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 26BD718B484; Thu, 14 Nov 2024 17:47:12 +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=1731606433; cv=none; b=sz75DTtiVhvm3sn1g4OI7s6PaPKYmjJJREV2K033ZChTe7CgzSsVMMBJch4NpQ4QpsCJPktJcq+nTnA9F1w7gAvYFART62ZaG3Z25Ge8QUmCJWcf22x/dOd6cE+vImEdigB0BzKivIZGKjWTPHEO0Z9n8/qt+yqJY2oXV9okdb0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731606433; c=relaxed/simple; bh=ID8ZhFiwzsT6f68DK1Sq/ms9TWIt+cLdct40zfYVDhQ=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=SurJl+5OPWa2duATDV9ZiEal0b2njTN5sFEMC1RjKlCT1Baq00U7rstCEGNhYT2Oq+e1MX377ONgBDvc7r1bAvj1/25A9NaXHXeGgiriLrud8Vny6ZeXIqpXBhT3d8L2iuL4u/6IWbyGHc7uDJGA0jdtSQQ6lvL3PTM65nRYhPQ= 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=dGEpXD8C; 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="dGEpXD8C" Received: from [192.168.35.166] (c-73-118-245-227.hsd1.wa.comcast.net [73.118.245.227]) by linux.microsoft.com (Postfix) with ESMTPSA id 0F7F120BEBFD; Thu, 14 Nov 2024 09:47:10 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 0F7F120BEBFD DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1731606430; bh=tv6R0dfqeJn4Gt9XYkh+9bVP07MCUYjrl1v5JAVZfsE=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=dGEpXD8C934fobk6knh2OeWKyFUtuXwN5EKsxyMqluoYdmPY9/v5yrBk/nEPeUZXJ mqNMtESikRdQQmFjTcKnLmgXRZSiy7loawioMT2eUFmTqkzmZRPnDiADBSeTyW8vzq HToL/wLvV1rq2amU+q4Dnp0m2iIMJo9C2bLiLMt0= Message-ID: <34a3e85d-4dbd-4550-a74b-5807d71a007e@linux.microsoft.com> Date: Thu, 14 Nov 2024 09:47:09 -0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: eahariha@linux.microsoft.com, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, John Starks , jacob.pan@linux.microsoft.com, Michael Kelley , Saurabh Singh Sengar Subject: Re: [PATCH v3 0/2] Drivers: hv: vmbus: Wait for boot-time offers and log missing offers To: Naman Jain , "K . Y . Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui References: <20241113084700.2940-1-namjain@linux.microsoft.com> Content-Language: en-US From: Easwar Hariharan In-Reply-To: <20241113084700.2940-1-namjain@linux.microsoft.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 11/13/2024 12:46 AM, Naman Jain wrote: > After VM requests for channel offers during boot or resume from > hibernation, host offers the devices that the VM is configured with and > then sends a separate message indicating that all the boot-time channel > offers are delivered. Wait for this message to make this boot-time offers > request and receipt process synchronous. > > Without this, user mode can race with VMBus initialization and miss > channel offers. User mode has no way to work around this other than > sleeping for a while, since there is no way to know when VMBus has > finished processing boot-time offers. > > This is in analogy to a PCI bus not returning from probe until it has > scanned all devices on the bus. > > As part of this implementation, some code cleanup is also done for the > logic which becomes redundant due to this change. > > Second patch prints the channels which are not offered when resume > happens from hibernation to supply more information to the end user. > > Changes since v2: > https://lore.kernel.org/all/20241029080147.52749-1-namjain@linux.microsoft.com/ > * Incorporated Easwar's suggestion to use secs_to_jiffies() as his > changes are now merged. > * Addressed Michael's comments: > * Used boot-time offers/channels/devices to maintain consistency > * Rephrased CHANNELMSG_ALLOFFERS_DELIVERED handler function comments > for better explanation. Thanks for sharing the write-up. > * Changed commit msg and other things as per suggestions > * Addressed Dexuan's comments, which came up in offline discussion: > * Changed timeout for waiting for all offers delivered msg to 60s instead of 10s. > Reason being, the host can experience some servicing events or diagnostics events, > which may take a long time and hence may fail to offer all the devices within 10s. > * Minor additions in commit subject of both patches > * Rebased on latest linux-next master tip > > Changes since v1: > https://lore.kernel.org/all/20241018115811.5530-1-namjain@linux.microsoft.com/ > * Added Easwar's Reviewed-By tag > * Addressed Michael's comments: > * Added explanation of all offers delivered message in comments > * Removed infinite wait for offers logic, and changed it wait once. > * Removed sub channel workqueue flush logic > * Added comments on why MLX device offer is not expected as part of > this essential boot offer list. I refrained from adding too many > details on it as it felt like it is beyond the scope of this patch > series and may not be relevant to this. However, please let me know if > something needs to be added. > * Addressed Saurabh's comments: > * Changed timeout value to 10000 ms instead of 10*1000 > * Changed commit msg as per suggestions > * Added a comment for warning case of wait_for_completion timeout > * Added a note for missing channel cleanup in comments and commit msg > > John Starks (1): > Drivers: hv: vmbus: Log on missing offers if any > > Naman Jain (1): > Drivers: hv: vmbus: Wait for boot-time offers during boot and resume > > drivers/hv/channel_mgmt.c | 61 +++++++++++++++++++++++++++++---------- > drivers/hv/connection.c | 4 +-- > drivers/hv/hyperv_vmbus.h | 14 ++------- > drivers/hv/vmbus_drv.c | 31 ++++++++++---------- > 4 files changed, 67 insertions(+), 43 deletions(-) > > > base-commit: 28955f4fa2823e39f1ecfb3a37a364563527afbc For the series: Reviewed-by: Easwar Hariharan