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From:   "bibo, mao" <bibo.mao@gmail.com>
Message-ID: <b55f4665-1e2b-30fe-fb29-ae8856227275@loongson.cn>
Date:   Tue, 13 Jun 2023 20:56:32 +0800
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Subject: Re: [PATCH v13 08/30] LoongArch: KVM: Implement vcpu handle exit
 interface
To:     Tianrui Zhao <zhaotianrui@loongson.cn>
Cc:     Paolo Bonzini <pbonzini@redhat.com>,
        Huacai Chen <chenhuacai@kernel.org>,
        WANG Xuerui <kernel@xen0n.name>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        loongarch@lists.linux.dev, Jens Axboe <axboe@kernel.dk>,
        Mark Brown <broonie@kernel.org>,
        Alex Deucher <alexander.deucher@amd.com>,
        Oliver Upton <oliver.upton@linux.dev>,
        Xi Ruoyao <xry111@xry111.site>, tangyouling@loongson.cn,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org
References: <20230609090832.2131037-1-zhaotianrui@loongson.cn>
 <20230609090832.2131037-9-zhaotianrui@loongson.cn>
In-Reply-To: <20230609090832.2131037-9-zhaotianrui@loongson.cn>
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Reviewed-by: Bibo Mao <maobibo@loongson.cn>

Regards
Bibo, Mao

在 2023/6/9 17:08, Tianrui Zhao 写道:
> Implement vcpu handle exit interface, getting the exit code by ESTAT
> register and using kvm exception vector to handle it.
> 
> Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn>
> ---
>   arch/loongarch/kvm/vcpu.c | 45 +++++++++++++++++++++++++++++++++++++++
>   1 file changed, 45 insertions(+)
> 
> diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
> index eba5c07b8be3..a45e9d9efe5b 100644
> --- a/arch/loongarch/kvm/vcpu.c
> +++ b/arch/loongarch/kvm/vcpu.c
> @@ -52,6 +52,51 @@ static void kvm_pre_enter_guest(struct kvm_vcpu *vcpu)
>   	vcpu->arch.aux_inuse &= ~KVM_LARCH_CSR;
>   }
>   
> +/*
> + * Return 1 for resume guest and "<= 0" for resume host.
> + */
> +static int _kvm_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
> +{
> +	unsigned long exst = vcpu->arch.host_estat;
> +	u32 intr = exst & 0x1fff; /* ignore NMI */
> +	u32 exccode = (exst & CSR_ESTAT_EXC) >> CSR_ESTAT_EXC_SHIFT;
> +	int ret = RESUME_GUEST;
> +
> +	vcpu->mode = OUTSIDE_GUEST_MODE;
> +
> +	/* Set a default exit reason */
> +	run->exit_reason = KVM_EXIT_UNKNOWN;
> +
> +	local_irq_enable();
> +	guest_state_exit_irqoff();
> +
> +	trace_kvm_exit(vcpu, exccode);
> +	if (exccode) {
> +		ret = _kvm_handle_fault(vcpu, exccode);
> +	} else {
> +		WARN(!intr, "vm exiting with suspicious irq\n");
> +		++vcpu->stat.int_exits;
> +	}
> +
> +	cond_resched();
> +	local_irq_disable();
> +
> +	if (ret == RESUME_HOST)
> +		return ret;
> +
> +	/* Only check for signals if not already exiting to userspace */
> +	if (signal_pending(current)) {
> +		vcpu->run->exit_reason = KVM_EXIT_INTR;
> +		++vcpu->stat.signal_exits;
> +		return -EINTR;
> +	}
> +
> +	kvm_pre_enter_guest(vcpu);
> +	trace_kvm_reenter(vcpu);
> +	guest_state_enter_irqoff();
> +	return RESUME_GUEST;
> +}
> +
>   int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
>   {
>   	unsigned long timer_hz;