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Date:   Thu, 27 Jul 2023 15:39:27 +0200
From:   Lorenzo Pieralisi <lpieralisi@kernel.org>
To:     Guanghui Feng <guanghuifeng@linux.alibaba.com>
Cc:     guohanjun@huawei.com, sudeep.holla@arm.com, rafael@kernel.org,
        linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org, baolin.wang@linux.alibaba.com,
        alikernel-developer@linux.alibaba.com, will@kernel.org,
        catalin.marinas@arm.com
Subject: Re: [PATCH v3] ACPI/IORT: Remove erroneous id_count check in
 iort_node_get_rmr_info()
Message-ID: <ZMJzj2oe0B2Qp8vp@lpieralisi>
References: <1689593625-45213-1-git-send-email-guanghuifeng@linux.alibaba.com>
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[+Catalin, Will]

On Mon, Jul 17, 2023 at 07:33:45PM +0800, Guanghui Feng wrote:
> According to the ARM IORT specifications DEN 0049 issue E,
> the "Number of IDs" field in the ID mapping format reports
> the number of IDs in the mapping range minus one.
> 
> In iort_node_get_rmr_info(), we erroneously skip ID mappings
> whose "Number of IDs" equal to 0, resulting in valid mapping
> nodes with a single ID to map being skipped, which is wrong.
> 
> Fix iort_node_get_rmr_info() by removing the bogus id_count
> check.
> 
> Fixes: 491cf4a6735a ("ACPI/IORT: Add support to retrieve IORT RMR reserved regions")
> Signed-off-by: Guanghui Feng <guanghuifeng@linux.alibaba.com>
> ---
>  drivers/acpi/arm64/iort.c | 3 ---
>  1 file changed, 3 deletions(-)

Acked-by: Lorenzo Pieralisi <lpieralisi@kernel.org>

Catalin/Will,

can you pick this up please ?

Thanks,
Lorenzo

> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> index 3631230..56d8873 100644
> --- a/drivers/acpi/arm64/iort.c
> +++ b/drivers/acpi/arm64/iort.c
> @@ -1007,9 +1007,6 @@ static void iort_node_get_rmr_info(struct acpi_iort_node *node,
>  	for (i = 0; i < node->mapping_count; i++, map++) {
>  		struct acpi_iort_node *parent;
>  
> -		if (!map->id_count)
> -			continue;
> -
>  		parent = ACPI_ADD_PTR(struct acpi_iort_node, iort_table,
>  				      map->output_reference);
>  		if (parent != iommu)
> -- 
> 1.8.3.1
>