Merge tag 'kvm-x86-selftests_utils-6.10' of https://github.com/kvm-x86/linux into HEAD

KVM selftests treewide updates for 6.10:

 - Define _GNU_SOURCE for all selftests to fix a warning that was introduced by
   a change to kselftest_harness.h late in the 6.9 cycle, and because forcing
   every test to #define _GNU_SOURCE is painful.

 - Provide a global psuedo-RNG instance for all tests, so that library code can
   generate random, but determinstic numbers.

 - Use the global pRNG to randomly force emulation of select writes from guest
   code on x86, e.g. to help validate KVM's emulation of locked accesses.

 - Rename kvm_util_base.h back to kvm_util.h, as the weird layer of indirection
   was added purely to avoid manually #including ucall_common.h in a handful of
   locations.

 - Allocate and initialize x86's GDT, IDT, TSS, segments, and default exception
   handlers at VM creation, instead of forcing tests to manually trigger the
   related setup.

Author: bonzini

tools/testing/selftests/kvm/Makefile

@@ -230,8 +230,8 @@ LINUX_TOOL_ARCH_INCLUDE = $(top_srcdir)/tools/arch/$(ARCH)/include
 endif
 CFLAGS += -Wall -Wstrict-prototypes -Wuninitialized -O2 -g -std=gnu99 \
 	-Wno-gnu-variable-sized-type-not-at-end -MD -MP -DCONFIG_64BIT \
-	-fno-builtin-memcmp -fno-builtin-memcpy -fno-builtin-memset \
-	-fno-builtin-strnlen \
+	-D_GNU_SOURCE -fno-builtin-memcmp -fno-builtin-memcpy \
+	-fno-builtin-memset -fno-builtin-strnlen \
 	-fno-stack-protector -fno-PIE -I$(LINUX_TOOL_INCLUDE) \
 	-I$(LINUX_TOOL_ARCH_INCLUDE) -I$(LINUX_HDR_PATH) -Iinclude \
 	-I$(<D) -Iinclude/$(ARCH_DIR) -I ../rseq -I.. $(EXTRA_CFLAGS) \

tools/testing/selftests/kvm/aarch64/arch_timer.c

@@ -5,13 +5,12 @@
  *
  * Copyright (c) 2021, Google LLC.
  */
-#define _GNU_SOURCE
-
 #include "arch_timer.h"
 #include "delay.h"
 #include "gic.h"
 #include "processor.h"
 #include "timer_test.h"
+#include "ucall_common.h"
 #include "vgic.h"
 
 enum guest_stage {

tools/testing/selftests/kvm/aarch64/page_fault_test.c

@@ -7,7 +7,6 @@
  * hugetlbfs with a hole). It checks that the expected handling method is
  * called (e.g., uffd faults with the right address and write/read flag).
  */
-#define _GNU_SOURCE
 #include <linux/bitmap.h>
 #include <fcntl.h>
 #include <test_util.h>

tools/testing/selftests/kvm/aarch64/psci_test.c

@@ -11,8 +11,6 @@
  *    KVM_SYSTEM_EVENT_SUSPEND UAPI.
  */
 
-#define _GNU_SOURCE
-
 #include <linux/kernel.h>
 #include <linux/psci.h>
 #include <asm/cputype.h>

tools/testing/selftests/kvm/aarch64/vgic_init.c

@@ -4,7 +4,6 @@
  *
  * Copyright (C) 2020, Red Hat, Inc.
  */
-#define _GNU_SOURCE
 #include <linux/kernel.h>
 #include <sys/syscall.h>
 #include <asm/kvm.h>

tools/testing/selftests/kvm/arch_timer.c

@@ -19,16 +19,14 @@
  *
  * Copyright (c) 2021, Google LLC.
  */
-
-#define _GNU_SOURCE
-
 #include <stdlib.h>
 #include <pthread.h>
 #include <linux/sizes.h>
 #include <linux/bitmap.h>
 #include <sys/sysinfo.h>
 
 #include "timer_test.h"
+#include "ucall_common.h"
 
 struct test_args test_args = {
 	.nr_vcpus = NR_VCPUS_DEF,

tools/testing/selftests/kvm/demand_paging_test.c

@@ -6,9 +6,6 @@
  * Copyright (C) 2018, Red Hat, Inc.
  * Copyright (C) 2019, Google, Inc.
  */
-
-#define _GNU_SOURCE /* for pipe2 */
-
 #include <inttypes.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -21,6 +18,7 @@
 #include "test_util.h"
 #include "memstress.h"
 #include "guest_modes.h"
+#include "ucall_common.h"
 #include "userfaultfd_util.h"
 
 #ifdef __NR_userfaultfd

tools/testing/selftests/kvm/dirty_log_perf_test.c

@@ -18,6 +18,7 @@
 #include "test_util.h"
 #include "memstress.h"
 #include "guest_modes.h"
+#include "ucall_common.h"
 
 #ifdef __aarch64__
 #include "aarch64/vgic.h"
@@ -129,7 +130,6 @@ struct test_params {
 	enum vm_mem_backing_src_type backing_src;
 	int slots;
 	uint32_t write_percent;
-	uint32_t random_seed;
 	bool random_access;
 };
 
@@ -153,8 +153,6 @@ static void run_test(enum vm_guest_mode mode, void *arg)
 				 p->slots, p->backing_src,
 				 p->partition_vcpu_memory_access);
 
-	pr_info("Random seed: %u\n", p->random_seed);
-	memstress_set_random_seed(vm, p->random_seed);
 	memstress_set_write_percent(vm, p->write_percent);
 
 	guest_num_pages = (nr_vcpus * guest_percpu_mem_size) >> vm->page_shift;
@@ -343,11 +341,13 @@ int main(int argc, char *argv[])
 		.partition_vcpu_memory_access = true,
 		.backing_src = DEFAULT_VM_MEM_SRC,
 		.slots = 1,
-		.random_seed = 1,
 		.write_percent = 100,
 	};
 	int opt;
 
+	/* Override the seed to be deterministic by default. */
+	guest_random_seed = 1;
+
 	dirty_log_manual_caps =
 		kvm_check_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2);
 	dirty_log_manual_caps &= (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE |
@@ -392,7 +392,7 @@ int main(int argc, char *argv[])
 			p.phys_offset = strtoull(optarg, NULL, 0);
 			break;
 		case 'r':
-			p.random_seed = atoi_positive("Random seed", optarg);
+			guest_random_seed = atoi_positive("Random seed", optarg);
 			break;
 		case 's':
 			p.backing_src = parse_backing_src_type(optarg);

tools/testing/selftests/kvm/dirty_log_test.c

@@ -4,9 +4,6 @@
  *
  * Copyright (C) 2018, Red Hat, Inc.
  */
-
-#define _GNU_SOURCE /* for program_invocation_name */
-
 #include <stdio.h>
 #include <stdlib.h>
 #include <pthread.h>
@@ -23,6 +20,7 @@
 #include "test_util.h"
 #include "guest_modes.h"
 #include "processor.h"
+#include "ucall_common.h"
 
 #define DIRTY_MEM_BITS 30 /* 1G */
 #define PAGE_SHIFT_4K  12
@@ -76,7 +74,6 @@
 static uint64_t host_page_size;
 static uint64_t guest_page_size;
 static uint64_t guest_num_pages;
-static uint64_t random_array[TEST_PAGES_PER_LOOP];
 static uint64_t iteration;
 
 /*
@@ -109,19 +106,19 @@ static void guest_code(void)
 	 */
 	for (i = 0; i < guest_num_pages; i++) {
 		addr = guest_test_virt_mem + i * guest_page_size;
-		*(uint64_t *)addr = READ_ONCE(iteration);
+		vcpu_arch_put_guest(*(uint64_t *)addr, READ_ONCE(iteration));
 	}
 
 	while (true) {
 		for (i = 0; i < TEST_PAGES_PER_LOOP; i++) {
 			addr = guest_test_virt_mem;
-			addr += (READ_ONCE(random_array[i]) % guest_num_pages)
+			addr += (guest_random_u64(&guest_rng) % guest_num_pages)
 				* guest_page_size;
 			addr = align_down(addr, host_page_size);
-			*(uint64_t *)addr = READ_ONCE(iteration);
+
+			vcpu_arch_put_guest(*(uint64_t *)addr, READ_ONCE(iteration));
 		}
 
-		/* Tell the host that we need more random numbers */
 		GUEST_SYNC(1);
 	}
 }
@@ -508,20 +505,10 @@ static void log_mode_after_vcpu_run(struct kvm_vcpu *vcpu, int ret, int err)
 		mode->after_vcpu_run(vcpu, ret, err);
 }
 
-static void generate_random_array(uint64_t *guest_array, uint64_t size)
-{
-	uint64_t i;
-
-	for (i = 0; i < size; i++)
-		guest_array[i] = random();
-}
-
 static void *vcpu_worker(void *data)
 {
 	int ret;
 	struct kvm_vcpu *vcpu = data;
-	struct kvm_vm *vm = vcpu->vm;
-	uint64_t *guest_array;
 	uint64_t pages_count = 0;
 	struct kvm_signal_mask *sigmask = alloca(offsetof(struct kvm_signal_mask, sigset)
 						 + sizeof(sigset_t));
@@ -540,11 +527,8 @@ static void *vcpu_worker(void *data)
 	sigemptyset(sigset);
 	sigaddset(sigset, SIG_IPI);
 
-	guest_array = addr_gva2hva(vm, (vm_vaddr_t)random_array);
-
 	while (!READ_ONCE(host_quit)) {
 		/* Clear any existing kick signals */
-		generate_random_array(guest_array, TEST_PAGES_PER_LOOP);
 		pages_count += TEST_PAGES_PER_LOOP;
 		/* Let the guest dirty the random pages */
 		ret = __vcpu_run(vcpu);

tools/testing/selftests/kvm/guest_memfd_test.c

@@ -4,8 +4,6 @@
  *
  * Author: Chao Peng <[email protected]>
  */
-
-#define _GNU_SOURCE
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
@@ -19,8 +17,8 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 
+#include "kvm_util.h"
 #include "test_util.h"
-#include "kvm_util_base.h"
 
 static void test_file_read_write(int fd)
 {