linux-kernel - Re: [PATCH 0/2] LoongArch: KVM: Restore guest PMU if it is enabled

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Message-ID: <CAAhV-H69wDWRoJEspck722fpRAeuS__7vWcGz1nEU5kDuz+Lww@mail.gmail.com>
Date: Fri, 7 Nov 2025 18:13:31 +0800
From: Huacai Chen <chenhuacai@...nel.org>
To: Bibo Mao <maobibo@...ngson.cn>
Cc: Xianglai Li <lixianglai@...ngson.cn>, Song Gao <gaosong@...ngson.cn>, kvm@...r.kernel.org, 
	loongarch@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/2] LoongArch: KVM: Restore guest PMU if it is enabled

Applied, thanks.

Huacai

On Fri, Oct 24, 2025 at 3:20 PM Bibo Mao <maobibo@...ngson.cn> wrote:
>
> On LoongArch system, guest PMU hardware is shared by guest and host
> and PMU interrupt is separated. PMU is pass-through to VM, and there is
> PMU context switch when exit to host and return to guest.
>
> There is optimiation to check whether PMU is enabled by guest. If not,
> it is not necessary to return to guest. However it is enabled, PMU
> context for guest need switch on. Now KVM_REQ_PMU notification is set
> on vcpu context switch, however it is missing if there is no vcpu context
> switch and PMU is used by guest VM.
>
> Also there is code cleanup about PMU checking on vCPU sched-on callback,
> since it is already checked on VM exit entry or VM PMU CSR access abort
> routine.
>
> Bibo Mao (2):
>   LoongArch: KVM: Restore guest PMU if it is enabled
>   LoongArch: KVM: Skip PMU checking on vCPU context switch
>
>  arch/loongarch/kvm/vcpu.c | 19 +++++++++----------
>  1 file changed, 9 insertions(+), 10 deletions(-)
>
>
> base-commit: 6fab32bb6508abbb8b7b1c5498e44f0c32320ed5
> --
> 2.39.3
>