linux-kernel - Re: [PATCH 1/1] iommu/vt-d: Correctly check format of page table in debugfs

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Date:   Fri, 9 Aug 2019 13:36:57 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     Joerg Roedel <joro@...tes.org>,
        David Woodhouse <dwmw2@...radead.org>
Cc:     baolu.lu@...ux.intel.com, ashok.raj@...el.com,
        jacob.jun.pan@...el.com, kevin.tian@...el.com,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        Jacob Pan <jacob.jun.pan@...ux.intel.com>,
        Sai Praneeth <sai.praneeth.prakhya@...el.com>
Subject: Re: [PATCH 1/1] iommu/vt-d: Correctly check format of page table in
 debugfs

Hi Joerg,

Just a friendly reminder. What do you think of this fix?

Best regards,
Lu Baolu

On 7/20/19 10:01 AM, Lu Baolu wrote:
> PASID support and enable bit in the context entry isn't the right
> indicator for the type of tables (legacy or scalable mode). Check
> the DMA_RTADDR_SMT bit in the root context pointer instead.
> 
> Cc: Ashok Raj <ashok.raj@...el.com>
> Cc: Jacob Pan <jacob.jun.pan@...ux.intel.com>
> Cc: Kevin Tian <kevin.tian@...el.com>
> Cc: Sai Praneeth <sai.praneeth.prakhya@...el.com>
> Fixes: dd5142ca5d24b ("iommu/vt-d: Add debugfs support to show scalable mode DMAR table internals")
> Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
> ---
>   drivers/iommu/intel-iommu-debugfs.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/intel-iommu-debugfs.c b/drivers/iommu/intel-iommu-debugfs.c
> index 73a552914455..e31c3b416351 100644
> --- a/drivers/iommu/intel-iommu-debugfs.c
> +++ b/drivers/iommu/intel-iommu-debugfs.c
> @@ -235,7 +235,7 @@ static void ctx_tbl_walk(struct seq_file *m, struct intel_iommu *iommu, u16 bus)
>   		tbl_wlk.ctx_entry = context;
>   		m->private = &tbl_wlk;
>   
> -		if (pasid_supported(iommu) && is_pasid_enabled(context)) {
> +		if (dmar_readq(iommu->reg + DMAR_RTADDR_REG) & DMA_RTADDR_SMT) {
>   			pasid_dir_ptr = context->lo & VTD_PAGE_MASK;
>   			pasid_dir_size = get_pasid_dir_size(context);
>   			pasid_dir_walk(m, pasid_dir_ptr, pasid_dir_size);
>