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From: Salil Mehta via <qemu-devel@nongnu.org>
To: lixianglai <lixianglai@loongson.cn>,
	David Hildenbrand <david@redhat.com>,
	 "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Cc: "Salil Mehta" <salil.mehta@opnsrc.net>,
	"Xiaojuan Yang" <yangxiaojuan@loongson.cn>,
	"Song Gao" <gaosong@loongson.cn>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	"Igor Mammedov" <imammedo@redhat.com>,
	"Ani Sinha" <anisinha@redhat.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Richard Henderson" <richard.henderson@linaro.org>,
	"Eduardo Habkost" <eduardo@habkost.net>,
	"Marcel Apfelbaum" <marcel.apfelbaum@gmail.com>,
	"Philippe Mathieu-Daudé" <philmd@linaro.org>,
	"wangyanan (Y)" <wangyanan55@huawei.com>,
	"Daniel P. Berrangé" <berrange@redhat.com>,
	"Peter Xu" <peterx@redhat.com>, "Bibo Mao" <maobibo@loongson.cn>
Subject: RE: [PATCH v2 04/10] Introduce the CPU address space destruction function
Date: Tue, 26 Sep 2023 11:06:35 +0000	[thread overview]
Message-ID: <95d2f7e2d846417da5ebadc5ab8c7086@huawei.com> (raw)
In-Reply-To: <20eb8316-22a2-c812-7172-6bd9016877cc@loongson.cn>



> From: qemu-devel-bounces+salil.mehta=huawei.com@nongnu.org <qemu-devel-
> bounces+salil.mehta=huawei.com@nongnu.org> On Behalf Of lixianglai
> Sent: Thursday, September 14, 2023 2:01 PM
> To: David Hildenbrand <david@redhat.com>; qemu-devel@nongnu.org
> Cc: Salil Mehta <salil.mehta@opnsrc.net>; Xiaojuan Yang
> <yangxiaojuan@loongson.cn>; Song Gao <gaosong@loongson.cn>; Michael S.
> Tsirkin <mst@redhat.com>; Igor Mammedov <imammedo@redhat.com>; Ani Sinha
> <anisinha@redhat.com>; Paolo Bonzini <pbonzini@redhat.com>; Richard
> Henderson <richard.henderson@linaro.org>; Eduardo Habkost
> <eduardo@habkost.net>; Marcel Apfelbaum <marcel.apfelbaum@gmail.com>;
> Philippe Mathieu-Daudé <philmd@linaro.org>; wangyanan (Y)
> <wangyanan55@huawei.com>; Daniel P. Berrangé <berrange@redhat.com>; Peter
> Xu <peterx@redhat.com>; Bibo Mao <maobibo@loongson.cn>
> Subject: Re: [PATCH v2 04/10] Introduce the CPU address space destruction
> function
> 
> Hi David:
> 
> > On 12.09.23 04:11, xianglai li wrote:
> >> Introduce new function to destroy CPU address space resources
> >> for cpu hot-(un)plug.
> >>
> > How do other archs handle that? Or how are they able to get away
> > without destroying?
> >
> They do not remove the cpu address space, taking the X86 architecture as
> an example:
> 
> 1.Start the x86 VM:
> 
> ./qemu-system-x86_64 \
> -machine q35  \
> -cpu Broadwell-IBRS \
> -smp 1,maxcpus=100,sockets=100,cores=1,threads=1 \
> -m 4G \
> -drive file=~/anolis-8.8.qcow2  \
> -serial stdio   \
> -monitor telnet:localhost:4498,server,nowait   \
> -nographic
> 
> 2.Connect the qemu monitor
> 
> telnet 127.0.0.1 4498
> 
> info mtree
> 
> address-space: cpu-memory-0
> address-space: memory
>    0000000000000000-ffffffffffffffff (prio 0, i/o): system
>      0000000000000000-000000007fffffff (prio 0, ram): alias ram-below-4g
> @pc.ram 0000000000000000-000000007fffffff
>      0000000000000000-ffffffffffffffff (prio -1, i/o): pci
>        00000000000a0000-00000000000bffff (prio 1, i/o): vga-lowmem
> 
> 3.Perform cpu hot swap int qemu monitor
> 
> device_add
> Broadwell-IBRS-x86_64-cpu,socket-id=1,core-id=0,thread-id=0,id=cpu1
> device_del cpu1
> 
> info mtree
> 
> address-space: cpu-memory-0
> address-space: cpu-memory-1
> address-space: memory
>    0000000000000000-ffffffffffffffff (prio 0, i/o): system
>      0000000000000000-000000007fffffff (prio 0, ram): alias ram-below-4g
> @pc.ram 0000000000000000-000000007fffffff
>      0000000000000000-ffffffffffffffff (prio -1, i/o): pci
>        00000000000a0000-00000000000bffff (prio 1, i/o): vga-lowmem
> 
> 
>  From the above test, you can see whether the address space of cpu1 is
> residual after a cpu hot swap, and whether it is reasonable?
> 
> The address space destruction function of the CPU can be used to delete
> the residual address space of the CPU1.

Yes, it can be but I would interested to know if there is any problem
which might have gone unnoticed while doing it.

Many thanks
Salil.


  parent reply	other threads:[~2023-09-26 11:07 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-12  2:11 [PATCH v2 00/10] Adds CPU hot-plug support to Loongarch xianglai li
2023-09-12  2:11 ` [PATCH v2 01/10] Update ACPI GED framework to support vcpu hot-(un)plug xianglai li
2023-09-12  2:11 ` [PATCH v2 02/10] Update CPUs AML with cpu-(ctrl)dev change xianglai li
2023-09-12  2:11 ` [PATCH v2 03/10] make qdev_disconnect_gpio_out_named() public xianglai li
2023-09-12  8:10   ` Philippe Mathieu-Daudé
2023-09-15  7:00     ` lixianglai
2023-09-12  2:11 ` [PATCH v2 04/10] Introduce the CPU address space destruction function xianglai li
2023-09-12  7:00   ` David Hildenbrand
2023-09-14 13:00     ` lixianglai
2023-09-14 13:26       ` David Hildenbrand
2023-09-15  2:48         ` lixianglai
2023-09-15  2:53           ` lixianglai
2023-09-15  8:07             ` David Hildenbrand
2023-09-15  9:54               ` lixianglai
2023-09-15 14:19               ` Philippe Mathieu-Daudé
2023-09-15 15:22                 ` David Hildenbrand
2023-09-26 11:25                   ` Salil Mehta via
2023-09-26 11:21               ` Salil Mehta via
2023-09-26 11:55                 ` Salil Mehta via
2023-09-26 12:23                   ` David Hildenbrand
2023-09-26 12:32                     ` Salil Mehta via
2023-09-26 12:37                       ` David Hildenbrand
2023-09-26 12:44                         ` Salil Mehta via
2023-09-26 12:52                           ` David Hildenbrand
2023-09-27  2:16                   ` lixianglai
2023-09-26 11:11           ` Salil Mehta via
2023-09-26 11:06       ` Salil Mehta via [this message]
2023-09-26 11:03     ` Salil Mehta via
2023-09-12  2:11 ` [PATCH v2 05/10] Added CPU topology support for Loongarch xianglai li
2023-09-12  2:11 ` [PATCH v2 06/10] Optimize loongarch_irq_init function implementation xianglai li
2023-09-12  2:11 ` [PATCH v2 07/10] Add basic CPU hot-(un)plug support for Loongarch xianglai li
2023-09-12  2:11 ` [PATCH v2 08/10] Add support of *unrealize* for Loongarch cpu xianglai li
2023-09-12  2:11 ` [PATCH v2 09/10] Add generic event device for Loongarch xianglai li
2023-09-12  2:11 ` [PATCH v2 10/10] Update the ACPI table for the Loongarch CPU xianglai li
2023-09-12  9:08 ` [PATCH v2 00/10] Adds CPU hot-plug support to Loongarch Salil Mehta via
2023-09-13  3:52   ` lixianglai

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