On Mon, Nov 30, 2020 at 6:28 AM Daniel Vetter <daniel@xxxxxxxx> wrote: > > So I guess kvm platforms that don't set KVM_ARCH_WANT_MMU_NOTIFIER exist, > and at least on powerpc they're consistent with KVM_CAP_SYNC_MMU > signalling that the guest pagetables stays in sync automatically with any > updates. So for that case I guess we could use unsafe_follow_pfn. > > But on s390 this seems different: No mmu notifier, but KVM_CAP_SYNC_MMU is > set. So I guess there's some hardware magic on s390 that I don't know > about. + Vasily + Heiko +s390 > > Not sure what to do with this now here ... > -Daniel > > > On Sat, Nov 28, 2020 at 03:10:40AM +0800, kernel test robot wrote: > > Hi Daniel, > > > > I love your patch! Yet something to improve: > > > > [auto build test ERROR on linuxtv-media/master] > > [also build test ERROR on char-misc/char-misc-testing v5.10-rc5] > > [cannot apply to hnaz-linux-mm/master next-20201127] > > [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] > > > > url: https://github.com/0day-ci/linux/commits/Daniel-Vetter/follow_pfn-and-other-iomap-races/20201128-004421 > > base: git://linuxtv.org/media_tree.git master > > config: s390-randconfig-r032-20201127 (attached as .config) > > compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project f095ac11a9550530a4a54298debb8b04b36422be) > > 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/0day-ci/linux/commit/d76a3489433ce67d45da86aa12953385427f0ac9 > > git remote add linux-review https://github.com/0day-ci/linux > > git fetch --no-tags linux-review Daniel-Vetter/follow_pfn-and-other-iomap-races/20201128-004421 > > git checkout d76a3489433ce67d45da86aa12953385427f0ac9 > > # 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@xxxxxxxxx> > > > > All errors (new ones prefixed by >>): > > > > In file included from arch/s390/include/asm/kvm_para.h:25: > > In file included from arch/s390/include/asm/diag.h:12: > > In file included from include/linux/if_ether.h:19: > > In file included from include/linux/skbuff.h:31: > > In file included from include/linux/dma-mapping.h:10: > > In file included from include/linux/scatterlist.h:9: > > In file included from arch/s390/include/asm/io.h:80: > > 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 arch/s390/kvm/../../../virt/kvm/kvm_main.c:18: > > In file included from include/linux/kvm_host.h:32: > > In file included from include/linux/kvm_para.h:5: > > In file included from include/uapi/linux/kvm_para.h:36: > > In file included from arch/s390/include/asm/kvm_para.h:25: > > In file included from arch/s390/include/asm/diag.h:12: > > In file included from include/linux/if_ether.h:19: > > In file included from include/linux/skbuff.h:31: > > In file included from include/linux/dma-mapping.h:10: > > In file included from include/linux/scatterlist.h:9: > > In file included from arch/s390/include/asm/io.h:80: > > 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 arch/s390/kvm/../../../virt/kvm/kvm_main.c:18: > > In file included from include/linux/kvm_host.h:32: > > In file included from include/linux/kvm_para.h:5: > > In file included from include/uapi/linux/kvm_para.h:36: > > In file included from arch/s390/include/asm/kvm_para.h:25: > > In file included from arch/s390/include/asm/diag.h:12: > > In file included from include/linux/if_ether.h:19: > > In file included from include/linux/skbuff.h:31: > > In file included from include/linux/dma-mapping.h:10: > > In file included from include/linux/scatterlist.h:9: > > In file included from arch/s390/include/asm/io.h:80: > > 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 arch/s390/kvm/../../../virt/kvm/kvm_main.c:18: > > In file included from include/linux/kvm_host.h:32: > > In file included from include/linux/kvm_para.h:5: > > In file included from include/uapi/linux/kvm_para.h:36: > > In file included from arch/s390/include/asm/kvm_para.h:25: > > In file included from arch/s390/include/asm/diag.h:12: > > In file included from include/linux/if_ether.h:19: > > In file included from include/linux/skbuff.h:31: > > In file included from include/linux/dma-mapping.h:10: > > In file included from include/linux/scatterlist.h:9: > > In file included from arch/s390/include/asm/io.h:80: > > 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); > > ~~~~~~~~~~ ^ > > >> arch/s390/kvm/../../../virt/kvm/kvm_main.c:1894:40: error: no member named 'mmu_notifier' in 'struct kvm' > > r = follow_pfn(vma, addr, &pfn, &kvm->mmu_notifier); > > ~~~ ^ > > arch/s390/kvm/../../../virt/kvm/kvm_main.c:1909:41: error: no member named 'mmu_notifier' in 'struct kvm' > > r = follow_pfn(vma, addr, &pfn, &kvm->mmu_notifier); > > ~~~ ^ > > 20 warnings and 2 errors generated. > > > > vim +1894 arch/s390/kvm/../../../virt/kvm/kvm_main.c > > > > 1885 > > 1886 static int hva_to_pfn_remapped(struct kvm *kvm, struct vm_area_struct *vma, > > 1887 unsigned long addr, bool *async, > > 1888 bool write_fault, bool *writable, > > 1889 kvm_pfn_t *p_pfn) > > 1890 { > > 1891 unsigned long pfn; > > 1892 int r; > > 1893 > > > 1894 r = follow_pfn(vma, addr, &pfn, &kvm->mmu_notifier); > > 1895 if (r) { > > 1896 /* > > 1897 * get_user_pages fails for VM_IO and VM_PFNMAP vmas and does > > 1898 * not call the fault handler, so do it here. > > 1899 */ > > 1900 bool unlocked = false; > > 1901 r = fixup_user_fault(current->mm, addr, > > 1902 (write_fault ? FAULT_FLAG_WRITE : 0), > > 1903 &unlocked); > > 1904 if (unlocked) > > 1905 return -EAGAIN; > > 1906 if (r) > > 1907 return r; > > 1908 > > 1909 r = follow_pfn(vma, addr, &pfn, &kvm->mmu_notifier); > > 1910 if (r) > > 1911 return r; > > 1912 > > 1913 } > > 1914 > > 1915 if (writable) > > 1916 *writable = true; > > 1917 > > 1918 /* > > 1919 * Get a reference here because callers of *hva_to_pfn* and > > 1920 * *gfn_to_pfn* ultimately call kvm_release_pfn_clean on the > > 1921 * returned pfn. This is only needed if the VMA has VM_MIXEDMAP > > 1922 * set, but the kvm_get_pfn/kvm_release_pfn_clean pair will > > 1923 * simply do nothing for reserved pfns. > > 1924 * > > 1925 * Whoever called remap_pfn_range is also going to call e.g. > > 1926 * unmap_mapping_range before the underlying pages are freed, > > 1927 * causing a call to our MMU notifier. > > 1928 */ > > 1929 kvm_get_pfn(pfn); > > 1930 > > 1931 *p_pfn = pfn; > > 1932 return 0; > > 1933 } > > 1934 > > > > --- > > 0-DAY CI Kernel Test Service, Intel Corporation > > https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx > > > > -- > Daniel Vetter > Software Engineer, Intel Corporation > http://blog.ffwll.ch > > -- > You received this message because you are subscribed to the Google Groups "Clang Built Linux" group. > To unsubscribe from this group and stop receiving emails from it, send an email to clang-built-linux+unsubscribe@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/20201130142820.GN401619%40phenom.ffwll.local. -- Thanks, ~Nick Desaulniers
