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Re: [Qemu-arm] [PATCH v4 0/7] q35: add negotiable broadcast SMI
From: |
Laszlo Ersek |
Subject: |
Re: [Qemu-arm] [PATCH v4 0/7] q35: add negotiable broadcast SMI |
Date: |
Tue, 10 Jan 2017 17:19:31 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.6.0 |
On 01/10/17 17:05, Michael S. Tsirkin wrote:
> On Tue, Jan 10, 2017 at 04:23:41PM +0100, Laszlo Ersek wrote:
>> On 01/10/17 16:06, Michael S. Tsirkin wrote:
>>> On Thu, Dec 01, 2016 at 06:06:17PM +0100, Laszlo Ersek wrote:
>>>> * This is version 4 of the series; the last version was at
>>>> <http://lists.nongnu.org/archive/html/qemu-devel/2016-11/msg03582.html>.
>>>>
>>>> This version is practically a rewrite from scratch, seeking to address
>>>> the v3 feedback. Here's what the individual patches do:
>>>>
>>>> - Patch #1 rebases and extends Michael's "writeable fw_cfg blobs"
>>>> patch from Feb/March 2016. The changes relative to the original
>>>> patch are documented in the commit message (the code changes are
>>>> minimal).
>>>>
>>>> - Patches #2 and #3 turn the FW_CFG_FILE_SLOTS constant into a device
>>>> property, and expose the desired number of fw_cfg file slots to
>>>> board code. This is meant to address a concern raised by Paolo in
>>>> the v2 review
>>>>
>>>> <http://lists.nongnu.org/archive/html/qemu-devel/2016-11/msg03125.html>,
>>>> namely that we're about to run out of FW_CFG_FILE_SLOTS.
>>>>
>>>> - Patch #4 introduces the "pc-q35-2.9" and "pc-i440fx-2.9" machine
>>>> types, which are allowed to take advantage of the new default for
>>>> fw_cfg file slots (0x20 rather than 0x10).
>>>>
>>>> - Patch #5 introduces SMI feature negotiation via fw_cfg, with the
>>>> following new files:
>>>>
>>>> - etc/smi/host-features
>>>> - etc/smi/guest-features
>>>> - etc/smi/features-ok
>>>>
>>>> This is supposed to follow Michael's recommendation re: imitating
>>>> virtio
>>>>
>>>> <http://lists.nongnu.org/archive/html/qemu-devel/2016-11/msg03218.html>.
>>>>
>>>> The guest-features file is freely writeable by the guest (no write
>>>> callbacks in fw_cfg), and the feature validation & lockdown occurs
>>>> when the guest selects the features-ok file (for reading).
>>>>
>>>> Board code is allowed to choose the host feature bitmap to
>>>> advertise.
>>>>
>>>> This patch doesn't add any specific SMI features yet.
>>>>
>>>> - Patch #6 adds the ICH9_LPC_SMI_F_BROADCAST feature.
>>>>
>>>> - Patch #7 introduces the PCMachineClass.get_smi_host_features method,
>>>> and implements it for "pc-q35-2.9" and later. The idea is to tie the
>>>> SMI host features to machine types, and let the machine types
>>>> calculate their host features with code (i.e., not just a constant).
>>>>
>>>> In this patch, the "pc-q35-2.9" machine type exposes the
>>>> ICH9_LPC_SMI_F_BROADCAST feature iff (smp_cpus == max_cpus), that
>>>> is, when VCPU hotplug is not possible. (Also from Paolo's v3
>>>> feedback, in
>>>>
>>>> <http://lists.nongnu.org/archive/html/qemu-devel/2016-11/msg04919.html>.)
>>>>
>>>> * I've written the OVMF side patches too and tested them together
>>>> (including gdb / debug messages for "white box" testing).
>>>>
>>>> * Note that this version depends on the following PULL req from Michael:
>>>>
>>>> [Qemu-devel] [PULL 0/5] virtio, vhost, pc: fixes
>>>> http://lists.nongnu.org/archive/html/qemu-devel/2016-11/msg05503.html
>>>>
>>>> In particular on the following patch:
>>>> "loader: fix handling of custom address spaces when adding ROM blobs"
>>>>
>>>> Cc: "Gabriel L. Somlo" <address@hidden>
>>>> Cc: "Michael S. Tsirkin" <address@hidden>
>>>> Cc: Eduardo Habkost <address@hidden>
>>>> Cc: Gerd Hoffmann <address@hidden>
>>>> Cc: Igor Mammedov <address@hidden>
>>>> Cc: Michael Walle <address@hidden>
>>>> Cc: Paolo Bonzini <address@hidden>
>>>> Cc: Peter Maydell <address@hidden>
>>>> Cc: Shannon Zhao <address@hidden>
>>>> Cc: address@hidden
>>>>
>>>> Thanks
>>>> Laszlo
>>>
>>> So I reviewed fw cfg stuff, looks good to me.
>>
>> Thank you.
>>
>> I should note that Igor suggested / requested changes for patches #2 and
>> #3; the sub-threads start at
>>
>> http://lists.nongnu.org/archive/html/qemu-devel/2016-12/msg00695.html
>> msg-id: <address@hidden>
>>
>> http://lists.nongnu.org/archive/html/qemu-devel/2016-12/msg00706.html
>> msg-id: <address@hidden>
>>
>> I was about to rework the patches based on his feedback. Should we
>> resume those discussions?
>
> If you both agree, pls go ahead and make these changes.
Okay, will do.
>
>>> I'd prefer Paolo to review
>>> and merge broadcast SMI stuff as appropriate. Paolo, makes sense?
>>
>> If it helps, I can split the series into two "waves", and deal only with
>> fw_cfg first.
>>
>> Thanks!
>> Laszlo
>
> I don't mind either way.
I'll see then how I feel about splitting v5 when I'm ready to post it. :)
Thanks!
Laszlo