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Re: [RFC PATCH 01/13] machine: Add mirrorvcpus=N suboption to -smp
From: |
Eric Blake |
Subject: |
Re: [RFC PATCH 01/13] machine: Add mirrorvcpus=N suboption to -smp |
Date: |
Mon, 16 Aug 2021 16:23:14 -0500 |
User-agent: |
NeoMutt/20210205-719-68949a |
On Mon, Aug 16, 2021 at 01:26:45PM +0000, Ashish Kalra wrote:
> From: Dov Murik <dovmurik@linux.vnet.ibm.com>
>
> Add a notion of mirror vcpus to CpuTopology, which will allow to
> designate a few vcpus (normally 1) for running the guest
> migration handler (MH).
>
> Example usage for starting a 4-vcpu guest, of which 1 vcpu is marked as
> mirror vcpu.
>
> qemu-system-x86_64 -smp 4,mirrorvcpus=1 ...
>
> Signed-off-by: Dov Murik <dovmurik@linux.vnet.ibm.com>
> Co-developed-by: Ashish Kalra <ashish.kalra@amd.com>
> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
> ---
> +++ b/qapi/machine.json
> @@ -1303,6 +1303,8 @@
> #
> # @maxcpus: maximum number of hotpluggable virtual CPUs in the virtual
> machine
> #
> +# @mirrorvcpus: maximum number of mirror virtual CPUs in the virtual machine
> +#
Needs a '(since 6.2)' tag.
> # Since: 6.1
> ##
> { 'struct': 'SMPConfiguration', 'data': {
> @@ -1311,4 +1313,5 @@
> '*dies': 'int',
> '*cores': 'int',
> '*threads': 'int',
> - '*maxcpus': 'int' } }
> + '*maxcpus': 'int',
> + '*mirrorvcpus': 'int' } }
Is this really the right place to be adding it? The rest of this
struct feels like things that advertise what bare metal can do, and
therefore what we are emulating. But bare metal can't do mirrors -
that's something that is completely in the realm of emulation only.
If I understand the cover letter, the guest shouldn't be able to
detect that mirroring exists, which is different from how the guest
DOES detect how many dies, cores, and threads are available to use.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
- [RFC PATCH 00/13] Add support for Mirror VM., Ashish Kalra, 2021/08/16
- [RFC PATCH 01/13] machine: Add mirrorvcpus=N suboption to -smp, Ashish Kalra, 2021/08/16
- Re: [RFC PATCH 01/13] machine: Add mirrorvcpus=N suboption to -smp,
Eric Blake <=
- [RFC PATCH 02/13] hw/boards: Add mirror_vcpu flag to CPUArchId, Ashish Kalra, 2021/08/16
- [RFC PATCH 03/13] hw/i386: Mark mirror vcpus in possible_cpus, Ashish Kalra, 2021/08/16
- [RFC PATCH 04/13] hw/acpi: Don't include mirror vcpus in ACPI tables, Ashish Kalra, 2021/08/16
- [RFC PATCH 05/13] cpu: Add boolean mirror_vcpu field to CPUState, Ashish Kalra, 2021/08/16
- [RFC PATCH 06/13] hw/i386: Set CPUState.mirror_vcpu=true for mirror vcpus, Ashish Kalra, 2021/08/16
- [RFC PATCH 07/13] kvm: Add Mirror VM ioctl and enable cap interfaces., Ashish Kalra, 2021/08/16
- [RFC PATCH 08/13] kvm: Add Mirror VM support., Ashish Kalra, 2021/08/16
- [RFC PATCH 09/13] kvm: create Mirror VM and share primary VM's encryption context., Ashish Kalra, 2021/08/16
- [RFC PATCH 10/13] softmmu/cpu: Skip mirror vcpu's for pause, resume and synchronization., Ashish Kalra, 2021/08/16
- [RFC PATCH 11/13] kvm/apic: Disable in-kernel APIC support for mirror vcpu's., Ashish Kalra, 2021/08/16