Merge tag 'kvmarm-6.2' of https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 updates for 6.2

- Enable the per-vcpu dirty-ring tracking mechanism, together with an
  option to keep the good old dirty log around for pages that are
  dirtied by something other than a vcpu.

- Switch to the relaxed parallel fault handling, using RCU to delay
  page table reclaim and giving better performance under load.

- Relax the MTE ABI, allowing a VMM to use the MAP_SHARED mapping
  option, which multi-process VMMs such as crosvm rely on.

- Merge the pKVM shadow vcpu state tracking that allows the hypervisor
  to have its own view of a vcpu, keeping that state private.

- Add support for the PMUv3p5 architecture revision, bringing support
  for 64bit counters on systems that support it, and fix the
  no-quite-compliant CHAIN-ed counter support for the machines that
  actually exist out there.

- Fix a handful of minor issues around 52bit VA/PA support (64kB pages
  only) as a prefix of the oncoming support for 4kB and 16kB pages.

- Add/Enable/Fix a bunch of selftests covering memslots, breakpoints,
  stage-2 faults and access tracking. You name it, we got it, we
  probably broke it.

- Pick a small set of documentation and spelling fixes, because no
  good merge window would be complete without those.

As a side effect, this tag also drags:

- The 'kvmarm-fixes-6.1-3' tag as a dependency to the dirty-ring
  series

- A shared branch with the arm64 tree that repaints all the system
  registers to match the ARM ARM's naming, and resulting in
  interesting conflicts

1 files changed, 30 insertions, 198 deletions

diff --git a/tools/testing/selftests/kvm/demand_paging_test.c b/tools/testing/selftests/kvm/demand_paging_test.c
index 3a977ddf07b2..b0e1fc4de9e2 100644
--- a/tools/testing/selftests/kvm/demand_paging_test.c
+++ b/tools/testing/selftests/kvm/demand_paging_test.c
@@ -22,23 +22,13 @@
 #include "test_util.h"
 #include "memstress.h"
 #include "guest_modes.h"
+#include "userfaultfd_util.h"
 
 #ifdef __NR_userfaultfd
 
-#ifdef PRINT_PER_PAGE_UPDATES
-#define PER_PAGE_DEBUG(...) printf(__VA_ARGS__)
-#else
-#define PER_PAGE_DEBUG(...) _no_printf(__VA_ARGS__)
-#endif
-
-#ifdef PRINT_PER_VCPU_UPDATES
-#define PER_VCPU_DEBUG(...) printf(__VA_ARGS__)
-#else
-#define PER_VCPU_DEBUG(...) _no_printf(__VA_ARGS__)
-#endif
-
 static int nr_vcpus = 1;
 static uint64_t guest_percpu_mem_size = DEFAULT_PER_VCPU_MEM_SIZE;
+
 static size_t demand_paging_size;
 static char *guest_data_prototype;
 
@@ -67,9 +57,11 @@ static void vcpu_worker(struct memstress_vcpu_args *vcpu_args)
 		       ts_diff.tv_sec, ts_diff.tv_nsec);
 }
 
-static int handle_uffd_page_request(int uffd_mode, int uffd, uint64_t addr)
+static int handle_uffd_page_request(int uffd_mode, int uffd,
+		struct uffd_msg *msg)
 {
 	pid_t tid = syscall(__NR_gettid);
+	uint64_t addr = msg->arg.pagefault.address;
 	struct timespec start;
 	struct timespec ts_diff;
 	int r;
@@ -116,174 +108,32 @@ static int handle_uffd_page_request(int uffd_mode, int uffd, uint64_t addr)
 	return 0;
 }
 
-bool quit_uffd_thread;
-
-struct uffd_handler_args {
+struct test_params {
 	int uffd_mode;
-	int uffd;
-	int pipefd;
-	useconds_t delay;
+	useconds_t uffd_delay;
+	enum vm_mem_backing_src_type src_type;
+	bool partition_vcpu_memory_access;
 };
 
-static void *uffd_handler_thread_fn(void *arg)
-{
-	struct uffd_handler_args *uffd_args = (struct uffd_handler_args *)arg;
-	int uffd = uffd_args->uffd;
-	int pipefd = uffd_args->pipefd;
-	useconds_t delay = uffd_args->delay;
-	int64_t pages = 0;
-	struct timespec start;
-	struct timespec ts_diff;
-
-	clock_gettime(CLOCK_MONOTONIC, &start);
-	while (!quit_uffd_thread) {
-		struct uffd_msg msg;
-		struct pollfd pollfd[2];
-		char tmp_chr;
-		int r;
-		uint64_t addr;
-
-		pollfd[0].fd = uffd;
-		pollfd[0].events = POLLIN;
-		pollfd[1].fd = pipefd;
-		pollfd[1].events = POLLIN;
-
-		r = poll(pollfd, 2, -1);
-		switch (r) {
-		case -1:
-			pr_info("poll err");
-			continue;
-		case 0:
-			continue;
-		case 1:
-			break;
-		default:
-			pr_info("Polling uffd returned %d", r);
-			return NULL;
-		}
-
-		if (pollfd[0].revents & POLLERR) {
-			pr_info("uffd revents has POLLERR");
-			return NULL;
-		}
-
-		if (pollfd[1].revents & POLLIN) {
-			r = read(pollfd[1].fd, &tmp_chr, 1);
-			TEST_ASSERT(r == 1,
-				    "Error reading pipefd in UFFD thread\n");
-			return NULL;
-		}
-
-		if (!(pollfd[0].revents & POLLIN))
-			continue;
-
-		r = read(uffd, &msg, sizeof(msg));
-		if (r == -1) {
-			if (errno == EAGAIN)
-				continue;
-			pr_info("Read of uffd got errno %d\n", errno);
-			return NULL;
-		}
-
-		if (r != sizeof(msg)) {
-			pr_info("Read on uffd returned unexpected size: %d bytes", r);
-			return NULL;
-		}
-
-		if (!(msg.event & UFFD_EVENT_PAGEFAULT))
-			continue;
-
-		if (delay)
-			usleep(delay);
-		addr =  msg.arg.pagefault.address;
-		r = handle_uffd_page_request(uffd_args->uffd_mode, uffd, addr);
-		if (r < 0)
-			return NULL;
-		pages++;
-	}
-
-	ts_diff = timespec_elapsed(start);
-	PER_VCPU_DEBUG("userfaulted %ld pages over %ld.%.9lds. (%f/sec)\n",
-		       pages, ts_diff.tv_sec, ts_diff.tv_nsec,
-		       pages / ((double)ts_diff.tv_sec + (double)ts_diff.tv_nsec / 100000000.0));
-
-	return NULL;
-}
-
-static void setup_demand_paging(struct kvm_vm *vm,
-				pthread_t *uffd_handler_thread, int pipefd,
-				int uffd_mode, useconds_t uffd_delay,
-				struct uffd_handler_args *uffd_args,
-				void *hva, void *alias, uint64_t len)
+static void prefault_mem(void *alias, uint64_t len)
 {
-	bool is_minor = (uffd_mode == UFFDIO_REGISTER_MODE_MINOR);
-	int uffd;
-	struct uffdio_api uffdio_api;
-	struct uffdio_register uffdio_register;
-	uint64_t expected_ioctls = ((uint64_t) 1) << _UFFDIO_COPY;
-	int ret;
+	size_t p;
 
-	PER_PAGE_DEBUG("Userfaultfd %s mode, faults resolved with %s\n",
-		       is_minor ? "MINOR" : "MISSING",
-		       is_minor ? "UFFDIO_CONINUE" : "UFFDIO_COPY");
-
-	/* In order to get minor faults, prefault via the alias. */
-	if (is_minor) {
-		size_t p;
-
-		expected_ioctls = ((uint64_t) 1) << _UFFDIO_CONTINUE;
-
-		TEST_ASSERT(alias != NULL, "Alias required for minor faults");
-		for (p = 0; p < (len / demand_paging_size); ++p) {
-			memcpy(alias + (p * demand_paging_size),
-			       guest_data_prototype, demand_paging_size);
-		}
+	TEST_ASSERT(alias != NULL, "Alias required for minor faults");
+	for (p = 0; p < (len / demand_paging_size); ++p) {
+		memcpy(alias + (p * demand_paging_size),
+		       guest_data_prototype, demand_paging_size);
 	}
-
-	uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
-	TEST_ASSERT(uffd >= 0, __KVM_SYSCALL_ERROR("userfaultfd()", uffd));
-
-	uffdio_api.api = UFFD_API;
-	uffdio_api.features = 0;
-	ret = ioctl(uffd, UFFDIO_API, &uffdio_api);
-	TEST_ASSERT(ret != -1, __KVM_SYSCALL_ERROR("UFFDIO_API", ret));
-
-	uffdio_register.range.start = (uint64_t)hva;
-	uffdio_register.range.len = len;
-	uffdio_register.mode = uffd_mode;
-	ret = ioctl(uffd, UFFDIO_REGISTER, &uffdio_register);
-	TEST_ASSERT(ret != -1, __KVM_SYSCALL_ERROR("UFFDIO_REGISTER", ret));
-	TEST_ASSERT((uffdio_register.ioctls & expected_ioctls) ==
-		    expected_ioctls, "missing userfaultfd ioctls");
-
-	uffd_args->uffd_mode = uffd_mode;
-	uffd_args->uffd = uffd;
-	uffd_args->pipefd = pipefd;
-	uffd_args->delay = uffd_delay;
-	pthread_create(uffd_handler_thread, NULL, uffd_handler_thread_fn,
-		       uffd_args);
-
-	PER_VCPU_DEBUG("Created uffd thread for HVA range [%p, %p)\n",
-		       hva, hva + len);
 }
 
-struct test_params {
-	int uffd_mode;
-	useconds_t uffd_delay;
-	enum vm_mem_backing_src_type src_type;
-	bool partition_vcpu_memory_access;
-};
-
 static void run_test(enum vm_guest_mode mode, void *arg)
 {
 	struct test_params *p = arg;
-	pthread_t *uffd_handler_threads = NULL;
-	struct uffd_handler_args *uffd_args = NULL;
+	struct uffd_desc **uffd_descs = NULL;
 	struct timespec start;
 	struct timespec ts_diff;
-	int *pipefds = NULL;
 	struct kvm_vm *vm;
-	int r, i;
+	int i;
 
 	vm = memstress_create_vm(mode, nr_vcpus, guest_percpu_mem_size, 1,
 				 p->src_type, p->partition_vcpu_memory_access);
@@ -296,15 +146,8 @@ static void run_test(enum vm_guest_mode mode, void *arg)
 	memset(guest_data_prototype, 0xAB, demand_paging_size);
 
 	if (p->uffd_mode) {
-		uffd_handler_threads =
-			malloc(nr_vcpus * sizeof(*uffd_handler_threads));
-		TEST_ASSERT(uffd_handler_threads, "Memory allocation failed");
-
-		uffd_args = malloc(nr_vcpus * sizeof(*uffd_args));
-		TEST_ASSERT(uffd_args, "Memory allocation failed");
-
-		pipefds = malloc(sizeof(int) * nr_vcpus * 2);
-		TEST_ASSERT(pipefds, "Unable to allocate memory for pipefd");
+		uffd_descs = malloc(nr_vcpus * sizeof(struct uffd_desc *));
+		TEST_ASSERT(uffd_descs, "Memory allocation failed");
 
 		for (i = 0; i < nr_vcpus; i++) {
 			struct memstress_vcpu_args *vcpu_args;
@@ -317,19 +160,17 @@ static void run_test(enum vm_guest_mode mode, void *arg)
 			vcpu_hva = addr_gpa2hva(vm, vcpu_args->gpa);
 			vcpu_alias = addr_gpa2alias(vm, vcpu_args->gpa);
 
+			prefault_mem(vcpu_alias,
+				vcpu_args->pages * memstress_args.guest_page_size);
+
 			/*
 			 * Set up user fault fd to handle demand paging
 			 * requests.
 			 */
-			r = pipe2(&pipefds[i * 2],
-				  O_CLOEXEC | O_NONBLOCK);
-			TEST_ASSERT(!r, "Failed to set up pipefd");
-
-			setup_demand_paging(vm, &uffd_handler_threads[i],
-					    pipefds[i * 2], p->uffd_mode,
-					    p->uffd_delay, &uffd_args[i],
-					    vcpu_hva, vcpu_alias,
-					    vcpu_args->pages * memstress_args.guest_page_size);
+			uffd_descs[i] = uffd_setup_demand_paging(
+				p->uffd_mode, p->uffd_delay, vcpu_hva,
+				vcpu_args->pages * memstress_args.guest_page_size,
+				&handle_uffd_page_request);
 		}
 	}
 
@@ -344,15 +185,9 @@ static void run_test(enum vm_guest_mode mode, void *arg)
 	pr_info("All vCPU threads joined\n");
 
 	if (p->uffd_mode) {
-		char c;
-
 		/* Tell the user fault fd handler threads to quit */
-		for (i = 0; i < nr_vcpus; i++) {
-			r = write(pipefds[i * 2 + 1], &c, 1);
-			TEST_ASSERT(r == 1, "Unable to write to pipefd");
-
-			pthread_join(uffd_handler_threads[i], NULL);
-		}
+		for (i = 0; i < nr_vcpus; i++)
+			uffd_stop_demand_paging(uffd_descs[i]);
 	}
 
 	pr_info("Total guest execution time: %ld.%.9lds\n",
@@ -364,11 +199,8 @@ static void run_test(enum vm_guest_mode mode, void *arg)
 	memstress_destroy_vm(vm);
 
 	free(guest_data_prototype);
-	if (p->uffd_mode) {
-		free(uffd_handler_threads);
-		free(uffd_args);
-		free(pipefds);
-	}
+	if (p->uffd_mode)
+		free(uffd_descs);
 }
 
 static void help(char *name)