KVM: mmu: allow page tables to be in read-only slots

[karo-tx-linux.git] / virt / kvm / kvm_main.c

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index bf040c4e02b332b7dd2126ae6ed2013261ecfdb4..979bff485fb0b343cb5e1fd4328d7cf046dafef7 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1058,11 +1058,15 @@ unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
 EXPORT_SYMBOL_GPL(gfn_to_hva);
 
 /*
- * The hva returned by this function is only allowed to be read.
- * It should pair with kvm_read_hva() or kvm_read_hva_atomic().
+ * If writable is set to false, the hva returned by this function is only
+ * allowed to be read.
  */
-static unsigned long gfn_to_hva_read(struct kvm *kvm, gfn_t gfn)
+unsigned long gfn_to_hva_prot(struct kvm *kvm, gfn_t gfn, bool *writable)
 {
+       struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
+       if (writable)
+               *writable = !memslot_is_readonly(slot);
+
        return __gfn_to_hva_many(gfn_to_memslot(kvm, gfn), gfn, NULL, false);
 }
 
@@ -1430,7 +1434,7 @@ int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset,
        int r;
        unsigned long addr;
 
-       addr = gfn_to_hva_read(kvm, gfn);
+       addr = gfn_to_hva_prot(kvm, gfn, NULL);
        if (kvm_is_error_hva(addr))
                return -EFAULT;
        r = kvm_read_hva(data, (void __user *)addr + offset, len);
@@ -1468,7 +1472,7 @@ int kvm_read_guest_atomic(struct kvm *kvm, gpa_t gpa, void *data,
        gfn_t gfn = gpa >> PAGE_SHIFT;
        int offset = offset_in_page(gpa);
 
-       addr = gfn_to_hva_read(kvm, gfn);
+       addr = gfn_to_hva_prot(kvm, gfn, NULL);
        if (kvm_is_error_hva(addr))
                return -EFAULT;
        pagefault_disable();