On Fri, 2020-03-20 at 23:18 +1100, Daniel Axtens wrote: > Haren Myneni <ha...@linux.ibm.com> writes: > > > On power9, userspace can send GZIP compression requests directly to NX > > once kernel establishes NX channel / window with VAS. This patch provides > > user space API which allows user space to establish channel using open > > VAS_TX_WIN_OPEN ioctl, mmap and close operations. > > > > Each window corresponds to file descriptor and application can open > > multiple windows. After the window is opened, VAS_TX_WIN_OPEN icoctl to > > open a window on specific VAS instance, mmap() system call to map > > the hardware address of engine's request queue into the application's > > virtual address space. > > > > Then the application can then submit one or more requests to the the > > engine by using the copy/paste instructions and pasting the CRBs to > > the virtual address (aka paste_address) returned by mmap(). > > > > Only NX GZIP coprocessor type is supported right now and allow GZIP > > engine access via /dev/crypto/nx-gzip device node. > > > > Signed-off-by: Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com> > > Signed-off-by: Haren Myneni <ha...@linux.ibm.com> > > --- > > arch/powerpc/include/asm/vas.h | 11 ++ > > arch/powerpc/platforms/powernv/Makefile | 2 +- > > arch/powerpc/platforms/powernv/vas-api.c | 290 > > ++++++++++++++++++++++++++++ > > arch/powerpc/platforms/powernv/vas-window.c | 6 +- > > arch/powerpc/platforms/powernv/vas.h | 2 + > > 5 files changed, 307 insertions(+), 4 deletions(-) > > create mode 100644 arch/powerpc/platforms/powernv/vas-api.c > > > > diff --git a/arch/powerpc/include/asm/vas.h b/arch/powerpc/include/asm/vas.h > > index f93e6b0..e064953 100644 > > --- a/arch/powerpc/include/asm/vas.h > > +++ b/arch/powerpc/include/asm/vas.h > > @@ -163,4 +163,15 @@ struct vas_window *vas_tx_win_open(int vasid, enum > > vas_cop_type cop, > > */ > > int vas_paste_crb(struct vas_window *win, int offset, bool re); > > > > +/* > > + * Register / unregister coprocessor type to VAS API which will be exported > > + * to user space. Applications can use this API to open / close window > > + * which can be used to send / receive requests directly to cooprcessor. > > + * > > + * Only NX GZIP coprocessor type is supported now, but this API can be > > + * used for others in future. > > + */ > > +int vas_register_coproc_api(struct module *mod); > > +void vas_unregister_coproc_api(void); > > + > > #endif /* __ASM_POWERPC_VAS_H */ > > diff --git a/arch/powerpc/platforms/powernv/Makefile > > b/arch/powerpc/platforms/powernv/Makefile > > index 395789f..fe3f0fb 100644 > > --- a/arch/powerpc/platforms/powernv/Makefile > > +++ b/arch/powerpc/platforms/powernv/Makefile > > @@ -17,7 +17,7 @@ obj-$(CONFIG_MEMORY_FAILURE) += opal-memory-errors.o > > obj-$(CONFIG_OPAL_PRD) += opal-prd.o > > obj-$(CONFIG_PERF_EVENTS) += opal-imc.o > > obj-$(CONFIG_PPC_MEMTRACE) += memtrace.o > > -obj-$(CONFIG_PPC_VAS) += vas.o vas-window.o vas-debug.o vas-fault.o > > +obj-$(CONFIG_PPC_VAS) += vas.o vas-window.o vas-debug.o vas-fault.o > > vas-api.o > > obj-$(CONFIG_OCXL_BASE) += ocxl.o > > obj-$(CONFIG_SCOM_DEBUGFS) += opal-xscom.o > > obj-$(CONFIG_PPC_SECURE_BOOT) += opal-secvar.o > > diff --git a/arch/powerpc/platforms/powernv/vas-api.c > > b/arch/powerpc/platforms/powernv/vas-api.c > > new file mode 100644 > > index 0000000..3473a4a > > --- /dev/null > > +++ b/arch/powerpc/platforms/powernv/vas-api.c > > @@ -0,0 +1,290 @@ > > +// SPDX-License-Identifier: GPL-2.0-or-later > > +/* > > + * VAS user space API for its accelerators (Only NX-GZIP is supported now) > > + * Copyright (C) 2019 Haren Myneni, IBM Corp > > + */ > > + > > +#include <linux/kernel.h> > > +#include <linux/device.h> > > +#include <linux/cdev.h> > > +#include <linux/fs.h> > > +#include <linux/slab.h> > > +#include <linux/uaccess.h> > > +#include <asm/vas.h> > > +#include <uapi/asm/vas-api.h> > > +#include "vas.h" > > + > > +/* > > + * The driver creates the device node that can be used as follows: > > + * For NX-GZIP > > + * > > + * fd = open("/dev/crypto/nx-gzip", O_RDWR); > > + * rc = ioctl(fd, VAS_TX_WIN_OPEN, &attr); > > + * paste_addr = mmap(NULL, PAGE_SIZE, prot, MAP_SHARED, fd, 0ULL). > > + * vas_copy(&crb, 0, 1); > > + * vas_paste(paste_addr, 0, 1); > > + * close(fd) or exit process to close window. > > + * > > + * where "vas_copy" and "vas_paste" are defined in copy-paste.h. > > + * copy/paste returns to the user space directly. So refer NX hardware > > + * documententation for excat copy/paste usage and completion / error > > + * conditions. > > + */ > > + > > +static char *coproc_dev_name = "nx-gzip"; > > +static atomic_t coproc_instid = ATOMIC_INIT(0); > > + > > +/* > > + * Wrapper object for the nx-gzip device - there is just one instance of > > + * this node for the whole system. > > + */ > > +static struct coproc_dev { > > + struct cdev cdev; > > + struct device *device; > > + char *name; > > + dev_t devt; > > + struct class *class; > > +} coproc_device; > > + > > +/* > > + * One instance per open of a nx-gzip device. Each coproc_instance is > > + * associated with a VAS window after the caller issues > > + * VAS_GZIP_TX_WIN_OPEN ioctl. > > + */ > > +struct coproc_instance { > > + int id; > > + struct vas_window *txwin; > > +}; > > + > > +static char *coproc_devnode(struct device *dev, umode_t *mode) > > +{ > > + return kasprintf(GFP_KERNEL, "crypto/%s", dev_name(dev)); > > +} > > + > > +static int coproc_open(struct inode *inode, struct file *fp) > > +{ > > + struct coproc_instance *instance; > > + > > + instance = kzalloc(sizeof(*instance), GFP_KERNEL); > > + if (!instance) > > + return -ENOMEM; > > + > > + instance->id = atomic_inc_return(&coproc_instid); > > I don't understand what this instance->id field does - I can't find any > other uses of it in these series. > > I'm also not sure that this gives you a unique id - you increment it > here and decrement it in coproc_release, but I'm not sure what prevents > the same ID being given to multiple instances, e.g. the following > sequence > > coproc_open(inode, file A) -> instance with id 0, coproc_instid = 1 > coproc_open(inode, file B) -> instance with id 1, coproc_instid = 2 > coproc_release(inode, file A) -> release id 0, coproc_instid = 1 > coproc_open(inode, file C) -> instance with id 1, coproc_instid = 2 > > File B and C both have ID = 1, unless I'm misunderstanding something.
Thanks for your comments. coproc_instid is not needed. Sorry My mistake, it was added in prototype code, but forgot to remove. Added to determine how many windows are active, but not needed now. I will repost the patch with this change. > > > + > > + fp->private_data = instance; > > + return 0; > > +} > > + > > +static int coproc_ioc_tx_win_open(struct file *fp, unsigned long arg) > > +{ > > + int rc, vasid; > > + struct vas_tx_win_attr txattr; > > + struct vas_tx_win_open_attr uattr; > > + void __user *uptr = (void __user *)arg; > > + struct vas_window *txwin; > > + struct coproc_instance *nxti = fp->private_data; > > + > > + if (!nxti) > > + return -EINVAL; > > + > > + /* > > + * One window for file descriptor > > + */ > > + if (nxti->txwin) > > + return -EEXIST; > > + > > + rc = copy_from_user(&uattr, uptr, sizeof(uattr)); > > + if (rc) { > > + pr_err("%s(): copy_from_user() returns %d\n", __func__, rc); > > + return -EFAULT; > > + } > > + > > + if (uattr.version != 1) { > > + pr_err("Invalid version\n"); > > + return -EINVAL; > > + } > > + > > + vasid = uattr.vas_id; > > + > > + memset(&txattr, 0, sizeof(struct vas_tx_win_attr)); > > You could define txattr with `struct vas_tx_win_attr txattr = {};` and > avoid the explicit memset. > > > + vas_init_tx_win_attr(&txattr, VAS_COP_TYPE_GZIP); > > + > > + txattr.lpid = mfspr(SPRN_LPID); > > + txattr.pidr = mfspr(SPRN_PID); > > + txattr.user_win = true; > > + txattr.rsvd_txbuf_count = false; > > + txattr.pswid = false; > > + /* > > + * txattr.wcreds_max is set to VAS_WCREDS_DEFAULT (1024) in > > + * vas-window.c, but can be changed specific to GZIP depends > > + * on user space need. > > + * If needed to set txattr.wcreds_max here. > > + */ > > Who could set this? You mention userspace need but it looks like the > user cannot set this. Is this a message to future kernel developers? set the default value in vax_tx_win_open() (vas_window.c) if it is not set here. credits limit can set here if we decide to use non-default value for user space windows. Not allowing user space to set this value. Yes, this comment is for kernel developers. I can remove this comment to remove the confusion. > > > + > > + pr_devel("Pid %d: Opening txwin, PIDR %ld\n", txattr.pidr, > > + mfspr(SPRN_PID)); > > + > > + txwin = vas_tx_win_open(vasid, VAS_COP_TYPE_GZIP, &txattr); > > + if (IS_ERR(txwin)) { > > + pr_err("%s() vas_tx_win_open() failed, %ld\n", __func__, > > + PTR_ERR(txwin)); > > + return PTR_ERR(txwin); > > + } > > + > > + nxti->txwin = txwin; > > + > > + return 0; > > +} > > + > > +static int coproc_release(struct inode *inode, struct file *fp) > > +{ > > + struct coproc_instance *instance; > > + > > + instance = fp->private_data; > > + > > + if (instance && instance->txwin) { > > + vas_win_close(instance->txwin); > > + instance->txwin = NULL; > > + } > > + > > + /* > > + * We don't know here if user has other receive windows > > + * open, so we can't really call clear_thread_tidr(). > > + * So, once the process calls set_thread_tidr(), the > > + * TIDR value sticks around until process exits, resulting > > + * in an extra copy in restore_sprs(). > > + */ > > + > > + kfree(instance); > > + fp->private_data = NULL; > > + atomic_dec(&coproc_instid); > > + > > + return 0; > > +} > > + > > +static int coproc_mmap(struct file *fp, struct vm_area_struct *vma) > > +{ > > + int rc; > > + pgprot_t prot; > > + u64 paste_addr; > > + unsigned long pfn; > > + struct coproc_instance *instance = fp->private_data; > > + > > + if ((vma->vm_end - vma->vm_start) > PAGE_SIZE) { > > + pr_debug("%s(): size 0x%zx, PAGE_SIZE 0x%zx\n", __func__, > > + (vma->vm_end - vma->vm_start), PAGE_SIZE); > > + return -EINVAL; > > + } > > + > > + /* Ensure instance has an open send window */ > > + if (!instance->txwin) { > > + pr_err("%s(): No send window open?\n", __func__); > > + return -EINVAL; > > + } > > + > > + vas_win_paste_addr(instance->txwin, &paste_addr, NULL); > > + pfn = paste_addr >> PAGE_SHIFT; > > + > > + /* flags, page_prot from cxl_mmap(), except we want cachable */ > > + vma->vm_flags |= VM_IO | VM_PFNMAP; > > + vma->vm_page_prot = pgprot_cached(vma->vm_page_prot); > > + > > + prot = __pgprot(pgprot_val(vma->vm_page_prot) | _PAGE_DIRTY); > > + > > + rc = remap_pfn_range(vma, vma->vm_start, pfn + vma->vm_pgoff, > > + vma->vm_end - vma->vm_start, prot); > > + > > + pr_devel("%s(): paste addr %llx at %lx, rc %d\n", __func__, > > + paste_addr, vma->vm_start, rc); > > + > > + return rc; > > +} > > + > > +static long coproc_ioctl(struct file *fp, unsigned int cmd, unsigned long > > arg) > > +{ > > + switch (cmd) { > > + case VAS_TX_WIN_OPEN: > > + return coproc_ioc_tx_win_open(fp, arg); > > + default: > > + return -EINVAL; > > + } > > +} > > + > > +static struct file_operations coproc_fops = { > > + .open = coproc_open, > > + .release = coproc_release, > > + .mmap = coproc_mmap, > > + .unlocked_ioctl = coproc_ioctl, > > +}; > > + > > +/* > > + * Supporting only nx-gzip coprocessor type now, but this API code > > + * extended to other coprocessor types later. > > + */ > > +int vas_register_coproc_api(struct module *mod) > > +{ > > + int rc = -EINVAL; > > + dev_t devno; > > + > > + rc = alloc_chrdev_region(&coproc_device.devt, 1, 1, "nx-gzip"); > > + if (rc) { > > + pr_err("Unable to allocate coproc major number: %i\n", rc); > > + return rc; > > + } > > + > > + pr_devel("NX-GZIP device allocated, dev [%i,%i]\n", > > + MAJOR(coproc_device.devt), MINOR(coproc_device.devt)); > > + > > + coproc_device.class = class_create(mod, "nx-gzip"); > > + if (IS_ERR(coproc_device.class)) { > > + rc = PTR_ERR(coproc_device.class); > > + pr_err("Unable to create NX-GZIP class %d\n", rc); > > + goto err_class; > > + } > > + coproc_device.class->devnode = coproc_devnode; > > + > > + coproc_fops.owner = mod; > > + cdev_init(&coproc_device.cdev, &coproc_fops); > > Looking into this coproc_fops thing more: > > I find this API very confusing. The comment at the top of the function > says it will be extended, but there's only one coproc_fops, so currently > it can only be instantiated once and owned by one module. Much of the > rest of that function is also very much based around the nx-gzip > coprocessor. > > I'm not fully certain about how this should work, but I think probably > it either needs to be fully generic or fully nx-gzip only for now. I > would make it fully nx-gzip only and extend it later, but I'm not fussy. We are adding only for NX-GZIP right now and mentioned nx-gzip. Most of interfaces in coproc_fops such as open/mmap/close should be common for any coprocs except ioctl or new ioctl cmd. register_coproc_api creates device node and register fs API specific to coprocessor. user space use fs API to establish communication channel (using open, ioctl, mmap) to NX. How about defining coproc_nxgzip_fs to remove this confusion. > > > + > > + devno = MKDEV(MAJOR(coproc_device.devt), 0); > > + rc = cdev_add(&coproc_device.cdev, devno, 1); > > + if (rc) { > > + pr_err("cdev_add() failed %d\n", rc); > > + goto err_cdev; > > + } > > + > > + coproc_device.device = device_create(coproc_device.class, NULL, > > + devno, NULL, coproc_dev_name, MINOR(devno)); > > + if (IS_ERR(coproc_device.device)) { > > + rc = PTR_ERR(coproc_device.device); > > + pr_err("Unable to create coproc-%d %d\n", MINOR(devno), rc); > > + goto err; > > + } > > + > > + pr_devel("%s: Added dev [%d,%d]\n", __func__, MAJOR(devno), > > + MINOR(devno)); > > + > > + return 0; > > + > > +err: > > + cdev_del(&coproc_device.cdev); > > +err_cdev: > > + class_destroy(coproc_device.class); > > +err_class: > > + unregister_chrdev_region(coproc_device.devt, 1); > > + return rc; > > +} > > +EXPORT_SYMBOL_GPL(vas_register_coproc_api); > > + > > +void vas_unregister_coproc_api(void) > > +{ > > + dev_t devno; > > + > > + cdev_del(&coproc_device.cdev); > > + devno = MKDEV(MAJOR(coproc_device.devt), 0); > > + device_destroy(coproc_device.class, devno); > > + > > + class_destroy(coproc_device.class); > > + unregister_chrdev_region(coproc_device.devt, 1); > > +} > > +EXPORT_SYMBOL_GPL(vas_unregister_coproc_api); > > diff --git a/arch/powerpc/platforms/powernv/vas-window.c > > b/arch/powerpc/platforms/powernv/vas-window.c > > index e9ab851..7484296 100644 > > --- a/arch/powerpc/platforms/powernv/vas-window.c > > +++ b/arch/powerpc/platforms/powernv/vas-window.c > > @@ -26,7 +26,7 @@ > > * Compute the paste address region for the window @window using the > > * ->paste_base_addr and ->paste_win_id_shift we got from device tree. > > */ > > -static void compute_paste_address(struct vas_window *window, u64 *addr, > > int *len) > > +void vas_win_paste_addr(struct vas_window *window, u64 *addr, int *len) > > { > > int winid; > > u64 base, shift; > > @@ -80,7 +80,7 @@ static void *map_paste_region(struct vas_window *txwin) > > goto free_name; > > > > txwin->paste_addr_name = name; > > - compute_paste_address(txwin, &start, &len); > > + vas_win_paste_addr(txwin, &start, &len); > > > > if (!request_mem_region(start, len, name)) { > > pr_devel("%s(): request_mem_region(0x%llx, %d) failed\n", > > @@ -138,7 +138,7 @@ static void unmap_paste_region(struct vas_window > > *window) > > u64 busaddr_start; > > > > if (window->paste_kaddr) { > > - compute_paste_address(window, &busaddr_start, &len); > > + vas_win_paste_addr(window, &busaddr_start, &len); > > unmap_region(window->paste_kaddr, busaddr_start, len); > > window->paste_kaddr = NULL; > > kfree(window->paste_addr_name); > > diff --git a/arch/powerpc/platforms/powernv/vas.h > > b/arch/powerpc/platforms/powernv/vas.h > > index 8c39a7d..a10abed 100644 > > --- a/arch/powerpc/platforms/powernv/vas.h > > +++ b/arch/powerpc/platforms/powernv/vas.h > > @@ -431,6 +431,8 @@ struct vas_winctx { > > extern void vas_return_credit(struct vas_window *window, bool tx); > > extern struct vas_window *vas_pswid_to_window(struct vas_instance *vinst, > > uint32_t pswid); > > +extern void vas_win_paste_addr(struct vas_window *window, u64 *addr, > > + int *len); > > > > static inline int vas_window_pid(struct vas_window *window) > > { > > -- > > 1.8.3.1