linux-kernel - Re: [PATCH 00/14] iommu: Move iommu

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Date:   Mon, 9 Mar 2020 17:32:02 +0100
From:   Joerg Roedel <joro@...tes.org>
To:     Jean-Philippe Brucker <jean-philippe@...aro.org>
Cc:     Hanjun Guo <guohanjun@...wei.com>,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, linux-mediatek@...ts.infradead.org,
        virtualization@...ts.linux-foundation.org,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Sudeep Holla <sudeep.holla@....com>,
        Rob Clark <robdclark@...il.com>, Sean Paul <sean@...rly.run>,
        Will Deacon <will@...nel.org>,
        Robin Murphy <robin.murphy@....com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Linuxarm <linuxarm@...wei.com>
Subject: Re: [PATCH 00/14] iommu: Move iommu_fwspec out of 'struct device'

Hi Jean-Philippe,

On Fri, Mar 06, 2020 at 11:09:55AM +0100, Jean-Philippe Brucker wrote:
> I think that's because patch 01/14 move the fwspec access too early. In 
> 
>                 err = pci_for_each_dma_alias(to_pci_dev(dev),
>                                              iort_pci_iommu_init, &info);
> 
>                 if (!err && iort_pci_rc_supports_ats(node))
>                         dev->iommu_fwspec->flags |= IOMMU_FWSPEC_PCI_RC_ATS;
> 
> the iommu_fwspec is only valid if iort_pci_iommu_init() initialized it
> successfully, if err == 0. The following might fix it:
> 
> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> index 0e981d7f3c7d..7d04424189df 100644
> --- a/drivers/acpi/arm64/iort.c
> +++ b/drivers/acpi/arm64/iort.c
> @@ -1015,7 +1015,7 @@ const struct iommu_ops *iort_iommu_configure(struct device *dev)
>  		return ops;
> 
>  	if (dev_is_pci(dev)) {
> -		struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> +		struct iommu_fwspec *fwspec;
>  		struct pci_bus *bus = to_pci_dev(dev)->bus;
>  		struct iort_pci_alias_info info = { .dev = dev };
> 
> @@ -1028,7 +1028,8 @@ const struct iommu_ops *iort_iommu_configure(struct device *dev)
>  		err = pci_for_each_dma_alias(to_pci_dev(dev),
>  					     iort_pci_iommu_init, &info);
> 
> -		if (!err && iort_pci_rc_supports_ats(node))
> +		fwspec = dev_iommu_fwspec_get(dev);
> +		if (fwspec && iort_pci_rc_supports_ats(node))
>  			fwspec->flags |= IOMMU_FWSPEC_PCI_RC_ATS;
>  	} else {
>  		int i = 0;

Thanks a lot for the fix! I added it to patch 1/14.

Regards,

	Joerg