From 83b20b28c670868bfb717be4fe1557c925a81657 Mon Sep 17 00:00:00 2001 From: Wei Yang Date: Fri, 7 Sep 2018 19:59:47 +0800 Subject: [PATCH] KVM: x86: don't reset root in kvm_mmu_setup() Here is the code path which shows kvm_mmu_setup() is invoked after kvm_mmu_create(). Since kvm_mmu_setup() is only invoked in this code path, this means the root_hpa and prev_roots are guaranteed to be invalid. And it is not necessary to reset it again. kvm_vm_ioctl_create_vcpu() kvm_arch_vcpu_create() vmx_create_vcpu() kvm_vcpu_init() kvm_arch_vcpu_init() kvm_mmu_create() kvm_arch_vcpu_setup() kvm_mmu_setup() kvm_init_mmu() This patch set reset_roots to false in kmv_mmu_setup(). Fixes: 50c28f21d045dde8c52548f8482d456b3f0956f5 Signed-off-by: Wei Yang Reviewed-by: Liran Alon Signed-off-by: Paolo Bonzini --- arch/x86/kvm/mmu.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index e24ea7067373..5402c53a079b 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -5417,7 +5417,12 @@ void kvm_mmu_setup(struct kvm_vcpu *vcpu) { MMU_WARN_ON(VALID_PAGE(vcpu->arch.mmu.root_hpa)); - kvm_init_mmu(vcpu, true); + /* + * kvm_mmu_setup() is called only on vCPU initialization. + * Therefore, no need to reset mmu roots as they are not yet + * initialized. + */ + kvm_init_mmu(vcpu, false); } static void kvm_mmu_invalidate_zap_pages_in_memslot(struct kvm *kvm,