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Date: Mon, 11 Sep 2023 23:57:39 +0800
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Subject: Re: [PATCH 4/5] KVM: arm64: vgic-v3: Refactor GICv3 SGI generation
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To: Marc Zyngier <maz@kernel.org>
Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
 kvm@vger.kernel.org, James Morse <james.morse@arm.com>,
 Suzuki K Poulose <suzuki.poulose@arm.com>,
 Oliver Upton <oliver.upton@linux.dev>, Zenghui Yu <yuzenghui@huawei.com>,
 Xu Zhao <zhaoxu.35@bytedance.com>
References: <20230907100931.1186690-1-maz@kernel.org>
 <20230907100931.1186690-5-maz@kernel.org>
 <fd96f034-b7ca-c1bd-a94e-06f8e84e52a7@linux.dev>
 <87ledd51tu.wl-maz@kernel.org>
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From: Zenghui Yu <zenghui.yu@linux.dev>
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On 2023/9/11 02:18, Marc Zyngier wrote:
> On Sun, 10 Sep 2023 17:25:36 +0100,
> Zenghui Yu <zenghui.yu@linux.dev> wrote:
>>
>> Hi Marc,
>>
>> I asked because it seems that in kvm/arm64 we always use
>> kvm_get_vcpu(kvm, i) to obtain the kvm_vcpu pointer, even if *i* is
>> sometimes essentially provided by userspace..
> 
> Huh, this is incredibly dodgy. I had a go at a few occurrences (see
> below), but this is hardly a complete list.

Another case is all kvm_get_vcpu(kvm, target_addr) in the vgic-its
emulation code. As we expose GITS_TYPER.PTA=0 to guest, which indicates
that the target address corresponds to the PE number specified by
GICR_TYPER.Processor_Number, which is now encoded as vcpu->vcpu_id.

Thanks,
Zenghui