iommu/vt-d: Global PASID name space

This adds the system wide PASID name space for the PASID
allocation. Currently we are using per IOMMU PASID name
spaces which are not suitable for some use cases. For an
example, one application (associated with a PASID) might
talk to two physical devices simultaneously while the two
devices could reside behind two different IOMMU units.

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Liu Yi L <yi.l.liu@intel.com>
Suggested-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Liu Yi L <yi.l.liu@intel.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/Makefile

@@ -14,7 +14,7 @@ obj-$(CONFIG_AMD_IOMMU_V2) += amd_iommu_v2.o
 obj-$(CONFIG_ARM_SMMU) += arm-smmu.o
 obj-$(CONFIG_ARM_SMMU_V3) += arm-smmu-v3.o
 obj-$(CONFIG_DMAR_TABLE) += dmar.o
-obj-$(CONFIG_INTEL_IOMMU) += intel-iommu.o
+obj-$(CONFIG_INTEL_IOMMU) += intel-iommu.o intel-pasid.o
 obj-$(CONFIG_INTEL_IOMMU_SVM) += intel-svm.o
 obj-$(CONFIG_IPMMU_VMSA) += ipmmu-vmsa.o
 obj-$(CONFIG_IRQ_REMAP) += intel_irq_remapping.o irq_remapping.o

drivers/iommu/intel-iommu.c

@@ -53,6 +53,7 @@
 #include <asm/iommu.h>
 
 #include "irq_remapping.h"
+#include "intel-pasid.h"
 
 #define ROOT_SIZE		VTD_PAGE_SIZE
 #define CONTEXT_SIZE		VTD_PAGE_SIZE
@@ -3293,6 +3294,18 @@ static int __init init_dmars(void)
 	}
 
 	for_each_active_iommu(iommu, drhd) {
+		/*
+		 * Find the max pasid size of all IOMMU's in the system.
+		 * We need to ensure the system pasid table is no bigger
+		 * than the smallest supported.
+		 */
+		if (pasid_enabled(iommu)) {
+			u32 temp = 2 << ecap_pss(iommu->ecap);
+
+			intel_pasid_max_id = min_t(u32, temp,
+						   intel_pasid_max_id);
+		}
+
 		g_iommus[iommu->seq_id] = iommu;
 
 		intel_iommu_init_qi(iommu);

drivers/iommu/intel-pasid.c

@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0
+/**
+ * intel-pasid.c - PASID idr, table and entry manipulation
+ *
+ * Copyright (C) 2018 Intel Corporation
+ *
+ * Author: Lu Baolu <baolu.lu@linux.intel.com>
+ */
+
+#define pr_fmt(fmt)	"DMAR: " fmt
+
+#include <linux/dmar.h>
+#include <linux/intel-iommu.h>
+#include <linux/iommu.h>
+#include <linux/memory.h>
+#include <linux/spinlock.h>
+
+#include "intel-pasid.h"
+
+/*
+ * Intel IOMMU system wide PASID name space:
+ */
+static DEFINE_SPINLOCK(pasid_lock);
+u32 intel_pasid_max_id = PASID_MAX;
+static DEFINE_IDR(pasid_idr);
+
+int intel_pasid_alloc_id(void *ptr, int start, int end, gfp_t gfp)
+{
+	int ret, min, max;
+
+	min = max_t(int, start, PASID_MIN);
+	max = min_t(int, end, intel_pasid_max_id);
+
+	WARN_ON(in_interrupt());
+	idr_preload(gfp);
+	spin_lock(&pasid_lock);
+	ret = idr_alloc(&pasid_idr, ptr, min, max, GFP_ATOMIC);
+	spin_unlock(&pasid_lock);
+	idr_preload_end();
+
+	return ret;
+}
+
+void intel_pasid_free_id(int pasid)
+{
+	spin_lock(&pasid_lock);
+	idr_remove(&pasid_idr, pasid);
+	spin_unlock(&pasid_lock);
+}
+
+void *intel_pasid_lookup_id(int pasid)
+{
+	void *p;
+
+	spin_lock(&pasid_lock);
+	p = idr_find(&pasid_idr, pasid);
+	spin_unlock(&pasid_lock);
+
+	return p;
+}

drivers/iommu/intel-pasid.h

@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * intel-pasid.h - PASID idr, table and entry header
+ *
+ * Copyright (C) 2018 Intel Corporation
+ *
+ * Author: Lu Baolu <baolu.lu@linux.intel.com>
+ */
+
+#ifndef __INTEL_PASID_H
+#define __INTEL_PASID_H
+
+#define PASID_MIN			0x1
+#define PASID_MAX			0x100000
+
+extern u32 intel_pasid_max_id;
+int intel_pasid_alloc_id(void *ptr, int start, int end, gfp_t gfp);
+void intel_pasid_free_id(int pasid);
+void *intel_pasid_lookup_id(int pasid);
+
+#endif /* __INTEL_PASID_H */