diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/mmu/mmu.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index c04e30f6e0db..e7bac871747c 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -3588,6 +3588,7 @@ out_unlock: static int mmu_alloc_special_roots(struct kvm_vcpu *vcpu) { struct kvm_mmu *mmu = vcpu->arch.mmu; + bool need_pml5 = mmu->shadow_root_level > PT64_ROOT_4LEVEL; u64 *pml5_root = NULL; u64 *pml4_root = NULL; u64 *pae_root; @@ -3602,7 +3603,14 @@ static int mmu_alloc_special_roots(struct kvm_vcpu *vcpu) mmu->shadow_root_level < PT64_ROOT_4LEVEL) return 0; - if (mmu->pae_root && mmu->pml4_root && mmu->pml5_root) + /* + * NPT, the only paging mode that uses this horror, uses a fixed number + * of levels for the shadow page tables, e.g. all MMUs are 4-level or + * all MMus are 5-level. Thus, this can safely require that pml5_root + * is allocated if the other roots are valid and pml5 is needed, as any + * prior MMU would also have required pml5. + */ + if (mmu->pae_root && mmu->pml4_root && (!need_pml5 || mmu->pml5_root)) return 0; /* @@ -3610,7 +3618,7 @@ static int mmu_alloc_special_roots(struct kvm_vcpu *vcpu) * bail if KVM ends up in a state where only one of the roots is valid. */ if (WARN_ON_ONCE(!tdp_enabled || mmu->pae_root || mmu->pml4_root || - mmu->pml5_root)) + (need_pml5 && mmu->pml5_root))) return -EIO; /* @@ -3626,7 +3634,7 @@ static int mmu_alloc_special_roots(struct kvm_vcpu *vcpu) if (!pml4_root) goto err_pml4; - if (mmu->shadow_root_level > PT64_ROOT_4LEVEL) { + if (need_pml5) { pml5_root = (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT); if (!pml5_root) goto err_pml5; |