linux-kernel - [PATCH 1/2] KVM: x86/mmu: Wrap kvm_mmu_zap_all

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Date:   Mon, 19 Apr 2021 11:37:41 -0700
From:   Ben Gardon <bgardon@...gle.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>, Peter Xu <peterx@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Robert Hu <robert.hu@...el.com>,
        Farrah Chen <farrah.chen@...el.com>,
        Danmei Wei <danmei.wei@...el.com>,
        Ben Gardon <bgardon@...gle.com>,
        kernel test robot <lkp@...el.com>
Subject: [PATCH 1/2] KVM: x86/mmu: Wrap kvm_mmu_zap_all_fast TDP MMU code in ifdefs

The TDP MMU code in kvm_mmu_zap_all_fast is only needed with
CONFIG_X86_64 and creates a build error without that setting. Since the
TDP MMU can only be enabled with CONFIG_X86_64, wrap those code blocks
in ifdefs.

Fixes: 1336c692abad ("KVM: x86/mmu: Fast invalidation for TDP MMU")

Reported-by: kernel test robot <lkp@...el.com>
Signed-off-by: Ben Gardon <bgardon@...gle.com>
---
 arch/x86/kvm/mmu/mmu.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 0f311c9bf9c6..3ae59c8e129b 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5407,7 +5407,9 @@ static void kvm_zap_obsolete_pages(struct kvm *kvm)
  */
 static void kvm_mmu_zap_all_fast(struct kvm *kvm)
 {
+#ifdef CONFIG_X86_64
 	struct kvm_mmu_page *root;
+#endif /* CONFIG_X86_64 */
 
 	lockdep_assert_held(&kvm->slots_lock);
 
@@ -5424,6 +5426,7 @@ static void kvm_mmu_zap_all_fast(struct kvm *kvm)
 	kvm->arch.mmu_valid_gen = kvm->arch.mmu_valid_gen ? 0 : 1;
 
 
+#ifdef CONFIG_X86_64
 	if (is_tdp_mmu_enabled(kvm)) {
 		/*
 		 * Mark each TDP MMU root as invalid so that other threads
@@ -5456,6 +5459,7 @@ static void kvm_mmu_zap_all_fast(struct kvm *kvm)
 			if (refcount_inc_not_zero(&root->tdp_mmu_root_count))
 				root->role.invalid = true;
 	}
+#endif /* CONFIG_X86_64 */
 
 	/*
 	 * Notify all vcpus to reload its shadow page table and flush TLB.
@@ -5471,11 +5475,13 @@ static void kvm_mmu_zap_all_fast(struct kvm *kvm)
 
 	write_unlock(&kvm->mmu_lock);
 
+#ifdef CONFIG_X86_64
 	if (is_tdp_mmu_enabled(kvm)) {
 		read_lock(&kvm->mmu_lock);
 		kvm_tdp_mmu_zap_invalidated_roots(kvm);
 		read_unlock(&kvm->mmu_lock);
 	}
+#endif /* CONFIG_X86_64 */
 }
 
 static bool kvm_has_zapped_obsolete_pages(struct kvm *kvm)
-- 
2.31.1.368.gbe11c130af-goog