Re: [PATCH v12 1/1] vfio/nvgpu: Add vfio pci variant module for grace hopper

From: kernel test robot
Date: Sat Nov 04 2023 - 05:36:11 EST

Hi,

kernel test robot noticed the following build warnings:

[auto build test WARNING on awilliam-vfio/for-linus]
[also build test WARNING on linus/master v6.6 next-20231103]
[cannot apply to awilliam-vfio/next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url: https://github.com/intel-lab-lkp/linux/commits/ankita-nvidia-com/vfio-nvgpu-Add-vfio-pci-variant-module-for-grace-hopper/20231017-131546
base: https://github.com/awilliam/linux-vfio.git for-linus
patch link: https://lore.kernel.org/r/20231015163047.20391-1-ankita%40nvidia.com
patch subject: [PATCH v12 1/1] vfio/nvgpu: Add vfio pci variant module for grace hopper
config: powerpc-allmodconfig (https://download.01.org/0day-ci/archive/20231104/202311041743.tL7StQAH-lkp@xxxxxxxxx/config)
compiler: powerpc64-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231104/202311041743.tL7StQAH-lkp@xxxxxxxxx/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202311041743.tL7StQAH-lkp@xxxxxxxxx/

All warnings (new ones prefixed by >>):

>> drivers/vfio/pci/nvgrace-gpu/main.c:226:9: warning: no previous prototype for 'nvgrace_gpu_read_mem' [-Wmissing-prototypes]
226 | ssize_t nvgrace_gpu_read_mem(void __user *buf, size_t count, loff_t *ppos,
| ^~~~~~~~~~~~~~~~~~~~
>> drivers/vfio/pci/nvgrace-gpu/main.c:298:9: warning: no previous prototype for 'nvgrace_gpu_write_mem' [-Wmissing-prototypes]
298 | ssize_t nvgrace_gpu_write_mem(size_t count, loff_t *ppos, const void __user *buf,
| ^~~~~~~~~~~~~~~~~~~~~


vim +/nvgrace_gpu_read_mem +226 drivers/vfio/pci/nvgrace-gpu/main.c

214
215 /*
216 * Read count bytes from the device memory at an offset. The actual device
217 * memory size (available) may not be a power-of-2. So the driver fakes
218 * the size to a power-of-2 (reported) when exposing to a user space driver.
219 *
220 * Read request beyond the actual device size is filled with ~0, while
221 * those beyond the actual reported size is skipped.
222 *
223 * A read from a negative or an offset greater than reported size, a negative
224 * count are considered error conditions and returned with an -EINVAL.
225 */
> 226 ssize_t nvgrace_gpu_read_mem(void __user *buf, size_t count, loff_t *ppos,
227 struct nvgrace_gpu_vfio_pci_core_device *nvdev)
228 {
229 u64 offset = *ppos & VFIO_PCI_OFFSET_MASK;
230 size_t mem_count, i, bar_size = roundup_pow_of_two(nvdev->memlength);
231 u8 val = 0xFF;
232
233 if (offset >= bar_size)
234 return -EINVAL;
235
236 /* Clip short the read request beyond reported BAR size */
237 count = min(count, bar_size - (size_t)offset);
238
239 /*
240 * Determine how many bytes to be actually read from the device memory.
241 * Read request beyond the actual device memory size is filled with ~0,
242 * while those beyond the actual reported size is skipped.
243 */
244 if (offset >= nvdev->memlength)
245 mem_count = 0;
246 else
247 mem_count = min(count, nvdev->memlength - (size_t)offset);
248
249 /*
250 * Handle read on the BAR2 region. Map to the target device memory
251 * physical address and copy to the request read buffer.
252 */
253 if (copy_to_user(buf, (u8 *)nvdev->memmap + offset, mem_count))
254 return -EFAULT;
255
256 /*
257 * Only the device memory present on the hardware is mapped, which may
258 * not be power-of-2 aligned. A read to an offset beyond the device memory
259 * size is filled with ~0.
260 */
261 for (i = mem_count; i < count; i++)
262 put_user(val, (unsigned char __user *)(buf + i));
263
264 *ppos += count;
265 return count;
266 }
267
268 static ssize_t nvgrace_gpu_vfio_pci_read(struct vfio_device *core_vdev,
269 char __user *buf, size_t count, loff_t *ppos)
270 {
271 unsigned int index = VFIO_PCI_OFFSET_TO_INDEX(*ppos);
272 struct nvgrace_gpu_vfio_pci_core_device *nvdev = container_of(
273 core_vdev, struct nvgrace_gpu_vfio_pci_core_device, core_device.vdev);
274 int ret;
275
276 if (index == VFIO_PCI_BAR2_REGION_INDEX) {
277 ret = nvgrace_gpu_memmap(nvdev);
278 if (ret)
279 return ret;
280
281 return nvgrace_gpu_read_mem(buf, count, ppos, nvdev);
282 }
283
284 return vfio_pci_core_read(core_vdev, buf, count, ppos);
285 }
286
287 /*
288 * Write count bytes to the device memory at a given offset. The actual device
289 * memory size (available) may not be a power-of-2. So the driver fakes the
290 * size to a power-of-2 (reported) when exposing to a user space driver.
291 *
292 * Write request beyond the actual device size are dropped, while those
293 * beyond the actual reported size are skipped entirely.
294 *
295 * A write to a negative or an offset greater than the reported size, a
296 * negative count are considered error conditions and returned with an -EINVAL.
297 */
> 298 ssize_t nvgrace_gpu_write_mem(size_t count, loff_t *ppos, const void __user *buf,
299 struct nvgrace_gpu_vfio_pci_core_device *nvdev)
300 {
301 u64 offset = *ppos & VFIO_PCI_OFFSET_MASK;
302 size_t mem_count, bar_size = roundup_pow_of_two(nvdev->memlength);
303
304 if (offset >= bar_size)
305 return -EINVAL;
306
307 /* Clip short the write request beyond reported BAR size */
308 count = min(count, bar_size - (size_t)offset);
309
310 /*
311 * Determine how many bytes to be actually written to the device memory.
312 * Do not write to the offset beyond available size.
313 */
314 if (offset >= nvdev->memlength)
315 goto exitfn;
316
317 mem_count = min(count, nvdev->memlength - (size_t)offset);
318
319 /*
320 * Only the device memory present on the hardware is mapped, which may
321 * not be power-of-2 aligned. A write to the BAR2 region implies an
322 * access outside the available device memory on the hardware. Drop
323 * those write requests.
324 */
325 if (copy_from_user((u8 *)nvdev->memmap + offset, buf, mem_count))
326 return -EFAULT;
327
328 exitfn:
329 *ppos += count;
330 return count;
331 }
332

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki