linux-kernel - Re: [PATCH 1/2] cxl/pci: Add generic MSI-X/MSI irq support

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20221102225406.GA5803@bhelgaas>
Date:   Wed, 2 Nov 2022 17:54:06 -0500
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     Davidlohr Bueso <dave@...olabs.net>
Cc:     Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Ira Weiny <ira.weiny@...el.com>, dave.jiang@...el.com,
        alison.schofield@...el.com, bwidawsk@...nel.org,
        vishal.l.verma@...el.com, a.manzanares@...sung.com,
        linux-cxl@...r.kernel.org, linux-kernel@...r.kernel.org,
        Bjorn Helgaas <bhelgaas@...gle.com>, linux-pci@...r.kernel.org,
        Christoph Hellwig <hch@....de>
Subject: Re: [PATCH 1/2] cxl/pci: Add generic MSI-X/MSI irq support

On Wed, Nov 02, 2022 at 10:15:24AM -0700, Davidlohr Bueso wrote:
> On Tue, 25 Oct 2022, Bjorn Helgaas wrote:
> ...

> > The MSI case is ugly because the Interrupt Message Number can change
> > when we set Multiple Message Enable.  Maybe we can separate it out and
> > have a less than optimal solution for this case, like allocating one
> > or two vectors and polling if that's not enough.  I expect most
> > devices will support MSI-X.
> 
> Would only supporting MSI-X be so terrible?

My gut feeling is that polling when MSI-X isn't supported wouldn't be
terrible, but I have no data on how common devices that only support
MSI are.

Bjorn