Commit 80b63faf authored Aug 24, 2010 by Xiaotian Feng Committed by Avi Kivity Oct 24, 2010

KVM: MMU: fix regression from rework mmu_shrink() code



Latest kvm mmu_shrink code rework makes kernel changes kvm->arch.n_used_mmu_pages/
kvm->arch.n_max_mmu_pages at kvm_mmu_free_page/kvm_mmu_alloc_page, which is called
by kvm_mmu_commit_zap_page. So the kvm->arch.n_used_mmu_pages or
kvm_mmu_available_pages(vcpu->kvm) is unchanged after kvm_mmu_prepare_zap_page(),
This caused kvm_mmu_change_mmu_pages/__kvm_mmu_free_some_pages loops forever.
Moving kvm_mmu_commit_zap_page would make the while loop performs as normal.

Reported-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Tested-by: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Tim Pepper <lnxninja@linux.vnet.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

parent e4abac67

arch/x86/kvm/mmu.c

+3 −4

Original line number	Diff line number	Diff line
		@@ -1720,10 +1720,9 @@ void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int goal_nr_mmu_pages)

		page = container_of(kvm->arch.active_mmu_pages.prev,
		struct kvm_mmu_page, link);
		kvm_mmu_prepare_zap_page(kvm, page,
		&invalid_list);
		}
		kvm_mmu_prepare_zap_page(kvm, page, &invalid_list);
		kvm_mmu_commit_zap_page(kvm, &invalid_list);
		}
		goal_nr_mmu_pages = kvm->arch.n_used_mmu_pages;
		}

		@@ -2972,9 +2971,9 @@ void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
		sp = container_of(vcpu->kvm->arch.active_mmu_pages.prev,
		struct kvm_mmu_page, link);
		kvm_mmu_prepare_zap_page(vcpu->kvm, sp, &invalid_list);
		kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
		++vcpu->kvm->stat.mmu_recycled;
		}
		kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
		}

		int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code)

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