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KVM can use them to read all the information that is needed for a nested vmentry or vmexit, and fault out to userspace is needed, prior to committing to completing the vmentry/vmexit. Signed-off-by: Paolo Bonzini --- arch/x86/kvm/regs.c | 51 ++++++++++++++++++++++++++++++++------------- arch/x86/kvm/regs.h | 3 +++ 2 files changed, 40 insertions(+), 14 deletions(-) diff --git a/arch/x86/kvm/regs.c b/arch/x86/kvm/regs.c index 3a11a6d06889..17e5aeb746ef 100644 --- a/arch/x86/kvm/regs.c +++ b/arch/x86/kvm/regs.c @@ -149,17 +149,29 @@ static inline u64 pdptr_rsvd_bits(struct kvm_vcpu *vcpu) return vcpu->arch.reserved_gpa_bits | rsvd_bits(5, 8) | rsvd_bits(1, 2); } +int kvm_validate_pdptrs(struct kvm_vcpu *vcpu, const u64 *pdptrs) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(vcpu->arch.pdptrs); ++i) { + if ((pdptrs[i] & PT_PRESENT_MASK) && + (pdptrs[i] & pdptr_rsvd_bits(vcpu))) + return 0; + } + return 1; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_validate_pdptrs); + /* - * Load the pae pdptrs. Return 1 if they are all valid, 0 otherwise. + * Read the PAE PDPTRs into @pdptrs. Return 1 if they are valid, 0 if they are + * invalid, and a negative value on error. */ -int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3) +int kvm_read_validate_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3, u64 *pdptrs) { struct kvm_pagewalk *w = &vcpu->arch.gva_walk; gfn_t pdpt_gfn = cr3 >> PAGE_SHIFT; gpa_t real_gpa; - int i; int ret; - u64 pdpte[ARRAY_SIZE(vcpu->arch.pdptrs)]; /* * If the MMU is nested, CR3 holds an L2 GPA and needs to be translated @@ -174,8 +186,8 @@ int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3) return 0; /* Note the offset, PDPTRs are 32 byte aligned when using PAE paging. */ - ret = kvm_vcpu_read_guest_page(vcpu, gpa_to_gfn(real_gpa), pdpte, - cr3 & GENMASK(11, 5), sizeof(pdpte)); + ret = kvm_vcpu_read_guest_page(vcpu, gpa_to_gfn(real_gpa), pdptrs, + cr3 & GENMASK(11, 5), sizeof(vcpu->arch.pdptrs)); if (ret == -EFAULT) { kvm_prepare_memory_fault_exit(vcpu, real_gpa & PAGE_MASK, PAGE_SIZE, false, false, false); @@ -184,26 +196,37 @@ int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3) if (ret) return 0; - for (i = 0; i < ARRAY_SIZE(pdpte); ++i) { - if ((pdpte[i] & PT_PRESENT_MASK) && - (pdpte[i] & pdptr_rsvd_bits(vcpu))) { - return 0; - } - } + return kvm_validate_pdptrs(vcpu, pdptrs); +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_read_validate_pdptrs); +void kvm_commit_pdptrs(struct kvm_vcpu *vcpu, const u64 *pdptrs) +{ /* * Marking VCPU_REG_PDPTR dirty doesn't work for !tdp_enabled. * Shadow page roots need to be reconstructed instead. */ - if (!tdp_enabled && memcmp(vcpu->arch.pdptrs, pdpte, sizeof(vcpu->arch.pdptrs))) + if (!tdp_enabled && memcmp(vcpu->arch.pdptrs, pdptrs, sizeof(vcpu->arch.pdptrs))) kvm_mmu_free_roots(vcpu->kvm, &vcpu->arch.root_mmu, KVM_MMU_ROOT_CURRENT); - memcpy(vcpu->arch.pdptrs, pdpte, sizeof(vcpu->arch.pdptrs)); + memcpy(vcpu->arch.pdptrs, pdptrs, sizeof(vcpu->arch.pdptrs)); kvm_register_mark_dirty(vcpu, VCPU_REG_PDPTR); kvm_make_request(KVM_REQ_LOAD_MMU_PGD, vcpu); vcpu->arch.pdptrs_from_userspace = false; +} +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_commit_pdptrs); +int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3) +{ + u64 pdptrs[ARRAY_SIZE(vcpu->arch.pdptrs)]; + int r; + + r = kvm_read_validate_pdptrs(vcpu, cr3, pdptrs); + if (r <= 0) + return r; + + kvm_commit_pdptrs(vcpu, pdptrs); return 1; } EXPORT_SYMBOL_FOR_KVM_INTERNAL(load_pdptrs); diff --git a/arch/x86/kvm/regs.h b/arch/x86/kvm/regs.h index 31f4d3f6ea42..86a92a877374 100644 --- a/arch/x86/kvm/regs.h +++ b/arch/x86/kvm/regs.h @@ -63,6 +63,9 @@ unsigned long kvm_get_dr(struct kvm_vcpu *vcpu, int dr); unsigned long kvm_get_dr6_fixed_1(struct kvm_vcpu *vcpu); unsigned long kvm_get_cr8(struct kvm_vcpu *vcpu); void kvm_lmsw(struct kvm_vcpu *vcpu, unsigned long msw); +int kvm_read_validate_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3, u64 *pdptrs); +int kvm_validate_pdptrs(struct kvm_vcpu *vcpu, const u64 *pdptrs); +void kvm_commit_pdptrs(struct kvm_vcpu *vcpu, const u64 *pdptrs); int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3); static inline bool is_long_mode(struct kvm_vcpu *vcpu) -- 2.52.0