From: Gerd Hoffmann <kraxel@redhat.com>
To: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Cc: vineshp@xilinx.com, peter.maydell@linaro.org,
qemu-devel@nongnu.org, john.williams@xilinx.com,
edgar.iglesias@gmail.com, afaerber@suse.de
Subject: Re: [Qemu-devel] [PATCH v2 11/11] usb/ehci: Put RAM in undefined MMIO regions
Date: Fri, 26 Oct 2012 14:36:07 +0200 [thread overview]
Message-ID: <508A83B7.8050401@redhat.com> (raw)
In-Reply-To: <0c11f3611c74b87c53cfff65ea24f8d6ec82f666.1351229557.git.peter.crosthwaite@xilinx.com>
On 10/26/12 07:47, Peter Crosthwaite wrote:
> Just put RAM regions in the unimplemented spaces in the MMIO region. These
> regions have undefined behaviour, but this at least stops QEMU from segfaulting
> when the guest bangs on these registers (and sucessfully fakes reading and
> writing the registers with no side effects).
Make that an io region, have the read() handler return 0xff, write
handler do nothing except maybe logging/tracing the access for debugging
purposes. That is more correct for unassigned mmio space than backing
by memory. Adding memory also breaks migration btw.
I somehow still think this should be handled one layer up (i.e. the
parent region) which could do the approximate arch-specific action.
Any chance the access you are seeing is at offset 0x68?
cheers,
Gerd
next prev parent reply other threads:[~2012-10-26 12:36 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-26 5:47 [Qemu-devel] [PATCH v2 00/11] Sysbus EHCI + Zynq USB Peter Crosthwaite
2012-10-26 5:47 ` [Qemu-devel] [PATCH v2 01/11] dma: Define dma_context_memory and use in sysbus-ohci Peter Crosthwaite
2012-10-26 5:47 ` [Qemu-devel] [PATCH v2 02/11] usb/ehci: Use class_data to init PCI variations Peter Crosthwaite
2012-10-26 5:47 ` [Qemu-devel] [PATCH v2 03/11] usb/ehci: parameterise the register region offsets Peter Crosthwaite
2012-10-26 5:47 ` [Qemu-devel] [PATCH v2 04/11] usb/ehci: Abstract away PCI DMA API Peter Crosthwaite
2012-10-26 5:47 ` [Qemu-devel] [PATCH v2 05/11] usb/ehci: seperate out PCIisms Peter Crosthwaite
2012-10-26 12:24 ` Gerd Hoffmann
2012-10-27 0:32 ` Peter Crosthwaite
2012-10-29 1:04 ` Peter Crosthwaite
2012-10-29 7:43 ` Gerd Hoffmann
2012-10-26 5:47 ` [Qemu-devel] [PATCH v2 06/11] usb/ehci: Add Sysbus Infrastructure Peter Crosthwaite
2012-10-26 5:47 ` [Qemu-devel] [PATCH v2 07/11] usb/ehci: Add Xilinx ps7 USB controller Peter Crosthwaite
2012-10-26 5:47 ` [Qemu-devel] [PATCH v2 08/11] xilinx_zynq: add USB controllers Peter Crosthwaite
2012-10-26 12:26 ` Gerd Hoffmann
2012-10-26 5:47 ` [Qemu-devel] [PATCH v2 09/11] usb/ehci: Guard definition of EHCI_DEBUG Peter Crosthwaite
2012-10-26 5:47 ` [Qemu-devel] [PATCH v2 10/11] usb/ehci: Debug mode compile fixes Peter Crosthwaite
2012-10-26 5:47 ` [Qemu-devel] [PATCH v2 11/11] usb/ehci: Put RAM in undefined MMIO regions Peter Crosthwaite
2012-10-26 8:37 ` Peter Maydell
2012-10-26 12:36 ` Gerd Hoffmann [this message]
2012-10-26 12:39 ` Peter Maydell
2012-10-27 16:08 ` Peter Crosthwaite
2012-10-27 0:42 ` Peter Crosthwaite
2012-10-29 7:44 ` Gerd Hoffmann
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=508A83B7.8050401@redhat.com \
--to=kraxel@redhat.com \
--cc=afaerber@suse.de \
--cc=edgar.iglesias@gmail.com \
--cc=john.williams@xilinx.com \
--cc=peter.crosthwaite@xilinx.com \
--cc=peter.maydell@linaro.org \
--cc=qemu-devel@nongnu.org \
--cc=vineshp@xilinx.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.