From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [RFC 7/11] virtio_pci: new, capability-aware driver.
Date: Tue, 28 May 2013 10:56:13 +0300
Message-ID: <20130528075613.GA23148@redhat.com>
References: <87pqfzgy6p.fsf@rustcorp.com.au> <87zkf3fiu2.fsf@rustcorp.com.au>
	<20111211094256.GB11504@redhat.com>
	<87boreohhs.fsf@rustcorp.com.au> <20111212114912.GA7946@redhat.com>
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To: Rusty Russell <rusty@rustcorp.com.au>
Cc: Sasha Levin <levinsasha928@gmail.com>, virtualization <virtualization@lists.linux-foundation.org>
List-Id: virtualization@lists.linuxfoundation.org

On Mon, Dec 12, 2011 at 01:49:13PM +0200, Michael S. Tsirkin wrote:
> On Mon, Dec 12, 2011 at 09:15:03AM +1030, Rusty Russell wrote:
> > On Sun, 11 Dec 2011 11:42:56 +0200, "Michael S. Tsirkin" <mst@redhat.com> wrote:
> > > On Thu, Dec 08, 2011 at 09:09:33PM +1030, Rusty Russell wrote:
> > > > +/* There is no iowrite64.  We use two 32-bit ops. */
> > > > +static void iowrite64(u64 val, const __le64 *addr)
> > > > +{
> > > > +	iowrite32((u32)val, (__le32 *)addr);
> > > > +	iowrite32(val >> 32, (__le32 *)addr + 1);
> > > > +}
> > > > +
> > > 
> > > Let's put addr_lo/addr_hi in the structure then,
> > > to make the fact this field is not atomic explicit?
> > 
> > Good point, assuming I haven't missed something.
> > 
> > Are 64-bit accesses actually unknown in PCI-land?  Or is this a limited
> > availability thing?
> > 
> > Thanks,
> > Rusty.
> 
> I think PCI can optionally support atomic 64 bit accesses, but not all
> architectures can generate them.

Ping. Going to change this in the layout struct?

> -- 
> MST