Re: [PATCH v3] Prevent devices with RMRRs from being placed into SIDomain during startup

From: Alex Williamson
Date: Tue Oct 16 2012 - 12:59:42 EST


On Tue, 2012-10-16 at 16:50 +0000, Tom Mingarelli wrote:
> This patch is to prevent devices that have RMRRs associated with them
> from getting placed into the SI Domain during init. We don't put USB devices
> into this category, however. This fixes the issue where the RMRR info
> for devices being placed in and out of the SI Domain gets lost.
>
> Signed-off-by: Thomas Mingarelli <thomas.mingarelli@xxxxxx>
> ----
> PATCH v1: https://lkml.org/lkml/2012/6/15/204
> PATCH v2: https://lkml.org/lkml/2012/9/18/354
>
> drivers/iommu/intel-iommu.c | 33 +++++++++++++++++++++++++++++++++
> 1 files changed, 33 insertions(+), 0 deletions(-)
>
> diff -up ./drivers/iommu/intel-iommu.c.ORIG ./drivers/iommu/intel-iommu.c
> --- ./drivers/iommu/intel-iommu.c.ORIG 2012-10-16 09:34:23.148089944 -0500
> +++ ./drivers/iommu/intel-iommu.c 2012-10-16 09:56:56.905932861 -0500
> @@ -2320,8 +2320,41 @@ static int domain_add_dev_info(struct dm
> return 0;
> }
>
> +static bool device_has_rmrr(struct pci_dev *dev)
> +{
> + struct dmar_rmrr_unit *rmrr;
> + int i;
> +
> + for_each_rmrr_units(rmrr) {
> + for (i = 0; i < rmrr->devices_cnt; i++) {
> + /*
> + * Here we are just concerned with checking each device
> + * that has an RMRR associated with it and not allow it
> + * to be placed into the SI Domain during startup.
> + */
> + if (rmrr->devices[i] == dev)
> + return true;
> + }
> + }
> + return false;
> +}
> +
> static int iommu_should_identity_map(struct pci_dev *pdev, int startup)
> {
> +
> + if (startup) {
> + /*
> + * This is where we will refuse any device that has an
> + * RMRR associated with it and is not a USB device and
> + * NOT allow it to be placed into the SI Domain. We
> + * only do this on startup.

Why only on startup?

> We don't need a separate bit
> + * for this because it could be ANY device.
> + */

Note the white space here doesn't match existing comment blocks in
intel-iommu.

> + if (device_has_rmrr(pdev) &&
> + (pdev->class >> 8) != PCI_CLASS_SERIAL_USB)
> + return 0;
> + }
> +
> if ((iommu_identity_mapping & IDENTMAP_AZALIA) && IS_AZALIA(pdev))
> return 1;
>

Thanks,
Alex

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