Re: [PATCH 4/4] kvm: i386: Add classic PCI device assignment

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2012-08-27 14:07, Andreas Färber wrote:
> Hi,
> 
> Am 27.08.2012 08:28, schrieb Jan Kiszka:
>> From: Jan Kiszka <jan.kiszka@siemens.com>
>>
>> This adds PCI device assignment for i386 targets using the classic KVM
>> interfaces. This version is 100% identical to what is being maintained
>> in qemu-kvm for several years and is supported by libvirt as well. It is
>> expected to remain relevant for another couple of years until kernels
>> without full-features and performance-wise equivalent VFIO support are
>> obsolete.
>>
>> A refactoring to-do that should be done in-tree is to model MSI and
>> MSI-X support via the generic PCI layer, similar to what VFIO is already
>> doing for MSI-X. This should improve the correctness and clean up the
>> code from duplicate logic.
>>
>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>> ---
>>  hw/kvm/Makefile.objs |    2 +-
>>  hw/kvm/pci-assign.c  | 1929 ++++++++++++++++++++++++++++++++++++++++++++++++++
>>  2 files changed, 1930 insertions(+), 1 deletions(-)
>>  create mode 100644 hw/kvm/pci-assign.c
> [...]
>> diff --git a/hw/kvm/pci-assign.c b/hw/kvm/pci-assign.c
>> new file mode 100644
>> index 0000000..9cce02c
>> --- /dev/null
>> +++ b/hw/kvm/pci-assign.c
>> @@ -0,0 +1,1929 @@
>> +/*
>> + * Copyright (c) 2007, Neocleus Corporation.
>> + *
>> + * This program is free software; you can redistribute it and/or modify it
>> + * under the terms and conditions of the GNU General Public License,
>> + * version 2, as published by the Free Software Foundation.
> 
> The downside of accepting this into qemu.git is that it gets us a huge
> blob of GPLv2-only code without history of contributors for GPLv2+
> relicensing...

The history is documented in qemu-kvm. I personally don't see it will
pay off going through this, but someone else may, and nothing will
prevent trying this at least. I can leave a comment.

BTW, VFIO will be GPLv2 only as well. If I understood Alex correctly, it
is too much derived from this code. IOW: There is probably no PCI
assignment without this restriction in the foreseeable future.

> 
>> + *
>> + * This program is distributed in the hope it will be useful, but WITHOUT
>> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
>> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
>> + * more details.
>> + *
>> + * You should have received a copy of the GNU General Public License along with
>> + * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
>> + * Place - Suite 330, Boston, MA 02111-1307 USA.
> 
> (Expect the usual GNU address reminder here.)

Will fix.

> 
>> + *
>> + *
>> + *  Assign a PCI device from the host to a guest VM.
>> + *
>> + *  Adapted for KVM by Qumranet.
>> + *
>> + *  Copyright (c) 2007, Neocleus, Alex Novik (alex@neocleus.com)
>> + *  Copyright (c) 2007, Neocleus, Guy Zana (guy@neocleus.com)
>> + *  Copyright (C) 2008, Qumranet, Amit Shah (amit.shah@qumranet.com)
>> + *  Copyright (C) 2008, Red Hat, Amit Shah (amit.shah@redhat.com)
>> + *  Copyright (C) 2008, IBM, Muli Ben-Yehuda (muli@il.ibm.com)
>> + */
>> +#include <stdio.h>
>> +#include <unistd.h>
>> +#include <sys/io.h>
>> +#include <sys/mman.h>
>> +#include <sys/types.h>
>> +#include <sys/stat.h>
>> +#include "hw/hw.h"
>> +#include "hw/pc.h"
>> +#include "qemu-error.h"
>> +#include "console.h"
>> +#include "hw/loader.h"
>> +#include "monitor.h"
>> +#include "range.h"
>> +#include "sysemu.h"
>> +#include "hw/pci.h"
>> +#include "hw/msi.h"
> 
>> +#include "kvm_i386.h"
> 
> Am I correct to understand we compile this only for i386 / x86_64?

This is correct.

> (apic.o in kvm/Makefile.objs hints in that direction) You may want to
> update the description in the comment above accordingly, also mentioning
> that this is some deprecated backwards-compatibility thing.

You mean in the header of pci-assign.c? Can do.

Jan

-- 
Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
Corporate Competence Center Embedded Linux