Re: [PATCH v4 4/7] iommu/vt-d: Handle non-page aligned address

Jacob Pan
2020-07-21T16:43:57Z

Hi Baolu,

Not sure what state is this patch in, there is a bug in this patch
(see below), shall I send out an updated version of this one only? or
another incremental patch.

Thanks,

Jacob

On Mon, 6 Jul 2020 17:12:51 -0700
Jacob Pan <jacob.jun.pan@linux.intel.com> wrote:

> From: Liu Yi L <yi.l.liu@intel.com>
>
> Address information for device TLB invalidation comes from userspace
> when device is directly assigned to a guest with vIOMMU support.
> VT-d requires page aligned address. This patch checks and enforce
> address to be page aligned, otherwise reserved bits can be set in the
> invalidation descriptor. Unrecoverable fault will be reported due to
> non-zero value in the reserved bits.
>
> Fixes: 61a06a16e36d8 ("iommu/vt-d: Support flushing more translation
> cache types")
> Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
> Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
>
> ---
> drivers/iommu/intel/dmar.c | 20 ++++++++++++++++++--
> 1 file changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c
> index d9f973fa1190..b2c53bada905 100644
> --- a/drivers/iommu/intel/dmar.c
> +++ b/drivers/iommu/intel/dmar.c
> @@ -1455,9 +1455,25 @@ void qi_flush_dev_iotlb_pasid(struct
> intel_iommu *iommu, u16 sid, u16 pfsid,
> * Max Invs Pending (MIP) is set to 0 for now until we have
> DIT in
> * ECAP.
> */
> - desc.qw1 |= addr & ~mask;
> - if (size_order)
> + if (addr & GENMASK_ULL(size_order + VTD_PAGE_SHIFT, 0))
> + pr_warn_ratelimited("Invalidate non-aligned address
> %llx, order %d\n", addr, size_order); +
> + /* Take page address */
> + desc.qw1 = QI_DEV_EIOTLB_ADDR(addr);
> +
> + if (size_order) {
> + /*
> + * Existing 0s in address below size_order may be
> the least
> + * significant bit, we must set them to 1s to avoid
> having
> + * smaller size than desired.
> + */
> + desc.qw1 |= GENMASK_ULL(size_order + VTD_PAGE_SHIFT,
> + VTD_PAGE_SHIFT);
Yi reported the issue, it should be:
desc.qw1 |= GENMASK_ULL(size_order + VTD_PAGE_SHIFT - 1,
VTD_PAGE_SHIFT);

> + /* Clear size_order bit to indicate size */
> + desc.qw1 &= ~mask;
> + /* Set the S bit to indicate flushing more than 1
> page */ desc.qw1 |= QI_DEV_EIOTLB_SIZE;
> + }
>
> qi_submit_sync(iommu, &desc, 1, 0);
> }

[Jacob Pan]