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| author | Sean Christopherson <seanjc@google.com> | 2021-03-09 14:42:06 -0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-03-15 04:44:07 -0400 |
| commit | c834e5e44fc15acd4e8a894d462535021c80533e (patch) | |
| tree | 417ff8cf6f3c85b680ecd4bc97e1269f3a690c4d /arch/x86/kvm/mmu/mmu.c | |
| parent | 978c834a669160e9794c551ee324286ebeb414c0 (diff) | |
| download | lwn-c834e5e44fc15acd4e8a894d462535021c80533e.tar.gz lwn-c834e5e44fc15acd4e8a894d462535021c80533e.zip | |
KVM: x86/mmu: Use '0' as the one and only value for an invalid PAE root
Use '0' to denote an invalid pae_root instead of '0' or INVALID_PAGE.
Unlike root_hpa, the pae_roots hold permission bits and thus are
guaranteed to be non-zero. Having to deal with both values leads to
bugs, e.g. failing to set back to INVALID_PAGE, warning on the wrong
value, etc...
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210309224207.1218275-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/mmu/mmu.c')
| -rw-r--r-- | arch/x86/kvm/mmu/mmu.c | 24 |
1 files changed, 13 insertions, 11 deletions
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index febe71935bb5..6b0576ff2846 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -3197,11 +3197,14 @@ void kvm_mmu_free_roots(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, (mmu->root_level >= PT64_ROOT_4LEVEL || mmu->direct_map)) { mmu_free_root_page(kvm, &mmu->root_hpa, &invalid_list); } else if (mmu->pae_root) { - for (i = 0; i < 4; ++i) - if (mmu->pae_root[i] != 0) - mmu_free_root_page(kvm, - &mmu->pae_root[i], - &invalid_list); + for (i = 0; i < 4; ++i) { + if (!IS_VALID_PAE_ROOT(mmu->pae_root[i])) + continue; + + mmu_free_root_page(kvm, &mmu->pae_root[i], + &invalid_list); + mmu->pae_root[i] = INVALID_PAE_ROOT; + } } mmu->root_hpa = INVALID_PAGE; mmu->root_pgd = 0; @@ -3253,8 +3256,7 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu) return -EIO; for (i = 0; i < 4; ++i) { - WARN_ON_ONCE(mmu->pae_root[i] && - VALID_PAGE(mmu->pae_root[i])); + WARN_ON_ONCE(IS_VALID_PAE_ROOT(mmu->pae_root[i])); root = mmu_alloc_root(vcpu, i << (30 - PAGE_SHIFT), i << 30, PT32_ROOT_LEVEL, true); @@ -3328,11 +3330,11 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu) } for (i = 0; i < 4; ++i) { - WARN_ON_ONCE(mmu->pae_root[i] && VALID_PAGE(mmu->pae_root[i])); + WARN_ON_ONCE(IS_VALID_PAE_ROOT(mmu->pae_root[i])); if (mmu->root_level == PT32E_ROOT_LEVEL) { if (!(pdptrs[i] & PT_PRESENT_MASK)) { - mmu->pae_root[i] = 0; + mmu->pae_root[i] = INVALID_PAE_ROOT; continue; } root_gfn = pdptrs[i] >> PAGE_SHIFT; @@ -3450,7 +3452,7 @@ void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu) for (i = 0; i < 4; ++i) { hpa_t root = vcpu->arch.mmu->pae_root[i]; - if (root && VALID_PAGE(root)) { + if (IS_VALID_PAE_ROOT(root)) { root &= PT64_BASE_ADDR_MASK; sp = to_shadow_page(root); mmu_sync_children(vcpu, sp); @@ -5307,7 +5309,7 @@ static int __kvm_mmu_create(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu) mmu->pae_root = page_address(page); for (i = 0; i < 4; ++i) - mmu->pae_root[i] = INVALID_PAGE; + mmu->pae_root[i] = INVALID_PAE_ROOT; return 0; } |