Jacob Pan <jacob.jun....@linux.intel.com> writes:
> Different encodings are used to represent supported PASID bits
> and number of PASID table entries.
> The current code assigns ecap_pss directly to extended context
> table entry PTS which is wrong and could result in writing
> non-zero bits to the reserved fields. IOMMU fault reason
> 11 will be reported when reserved bits are nonzero.
> This patch converts ecap_pss to extend context entry pts encoding
> based on VT-d spec. Chapter 9.4 as follows:
> - number of PASID bits = ecap_pss + 1
> - number of PASID table entries = 2^(pts + 5)
> Software assigned limit of pasid_max value is also respected to
> match the allocation limitation of PASID table.
>
> cc: Mika Kuoppala <mika.kuopp...@linux.intel.com>
> cc: Ashok Raj <ashok....@intel.com>
> Signed-off-by: Jacob Pan <jacob.jun....@linux.intel.com>
Tested-by: Mika Kuoppala <mika.kuopp...@intel.com>
> ---
> drivers/iommu/intel-iommu.c | 23 ++++++++++++++++++++++-
> 1 file changed, 22 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 27596e6..5d9cddc 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -5173,6 +5173,25 @@ static void intel_iommu_remove_device(struct device
> *dev)
> }
>
> #ifdef CONFIG_INTEL_IOMMU_SVM
> +#define MAX_NR_PASID_BITS (20)
> +static inline unsigned long intel_iommu_get_pts(struct intel_iommu *iommu)
> +{
> + /*
> + * Convert ecap_pss to extend context entry pts encoding, also
> + * respect the soft pasid_max value set by the iommu.
> + * - number of PASID bits = ecap_pss + 1
> + * - number of PASID table entries = 2^(pts + 5)
> + * Therefore, pts = ecap_pss - 4
> + * e.g. KBL ecap_pss = 0x13, PASID has 20 bits, pts = 15
> + */
> + if (ecap_pss(iommu->ecap) < 5)
> + return 0;
> +
> + /* pasid_max is encoded as actual number of entries not the bits */
> + return find_first_bit((unsigned long *)&iommu->pasid_max,
> + MAX_NR_PASID_BITS) - 5;
> +}
> +
> int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct intel_svm_dev
> *sdev)
> {
> struct device_domain_info *info;
> @@ -5205,7 +5224,9 @@ int intel_iommu_enable_pasid(struct intel_iommu *iommu,
> struct intel_svm_dev *sd
>
> if (!(ctx_lo & CONTEXT_PASIDE)) {
> context[1].hi = (u64)virt_to_phys(iommu->pasid_state_table);
> - context[1].lo = (u64)virt_to_phys(iommu->pasid_table) |
> ecap_pss(iommu->ecap);
> + context[1].lo = (u64)virt_to_phys(iommu->pasid_table) |
> + intel_iommu_get_pts(iommu);
> +
> wmb();
> /* CONTEXT_TT_MULTI_LEVEL and CONTEXT_TT_DEV_IOTLB are both
> * extended to permit requests-with-PASID if the PASIDE bit
> --
> 2.7.4
