Commit 54987b7a authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

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: default avatarValentine Sinitsyn <valentine.sinitsyn@gmail.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent ef54bcfe

arch/x86/include/asm/kvm_host.h

+6 −3
Original line number Diff line number Diff line
@@ -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;

}

arch/x86/kvm/mmu.c

+1 −1
Original line number Diff line number Diff line
@@ -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)

arch/x86/kvm/paging_tmpl.h

+4 −3
Original line number Diff line number Diff line
@@ -321,7 +321,8 @@ retry_walk: 
		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 @@ retry_walk: 
		 * fields.

		 */

		if (unlikely(real_gfn == UNMAPPED_GVA))

			goto error;

			return 0;



		real_gfn = gpa_to_gfn(real_gfn);
@@ -376,7 +377,7 @@ retry_walk: 
	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;

arch/x86/kvm/x86.c

+5 −4
Original line number Diff line number Diff line
@@ -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;

}

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