From: Kenneth Lee <[email protected]>
Uacce (Unified/User-space-access-intended Accelerator Framework) targets to
provide Shared Virtual Addressing (SVA) between accelerators and processes.
So accelerator can access any data structure of the main cpu.
This differs from the data sharing between cpu and io device, which share
data content rather than address.
Since unified address, hardware and user space of process can share the
same virtual address in the communication.
Uacce create a chrdev for every registration, the queue is allocated to
the process when the chrdev is opened. Then the process can access the
hardware resource by interact with the queue file. By mmap the queue
file space to user space, the process can directly put requests to the
hardware without syscall to the kernel space.
Signed-off-by: Kenneth Lee <[email protected]>
Signed-off-by: Zaibo Xu <[email protected]>
Signed-off-by: Zhou Wang <[email protected]>
Signed-off-by: Zhangfei Gao <[email protected]>
---
Documentation/ABI/testing/sysfs-driver-uacce | 65 ++
drivers/misc/Kconfig | 1 +
drivers/misc/Makefile | 1 +
drivers/misc/uacce/Kconfig | 13 +
drivers/misc/uacce/Makefile | 2 +
drivers/misc/uacce/uacce.c | 995 +++++++++++++++++++++++++++
include/linux/uacce.h | 168 +++++
include/uapi/misc/uacce/uacce.h | 41 ++
8 files changed, 1286 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-driver-uacce
create mode 100644 drivers/misc/uacce/Kconfig
create mode 100644 drivers/misc/uacce/Makefile
create mode 100644 drivers/misc/uacce/uacce.c
create mode 100644 include/linux/uacce.h
create mode 100644 include/uapi/misc/uacce/uacce.h
diff --git a/Documentation/ABI/testing/sysfs-driver-uacce b/Documentation/ABI/testing/sysfs-driver-uacce
new file mode 100644
index 0000000..e48333c
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-driver-uacce
@@ -0,0 +1,65 @@
+What: /sys/class/uacce/hisi_zip-<n>/id
+Date: Oct 2019
+KernelVersion: 5.5
+Contact: [email protected]
+Description: Id of the device.
+
+What: /sys/class/uacce/hisi_zip-<n>/api
+Date: Oct 2019
+KernelVersion: 5.5
+Contact: [email protected]
+Description: Api of the device, used by application to match the correct driver
+
+What: /sys/class/uacce/hisi_zip-<n>/flags
+Date: Oct 2019
+KernelVersion: 5.5
+Contact: [email protected]
+Description: Attributes of the device, see UACCE_DEV_xxx flag defined in uacce.h
+
+What: /sys/class/uacce/hisi_zip-<n>/available_instances
+Date: Oct 2019
+KernelVersion: 5.5
+Contact: [email protected]
+Description: Available instances left of the device
+
+What: /sys/class/uacce/hisi_zip-<n>/algorithms
+Date: Oct 2019
+KernelVersion: 5.5
+Contact: [email protected]
+Description: Algorithms supported by this accelerator
+
+What: /sys/class/uacce/hisi_zip-<n>/qfrt_mmio_size
+Date: Oct 2019
+KernelVersion: 5.5
+Contact: [email protected]
+Description: Page size of mmio region queue file
+
+What: /sys/class/uacce/hisi_zip-<n>/qfrt_dko_size
+Date: Oct 2019
+KernelVersion: 5.5
+Contact: [email protected]
+Description: Page size of dko region queue file
+
+What: /sys/class/uacce/hisi_zip-<n>/qfrt_dus_size
+Date: Oct 2019
+KernelVersion: 5.5
+Contact: [email protected]
+Description: Page size of dus region queue file
+
+What: /sys/class/uacce/hisi_zip-<n>/qfrt_ss_size
+Date: Oct 2019
+KernelVersion: 5.5
+Contact: [email protected]
+Description: Page size of ss region queue file
+
+What: /sys/class/uacce/hisi_zip-<n>/numa_distance
+Date: Oct 2019
+KernelVersion: 5.5
+Contact: [email protected]
+Description: Distance of device node to cpu node
+
+What: /sys/class/uacce/hisi_zip-<n>/node_id
+Date: Oct 2019
+KernelVersion: 5.5
+Contact: [email protected]
+Description: Id of the numa node
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index c55b637..929feb0 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -481,4 +481,5 @@ source "drivers/misc/cxl/Kconfig"
source "drivers/misc/ocxl/Kconfig"
source "drivers/misc/cardreader/Kconfig"
source "drivers/misc/habanalabs/Kconfig"
+source "drivers/misc/uacce/Kconfig"
endmenu
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index c1860d3..9abf292 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -56,4 +56,5 @@ obj-$(CONFIG_OCXL) += ocxl/
obj-y += cardreader/
obj-$(CONFIG_PVPANIC) += pvpanic.o
obj-$(CONFIG_HABANA_AI) += habanalabs/
+obj-$(CONFIG_UACCE) += uacce/
obj-$(CONFIG_XILINX_SDFEC) += xilinx_sdfec.o
diff --git a/drivers/misc/uacce/Kconfig b/drivers/misc/uacce/Kconfig
new file mode 100644
index 0000000..e854354
--- /dev/null
+++ b/drivers/misc/uacce/Kconfig
@@ -0,0 +1,13 @@
+config UACCE
+ tristate "Accelerator Framework for User Land"
+ depends on IOMMU_API
+ help
+ UACCE provides interface for the user process to access the hardware
+ without interaction with the kernel space in data path.
+
+ The user-space interface is described in
+ include/uapi/misc/uacce.h
+
+ See Documentation/misc-devices/uacce.rst for more details.
+
+ If you don't know what to do here, say N.
diff --git a/drivers/misc/uacce/Makefile b/drivers/misc/uacce/Makefile
new file mode 100644
index 0000000..5b4374e
--- /dev/null
+++ b/drivers/misc/uacce/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+obj-$(CONFIG_UACCE) += uacce.o
diff --git a/drivers/misc/uacce/uacce.c b/drivers/misc/uacce/uacce.c
new file mode 100644
index 0000000..534ddc3
--- /dev/null
+++ b/drivers/misc/uacce/uacce.c
@@ -0,0 +1,995 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/compat.h>
+#include <linux/dma-iommu.h>
+#include <linux/file.h>
+#include <linux/irqdomain.h>
+#include <linux/module.h>
+#include <linux/poll.h>
+#include <linux/sched/signal.h>
+#include <linux/uacce.h>
+
+static struct class *uacce_class;
+static DEFINE_IDR(uacce_idr);
+static dev_t uacce_devt;
+static DEFINE_MUTEX(uacce_mutex);
+static const struct file_operations uacce_fops;
+
+static int uacce_queue_map_qfr(struct uacce_queue *q,
+ struct uacce_qfile_region *qfr)
+{
+ struct device *dev = q->uacce->pdev;
+ struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
+ int i, j, ret;
+
+ if (!(qfr->flags & UACCE_QFRF_MAP) || (qfr->flags & UACCE_QFRF_DMA))
+ return 0;
+
+ if (!domain)
+ return -ENODEV;
+
+ for (i = 0; i < qfr->nr_pages; i++) {
+ ret = iommu_map(domain, qfr->iova + i * PAGE_SIZE,
+ page_to_phys(qfr->pages[i]),
+ PAGE_SIZE, qfr->prot | q->uacce->prot);
+ if (ret)
+ goto err_with_map_pages;
+
+ get_page(qfr->pages[i]);
+ }
+
+ return 0;
+
+err_with_map_pages:
+ for (j = i - 1; j >= 0; j--) {
+ iommu_unmap(domain, qfr->iova + j * PAGE_SIZE, PAGE_SIZE);
+ put_page(qfr->pages[j]);
+ }
+ return ret;
+}
+
+static void uacce_queue_unmap_qfr(struct uacce_queue *q,
+ struct uacce_qfile_region *qfr)
+{
+ struct device *dev = q->uacce->pdev;
+ struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
+ int i;
+
+ if (!domain || !qfr)
+ return;
+
+ if (!(qfr->flags & UACCE_QFRF_MAP) || (qfr->flags & UACCE_QFRF_DMA))
+ return;
+
+ for (i = qfr->nr_pages - 1; i >= 0; i--) {
+ iommu_unmap(domain, qfr->iova + i * PAGE_SIZE, PAGE_SIZE);
+ put_page(qfr->pages[i]);
+ }
+}
+
+static int uacce_qfr_alloc_pages(struct uacce_qfile_region *qfr)
+{
+ int i, j;
+
+ qfr->pages = kcalloc(qfr->nr_pages, sizeof(*qfr->pages), GFP_ATOMIC);
+ if (!qfr->pages)
+ return -ENOMEM;
+
+ for (i = 0; i < qfr->nr_pages; i++) {
+ qfr->pages[i] = alloc_page(GFP_ATOMIC | __GFP_ZERO);
+ if (!qfr->pages[i])
+ goto err_with_pages;
+ }
+
+ return 0;
+
+err_with_pages:
+ for (j = i - 1; j >= 0; j--)
+ put_page(qfr->pages[j]);
+
+ kfree(qfr->pages);
+ return -ENOMEM;
+}
+
+static void uacce_qfr_free_pages(struct uacce_qfile_region *qfr)
+{
+ int i;
+
+ for (i = 0; i < qfr->nr_pages; i++)
+ put_page(qfr->pages[i]);
+
+ kfree(qfr->pages);
+}
+
+static inline int uacce_queue_mmap_qfr(struct uacce_queue *q,
+ struct uacce_qfile_region *qfr,
+ struct vm_area_struct *vma)
+{
+ int i, ret;
+
+ for (i = 0; i < qfr->nr_pages; i++) {
+ ret = remap_pfn_range(vma, vma->vm_start + (i << PAGE_SHIFT),
+ page_to_pfn(qfr->pages[i]), PAGE_SIZE,
+ vma->vm_page_prot);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static struct uacce_qfile_region *
+uacce_create_region(struct uacce_queue *q, struct vm_area_struct *vma,
+ enum uacce_qfrt type, unsigned int flags)
+{
+ struct uacce_qfile_region *qfr;
+ struct uacce_device *uacce = q->uacce;
+ unsigned long vm_pgoff;
+ int ret = -ENOMEM;
+
+ qfr = kzalloc(sizeof(*qfr), GFP_ATOMIC);
+ if (!qfr)
+ return ERR_PTR(-ENOMEM);
+
+ qfr->type = type;
+ qfr->flags = flags;
+ qfr->iova = vma->vm_start;
+ qfr->nr_pages = vma_pages(vma);
+
+ if (vma->vm_flags & VM_READ)
+ qfr->prot |= IOMMU_READ;
+
+ if (vma->vm_flags & VM_WRITE)
+ qfr->prot |= IOMMU_WRITE;
+
+ if (flags & UACCE_QFRF_SELFMT) {
+ if (!uacce->ops->mmap) {
+ ret = -EINVAL;
+ goto err_with_qfr;
+ }
+
+ ret = uacce->ops->mmap(q, vma, qfr);
+ if (ret)
+ goto err_with_qfr;
+ return qfr;
+ }
+
+ /* allocate memory */
+ if (flags & UACCE_QFRF_DMA) {
+ qfr->kaddr = dma_alloc_coherent(uacce->pdev,
+ qfr->nr_pages << PAGE_SHIFT,
+ &qfr->dma, GFP_KERNEL);
+ if (!qfr->kaddr) {
+ ret = -ENOMEM;
+ goto err_with_qfr;
+ }
+ } else {
+ ret = uacce_qfr_alloc_pages(qfr);
+ if (ret)
+ goto err_with_qfr;
+ }
+
+ /* map to device */
+ ret = uacce_queue_map_qfr(q, qfr);
+ if (ret)
+ goto err_with_pages;
+
+ /* mmap to user space */
+ if (flags & UACCE_QFRF_MMAP) {
+ if (flags & UACCE_QFRF_DMA) {
+ /* dma_mmap_coherent() requires vm_pgoff as 0
+ * restore vm_pfoff to initial value for mmap()
+ */
+ vm_pgoff = vma->vm_pgoff;
+ vma->vm_pgoff = 0;
+ ret = dma_mmap_coherent(uacce->pdev, vma, qfr->kaddr,
+ qfr->dma,
+ qfr->nr_pages << PAGE_SHIFT);
+ vma->vm_pgoff = vm_pgoff;
+ } else {
+ ret = uacce_queue_mmap_qfr(q, qfr, vma);
+ }
+
+ if (ret)
+ goto err_with_mapped_qfr;
+ }
+
+ return qfr;
+
+err_with_mapped_qfr:
+ uacce_queue_unmap_qfr(q, qfr);
+err_with_pages:
+ if (flags & UACCE_QFRF_DMA)
+ dma_free_coherent(uacce->pdev, qfr->nr_pages << PAGE_SHIFT,
+ qfr->kaddr, qfr->dma);
+ else
+ uacce_qfr_free_pages(qfr);
+err_with_qfr:
+ kfree(qfr);
+
+ return ERR_PTR(ret);
+}
+
+static void uacce_destroy_region(struct uacce_queue *q,
+ struct uacce_qfile_region *qfr)
+{
+ struct uacce_device *uacce = q->uacce;
+
+ if (qfr->flags & UACCE_QFRF_DMA) {
+ dma_free_coherent(uacce->pdev, qfr->nr_pages << PAGE_SHIFT,
+ qfr->kaddr, qfr->dma);
+ } else if (qfr->pages) {
+ if (qfr->flags & UACCE_QFRF_KMAP && qfr->kaddr) {
+ vunmap(qfr->kaddr);
+ qfr->kaddr = NULL;
+ }
+
+ uacce_qfr_free_pages(qfr);
+ }
+ kfree(qfr);
+}
+
+static long uacce_cmd_share_qfr(struct uacce_queue *tgt, int fd)
+{
+ struct file *filep;
+ struct uacce_queue *src;
+ int ret = -EINVAL;
+
+ mutex_lock(&uacce_mutex);
+
+ if (tgt->state != UACCE_Q_STARTED)
+ goto out_with_lock;
+
+ filep = fget(fd);
+ if (!filep)
+ goto out_with_lock;
+
+ if (filep->f_op != &uacce_fops)
+ goto out_with_fd;
+
+ src = filep->private_data;
+ if (!src)
+ goto out_with_fd;
+
+ if (tgt->uacce->flags & UACCE_DEV_SVA)
+ goto out_with_fd;
+
+ if (!src->qfrs[UACCE_QFRT_SS] || tgt->qfrs[UACCE_QFRT_SS])
+ goto out_with_fd;
+
+ ret = uacce_queue_map_qfr(tgt, src->qfrs[UACCE_QFRT_SS]);
+ if (ret)
+ goto out_with_fd;
+
+ tgt->qfrs[UACCE_QFRT_SS] = src->qfrs[UACCE_QFRT_SS];
+ list_add(&tgt->list, &src->qfrs[UACCE_QFRT_SS]->qs);
+
+out_with_fd:
+ fput(filep);
+out_with_lock:
+ mutex_unlock(&uacce_mutex);
+ return ret;
+}
+
+static int uacce_start_queue(struct uacce_queue *q)
+{
+ struct uacce_qfile_region *qfr;
+ int ret = -EINVAL;
+ int i, j;
+
+ mutex_lock(&uacce_mutex);
+
+ if (q->state != UACCE_Q_INIT)
+ goto out_with_lock;
+
+ /*
+ * map KMAP qfr to kernel
+ * vmap should be done in non-spinlocked context!
+ */
+ for (i = 0; i < UACCE_QFRT_MAX; i++) {
+ qfr = q->qfrs[i];
+ if (qfr && (qfr->flags & UACCE_QFRF_KMAP) && !qfr->kaddr) {
+ qfr->kaddr = vmap(qfr->pages, qfr->nr_pages, VM_MAP,
+ PAGE_KERNEL);
+ if (!qfr->kaddr) {
+ ret = -ENOMEM;
+ goto err_with_vmap;
+ }
+ }
+ }
+
+ if (q->uacce->ops->start_queue) {
+ ret = q->uacce->ops->start_queue(q);
+ if (ret < 0)
+ goto err_with_vmap;
+ }
+
+ q->state = UACCE_Q_STARTED;
+ mutex_unlock(&uacce_mutex);
+
+ return 0;
+
+err_with_vmap:
+ for (j = i; j >= 0; j--) {
+ qfr = q->qfrs[j];
+ if (qfr && qfr->kaddr) {
+ vunmap(qfr->kaddr);
+ qfr->kaddr = NULL;
+ }
+ }
+out_with_lock:
+ mutex_unlock(&uacce_mutex);
+ return ret;
+}
+
+static long uacce_put_queue(struct uacce_queue *q)
+{
+ struct uacce_device *uacce = q->uacce;
+
+ mutex_lock(&uacce_mutex);
+
+ if ((q->state == UACCE_Q_STARTED) && uacce->ops->stop_queue)
+ uacce->ops->stop_queue(q);
+
+ if ((q->state == UACCE_Q_INIT || q->state == UACCE_Q_STARTED) &&
+ uacce->ops->put_queue)
+ uacce->ops->put_queue(q);
+
+ q->state = UACCE_Q_ZOMBIE;
+ mutex_unlock(&uacce_mutex);
+
+ return 0;
+}
+
+static long uacce_fops_unl_ioctl(struct file *filep,
+ unsigned int cmd, unsigned long arg)
+{
+ struct uacce_queue *q = filep->private_data;
+ struct uacce_device *uacce = q->uacce;
+
+ switch (cmd) {
+ case UACCE_CMD_SHARE_SVAS:
+ return uacce_cmd_share_qfr(q, arg);
+
+ case UACCE_CMD_START:
+ return uacce_start_queue(q);
+
+ case UACCE_CMD_PUT_Q:
+ return uacce_put_queue(q);
+
+ default:
+ if (!uacce->ops->ioctl)
+ return -EINVAL;
+
+ return uacce->ops->ioctl(q, cmd, arg);
+ }
+}
+
+#ifdef CONFIG_COMPAT
+static long uacce_fops_compat_ioctl(struct file *filep,
+ unsigned int cmd, unsigned long arg)
+{
+ arg = (unsigned long)compat_ptr(arg);
+
+ return uacce_fops_unl_ioctl(filep, cmd, arg);
+}
+#endif
+
+static int uacce_dev_open_check(struct uacce_device *uacce)
+{
+ if (uacce->flags & UACCE_DEV_SVA)
+ return 0;
+
+ /*
+ * The device can be opened once if it does not support pasid
+ */
+ if (kref_read(&uacce->cdev->kobj.kref) > 2)
+ return -EBUSY;
+
+ return 0;
+}
+
+static int uacce_fops_open(struct inode *inode, struct file *filep)
+{
+ struct uacce_queue *q;
+ struct iommu_sva *handle = NULL;
+ struct uacce_device *uacce;
+ int ret;
+ int pasid = 0;
+
+ uacce = idr_find(&uacce_idr, iminor(inode));
+ if (!uacce)
+ return -ENODEV;
+
+ if (!try_module_get(uacce->pdev->driver->owner))
+ return -ENODEV;
+
+ ret = uacce_dev_open_check(uacce);
+ if (ret)
+ goto out_with_module;
+
+ if (uacce->flags & UACCE_DEV_SVA) {
+ handle = iommu_sva_bind_device(uacce->pdev, current->mm, NULL);
+ if (IS_ERR(handle))
+ goto out_with_module;
+ pasid = iommu_sva_get_pasid(handle);
+ }
+
+ q = kzalloc(sizeof(struct uacce_queue), GFP_KERNEL);
+ if (!q) {
+ ret = -ENOMEM;
+ goto out_with_module;
+ }
+
+ if (uacce->ops->get_queue) {
+ ret = uacce->ops->get_queue(uacce, pasid, q);
+ if (ret < 0)
+ goto out_with_mem;
+ }
+
+ q->pasid = pasid;
+ q->handle = handle;
+ q->uacce = uacce;
+ q->mm = current->mm;
+ memset(q->qfrs, 0, sizeof(q->qfrs));
+ INIT_LIST_HEAD(&q->list);
+ init_waitqueue_head(&q->wait);
+ filep->private_data = q;
+ q->state = UACCE_Q_INIT;
+
+ return 0;
+
+out_with_mem:
+ kfree(q);
+out_with_module:
+ module_put(uacce->pdev->driver->owner);
+ return ret;
+}
+
+static int uacce_fops_release(struct inode *inode, struct file *filep)
+{
+ struct uacce_queue *q = filep->private_data;
+ struct uacce_qfile_region *qfr;
+ struct uacce_device *uacce = q->uacce;
+ bool is_to_free_region;
+ int free_pages = 0;
+ int i;
+
+ mutex_lock(&uacce_mutex);
+
+ if ((q->state == UACCE_Q_STARTED) && uacce->ops->stop_queue)
+ uacce->ops->stop_queue(q);
+
+ for (i = 0; i < UACCE_QFRT_MAX; i++) {
+ qfr = q->qfrs[i];
+ if (!qfr)
+ continue;
+
+ is_to_free_region = false;
+ uacce_queue_unmap_qfr(q, qfr);
+ if (i == UACCE_QFRT_SS) {
+ list_del(&q->list);
+ if (list_empty(&qfr->qs))
+ is_to_free_region = true;
+ } else
+ is_to_free_region = true;
+
+ if (is_to_free_region) {
+ free_pages += qfr->nr_pages;
+ uacce_destroy_region(q, qfr);
+ }
+
+ qfr = NULL;
+ }
+
+ if (current->mm == q->mm) {
+ down_write(&q->mm->mmap_sem);
+ q->mm->data_vm -= free_pages;
+ up_write(&q->mm->mmap_sem);
+ }
+
+ if (uacce->flags & UACCE_DEV_SVA)
+ iommu_sva_unbind_device(q->handle);
+
+ if ((q->state == UACCE_Q_INIT || q->state == UACCE_Q_STARTED) &&
+ uacce->ops->put_queue)
+ uacce->ops->put_queue(q);
+
+ kfree(q);
+ mutex_unlock(&uacce_mutex);
+
+ module_put(uacce->pdev->driver->owner);
+
+ return 0;
+}
+
+static int uacce_fops_mmap(struct file *filep, struct vm_area_struct *vma)
+{
+ struct uacce_queue *q = filep->private_data;
+ struct uacce_device *uacce = q->uacce;
+ struct uacce_qfile_region *qfr;
+ enum uacce_qfrt type = 0;
+ unsigned int flags = 0;
+ int ret;
+
+ if (vma->vm_pgoff < UACCE_QFRT_MAX)
+ type = vma->vm_pgoff;
+
+ vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND;
+
+ mutex_lock(&uacce_mutex);
+
+ /* fixme: if the region need no pages, we don't need to check it */
+ if (q->mm->data_vm + vma_pages(vma) >
+ rlimit(RLIMIT_DATA) >> PAGE_SHIFT) {
+ ret = -ENOMEM;
+ goto out_with_lock;
+ }
+
+ if (q->qfrs[type]) {
+ ret = -EBUSY;
+ goto out_with_lock;
+ }
+
+ switch (type) {
+ case UACCE_QFRT_MMIO:
+ flags = UACCE_QFRF_SELFMT;
+ break;
+
+ case UACCE_QFRT_SS:
+ if (q->state != UACCE_Q_STARTED) {
+ ret = -EINVAL;
+ goto out_with_lock;
+ }
+
+ if (uacce->flags & UACCE_DEV_SVA) {
+ ret = -EINVAL;
+ goto out_with_lock;
+ }
+
+ flags = UACCE_QFRF_MAP | UACCE_QFRF_MMAP;
+
+ break;
+
+ case UACCE_QFRT_DKO:
+ if (uacce->flags & UACCE_DEV_SVA) {
+ ret = -EINVAL;
+ goto out_with_lock;
+ }
+
+ flags = UACCE_QFRF_MAP | UACCE_QFRF_KMAP;
+
+ break;
+
+ case UACCE_QFRT_DUS:
+ if (uacce->flags & UACCE_DEV_SVA) {
+ flags = UACCE_QFRF_SELFMT;
+ break;
+ }
+
+ flags = UACCE_QFRF_MAP | UACCE_QFRF_MMAP;
+ break;
+
+ default:
+ WARN_ON(&uacce->dev);
+ break;
+ }
+
+ qfr = uacce_create_region(q, vma, type, flags);
+ if (IS_ERR(qfr)) {
+ ret = PTR_ERR(qfr);
+ goto out_with_lock;
+ }
+ q->qfrs[type] = qfr;
+
+ if (type == UACCE_QFRT_SS) {
+ INIT_LIST_HEAD(&qfr->qs);
+ list_add(&q->list, &q->qfrs[type]->qs);
+ }
+
+ mutex_unlock(&uacce_mutex);
+
+ if (qfr->pages)
+ q->mm->data_vm += qfr->nr_pages;
+
+ return 0;
+
+out_with_lock:
+ mutex_unlock(&uacce_mutex);
+ return ret;
+}
+
+static __poll_t uacce_fops_poll(struct file *file, poll_table *wait)
+{
+ struct uacce_queue *q = file->private_data;
+ struct uacce_device *uacce = q->uacce;
+
+ poll_wait(file, &q->wait, wait);
+ if (uacce->ops->is_q_updated && uacce->ops->is_q_updated(q))
+ return EPOLLIN | EPOLLRDNORM;
+
+ return 0;
+}
+
+static const struct file_operations uacce_fops = {
+ .owner = THIS_MODULE,
+ .open = uacce_fops_open,
+ .release = uacce_fops_release,
+ .unlocked_ioctl = uacce_fops_unl_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = uacce_fops_compat_ioctl,
+#endif
+ .mmap = uacce_fops_mmap,
+ .poll = uacce_fops_poll,
+};
+
+#define to_uacce_device(dev) container_of(dev, struct uacce_device, dev)
+
+static ssize_t id_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct uacce_device *uacce = to_uacce_device(dev);
+
+ return sprintf(buf, "%d\n", uacce->dev_id);
+}
+
+static ssize_t api_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct uacce_device *uacce = to_uacce_device(dev);
+
+ return sprintf(buf, "%s\n", uacce->api_ver);
+}
+
+static ssize_t numa_distance_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct uacce_device *uacce = to_uacce_device(dev);
+ int distance;
+
+ distance = node_distance(smp_processor_id(), uacce->pdev->numa_node);
+
+ return sprintf(buf, "%d\n", abs(distance));
+}
+
+static ssize_t node_id_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct uacce_device *uacce = to_uacce_device(dev);
+ int node_id;
+
+ node_id = dev_to_node(uacce->pdev);
+
+ return sprintf(buf, "%d\n", node_id);
+}
+
+static ssize_t flags_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct uacce_device *uacce = to_uacce_device(dev);
+
+ return sprintf(buf, "%u\n", uacce->flags);
+}
+
+static ssize_t available_instances_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct uacce_device *uacce = to_uacce_device(dev);
+ int val = 0;
+
+ if (uacce->ops->get_available_instances)
+ val = uacce->ops->get_available_instances(uacce);
+
+ return sprintf(buf, "%d\n", val);
+}
+
+static ssize_t algorithms_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct uacce_device *uacce = to_uacce_device(dev);
+
+ return sprintf(buf, "%s", uacce->algs);
+}
+
+static ssize_t qfrt_mmio_size_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct uacce_device *uacce = to_uacce_device(dev);
+
+ return sprintf(buf, "%lu\n",
+ uacce->qf_pg_size[UACCE_QFRT_MMIO] << PAGE_SHIFT);
+}
+
+static ssize_t qfrt_dko_size_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct uacce_device *uacce = to_uacce_device(dev);
+
+ return sprintf(buf, "%lu\n",
+ uacce->qf_pg_size[UACCE_QFRT_DKO] << PAGE_SHIFT);
+}
+
+static ssize_t qfrt_dus_size_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct uacce_device *uacce = to_uacce_device(dev);
+
+ return sprintf(buf, "%lu\n",
+ uacce->qf_pg_size[UACCE_QFRT_DUS] << PAGE_SHIFT);
+}
+
+static ssize_t qfrt_ss_size_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct uacce_device *uacce = to_uacce_device(dev);
+
+ return sprintf(buf, "%lu\n",
+ uacce->qf_pg_size[UACCE_QFRT_SS] << PAGE_SHIFT);
+}
+
+static DEVICE_ATTR_RO(id);
+static DEVICE_ATTR_RO(api);
+static DEVICE_ATTR_RO(numa_distance);
+static DEVICE_ATTR_RO(node_id);
+static DEVICE_ATTR_RO(flags);
+static DEVICE_ATTR_RO(available_instances);
+static DEVICE_ATTR_RO(algorithms);
+static DEVICE_ATTR_RO(qfrt_mmio_size);
+static DEVICE_ATTR_RO(qfrt_dko_size);
+static DEVICE_ATTR_RO(qfrt_dus_size);
+static DEVICE_ATTR_RO(qfrt_ss_size);
+
+static struct attribute *uacce_dev_attrs[] = {
+ &dev_attr_id.attr,
+ &dev_attr_api.attr,
+ &dev_attr_node_id.attr,
+ &dev_attr_numa_distance.attr,
+ &dev_attr_flags.attr,
+ &dev_attr_available_instances.attr,
+ &dev_attr_algorithms.attr,
+ &dev_attr_qfrt_mmio_size.attr,
+ &dev_attr_qfrt_dko_size.attr,
+ &dev_attr_qfrt_dus_size.attr,
+ &dev_attr_qfrt_ss_size.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(uacce_dev);
+
+static void uacce_release(struct device *dev)
+{
+ struct uacce_device *uacce = to_uacce_device(dev);
+
+ kfree(uacce);
+}
+
+/* Borrowed from VFIO to fix msi translation */
+static bool uacce_iommu_has_sw_msi(struct iommu_group *group,
+ phys_addr_t *base)
+{
+ struct list_head group_resv_regions;
+ struct iommu_resv_region *region, *next;
+ bool ret = false;
+
+ INIT_LIST_HEAD(&group_resv_regions);
+ iommu_get_group_resv_regions(group, &group_resv_regions);
+ list_for_each_entry(region, &group_resv_regions, list) {
+ /*
+ * The presence of any 'real' MSI regions should take
+ * precedence over the software-managed one if the
+ * IOMMU driver happens to advertise both types.
+ */
+ if (region->type == IOMMU_RESV_MSI) {
+ ret = false;
+ break;
+ }
+
+ if (region->type == IOMMU_RESV_SW_MSI) {
+ *base = region->start;
+ ret = true;
+ }
+ }
+
+ list_for_each_entry_safe(region, next, &group_resv_regions, list)
+ kfree(region);
+
+ return ret;
+}
+
+static int uacce_set_iommu_domain(struct uacce_device *uacce)
+{
+ struct iommu_domain *domain;
+ struct iommu_group *group;
+ struct device *dev = uacce->pdev;
+ bool resv_msi;
+ phys_addr_t resv_msi_base = 0;
+ int ret;
+
+ if (uacce->flags & UACCE_DEV_SVA)
+ return 0;
+
+ /* allocate and attach an unmanaged domain */
+ domain = iommu_domain_alloc(uacce->pdev->bus);
+ if (!domain) {
+ dev_err(&uacce->dev, "cannot get domain for iommu\n");
+ return -ENODEV;
+ }
+
+ ret = iommu_attach_device(domain, uacce->pdev);
+ if (ret)
+ goto err_with_domain;
+
+ if (iommu_capable(dev->bus, IOMMU_CAP_CACHE_COHERENCY))
+ uacce->prot |= IOMMU_CACHE;
+
+ group = iommu_group_get(dev);
+ if (!group) {
+ ret = -EINVAL;
+ goto err_with_domain;
+ }
+
+ resv_msi = uacce_iommu_has_sw_msi(group, &resv_msi_base);
+ iommu_group_put(group);
+
+ if (resv_msi) {
+ if (!irq_domain_check_msi_remap() &&
+ !iommu_capable(dev->bus, IOMMU_CAP_INTR_REMAP)) {
+ dev_warn(dev, "No interrupt remapping support!");
+ ret = -EPERM;
+ goto err_with_domain;
+ }
+
+ ret = iommu_get_msi_cookie(domain, resv_msi_base);
+ if (ret)
+ goto err_with_domain;
+ }
+
+ return 0;
+
+err_with_domain:
+ iommu_domain_free(domain);
+ return ret;
+}
+
+static void uacce_unset_iommu_domain(struct uacce_device *uacce)
+{
+ struct iommu_domain *domain;
+
+ if (uacce->flags & UACCE_DEV_SVA)
+ return;
+
+ domain = iommu_get_domain_for_dev(uacce->pdev);
+ if (!domain) {
+ dev_err(&uacce->dev, "bug: no domain attached to device\n");
+ return;
+ }
+
+ iommu_detach_device(domain, uacce->pdev);
+ iommu_domain_free(domain);
+}
+
+/**
+ * uacce_register - register an accelerator
+ * @parent: pointer of uacce parent device
+ * @interface: pointer of uacce_interface for register
+ */
+struct uacce_device *uacce_register(struct device *parent,
+ struct uacce_interface *interface)
+{
+ int ret;
+ struct uacce_device *uacce;
+ unsigned int flags = interface->flags;
+
+ uacce = kzalloc(sizeof(struct uacce_device), GFP_KERNEL);
+ if (!uacce)
+ return ERR_PTR(-ENOMEM);
+
+ if (flags & UACCE_DEV_SVA) {
+ ret = iommu_dev_enable_feature(parent, IOMMU_DEV_FEAT_SVA);
+ if (ret)
+ flags &= ~UACCE_DEV_SVA;
+ }
+
+ uacce->pdev = parent;
+ uacce->flags = flags;
+ uacce->ops = interface->ops;
+
+ ret = uacce_set_iommu_domain(uacce);
+ if (ret)
+ goto err_free;
+
+ mutex_lock(&uacce_mutex);
+
+ ret = idr_alloc(&uacce_idr, uacce, 0, 0, GFP_KERNEL);
+ if (ret < 0)
+ goto err_with_lock;
+
+ uacce->cdev = cdev_alloc();
+ uacce->cdev->ops = &uacce_fops;
+ uacce->dev_id = ret;
+ uacce->cdev->owner = THIS_MODULE;
+ device_initialize(&uacce->dev);
+ uacce->dev.devt = MKDEV(MAJOR(uacce_devt), uacce->dev_id);
+ uacce->dev.class = uacce_class;
+ uacce->dev.groups = uacce_dev_groups;
+ uacce->dev.parent = uacce->pdev;
+ uacce->dev.release = uacce_release;
+ dev_set_name(&uacce->dev, "%s-%d", interface->name, uacce->dev_id);
+ ret = cdev_device_add(uacce->cdev, &uacce->dev);
+ if (ret)
+ goto err_with_idr;
+
+ mutex_unlock(&uacce_mutex);
+
+ return uacce;
+
+err_with_idr:
+ idr_remove(&uacce_idr, uacce->dev_id);
+err_with_lock:
+ mutex_unlock(&uacce_mutex);
+ uacce_unset_iommu_domain(uacce);
+err_free:
+ if (flags & UACCE_DEV_SVA)
+ iommu_dev_disable_feature(uacce->pdev, IOMMU_DEV_FEAT_SVA);
+ kfree(uacce);
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(uacce_register);
+
+/**
+ * uacce_unregister - unregisters an accelerator
+ * @uacce: the accelerator to unregister
+ */
+void uacce_unregister(struct uacce_device *uacce)
+{
+ if (uacce == NULL)
+ return;
+
+ mutex_lock(&uacce_mutex);
+
+ if (uacce->flags & UACCE_DEV_SVA)
+ iommu_dev_disable_feature(uacce->pdev, IOMMU_DEV_FEAT_SVA);
+
+ uacce_unset_iommu_domain(uacce);
+ cdev_device_del(uacce->cdev, &uacce->dev);
+ idr_remove(&uacce_idr, uacce->dev_id);
+ put_device(&uacce->dev);
+
+ mutex_unlock(&uacce_mutex);
+}
+EXPORT_SYMBOL_GPL(uacce_unregister);
+
+static int __init uacce_init(void)
+{
+ int ret;
+
+ uacce_class = class_create(THIS_MODULE, UACCE_NAME);
+ if (IS_ERR(uacce_class)) {
+ ret = PTR_ERR(uacce_class);
+ goto err;
+ }
+
+ ret = alloc_chrdev_region(&uacce_devt, 0, MINORMASK, UACCE_NAME);
+ if (ret)
+ goto err_with_class;
+
+ return 0;
+
+err_with_class:
+ class_destroy(uacce_class);
+err:
+ return ret;
+}
+
+static __exit void uacce_exit(void)
+{
+ unregister_chrdev_region(uacce_devt, MINORMASK);
+ class_destroy(uacce_class);
+ idr_destroy(&uacce_idr);
+}
+
+subsys_initcall(uacce_init);
+module_exit(uacce_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Hisilicon Tech. Co., Ltd.");
+MODULE_DESCRIPTION("Accelerator interface for Userland applications");
diff --git a/include/linux/uacce.h b/include/linux/uacce.h
new file mode 100644
index 0000000..8ce0640
--- /dev/null
+++ b/include/linux/uacce.h
@@ -0,0 +1,168 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _LINUX_UACCE_H
+#define _LINUX_UACCE_H
+
+#include <linux/cdev.h>
+#include <uapi/misc/uacce/uacce.h>
+
+#define UACCE_NAME "uacce"
+
+struct uacce_queue;
+struct uacce_device;
+
+/* uacce queue file flag, requires different operation */
+#define UACCE_QFRF_MAP BIT(0) /* map to current queue */
+#define UACCE_QFRF_MMAP BIT(1) /* map to user space */
+#define UACCE_QFRF_KMAP BIT(2) /* map to kernel space */
+#define UACCE_QFRF_DMA BIT(3) /* use dma api for the region */
+#define UACCE_QFRF_SELFMT BIT(4) /* self maintained qfr */
+
+/**
+ * struct uacce_qfile_region - structure of queue file region
+ * @type: type of the qfr
+ * @iova: iova share between user and device space
+ * @pages: pages pointer of the qfr memory
+ * @nr_pages: page numbers of the qfr memory
+ * @prot: qfr protection flag
+ * @flags: flags of qfr
+ * @qs: list sharing the same region, for ss region
+ * @kaddr: kernel addr of the qfr
+ * @dma: dma address, if created by dma api
+ */
+struct uacce_qfile_region {
+ enum uacce_qfrt type;
+ unsigned long iova;
+ struct page **pages;
+ u32 nr_pages;
+ u32 prot;
+ u32 flags;
+ struct list_head qs;
+ void *kaddr;
+ dma_addr_t dma;
+};
+
+/**
+ * struct uacce_ops - uacce device operations
+ * @get_available_instances: get available instances left of the device
+ * @get_queue: get a queue from the device
+ * @put_queue: free a queue to the device
+ * @start_queue: make the queue start work after get_queue
+ * @stop_queue: make the queue stop work before put_queue
+ * @is_q_updated: check whether the task is finished
+ * @mask_notify: mask the task irq of queue
+ * @mmap: mmap addresses of queue to user space
+ * @reset: reset the uacce device
+ * @reset_queue: reset the queue
+ * @ioctl: ioctl for user space users of the queue
+ */
+struct uacce_ops {
+ int (*get_available_instances)(struct uacce_device *uacce);
+ int (*get_queue)(struct uacce_device *uacce, unsigned long arg,
+ struct uacce_queue *q);
+ void (*put_queue)(struct uacce_queue *q);
+ int (*start_queue)(struct uacce_queue *q);
+ void (*stop_queue)(struct uacce_queue *q);
+ int (*is_q_updated)(struct uacce_queue *q);
+ void (*mask_notify)(struct uacce_queue *q, int event_mask);
+ int (*mmap)(struct uacce_queue *q, struct vm_area_struct *vma,
+ struct uacce_qfile_region *qfr);
+ int (*reset)(struct uacce_device *uacce);
+ int (*reset_queue)(struct uacce_queue *q);
+ long (*ioctl)(struct uacce_queue *q, unsigned int cmd,
+ unsigned long arg);
+};
+
+/**
+ * struct uacce_interface
+ * @name: the uacce device name. Will show up in sysfs
+ * @flags: uacce device attributes
+ * @ops: pointer to the struct uacce_ops
+ *
+ * This structure is used for the uacce_register()
+ */
+struct uacce_interface {
+ char name[32];
+ unsigned int flags;
+ struct uacce_ops *ops;
+};
+
+enum uacce_q_state {
+ UACCE_Q_INIT,
+ UACCE_Q_STARTED,
+ UACCE_Q_ZOMBIE,
+};
+
+/**
+ * struct uacce_queue
+ * @uacce: pointer to uacce
+ * @priv: private pointer
+ * @wait: wait queue head
+ * @pasid: pasid of the queue
+ * @handle: iommu_sva handle return from iommu_sva_bind_device
+ * @list: share list for qfr->qs
+ * @mm: current->mm
+ * @qfrs: pointer of qfr regions
+ * @state: queue state machine
+ */
+struct uacce_queue {
+ struct uacce_device *uacce;
+ void *priv;
+ wait_queue_head_t wait;
+ int pasid;
+ struct iommu_sva *handle;
+ struct list_head list;
+ struct mm_struct *mm;
+ struct uacce_qfile_region *qfrs[UACCE_QFRT_MAX];
+ enum uacce_q_state state;
+};
+
+/**
+ * struct uacce_device
+ * @algs: supported algorithms
+ * @api_ver: api version
+ * @qf_pg_size: page size of the queue file regions
+ * @ops: pointer to the struct uacce_ops
+ * @pdev: pointer to the parent device
+ * @is_vf: whether virtual function
+ * @flags: uacce attributes
+ * @dev_id: id of the uacce device
+ * @prot: uacce protection flag
+ * @cdev: cdev of the uacce
+ * @dev: dev of the uacce
+ * @priv: private pointer of the uacce
+ */
+struct uacce_device {
+ const char *algs;
+ const char *api_ver;
+ unsigned long qf_pg_size[UACCE_QFRT_MAX];
+ struct uacce_ops *ops;
+ struct device *pdev;
+ bool is_vf;
+ u32 flags;
+ u32 dev_id;
+ u32 prot;
+ struct cdev *cdev;
+ struct device dev;
+ void *priv;
+};
+
+#if IS_ENABLED(CONFIG_UACCE)
+
+struct uacce_device *uacce_register(struct device *parent,
+ struct uacce_interface *interface);
+void uacce_unregister(struct uacce_device *uacce);
+
+#else /* CONFIG_UACCE */
+
+static inline
+struct uacce_device *uacce_register(struct device *parent,
+ struct uacce_interface *interface)
+{
+ return ERR_PTR(-ENODEV);
+}
+
+static inline void uacce_unregister(struct uacce_device *uacce) {}
+
+#endif /* CONFIG_UACCE */
+
+#endif /* _LINUX_UACCE_H */
diff --git a/include/uapi/misc/uacce/uacce.h b/include/uapi/misc/uacce/uacce.h
new file mode 100644
index 0000000..c859668
--- /dev/null
+++ b/include/uapi/misc/uacce/uacce.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _UAPIUUACCE_H
+#define _UAPIUUACCE_H
+
+#include <linux/types.h>
+#include <linux/ioctl.h>
+
+#define UACCE_CMD_SHARE_SVAS _IO('W', 0)
+#define UACCE_CMD_START _IO('W', 1)
+#define UACCE_CMD_PUT_Q _IO('W', 2)
+
+/**
+ * enum uacce_dev_flag: Device flags:
+ * @UACCE_DEV_SHARE_DOMAIN: no PASID, can share sva for one process
+ * @UACCE_DEV_SVA: Shared Virtual Addresses
+ * Support PASID
+ * Support device page fault (pcie device) or
+ * smmu stall (platform device)
+ */
+enum uacce_dev_flag {
+ UACCE_DEV_SHARE_DOMAIN = 0x0,
+ UACCE_DEV_SVA = 0x1,
+};
+
+/**
+ * enum uacce_qfrt: qfrt type
+ * @UACCE_QFRT_MMIO: device mmio region
+ * @UACCE_QFRT_DKO: device kernel-only region
+ * @UACCE_QFRT_DUS: device user share region
+ * @UACCE_QFRT_SS: static shared memory region
+ * @UACCE_QFRT_MAX: indicate the boundary
+ */
+enum uacce_qfrt {
+ UACCE_QFRT_MMIO = 0,
+ UACCE_QFRT_DKO = 1,
+ UACCE_QFRT_DUS = 2,
+ UACCE_QFRT_SS = 3,
+ UACCE_QFRT_MAX = 16,
+};
+
+#endif
--
2.7.4
Hi,
I have a few comments on the overall design and some implementation
details below.
Could you also Cc [email protected] on your next posting?
I'm sure some subscribers would be interested and I don't think many
people know about linux-accelerators yet.
On Wed, Oct 16, 2019 at 04:34:32PM +0800, Zhangfei Gao wrote:
> diff --git a/Documentation/ABI/testing/sysfs-driver-uacce b/Documentation/ABI/testing/sysfs-driver-uacce
> new file mode 100644
> index 0000000..e48333c
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-driver-uacce
> @@ -0,0 +1,65 @@
> +What: /sys/class/uacce/hisi_zip-<n>/id
Should probably be /sys/class/uacce/<dev_name>/ if we want the API to be
used by other drivers.
[...]
> +static int uacce_queue_map_qfr(struct uacce_queue *q,
> + struct uacce_qfile_region *qfr)
> +{
> + struct device *dev = q->uacce->pdev;
> + struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
> + int i, j, ret;
> +
> + if (!(qfr->flags & UACCE_QFRF_MAP) || (qfr->flags & UACCE_QFRF_DMA))
> + return 0;
> +
> + if (!domain)
> + return -ENODEV;
> +
> + for (i = 0; i < qfr->nr_pages; i++) {
> + ret = iommu_map(domain, qfr->iova + i * PAGE_SIZE,
> + page_to_phys(qfr->pages[i]),
> + PAGE_SIZE, qfr->prot | q->uacce->prot);
> + if (ret)
> + goto err_with_map_pages;
> +
> + get_page(qfr->pages[i]);
I guess we need this reference when coming from UACCE_CMD_SHARE_SVAS?
Otherwise we should already get one from alloc_page().
[...]
> +static int uacce_qfr_alloc_pages(struct uacce_qfile_region *qfr)
> +{
> + int i, j;
> +
> + qfr->pages = kcalloc(qfr->nr_pages, sizeof(*qfr->pages), GFP_ATOMIC);
Why GFP_ATOMIC and not GFP_KERNEL? GFP_ATOMIC is used all over this file
but there doesn't seem to be any non-sleepable context.
> + if (!qfr->pages)
> + return -ENOMEM;
> +
> + for (i = 0; i < qfr->nr_pages; i++) {
> + qfr->pages[i] = alloc_page(GFP_ATOMIC | __GFP_ZERO);
Is it worth copying __iommu_dma_alloc_pages() here - using
alloc_pages_node() to allocate memory close to the device and to allocate
compound pages if possible?
Also, do we need GFP_USER here?
More generally, it would be nice to use the DMA API when SVA isn't
supported, instead of manually allocating and mapping memory with
iommu_map(). Do we only handcraft these functions in order to have VA ==
IOVA? On its own it doesn't seem like a strong enough reason to avoid the
DMA API.
SVA simplifies DMA memory management and enables core mm features for DMA
such as demand paging. VA == IOVA is just a natural consequence. But in
the !SVA mode, the userspace library does need to create DMA mappings
itself. So, since it has special cases for !SVA, it could easily get the
IOVA of a DMA buffer from the kernel using another ioctl.
[...]
> +static struct uacce_qfile_region *
> +uacce_create_region(struct uacce_queue *q, struct vm_area_struct *vma,
> + enum uacce_qfrt type, unsigned int flags)
> +{
> + struct uacce_qfile_region *qfr;
> + struct uacce_device *uacce = q->uacce;
> + unsigned long vm_pgoff;
> + int ret = -ENOMEM;
> +
> + qfr = kzalloc(sizeof(*qfr), GFP_ATOMIC);
> + if (!qfr)
> + return ERR_PTR(-ENOMEM);
> +
> + qfr->type = type;
> + qfr->flags = flags;
> + qfr->iova = vma->vm_start;
> + qfr->nr_pages = vma_pages(vma);
> +
> + if (vma->vm_flags & VM_READ)
> + qfr->prot |= IOMMU_READ;
> +
> + if (vma->vm_flags & VM_WRITE)
> + qfr->prot |= IOMMU_WRITE;
> +
> + if (flags & UACCE_QFRF_SELFMT) {
> + if (!uacce->ops->mmap) {
> + ret = -EINVAL;
> + goto err_with_qfr;
> + }
> +
> + ret = uacce->ops->mmap(q, vma, qfr);
> + if (ret)
> + goto err_with_qfr;
> + return qfr;
> + }
I wish the SVA and !SVA paths were less interleaved. Both models are
fundamentally different:
* Without SVA you cannot share the device between multiple processes. All
DMA mappings are in the "main", non-PASID address space of the device.
Note that process isolation without SVA could be achieved with the
auxiliary domains IOMMU API (introduced primarily for vfio-mdev) but
this is not the model chosen here.
* With SVA you can share the device between multiple processes. But if the
process can somehow program its portion of the device to access the main
address space, you loose isolation. Only the kernel must be able to
program and access the main address space.
When interleaving both code paths it's easy to make a mistake and loose
this isolation. Although I think this code is correct, it took me some
time to understand that we never end up calling dma_alloc or iommu_map
when using SVA. Might be worth at least adding a check that if
UACCE_DEV_SVA, then we never end up in the bottom part of this function.
> +
> + /* allocate memory */
> + if (flags & UACCE_QFRF_DMA) {
At the moment UACCE_QFRF_DMA is never set, so there is a lot of unused and
possibly untested code in this file. I think it would be simpler to choose
between either DMA API or unmanaged IOMMU domains and stick with it. As
said before, I'd prefer DMA API.
> + qfr->kaddr = dma_alloc_coherent(uacce->pdev,
> + qfr->nr_pages << PAGE_SHIFT,
> + &qfr->dma, GFP_KERNEL);
> + if (!qfr->kaddr) {
> + ret = -ENOMEM;
> + goto err_with_qfr;
> + }
> + } else {
> + ret = uacce_qfr_alloc_pages(qfr);
> + if (ret)
> + goto err_with_qfr;
> + }
> +
> + /* map to device */
> + ret = uacce_queue_map_qfr(q, qfr);
Worth moving into the else above.
[...]
> +static long uacce_cmd_share_qfr(struct uacce_queue *tgt, int fd)
> +{
> + struct file *filep;
> + struct uacce_queue *src;
> + int ret = -EINVAL;
> +
> + mutex_lock(&uacce_mutex);
> +
> + if (tgt->state != UACCE_Q_STARTED)
> + goto out_with_lock;
> +
> + filep = fget(fd);
> + if (!filep)
> + goto out_with_lock;
> +
> + if (filep->f_op != &uacce_fops)
> + goto out_with_fd;
> +
> + src = filep->private_data;
> + if (!src)
> + goto out_with_fd;
> +
> + if (tgt->uacce->flags & UACCE_DEV_SVA)
> + goto out_with_fd;
> +
> + if (!src->qfrs[UACCE_QFRT_SS] || tgt->qfrs[UACCE_QFRT_SS])
> + goto out_with_fd;
> +
> + ret = uacce_queue_map_qfr(tgt, src->qfrs[UACCE_QFRT_SS]);
I don't understand what this ioctl does. The function duplicates the
static mappings from one queue to another, right? But static mappings are
a !SVA thing and currently on !SVA a single queue can be opened at a time.
In addition, unless the two queues belong to different devices, they would
share the same IOMMU domain and the mappings would already exist, so you
don't need to call uacce_queue_map_qfr() again.
[...]
> +static long uacce_put_queue(struct uacce_queue *q)
> +{
> + struct uacce_device *uacce = q->uacce;
> +
> + mutex_lock(&uacce_mutex);
> +
> + if ((q->state == UACCE_Q_STARTED) && uacce->ops->stop_queue)
> + uacce->ops->stop_queue(q);
> +
> + if ((q->state == UACCE_Q_INIT || q->state == UACCE_Q_STARTED) &&
> + uacce->ops->put_queue)
> + uacce->ops->put_queue(q);
> +
> + q->state = UACCE_Q_ZOMBIE;
Since the PUT_Q ioctl makes the queue unrecoverable, why should userspace
invoke it instead of immediately calling close()?
[...]
> +static int uacce_dev_open_check(struct uacce_device *uacce)
> +{
> + if (uacce->flags & UACCE_DEV_SVA)
> + return 0;
> +
> + /*
> + * The device can be opened once if it does not support pasid
> + */
> + if (kref_read(&uacce->cdev->kobj.kref) > 2)
Why 2? It doesn't feel right to access the cdev internals for this, could
we just have a ref uacce->opened for this purpose?
> + return -EBUSY;
> +
> + return 0;
> +}
> +
> +static int uacce_fops_open(struct inode *inode, struct file *filep)
> +{
> + struct uacce_queue *q;
> + struct iommu_sva *handle = NULL;
> + struct uacce_device *uacce;
> + int ret;
> + int pasid = 0;
> +
> + uacce = idr_find(&uacce_idr, iminor(inode));
> + if (!uacce)
> + return -ENODEV;
> +
> + if (!try_module_get(uacce->pdev->driver->owner))
> + return -ENODEV;
> +
> + ret = uacce_dev_open_check(uacce);
> + if (ret)
> + goto out_with_module;
> +
> + if (uacce->flags & UACCE_DEV_SVA) {
> + handle = iommu_sva_bind_device(uacce->pdev, current->mm, NULL);
> + if (IS_ERR(handle))
> + goto out_with_module;
> + pasid = iommu_sva_get_pasid(handle);
We need to register an mm_exit callback. Once we return, userspace will
start running jobs on the accelerator. If the process is killed while the
accelerator is running, the mm_exit callback tells the device driver to
stop using this PASID (stop_queue()), so that it can be reallocated for
another process.
Implementing this with the right locking and ordering can be tricky. I'll
try to implement the callback and test it on the device this week.
[...]
> +static int uacce_fops_mmap(struct file *filep, struct vm_area_struct *vma)
> +{
> + struct uacce_queue *q = filep->private_data;
> + struct uacce_device *uacce = q->uacce;
> + struct uacce_qfile_region *qfr;
> + enum uacce_qfrt type = 0;
> + unsigned int flags = 0;
> + int ret;
> +
> + if (vma->vm_pgoff < UACCE_QFRT_MAX)
> + type = vma->vm_pgoff;
> +
> + vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND;
> +
> + mutex_lock(&uacce_mutex);
> +
> + /* fixme: if the region need no pages, we don't need to check it */
> + if (q->mm->data_vm + vma_pages(vma) >
> + rlimit(RLIMIT_DATA) >> PAGE_SHIFT) {
Doesn't may_expand_vm() do the job already?
> + ret = -ENOMEM;
> + goto out_with_lock;
> + }
> +
> + if (q->qfrs[type]) {
> + ret = -EBUSY;
> + goto out_with_lock;
> + }
> +
> + switch (type) {
> + case UACCE_QFRT_MMIO:
> + flags = UACCE_QFRF_SELFMT;
> + break;
> +
> + case UACCE_QFRT_SS:
> + if (q->state != UACCE_Q_STARTED) {
> + ret = -EINVAL;
> + goto out_with_lock;
> + }
> +
> + if (uacce->flags & UACCE_DEV_SVA) {
> + ret = -EINVAL;
> + goto out_with_lock;
> + }
> +
> + flags = UACCE_QFRF_MAP | UACCE_QFRF_MMAP;
> +
> + break;
> +
> + case UACCE_QFRT_DKO:
> + if (uacce->flags & UACCE_DEV_SVA) {
> + ret = -EINVAL;
> + goto out_with_lock;
> + }
> +
> + flags = UACCE_QFRF_MAP | UACCE_QFRF_KMAP;
> +
> + break;
> +
> + case UACCE_QFRT_DUS:
> + if (uacce->flags & UACCE_DEV_SVA) {
> + flags = UACCE_QFRF_SELFMT;
> + break;
> + }
> +
> + flags = UACCE_QFRF_MAP | UACCE_QFRF_MMAP;
> + break;
> +
> + default:
> + WARN_ON(&uacce->dev);
> + break;
> + }
> +
> + qfr = uacce_create_region(q, vma, type, flags);
Don't we need to setup a a vma->vm_ops->close callback, to remove this
region on munmap()?
> + if (IS_ERR(qfr)) {
> + ret = PTR_ERR(qfr);
> + goto out_with_lock;
> + }
> + q->qfrs[type] = qfr;
> +
> + if (type == UACCE_QFRT_SS) {
> + INIT_LIST_HEAD(&qfr->qs);
> + list_add(&q->list, &q->qfrs[type]->qs);
> + }
> +
> + mutex_unlock(&uacce_mutex);
> +
> + if (qfr->pages)
> + q->mm->data_vm += qfr->nr_pages;
This too should be done by the core already.
[...]
> +/* Borrowed from VFIO to fix msi translation */
> +static bool uacce_iommu_has_sw_msi(struct iommu_group *group,
Sharing the same functions would be nicer.
[...]
> +struct uacce_device *uacce_register(struct device *parent,
> + struct uacce_interface *interface)
> +{
> + int ret;
> + struct uacce_device *uacce;
> + unsigned int flags = interface->flags;
> +
> + uacce = kzalloc(sizeof(struct uacce_device), GFP_KERNEL);
> + if (!uacce)
> + return ERR_PTR(-ENOMEM);
> +
> + if (flags & UACCE_DEV_SVA) {
> + ret = iommu_dev_enable_feature(parent, IOMMU_DEV_FEAT_SVA);
> + if (ret)
> + flags &= ~UACCE_DEV_SVA;
> + }
> +
> + uacce->pdev = parent;
> + uacce->flags = flags;
> + uacce->ops = interface->ops;
> +
> + ret = uacce_set_iommu_domain(uacce);
> + if (ret)
> + goto err_free;
> +
> + mutex_lock(&uacce_mutex);
> +
> + ret = idr_alloc(&uacce_idr, uacce, 0, 0, GFP_KERNEL);
> + if (ret < 0)
> + goto err_with_lock;
> +
> + uacce->cdev = cdev_alloc();
Need to check the return value.
> + uacce->cdev->ops = &uacce_fops;
> + uacce->dev_id = ret;
> + uacce->cdev->owner = THIS_MODULE;
> + device_initialize(&uacce->dev);
> + uacce->dev.devt = MKDEV(MAJOR(uacce_devt), uacce->dev_id);
> + uacce->dev.class = uacce_class;
> + uacce->dev.groups = uacce_dev_groups;
> + uacce->dev.parent = uacce->pdev;
> + uacce->dev.release = uacce_release;
> + dev_set_name(&uacce->dev, "%s-%d", interface->name, uacce->dev_id);
> + ret = cdev_device_add(uacce->cdev, &uacce->dev);
> + if (ret)
> + goto err_with_idr;
> +
> + mutex_unlock(&uacce_mutex);
We published the new device into /dev/ and /sys/ even though the uacce
structure has yet to be completed by the caller (for example qf_pg_size,
api_ver, etc). Maybe we can add an initializer to uacce_ops so we can
publish a complete structure?
> +
> + return uacce;
> +
> +err_with_idr:
> + idr_remove(&uacce_idr, uacce->dev_id);
> +err_with_lock:
> + mutex_unlock(&uacce_mutex);
> + uacce_unset_iommu_domain(uacce);
> +err_free:
> + if (flags & UACCE_DEV_SVA)
> + iommu_dev_disable_feature(uacce->pdev, IOMMU_DEV_FEAT_SVA);
> + kfree(uacce);
> + return ERR_PTR(ret);
> +}
> +EXPORT_SYMBOL_GPL(uacce_register);
> +
> +/**
> + * uacce_unregister - unregisters an accelerator
> + * @uacce: the accelerator to unregister
> + */
> +void uacce_unregister(struct uacce_device *uacce)
> +{
> + if (uacce == NULL)
> + return;
> +
> + mutex_lock(&uacce_mutex);
Are we certain that no open queue remains?
> +
> + if (uacce->flags & UACCE_DEV_SVA)
> + iommu_dev_disable_feature(uacce->pdev, IOMMU_DEV_FEAT_SVA);
> +
> + uacce_unset_iommu_domain(uacce);
> + cdev_device_del(uacce->cdev, &uacce->dev);
> + idr_remove(&uacce_idr, uacce->dev_id);
> + put_device(&uacce->dev);
> +
> + mutex_unlock(&uacce_mutex);
> +}
> +EXPORT_SYMBOL_GPL(uacce_unregister);
> diff --git a/include/uapi/misc/uacce/uacce.h b/include/uapi/misc/uacce/uacce.h
> new file mode 100644
> index 0000000..c859668
> --- /dev/null
> +++ b/include/uapi/misc/uacce/uacce.h
> @@ -0,0 +1,41 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
Needs to be
/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
Otherwise headers_install.sh complains on v5.4 (same for the qm UAPI in
patch 3)
> +#ifndef _UAPIUUACCE_H
> +#define _UAPIUUACCE_H
> +
> +#include <linux/types.h>
> +#include <linux/ioctl.h>
> +
> +#define UACCE_CMD_SHARE_SVAS _IO('W', 0)
> +#define UACCE_CMD_START _IO('W', 1)
> +#define UACCE_CMD_PUT_Q _IO('W', 2)
These must be documented.
> +
> +/**
> + * enum uacce_dev_flag: Device flags:
> + * @UACCE_DEV_SHARE_DOMAIN: no PASID, can share sva for one process
> + * @UACCE_DEV_SVA: Shared Virtual Addresses
> + * Support PASID
> + * Support device page fault (pcie device) or
> + * smmu stall (platform device)
Both stall and PRI are device page faults, so this could say "Support
device page faults (PCI PRI or SMMU Stall)".
> + */
> +enum uacce_dev_flag {
> + UACCE_DEV_SHARE_DOMAIN = 0x0,
> + UACCE_DEV_SVA = 0x1,
> +};
This is a bitmap so UACCE_DEV_SHARE_DOMAIN will loose its meaning when
adding a new flag. There will be:
UACCE_DEV_SVA = 1 << 0,
UACCE_DEV_NEWFEATURE = 1 << 1,
Then a value of zero will simply mean "no special feature". I think we
could simply remove UACCE_DEV_SHARE_DOMAIN now, it's not used.
Thanks,
Jean
On Fri, Oct 25, 2019 at 10:28:30AM +0800, [email protected] wrote:
> > Something else I noticed is uacce_idr isn't currently protected. The IDR
> > API expected the caller to use its own locking scheme. You could replace
> > it with an xarray, which I think is preferred to IDR now and provides a
> > xa_lock.
> Currently idr_alloc and idr_remove are simply protected by uacce_mutex,
Ah right, but idr_find() also needs to be protected?
> Will check xarray, looks it is more complicated then idr.
Having tried both, it can easily replace idr. For uacce I think it could
be something like (locking included):
static DEFINE_XARRAY_ALLOC(uacce_xa);
uacce = xa_load(&uacce_xa, iminor(inode));
ret = xa_alloc(&uacce_xa, &uacce->dev_id, uacce, xa_limit_32b,
GFP_KERNEL);
xa_erase(&uacce_xa, uacce->dev_id);
Thanks,
Jean