1737034910; bh=9H7HPLjLJvXQjg3wqMJ0Tj4+R9QjGLbBsj8ckraGB7M=; h=From:To:Cc:Subject:Date:From; b=jYPn2l7Ny7Ng2SU2DcqqFGbZfDmvN2L3bF2UG7bKR4Wa2E7B775z7KwqMkmz0lD0j 8Nf2FUH53KXEMOI7YegrzIrsT/EmE71RcLyu4K+8YTSIWsnE3S0FFjv2sQMfga2oMP IgqVKReVhn3/jL2YDXRDVZUHmkk/ScI0HHCp4AXc= From: Hamza Mahfooz To: linux-hyperv@vger.kernel.org Cc: Hamza Mahfooz , Boqun Feng , Michael Kelley , Wei Liu , "K. Y. Srinivasan" , Haiyang Zhang , Dexuan Cui , linux-kernel@vger.kernel.org Subject: [PATCH v4 1/2] drivers/hv: introduce vmbus_channel_set_cpu() Date: Thu, 16 Jan 2025 08:41:34 -0500 Message-ID: <20250116134136.66749-1-hamzamahfooz@linux.microsoft.com> X-Mailer: git-send-email 2.47.1 Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The core functionality in target_cpu_store() is also needed in a subsequent patch for automatically changing the CPU when taking a CPU offline. As such, factor out the body of target_cpu_store() into new function vmbus_channel_set_cpu() that can also be used elsewhere. No functional change is intended. Cc: Boqun Feng Cc: Michael Kelley Cc: Wei Liu Signed-off-by: Hamza Mahfooz --- v2: separate vmbus_channel_set_cpu() changes from cpu offlining changes. v3: address comments from Michael. --- drivers/hv/vmbus_drv.c | 50 +++++++++++++++++++++++++----------------- include/linux/hyperv.h | 1 + 2 files changed, 31 insertions(+), 20 deletions(-) diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 2892b8da20a5..0ca0e85e6edd 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -1611,16 +1611,16 @@ static ssize_t target_cpu_show(struct vmbus_channel *channel, char *buf) { return sprintf(buf, "%u\n", channel->target_cpu); } -static ssize_t target_cpu_store(struct vmbus_channel *channel, - const char *buf, size_t count) + +int vmbus_channel_set_cpu(struct vmbus_channel *channel, u32 target_cpu) { - u32 target_cpu, origin_cpu; - ssize_t ret = count; + u32 origin_cpu; + int ret = 0; - if (vmbus_proto_version < VERSION_WIN10_V4_1) - return -EIO; + lockdep_assert_cpus_held(); + lockdep_assert_held(&vmbus_connection.channel_mutex); - if (sscanf(buf, "%uu", &target_cpu) != 1) + if (vmbus_proto_version < VERSION_WIN10_V4_1) return -EIO; /* Validate target_cpu for the cpumask_test_cpu() operation below. */ @@ -1630,22 +1630,17 @@ static ssize_t target_cpu_store(struct vmbus_channel *channel, if (!cpumask_test_cpu(target_cpu, housekeeping_cpumask(HK_TYPE_MANAGED_IRQ))) return -EINVAL; - /* No CPUs should come up or down during this. */ - cpus_read_lock(); - - if (!cpu_online(target_cpu)) { - cpus_read_unlock(); + if (!cpu_online(target_cpu)) return -EINVAL; - } /* - * Synchronizes target_cpu_store() and channel closure: + * Synchronizes vmbus_channel_set_cpu() and channel closure: * * { Initially: state = CHANNEL_OPENED } * * CPU1 CPU2 * - * [target_cpu_store()] [vmbus_disconnect_ring()] + * [vmbus_channel_set_cpu()] [vmbus_disconnect_ring()] * * LOCK channel_mutex LOCK channel_mutex * LOAD r1 = state LOAD r2 = state @@ -1660,7 +1655,6 @@ static ssize_t target_cpu_store(struct vmbus_channel *channel, * Note. The host processes the channel messages "sequentially", in * the order in which they are received on a per-partition basis. */ - mutex_lock(&vmbus_connection.channel_mutex); /* * Hyper-V will ignore MODIFYCHANNEL messages for "non-open" channels; @@ -1668,17 +1662,17 @@ static ssize_t target_cpu_store(struct vmbus_channel *channel, */ if (channel->state != CHANNEL_OPENED_STATE) { ret = -EIO; - goto cpu_store_unlock; + goto end; } origin_cpu = channel->target_cpu; if (target_cpu == origin_cpu) - goto cpu_store_unlock; + goto end; if (vmbus_send_modifychannel(channel, hv_cpu_number_to_vp_number(target_cpu))) { ret = -EIO; - goto cpu_store_unlock; + goto end; } /* @@ -1708,9 +1702,25 @@ static ssize_t target_cpu_store(struct vmbus_channel *channel, origin_cpu, target_cpu); } -cpu_store_unlock: +end: + return ret; +} + +static ssize_t target_cpu_store(struct vmbus_channel *channel, + const char *buf, size_t count) +{ + ssize_t ret = count; + u32 target_cpu; + + if (sscanf(buf, "%uu", &target_cpu) != 1) + return -EIO; + + cpus_read_lock(); + mutex_lock(&vmbus_connection.channel_mutex); + ret = vmbus_channel_set_cpu(channel, target_cpu); mutex_unlock(&vmbus_connection.channel_mutex); cpus_read_unlock(); + return ret; } static VMBUS_CHAN_ATTR(cpu, 0644, target_cpu_show, target_cpu_store); diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index 02a226bcf0ed..25e9e982f1b0 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -1670,6 +1670,7 @@ int vmbus_send_tl_connect_request(const guid_t *shv_guest_servie_id, const guid_t *shv_host_servie_id); int vmbus_send_modifychannel(struct vmbus_channel *channel, u32 target_vp); void vmbus_set_event(struct vmbus_channel *channel); +int vmbus_channel_set_cpu(struct vmbus_channel *channel, u32 target_cpu); /* Get the start of the ring buffer. */ static inline void * -- 2.47.1