KVM: Add method to check for backwards-compatible API extensions

[cascardo/linux.git] / drivers / kvm / mmu.c

diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index 2cb4893..2d90577 100644 (file)
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -131,7 +131,7 @@ static int dbg = 1;
        (((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1))
 
 
-#define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & PAGE_MASK)
+#define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1))
 #define PT64_DIR_BASE_ADDR_MASK \
        (PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1))
 
@@ -406,8 +406,8 @@ static void rmap_write_protect(struct kvm_vcpu *vcpu, u64 gfn)
                        spte = desc->shadow_ptes[0];
                }
                BUG_ON(!spte);
-               BUG_ON((*spte & PT64_BASE_ADDR_MASK) !=
-                      page_to_pfn(page) << PAGE_SHIFT);
+               BUG_ON((*spte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT
+                      != page_to_pfn(page));
                BUG_ON(!(*spte & PT_PRESENT_MASK));
                BUG_ON(!(*spte & PT_WRITABLE_MASK));
                rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
@@ -1171,6 +1171,7 @@ void kvm_mmu_pre_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes)
                         * and zap two pdes instead of one.
                         */
                        if (level == PT32_ROOT_LEVEL) {
+                               page_offset &= ~7; /* kill rounding error */
                                page_offset <<= 1;
                                npte = 2;
                        }
@@ -1359,7 +1360,7 @@ static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
 
 static void audit_mappings(struct kvm_vcpu *vcpu)
 {
-       int i;
+       unsigned i;
 
        if (vcpu->mmu.root_level == 4)
                audit_mappings_page(vcpu, vcpu->mmu.root_hpa, 0, 4);