[Intel-gfx] [PATCH 3/7] iommu/vt-d: Add intel_svm_{un, }bind_mm() functions
David Woodhouse
dwmw2 at infradead.org
Thu Oct 8 16:52:56 PDT 2015
This provides basic PASID support for endpoint devices, tested with a
version of the i915 driver.
A given process can bind to only one device per IOMMU for now. Making
that more generic isn't particularly difficult but isn't needed yet, and
can come later once the basic functionality is stable.
Eventually we'll also want the PASID space to be system-wide, not just
per-IOMMU. But when we have that requirement we'll also have a way to
achieve it.
Signed-off-by: David Woodhouse <David.Woodhouse at intel.com>
---
drivers/iommu/intel-iommu.c | 100 ++++++++++++++++++
drivers/iommu/intel-svm.c | 229 ++++++++++++++++++++++++++++++++++++++++++
include/linux/dma_remapping.h | 7 ++
include/linux/intel-iommu.h | 59 ++++++++++-
include/linux/intel-svm.h | 68 +++++++++++++
5 files changed, 458 insertions(+), 5 deletions(-)
create mode 100644 include/linux/intel-svm.h
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 1f89064..a6fd639 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4882,6 +4882,106 @@ static void intel_iommu_remove_device(struct device *dev)
iommu_device_unlink(iommu->iommu_dev, dev);
}
+#ifdef CONFIG_INTEL_IOMMU_SVM
+int intel_iommu_enable_pasid(struct intel_svm *svm)
+{
+ struct device_domain_info *info = NULL;
+ struct context_entry *context;
+ struct dmar_domain *domain;
+ unsigned long flags;
+ u8 bus, devfn;
+ u64 ctx_lo;
+
+ if (iommu_dummy(svm->dev)) {
+ dev_warn(svm->dev,
+ "No IOMMU translation for device; cannot enable SVM\n");
+ return -EINVAL;
+ }
+
+ domain = get_valid_domain_for_dev(svm->dev);
+ if (!domain) {
+ dev_warn(svm->dev, "Cannot get IOMMU domain to enable SVM\n");
+ return -EINVAL;
+ }
+
+ svm->iommu = device_to_iommu(svm->dev, &bus, &devfn);
+ if (!ecs_enabled(svm->iommu)) {
+ dev_dbg(svm->dev, "No ECS support on IOMMU; cannot enable SVM\n");
+ return -EINVAL;
+ }
+ svm->did = domain->iommu_did[svm->iommu->seq_id];
+
+ spin_lock_irqsave(&device_domain_lock, flags);
+ spin_lock(&svm->iommu->lock);
+ context = iommu_context_addr(svm->iommu, bus, devfn, 0);
+ if (WARN_ON(!context)) {
+ spin_unlock(&svm->iommu->lock);
+ spin_unlock_irqrestore(&device_domain_lock, flags);
+ return -EINVAL;
+ }
+
+ ctx_lo = context[0].lo;
+ /* Modes in which the device IOTLB is enabled are 1 and 5. Modes
+ * 3 and 7 are invalid. so we only need to test the low bit of TT */
+ svm->dev_iotlb = (ctx_lo >> 2) & 1;
+
+ if (!(ctx_lo & CONTEXT_PASIDE)) {
+ context[1].hi = (u64)virt_to_phys(svm->iommu->pasid_state_table);
+ context[1].lo = (u64)virt_to_phys(svm->iommu->pasid_table) | ecap_pss(svm->iommu->ecap);
+ wmb();
+ /* CONTEXT_TT_MULTI_LEVEL and CONTEXT_TT_DEV_IOTLB are both
+ * extended to permit requests-with-PASID if the PASIDE bit
+ * is set. which makes sense. For CONTEXT_TT_PASS_THROUGH,
+ * however, the PASIDE bit is ignored and requests-with-PASID
+ * are unconditionally blocked. Which makes less sense.
+ * So convert from CONTEXT_TT_PASS_THROUGH to one of the new
+ * "guest mode" translation types depending on whether ATS
+ * is available or not. */
+ if ((ctx_lo & CONTEXT_TT_MASK) == (CONTEXT_TT_PASS_THROUGH << 2)) {
+ ctx_lo &= ~CONTEXT_TT_MASK;
+ info = iommu_support_dev_iotlb(domain, svm->iommu, bus, devfn);
+ if (info) {
+ ctx_lo |= CONTEXT_TT_PT_PASID_DEV_IOTLB << 2;
+ svm->dev_iotlb = 1;
+ } else
+ ctx_lo |= CONTEXT_TT_PT_PASID << 2;
+ }
+ ctx_lo |= CONTEXT_PASIDE;
+ context[0].lo = ctx_lo;
+ wmb();
+ svm->iommu->flush.flush_context(svm->iommu, svm->did,
+ (((u16)bus) << 8) | devfn,
+ DMA_CCMD_MASK_NOBIT,
+ DMA_CCMD_DEVICE_INVL);
+ }
+ spin_unlock(&svm->iommu->lock);
+ spin_unlock_irqrestore(&device_domain_lock, flags);
+
+ /* This only happens if we just switched from CONTEXT_TT_PASS_THROUGH */
+ if (info)
+ iommu_enable_dev_iotlb(info);
+
+ /* This can also happen when we were already in a dev-iotlb mode */
+ if (svm->dev_iotlb) {
+ svm->qdep = pci_ats_queue_depth(to_pci_dev(svm->dev));
+ if (svm->qdep >= QI_DEV_EIOTLB_MAX_INVS)
+ svm->qdep = 0;
+ svm->sid = (((u16)bus) << 8) | devfn;
+ }
+
+ return 0;
+}
+
+/* Helper function for SVM code, so that we can look up a given PASID
+ * in its IOMMU's pasid_idr for unbinding */
+struct intel_iommu *intel_iommu_device_to_iommu(struct device *dev)
+{
+ u8 bus, devfn;
+
+ return device_to_iommu(dev, &bus, &devfn);
+}
+#endif /* CONFIG_INTEL_IOMMU_SVM */
+
static const struct iommu_ops intel_iommu_ops = {
.capable = intel_iommu_capable,
.domain_alloc = intel_iommu_domain_alloc,
diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 9b40ad6..913c3a1 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -14,6 +14,14 @@
*/
#include <linux/intel-iommu.h>
+#include <linux/mmu_notifier.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/intel-svm.h>
+
+struct pasid_entry {
+ u64 val;
+};
int intel_svm_alloc_pasid_tables(struct intel_iommu *iommu)
{
@@ -40,6 +48,8 @@ int intel_svm_alloc_pasid_tables(struct intel_iommu *iommu)
return -ENOMEM;
}
iommu->pasid_state_table = page_address(pages);
+ idr_init(&iommu->pasid_idr);
+
pr_info("%s: Allocated order %d PASID table.\n", iommu->name, order);
return 0;
@@ -61,5 +71,224 @@ int intel_svm_free_pasid_tables(struct intel_iommu *iommu)
free_pages((unsigned long)iommu->pasid_state_table, order);
iommu->pasid_state_table = NULL;
}
+ idr_destroy(&iommu->pasid_idr);
return 0;
}
+
+static void intel_flush_svm_range(struct intel_svm *svm,
+ unsigned long address, int pages, int ih)
+{
+ struct qi_desc desc;
+ int mask = ilog2(__roundup_pow_of_two(pages));
+
+ if (pages == -1 || !cap_pgsel_inv(svm->iommu->cap) ||
+ mask > cap_max_amask_val(svm->iommu->cap)) {
+ desc.low = QI_EIOTLB_PASID(svm->pasid) | QI_EIOTLB_DID(svm->did) |
+ QI_EIOTLB_GRAN(QI_GRAN_NONG_PASID) | QI_EIOTLB_TYPE;
+ desc.high = 0;
+ } else {
+ desc.low = QI_EIOTLB_PASID(svm->pasid) | QI_EIOTLB_DID(svm->did) |
+ QI_EIOTLB_GRAN(QI_GRAN_PSI_PASID) | QI_EIOTLB_TYPE;
+ desc.high = QI_EIOTLB_ADDR(address) | QI_EIOTLB_GL(1) |
+ QI_EIOTLB_IH(ih) | QI_EIOTLB_AM(mask);
+ }
+
+ qi_submit_sync(&desc, svm->iommu);
+
+ if (svm->dev_iotlb) {
+ desc.low = QI_DEV_EIOTLB_PASID(svm->pasid) | QI_DEV_EIOTLB_SID(svm->sid) |
+ QI_DEV_EIOTLB_QDEP(svm->qdep) | QI_DEIOTLB_TYPE;
+ if (mask) {
+ unsigned long adr, delta;
+
+ /* Least significant zero bits in the address indicate the
+ * range of the request. So mask them out according to the
+ * size. */
+ adr = address & ((1<<(VTD_PAGE_SHIFT + mask)) - 1);
+
+ /* Now ensure that we round down further if the original
+ * request was not aligned w.r.t. its size */
+ delta = address - adr;
+ if (delta + (pages << VTD_PAGE_SHIFT) >= (1 << (VTD_PAGE_SHIFT + mask)))
+ adr &= ~(1 << (VTD_PAGE_SHIFT + mask));
+ desc.high = QI_DEV_EIOTLB_ADDR(adr) | QI_DEV_EIOTLB_SIZE;
+ } else {
+ desc.high = QI_DEV_EIOTLB_ADDR(address);
+ }
+ qi_submit_sync(&desc, svm->iommu);
+ }
+}
+
+
+static void intel_change_pte(struct mmu_notifier *mn, struct mm_struct *mm,
+ unsigned long address, pte_t pte)
+{
+ struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
+
+ intel_flush_svm_range(svm, address, 1, 1);
+}
+
+static void intel_invalidate_page(struct mmu_notifier *mn, struct mm_struct *mm,
+ unsigned long address)
+{
+ struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
+
+ intel_flush_svm_range(svm, address, 1, 1);
+}
+
+/* Pages have been freed at this point */
+static void intel_invalidate_range_end(struct mmu_notifier *mn,
+ struct mm_struct *mm,
+ unsigned long start, unsigned long end)
+{
+ struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
+
+ intel_flush_svm_range(svm, start,
+ (end - start + PAGE_SIZE - 1) >> VTD_PAGE_SHIFT , 0);
+}
+
+static void intel_flush_pasid(struct intel_svm *svm)
+{
+ struct qi_desc desc;
+
+ desc.high = 0;
+ desc.low = QI_PC_TYPE | QI_PC_DID(svm->did) | QI_PC_PASID_SEL | QI_PC_PASID(svm->pasid);
+
+ qi_submit_sync(&desc, svm->iommu);
+}
+
+static void intel_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
+{
+ struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
+
+ /* Called either when the process exits, or on the last unbind */
+ svm->iommu->pasid_table[svm->pasid].val = 0;
+
+ intel_flush_pasid(svm);
+ intel_flush_svm_range(svm, 0, -1, 0);
+
+ /* XXX: Callback to device driver to let it know? */
+}
+
+static const struct mmu_notifier_ops intel_mmuops = {
+ .release = intel_mm_release,
+ .change_pte = intel_change_pte,
+ .invalidate_page = intel_invalidate_page,
+ .invalidate_range_end = intel_invalidate_range_end,
+};
+
+static DEFINE_MUTEX(pasid_mutex);
+
+int intel_svm_bind_mm(struct device *dev, int *pasid)
+{
+ struct intel_svm *svm;
+ int pasid_max;
+ int ret;
+
+ BUG_ON(pasid && !current->mm);
+
+ mutex_lock(&pasid_mutex);
+ if (pasid) {
+ struct intel_iommu *iommu = intel_iommu_device_to_iommu(dev);
+ int pasid;
+
+ if (!iommu || !iommu->pasid_table) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ idr_for_each_entry(&iommu->pasid_idr, svm, pasid) {
+ if (svm->mm != current->mm)
+ continue;
+
+ if (dev != svm->dev) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ kref_get(&svm->kref);
+ goto success;
+ }
+ }
+
+ svm = kzalloc(sizeof(*svm), GFP_KERNEL);
+ if (!svm) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ kref_init(&svm->kref);
+ svm->dev = dev;
+ ret = intel_iommu_enable_pasid(svm);
+ if (ret) {
+ kfree(svm);
+ goto out;
+ }
+ if (!pasid) {
+ /* If they don't actually want to assign a PASID, this is
+ * just an enabling check/preparation. */
+ kfree(svm);
+ goto out;
+ }
+
+ pasid_max = 2 << ecap_pss(svm->iommu->ecap);
+ /* FIXME: Factor in device max too. */
+ ret = idr_alloc(&svm->iommu->pasid_idr, svm, 0, pasid_max - 1,
+ GFP_KERNEL);
+ if (ret < 0) {
+ kfree(svm);
+ goto out;
+ }
+ svm->pasid = ret;
+ svm->notifier.ops = &intel_mmuops;
+ svm->mm = get_task_mm(current);
+ ret = -ENOMEM;
+ if (!svm->mm || (ret = mmu_notifier_register(&svm->notifier, svm->mm))) {
+ idr_remove(&svm->iommu->pasid_idr, svm->pasid);
+ kfree(svm);
+ goto out;
+ }
+ svm->iommu->pasid_table[svm->pasid].val = (u64)__pa(current->mm->pgd) | 1;
+
+ success:
+ *pasid = svm->pasid;
+ ret = 0;
+ out:
+ mutex_unlock(&pasid_mutex);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(intel_svm_bind_mm);
+
+static void intel_mm_free(struct kref *svm_ref)
+{
+ struct intel_svm *svm = container_of(svm_ref, struct intel_svm, kref);
+
+ mmu_notifier_unregister(&svm->notifier, svm->mm);
+
+ idr_remove(&svm->iommu->pasid_idr, svm->pasid);
+ mmput(svm->mm);
+ kfree(svm);
+}
+
+int intel_svm_unbind_mm(struct device *dev, int pasid)
+{
+ struct intel_svm *svm;
+ struct intel_iommu *iommu;
+ int ret = -EINVAL;
+
+ mutex_lock(&pasid_mutex);
+ iommu = intel_iommu_device_to_iommu(dev);
+ if (!iommu || !iommu->pasid_table)
+ goto out;
+
+ svm = idr_find(&iommu->pasid_idr, pasid);
+ if (!svm)
+ goto out;
+
+ kref_put(&svm->kref, intel_mm_free);
+ ret = 0;
+ out:
+ mutex_unlock(&pasid_mutex);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(intel_svm_unbind_mm);
diff --git a/include/linux/dma_remapping.h b/include/linux/dma_remapping.h
index 7ac17f5..0e114bf 100644
--- a/include/linux/dma_remapping.h
+++ b/include/linux/dma_remapping.h
@@ -20,6 +20,13 @@
#define CONTEXT_TT_MULTI_LEVEL 0
#define CONTEXT_TT_DEV_IOTLB 1
#define CONTEXT_TT_PASS_THROUGH 2
+/* Extended context entry types */
+#define CONTEXT_TT_PT_PASID 4
+#define CONTEXT_TT_PT_PASID_DEV_IOTLB 5
+#define CONTEXT_TT_MASK (7ULL << 2)
+
+#define CONTEXT_PRS (1ULL << 9)
+#define CONTEXT_PASIDE (1ULL << 11)
struct intel_iommu;
struct dmar_domain;
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index 47844cb..b0df572 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -1,5 +1,9 @@
/*
- * Copyright (c) 2006, Intel Corporation.
+ * Copyright © 2006-2015, Intel Corporation.
+ *
+ * Authors: Ashok Raj <ashok.raj at intel.com>
+ * Anil S Keshavamurthy <anil.s.keshavamurthy at intel.com>
+ * David Woodhouse <David.Woodhouse at intel.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
@@ -13,10 +17,6 @@
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
* Place - Suite 330, Boston, MA 02111-1307 USA.
- *
- * Copyright (C) 2006-2008 Intel Corporation
- * Author: Ashok Raj <ashok.raj at intel.com>
- * Author: Anil S Keshavamurthy <anil.s.keshavamurthy at intel.com>
*/
#ifndef _INTEL_IOMMU_H_
@@ -25,7 +25,9 @@
#include <linux/types.h>
#include <linux/iova.h>
#include <linux/io.h>
+#include <linux/idr.h>
#include <linux/dma_remapping.h>
+#include <linux/mmu_notifier.h>
#include <asm/cacheflush.h>
#include <asm/iommu.h>
@@ -253,6 +255,9 @@ enum {
#define QI_DIOTLB_TYPE 0x3
#define QI_IEC_TYPE 0x4
#define QI_IWD_TYPE 0x5
+#define QI_EIOTLB_TYPE 0x6
+#define QI_PC_TYPE 0x7
+#define QI_DEIOTLB_TYPE 0x8
#define QI_IEC_SELECTIVE (((u64)1) << 4)
#define QI_IEC_IIDEX(idx) (((u64)(idx & 0xffff) << 32))
@@ -280,6 +285,34 @@ enum {
#define QI_DEV_IOTLB_SIZE 1
#define QI_DEV_IOTLB_MAX_INVS 32
+#define QI_PC_PASID(pasid) (((u64)pasid) << 32)
+#define QI_PC_DID(did) (((u64)did) << 16)
+#define QI_PC_GRAN(gran) (((u64)gran) << 4)
+
+#define QI_PC_ALL_PASIDS (QI_PC_TYPE | QI_PC_GRAN(0))
+#define QI_PC_PASID_SEL (QI_PC_TYPE | QI_PC_GRAN(1))
+
+#define QI_EIOTLB_ADDR(addr) ((u64)(addr) & VTD_PAGE_MASK)
+#define QI_EIOTLB_GL(gl) (((u64)gl) << 7)
+#define QI_EIOTLB_IH(ih) (((u64)ih) << 6)
+#define QI_EIOTLB_AM(am) (((u64)am))
+#define QI_EIOTLB_PASID(pasid) (((u64)pasid) << 32)
+#define QI_EIOTLB_DID(did) (((u64)did) << 16)
+#define QI_EIOTLB_GRAN(gran) (((u64)gran) << 4)
+
+#define QI_DEV_EIOTLB_ADDR(a) ((u64)(a) & VTD_PAGE_MASK)
+#define QI_DEV_EIOTLB_SIZE (((u64)1) << 11)
+#define QI_DEV_EIOTLB_GLOB(g) ((u64)g)
+#define QI_DEV_EIOTLB_PASID(p) (((u64)p) << 32)
+#define QI_DEV_EIOTLB_SID(sid) ((u64)((sid) & 0xffff) << 32)
+#define QI_DEV_EIOTLB_QDEP(qd) (((qd) & 0x1f) << 16)
+#define QI_DEV_EIOTLB_MAX_INVS 32
+
+#define QI_GRAN_ALL_ALL 0
+#define QI_GRAN_NONG_ALL 1
+#define QI_GRAN_NONG_PASID 2
+#define QI_GRAN_PSI_PASID 3
+
struct qi_desc {
u64 low, high;
};
@@ -361,6 +394,7 @@ struct intel_iommu {
* told to. But while it's all driver-arbitrated, we're fine. */
struct pasid_entry *pasid_table;
struct pasid_state_entry *pasid_state_table;
+ struct idr pasid_idr;
#endif
struct q_inval *qi; /* Queued invalidation info */
u32 *iommu_state; /* Store iommu states between suspend and resume.*/
@@ -404,6 +438,21 @@ extern int dmar_ir_support(void);
extern int intel_svm_alloc_pasid_tables(struct intel_iommu *iommu);
extern int intel_svm_free_pasid_tables(struct intel_iommu *iommu);
+struct intel_svm {
+ struct kref kref;
+ struct mmu_notifier notifier;
+ struct mm_struct *mm;
+ struct intel_iommu *iommu;
+ struct device *dev;
+ int pasid;
+ u16 did;
+ u16 dev_iotlb:1;
+ u16 sid, qdep;
+};
+
+extern int intel_iommu_enable_pasid(struct intel_svm *svm);
+extern struct intel_iommu *intel_iommu_device_to_iommu(struct device *dev);
+
extern const struct attribute_group *intel_iommu_groups[];
#endif
diff --git a/include/linux/intel-svm.h b/include/linux/intel-svm.h
new file mode 100644
index 0000000..1e84f3e
--- /dev/null
+++ b/include/linux/intel-svm.h
@@ -0,0 +1,68 @@
+/*
+ * Copyright © 2015 Intel Corporation.
+ *
+ * Authors: David Woodhouse <David.Woodhouse at intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+
+#ifndef __INTEL_SVM_H__
+#define __INTEL_SVM_H__
+
+struct device;
+
+/**
+ * intel_svm_bind_mm() - Bind the current process to a PASID
+ * @dev: Device to be granted acccess
+ * @pasid: Address for allocated PASID
+ *
+ * This function attempts to enable PASID support for the given device.
+ * If the @pasid argument is non-%NULL, a PASID is allocated for access
+ * to the MM of the current process.
+ *
+ * By using a %NULL value for the @pasid argument, this function can
+ * be used to simply validate that PASID support is available for the
+ * given device — i.e. that it is behind an IOMMU which has the
+ * requisite support, and is enabled.
+ *
+ * Page faults are handled transparently by the IOMMU code, and there
+ * should be no need for the device driver to be involved. If a page
+ * fault cannot be handled (i.e. is an invalid address rather than
+ * just needs paging in), then the page request will be completed by
+ * the core IOMMU code with appropriate status, and the device itself
+ * can then report the resulting fault to its driver via whatever
+ * mechanism is appropriate.
+ *
+ * Multiple calls from the same process may result in the same PASID
+ * being re-used. A reference count is kept.
+ */
+extern int intel_svm_bind_mm(struct device *dev, int *pasid);
+
+#define intel_svm_available(dev) intel_svm_bind_mm((dev), NULL)
+
+/**
+ * intel_svm_unbind_mm() - Unbind a specified PASID
+ * @dev: Device for which PASID was allocated
+ * @pasid: PASID value to be unbound
+ *
+ * This function allows a PASID to be retired when the device no
+ * longer requires access to the address space of a given process.
+ *
+ * If the use count for the PASID in question reaches zero, the
+ * PASID is revoked and may no longer be used by hardware.
+ *
+ * Device drivers are required to ensure that no access (including
+ * page requests) is currently outstanding for the PASID in question,
+ * before calling this function.
+ */
+extern int intel_svm_unbind_mm(struct device *dev, int pasid);
+
+
+#endif /* __INTEL_SVM_H__ */
--
2.4.3
--
David Woodhouse Open Source Technology Centre
David.Woodhouse at intel.com Intel Corporation
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