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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 <valentine.sinitsyn@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2014-09-02 13:23:06 +02:00
parent ef54bcfeea
commit 54987b7afa
4 changed files with 16 additions and 11 deletions
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9
arch/x86/include/asm/kvm_host.h
View File

@ -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;
}

2
arch/x86/kvm/mmu.c
View File

@ -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)

7
arch/x86/kvm/paging_tmpl.h
View File

@ -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;

9
arch/x86/kvm/x86.c
View File

@ -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;
}