linux-kernel - Re: [PATCH v5 04/23] irqchip/gic-v4.1: Wait for completion of redistributor's INVALL operation

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Date:   Fri, 20 Mar 2020 15:23:49 +0100
From:   Auger Eric <eric.auger@...hat.com>
To:     Marc Zyngier <maz@...nel.org>,
        linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Jason Cooper <jason@...edaemon.net>,
        Robert Richter <rrichter@...vell.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Zenghui Yu <yuzenghui@...wei.com>,
        James Morse <james.morse@....com>,
        Julien Thierry <julien.thierry.kdev@...il.com>,
        Suzuki K Poulose <suzuki.poulose@....com>
Subject: Re: [PATCH v5 04/23] irqchip/gic-v4.1: Wait for completion of
 redistributor's INVALL operation

Hi,

On 3/4/20 9:33 PM, Marc Zyngier wrote:
> From: Zenghui Yu <yuzenghui@...wei.com>
> 
> In GICv4.1, we emulate a guest-issued INVALL command by a direct write
> to GICR_INVALLR.  Before we finish the emulation and go back to guest,
> let's make sure the physical invalidate operation is actually completed
> and no stale data will be left in redistributor. Per the specification,
> this can be achieved by polling the GICR_SYNCR.Busy bit (to zero).
> 
> Signed-off-by: Zenghui Yu <yuzenghui@...wei.com>
> Signed-off-by: Marc Zyngier <maz@...nel.org>
> Link: https://lore.kernel.org/r/20200302092145.899-1-yuzenghui@huawei.com
Reviewed-by: Eric Auger <eric.auger@...hat.com>

Thanks

Eric
> ---
>  drivers/irqchip/irq-gic-v3-its.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> index 1af713990123..c84370245bea 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -3827,6 +3827,8 @@ static void its_vpe_4_1_invall(struct its_vpe *vpe)
>  	/* Target the redistributor this vPE is currently known on */
>  	rdbase = per_cpu_ptr(gic_rdists->rdist, vpe->col_idx)->rd_base;
>  	gic_write_lpir(val, rdbase + GICR_INVALLR);
> +
> +	wait_for_syncr(rdbase);
>  }
>  
>  static int its_vpe_4_1_set_vcpu_affinity(struct irq_data *d, void *vcpu_info)
>