From: Laszlo Ersek <lersek@redhat.com>
To: Igor Mammedov <imammedo@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
"Richard Henderson" <rth@twiddle.net>,
"Philippe Mathieu-Daudé" <philmd@redhat.com>,
"qemu devel list" <qemu-devel@nongnu.org>,
"Eduardo Habkost" <ehabkost@redhat.com>
Subject: Re: [PATCH 3/4] hw/i386: add facility to expose CPU topology over fw-cfg
Date: Thu, 10 Oct 2019 18:23:00 +0200 [thread overview]
Message-ID: <0032ef80-4e75-5802-8a7a-098e9ff57cfa@redhat.com> (raw)
In-Reply-To: <20191010144812.20fd8b5d@redhat.com>
On 10/10/19 14:48, Igor Mammedov wrote:
> it doesn't really matter if it's ACPI blob or fw_cfg,
> what firmware needs is a table of possible CPUs with APIC IDs.
To repeat my previous point:
Not necessarily taking sides between "data table" and "register block",
but *if* we opt for "data table", then it *must* be fw_cfg.
> But if we go this route (i.e. not reuse CPU hotplug interface),
> the table alone is not enough, one would need to build a protocol
> between ACPI and firmware to communicate what CPUs to (un)hotplug.
That's for sure, yes -- for finding out what CPU has been hotplugged,
the hotplug SMI handler in the firmware has to look at the register
block no matter what.
The "data table" vs "register block" question only arises *afterwards*,
for translating the CPU selector (fetched from the register block) to
the APIC-ID domain. (The generic edk2 infrastructure requires APIC-IDs).
Thanks
Laszlo
next prev parent reply other threads:[~2019-10-10 16:32 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-08 10:52 [PATCH 0/4] hw/i386: pass "MachineState.smp.max_cpus" to OVMF Laszlo Ersek
2019-10-08 10:52 ` [PATCH 1/4] fw_cfg: bump file slots to 40 Laszlo Ersek
2019-10-08 10:52 ` [PATCH 2/4] target/i386: remove useless enable_compat_apic_id_mode() prototype Laszlo Ersek
2019-10-08 13:35 ` Philippe Mathieu-Daudé
2019-10-08 18:22 ` Laszlo Ersek
2019-10-08 10:52 ` [PATCH 3/4] hw/i386: add facility to expose CPU topology over fw-cfg Laszlo Ersek
2019-10-08 13:29 ` Philippe Mathieu-Daudé
2019-10-08 18:31 ` Laszlo Ersek
2019-10-08 15:59 ` Igor Mammedov
2019-10-09 21:01 ` Laszlo Ersek
2019-10-10 9:45 ` Igor Mammedov
2019-10-10 10:01 ` Michael S. Tsirkin
2019-10-10 12:48 ` Igor Mammedov
2019-10-10 16:23 ` Laszlo Ersek [this message]
2019-10-10 18:08 ` Michael S. Tsirkin
2019-10-11 6:50 ` Laszlo Ersek
2019-10-11 7:46 ` Laszlo Ersek
2019-10-10 16:15 ` Laszlo Ersek
2019-10-08 18:58 ` Laszlo Ersek
2019-10-09 11:13 ` Igor Mammedov
2019-10-09 21:03 ` Laszlo Ersek
2019-10-09 21:09 ` Eduardo Habkost
2019-10-08 10:52 ` [PATCH 4/4] hw/i386/pc: " Laszlo Ersek
2019-10-08 14:23 ` [PATCH 0/4] hw/i386: pass "MachineState.smp.max_cpus" to OVMF no-reply
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