[PATCH 23/45] KVM: MMU: Extend kvm_mmu_page->slot_bitmap size

Avi Kivity
2008-12-08T11:49:00Z

From: Sheng Yang <sheng@linux.intel.com>

Otherwise set_bit() for private memory slot(above KVM_MEMORY_SLOTS) would
corrupted memory in 32bit host.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
arch/x86/include/asm/kvm_host.h | 8 +++++---
arch/x86/kvm/mmu.c | 6 +++---
2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 93040b5..59c3ae1 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -192,9 +192,11 @@ struct kvm_mmu_page {
u64 *spt;
/* hold the gfn of each spte inside spt */
gfn_t *gfns;
- unsigned long slot_bitmap; /* One bit set per slot which has memory
- * in this shadow page.
- */
+ /*
+ * One bit set per slot which has memory
+ * in this shadow page.
+ */
+ DECLARE_BITMAP(slot_bitmap, KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS);
int multimapped; /* More than one parent_pte? */
int root_count; /* Currently serving as active root */
bool unsync;
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 09d05f5..8687758 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -789,7 +789,7 @@ static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages);
ASSERT(is_empty_shadow_page(sp->spt));
- sp->slot_bitmap = 0;
+ bitmap_zero(sp->slot_bitmap, KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS);
sp->multimapped = 0;
sp->parent_pte = parent_pte;
--vcpu->kvm->arch.n_free_mmu_pages;
@@ -1364,7 +1364,7 @@ static void page_header_update_slot(struct kvm *kvm, void *pte, gfn_t gfn)
int slot = memslot_id(kvm, gfn_to_memslot(kvm, gfn));
struct kvm_mmu_page *sp = page_header(__pa(pte));

- __set_bit(slot, &sp->slot_bitmap);
+ __set_bit(slot, sp->slot_bitmap);
}

static void mmu_convert_notrap(struct kvm_mmu_page *sp)
@@ -2564,7 +2564,7 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
int i;
u64 *pt;

- if (!test_bit(slot, &sp->slot_bitmap))
+ if (!test_bit(slot, sp->slot_bitmap))
continue;

pt = sp->spt;
--
1.6.0.3