1 files changed, 424 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/set_memory_region_test.c b/tools/testing/selftests/kvm/set_memory_region_test.c
new file mode 100644
index 000000000000..0d55f508d595
--- /dev/null
+++ b/tools/testing/selftests/kvm/set_memory_region_test.c
@@ -0,0 +1,424 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE /* for program_invocation_short_name */
+#include <fcntl.h>
+#include <pthread.h>
+#include <sched.h>
+#include <semaphore.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+
+#include <linux/compiler.h>
+
+#include <test_util.h>
+#include <kvm_util.h>
+#include <processor.h>
+
+/*
+ * s390x needs at least 1MB alignment, and the x86_64 MOVE/DELETE tests need a
+ * 2MB sized and aligned region so that the initial region corresponds to
+ * exactly one large page.
+ */
+#define MEM_REGION_SIZE		0x200000
+
+#ifdef __x86_64__
+/*
+ * Somewhat arbitrary location and slot, intended to not overlap anything.
+ */
+#define MEM_REGION_GPA		0xc0000000
+#define MEM_REGION_SLOT		10
+
+static const uint64_t MMIO_VAL = 0xbeefull;
+
+extern const uint64_t final_rip_start;
+extern const uint64_t final_rip_end;
+
+static sem_t vcpu_ready;
+
+static inline uint64_t guest_spin_on_val(uint64_t spin_val)
+{
+	uint64_t val;
+
+	do {
+		val = READ_ONCE(*((uint64_t *)MEM_REGION_GPA));
+	} while (val == spin_val);
+
+	GUEST_SYNC(0);
+	return val;
+}
+
+static void *vcpu_worker(void *data)
+{
+	struct kvm_vcpu *vcpu = data;
+	struct kvm_run *run = vcpu->run;
+	struct ucall uc;
+	uint64_t cmd;
+
+	/*
+	 * Loop until the guest is done.  Re-enter the guest on all MMIO exits,
+	 * which will occur if the guest attempts to access a memslot after it
+	 * has been deleted or while it is being moved .
+	 */
+	while (1) {
+		vcpu_run(vcpu);
+
+		if (run->exit_reason == KVM_EXIT_IO) {
+			cmd = get_ucall(vcpu, &uc);
+			if (cmd != UCALL_SYNC)
+				break;
+
+			sem_post(&vcpu_ready);
+			continue;
+		}
+
+		if (run->exit_reason != KVM_EXIT_MMIO)
+			break;
+
+		TEST_ASSERT(!run->mmio.is_write, "Unexpected exit mmio write");
+		TEST_ASSERT(run->mmio.len == 8,
+			    "Unexpected exit mmio size = %u", run->mmio.len);
+
+		TEST_ASSERT(run->mmio.phys_addr == MEM_REGION_GPA,
+			    "Unexpected exit mmio address = 0x%llx",
+			    run->mmio.phys_addr);
+		memcpy(run->mmio.data, &MMIO_VAL, 8);
+	}
+
+	if (run->exit_reason == KVM_EXIT_IO && cmd == UCALL_ABORT)
+		REPORT_GUEST_ASSERT_1(uc, "val = %lu");
+
+	return NULL;
+}
+
+static void wait_for_vcpu(void)
+{
+	struct timespec ts;
+
+	TEST_ASSERT(!clock_gettime(CLOCK_REALTIME, &ts),
+		    "clock_gettime() failed: %d\n", errno);
+
+	ts.tv_sec += 2;
+	TEST_ASSERT(!sem_timedwait(&vcpu_ready, &ts),
+		    "sem_timedwait() failed: %d\n", errno);
+
+	/* Wait for the vCPU thread to reenter the guest. */
+	usleep(100000);
+}
+
+static struct kvm_vm *spawn_vm(struct kvm_vcpu **vcpu, pthread_t *vcpu_thread,
+			       void *guest_code)
+{
+	struct kvm_vm *vm;
+	uint64_t *hva;
+	uint64_t gpa;
+
+	vm = vm_create_with_one_vcpu(vcpu, guest_code);
+
+	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS_THP,
+				    MEM_REGION_GPA, MEM_REGION_SLOT,
+				    MEM_REGION_SIZE / getpagesize(), 0);
+
+	/*
+	 * Allocate and map two pages so that the GPA accessed by guest_code()
+	 * stays valid across the memslot move.
+	 */
+	gpa = vm_phy_pages_alloc(vm, 2, MEM_REGION_GPA, MEM_REGION_SLOT);
+	TEST_ASSERT(gpa == MEM_REGION_GPA, "Failed vm_phy_pages_alloc\n");
+
+	virt_map(vm, MEM_REGION_GPA, MEM_REGION_GPA, 2);
+
+	/* Ditto for the host mapping so that both pages can be zeroed. */
+	hva = addr_gpa2hva(vm, MEM_REGION_GPA);
+	memset(hva, 0, 2 * 4096);
+
+	pthread_create(vcpu_thread, NULL, vcpu_worker, *vcpu);
+
+	/* Ensure the guest thread is spun up. */
+	wait_for_vcpu();
+
+	return vm;
+}
+
+
+static void guest_code_move_memory_region(void)
+{
+	uint64_t val;
+
+	GUEST_SYNC(0);
+
+	/*
+	 * Spin until the memory region starts getting moved to a
+	 * misaligned address.
+	 * Every region move may or may not trigger MMIO, as the
+	 * window where the memslot is invalid is usually quite small.
+	 */
+	val = guest_spin_on_val(0);
+	GUEST_ASSERT_1(val == 1 || val == MMIO_VAL, val);
+
+	/* Spin until the misaligning memory region move completes. */
+	val = guest_spin_on_val(MMIO_VAL);
+	GUEST_ASSERT_1(val == 1 || val == 0, val);
+
+	/* Spin until the memory region starts to get re-aligned. */
+	val = guest_spin_on_val(0);
+	GUEST_ASSERT_1(val == 1 || val == MMIO_VAL, val);
+
+	/* Spin until the re-aligning memory region move completes. */
+	val = guest_spin_on_val(MMIO_VAL);
+	GUEST_ASSERT_1(val == 1, val);
+
+	GUEST_DONE();
+}
+
+static void test_move_memory_region(void)
+{
+	pthread_t vcpu_thread;
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+	uint64_t *hva;
+
+	vm = spawn_vm(&vcpu, &vcpu_thread, guest_code_move_memory_region);
+
+	hva = addr_gpa2hva(vm, MEM_REGION_GPA);
+
+	/*
+	 * Shift the region's base GPA.  The guest should not see "2" as the
+	 * hva->gpa translation is misaligned, i.e. the guest is accessing a
+	 * different host pfn.
+	 */
+	vm_mem_region_move(vm, MEM_REGION_SLOT, MEM_REGION_GPA - 4096);
+	WRITE_ONCE(*hva, 2);
+
+	/*
+	 * The guest _might_ see an invalid memslot and trigger MMIO, but it's
+	 * a tiny window.  Spin and defer the sync until the memslot is
+	 * restored and guest behavior is once again deterministic.
+	 */
+	usleep(100000);
+
+	/*
+	 * Note, value in memory needs to be changed *before* restoring the
+	 * memslot, else the guest could race the update and see "2".
+	 */
+	WRITE_ONCE(*hva, 1);
+
+	/* Restore the original base, the guest should see "1". */
+	vm_mem_region_move(vm, MEM_REGION_SLOT, MEM_REGION_GPA);
+	wait_for_vcpu();
+	/* Defered sync from when the memslot was misaligned (above). */
+	wait_for_vcpu();
+
+	pthread_join(vcpu_thread, NULL);
+
+	kvm_vm_free(vm);
+}
+
+static void guest_code_delete_memory_region(void)
+{
+	uint64_t val;
+
+	GUEST_SYNC(0);
+
+	/* Spin until the memory region is deleted. */
+	val = guest_spin_on_val(0);
+	GUEST_ASSERT_1(val == MMIO_VAL, val);
+
+	/* Spin until the memory region is recreated. */
+	val = guest_spin_on_val(MMIO_VAL);
+	GUEST_ASSERT_1(val == 0, val);
+
+	/* Spin until the memory region is deleted. */
+	val = guest_spin_on_val(0);
+	GUEST_ASSERT_1(val == MMIO_VAL, val);
+
+	asm("1:\n\t"
+	    ".pushsection .rodata\n\t"
+	    ".global final_rip_start\n\t"
+	    "final_rip_start: .quad 1b\n\t"
+	    ".popsection");
+
+	/* Spin indefinitely (until the code memslot is deleted). */
+	guest_spin_on_val(MMIO_VAL);
+
+	asm("1:\n\t"
+	    ".pushsection .rodata\n\t"
+	    ".global final_rip_end\n\t"
+	    "final_rip_end: .quad 1b\n\t"
+	    ".popsection");
+
+	GUEST_ASSERT_1(0, 0);
+}
+
+static void test_delete_memory_region(void)
+{
+	pthread_t vcpu_thread;
+	struct kvm_vcpu *vcpu;
+	struct kvm_regs regs;
+	struct kvm_run *run;
+	struct kvm_vm *vm;
+
+	vm = spawn_vm(&vcpu, &vcpu_thread, guest_code_delete_memory_region);
+
+	/* Delete the memory region, the guest should not die. */
+	vm_mem_region_delete(vm, MEM_REGION_SLOT);
+	wait_for_vcpu();
+
+	/* Recreate the memory region.  The guest should see "0". */
+	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS_THP,
+				    MEM_REGION_GPA, MEM_REGION_SLOT,
+				    MEM_REGION_SIZE / getpagesize(), 0);
+	wait_for_vcpu();
+
+	/* Delete the region again so that there's only one memslot left. */
+	vm_mem_region_delete(vm, MEM_REGION_SLOT);
+	wait_for_vcpu();
+
+	/*
+	 * Delete the primary memslot.  This should cause an emulation error or
+	 * shutdown due to the page tables getting nuked.
+	 */
+	vm_mem_region_delete(vm, 0);
+
+	pthread_join(vcpu_thread, NULL);
+
+	run = vcpu->run;
+
+	TEST_ASSERT(run->exit_reason == KVM_EXIT_SHUTDOWN ||
+		    run->exit_reason == KVM_EXIT_INTERNAL_ERROR,
+		    "Unexpected exit reason = %d", run->exit_reason);
+
+	vcpu_regs_get(vcpu, &regs);
+
+	/*
+	 * On AMD, after KVM_EXIT_SHUTDOWN the VMCB has been reinitialized already,
+	 * so the instruction pointer would point to the reset vector.
+	 */
+	if (run->exit_reason == KVM_EXIT_INTERNAL_ERROR)
+		TEST_ASSERT(regs.rip >= final_rip_start &&
+			    regs.rip < final_rip_end,
+			    "Bad rip, expected 0x%lx - 0x%lx, got 0x%llx\n",
+			    final_rip_start, final_rip_end, regs.rip);
+
+	kvm_vm_free(vm);
+}
+
+static void test_zero_memory_regions(void)
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_run *run;
+	struct kvm_vm *vm;
+
+	pr_info("Testing KVM_RUN with zero added memory regions\n");
+
+	vm = vm_create_barebones();
+	vcpu = __vm_vcpu_add(vm, 0);
+
+	vm_ioctl(vm, KVM_SET_NR_MMU_PAGES, (void *)64ul);
+	vcpu_run(vcpu);
+
+	run = vcpu->run;
+	TEST_ASSERT(run->exit_reason == KVM_EXIT_INTERNAL_ERROR,
+		    "Unexpected exit_reason = %u\n", run->exit_reason);
+
+	kvm_vm_free(vm);
+}
+#endif /* __x86_64__ */
+
+/*
+ * Test it can be added memory slots up to KVM_CAP_NR_MEMSLOTS, then any
+ * tentative to add further slots should fail.
+ */
+static void test_add_max_memory_regions(void)
+{
+	int ret;
+	struct kvm_vm *vm;
+	uint32_t max_mem_slots;
+	uint32_t slot;
+	void *mem, *mem_aligned, *mem_extra;
+	size_t alignment;
+
+#ifdef __s390x__
+	/* On s390x, the host address must be aligned to 1M (due to PGSTEs) */
+	alignment = 0x100000;
+#else
+	alignment = 1;
+#endif
+
+	max_mem_slots = kvm_check_cap(KVM_CAP_NR_MEMSLOTS);
+	TEST_ASSERT(max_mem_slots > 0,
+		    "KVM_CAP_NR_MEMSLOTS should be greater than 0");
+	pr_info("Allowed number of memory slots: %i\n", max_mem_slots);
+
+	vm = vm_create_barebones();
+
+	/* Check it can be added memory slots up to the maximum allowed */
+	pr_info("Adding slots 0..%i, each memory region with %dK size\n",
+		(max_mem_slots - 1), MEM_REGION_SIZE >> 10);
+
+	mem = mmap(NULL, (size_t)max_mem_slots * MEM_REGION_SIZE + alignment,
+		   PROT_READ | PROT_WRITE,
+		   MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0);
+	TEST_ASSERT(mem != MAP_FAILED, "Failed to mmap() host");
+	mem_aligned = (void *)(((size_t) mem + alignment - 1) & ~(alignment - 1));
+
+	for (slot = 0; slot < max_mem_slots; slot++)
+		vm_set_user_memory_region(vm, slot, 0,
+					  ((uint64_t)slot * MEM_REGION_SIZE),
+					  MEM_REGION_SIZE,
+					  mem_aligned + (uint64_t)slot * MEM_REGION_SIZE);
+
+	/* Check it cannot be added memory slots beyond the limit */
+	mem_extra = mmap(NULL, MEM_REGION_SIZE, PROT_READ | PROT_WRITE,
+			 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+	TEST_ASSERT(mem_extra != MAP_FAILED, "Failed to mmap() host");
+
+	ret = __vm_set_user_memory_region(vm, max_mem_slots, 0,
+					  (uint64_t)max_mem_slots * MEM_REGION_SIZE,
+					  MEM_REGION_SIZE, mem_extra);
+	TEST_ASSERT(ret == -1 && errno == EINVAL,
+		    "Adding one more memory slot should fail with EINVAL");
+
+	munmap(mem, (size_t)max_mem_slots * MEM_REGION_SIZE + alignment);
+	munmap(mem_extra, MEM_REGION_SIZE);
+	kvm_vm_free(vm);
+}
+
+int main(int argc, char *argv[])
+{
+#ifdef __x86_64__
+	int i, loops;
+#endif
+
+	/* Tell stdout not to buffer its content */
+	setbuf(stdout, NULL);
+
+#ifdef __x86_64__
+	/*
+	 * FIXME: the zero-memslot test fails on aarch64 and s390x because
+	 * KVM_RUN fails with ENOEXEC or EFAULT.
+	 */
+	test_zero_memory_regions();
+#endif
+
+	test_add_max_memory_regions();
+
+#ifdef __x86_64__
+	if (argc > 1)
+		loops = atoi(argv[1]);
+	else
+		loops = 10;
+
+	pr_info("Testing MOVE of in-use region, %d loops\n", loops);
+	for (i = 0; i < loops; i++)
+		test_move_memory_region();
+
+	pr_info("Testing DELETE of in-use region, %d loops\n", loops);
+	for (i = 0; i < loops; i++)
+		test_delete_memory_region();
+#endif
+
+	return 0;
+}