KVM: MMU: Extend kvm_mmu_page->slot_bitmap size

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>

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 93040b5eed96..59c3ae10de6c 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 09d05f57bf66..8687758b5295 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;