[PATCH v6 5/6] nouveau: use new mmu interval notifiers

From: Ralph Campbell
Date: Mon Jan 13 2020 - 17:47:35 EST

Update nouveau to only use the mmu interval notifiers.

Signed-off-by: Ralph Campbell <rcampbell@xxxxxxxxxx>
---
drivers/gpu/drm/nouveau/nouveau_svm.c | 313 +++++++++++++++++---------
1 file changed, 201 insertions(+), 112 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_svm.c b/drivers/gpu/drm/nouveau/nouveau_svm.c
index df9bf1fd1bc0..0343e48d41d7 100644
--- a/drivers/gpu/drm/nouveau/nouveau_svm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_svm.c
@@ -88,7 +88,7 @@ nouveau_ivmm_find(struct nouveau_svm *svm, u64 inst)
}

struct nouveau_svmm {
- struct mmu_notifier notifier;
+ struct mm_struct *mm;
struct nouveau_vmm *vmm;
struct {
unsigned long start;
@@ -98,6 +98,13 @@ struct nouveau_svmm {
struct mutex mutex;
};

+struct svmm_interval {
+ struct mmu_interval_notifier notifier;
+ struct nouveau_svmm *svmm;
+};
+
+static const struct mmu_interval_notifier_ops nouveau_svm_mni_ops;
+
#define SVMM_DBG(s,f,a...) \
NV_DEBUG((s)->vmm->cli->drm, "svm-%p: "f"\n", (s), ##a)
#define SVMM_ERR(s,f,a...) \
@@ -236,6 +243,8 @@ nouveau_svmm_join(struct nouveau_svmm *svmm, u64 inst)
static void
nouveau_svmm_invalidate(struct nouveau_svmm *svmm, u64 start, u64 limit)
{
+ SVMM_DBG(svmm, "invalidate %016llx-%016llx", start, limit);
+
if (limit > start) {
bool super = svmm->vmm->vmm.object.client->super;
svmm->vmm->vmm.object.client->super = true;
@@ -248,58 +257,25 @@ nouveau_svmm_invalidate(struct nouveau_svmm *svmm, u64 start, u64 limit)
}
}

-static int
-nouveau_svmm_invalidate_range_start(struct mmu_notifier *mn,
- const struct mmu_notifier_range *update)
-{
- struct nouveau_svmm *svmm =
- container_of(mn, struct nouveau_svmm, notifier);
- unsigned long start = update->start;
- unsigned long limit = update->end;
-
- if (!mmu_notifier_range_blockable(update))
- return -EAGAIN;
-
- SVMM_DBG(svmm, "invalidate %016lx-%016lx", start, limit);
-
- mutex_lock(&svmm->mutex);
- if (unlikely(!svmm->vmm))
- goto out;
-
- if (limit > svmm->unmanaged.start && start < svmm->unmanaged.limit) {
- if (start < svmm->unmanaged.start) {
- nouveau_svmm_invalidate(svmm, start,
- svmm->unmanaged.limit);
- }
- start = svmm->unmanaged.limit;
- }
-
- nouveau_svmm_invalidate(svmm, start, limit);
-
-out:
- mutex_unlock(&svmm->mutex);
- return 0;
-}
-
-static void nouveau_svmm_free_notifier(struct mmu_notifier *mn)
-{
- kfree(container_of(mn, struct nouveau_svmm, notifier));
-}
-
-static const struct mmu_notifier_ops nouveau_mn_ops = {
- .invalidate_range_start = nouveau_svmm_invalidate_range_start,
- .free_notifier = nouveau_svmm_free_notifier,
-};
-
void
nouveau_svmm_fini(struct nouveau_svmm **psvmm)
{
struct nouveau_svmm *svmm = *psvmm;
+ struct mmu_interval_notifier *mni;
+
if (svmm) {
mutex_lock(&svmm->mutex);
+ while (true) {
+ mni = mmu_interval_notifier_find(svmm->mm,
+ &nouveau_svm_mni_ops, 0UL, ~0UL);
+ if (!mni)
+ break;
+ mmu_interval_notifier_put(mni);
+ }
svmm->vmm = NULL;
mutex_unlock(&svmm->mutex);
- mmu_notifier_put(&svmm->notifier);
+ mmdrop(svmm->mm);
+ kfree(svmm);
*psvmm = NULL;
}
}
@@ -343,11 +319,12 @@ nouveau_svmm_init(struct drm_device *dev, void *data,
goto out_free;

down_write(&current->mm->mmap_sem);
- svmm->notifier.ops = &nouveau_mn_ops;
- ret = __mmu_notifier_register(&svmm->notifier, current->mm);
+ ret = __mmu_notifier_register(NULL, current->mm);
if (ret)
goto out_mm_unlock;
- /* Note, ownership of svmm transfers to mmu_notifier */
+
+ mmgrab(current->mm);
+ svmm->mm = current->mm;

cli->svm.svmm = svmm;
cli->svm.cli = cli;
@@ -482,65 +459,212 @@ nouveau_svm_fault_cache(struct nouveau_svm *svm,
fault->inst, fault->addr, fault->access);
}

-struct svm_notifier {
- struct mmu_interval_notifier notifier;
- struct nouveau_svmm *svmm;
-};
+static struct svmm_interval *nouveau_svmm_new_interval(
+ struct nouveau_svmm *svmm,
+ unsigned long start,
+ unsigned long last)
+{
+ struct svmm_interval *smi;
+ int ret;
+
+ smi = kmalloc(sizeof(*smi), GFP_ATOMIC);
+ if (!smi)
+ return NULL;
+
+ smi->svmm = svmm;
+
+ ret = mmu_interval_notifier_insert_safe(&smi->notifier, svmm->mm,
+ start, last - start + 1, &nouveau_svm_mni_ops);
+ if (ret) {
+ kfree(smi);
+ return NULL;
+ }
+
+ return smi;
+}
+
+static void nouveau_svmm_do_unmap(struct mmu_interval_notifier *mni,
+ const struct mmu_notifier_range *range)
+{
+ struct svmm_interval *smi =
+ container_of(mni, struct svmm_interval, notifier);
+ struct nouveau_svmm *svmm = smi->svmm;
+ unsigned long start = mmu_interval_notifier_start(mni);
+ unsigned long last = mmu_interval_notifier_last(mni);
+
+ if (start >= range->start) {
+ /* Remove the whole interval or keep the right-hand part. */
+ if (last <= range->end)
+ mmu_interval_notifier_put(mni);
+ else
+ mmu_interval_notifier_update(mni, range->end, last);
+ return;
+ }
+
+ /* Keep the left-hand part of the interval. */
+ mmu_interval_notifier_update(mni, start, range->start - 1);
+
+ /* If a hole is created, create an interval for the right-hand part. */
+ if (last >= range->end) {
+ smi = nouveau_svmm_new_interval(svmm, range->end, last);
+ /*
+ * If we can't allocate an interval, we won't get invalidation
+ * callbacks so clear the mapping and rely on faults to reload
+ * the mappings if needed.
+ */
+ if (!smi)
+ nouveau_svmm_invalidate(svmm, range->end, last + 1);
+ }
+}

-static bool nouveau_svm_range_invalidate(struct mmu_interval_notifier *mni,
- const struct mmu_notifier_range *range,
- unsigned long cur_seq)
+static bool nouveau_svmm_interval_invalidate(struct mmu_interval_notifier *mni,
+ const struct mmu_notifier_range *range,
+ unsigned long cur_seq)
{
- struct svm_notifier *sn =
- container_of(mni, struct svm_notifier, notifier);
+ struct svmm_interval *smi =
+ container_of(mni, struct svmm_interval, notifier);
+ struct nouveau_svmm *svmm = smi->svmm;

/*
- * serializes the update to mni->invalidate_seq done by caller and
+ * Serializes the update to mni->invalidate_seq done by the caller and
* prevents invalidation of the PTE from progressing while HW is being
- * programmed. This is very hacky and only works because the normal
- * notifier that does invalidation is always called after the range
- * notifier.
+ * programmed.
*/
if (mmu_notifier_range_blockable(range))
- mutex_lock(&sn->svmm->mutex);
- else if (!mutex_trylock(&sn->svmm->mutex))
+ mutex_lock(&svmm->mutex);
+ else if (!mutex_trylock(&svmm->mutex))
return false;
+
mmu_interval_set_seq(mni, cur_seq);
- mutex_unlock(&sn->svmm->mutex);
+ nouveau_svmm_invalidate(svmm, range->start, range->end);
+
+ /* Stop tracking the range if it is an unmap. */
+ if (range->event == MMU_NOTIFY_UNMAP)
+ nouveau_svmm_do_unmap(mni, range);
+
+ mutex_unlock(&svmm->mutex);
return true;
}

+static void nouveau_svmm_interval_release(struct mmu_interval_notifier *mni)
+{
+ struct svmm_interval *smi =
+ container_of(mni, struct svmm_interval, notifier);
+
+ kfree(smi);
+}
+
static const struct mmu_interval_notifier_ops nouveau_svm_mni_ops = {
- .invalidate = nouveau_svm_range_invalidate,
+ .invalidate = nouveau_svmm_interval_invalidate,
+ .release = nouveau_svmm_interval_release,
};

+/*
+ * Find or create a mmu_interval_notifier for the given range.
+ * Although mmu_interval_notifier_insert_safe() can handle overlapping
+ * intervals, we only create non-overlapping intervals, shrinking the hmm_range
+ * if it spans more than one svmm_interval.
+ */
+static int nouveau_svmm_interval_find(struct nouveau_svmm *svmm,
+ struct hmm_range *range)
+{
+ struct mmu_interval_notifier *mni;
+ struct svmm_interval *smi;
+ struct vm_area_struct *vma;
+ unsigned long start = range->start;
+ unsigned long last = range->end - 1;
+ int ret;
+
+ mutex_lock(&svmm->mutex);
+ mni = mmu_interval_notifier_find(svmm->mm, &nouveau_svm_mni_ops, start,
+ last);
+ if (mni) {
+ if (start >= mmu_interval_notifier_start(mni)) {
+ smi = container_of(mni, struct svmm_interval, notifier);
+ if (last > mmu_interval_notifier_last(mni))
+ range->end =
+ mmu_interval_notifier_last(mni) + 1;
+ goto found;
+ }
+ WARN_ON(last <= mmu_interval_notifier_start(mni));
+ range->end = mmu_interval_notifier_start(mni);
+ last = range->end - 1;
+ }
+ /*
+ * Might as well create an interval covering the underlying VMA to
+ * avoid having to create a bunch of small intervals.
+ */
+ vma = find_vma(svmm->mm, range->start);
+ if (!vma || start < vma->vm_start) {
+ ret = -ENOENT;
+ goto err;
+ }
+ if (range->end > vma->vm_end) {
+ range->end = vma->vm_end;
+ last = range->end - 1;
+ } else if (!mni) {
+ /* Anything registered on the right part of the vma? */
+ mni = mmu_interval_notifier_find(svmm->mm, &nouveau_svm_mni_ops,
+ range->end, vma->vm_end - 1);
+ if (mni)
+ last = mmu_interval_notifier_start(mni) - 1;
+ else
+ last = vma->vm_end - 1;
+ }
+ /* Anything registered on the left part of the vma? */
+ mni = mmu_interval_notifier_find(svmm->mm, &nouveau_svm_mni_ops,
+ vma->vm_start, start - 1);
+ if (mni)
+ start = mmu_interval_notifier_last(mni) + 1;
+ else
+ start = vma->vm_start;
+ smi = nouveau_svmm_new_interval(svmm, start, last);
+ if (!smi) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+found:
+ range->notifier = &smi->notifier;
+ mutex_unlock(&svmm->mutex);
+ return 0;
+
+err:
+ mutex_unlock(&svmm->mutex);
+ return ret;
+}
+
static int nouveau_range_fault(struct nouveau_svmm *svmm,
struct nouveau_drm *drm, void *data, u32 size,
- u64 *pfns, struct svm_notifier *notifier)
+ u64 *pfns, u64 start, u64 end)
{
unsigned long timeout =
jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
/* Have HMM fault pages within the fault window to the GPU. */
struct hmm_range range = {
- .notifier = &notifier->notifier,
- .start = notifier->notifier.interval_tree.start,
- .end = notifier->notifier.interval_tree.last + 1,
+ .start = start,
+ .end = end,
.pfns = pfns,
.flags = nouveau_svm_pfn_flags,
.values = nouveau_svm_pfn_values,
+ .default_flags = 0,
+ .pfn_flags_mask = ~0UL,
.pfn_shift = NVIF_VMM_PFNMAP_V0_ADDR_SHIFT,
};
- struct mm_struct *mm = notifier->notifier.mm;
+ struct mm_struct *mm = svmm->mm;
long ret;

while (true) {
if (time_after(jiffies, timeout))
return -EBUSY;

- range.notifier_seq = mmu_interval_read_begin(range.notifier);
- range.default_flags = 0;
- range.pfn_flags_mask = -1UL;
down_read(&mm->mmap_sem);
+ ret = nouveau_svmm_interval_find(svmm, &range);
+ if (ret) {
+ up_read(&mm->mmap_sem);
+ return ret;
+ }
+ range.notifier_seq = mmu_interval_read_begin(range.notifier);
ret = hmm_range_fault(&range, 0);
up_read(&mm->mmap_sem);
if (ret <= 0) {
@@ -585,7 +709,6 @@ nouveau_svm_fault(struct nvif_notify *notify)
} i;
u64 phys[16];
} args;
- struct vm_area_struct *vma;
u64 inst, start, limit;
int fi, fn, pi, fill;
int replay = 0, ret;
@@ -640,7 +763,6 @@ nouveau_svm_fault(struct nvif_notify *notify)
args.i.p.version = 0;

for (fi = 0; fn = fi + 1, fi < buffer->fault_nr; fi = fn) {
- struct svm_notifier notifier;
struct mm_struct *mm;

/* Cancel any faults from non-SVM channels. */
@@ -662,36 +784,12 @@ nouveau_svm_fault(struct nvif_notify *notify)
start = max_t(u64, start, svmm->unmanaged.limit);
SVMM_DBG(svmm, "wndw %016llx-%016llx", start, limit);

- mm = svmm->notifier.mm;
+ mm = svmm->mm;
if (!mmget_not_zero(mm)) {
nouveau_svm_fault_cancel_fault(svm, buffer->fault[fi]);
continue;
}

- /* Intersect fault window with the CPU VMA, cancelling
- * the fault if the address is invalid.
- */
- down_read(&mm->mmap_sem);
- vma = find_vma_intersection(mm, start, limit);
- if (!vma) {
- SVMM_ERR(svmm, "wndw %016llx-%016llx", start, limit);
- up_read(&mm->mmap_sem);
- mmput(mm);
- nouveau_svm_fault_cancel_fault(svm, buffer->fault[fi]);
- continue;
- }
- start = max_t(u64, start, vma->vm_start);
- limit = min_t(u64, limit, vma->vm_end);
- up_read(&mm->mmap_sem);
- SVMM_DBG(svmm, "wndw %016llx-%016llx", start, limit);
-
- if (buffer->fault[fi]->addr != start) {
- SVMM_ERR(svmm, "addr %016llx", buffer->fault[fi]->addr);
- mmput(mm);
- nouveau_svm_fault_cancel_fault(svm, buffer->fault[fi]);
- continue;
- }
-
/* Prepare the GPU-side update of all pages within the
* fault window, determining required pages and access
* permissions based on pending faults.
@@ -743,18 +841,9 @@ nouveau_svm_fault(struct nvif_notify *notify)
args.i.p.addr,
args.i.p.addr + args.i.p.size, fn - fi);

- notifier.svmm = svmm;
- ret = mmu_interval_notifier_insert(&notifier.notifier,
- svmm->notifier.mm,
- args.i.p.addr, args.i.p.size,
- &nouveau_svm_mni_ops);
- if (!ret) {
- ret = nouveau_range_fault(
- svmm, svm->drm, &args,
- sizeof(args.i) + pi * sizeof(args.phys[0]),
- args.phys, &notifier);
- mmu_interval_notifier_remove(&notifier.notifier);
- }
+ ret = nouveau_range_fault(svmm, svm->drm, &args,
+ sizeof(args.i) + pi * sizeof(args.phys[0]), args.phys,
+ start, start + args.i.p.size);
mmput(mm);

/* Cancel any faults in the window whose pages didn't manage
--
2.20.1