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From: "Michael S. Tsirkin" <mst@redhat.com>
To: Avi Kivity <avi@redhat.com>
Cc: Alexey Korolev <alexey.korolev@endace.com>,
	sfd@endace.com, Alex Williamson <alex.williamson@redhat.com>,
	Kevin O'Connor <kevin@koconnor.net>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [RFC/PATCH] Fix guest OS panic when 64bit BAR is present
Date: Thu, 26 Jan 2012 16:05:43 +0200	[thread overview]
Message-ID: <20120126140543.GC17198@redhat.com> (raw)
In-Reply-To: <4F215A4A.1000400@redhat.com>

On Thu, Jan 26, 2012 at 03:51:06PM +0200, Avi Kivity wrote:
> > Please look at HPET lines. HPET is mapped to 0xfed00000.
> > Size of ivshmem is 32MB. During pci enumeration ivshmem will corrupt the range from 0xfe000000 - 0xffffffff.
> > It overlaps HPET memory. When Linux does late_hpet init, it finds garbage and this is causing panic.
> >
> 
> Let me see if I get this right: during BAR sizing, the guest sets the
> BAR to ~1, which means 4GB-32MB -> 4GB, which overlaps the HPET.  If so,
> that's expected behaviour.

Yes BAR sizing temporarily sets the BAR to an invalid value then
restores it.  What I don't understand is how come something accesses the
HPET range in between.

> If the guest doesn't want this memory there,
> it should disable mmio.

Recent kernels do this for most devices, but not for
platform devices.

> -- 
> error compiling committee.c: too many arguments to function

  reply	other threads:[~2012-01-26 14:04 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-25  5:46 [Qemu-devel] [RFC/PATCH] Fix guest OS panic when 64bit BAR is present Alexey Korolev
2012-01-25 12:51 ` Michael S. Tsirkin
2012-01-26  3:20   ` Alexey Korolev
2012-01-25 15:38 ` Michael S. Tsirkin
2012-01-25 18:59   ` Alex Williamson
2012-01-26  3:19     ` Alexey Korolev
2012-01-26 13:51       ` Avi Kivity
2012-01-26 14:05         ` Michael S. Tsirkin [this message]
2012-01-26 14:33           ` Avi Kivity
2012-01-26  9:14 ` Michael S. Tsirkin
2012-01-26 13:52   ` Avi Kivity
2012-01-26 14:36     ` Michael S. Tsirkin
2012-01-26 15:12       ` Avi Kivity
2012-01-27  4:42         ` Alexey Korolev
2012-01-31  9:40           ` Avi Kivity
2012-01-31  9:43             ` Avi Kivity
2012-02-01  5:44               ` Alexey Korolev
2012-02-01  7:04                 ` Michael S. Tsirkin
2012-02-02  2:22                   ` Alexey Korolev
2012-01-31 10:51           ` Avi Kivity
2012-01-27  4:40       ` Alexey Korolev

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