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Date: Sun, 18 Feb 2024 08:10:36 +0100
From: Greg KH <gregkh@linuxfoundation.org>
To: Saurabh Sengar <ssengar@linux.microsoft.com>
Cc: kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org,
	decui@microsoft.com, linux-hyperv@vger.kernel.org,
	linux-kernel@vger.kernel.org, ssengar@microsoft.com
Subject: Re: [PATCH 0/6] Low speed Hyper-V devices support
Message-ID: <2024021812-shrouded-fanciness-06ec@gregkh>
References: <1708193020-14740-1-git-send-email-ssengar@linux.microsoft.com>
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In-Reply-To: <1708193020-14740-1-git-send-email-ssengar@linux.microsoft.com>

On Sat, Feb 17, 2024 at 10:03:34AM -0800, Saurabh Sengar wrote:
> Hyper-V is adding multiple low speed "speciality" synthetic devices.
> Instead of writing a new kernel-level VMBus driver for each device,
> make the devices accessible to user space through UIO-based
> uio_hv_generic driver. Each device can then be supported by a user
> space driver. This approach optimizes the development process and
> provides flexibility to user space applications to control the key
> interactions with the VMBus ring buffer.
> 
> The new synthetic devices are low speed devices that don't support
> VMBus monitor bits, and so they must use vmbus_setevent() to notify
> the host of ring buffer updates. These new devices also have smaller
> ring buffer sizes which requires to add support for variable ring buffer
> sizes.
> 
> Moreover, this patch series adds a new implementation of the fcopy
> application that uses the new UIO driver. The older fcopy driver and
> application will be phased out gradually. Development of other similar
> userspace drivers is still underway.
> 
> 
> Efforts have been made previously to implement this solution earlier.
> Here are the discussions related to those attempts:
> https://lore.kernel.org/lkml/1691132996-11706-1-git-send-email-ssengar@linux.microsoft.com/
> https://lore.kernel.org/lkml/1665575806-27990-1-git-send-email-ssengar@linux.microsoft.com/
> https://lore.kernel.org/lkml/1665685754-13971-1-git-send-email-ssengar@linux.microsoft.com/

So is this a v4 of the patch series?  What has changed from those
previous submissions?

thanks,

greg k-h