linux-kernel - Re: [PATCH v12 07/31] LoongArch: KVM: Implement vcpu run interface

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Date:   Mon, 5 Jun 2023 20:53:31 +0800
From:   "bibo, mao" <maobibo@...ngson.cn>
To:     Tianrui Zhao <zhaotianrui@...ngson.cn>,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Huacai Chen <chenhuacai@...nel.org>,
        WANG Xuerui <kernel@...0n.name>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        loongarch@...ts.linux.dev, Jens Axboe <axboe@...nel.dk>,
        Mark Brown <broonie@...nel.org>,
        Alex Deucher <alexander.deucher@....com>,
        Oliver Upton <oliver.upton@...ux.dev>,
        Xi Ruoyao <xry111@...111.site>
Subject: Re: [PATCH v12 07/31] LoongArch: KVM: Implement vcpu run interface



在 2023/5/30 09:51, Tianrui Zhao 写道:
> Implement vcpu run interface, handling mmio, iocsr reading fault
> and deliver interrupt, lose fpu before vcpu enter guest.
> 
> Signed-off-by: Tianrui Zhao <zhaotianrui@...ngson.cn>
> ---
>  arch/loongarch/kvm/vcpu.c | 86 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 86 insertions(+)
> 
> diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
> index 24b5b00266a1..eca8b96a3e6e 100644
> --- a/arch/loongarch/kvm/vcpu.c
> +++ b/arch/loongarch/kvm/vcpu.c
> @@ -17,6 +17,44 @@ int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id)
>  	return 0;
>  }
>  
> +/* Returns 1 if the guest TLB may be clobbered */
> +static int _kvm_check_requests(struct kvm_vcpu *vcpu, int cpu)
> +{
> +	int ret = 0;
> +
> +	if (!kvm_request_pending(vcpu))
> +		return 0;
> +
> +	if (kvm_check_request(KVM_REQ_TLB_FLUSH, vcpu)) {
> +		/* Drop vpid for this vCPU */
> +		vcpu->arch.vpid = 0;
> +		/* This will clobber guest TLB contents too */
> +		ret = 1;
> +	}
> +
> +	return ret;
> +}
can parameter cpu in function _kvm_check_requests be removed since it is not used here?

Regards
Bibo, Mao
> +
> +static void kvm_pre_enter_guest(struct kvm_vcpu *vcpu)
> +{
> +	int cpu;
> +
> +	/*
> +	 * handle vcpu timer, interrupts, check requests and
> +	 * check vmid before vcpu enter guest
> +	 */
> +	kvm_acquire_timer(vcpu);
> +	_kvm_deliver_intr(vcpu);
> +	/* make sure the vcpu mode has been written */
> +	smp_store_mb(vcpu->mode, IN_GUEST_MODE);
> +	cpu = smp_processor_id();
> +	_kvm_check_requests(vcpu, cpu);
> +	_kvm_check_vmid(vcpu, cpu);
> +	vcpu->arch.host_eentry = csr_read64(LOONGARCH_CSR_EENTRY);
> +	/* clear KVM_LARCH_CSR as csr will change when enter guest */
> +	vcpu->arch.aux_inuse &= ~KVM_LARCH_CSR;
> +}
> +
>  int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
>  {
>  	unsigned long timer_hz;
> @@ -86,3 +124,51 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
>  			context->last_vcpu = NULL;
>  	}
>  }
> +
> +int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
> +{
> +	int r = -EINTR;
> +	struct kvm_run *run = vcpu->run;
> +
> +	vcpu_load(vcpu);
> +
> +	kvm_sigset_activate(vcpu);
> +
> +	if (vcpu->mmio_needed) {
> +		if (!vcpu->mmio_is_write)
> +			_kvm_complete_mmio_read(vcpu, run);
> +		vcpu->mmio_needed = 0;
> +	}
> +
> +	if (run->exit_reason == KVM_EXIT_LOONGARCH_IOCSR) {
> +		if (!run->iocsr_io.is_write)
> +			_kvm_complete_iocsr_read(vcpu, run);
> +	}
> +
> +	/* clear exit_reason */
> +	run->exit_reason = KVM_EXIT_UNKNOWN;
> +	if (run->immediate_exit)
> +		goto out;
> +
> +	lose_fpu(1);
> +
> +	local_irq_disable();
> +	guest_timing_enter_irqoff();
> +
> +	kvm_pre_enter_guest(vcpu);
> +	trace_kvm_enter(vcpu);
> +
> +	guest_state_enter_irqoff();
> +	r = kvm_loongarch_ops->enter_guest(run, vcpu);
> +
> +	/* guest_state_exit_irqoff() already done.  */
> +	trace_kvm_out(vcpu);
> +	guest_timing_exit_irqoff();
> +	local_irq_enable();
> +
> +out:
> +	kvm_sigset_deactivate(vcpu);
> +
> +	vcpu_put(vcpu);
> +	return r;
> +}