Merge branch kvm-arm64/selftest/s2-faults into kvmarm-master/next

* kvm-arm64/selftest/s2-faults:
  : .
  : New KVM/arm64 selftests exercising various sorts of S2 faults, courtesy
  : of Ricardo Koller. From the cover letter:
  :
  : "This series adds a new aarch64 selftest for testing stage 2 fault handling
  : for various combinations of guest accesses (e.g., write, S1PTW), backing
  : sources (e.g., anon), and types of faults (e.g., read on hugetlbfs with a
  : hole, write on a readonly memslot). Each test tries a different combination
  : and then checks that the access results in the right behavior (e.g., uffd
  : faults with the right address and write/read flag). [...]"
  : .
  KVM: selftests: aarch64: Add mix of tests into page_fault_test
  KVM: selftests: aarch64: Add readonly memslot tests into page_fault_test
  KVM: selftests: aarch64: Add dirty logging tests into page_fault_test
  KVM: selftests: aarch64: Add userfaultfd tests into page_fault_test
  KVM: selftests: aarch64: Add aarch64/page_fault_test
  KVM: selftests: Use the right memslot for code, page-tables, and data allocations
  KVM: selftests: Fix alignment in virt_arch_pgd_alloc() and vm_vaddr_alloc()
  KVM: selftests: Add vm->memslots[] and enum kvm_mem_region_type
  KVM: selftests: Stash backing_src_type in struct userspace_mem_region
  tools: Copy bitfield.h from the kernel sources
  KVM: selftests: aarch64: Construct DEFAULT_MAIR_EL1 using sysreg.h macros
  KVM: selftests: Add missing close and munmap in __vm_mem_region_delete()
  KVM: selftests: aarch64: Add virt_get_pte_hva() library function
  KVM: selftests: Add a userfaultfd library

Signed-off-by: Marc Zyngier <maz@kernel.org>

1 files changed, 186 insertions, 0 deletions

diff --git a/tools/testing/selftests/kvm/lib/userfaultfd_util.c b/tools/testing/selftests/kvm/lib/userfaultfd_util.c
new file mode 100644
index 000000000000..3b44846fc277
--- /dev/null
+++ b/tools/testing/selftests/kvm/lib/userfaultfd_util.c
@@ -0,0 +1,186 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KVM userfaultfd util
+ * Adapted from demand_paging_test.c
+ *
+ * Copyright (C) 2018, Red Hat, Inc.
+ * Copyright (C) 2019-2022 Google LLC
+ */
+
+#define _GNU_SOURCE /* for pipe2 */
+
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <poll.h>
+#include <pthread.h>
+#include <linux/userfaultfd.h>
+#include <sys/syscall.h>
+
+#include "kvm_util.h"
+#include "test_util.h"
+#include "perf_test_util.h"
+#include "userfaultfd_util.h"
+
+#ifdef __NR_userfaultfd
+
+static void *uffd_handler_thread_fn(void *arg)
+{
+	struct uffd_desc *uffd_desc = (struct uffd_desc *)arg;
+	int uffd = uffd_desc->uffd;
+	int pipefd = uffd_desc->pipefds[0];
+	useconds_t delay = uffd_desc->delay;
+	int64_t pages = 0;
+	struct timespec start;
+	struct timespec ts_diff;
+
+	clock_gettime(CLOCK_MONOTONIC, &start);
+	while (1) {
+		struct uffd_msg msg;
+		struct pollfd pollfd[2];
+		char tmp_chr;
+		int r;
+
+		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);
+		r = uffd_desc->handler(uffd_desc->uffd_mode, uffd, &msg);
+		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;
+}
+
+struct uffd_desc *uffd_setup_demand_paging(int uffd_mode, useconds_t delay,
+					   void *hva, uint64_t len,
+					   uffd_handler_t handler)
+{
+	struct uffd_desc *uffd_desc;
+	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;
+
+	PER_PAGE_DEBUG("Userfaultfd %s mode, faults resolved with %s\n",
+		       is_minor ? "MINOR" : "MISSING",
+		       is_minor ? "UFFDIO_CONINUE" : "UFFDIO_COPY");
+
+	uffd_desc = malloc(sizeof(struct uffd_desc));
+	TEST_ASSERT(uffd_desc, "malloc failed");
+
+	/* In order to get minor faults, prefault via the alias. */
+	if (is_minor)
+		expected_ioctls = ((uint64_t) 1) << _UFFDIO_CONTINUE;
+
+	uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
+	TEST_ASSERT(uffd >= 0, "uffd creation failed, errno: %d", errno);
+
+	uffdio_api.api = UFFD_API;
+	uffdio_api.features = 0;
+	TEST_ASSERT(ioctl(uffd, UFFDIO_API, &uffdio_api) != -1,
+		    "ioctl UFFDIO_API failed: %" PRIu64,
+		    (uint64_t)uffdio_api.api);
+
+	uffdio_register.range.start = (uint64_t)hva;
+	uffdio_register.range.len = len;
+	uffdio_register.mode = uffd_mode;
+	TEST_ASSERT(ioctl(uffd, UFFDIO_REGISTER, &uffdio_register) != -1,
+		    "ioctl UFFDIO_REGISTER failed");
+	TEST_ASSERT((uffdio_register.ioctls & expected_ioctls) ==
+		    expected_ioctls, "missing userfaultfd ioctls");
+
+	ret = pipe2(uffd_desc->pipefds, O_CLOEXEC | O_NONBLOCK);
+	TEST_ASSERT(!ret, "Failed to set up pipefd");
+
+	uffd_desc->uffd_mode = uffd_mode;
+	uffd_desc->uffd = uffd;
+	uffd_desc->delay = delay;
+	uffd_desc->handler = handler;
+	pthread_create(&uffd_desc->thread, NULL, uffd_handler_thread_fn,
+		       uffd_desc);
+
+	PER_VCPU_DEBUG("Created uffd thread for HVA range [%p, %p)\n",
+		       hva, hva + len);
+
+	return uffd_desc;
+}
+
+void uffd_stop_demand_paging(struct uffd_desc *uffd)
+{
+	char c = 0;
+	int ret;
+
+	ret = write(uffd->pipefds[1], &c, 1);
+	TEST_ASSERT(ret == 1, "Unable to write to pipefd");
+
+	ret = pthread_join(uffd->thread, NULL);
+	TEST_ASSERT(ret == 0, "Pthread_join failed.");
+
+	close(uffd->uffd);
+
+	close(uffd->pipefds[1]);
+	close(uffd->pipefds[0]);
+
+	free(uffd);
+}
+
+#endif /* __NR_userfaultfd */