diff options
| author | Roedel, Joerg <Joerg.Roedel@amd.com> | 2011-04-20 15:33:16 +0200 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2011-05-22 08:39:26 -0400 |
| commit | a78484c60e35555d6e0e5b1eb83d4913621c59fb (patch) | |
| tree | ca0c7ec1e95aa3b6087ae0191a19fa1e0d4ca6b0 /arch/x86/kvm | |
| parent | 13db70eca62c5bbb2cbbf6b23dadb94065d363d1 (diff) | |
| download | linux-a78484c60e35555d6e0e5b1eb83d4913621c59fb.tar.bz2 | |
KVM: MMU: Make cmpxchg_gpte aware of nesting too
This patch makes the cmpxchg_gpte() function aware of the
difference between l1-gfns and l2-gfns when nested
virtualization is in use. This fixes a potential
data-corruption problem in the l1-guest and makes the code
work correct (at least as correct as the hardware which is
emulated in this code) again.
Cc: stable@kernel.org
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
| -rw-r--r-- | arch/x86/kvm/paging_tmpl.h | 30 |
1 files changed, 23 insertions, 7 deletions
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 74f8567d57ac..1b6899088f97 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -78,15 +78,21 @@ static gfn_t gpte_to_gfn_lvl(pt_element_t gpte, int lvl) return (gpte & PT_LVL_ADDR_MASK(lvl)) >> PAGE_SHIFT; } -static bool FNAME(cmpxchg_gpte)(struct kvm *kvm, +static int FNAME(cmpxchg_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, gfn_t table_gfn, unsigned index, pt_element_t orig_pte, pt_element_t new_pte) { pt_element_t ret; pt_element_t *table; struct page *page; + gpa_t gpa; - page = gfn_to_page(kvm, table_gfn); + gpa = mmu->translate_gpa(vcpu, table_gfn << PAGE_SHIFT, + PFERR_USER_MASK|PFERR_WRITE_MASK); + if (gpa == UNMAPPED_GVA) + return -EFAULT; + + page = gfn_to_page(vcpu->kvm, gpa_to_gfn(gpa)); table = kmap_atomic(page, KM_USER0); ret = CMPXCHG(&table[index], orig_pte, new_pte); @@ -192,11 +198,17 @@ walk: #endif if (!eperm && !rsvd_fault && !(pte & PT_ACCESSED_MASK)) { + int ret; trace_kvm_mmu_set_accessed_bit(table_gfn, index, sizeof(pte)); - if (FNAME(cmpxchg_gpte)(vcpu->kvm, table_gfn, - index, pte, pte|PT_ACCESSED_MASK)) + ret = FNAME(cmpxchg_gpte)(vcpu, mmu, table_gfn, + index, pte, pte|PT_ACCESSED_MASK); + if (ret < 0) { + present = false; + break; + } else if (ret) goto walk; + mark_page_dirty(vcpu->kvm, table_gfn); pte |= PT_ACCESSED_MASK; } @@ -245,13 +257,17 @@ walk: goto error; if (write_fault && !is_dirty_gpte(pte)) { - bool ret; + int ret; trace_kvm_mmu_set_dirty_bit(table_gfn, index, sizeof(pte)); - ret = FNAME(cmpxchg_gpte)(vcpu->kvm, table_gfn, index, pte, + ret = FNAME(cmpxchg_gpte)(vcpu, mmu, table_gfn, index, pte, pte|PT_DIRTY_MASK); - if (ret) + if (ret < 0) { + present = false; + goto error; + } else if (ret) goto walk; + mark_page_dirty(vcpu->kvm, table_gfn); pte |= PT_DIRTY_MASK; walker->ptes[walker->level - 1] = pte; |