// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright © 2015 Intel Corporation.
*
* Authors: David Woodhouse <dwmw2@infradead.org>
*/
#include <linux/intel-iommu.h>
#include <linux/mmu_notifier.h>
#include <linux/sched.h>
#include <linux/sched/mm.h>
#include <linux/slab.h>
#include <linux/intel-svm.h>
#include <linux/rculist.h>
#include <linux/pci.h>
#include <linux/pci-ats.h>
#include <linux/dmar.h>
#include <linux/interrupt.h>
#include <linux/mm_types.h>
#include <asm/page.h>
#include "intel-pasid.h"
static irqreturn_t prq_event_thread(int irq, void *d);
int intel_svm_init(struct intel_iommu *iommu)
{
if (cpu_feature_enabled(X86_FEATURE_GBPAGES) &&
!cap_fl1gp_support(iommu->cap))
return -EINVAL;
if (cpu_feature_enabled(X86_FEATURE_LA57) &&
!cap_5lp_support(iommu->cap))
return -EINVAL;
return 0;
}
#define PRQ_ORDER 0
int intel_svm_enable_prq(struct intel_iommu *iommu)
{
struct page *pages;
int irq, ret;
pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, PRQ_ORDER);
if (!pages) {
pr_warn("IOMMU: %s: Failed to allocate page request queue\n",
iommu->name);
return -ENOMEM;
}
iommu->prq = page_address(pages);
irq = dmar_alloc_hwirq(DMAR_UNITS_SUPPORTED + iommu->seq_id, iommu->node, iommu);
if (irq <= 0) {
pr_err("IOMMU: %s: Failed to create IRQ vector for page request queue\n",
iommu->name);
ret = -EINVAL;
err:
free_pages((unsigned long)iommu->prq, PRQ_ORDER);
iommu->prq = NULL;
return ret;
}
iommu->pr_irq = irq;
snprintf(iommu->prq_name, sizeof(iommu->prq_name), "dmar%d-prq", iommu->seq_id);
ret = request_threaded_irq(irq, NULL, prq_event_thread, IRQF_ONESHOT,
iommu->prq_name, iommu);
if (ret) {
pr_err("IOMMU: %s: Failed to request IRQ for page request queue\n",
iommu->name);
dmar_free_hwirq(irq);
iommu->pr_irq = 0;
goto err;
}
dmar_writeq(iommu->reg + DMAR_PQH_REG, 0ULL);
dmar_writeq(iommu->reg + DMAR_PQT_REG, 0ULL);
dmar_writeq(iommu->reg + DMAR_PQA_REG, virt_to_phys(iommu->prq) | PRQ_ORDER);
return 0;
}
int intel_svm_finish_prq(struct intel_iommu *iommu)
{
dmar_writeq(iommu->reg + DMAR_PQH_REG, 0ULL);
dmar_writeq(iommu->reg + DMAR_PQT_REG, 0ULL);
dmar_writeq(iommu->reg + DMAR_PQA_REG, 0ULL);
if (iommu->pr_irq) {
free_irq(iommu->pr_irq, iommu);
dmar_free_hwirq(iommu->pr_irq);
iommu->pr_irq = 0;
}
free_pages((unsigned long)iommu->prq, PRQ_ORDER);
iommu->prq = NULL;
return 0;
}
static void intel_flush_svm_range_dev (struct intel_svm *svm, struct intel_svm_dev *sdev,
unsigned long address, unsigned long pages, int ih, int gl)
{
struct qi_desc desc;
if (pages == -1) {
/* For global kernel pages we have to flush them in *all* PASIDs
* because that's the only option the hardware gives us. Despite
* the fact that they are actually only accessible through one. */
if (gl)
desc.qw0 = QI_EIOTLB_PASID(svm->pasid) |
QI_EIOTLB_DID(sdev->did) |
QI_EIOTLB_GRAN(QI_GRAN_ALL_ALL) |
QI_EIOTLB_TYPE;
else
desc.qw0 = QI_EIOTLB_PASID(svm->pasid) |
QI_EIOTLB_DID(sdev->did) |
QI_EIOTLB_GRAN(QI_GRAN_NONG_PASID) |
QI_EIOTLB_TYPE;
desc.qw1 = 0;
} else {
int mask = ilog2(__roundup_pow_of_two(pages));
desc.qw0 = QI_EIOTLB_PASID(svm->pasid) |
QI_EIOTLB_DID(sdev->did) |
QI_EIOTLB_GRAN(QI_GRAN_PSI_PASID) |
QI_EIOTLB_TYPE;
desc.qw1 = QI_EIOTLB_ADDR(address) |
QI_EIOTLB_GL(gl) |
QI_EIOTLB_IH(ih) |
QI_EIOTLB_AM(mask);
}
desc.qw2 = 0;
desc.qw3 = 0;
qi_submit_sync(&desc, svm->iommu);
if (sdev->dev_iotlb) {
desc.qw0 = QI_DEV_EIOTLB_PASID(svm->pasid) |
QI_DEV_EIOTLB_SID(sdev->sid) |
QI_DEV_EIOTLB_QDEP(sdev->qdep) |
QI_DEIOTLB_TYPE;
if (pages == -1) {
desc.qw1 = QI_DEV_EIOTLB_ADDR(-1ULL >> 1) |
QI_DEV_EIOTLB_SIZE;
} else if (pages > 1) {
/* The least significant zero bit indicates the size. So,
* for example, an "address" value of 0x12345f000 will
* flush from 0x123440000 to 0x12347ffff (256KiB). */
unsigned long last = address + ((unsigned long)(pages - 1) << VTD_PAGE_SHIFT);
unsigned long mask = __rounddown_pow_of_two(address ^ last);
desc.qw1 = QI_DEV_EIOTLB_ADDR((address & ~mask) |
(mask - 1)) | QI_DEV_EIOTLB_SIZE;
} else {
desc.qw1 = QI_DEV_EIOTLB_ADDR(address);
}
desc.qw2 = 0;
desc.qw3 = 0;
qi_submit_sync(&desc, svm->iommu);
}
}
static void intel_flush_svm_range(struct intel_svm *svm, unsigned long address,
unsigned long pages, int ih, int gl)
{
struct intel_svm_dev *sdev;
rcu_read_lock();
list_for_each_entry_rcu(sdev, &svm->devs, list)
intel_flush_svm_range_dev(svm, sdev, address, pages, ih, gl);
rcu_read_unlock();
}
/* Pages have been freed at this point */
static void intel_invalidate_range(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, 0);
}
static void intel_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
{
struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
struct intel_svm_dev *sdev;
/* This might end up being called from exit_mmap(), *before* the page
* tables are cleared. And __mmu_notifier_release() will delete us from
* the list of notifiers so that our invalidate_range() callback doesn't
* get called when the page tables are cleared. So we need to protect
* against hardware accessing those page tables.
*
* We do it by clearing the entry in the PASID table and then flushing
* the IOTLB and the PASID table caches. This might upset hardware;
* perhaps we'll want to point the PASID to a dummy PGD (like the zero
* page) so that we end up taking a fault that the hardware really
* *has* to handle gracefully without affecting other processes.
*/
rcu_read_lock();
list_for_each_entry_rcu(sdev, &svm->devs, list) {
intel_pasid_tear_down_entry(svm->iommu, sdev->dev, svm->pasid);
intel_flush_svm_range_dev(svm, sdev, 0, -1, 0, !svm->mm);
}
rcu_read_unlock();
}
static const struct mmu_notifier_ops intel_mmuops = {
.release = intel_mm_release,
.invalidate_range = intel_invalidate_range,
};
static DEFINE_MUTEX(pasid_mutex);
static LIST_HEAD(global_svm_list);
int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_ops *ops)
{
struct intel_iommu *iommu = intel_svm_device_to_iommu(dev);
struct device_domain_info *info;
struct intel_svm_dev *sdev;
struct intel_svm *svm = NULL;
struct mm_struct *mm = NULL;
int pasid_max;
int ret;
if (!iommu || dmar_disabled)
return -EINVAL;
if (dev_is_pci(dev)) {
pasid_max = pci_max_pasids(to_pci_dev(dev));
if (pasid_max < 0)
return -EINVAL;
} else
pasid_max = 1 << 20;
if (flags & SVM_FLAG_SUPERVISOR_MODE) {
if (!ecap_srs(iommu->ecap))
return -EINVAL;
} else if (pasid) {
mm = get_task_mm(current);
BUG_ON(!mm);
}
mutex_lock(&pasid_mutex);
if (pasid && !(flags & SVM_FLAG_PRIVATE_PASID)) {
struct intel_svm *t;
list_for_each_entry(t, &global_svm_list, list) {
if (t->mm != mm || (t->flags & SVM_FLAG_PRIVATE_PASID))
continue;
svm = t;
if (svm->pasid >= pasid_max) {
dev_warn(dev,
"Limited PASID width. Cannot use existing PASID %d\n",
svm->pasid);
ret = -ENOSPC;
goto out;
}
list_for_each_entry(sdev, &svm->devs, list) {
if (dev == sdev->dev) {
if (sdev->ops != ops) {
ret = -EBUSY;
goto out;
}
sdev->users++;
goto success;
}
}
break;
}
}
sdev = kzalloc(sizeof(*sdev), GFP_KERNEL);
if (!sdev) {
ret = -ENOMEM;
goto out;
}
sdev->dev = dev;
ret = intel_iommu_enable_pasid(iommu, dev);
if (ret || !pasid) {
/* If they don't actually want to assign a PASID, this is
* just an enabling check/preparation. */
kfree(sdev);
goto out;
}
info = dev->archdata.iommu;
if (!info || !info->pasid_supported) {
kfree(sdev);
goto out;
}
sdev->did = FLPT_DEFAULT_DID;
sdev->sid = PCI_DEVID(info->bus, info->devfn);
if (info->ats_enabled) {
sdev->dev_iotlb = 1;
sdev->qdep = info->ats_qdep;
if (sdev->qdep >= QI_DEV_EIOTLB_MAX_INVS)
sdev->qdep = 0;
}
/* Finish the setup now we know we're keeping it */
sdev->users = 1;
sdev->ops = ops;
init_rcu_head(&sdev->rcu);
if (!svm) {
svm = kzalloc(sizeof(*svm), GFP_KERNEL);
if (!svm) {
ret = -ENOMEM;
kfree(sdev);
goto out;
}
svm->iommu = iommu;
if (pasid_max > intel_pasid_max_id)
pasid_max = intel_pasid_max_id;
/* Do not use PASID 0 in caching mode (virtualised IOMMU) */
ret = intel_pasid_alloc_id(svm,
!!cap_caching_mode(iommu->cap),
pasid_max - 1, GFP_KERNEL);
if (ret < 0) {
kfree(svm);
kfree(sdev);
goto out;
}
svm->pasid = ret;
svm->notifier.ops = &intel_mmuops;
svm->mm = mm;
svm->flags = flags;
INIT_LIST_HEAD_RCU(&svm->devs);
INIT_LIST_HEAD(&svm->list);
ret = -ENOMEM;
if (mm) {
ret = mmu_notifier_register(&svm->notifier, mm);
if (ret) {
intel_pasid_free_id(svm->pasid);
kfree(svm);
kfree(sdev);
goto out;
}
}
spin_lock(&iommu->lock);
ret = intel_pasid_setup_first_level(iommu, dev,
mm ? mm->pgd : init_mm.pgd,
svm->pasid, FLPT_DEFAULT_DID,
mm ? 0 : PASID_FLAG_SUPERVISOR_MODE);
spin_unlock(&iommu->lock);
if (ret) {
if (mm)
mmu_notifier_unregister(&svm->notifier, mm);
intel_pasid_free_id(svm->pasid);
kfree(svm);
kfree(sdev);
goto out;
}
list_add_tail(&svm->list, &global_svm_list);
}
list_add_rcu(&sdev->list, &svm->devs);
success:
*pasid = svm->pasid;
ret = 0;
out:
mutex_unlock(&pasid_mutex);
if (mm)
mmput(mm);
return ret;
}
EXPORT_SYMBOL_GPL(intel_svm_bind_mm);
int intel_svm_unbind_mm(struct device *dev, int pasid)
{
struct intel_svm_dev *sdev;
struct intel_iommu *iommu;
struct intel_svm *svm;
int ret = -EINVAL;
mutex_lock(&pasid_mutex);
iommu = intel_svm_device_to_iommu(dev);
if (!iommu)
goto out;
svm = intel_pasid_lookup_id(pasid);
if (!svm)
goto out;
list_for_each_entry(sdev, &svm->devs, list) {
if (dev == sdev->dev) {
ret = 0;
sdev->users--;
if (!sdev->users) {
list_del_rcu(&sdev->list);
/* Flush the PASID cache and IOTLB for this device.
* Note that we do depend on the hardware *not* using
* the PASID any more. Just as we depend on other
* devices never using PASIDs that they have no right
* to use. We have a *shared* PASID table, because it's
* large and has to be physically contiguous. So it's
* hard to be as defensive as we might like. */
intel_pasid_tear_down_entry(iommu, dev, svm->pasid);
intel_flush_svm_range_dev(svm, sdev, 0, -1, 0, !svm->mm);
kfree_rcu(sdev, rcu);
if (list_empty(&svm->devs)) {
intel_pasid_free_id(svm->pasid);
if (svm->mm)
mmu_notifier_unregister(&svm->notifier, svm->mm);
list_del(&svm->list);
/* We mandate that no page faults may be outstanding
* for the PASID when intel_svm_unbind_mm() is called.
* If that is not obeyed, subtle errors will happen.
* Let's make them less subtle... */
memset(svm, 0x6b, sizeof(*svm));
kfree(svm);
}
}
break;
}
}
out:
mutex_unlock(&pasid_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(intel_svm_unbind_mm);
int intel_svm_is_pasid_valid(struct device *dev, int pasid)
{
struct intel_iommu *iommu;
struct intel_svm *svm;
int ret = -EINVAL;
mutex_lock(&pasid_mutex);
iommu = intel_svm_device_to_iommu(dev);
if (!iommu)
goto out;
svm = intel_pasid_lookup_id(pasid);
if (!svm)
goto out;
/* init_mm is used in this case */
if (!svm->mm)
ret = 1;
else if (atomic_read(&svm->mm->mm_users) > 0)
ret = 1;
else
ret = 0;
out:
mutex_unlock(&pasid_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(intel_svm_is_pasid_valid);
/* Page request queue descriptor */
struct page_req_dsc {
union {
struct {
u64 type:8;
u64 pasid_present:1;
u64 priv_data_present:1;
u64 rsvd:6;
u64 rid:16;
u64 pasid:20;
u64 exe_req:1;
u64 pm_req:1;
u64 rsvd2:10;
};
u64 qw_0;
};
union {
struct {
u64 rd_req:1;
u64 wr_req:1;
u64 lpig:1;
u64 prg_index:9;
u64 addr:52;
};
u64 qw_1;
};
u64 priv_data[2];
};
#define PRQ_RING_MASK ((0x1000 << PRQ_ORDER) - 0x10)
static bool access_error(struct vm_area_struct *vma, struct page_req_dsc *req)
{
unsigned long requested = 0;
if (req->exe_req)
requested |= VM_EXEC;
if (req->rd_req)
requested |= VM_READ;
if (req->wr_req)
requested |= VM_WRITE;
return (requested & ~vma->vm_flags) != 0;
}
static bool is_canonical_address(u64 addr)
{
int shift = 64 - (__VIRTUAL_MASK_SHIFT + 1);
long saddr = (long) addr;
return (((saddr << shift) >> shift) == saddr);
}
static irqreturn_t prq_event_thread(int irq, void *d)
{
struct intel_iommu *iommu = d;
struct intel_svm *svm = NULL;
int head, tail, handled = 0;
/* Clear PPR bit before reading head/tail registers, to
* ensure that we get a new interrupt if needed. */
writel(DMA_PRS_PPR, iommu->reg + DMAR_PRS_REG);
tail = dmar_readq(iommu->reg + DMAR_PQT_REG) & PRQ_RING_MASK;
head = dmar_readq(iommu->reg + DMAR_PQH_REG) & PRQ_RING_MASK;
while (head != tail) {
struct intel_svm_dev *sdev;
struct vm_area_struct *vma;
struct page_req_dsc *req;
struct qi_desc resp;
int result;
vm_fault_t ret;
u64 address;
handled = 1;
req = &iommu->prq[head / sizeof(*req)];
result = QI_RESP_FAILURE;
address = (u64)req->addr << VTD_PAGE_SHIFT;
if (!req->pasid_present) {
pr_err("%s: Page request without PASID: %08llx %08llx\n",
iommu->name, ((unsigned long long *)req)[0],
((unsigned long long *)req)[1]);
goto no_pasid;
}
if (!svm || svm->pasid != req->pasid) {
rcu_read_lock();
svm = intel_pasid_lookup_id(req->pasid);
/* It *can't* go away, because the driver is not permitted
* to unbind the mm while any page faults are outstanding.
* So we only need RCU to protect the internal idr code. */
rcu_read_unlock();
if (!svm) {
pr_err("%s: Page request for invalid PASID %d: %08llx %08llx\n",
iommu->name, req->pasid, ((unsigned long long *)req)[0],
((unsigned long long *)req)[1]);
goto no_pasid;
}
}
result = QI_RESP_INVALID;
/* Since we're using init_mm.pgd directly, we should never take
* any faults on kernel addresses. */
if (!svm->mm)
goto bad_req;
/* If the mm is already defunct, don't handle faults. */
if (!mmget_not_zero(svm->mm))
goto bad_req;
/* If address is not canonical, return invalid response */
if (!is_canonical_address(address))
goto bad_req;
down_read(&svm->mm->mmap_sem);
vma = find_extend_vma(svm->mm, address);
if (!vma || address < vma->vm_start)
goto invalid;
if (access_error(vma, req))
goto invalid;
ret = handle_mm_fault(vma, address,
req->wr_req ? FAULT_FLAG_WRITE : 0);
if (ret & VM_FAULT_ERROR)
goto invalid;
result = QI_RESP_SUCCESS;
invalid:
up_read(&svm->mm->mmap_sem);
mmput(svm->mm);
bad_req:
/* Accounting for major/minor faults? */
rcu_read_lock();
list_for_each_entry_rcu(sdev, &svm->devs, list) {
if (sdev->sid == req->rid)
break;
}
/* Other devices can go away, but the drivers are not permitted
* to unbind while any page faults might be in flight. So it's
* OK to drop the 'lock' here now we have it. */
rcu_read_unlock();
if (WARN_ON(&sdev->list == &svm->devs))
sdev = NULL;
if (sdev && sdev->ops && sdev->ops->fault_cb) {
int rwxp = (req->rd_req << 3) | (req->wr_req << 2) |
(req->exe_req << 1) | (req->pm_req);
sdev->ops->fault_cb(sdev->dev, req->pasid, req->addr,
req->priv_data, rwxp, result);
}
/* We get here in the error case where the PASID lookup failed,
and these can be NULL. Do not use them below this point! */
sdev = NULL;
svm = NULL;
no_pasid:
if (req->lpig || req->priv_data_present) {
/*
* Per VT-d spec. v3.0 ch7.7, system software must
* respond with page group response if private data
* is present (PDP) or last page in group (LPIG) bit
* is set. This is an additional VT-d feature beyond
* PCI ATS spec.
*/
resp.qw0 = QI_PGRP_PASID(req->pasid) |
QI_PGRP_DID(req->rid) |
QI_PGRP_PASID_P(req->pasid_present) |
QI_PGRP_PDP(req->pasid_present) |
QI_PGRP_RESP_CODE(result) |
QI_PGRP_RESP_TYPE;
resp.qw1 = QI_PGRP_IDX(req->prg_index) |
QI_PGRP_LPIG(req->lpig);
if (req->priv_data_present)
memcpy(&resp.qw2, req->priv_data,
sizeof(req->priv_data));
}
resp.qw2 = 0;
resp.qw3 = 0;
qi_submit_sync(&resp, iommu);
head = (head + sizeof(*req)) & PRQ_RING_MASK;
}
dmar_writeq(iommu->reg + DMAR_PQH_REG, tail);
return IRQ_RETVAL(handled);
}
