tree: https://github.com/intel/tdx.git guest head: 422a2465ebe67c0db36e855df7f9d7018f878c28 commit: 0cb8b5708223bba7e3ccd67754376d91305a1085 [40/44] x86/tdx: Make VirtIO use DMA API in TDX guest config: s390-randconfig-r032-20201012 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project a324d8f964bf421fa7d8b882b0f64ead28c4149c) 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 # install s390 cross compiling tool for clang build # apt-get install binutils-s390x-linux-gnu # https://github.com/intel/tdx/commit/0cb8b5708223bba7e3ccd67754376d91305a1085 git remote add intel-tdx https://github.com/intel/tdx.git git fetch --no-tags intel-tdx guest git checkout 0cb8b5708223bba7e3ccd67754376d91305a1085 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=s390 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x)) ^ include/uapi/linux/swab.h:119:21: note: expanded from macro '__swab32' ___constant_swab32(x) : \ ^ include/uapi/linux/swab.h:19:12: note: expanded from macro '___constant_swab32' (((__u32)(x) & (__u32)0x000000ffUL) << 24) | \ ^ In file included from drivers/virtio/virtio_ring.c:6: In file included from include/linux/virtio.h:7: In file included from include/linux/scatterlist.h:9: In file included from arch/s390/include/asm/io.h:72: include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x)) ^ include/uapi/linux/swab.h:119:21: note: expanded from macro '__swab32' ___constant_swab32(x) : \ ^ include/uapi/linux/swab.h:20:12: note: expanded from macro '___constant_swab32' (((__u32)(x) & (__u32)0x0000ff00UL) << 8) | \ ^ In file included from drivers/virtio/virtio_ring.c:6: In file included from include/linux/virtio.h:7: In file included from include/linux/scatterlist.h:9: In file included from arch/s390/include/asm/io.h:72: include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x)) ^ include/uapi/linux/swab.h:119:21: note: expanded from macro '__swab32' ___constant_swab32(x) : \ ^ include/uapi/linux/swab.h:21:12: note: expanded from macro '___constant_swab32' (((__u32)(x) & (__u32)0x00ff0000UL) >> 8) | \ ^ In file included from drivers/virtio/virtio_ring.c:6: In file included from include/linux/virtio.h:7: In file included from include/linux/scatterlist.h:9: In file included from arch/s390/include/asm/io.h:72: include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x)) ^ include/uapi/linux/swab.h:119:21: note: expanded from macro '__swab32' ___constant_swab32(x) : \ ^ include/uapi/linux/swab.h:22:12: note: expanded from macro '___constant_swab32' (((__u32)(x) & (__u32)0xff000000UL) >> 24))) ^ In file included from drivers/virtio/virtio_ring.c:6: In file included from include/linux/virtio.h:7: In file included from include/linux/scatterlist.h:9: In file included from arch/s390/include/asm/io.h:72: include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x)) ^ include/uapi/linux/swab.h:120:12: note: expanded from macro '__swab32' __fswab32(x)) ^ In file included from drivers/virtio/virtio_ring.c:6: In file included from include/linux/virtio.h:7: In file included from include/linux/scatterlist.h:9: In file included from arch/s390/include/asm/io.h:72: include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writeb(value, PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:511:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:521:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:609:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:617:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:625:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:634:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:643:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:652:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ if (is_tdx_guest()) ^ 20 warnings and 1 error generated. vim +/is_tdx_guest +258 drivers/virtio/virtio_ring.c 214 215 /* 216 * Modern virtio devices have feature bits to specify whether they need a 217 * quirk and bypass the IOMMU. If not there, just use the DMA API. 218 * 219 * If there, the interaction between virtio and DMA API is messy. 220 * 221 * On most systems with virtio, physical addresses match bus addresses, 222 * and it doesn't particularly matter whether we use the DMA API. 223 * 224 * On some systems, including Xen and any system with a physical device 225 * that speaks virtio behind a physical IOMMU, we must use the DMA API 226 * for virtio DMA to work at all. 227 * 228 * On other systems, including SPARC and PPC64, virtio-pci devices are 229 * enumerated as though they are behind an IOMMU, but the virtio host 230 * ignores the IOMMU, so we must either pretend that the IOMMU isn't 231 * there or somehow map everything as the identity. 232 * 233 * For the time being, we preserve historic behavior and bypass the DMA 234 * API. 235 * 236 * TODO: install a per-device DMA ops structure that does the right thing 237 * taking into account all the above quirks, and use the DMA API 238 * unconditionally on data path. 239 */ 240 241 static bool vring_use_dma_api(struct virtio_device *vdev) 242 { 243 if (!virtio_has_dma_quirk(vdev)) 244 return true; 245 246 /* Otherwise, we are left to guess. */ 247 /* 248 * In theory, it's possible to have a buggy QEMU-supposed 249 * emulated Q35 IOMMU and Xen enabled at the same time. On 250 * such a configuration, virtio has never worked and will 251 * not work without an even larger kludge. Instead, enable 252 * the DMA API if we're a Xen guest, which at least allows 253 * all of the sensible Xen configurations to work correctly. 254 */ 255 if (xen_domain()) 256 return true; 257 259 return true; 260 261 return false; 262 } 263 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org