From: Paolo Bonzini <pbonzini@redhat.com>
To: Kevin O'Connor <kevin@koconnor.net>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
qemu-devel@nongnu.org, dgilbert@redhat.com,
Juan Quintela <quintela@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 2/5] exec: qemu_ram_alloc_device, qemu_ram_resize
Date: Wed, 19 Nov 2014 18:01:06 +0100 [thread overview]
Message-ID: <546CCCD2.8050507@redhat.com> (raw)
In-Reply-To: <20141119162712.GA19365@morn.localdomain>
On 19/11/2014 17:27, Kevin O'Connor wrote:
> On Wed, Nov 19, 2014 at 02:44:32PM +0100, Paolo Bonzini wrote:
>> So:
>>
>> qemu-2.0 -M pc-2.0 -> qemu-2.2 -M pc-2.0
>>
>> uses 2.0 BIOS
>>
>> qemu-2.2 -M pc-2.0 -> qemu-2.0 -M pc-2.0
>>
>> uses 2.2 BIOS
>>
>> Both should work, in general. BIOS is rarely the reason for
>> incompatibilities. However, breakage can happen, for example I know
>> that RHEL7 SeaBIOS does not work on RHEL6. RHEL6 SeaBIOS works on
>> RHEL7, but it needs a couple workarounds.
>
> Do you know why that is? We do try to make SeaBIOS backwards
> compatible with older versions of QEMU.
For RHEL6-on-RHEL7 SeaBIOS was violating the virtio-scsi spec, but QEMU
happened to support the broken case until recently. When I was told
that the broken case stopped working, I added a workaround.
I don't know why RHEL7 SeaBIOS does not work on RHEL6. But note that
it's a really old version (0.12). I guess one could try compiling
various QEMU versions and see where it broke, and then either debug or
bisect further. RHEL7 uses 1.5.3.
Paolo
next prev parent reply other threads:[~2014-11-19 17:01 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-17 20:08 [Qemu-devel] [PATCH 0/5] pc: make ROMs resizeable Michael S. Tsirkin
2014-11-17 20:08 ` [Qemu-devel] [PATCH 1/5] cpu: add cpu_physical_memory_clear_dirty_range_nocode Michael S. Tsirkin
2014-11-19 9:10 ` Juan Quintela
2014-11-17 20:08 ` [Qemu-devel] [PATCH 2/5] exec: qemu_ram_alloc_device, qemu_ram_resize Michael S. Tsirkin
2014-11-17 20:15 ` Michael S. Tsirkin
2014-11-18 6:03 ` Paolo Bonzini
2014-11-18 7:49 ` Michael S. Tsirkin
2014-11-19 9:19 ` Juan Quintela
2014-11-19 9:33 ` Michael S. Tsirkin
2014-11-19 10:11 ` Juan Quintela
2014-11-19 10:21 ` Michael S. Tsirkin
2014-11-19 10:45 ` Juan Quintela
2014-11-19 13:28 ` Michael S. Tsirkin
2014-11-19 13:44 ` Paolo Bonzini
2014-11-19 13:57 ` Juan Quintela
2014-11-19 14:13 ` Dr. David Alan Gilbert
2014-11-19 14:22 ` Paolo Bonzini
2014-11-19 14:26 ` Dr. David Alan Gilbert
2014-11-19 14:28 ` Paolo Bonzini
2014-11-19 14:59 ` Dr. David Alan Gilbert
2014-11-19 15:38 ` Michael S. Tsirkin
2014-11-19 15:53 ` Dr. David Alan Gilbert
2014-11-19 14:22 ` Juan Quintela
2014-11-19 14:20 ` Paolo Bonzini
2014-11-19 16:39 ` Juan Quintela
2014-11-19 16:56 ` Paolo Bonzini
2014-11-19 16:27 ` Kevin O'Connor
2014-11-19 17:01 ` Paolo Bonzini [this message]
2014-11-20 8:12 ` Gerd Hoffmann
2014-11-20 10:00 ` Paolo Bonzini
2014-11-19 13:49 ` Juan Quintela
2014-11-19 13:51 ` Paolo Bonzini
2014-11-19 14:03 ` Juan Quintela
2014-11-19 14:11 ` Paolo Bonzini
2014-11-19 14:16 ` Dr. David Alan Gilbert
2014-11-19 14:28 ` Paolo Bonzini
2014-11-19 14:20 ` Juan Quintela
2014-11-19 15:43 ` Michael S. Tsirkin
2014-11-19 10:16 ` Markus Armbruster
2014-11-19 10:30 ` Michael S. Tsirkin
2014-11-19 10:50 ` Juan Quintela
2014-11-19 13:36 ` Michael S. Tsirkin
2014-11-19 13:51 ` Juan Quintela
2014-11-19 15:46 ` Michael S. Tsirkin
2014-11-19 16:45 ` Juan Quintela
2014-11-19 18:28 ` Paolo Bonzini
2014-11-20 13:35 ` Markus Armbruster
2014-11-20 14:04 ` Michael S. Tsirkin
2014-11-24 13:48 ` Paolo Bonzini
2014-11-19 13:58 ` Peter Maydell
2014-11-19 14:07 ` Juan Quintela
2014-11-19 14:10 ` Peter Maydell
2014-11-19 14:18 ` Juan Quintela
2014-11-19 16:08 ` Stefan Hajnoczi
2014-11-19 14:19 ` Paolo Bonzini
2014-11-19 14:21 ` Peter Maydell
2014-11-19 14:30 ` Paolo Bonzini
2014-11-19 15:16 ` Michael S. Tsirkin
2014-11-19 16:50 ` Juan Quintela
2014-11-19 15:12 ` Michael S. Tsirkin
2014-11-19 15:04 ` Michael S. Tsirkin
2014-11-17 20:08 ` [Qemu-devel] [PATCH 3/5] arch_init: support resizing on incoming migration Michael S. Tsirkin
2014-11-17 20:08 ` [Qemu-devel] [PATCH 4/5] memory: interface to allocate device ram Michael S. Tsirkin
2014-11-17 20:21 ` Peter Maydell
2014-11-18 11:54 ` Michael S. Tsirkin
2014-11-17 20:09 ` [Qemu-devel] [PATCH 5/5] acpi-build: make ROMs device RAM, make them resizeable Michael S. Tsirkin
2014-11-17 20:11 ` [Qemu-devel] [PATCH 0/5] pc: make ROMs resizeable Michael S. Tsirkin
2014-11-19 7:29 ` Amit Shah
2014-11-18 14:47 ` Markus Armbruster
2014-11-18 15:00 ` Michael S. Tsirkin
2014-11-19 8:16 ` Markus Armbruster
2014-11-19 13:41 ` Michael S. Tsirkin
2014-11-19 7:31 ` Amit Shah
2014-11-19 8:15 ` Michael S. Tsirkin
2014-11-19 8:22 ` Amit Shah
2014-11-19 13:33 ` Michael S. Tsirkin
2014-11-19 13:52 ` Juan Quintela
2014-11-19 16:01 ` Michael S. Tsirkin
2014-11-19 13:52 ` Peter Maydell
2014-11-19 14:41 ` Paolo Bonzini
2014-11-19 15:34 ` Michael S. Tsirkin
2014-11-19 16:40 ` Juan Quintela
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