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To:     Zenghui Yu <yuzenghui@huawei.com>
Subject: Re: [PATCH v2] irqchip/gic-v3-its: Use the exact ITSList for VMOVP
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Date:   Fri, 25 Oct 2019 09:24:34 +0100
From:   Marc Zyngier <maz@kernel.org>
Cc:     <tglx@linutronix.de>, <jason@lakedaemon.net>,
        <kvmarm@lists.cs.columbia.edu>,
        <linux-arm-kernel@lists.infradead.org>,
        <wanghaibin.wang@huawei.com>, <jiayanlei@huawei.com>,
        LKML <linux-kernel@vger.kernel.org>
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On 2019-10-23 04:46, Zenghui Yu wrote:
> On a system without Single VMOVP support (say GITS_TYPER.VMOVP == 0),
> we will map vPEs only on ITSs that will actually control interrupts
> for the given VM.  And when moving a vPE, the VMOVP command will be
> issued only for those ITSs.
>
> But when issuing VMOVPs we seemed fail to present the exact ITSList
> to ITSs who are actually included in the synchronization operation.
> The its_list_map we're currently using includes all ITSs in the 
> system,
> even though some of them don't have the corresponding vPE mapping at 
> all.
>
> Introduce get_its_list() to get the per-VM its_list_map, to indicate
> which ITSs have vPE mappings for the given VM, and use this map as
> the expected ITSList when building VMOVP. This is hopefully a 
> performance
> gain not to do some synchronization with those unsuspecting ITSs.
> And initialize the whole command descriptor to zero at beginning, 
> since
> the seq_num and its_list should be RES0 when GITS_TYPER.VMOVP == 1.
>
> Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>

I've applied this as a fix for 5.4. In the future, please cc LKML on 
all
IRQ-related patches (as documented in MAINTAINERS).

         M.
-- 
Jazz is not dead. It just smells funny...