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Date:   Tue, 18 Jan 2022 16:35:26 +0000
From:   Alexandru Elisei <alexandru.elisei@arm.com>
To:     Marc Zyngier <maz@kernel.org>
Cc:     linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu,
        kvm@vger.kernel.org, Andre Przywara <andre.przywara@arm.com>,
        Christoffer Dall <christoffer.dall@arm.com>,
        Jintack Lim <jintack@cs.columbia.edu>,
        Haibo Xu <haibo.xu@linaro.org>,
        Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>,
        James Morse <james.morse@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        kernel-team@android.com
Subject: Re: [PATCH v5 15/69] KVM: arm64: nv: Inject HVC exceptions to the
 virtual EL2
Message-ID: <YebsTgBggC8YcCOm@monolith.localdoman>
References: <20211129200150.351436-1-maz@kernel.org>
 <20211129200150.351436-16-maz@kernel.org>
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Hi Marc,

On Mon, Nov 29, 2021 at 08:00:56PM +0000, Marc Zyngier wrote:
> From: Jintack Lim <jintack.lim@linaro.org>
> 
> As we expect all PSCI calls from the L1 hypervisor to be performed
> using SMC when nested virtualization is enabled, it is clear that
> all HVC instruction from the VM (including from the virtual EL2)
> are supposed to handled in the virtual EL2.
> 
> Forward these to EL2 as required.
> 
> Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
> [maz: add handling of HCR_EL2.HCD]
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  arch/arm64/kvm/handle_exit.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
> index 275a27368a04..1fd1c6dfd6a0 100644
> --- a/arch/arm64/kvm/handle_exit.c
> +++ b/arch/arm64/kvm/handle_exit.c
> @@ -16,6 +16,7 @@
>  #include <asm/kvm_asm.h>
>  #include <asm/kvm_emulate.h>
>  #include <asm/kvm_mmu.h>
> +#include <asm/kvm_nested.h>
>  #include <asm/debug-monitors.h>
>  #include <asm/traps.h>
>  
> @@ -40,6 +41,16 @@ static int handle_hvc(struct kvm_vcpu *vcpu)
>  			    kvm_vcpu_hvc_get_imm(vcpu));
>  	vcpu->stat.hvc_exit_stat++;
>  
> +	/* Forward hvc instructions to the virtual EL2 if the guest has EL2. */
> +	if (nested_virt_in_use(vcpu)) {
> +		if (vcpu_read_sys_reg(vcpu, HCR_EL2) & HCR_HCD)
> +			kvm_inject_undefined(vcpu);
> +		else
> +			kvm_inject_nested_sync(vcpu, kvm_vcpu_get_esr(vcpu));
> +
> +		return 1;
> +	}

Looks good to me:

Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>

Thanks,
Alex

> +
>  	ret = kvm_hvc_call_handler(vcpu);
>  	if (ret < 0) {
>  		vcpu_set_reg(vcpu, 0, ~0UL);
> -- 
> 2.30.2
>