Re: [PATCH 15/22] kvm: mmu: Support changed pte notifier in tdp MMU

[kernel test robot <lkp@intel.com>]

[-- Attachment #1: Type: text/plain, Size: 5071 bytes --]

CC: kbuild-all(a)lists.01.org
In-Reply-To: <20200925212302.3979661-16-bgardon@google.com>
References: <20200925212302.3979661-16-bgardon@google.com>
TO: Ben Gardon <bgardon@google.com>

Hi Ben,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v5.9-rc8 next-20201007]
[cannot apply to kvm/linux-next linux/master vhost/linux-next]
[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/Ben-Gardon/Introduce-the-TDP-MMU/20200926-052649
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 6d28cf7dfede6cfca5119a0d415a6a447c68f3a0
:::::: branch date: 12 days ago
:::::: commit date: 12 days ago
config: x86_64-randconfig-m001-20201008 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0

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

smatch warnings:
arch/x86/kvm/mmu/tdp_mmu.c:756 set_tdp_spte() error: uninitialized symbol 'new_spte'.

vim +/new_spte +756 arch/x86/kvm/mmu/tdp_mmu.c

8753659d94fc330 Ben Gardon 2020-09-25  725  
8753659d94fc330 Ben Gardon 2020-09-25  726  /*
8753659d94fc330 Ben Gardon 2020-09-25  727   * Handle the changed_pte MMU notifier for the TDP MMU.
8753659d94fc330 Ben Gardon 2020-09-25  728   * data is a pointer to the new pte_t mapping the HVA specified by the MMU
8753659d94fc330 Ben Gardon 2020-09-25  729   * notifier.
8753659d94fc330 Ben Gardon 2020-09-25  730   * Returns non-zero if a flush is needed before releasing the MMU lock.
8753659d94fc330 Ben Gardon 2020-09-25  731   */
8753659d94fc330 Ben Gardon 2020-09-25  732  static int set_tdp_spte(struct kvm *kvm, struct kvm_memory_slot *slot,
8753659d94fc330 Ben Gardon 2020-09-25  733  			struct kvm_mmu_page *root, gfn_t gfn, gfn_t unused,
8753659d94fc330 Ben Gardon 2020-09-25  734  			unsigned long data)
8753659d94fc330 Ben Gardon 2020-09-25  735  {
8753659d94fc330 Ben Gardon 2020-09-25  736  	struct tdp_iter iter;
8753659d94fc330 Ben Gardon 2020-09-25  737  	pte_t *ptep = (pte_t *)data;
8753659d94fc330 Ben Gardon 2020-09-25  738  	kvm_pfn_t new_pfn;
8753659d94fc330 Ben Gardon 2020-09-25  739  	u64 new_spte;
8753659d94fc330 Ben Gardon 2020-09-25  740  	int need_flush = 0;
8753659d94fc330 Ben Gardon 2020-09-25  741  	int as_id = kvm_mmu_page_as_id(root);
8753659d94fc330 Ben Gardon 2020-09-25  742  
8753659d94fc330 Ben Gardon 2020-09-25  743  	WARN_ON(pte_huge(*ptep));
8753659d94fc330 Ben Gardon 2020-09-25  744  
8753659d94fc330 Ben Gardon 2020-09-25  745  	new_pfn = pte_pfn(*ptep);
8753659d94fc330 Ben Gardon 2020-09-25  746  
8753659d94fc330 Ben Gardon 2020-09-25  747  	for_each_tdp_pte_root(iter, root, gfn, gfn + 1) {
8753659d94fc330 Ben Gardon 2020-09-25  748  		if (iter.level != PG_LEVEL_4K)
8753659d94fc330 Ben Gardon 2020-09-25  749  			continue;
8753659d94fc330 Ben Gardon 2020-09-25  750  
8753659d94fc330 Ben Gardon 2020-09-25  751  		if (!is_shadow_present_pte(iter.old_spte))
8753659d94fc330 Ben Gardon 2020-09-25  752  			break;
8753659d94fc330 Ben Gardon 2020-09-25  753  
8753659d94fc330 Ben Gardon 2020-09-25  754  		*iter.sptep = 0;
8753659d94fc330 Ben Gardon 2020-09-25  755  		handle_changed_spte(kvm, as_id, iter.gfn, iter.old_spte,
8753659d94fc330 Ben Gardon 2020-09-25 @756  				    new_spte, iter.level);
8753659d94fc330 Ben Gardon 2020-09-25  757  
8753659d94fc330 Ben Gardon 2020-09-25  758  		kvm_flush_remote_tlbs_with_address(kvm, iter.gfn, 1);
8753659d94fc330 Ben Gardon 2020-09-25  759  
8753659d94fc330 Ben Gardon 2020-09-25  760  		if (!pte_write(*ptep)) {
8753659d94fc330 Ben Gardon 2020-09-25  761  			new_spte = kvm_mmu_changed_pte_notifier_make_spte(
8753659d94fc330 Ben Gardon 2020-09-25  762  					iter.old_spte, new_pfn);
8753659d94fc330 Ben Gardon 2020-09-25  763  
8753659d94fc330 Ben Gardon 2020-09-25  764  			*iter.sptep = new_spte;
8753659d94fc330 Ben Gardon 2020-09-25  765  			handle_changed_spte(kvm, as_id, iter.gfn, iter.old_spte,
8753659d94fc330 Ben Gardon 2020-09-25  766  					    new_spte, iter.level);
8753659d94fc330 Ben Gardon 2020-09-25  767  		}
8753659d94fc330 Ben Gardon 2020-09-25  768  
8753659d94fc330 Ben Gardon 2020-09-25  769  		need_flush = 1;
8753659d94fc330 Ben Gardon 2020-09-25  770  	}
8753659d94fc330 Ben Gardon 2020-09-25  771  
8753659d94fc330 Ben Gardon 2020-09-25  772  	if (need_flush)
8753659d94fc330 Ben Gardon 2020-09-25  773  		kvm_flush_remote_tlbs_with_address(kvm, gfn, 1);
8753659d94fc330 Ben Gardon 2020-09-25  774  
8753659d94fc330 Ben Gardon 2020-09-25  775  	return 0;
8753659d94fc330 Ben Gardon 2020-09-25  776  }
8753659d94fc330 Ben Gardon 2020-09-25  777  

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

[-- Attachment #2: config.gz --]
[-- Type: application/gzip, Size: 41414 bytes --]