Re: [PATCH 2/4] swiotlb: Add a new cc-swiotlb implementation for Confidential VMs

kernel test robot
2023-01-28T12:03:38Z

Hi GuoRui.Yu",

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on tip/x86/core]
[also build test WARNING on joro-iommu/next driver-core/driver-core-testing driver-core/driver-core-next driver-core/driver-core-linus linus/master v6.2-rc5 next-20230127]
[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/GuoRui-Yu/swiotlb-Add-a-new-cc-swiotlb-implementation-for-Confidential-VMs/20230128-181154
patch link: https://lore.kernel.org/r/20230128083254.86012-3-GuoRui.Yu%40linux.alibaba.com
patch subject: [PATCH 2/4] swiotlb: Add a new cc-swiotlb implementation for Confidential VMs
config: alpha-allyesconfig (https://download.01.org/0day-ci/archive/20230128/202301281925.XYfOkJnF-lkp@intel.com/config)
compiler: alpha-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/9345d2c75b5994cec46ad0abf12f01ed91742e81
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review GuoRui-Yu/swiotlb-Add-a-new-cc-swiotlb-implementation-for-Confidential-VMs/20230128-181154
git checkout 9345d2c75b5994cec46ad0abf12f01ed91742e81
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=alpha olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=alpha SHELL=/bin/bash kernel/dma/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

kernel/dma/cc-swiotlb.c: In function 'swiotlb_bounce':
>> kernel/dma/cc-swiotlb.c:174:32: warning: variable 'tlb_end' set but not used [-Wunused-but-set-variable]
174 | phys_addr_t orig_addr, tlb_end, slot_start, slot_end = tlb_addr ;
| ^~~~~~~
kernel/dma/cc-swiotlb.c: At top level:
>> kernel/dma/cc-swiotlb.c:492:13: warning: no previous prototype for 'swiotlb_hint_cpus' [-Wmissing-prototypes]
492 | void __init swiotlb_hint_cpus(int cpus) {}
| ^~~~~~~~~~~~~~~~~

vim +/tlb_end +174 kernel/dma/cc-swiotlb.c

167
168 /*
169 * Bounce: copy the swiotlb buffer from or back to the original dma location
170 */
171 void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size,
172 enum dma_data_direction dir)
173 {
> 174 phys_addr_t orig_addr, tlb_end, slot_start, slot_end = tlb_addr ;
175 struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
176 struct io_tlb_slot *slot;
177 unsigned long pfn;
178 void *backing_addr;
179 size_t alloc_size;
180
181 slot = xa_find_after(mem->mapping, (unsigned long*)&slot_end, ULONG_MAX, XA_PRESENT);
182 if (!slot) {
183 dev_WARN_ONCE(dev, 1, "TLB buffer not found.\n");
184 return;
185 }
186
187 orig_addr = slot->orig_addr;
188 alloc_size = slot->alloc_size;
189 slot_start = slot_end - slot->orig_size;
190 tlb_end = tlb_addr + size;
191
192 pfn = PFN_DOWN(orig_addr);
193 if (PageHighMem(pfn_to_page(pfn))) {
194 dev_WARN_ONCE(dev, 1, "Unexpected high memory.\n");
195 return;
196 }
197
198 if (size > alloc_size) {
199 dev_WARN_ONCE(dev, 1,
200 "Buffer overflow detected. Allocation size: %zu. Mapping size: %zu.\n",
201 alloc_size, size);
202 size = alloc_size;
203 }
204
205 backing_addr = slot->va + (tlb_addr - slot_start);
206
207 if (dir == DMA_TO_DEVICE) {
208 memcpy(backing_addr, phys_to_virt(orig_addr), size);
209 } else {
210 memcpy(phys_to_virt(orig_addr), backing_addr, size);
211 }
212 }
213

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