Re: [Xen-devel] [PATCH v2 1/4] iommu / x86: move call to scan_pci_devices() out of vendor code

["Woods, Brian" <Brian.Woods@xxxxxxx>]

On July 15, 2019 7:37:17 AM Paul Durrant <paul.durrant@xxxxxxxxxx> wrote:

> It's not vendor specific so it doesn't really belong there.
>
>
> Scanning the PCI topology also really doesn't have much to do with IOMMU
> initialization. It doesn't depend on there even being an IOMMU. This patch
> moves to the call to the beginning of iommu_hardware_setup() but only
> places it there because the topology information would be otherwise unused.
>
>
> Subsequent patches will actually make use of the PCI topology during
> (x86) IOMMU initialization.
>
>
> Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>

Acked-by: Brian Woods <brian.woods@xxxxxxx>

> ---
> Cc: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
> Cc: Brian Woods <brian.woods@xxxxxxx>
> Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
> Cc: Jan Beulich <jbeulich@xxxxxxxx>
> Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Cc: Wei Liu <wl@xxxxxxx>
> Cc: "Roger Pau Monné" <roger.pau@xxxxxxxxxx>
>
>
> v2:
> - Expanded commit comment.
> - Moved PCI scan to before IOMMU initialization, rather than after it.
> ---
> xen/drivers/passthrough/amd/pci_amd_iommu.c | 3 ++-
> xen/drivers/passthrough/vtd/iommu.c         | 4 ----
> xen/drivers/passthrough/x86/iommu.c         | 6 ++++++
> 3 files changed, 8 insertions(+), 5 deletions(-)
>
>
> diff --git a/xen/drivers/passthrough/amd/pci_amd_iommu.c 
> b/xen/drivers/passthrough/amd/pci_amd_iommu.c
> index 4afbcd1609..3338a8e0e8 100644
> --- a/xen/drivers/passthrough/amd/pci_amd_iommu.c
> +++ b/xen/drivers/passthrough/amd/pci_amd_iommu.c
> @@ -180,7 +180,8 @@ static int __init iov_detect(void)
>
>     if ( !amd_iommu_perdev_intremap )
>         printk(XENLOG_WARNING "AMD-Vi: Using global interrupt remap table is 
> not recommended (see XSA-36)!\n");
> -    return scan_pci_devices();
> +
> +    return 0;
> }
>
> int amd_iommu_alloc_root(struct domain_iommu *hd)
> diff --git a/xen/drivers/passthrough/vtd/iommu.c 
> b/xen/drivers/passthrough/vtd/iommu.c
> index 8b27d7e775..b0e3bf26b5 100644
> --- a/xen/drivers/passthrough/vtd/iommu.c
> +++ b/xen/drivers/passthrough/vtd/iommu.c
> @@ -2372,10 +2372,6 @@ static int __init vtd_setup(void)
>     P(iommu_hap_pt_share, "Shared EPT tables");
> #undef P
>
> -    ret = scan_pci_devices();
> -    if ( ret )
> -        goto error;
> -
>     ret = init_vtd_hw();
>     if ( ret )
>         goto error;
> diff --git a/xen/drivers/passthrough/x86/iommu.c 
> b/xen/drivers/passthrough/x86/iommu.c
> index 0fa6dcc3fd..a7438c9c25 100644
> --- a/xen/drivers/passthrough/x86/iommu.c
> +++ b/xen/drivers/passthrough/x86/iommu.c
> @@ -28,9 +28,15 @@ struct iommu_ops __read_mostly iommu_ops;
>
> int __init iommu_hardware_setup(void)
> {
> +    int rc;
> +
>     if ( !iommu_init_ops )
>         return -ENODEV;
>
> +    rc = scan_pci_devices();
> +    if ( rc )
> +        return rc;
> +
>     if ( !iommu_ops.init )
>         iommu_ops = *iommu_init_ops->ops;
>     else
> --
> 2.11.0


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