[PATCH v4 2/3] KVM: selftests: Enable pre_fault_memory_test for arm64

[Jack Thomson <jackabt.amazon@gmail.com>]

From: Jack Thomson <jackabt@amazon.com>

Enable the pre_fault_memory_test to run on arm64 by making it work with
different guest page sizes and testing multiple guest configurations.

Update the test_assert to compare against the UCALL_EXIT_REASON, for
portability, as arm64 exits with KVM_EXIT_MMIO while x86 uses
KVM_EXIT_IO.

Signed-off-by: Jack Thomson <jackabt@amazon.com>
---
 tools/testing/selftests/kvm/Makefile.kvm      |  1 +
 .../selftests/kvm/pre_fault_memory_test.c     | 85 ++++++++++++++-----
 2 files changed, 63 insertions(+), 23 deletions(-)

diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
index ba5c2b643efa..6d6a74ddad30 100644
--- a/tools/testing/selftests/kvm/Makefile.kvm
+++ b/tools/testing/selftests/kvm/Makefile.kvm
@@ -187,6 +187,7 @@ TEST_GEN_PROGS_arm64 += memslot_perf_test
 TEST_GEN_PROGS_arm64 += mmu_stress_test
 TEST_GEN_PROGS_arm64 += rseq_test
 TEST_GEN_PROGS_arm64 += steal_time
+TEST_GEN_PROGS_arm64 += pre_fault_memory_test
 
 TEST_GEN_PROGS_s390 = $(TEST_GEN_PROGS_COMMON)
 TEST_GEN_PROGS_s390 += s390/memop
diff --git a/tools/testing/selftests/kvm/pre_fault_memory_test.c b/tools/testing/selftests/kvm/pre_fault_memory_test.c
index 93e603d91311..be1a84a6c137 100644
--- a/tools/testing/selftests/kvm/pre_fault_memory_test.c
+++ b/tools/testing/selftests/kvm/pre_fault_memory_test.c
@@ -11,19 +11,29 @@
 #include <kvm_util.h>
 #include <processor.h>
 #include <pthread.h>
+#include <guest_modes.h>
 
 /* Arbitrarily chosen values */
-#define TEST_SIZE		(SZ_2M + PAGE_SIZE)
-#define TEST_NPAGES		(TEST_SIZE / PAGE_SIZE)
+#define TEST_BASE_SIZE		SZ_2M
 #define TEST_SLOT		10
 
-static void guest_code(uint64_t base_gva)
+/* Storage of test info to share with guest code */
+struct test_config {
+	uint64_t page_size;
+	uint64_t test_size;
+	uint64_t test_num_pages;
+};
+
+static struct test_config test_config;
+
+static void guest_code(uint64_t base_gpa)
 {
 	volatile uint64_t val __used;
+	struct test_config *config = &test_config;
 	int i;
 
-	for (i = 0; i < TEST_NPAGES; i++) {
-		uint64_t *src = (uint64_t *)(base_gva + i * PAGE_SIZE);
+	for (i = 0; i < config->test_num_pages; i++) {
+		uint64_t *src = (uint64_t *)(base_gpa + i * config->page_size);
 
 		val = *src;
 	}
@@ -56,7 +66,7 @@ static void *delete_slot_worker(void *__data)
 		cpu_relax();
 
 	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, data->gpa,
-				    TEST_SLOT, TEST_NPAGES, data->flags);
+				    TEST_SLOT, test_config.test_num_pages, data->flags);
 
 	return NULL;
 }
@@ -159,22 +169,35 @@ static void pre_fault_memory(struct kvm_vcpu *vcpu, u64 base_gpa, u64 offset,
 					  KVM_PRE_FAULT_MEMORY, ret, vcpu->vm);
 }
 
-static void __test_pre_fault_memory(unsigned long vm_type, bool private)
+struct test_params {
+	unsigned long vm_type;
+	bool private;
+};
+
+static void __test_pre_fault_memory(enum vm_guest_mode guest_mode, void *arg)
 {
 	uint64_t gpa, gva, alignment, guest_page_size;
+	struct test_params *p = arg;
 	const struct vm_shape shape = {
-		.mode = VM_MODE_DEFAULT,
-		.type = vm_type,
+		.mode = guest_mode,
+		.type = p->vm_type,
 	};
 	struct kvm_vcpu *vcpu;
 	struct kvm_run *run;
 	struct kvm_vm *vm;
 	struct ucall uc;
 
+	pr_info("Testing guest mode: %s\n", vm_guest_mode_string(guest_mode));
+
 	vm = vm_create_shape_with_one_vcpu(shape, &vcpu, guest_code);
 
-	alignment = guest_page_size = vm_guest_mode_params[VM_MODE_DEFAULT].page_size;
-	gpa = (vm->max_gfn - TEST_NPAGES) * guest_page_size;
+	guest_page_size = vm_guest_mode_params[guest_mode].page_size;
+
+	test_config.page_size = guest_page_size;
+	test_config.test_size = TEST_BASE_SIZE + test_config.page_size;
+	test_config.test_num_pages = vm_calc_num_guest_pages(vm->mode, test_config.test_size);
+
+	gpa = (vm->max_gfn - test_config.test_num_pages) * test_config.page_size;
 #ifdef __s390x__
 	alignment = max(0x100000UL, guest_page_size);
 #else
@@ -183,23 +206,32 @@ static void __test_pre_fault_memory(unsigned long vm_type, bool private)
 	gpa = align_down(gpa, alignment);
 	gva = gpa & ((1ULL << (vm->va_bits - 1)) - 1);
 
-	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, gpa, TEST_SLOT,
-				    TEST_NPAGES, private ? KVM_MEM_GUEST_MEMFD : 0);
-	virt_map(vm, gva, gpa, TEST_NPAGES);
+	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
+				    gpa, TEST_SLOT, test_config.test_num_pages,
+				    p->private ? KVM_MEM_GUEST_MEMFD : 0);
+	virt_map(vm, gva, gpa, test_config.test_num_pages);
+
+	if (p->private)
+		vm_mem_set_private(vm, gpa, test_config.test_size);
+	pre_fault_memory(vcpu, gpa, 0, TEST_BASE_SIZE, 0, p->private);
+	/* Test pre-faulting over an already faulted range */
+	pre_fault_memory(vcpu, gpa, 0, TEST_BASE_SIZE, 0, p->private);
+	pre_fault_memory(vcpu, gpa, TEST_BASE_SIZE,
+			 test_config.page_size * 2, test_config.page_size, p->private);
+	pre_fault_memory(vcpu, gpa, test_config.test_size,
+			 test_config.page_size, test_config.page_size, p->private);
 
-	if (private)
-		vm_mem_set_private(vm, gpa, TEST_SIZE);
+	vcpu_args_set(vcpu, 1, gva);
 
-	pre_fault_memory(vcpu, gpa, 0, SZ_2M, 0, private);
-	pre_fault_memory(vcpu, gpa, SZ_2M, PAGE_SIZE * 2, PAGE_SIZE, private);
-	pre_fault_memory(vcpu, gpa, TEST_SIZE, PAGE_SIZE, PAGE_SIZE, private);
+	/* Export the shared variables to the guest. */
+	sync_global_to_guest(vm, test_config);
 
-	vcpu_args_set(vcpu, 1, gva);
 	vcpu_run(vcpu);
 
 	run = vcpu->run;
-	TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
-		    "Wanted KVM_EXIT_IO, got exit reason: %u (%s)",
+	TEST_ASSERT(run->exit_reason == UCALL_EXIT_REASON,
+		    "Wanted %s, got exit reason: %u (%s)",
+		    exit_reason_str(UCALL_EXIT_REASON),
 		    run->exit_reason, exit_reason_str(run->exit_reason));
 
 	switch (get_ucall(vcpu, &uc)) {
@@ -218,18 +250,25 @@ static void __test_pre_fault_memory(unsigned long vm_type, bool private)
 
 static void test_pre_fault_memory(unsigned long vm_type, bool private)
 {
+	struct test_params p = {
+		.vm_type = vm_type,
+		.private = private,
+	};
+
 	if (vm_type && !(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(vm_type))) {
 		pr_info("Skipping tests for vm_type 0x%lx\n", vm_type);
 		return;
 	}
 
-	__test_pre_fault_memory(vm_type, private);
+	for_each_guest_mode(__test_pre_fault_memory, &p);
 }
 
 int main(int argc, char *argv[])
 {
 	TEST_REQUIRE(kvm_check_cap(KVM_CAP_PRE_FAULT_MEMORY));
 
+	guest_modes_append_default();
+
 	test_pre_fault_memory(0, false);
 #ifdef __x86_64__
 	test_pre_fault_memory(KVM_X86_SW_PROTECTED_VM, false);
-- 
2.43.0