kvm: selftest: add dirty logging test

Test KVM dirty logging functionality.

The test creates a standalone memory slot to test tracking the dirty
pages since we can't really write to the default memory slot which still
contains the guest ELF image.

We have two threads running during the test:

(1) the vcpu thread continuously dirties random guest pages by writting
    a iteration number to the first 8 bytes of the page

(2) the host thread continuously fetches dirty logs for the testing
    memory region and verify each single bit of the dirty bitmap by
    checking against the values written onto the page

Note that since the guest cannot calls the general userspace APIs like
random(), it depends on the host to provide random numbers for the
page indexes to dirty.

Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 43 insertions, 0 deletions

diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index fa61afffcc8d..e9ba389c48db 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -169,6 +169,16 @@ void kvm_vm_restart(struct kvm_vm *vmp, int perm)
 	}
 }
 
+void kvm_vm_get_dirty_log(struct kvm_vm *vm, int slot, void *log)
+{
+	struct kvm_dirty_log args = { .dirty_bitmap = log, .slot = slot };
+	int ret;
+
+	ret = ioctl(vm->fd, KVM_GET_DIRTY_LOG, &args);
+	TEST_ASSERT(ret == 0, "%s: KVM_GET_DIRTY_LOG failed: %s",
+		    strerror(-ret));
+}
+
 /* Userspace Memory Region Find
  *
  * Input Args:
@@ -924,6 +934,39 @@ vm_vaddr_t vm_vaddr_alloc(struct kvm_vm *vm, size_t sz, vm_vaddr_t vaddr_min,
 	return vaddr_start;
 }
 
+/*
+ * Map a range of VM virtual address to the VM's physical address
+ *
+ * Input Args:
+ *   vm - Virtual Machine
+ *   vaddr - Virtuall address to map
+ *   paddr - VM Physical Address
+ *   size - The size of the range to map
+ *   pgd_memslot - Memory region slot for new virtual translation tables
+ *
+ * Output Args: None
+ *
+ * Return: None
+ *
+ * Within the VM given by vm, creates a virtual translation for the
+ * page range starting at vaddr to the page range starting at paddr.
+ */
+void virt_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr,
+	      size_t size, uint32_t pgd_memslot)
+{
+	size_t page_size = vm->page_size;
+	size_t npages = size / page_size;
+
+	TEST_ASSERT(vaddr + size > vaddr, "Vaddr overflow");
+	TEST_ASSERT(paddr + size > paddr, "Paddr overflow");
+
+	while (npages--) {
+		virt_pg_map(vm, vaddr, paddr, pgd_memslot);
+		vaddr += page_size;
+		paddr += page_size;
+	}
+}
+
 /* Address VM Physical to Host Virtual
  *
  * Input Args: