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[Qemu-devel] Re: start qemu failed with --enable-kvm -vga std
From: |
Jan Kiszka |
Subject: |
[Qemu-devel] Re: start qemu failed with --enable-kvm -vga std |
Date: |
Wed, 08 Apr 2009 18:34:26 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
Glauber Costa wrote:
> On Wed, Apr 8, 2009 at 10:12 AM, Anthony Liguori <address@hidden> wrote:
>> Peng Huang wrote:
>>> Hi,
>>>
>>> The HEAD version qemu can not execute a VM with --enable-kvm -vga std or
>>> -vga vmware on kernel 2.6.29.1-46.fc11.x86_64. I found it is because of qemu
>>> call cpu_register_physical_memory with a wrong size. Below patch can fix it
>>> on my box. Please test it.
>> Glauber came up with a similar patch for kvm-userspace and is currently
>> attempting to root cause the issue.
>
> I believe this is in fact the root cause. KVM slot management code
> probably require
> memory to be page aligned. By trying to register a region that is not
> page aligned,
> the ioctl may fail. I, however, did not see this happening in qemu
> upstream (only kvm-userspace),
> and have absolutely no idea about why. But the patch makes perfect sense to
> me.
>
But this really sounds like a limitation that should better be fixed in
the kvm layer, not the device/machine code.
We only map ROM regions here. So rounding them up/down and sending
properly aligned requests to the kernel should finally have the same
result for all involved pages. Only if non-compatible regions overlap
due to such roundings, we should bail out - and start to consider
changing device code.
My next free time slot is reserved now for the anyway required
enhancement of kvm's slot management in qemu. kvm-userspace could catch
up afterwards (finally fixing its broken text console after reset...).
Jan
--
Siemens AG, Corporate Technology, CT SE 2
Corporate Competence Center Embedded Linux
- [Qemu-devel] start qemu failed with --enable-kvm -vga std, Peng Huang, 2009/04/07
- Re: [Qemu-devel] start qemu failed with --enable-kvm -vga std, Paul Brook, 2009/04/08
- Re: [Qemu-devel] start qemu failed with --enable-kvm -vga std, Anthony Liguori, 2009/04/08
- Re: [Qemu-devel] start qemu failed with --enable-kvm -vga std, Glauber Costa, 2009/04/08
- [Qemu-devel] Re: start qemu failed with --enable-kvm -vga std,
Jan Kiszka <=
- Re: [Qemu-devel] Re: start qemu failed with --enable-kvm -vga std, Glauber Costa, 2009/04/08
- [Qemu-devel] Re: start qemu failed with --enable-kvm -vga std, Jan Kiszka, 2009/04/08
- Re: [Qemu-devel] Re: start qemu failed with --enable-kvm -vga std, Glauber Costa, 2009/04/08
- [Qemu-devel] Re: start qemu failed with --enable-kvm -vga std, Jan Kiszka, 2009/04/08
- Re: [Qemu-devel] Re: start qemu failed with --enable-kvm -vga std, Glauber Costa, 2009/04/08
- Re: [Qemu-devel] Re: start qemu failed with --enable-kvm -vga std, Glauber Costa, 2009/04/08
- Re: [Qemu-devel] Re: start qemu failed with --enable-kvm -vga std, M. Warner Losh, 2009/04/08
- Re: [Qemu-devel] Re: start qemu failed with --enable-kvm -vga std, Glauber Costa, 2009/04/08
- Re: [Qemu-devel] Re: start qemu failed with --enable-kvm -vga std, M. Warner Losh, 2009/04/08
- Re: [Qemu-devel] Re: start qemu failed with --enable-kvm -vga std, Paul Brook, 2009/04/08