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Commit 65ca7f5f authored by Jacob Pan's avatar Jacob Pan Committed by Joerg Roedel
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iommu/vt-d: Fix pasid table size encoding 



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.kuoppala@linux.intel.com>
cc: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: default avatarJacob Pan <jacob.jun.pan@linux.intel.com>
Tested-by: default avatarMika Kuoppala <mika.kuoppala@intel.com>
Fixes: 2f26e0a9 ('iommu/vt-d: Add basic SVM PASID support')
Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent aec0e861

drivers/iommu/intel-iommu.c

+22 −1
Original line number Diff line number Diff line
@@ -5204,6 +5204,25 @@ 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;
@@ -5236,7 +5255,9 @@ 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