From: Jason Gunthorpe <jgg@ziepe.ca>
To: Keith Busch <kbusch@kernel.org>
Cc: Alex Williamson <alex.williamson@redhat.com>,
Keith Busch <kbusch@meta.com>,
kvm@vger.kernel.org
Subject: Re: [PATCH rfc] vfio-pci: Allow write combining
Date: Fri, 2 Aug 2024 11:33:15 -0300 [thread overview]
Message-ID: <20240802143315.GB676757@ziepe.ca> (raw)
In-Reply-To: <ZqzsMcrEg5MCV48t@kbusch-mbp.dhcp.thefacebook.com>
On Fri, Aug 02, 2024 at 08:24:49AM -0600, Keith Busch wrote:
> On Thu, Aug 01, 2024 at 11:33:44AM -0600, Alex Williamson wrote:
> > On Thu, 1 Aug 2024 14:13:55 -0300
> > Jason Gunthorpe <jgg@ziepe.ca> wrote:
> >
> > > On Thu, Aug 01, 2024 at 10:52:18AM -0600, Alex Williamson wrote:
> >
> > > > We'd populate these new regions only for BARs that support prefetch and
> > > > mmap
> > >
> > > That's not the point, prefetch has nothing to do with write combining.
> >
> > I was following the original proposal in this thread that added a
> > prefetch flag to REGION_INFO and allowed enabling WC only for
> > IORESOURCE_PREFETCH.
>
> Which itself follows the existing pattern from
> pci_create_resource_files(), which creates a write combine
> resource<X>_wc file only when IORESOURCE_PREFETCH is set. But yeah,
> prefetch isn't necessary for wc, but it seems to indicate it's safe.
Yes, I know, that code isn't right either... It seems to be the root
of this odd "prefetch and WC are related" idea.
Jason
next prev parent reply other threads:[~2024-08-02 14:33 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-31 15:53 [PATCH rfc] vfio-pci: Allow write combining Keith Busch
2024-08-01 14:19 ` Jason Gunthorpe
2024-08-01 15:41 ` Alex Williamson
2024-08-01 16:11 ` Jason Gunthorpe
2024-08-01 16:52 ` Alex Williamson
2024-08-01 17:13 ` Jason Gunthorpe
2024-08-01 17:33 ` Alex Williamson
2024-08-01 17:53 ` Jason Gunthorpe
2024-08-01 18:16 ` Alex Williamson
2024-08-02 11:53 ` Jason Gunthorpe
2024-08-02 17:05 ` Alex Williamson
2024-08-06 16:53 ` Jason Gunthorpe
2024-08-06 18:43 ` Alex Williamson
2024-08-07 14:19 ` Jason Gunthorpe
2024-08-07 17:46 ` Alex Williamson
2024-08-13 18:02 ` Jason Gunthorpe
2024-08-02 14:24 ` Keith Busch
2024-08-02 14:33 ` Jason Gunthorpe [this message]
2024-08-06 7:19 ` Tian, Kevin
2024-08-06 16:47 ` Jason Gunthorpe
2024-08-15 5:05 ` Christoph Hellwig
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