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Message-ID: <202506142129.ClBlxdtW-lkp@intel.com>
Date: Sat, 14 Jun 2025 22:03:52 +0800
From: kernel test robot <lkp@...el.com>
To: James Houghton <jthoughton@...gle.com>,
Paolo Bonzini <pbonzini@...hat.com>,
Sean Christopherson <seanjc@...gle.com>
Cc: llvm@...ts.linux.dev, oe-kbuild-all@...ts.linux.dev,
Vipin Sharma <vipinsh@...gle.com>,
David Matlack <dmatlack@...gle.com>,
James Houghton <jthoughton@...gle.com>, kvm@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 3/7] KVM: x86/mmu: Recover TDP MMU NX huge pages using
MMU read lock
Hi James,
kernel test robot noticed the following build errors:
[auto build test ERROR on 8046d29dde17002523f94d3e6e0ebe486ce52166]
url: https://github.com/intel-lab-lkp/linux/commits/James-Houghton/KVM-x86-mmu-Track-TDP-MMU-NX-huge-pages-separately/20250614-042620
base: 8046d29dde17002523f94d3e6e0ebe486ce52166
patch link: https://lore.kernel.org/r/20250613202315.2790592-4-jthoughton%40google.com
patch subject: [PATCH v4 3/7] KVM: x86/mmu: Recover TDP MMU NX huge pages using MMU read lock
config: i386-buildonly-randconfig-003-20250614 (https://download.01.org/0day-ci/archive/20250614/202506142129.ClBlxdtW-lkp@intel.com/config)
compiler: clang version 20.1.2 (https://github.com/llvm/llvm-project 58df0ef89dd64126512e4ee27b4ac3fd8ddf6247)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250614/202506142129.ClBlxdtW-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@...el.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202506142129.ClBlxdtW-lkp@intel.com/
All errors (new ones prefixed by >>):
arch/x86/kvm/mmu/mmu.c:7570:28: error: use of undeclared identifier 'KVM_TDP_MMU'
7570 | bool is_tdp = mmu_type == KVM_TDP_MMU;
| ^
>> arch/x86/kvm/mmu/mmu.c:7594:25: error: no member named 'tdp_mmu_pages_lock' in 'struct kvm_arch'
7594 | spin_lock(&kvm->arch.tdp_mmu_pages_lock);
| ~~~~~~~~~ ^
arch/x86/kvm/mmu/mmu.c:7597:28: error: no member named 'tdp_mmu_pages_lock' in 'struct kvm_arch'
7597 | spin_unlock(&kvm->arch.tdp_mmu_pages_lock);
| ~~~~~~~~~ ^
arch/x86/kvm/mmu/mmu.c:7617:27: error: no member named 'tdp_mmu_pages_lock' in 'struct kvm_arch'
7617 | spin_unlock(&kvm->arch.tdp_mmu_pages_lock);
| ~~~~~~~~~ ^
4 errors generated.
vim +7594 arch/x86/kvm/mmu/mmu.c
7565
7566 static void kvm_recover_nx_huge_pages(struct kvm *kvm,
7567 enum kvm_mmu_type mmu_type)
7568 {
7569 unsigned long to_zap = nx_huge_pages_to_zap(kvm, mmu_type);
> 7570 bool is_tdp = mmu_type == KVM_TDP_MMU;
7571 struct list_head *nx_huge_pages;
7572 struct kvm_mmu_page *sp;
7573 LIST_HEAD(invalid_list);
7574 bool flush = false;
7575 int rcu_idx;
7576
7577 nx_huge_pages = &kvm->arch.possible_nx_huge_pages[mmu_type].pages;
7578
7579 rcu_idx = srcu_read_lock(&kvm->srcu);
7580 if (is_tdp)
7581 read_lock(&kvm->mmu_lock);
7582 else
7583 write_lock(&kvm->mmu_lock);
7584
7585 /*
7586 * Zapping TDP MMU shadow pages, including the remote TLB flush, must
7587 * be done under RCU protection, because the pages are freed via RCU
7588 * callback.
7589 */
7590 rcu_read_lock();
7591
7592 for ( ; to_zap; --to_zap) {
7593 if (is_tdp)
> 7594 spin_lock(&kvm->arch.tdp_mmu_pages_lock);
7595 if (list_empty(nx_huge_pages)) {
7596 if (is_tdp)
7597 spin_unlock(&kvm->arch.tdp_mmu_pages_lock);
7598 break;
7599 }
7600
7601 /*
7602 * We use a separate list instead of just using active_mmu_pages
7603 * because the number of shadow pages that be replaced with an
7604 * NX huge page is expected to be relatively small compared to
7605 * the total number of shadow pages. And because the TDP MMU
7606 * doesn't use active_mmu_pages.
7607 */
7608 sp = list_first_entry(nx_huge_pages,
7609 struct kvm_mmu_page,
7610 possible_nx_huge_page_link);
7611 WARN_ON_ONCE(!sp->nx_huge_page_disallowed);
7612 WARN_ON_ONCE(!sp->role.direct);
7613
7614 unaccount_nx_huge_page(kvm, sp);
7615
7616 if (is_tdp)
7617 spin_unlock(&kvm->arch.tdp_mmu_pages_lock);
7618
7619 /*
7620 * Do not attempt to recover any NX Huge Pages that are being
7621 * dirty tracked, as they would just be faulted back in as 4KiB
7622 * pages. The NX Huge Pages in this slot will be recovered,
7623 * along with all the other huge pages in the slot, when dirty
7624 * logging is disabled.
7625 */
7626 if (!kvm_mmu_sp_dirty_logging_enabled(kvm, sp)) {
7627 if (is_tdp)
7628 flush |= kvm_tdp_mmu_zap_possible_nx_huge_page(kvm, sp);
7629 else
7630 kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list);
7631
7632 }
7633
7634 WARN_ON_ONCE(sp->nx_huge_page_disallowed);
7635
7636 if (need_resched() || rwlock_needbreak(&kvm->mmu_lock)) {
7637 kvm_mmu_remote_flush_or_zap(kvm, &invalid_list, flush);
7638 rcu_read_unlock();
7639
7640 if (is_tdp)
7641 cond_resched_rwlock_read(&kvm->mmu_lock);
7642 else
7643 cond_resched_rwlock_write(&kvm->mmu_lock);
7644
7645 flush = false;
7646 rcu_read_lock();
7647 }
7648 }
7649 kvm_mmu_remote_flush_or_zap(kvm, &invalid_list, flush);
7650
7651 rcu_read_unlock();
7652
7653 if (is_tdp)
7654 read_unlock(&kvm->mmu_lock);
7655 else
7656 write_unlock(&kvm->mmu_lock);
7657 srcu_read_unlock(&kvm->srcu, rcu_idx);
7658 }
7659
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
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