selftests: kvm: add test for dirty logging inside nested guests

Check that accesses by nested guests are logged according to the
L1 physical addresses rather than L2.

Most of the patch is really adding EPT support to the testing
framework.

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

1 files changed, 156 insertions, 0 deletions

diff --git a/tools/testing/selftests/kvm/x86_64/vmx_dirty_log_test.c b/tools/testing/selftests/kvm/x86_64/vmx_dirty_log_test.c
new file mode 100644
index 000000000000..0bca1cfe2c1e
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/vmx_dirty_log_test.c
@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KVM dirty page logging test
+ *
+ * Copyright (C) 2018, Red Hat, Inc.
+ */
+
+#define _GNU_SOURCE /* for program_invocation_name */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
+
+#include "test_util.h"
+#include "kvm_util.h"
+#include "processor.h"
+#include "vmx.h"
+
+#define VCPU_ID				1
+
+/* The memory slot index to track dirty pages */
+#define TEST_MEM_SLOT_INDEX		1
+#define TEST_MEM_SIZE			3
+
+/* L1 guest test virtual memory offset */
+#define GUEST_TEST_MEM			0xc0000000
+
+/* L2 guest test virtual memory offset */
+#define NESTED_TEST_MEM1		0xc0001000
+#define NESTED_TEST_MEM2		0xc0002000
+
+static void l2_guest_code(void)
+{
+	*(volatile uint64_t *)NESTED_TEST_MEM1;
+	*(volatile uint64_t *)NESTED_TEST_MEM1 = 1;
+	GUEST_SYNC(true);
+	GUEST_SYNC(false);
+
+	*(volatile uint64_t *)NESTED_TEST_MEM2 = 1;
+	GUEST_SYNC(true);
+	*(volatile uint64_t *)NESTED_TEST_MEM2 = 1;
+	GUEST_SYNC(true);
+	GUEST_SYNC(false);
+
+	/* Exit to L1 and never come back.  */
+	vmcall();
+}
+
+void l1_guest_code(struct vmx_pages *vmx)
+{
+#define L2_GUEST_STACK_SIZE 64
+	unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
+
+	GUEST_ASSERT(vmx->vmcs_gpa);
+	GUEST_ASSERT(prepare_for_vmx_operation(vmx));
+	GUEST_ASSERT(load_vmcs(vmx));
+
+	prepare_vmcs(vmx, l2_guest_code,
+		     &l2_guest_stack[L2_GUEST_STACK_SIZE]);
+
+	GUEST_SYNC(false);
+	GUEST_ASSERT(!vmlaunch());
+	GUEST_SYNC(false);
+	GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
+	GUEST_DONE();
+}
+
+int main(int argc, char *argv[])
+{
+	vm_vaddr_t vmx_pages_gva = 0;
+	struct vmx_pages *vmx;
+	unsigned long *bmap;
+	uint64_t *host_test_mem;
+
+	struct kvm_vm *vm;
+	struct kvm_run *run;
+	struct ucall uc;
+	bool done = false;
+
+	/* Create VM */
+	vm = vm_create_default(VCPU_ID, 0, l1_guest_code);
+	vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
+	vmx = vcpu_alloc_vmx(vm, &vmx_pages_gva);
+	vcpu_args_set(vm, VCPU_ID, 1, vmx_pages_gva);
+	run = vcpu_state(vm, VCPU_ID);
+
+	/* Add an extra memory slot for testing dirty logging */
+	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
+				    GUEST_TEST_MEM,
+				    TEST_MEM_SLOT_INDEX,
+				    TEST_MEM_SIZE,
+				    KVM_MEM_LOG_DIRTY_PAGES);
+
+	/*
+	 * Add an identity map for GVA range [0xc0000000, 0xc0002000).  This
+	 * affects both L1 and L2.  However...
+	 */
+	virt_map(vm, GUEST_TEST_MEM, GUEST_TEST_MEM,
+		 TEST_MEM_SIZE * 4096, 0);
+
+	/*
+	 * ... pages in the L2 GPA range [0xc0001000, 0xc0003000) will map to
+	 * 0xc0000000.
+	 *
+	 * Note that prepare_eptp should be called only L1's GPA map is done,
+	 * meaning after the last call to virt_map.
+	 */
+	prepare_eptp(vmx, vm, 0);
+	nested_map_memslot(vmx, vm, 0, 0);
+	nested_map(vmx, vm, NESTED_TEST_MEM1, GUEST_TEST_MEM, 4096, 0);
+	nested_map(vmx, vm, NESTED_TEST_MEM2, GUEST_TEST_MEM, 4096, 0);
+
+	bmap = bitmap_alloc(TEST_MEM_SIZE);
+	host_test_mem = addr_gpa2hva(vm, GUEST_TEST_MEM);
+
+	while (!done) {
+		memset(host_test_mem, 0xaa, TEST_MEM_SIZE * 4096);
+		_vcpu_run(vm, VCPU_ID);
+		TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
+			    "Unexpected exit reason: %u (%s),\n",
+			    run->exit_reason,
+			    exit_reason_str(run->exit_reason));
+
+		switch (get_ucall(vm, VCPU_ID, &uc)) {
+		case UCALL_ABORT:
+			TEST_ASSERT(false, "%s at %s:%d", (const char *)uc.args[0],
+				    __FILE__, uc.args[1]);
+			/* NOT REACHED */
+		case UCALL_SYNC:
+			/*
+			 * The nested guest wrote at offset 0x1000 in the memslot, but the
+			 * dirty bitmap must be filled in according to L1 GPA, not L2.
+			 */
+			kvm_vm_get_dirty_log(vm, TEST_MEM_SLOT_INDEX, bmap);
+			if (uc.args[1]) {
+				TEST_ASSERT(test_bit(0, bmap), "Page 0 incorrectly reported clean\n");
+				TEST_ASSERT(host_test_mem[0] == 1, "Page 0 not written by guest\n");
+			} else {
+				TEST_ASSERT(!test_bit(0, bmap), "Page 0 incorrectly reported dirty\n");
+				TEST_ASSERT(host_test_mem[0] == 0xaaaaaaaaaaaaaaaaULL, "Page 0 written by guest\n");
+			}
+
+			TEST_ASSERT(!test_bit(1, bmap), "Page 1 incorrectly reported dirty\n");
+			TEST_ASSERT(host_test_mem[4096 / 8] == 0xaaaaaaaaaaaaaaaaULL, "Page 1 written by guest\n");
+			TEST_ASSERT(!test_bit(2, bmap), "Page 2 incorrectly reported dirty\n");
+			TEST_ASSERT(host_test_mem[8192 / 8] == 0xaaaaaaaaaaaaaaaaULL, "Page 2 written by guest\n");
+			break;
+		case UCALL_DONE:
+			done = true;
+			break;
+		default:
+			TEST_ASSERT(false, "Unknown ucall 0x%x.", uc.cmd);
+		}
+	}
+}