Re: [PATCH v5 10/14] mm: x86: Invoke hypercall when page encryption status is changed

[kbuild test robot]

Hi Ashish,

I love your patch! Yet something to improve:

[auto build test ERROR on tip/x86/mm]
[also build test ERROR on v5.6]
[cannot apply to kvm/linux-next tip/x86/core next-20200327]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Ashish-Kalra/Add-AMD-SEV-guest-live-migration-support/20200330-094122
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git aa61ee7b9ee3cb84c0d3a842b0d17937bf024c46
config: i386-tinyconfig (attached as .config)
compiler: gcc-7 (Debian 7.5.0-5) 7.5.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@xxxxxxxxx>

All errors (new ones prefixed by >>):

   arch/x86/mm/pat/set_memory.c: In function '__set_memory_enc_dec':
>> arch/x86/mm/pat/set_memory.c:1995:2: error: implicit declaration of function 'page_encryption_changed'; did you mean 'sme_encrypt_kernel'? [-Werror=implicit-function-declaration]
     page_encryption_changed(addr, numpages, enc);
     ^~~~~~~~~~~~~~~~~~~~~~~
     sme_encrypt_kernel
   cc1: some warnings being treated as errors

vim +1995 arch/x86/mm/pat/set_memory.c

  1950	
  1951	static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
  1952	{
  1953		struct cpa_data cpa;
  1954		int ret;
  1955	
  1956		/* Nothing to do if memory encryption is not active */
  1957		if (!mem_encrypt_active())
  1958			return 0;
  1959	
  1960		/* Should not be working on unaligned addresses */
  1961		if (WARN_ONCE(addr & ~PAGE_MASK, "misaligned address: %#lx\n", addr))
  1962			addr &= PAGE_MASK;
  1963	
  1964		memset(&cpa, 0, sizeof(cpa));
  1965		cpa.vaddr = &addr;
  1966		cpa.numpages = numpages;
  1967		cpa.mask_set = enc ? __pgprot(_PAGE_ENC) : __pgprot(0);
  1968		cpa.mask_clr = enc ? __pgprot(0) : __pgprot(_PAGE_ENC);
  1969		cpa.pgd = init_mm.pgd;
  1970	
  1971		/* Must avoid aliasing mappings in the highmem code */
  1972		kmap_flush_unused();
  1973		vm_unmap_aliases();
  1974	
  1975		/*
  1976		 * Before changing the encryption attribute, we need to flush caches.
  1977		 */
  1978		cpa_flush(&cpa, 1);
  1979	
  1980		ret = __change_page_attr_set_clr(&cpa, 1);
  1981	
  1982		/*
  1983		 * After changing the encryption attribute, we need to flush TLBs again
  1984		 * in case any speculative TLB caching occurred (but no need to flush
  1985		 * caches again).  We could just use cpa_flush_all(), but in case TLB
  1986		 * flushing gets optimized in the cpa_flush() path use the same logic
  1987		 * as above.
  1988		 */
  1989		cpa_flush(&cpa, 0);
  1990	
  1991		/* Notify hypervisor that a given memory range is mapped encrypted
  1992		 * or decrypted. The hypervisor will use this information during the
  1993		 * VM migration.
  1994		 */
> 1995		page_encryption_changed(addr, numpages, enc);
  1996	
  1997		return ret;
  1998	}
  1999	

---
0-DAY CI Kernel Test Service, Intel Corporation
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