Hi Jacob,

I love your patch! Yet something to improve:

[auto build test ERROR on iommu/next]
[also build test ERROR on linux/master linus/master v5.12-rc1 next-20210303]
[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/Jacob-Pan/Misc-vSVA-fixes-for-VT-d/20210219-141141
base:   https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git next
config: ia64-randconfig-r023-20210304 (attached as .config)
compiler: ia64-linux-gcc (GCC) 9.3.0
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/0day-ci/linux/commit/4c1de3403ecb6f91cc1bdc5e3ca81f16a2ffc0b5
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Jacob-Pan/Misc-vSVA-fixes-for-VT-d/20210219-141141
        git checkout 4c1de3403ecb6f91cc1bdc5e3ca81f16a2ffc0b5
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=ia64 

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

All errors (new ones prefixed by >>):

   In file included from arch/ia64/include/asm/pgtable.h:154,
                    from include/linux/pgtable.h:6,
                    from include/linux/mm.h:33,
                    from include/linux/scatterlist.h:8,
                    from include/linux/dma-mapping.h:10,
                    from include/linux/iova.h:16,
                    from include/linux/intel-iommu.h:14,
                    from drivers/iommu/intel/pasid.c:15:
   arch/ia64/include/asm/mmu_context.h: In function 'reload_context':
   arch/ia64/include/asm/mmu_context.h:127:41: warning: variable 'old_rr4' set but not used [-Wunused-but-set-variable]
     127 |  unsigned long rr0, rr1, rr2, rr3, rr4, old_rr4;
         |                                         ^~~~~~~
   drivers/iommu/intel/pasid.c: In function 'pasid_enable_wpe':
>> drivers/iommu/intel/pasid.c:536:22: error: implicit declaration of function 'read_cr0' [-Werror=implicit-function-declaration]
     536 |  unsigned long cr0 = read_cr0();
         |                      ^~~~~~~~
   In file included from include/linux/build_bug.h:5,
                    from include/linux/bits.h:22,
                    from include/linux/bitops.h:6,
                    from drivers/iommu/intel/pasid.c:12:
>> drivers/iommu/intel/pasid.c:539:23: error: 'X86_CR0_WP' undeclared (first use in this function)
     539 |  if (unlikely(!(cr0 & X86_CR0_WP))) {
         |                       ^~~~~~~~~~
   include/linux/compiler.h:78:42: note: in definition of macro 'unlikely'
      78 | # define unlikely(x) __builtin_expect(!!(x), 0)
         |                                          ^
   drivers/iommu/intel/pasid.c:539:23: note: each undeclared identifier is reported only once for each function it appears in
     539 |  if (unlikely(!(cr0 & X86_CR0_WP))) {
         |                       ^~~~~~~~~~
   include/linux/compiler.h:78:42: note: in definition of macro 'unlikely'
      78 | # define unlikely(x) __builtin_expect(!!(x), 0)
         |                                          ^
   cc1: some warnings being treated as errors


vim +/read_cr0 +536 drivers/iommu/intel/pasid.c

   533	
   534	static inline int pasid_enable_wpe(struct pasid_entry *pte)
   535	{
 > 536		unsigned long cr0 = read_cr0();
   537	
   538		/* CR0.WP is normally set but just to be sure */
 > 539		if (unlikely(!(cr0 & X86_CR0_WP))) {
   540			pr_err_ratelimited("No CPU write protect!\n");
   541			return -EINVAL;
   542		}
   543		pasid_set_wpe(pte);
   544	
   545		return 0;
   546	};
   547	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org