From 54987b7afa902e886b3a751c056c2a4d4701020e Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Tue, 2 Sep 2014 13:23:06 +0200 Subject: [PATCH] KVM: x86: propagate exception from permission checks on the nested page fault Currently, if a permission error happens during the translation of the final GPA to HPA, walk_addr_generic returns 0 but does not fill in walker->fault. To avoid this, add an x86_exception* argument to the translate_gpa function, and let it fill in walker->fault. The nested_page_fault field will be true, since the walk_mmu is the nested_mmu and translate_gpu instead operates on the "outer" (NPT) instance. Reported-by: Valentine Sinitsyn Signed-off-by: Paolo Bonzini --- arch/x86/include/asm/kvm_host.h | 9 ++++++--- arch/x86/kvm/mmu.c | 2 +- arch/x86/kvm/paging_tmpl.h | 7 ++++--- arch/x86/kvm/x86.c | 9 +++++---- 4 files changed, 16 insertions(+), 11 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index c9896518e54d..2dbde3b7446c 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -262,7 +262,8 @@ struct kvm_mmu { struct x86_exception *fault); gpa_t (*gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t gva, u32 access, struct x86_exception *exception); - gpa_t (*translate_gpa)(struct kvm_vcpu *vcpu, gpa_t gpa, u32 access); + gpa_t (*translate_gpa)(struct kvm_vcpu *vcpu, gpa_t gpa, u32 access, + struct x86_exception *exception); int (*sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp); void (*invlpg)(struct kvm_vcpu *vcpu, gva_t gva); @@ -923,7 +924,8 @@ void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu); int kvm_mmu_load(struct kvm_vcpu *vcpu); void kvm_mmu_unload(struct kvm_vcpu *vcpu); void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu); -gpa_t translate_nested_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u32 access); +gpa_t translate_nested_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u32 access, + struct x86_exception *exception); gpa_t kvm_mmu_gva_to_gpa_read(struct kvm_vcpu *vcpu, gva_t gva, struct x86_exception *exception); gpa_t kvm_mmu_gva_to_gpa_fetch(struct kvm_vcpu *vcpu, gva_t gva, @@ -943,7 +945,8 @@ void kvm_mmu_new_cr3(struct kvm_vcpu *vcpu); void kvm_enable_tdp(void); void kvm_disable_tdp(void); -static inline gpa_t translate_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u32 access) +static inline gpa_t translate_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u32 access, + struct x86_exception *exception) { return gpa; } diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 5b93a597e0c8..76398fe15df2 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -3200,7 +3200,7 @@ static gpa_t nonpaging_gva_to_gpa_nested(struct kvm_vcpu *vcpu, gva_t vaddr, { if (exception) exception->error_code = 0; - return vcpu->arch.nested_mmu.translate_gpa(vcpu, vaddr, access); + return vcpu->arch.nested_mmu.translate_gpa(vcpu, vaddr, access, exception); } static bool quickly_check_mmio_pf(struct kvm_vcpu *vcpu, u64 addr, bool direct) diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index df1a044d92de..0ab6c65a2821 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -321,7 +321,8 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker, walker->pte_gpa[walker->level - 1] = pte_gpa; real_gfn = mmu->translate_gpa(vcpu, gfn_to_gpa(table_gfn), - PFERR_USER_MASK|PFERR_WRITE_MASK); + PFERR_USER_MASK|PFERR_WRITE_MASK, + &walker->fault); /* * FIXME: This can happen if emulation (for of an INS/OUTS @@ -334,7 +335,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker, * fields. */ if (unlikely(real_gfn == UNMAPPED_GVA)) - goto error; + return 0; real_gfn = gpa_to_gfn(real_gfn); @@ -376,7 +377,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker, if (PTTYPE == 32 && walker->level == PT_DIRECTORY_LEVEL && is_cpuid_PSE36()) gfn += pse36_gfn_delta(pte); - real_gpa = mmu->translate_gpa(vcpu, gfn_to_gpa(gfn), access); + real_gpa = mmu->translate_gpa(vcpu, gfn_to_gpa(gfn), access, &walker->fault); if (real_gpa == UNMAPPED_GVA) return 0; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 354194671902..7b25aa2725f8 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -459,11 +459,12 @@ int kvm_read_guest_page_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, gfn_t ngfn, void *data, int offset, int len, u32 access) { + struct x86_exception exception; gfn_t real_gfn; gpa_t ngpa; ngpa = gfn_to_gpa(ngfn); - real_gfn = mmu->translate_gpa(vcpu, ngpa, access); + real_gfn = mmu->translate_gpa(vcpu, ngpa, access, &exception); if (real_gfn == UNMAPPED_GVA) return -EFAULT; @@ -4065,16 +4066,16 @@ void kvm_get_segment(struct kvm_vcpu *vcpu, kvm_x86_ops->get_segment(vcpu, var, seg); } -gpa_t translate_nested_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u32 access) +gpa_t translate_nested_gpa(struct kvm_vcpu *vcpu, gpa_t gpa, u32 access, + struct x86_exception *exception) { gpa_t t_gpa; - struct x86_exception exception; BUG_ON(!mmu_is_nested(vcpu)); /* NPT walks are always user-walks */ access |= PFERR_USER_MASK; - t_gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gpa, access, &exception); + t_gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gpa, access, exception); return t_gpa; } -- 2.45.2