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Subject: Re: [PATCH RFC 00/15] Add VFIO mediated device support and IMS
 support for the idxd driver.
To:     Jason Gunthorpe <jgg@mellanox.com>,
        Dan Williams <dan.j.williams@intel.com>
Cc:     Dave Jiang <dave.jiang@intel.com>, Vinod Koul <vkoul@kernel.org>,
        maz@kernel.org, Bjorn Helgaas <bhelgaas@google.com>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Greg KH <gregkh@linuxfoundation.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Alex Williamson <alex.williamson@redhat.com>,
        Jacob jun Pan <jacob.jun.pan@intel.com>,
        "Raj, Ashok" <ashok.raj@intel.com>, Yi L Liu <yi.l.liu@intel.com>,
        Baolu Lu <baolu.lu@intel.com>,
        "Tian, Kevin" <kevin.tian@intel.com>,
        Sanjay K Kumar <sanjay.k.kumar@intel.com>,
        "Luck, Tony" <tony.luck@intel.com>, Jing Lin <jing.lin@intel.com>,
        kwankhede@nvidia.com, eric.auger@redhat.com, parav@mellanox.com,
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From:   "Dey, Megha" <megha.dey@linux.intel.com>
Message-ID: <c50c2eda-88aa-00bc-7cd6-37cc26052cd5@linux.intel.com>
Date:   Fri, 1 May 2020 15:31:14 -0700
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Hi Jason,

On 4/23/2020 12:49 PM, Jason Gunthorpe wrote:
> On Thu, Apr 23, 2020 at 12:17:50PM -0700, Dan Williams wrote:
> 
>> Per Megha's follow-up can you send the details about that other device
>> and help clear a path for a device-specific MSI addr/data table
>> format. Ever since HMM I've been sensitive, perhaps overly-sensitive,
>> to claims about future upstream users. The fact that you have an
>> additional use case is golden for pushing this into a common area and
>> validating the scope of the proposed API.
> 
> I think I said it at plumbers, but yes, we are interested in this, and
> would like dynamic MSI-like interrupts available to the driver (what
> Intel calls IMS)
> 

So basically you are looking for a way to dynamically allocate the 
platform-msi interrupts, correct?

Since I don't have access to any of the platform-msi devices, it is hard 
for me to test this code for other drivers expect idxd for now.
Once I submit the next round of patches, after addressing all the 
comments, would it be possible for you to test this code for any of your 
devices?

> It is something easy enough to illustrate with any RDMA device really,
> just open a MR against the addr and use RDMA_WRITE to trigger the
> data. It should trigger a Linux IRQ. Nothing else should be needed.
> 
> Jason
>