[PATCH v6 00/13] KVM: selftests: Add aarch64/page_fault_test

[PATCH v6 00/13] KVM: selftests: Add aarch64/page_fault_test

[Ricardo Koller]

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). Some interesting combinations are:

- loading an instruction leads to a stage 1 page-table-walk that misses on
  stage 2 because the backing memslot for the page table it not in host memory
  (a hole was punched right there) and the fault is handled using userfaultfd.
  The expected behavior is that this leads to a userfaultfd fault marked as a
  write. See commit c4ad98e4b72c ("KVM: arm64: Assume write fault on S1PTW
  permission fault on instruction fetch") for why that's a write.
- a cas (compare-and-swap) on a readonly memslot leads to a failed vcpu run.
- write-faulting on a memslot that's marked for userfaultfd handling and dirty
  logging should result in a uffd fault and having the respective bit set in
  the dirty log.

The first 8 commits of this series add library support. The first one adds a
new userfaultfd library (out of demand_paging_test.c). The next 3 add some
library functions to get the GPA of a PTE, and to get the fd of a backing
source. Commit 6 fixes a leaked fd when using shared backing stores. The last 5
commits add the new selftest, one type of test at a time. It first adds core
tests, then uffd, then dirty logging, then readonly memslots tests, and finally
combinations of the previous ones (like uffd and dirty logging at the same
time).

v5 -> v6: https://lore.kernel.org/kvmarm/20220823234727.621535-1-ricarkol@google.com/
- added "enum memslot_type" and all the related cleanups due to it [Andrew]
- default kvm_vm_mem_default with size=0 [Andrew,Sean]
- __vm_vaddr_alloc() taking "enum memslot_type" and all the related cleanups
  due to this change [Andrew]

v4 -> v5: https://lore.kernel.org/kvmarm/20220624213257.1504783-1-ricarkol@google.com/
- biggest change: followed suggestion from Sean and Andrew regarding a new
  arg for vm_create() to specify the guest memory layout. That's taken care
  of with these two new commits:
	KVM: selftests: Use the right memslot for code, page-tables, and data allocations
	KVM: selftests: Change ____vm_create() to take struct kvm_vm_mem_params
  plus the respective changes in the page_fault_test itself (mostly code reduction).
- dropped some commits that are not needed after the above change:
	KVM: selftests: aarch64: Export _virt_pg_map with a pt_memslot arg
	KVM: selftests: Add vm_alloc_page_table_in_memslot library function
	KVM: selftests: Add vm_mem_region_get_src_fd library function
- addressed Oliver comments in commit "KVM: selftests: aarch64: Add
  aarch64/page_fault_test"
- collect r-b's from Andrew

v3 -> v4: https://lore.kernel.org/kvmarm/20220408004120.1969099-1-ricarkol@google.com/
- rebased on top of latest kvm/queue.
- addressed Oliver comments: vm_get_pte_gpa rename, page_fault_test and
  other nits.
- adding MAIR entry for MT_DEVICE_nGnRnE. The value and indices are both
  0, so the change is really esthetic.

Ricardo Koller (13):
  KVM: selftests: Add a userfaultfd library
  KVM: selftests: aarch64: Add virt_get_pte_hva() library function
  KVM: selftests: Add missing close and munmap in
    __vm_mem_region_delete()
  KVM: selftests: aarch64: Construct DEFAULT_MAIR_EL1 using sysreg.h
    macros
  tools: Copy bitfield.h from the kernel sources
  KVM: selftests: Stash backing_src_type in struct userspace_mem_region
  KVM: selftests: Change ____vm_create() to take struct
    kvm_vm_mem_params
  KVM: selftests: Use the right memslot for code, page-tables, and data
    allocations
  KVM: selftests: aarch64: Add aarch64/page_fault_test
  KVM: selftests: aarch64: Add userfaultfd tests into page_fault_test
  KVM: selftests: aarch64: Add dirty logging tests into page_fault_test
  KVM: selftests: aarch64: Add readonly memslot tests into
    page_fault_test
  KVM: selftests: aarch64: Add mix of tests into page_fault_test

 tools/include/linux/bitfield.h                |  176 +++
 tools/testing/selftests/kvm/Makefile          |    2 +
 .../selftests/kvm/aarch64/page_fault_test.c   | 1137 +++++++++++++++++
 .../selftests/kvm/demand_paging_test.c        |  228 +---
 .../selftests/kvm/include/aarch64/processor.h |   35 +-
 .../selftests/kvm/include/kvm_util_base.h     |   55 +-
 .../selftests/kvm/include/userfaultfd_util.h  |   46 +
 .../selftests/kvm/lib/aarch64/processor.c     |   29 +-
 tools/testing/selftests/kvm/lib/elf.c         |    3 +-
 tools/testing/selftests/kvm/lib/kvm_util.c    |  122 +-
 .../selftests/kvm/lib/riscv/processor.c       |    7 +-
 .../selftests/kvm/lib/s390x/processor.c       |    7 +-
 .../selftests/kvm/lib/userfaultfd_util.c      |  187 +++
 .../selftests/kvm/lib/x86_64/processor.c      |   13 +-
 14 files changed, 1789 insertions(+), 258 deletions(-)
 create mode 100644 tools/include/linux/bitfield.h
 create mode 100644 tools/testing/selftests/kvm/aarch64/page_fault_test.c
 create mode 100644 tools/testing/selftests/kvm/include/userfaultfd_util.h
 create mode 100644 tools/testing/selftests/kvm/lib/userfaultfd_util.c

-- 
2.37.2.789.g6183377224-goog

[PATCH v6 01/13] KVM: selftests: Add a userfaultfd library

[Ricardo Koller]

Move the generic userfaultfd code out of demand_paging_test.c into a
common library, userfaultfd_util. This library consists of a setup and a
stop function. The setup function starts a thread for handling page
faults using the handler callback function. This setup returns a
uffd_desc object which is then used in the stop function (to wait and
destroy the threads).

Reviewed-by: Ben Gardon <bgardon@google.com>
Signed-off-by: Ricardo Koller <ricarkol@google.com>
---
 tools/testing/selftests/kvm/Makefile          |   1 +
 .../selftests/kvm/demand_paging_test.c        | 228 +++---------------
 .../selftests/kvm/include/userfaultfd_util.h  |  46 ++++
 .../selftests/kvm/lib/userfaultfd_util.c      | 187 ++++++++++++++
 4 files changed, 264 insertions(+), 198 deletions(-)
 create mode 100644 tools/testing/selftests/kvm/include/userfaultfd_util.h
 create mode 100644 tools/testing/selftests/kvm/lib/userfaultfd_util.c

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 4c122f1b1737..1bb471aeb103 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -47,6 +47,7 @@ LIBKVM += lib/perf_test_util.c
 LIBKVM += lib/rbtree.c
 LIBKVM += lib/sparsebit.c
 LIBKVM += lib/test_util.c
+LIBKVM += lib/userfaultfd_util.c
 
 LIBKVM_x86_64 += lib/x86_64/apic.c
 LIBKVM_x86_64 += lib/x86_64/handlers.S
diff --git a/tools/testing/selftests/kvm/demand_paging_test.c b/tools/testing/selftests/kvm/demand_paging_test.c
index 779ae54f89c4..8e1fe4ffcccd 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 "perf_test_util.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 perf_test_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 = perf_test_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 perf_test_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 * perf_test_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 * perf_test_args.guest_page_size);
+			uffd_descs[i] = uffd_setup_demand_paging(
+				p->uffd_mode, p->uffd_delay, vcpu_hva,
+				vcpu_args->pages * perf_test_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)
 	perf_test_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)
diff --git a/tools/testing/selftests/kvm/include/userfaultfd_util.h b/tools/testing/selftests/kvm/include/userfaultfd_util.h
new file mode 100644
index 000000000000..a1a386c083b0
--- /dev/null
+++ b/tools/testing/selftests/kvm/include/userfaultfd_util.h
@@ -0,0 +1,46 @@
+// 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 <time.h>
+#include <pthread.h>
+#include <linux/userfaultfd.h>
+
+#include "test_util.h"
+
+typedef int (*uffd_handler_t)(int uffd_mode, int uffd, struct uffd_msg *msg);
+
+struct uffd_desc {
+	int uffd_mode;
+	int uffd;
+	int pipefds[2];
+	useconds_t delay;
+	uffd_handler_t handler;
+	pthread_t thread;
+};
+
+struct uffd_desc *uffd_setup_demand_paging(int uffd_mode,
+		useconds_t uffd_delay, void *hva, uint64_t len,
+		uffd_handler_t handler);
+
+void uffd_stop_demand_paging(struct uffd_desc *uffd);
+
+#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
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..4395032ccbe4
--- /dev/null
+++ b/tools/testing/selftests/kvm/lib/userfaultfd_util.c
@@ -0,0 +1,187 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KVM userfaultfd util
+ * Adapted from demand_paging_test.c
+ *
+ * Copyright (C) 2018, Red Hat, Inc.
+ * Copyright (C) 2019, Google, Inc.
+ * Copyright (C) 2022, Google, Inc.
+ */
+
+#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 uffd_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 = uffd_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 */
-- 
2.37.2.789.g6183377224-goog

[PATCH v6 02/13] KVM: selftests: aarch64: Add virt_get_pte_hva() library function

[Ricardo Koller]

Add a library function to get the PTE (a host virtual address) of a
given GVA.  This will be used in a future commit by a test to clear and
check the access flag of a particular page.

Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Signed-off-by: Ricardo Koller <ricarkol@google.com>
---
 .../selftests/kvm/include/aarch64/processor.h       |  2 ++
 tools/testing/selftests/kvm/lib/aarch64/processor.c | 13 ++++++++++---
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/aarch64/processor.h b/tools/testing/selftests/kvm/include/aarch64/processor.h
index a8124f9dd68a..df4bfac69551 100644
--- a/tools/testing/selftests/kvm/include/aarch64/processor.h
+++ b/tools/testing/selftests/kvm/include/aarch64/processor.h
@@ -109,6 +109,8 @@ void vm_install_exception_handler(struct kvm_vm *vm,
 void vm_install_sync_handler(struct kvm_vm *vm,
 		int vector, int ec, handler_fn handler);
 
+uint64_t *virt_get_pte_hva(struct kvm_vm *vm, vm_vaddr_t gva);
+
 static inline void cpu_relax(void)
 {
 	asm volatile("yield" ::: "memory");
diff --git a/tools/testing/selftests/kvm/lib/aarch64/processor.c b/tools/testing/selftests/kvm/lib/aarch64/processor.c
index 6f5551368944..63ef3c78e55e 100644
--- a/tools/testing/selftests/kvm/lib/aarch64/processor.c
+++ b/tools/testing/selftests/kvm/lib/aarch64/processor.c
@@ -138,7 +138,7 @@ void virt_arch_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr)
 	_virt_pg_map(vm, vaddr, paddr, attr_idx);
 }
 
-vm_paddr_t addr_arch_gva2gpa(struct kvm_vm *vm, vm_vaddr_t gva)
+uint64_t *virt_get_pte_hva(struct kvm_vm *vm, vm_vaddr_t gva)
 {
 	uint64_t *ptep;
 
@@ -169,11 +169,18 @@ vm_paddr_t addr_arch_gva2gpa(struct kvm_vm *vm, vm_vaddr_t gva)
 		TEST_FAIL("Page table levels must be 2, 3, or 4");
 	}
 
-	return pte_addr(vm, *ptep) + (gva & (vm->page_size - 1));
+	return ptep;
 
 unmapped_gva:
 	TEST_FAIL("No mapping for vm virtual address, gva: 0x%lx", gva);
-	exit(1);
+	exit(EXIT_FAILURE);
+}
+
+vm_paddr_t addr_arch_gva2gpa(struct kvm_vm *vm, vm_vaddr_t gva)
+{
+	uint64_t *ptep = virt_get_pte_hva(vm, gva);
+
+	return pte_addr(vm, *ptep) + (gva & (vm->page_size - 1));
 }
 
 static void pte_dump(FILE *stream, struct kvm_vm *vm, uint8_t indent, uint64_t page, int level)
-- 
2.37.2.789.g6183377224-goog

[PATCH v6 03/13] KVM: selftests: Add missing close and munmap in __vm_mem_region_delete()

[Ricardo Koller]

Deleting a memslot (when freeing a VM) is not closing the backing fd,
nor it's unmapping the alias mapping. Fix by adding the missing close
and munmap.

Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Reviewed-by: Oliver Upton <oupton@google.com>
Reviewed-by: Ben Gardon <bgardon@google.com>
Signed-off-by: Ricardo Koller <ricarkol@google.com>
---
 tools/testing/selftests/kvm/lib/kvm_util.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 9889fe0d8919..9dd03eda2eb9 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -544,6 +544,12 @@ static void __vm_mem_region_delete(struct kvm_vm *vm,
 	sparsebit_free(&region->unused_phy_pages);
 	ret = munmap(region->mmap_start, region->mmap_size);
 	TEST_ASSERT(!ret, __KVM_SYSCALL_ERROR("munmap()", ret));
+	if (region->fd >= 0) {
+		/* There's an extra map when using shared memory. */
+		ret = munmap(region->mmap_alias, region->mmap_size);
+		TEST_ASSERT(!ret, __KVM_SYSCALL_ERROR("munmap()", ret));
+		close(region->fd);
+	}
 
 	free(region);
 }
-- 
2.37.2.789.g6183377224-goog

[PATCH v6 04/13] KVM: selftests: aarch64: Construct DEFAULT_MAIR_EL1 using sysreg.h macros

[Ricardo Koller]

Define macros for memory type indexes and construct DEFAULT_MAIR_EL1
with macros from asm/sysreg.h.  The index macros can then be used when
constructing PTEs (instead of using raw numbers).

Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Reviewed-by: Oliver Upton <oupton@google.com>
Signed-off-by: Ricardo Koller <ricarkol@google.com>
---
 .../selftests/kvm/include/aarch64/processor.h | 25 ++++++++++++++-----
 .../selftests/kvm/lib/aarch64/processor.c     |  2 +-
 2 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/aarch64/processor.h b/tools/testing/selftests/kvm/include/aarch64/processor.h
index df4bfac69551..c1ddca8db225 100644
--- a/tools/testing/selftests/kvm/include/aarch64/processor.h
+++ b/tools/testing/selftests/kvm/include/aarch64/processor.h
@@ -38,12 +38,25 @@
  * NORMAL             4     1111:1111
  * NORMAL_WT          5     1011:1011
  */
-#define DEFAULT_MAIR_EL1 ((0x00ul << (0 * 8)) | \
-			  (0x04ul << (1 * 8)) | \
-			  (0x0cul << (2 * 8)) | \
-			  (0x44ul << (3 * 8)) | \
-			  (0xfful << (4 * 8)) | \
-			  (0xbbul << (5 * 8)))
+
+/* Linux doesn't use these memory types, so let's define them. */
+#define MAIR_ATTR_DEVICE_GRE	UL(0x0c)
+#define MAIR_ATTR_NORMAL_WT	UL(0xbb)
+
+#define MT_DEVICE_nGnRnE	0
+#define MT_DEVICE_nGnRE		1
+#define MT_DEVICE_GRE		2
+#define MT_NORMAL_NC		3
+#define MT_NORMAL		4
+#define MT_NORMAL_WT		5
+
+#define DEFAULT_MAIR_EL1							\
+	(MAIR_ATTRIDX(MAIR_ATTR_DEVICE_nGnRnE, MT_DEVICE_nGnRnE) |		\
+	 MAIR_ATTRIDX(MAIR_ATTR_DEVICE_nGnRE, MT_DEVICE_nGnRE) |		\
+	 MAIR_ATTRIDX(MAIR_ATTR_DEVICE_GRE, MT_DEVICE_GRE) |			\
+	 MAIR_ATTRIDX(MAIR_ATTR_NORMAL_NC, MT_NORMAL_NC) |			\
+	 MAIR_ATTRIDX(MAIR_ATTR_NORMAL, MT_NORMAL) |				\
+	 MAIR_ATTRIDX(MAIR_ATTR_NORMAL_WT, MT_NORMAL_WT))
 
 #define MPIDR_HWID_BITMASK (0xff00fffffful)
 
diff --git a/tools/testing/selftests/kvm/lib/aarch64/processor.c b/tools/testing/selftests/kvm/lib/aarch64/processor.c
index 63ef3c78e55e..26f0eccff6fe 100644
--- a/tools/testing/selftests/kvm/lib/aarch64/processor.c
+++ b/tools/testing/selftests/kvm/lib/aarch64/processor.c
@@ -133,7 +133,7 @@ static void _virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr,
 
 void virt_arch_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr)
 {
-	uint64_t attr_idx = 4; /* NORMAL (See DEFAULT_MAIR_EL1) */
+	uint64_t attr_idx = MT_NORMAL;
 
 	_virt_pg_map(vm, vaddr, paddr, attr_idx);
 }
-- 
2.37.2.789.g6183377224-goog

[PATCH v6 05/13] tools: Copy bitfield.h from the kernel sources

[Ricardo Koller]

Copy bitfield.h from include/linux/bitfield.h.  A subsequent change will
make use of some FIELD_{GET,PREP} macros defined in this header.

The header was copied as-is, no changes needed.

Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Reviewed-by: Oliver Upton <oupton@google.com>
Signed-off-by: Ricardo Koller <ricarkol@google.com>
---
 tools/include/linux/bitfield.h | 176 +++++++++++++++++++++++++++++++++
 1 file changed, 176 insertions(+)
 create mode 100644 tools/include/linux/bitfield.h

diff --git a/tools/include/linux/bitfield.h b/tools/include/linux/bitfield.h
new file mode 100644
index 000000000000..6093fa6db260
--- /dev/null
+++ b/tools/include/linux/bitfield.h
@@ -0,0 +1,176 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2014 Felix Fietkau <nbd@nbd.name>
+ * Copyright (C) 2004 - 2009 Ivo van Doorn <IvDoorn@gmail.com>
+ */
+
+#ifndef _LINUX_BITFIELD_H
+#define _LINUX_BITFIELD_H
+
+#include <linux/build_bug.h>
+#include <asm/byteorder.h>
+
+/*
+ * Bitfield access macros
+ *
+ * FIELD_{GET,PREP} macros take as first parameter shifted mask
+ * from which they extract the base mask and shift amount.
+ * Mask must be a compilation time constant.
+ *
+ * Example:
+ *
+ *  #define REG_FIELD_A  GENMASK(6, 0)
+ *  #define REG_FIELD_B  BIT(7)
+ *  #define REG_FIELD_C  GENMASK(15, 8)
+ *  #define REG_FIELD_D  GENMASK(31, 16)
+ *
+ * Get:
+ *  a = FIELD_GET(REG_FIELD_A, reg);
+ *  b = FIELD_GET(REG_FIELD_B, reg);
+ *
+ * Set:
+ *  reg = FIELD_PREP(REG_FIELD_A, 1) |
+ *	  FIELD_PREP(REG_FIELD_B, 0) |
+ *	  FIELD_PREP(REG_FIELD_C, c) |
+ *	  FIELD_PREP(REG_FIELD_D, 0x40);
+ *
+ * Modify:
+ *  reg &= ~REG_FIELD_C;
+ *  reg |= FIELD_PREP(REG_FIELD_C, c);
+ */
+
+#define __bf_shf(x) (__builtin_ffsll(x) - 1)
+
+#define __scalar_type_to_unsigned_cases(type)				\
+		unsigned type:	(unsigned type)0,			\
+		signed type:	(unsigned type)0
+
+#define __unsigned_scalar_typeof(x) typeof(				\
+		_Generic((x),						\
+			char:	(unsigned char)0,			\
+			__scalar_type_to_unsigned_cases(char),		\
+			__scalar_type_to_unsigned_cases(short),		\
+			__scalar_type_to_unsigned_cases(int),		\
+			__scalar_type_to_unsigned_cases(long),		\
+			__scalar_type_to_unsigned_cases(long long),	\
+			default: (x)))
+
+#define __bf_cast_unsigned(type, x)	((__unsigned_scalar_typeof(type))(x))
+
+#define __BF_FIELD_CHECK(_mask, _reg, _val, _pfx)			\
+	({								\
+		BUILD_BUG_ON_MSG(!__builtin_constant_p(_mask),		\
+				 _pfx "mask is not constant");		\
+		BUILD_BUG_ON_MSG((_mask) == 0, _pfx "mask is zero");	\
+		BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ?		\
+				 ~((_mask) >> __bf_shf(_mask)) & (_val) : 0, \
+				 _pfx "value too large for the field"); \
+		BUILD_BUG_ON_MSG(__bf_cast_unsigned(_mask, _mask) >	\
+				 __bf_cast_unsigned(_reg, ~0ull),	\
+				 _pfx "type of reg too small for mask"); \
+		__BUILD_BUG_ON_NOT_POWER_OF_2((_mask) +			\
+					      (1ULL << __bf_shf(_mask))); \
+	})
+
+/**
+ * FIELD_MAX() - produce the maximum value representable by a field
+ * @_mask: shifted mask defining the field's length and position
+ *
+ * FIELD_MAX() returns the maximum value that can be held in the field
+ * specified by @_mask.
+ */
+#define FIELD_MAX(_mask)						\
+	({								\
+		__BF_FIELD_CHECK(_mask, 0ULL, 0ULL, "FIELD_MAX: ");	\
+		(typeof(_mask))((_mask) >> __bf_shf(_mask));		\
+	})
+
+/**
+ * FIELD_FIT() - check if value fits in the field
+ * @_mask: shifted mask defining the field's length and position
+ * @_val:  value to test against the field
+ *
+ * Return: true if @_val can fit inside @_mask, false if @_val is too big.
+ */
+#define FIELD_FIT(_mask, _val)						\
+	({								\
+		__BF_FIELD_CHECK(_mask, 0ULL, 0ULL, "FIELD_FIT: ");	\
+		!((((typeof(_mask))_val) << __bf_shf(_mask)) & ~(_mask)); \
+	})
+
+/**
+ * FIELD_PREP() - prepare a bitfield element
+ * @_mask: shifted mask defining the field's length and position
+ * @_val:  value to put in the field
+ *
+ * FIELD_PREP() masks and shifts up the value.  The result should
+ * be combined with other fields of the bitfield using logical OR.
+ */
+#define FIELD_PREP(_mask, _val)						\
+	({								\
+		__BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: ");	\
+		((typeof(_mask))(_val) << __bf_shf(_mask)) & (_mask);	\
+	})
+
+/**
+ * FIELD_GET() - extract a bitfield element
+ * @_mask: shifted mask defining the field's length and position
+ * @_reg:  value of entire bitfield
+ *
+ * FIELD_GET() extracts the field specified by @_mask from the
+ * bitfield passed in as @_reg by masking and shifting it down.
+ */
+#define FIELD_GET(_mask, _reg)						\
+	({								\
+		__BF_FIELD_CHECK(_mask, _reg, 0U, "FIELD_GET: ");	\
+		(typeof(_mask))(((_reg) & (_mask)) >> __bf_shf(_mask));	\
+	})
+
+extern void __compiletime_error("value doesn't fit into mask")
+__field_overflow(void);
+extern void __compiletime_error("bad bitfield mask")
+__bad_mask(void);
+static __always_inline u64 field_multiplier(u64 field)
+{
+	if ((field | (field - 1)) & ((field | (field - 1)) + 1))
+		__bad_mask();
+	return field & -field;
+}
+static __always_inline u64 field_mask(u64 field)
+{
+	return field / field_multiplier(field);
+}
+#define field_max(field)	((typeof(field))field_mask(field))
+#define ____MAKE_OP(type,base,to,from)					\
+static __always_inline __##type type##_encode_bits(base v, base field)	\
+{									\
+	if (__builtin_constant_p(v) && (v & ~field_mask(field)))	\
+		__field_overflow();					\
+	return to((v & field_mask(field)) * field_multiplier(field));	\
+}									\
+static __always_inline __##type type##_replace_bits(__##type old,	\
+					base val, base field)		\
+{									\
+	return (old & ~to(field)) | type##_encode_bits(val, field);	\
+}									\
+static __always_inline void type##p_replace_bits(__##type *p,		\
+					base val, base field)		\
+{									\
+	*p = (*p & ~to(field)) | type##_encode_bits(val, field);	\
+}									\
+static __always_inline base type##_get_bits(__##type v, base field)	\
+{									\
+	return (from(v) & field)/field_multiplier(field);		\
+}
+#define __MAKE_OP(size)							\
+	____MAKE_OP(le##size,u##size,cpu_to_le##size,le##size##_to_cpu)	\
+	____MAKE_OP(be##size,u##size,cpu_to_be##size,be##size##_to_cpu)	\
+	____MAKE_OP(u##size,u##size,,)
+____MAKE_OP(u8,u8,,)
+__MAKE_OP(16)
+__MAKE_OP(32)
+__MAKE_OP(64)
+#undef __MAKE_OP
+#undef ____MAKE_OP
+
+#endif
-- 
2.37.2.789.g6183377224-goog

[PATCH v6 06/13] KVM: selftests: Stash backing_src_type in struct userspace_mem_region

[Ricardo Koller]

Add the backing_src_type into struct userspace_mem_region. This struct already
stores a lot of info about memory regions, except the backing source type.
This info will be used by a future commit in order to determine the method for
punching a hole.

Signed-off-by: Ricardo Koller <ricarkol@google.com>
---
 tools/testing/selftests/kvm/include/kvm_util_base.h | 1 +
 tools/testing/selftests/kvm/lib/kvm_util.c          | 1 +
 2 files changed, 2 insertions(+)

diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
index 24fde97f6121..b2dbe253d4d0 100644
--- a/tools/testing/selftests/kvm/include/kvm_util_base.h
+++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
@@ -34,6 +34,7 @@ struct userspace_mem_region {
 	struct sparsebit *unused_phy_pages;
 	int fd;
 	off_t offset;
+	enum vm_mem_backing_src_type backing_src_type;
 	void *host_mem;
 	void *host_alias;
 	void *mmap_start;
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 9dd03eda2eb9..5a9f080ff888 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -887,6 +887,7 @@ void vm_userspace_mem_region_add(struct kvm_vm *vm,
 			    vm_mem_backing_src_alias(src_type)->name);
 	}
 
+	region->backing_src_type = src_type;
 	region->unused_phy_pages = sparsebit_alloc();
 	sparsebit_set_num(region->unused_phy_pages,
 		guest_paddr >> vm->page_shift, npages);
-- 
2.37.2.789.g6183377224-goog

[PATCH v6 07/13] KVM: selftests: Change ____vm_create() to take struct kvm_vm_mem_params

[Ricardo Koller]

The vm_create() helpers are hardcoded to place most page types (code,
page-tables, stacks, etc) in the same memslot #0, and always backed with
anonymous 4K.  There are a couple of issues with that.  First, tests willing to
differ a bit, like placing page-tables in a different backing source type must
replicate much of what's already done by the vm_create() functions.  Second,
the hardcoded assumption of memslot #0 holding most things is spreaded
everywhere; this makes it very hard to change.

Fix the above issues by having selftests specify how they want memory to be
laid out: define the memory regions to use for code, pt (page-tables), and
data. Introduce a new structure, struct kvm_vm_mem_params, that defines: guest
mode, a list of memory region descriptions, and some fields specifying what
regions to use for code, pt, and data.

There is no functional change intended. The current commit adds a default
struct kvm_vm_mem_params that lays out memory exactly as before. The next
commit will change the allocators to get the region they should be using,
e.g.,: like the page table allocators using the pt memslot.

Cc: Sean Christopherson <seanjc@google.com>
Cc: Andrew Jones <andrew.jones@linux.dev>
Signed-off-by: Ricardo Koller <ricarkol@google.com>
---
 .../selftests/kvm/include/kvm_util_base.h     | 51 +++++++++++++++-
 .../selftests/kvm/lib/aarch64/processor.c     |  3 +-
 tools/testing/selftests/kvm/lib/kvm_util.c    | 58 ++++++++++++++++---
 3 files changed, 102 insertions(+), 10 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
index b2dbe253d4d0..5dbca38a512b 100644
--- a/tools/testing/selftests/kvm/include/kvm_util_base.h
+++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
@@ -65,6 +65,13 @@ struct userspace_mem_regions {
 	DECLARE_HASHTABLE(slot_hash, 9);
 };
 
+enum kvm_mem_region_type {
+	MEM_REGION_CODE,
+	MEM_REGION_PT,
+	MEM_REGION_DATA,
+	NR_MEM_REGIONS,
+};
+
 struct kvm_vm {
 	int mode;
 	unsigned long type;
@@ -93,6 +100,13 @@ struct kvm_vm {
 	int stats_fd;
 	struct kvm_stats_header stats_header;
 	struct kvm_stats_desc *stats_desc;
+
+	/*
+	 * KVM region slots. These are the default memslots used by page
+	 * allocators, e.g., lib/elf uses the memslots[MEM_REGION_CODE]
+	 * memslot.
+	 */
+	uint32_t memslots[NR_MEM_REGIONS];
 };
 
 
@@ -105,6 +119,13 @@ struct kvm_vm {
 struct userspace_mem_region *
 memslot2region(struct kvm_vm *vm, uint32_t memslot);
 
+inline struct userspace_mem_region *
+vm_get_mem_region(struct kvm_vm *vm, enum kvm_mem_region_type mrt)
+{
+	assert(mrt < NR_MEM_REGIONS);
+	return memslot2region(vm, vm->memslots[mrt]);
+}
+
 /* Minimum allocated guest virtual and physical addresses */
 #define KVM_UTIL_MIN_VADDR		0x2000
 #define KVM_GUEST_PAGE_TABLE_MIN_PADDR	0x180000
@@ -637,19 +658,45 @@ vm_paddr_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
 			      vm_paddr_t paddr_min, uint32_t memslot);
 vm_paddr_t vm_alloc_page_table(struct kvm_vm *vm);
 
+struct kvm_vm_mem_params {
+	enum vm_guest_mode mode;
+
+	struct {
+		enum vm_mem_backing_src_type src_type;
+		uint64_t guest_paddr;
+		/*
+		 * KVM region slot (same meaning as in struct
+		 * kvm_userspace_memory_region).
+		 */
+		uint32_t slot;
+		uint64_t npages;
+		uint32_t flags;
+		bool enabled;
+	} region[NR_MEM_REGIONS];
+
+	/* Each region type points to a region in the above array. */
+	uint16_t region_idx[NR_MEM_REGIONS];
+};
+
+extern struct kvm_vm_mem_params kvm_vm_mem_default;
+
 /*
  * ____vm_create() does KVM_CREATE_VM and little else.  __vm_create() also
  * loads the test binary into guest memory and creates an IRQ chip (x86 only).
  * __vm_create() does NOT create vCPUs, @nr_runnable_vcpus is used purely to
  * calculate the amount of memory needed for per-vCPU data, e.g. stacks.
  */
-struct kvm_vm *____vm_create(enum vm_guest_mode mode, uint64_t nr_pages);
+struct kvm_vm *____vm_create(struct kvm_vm_mem_params *mem_params);
 struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus,
 			   uint64_t nr_extra_pages);
 
 static inline struct kvm_vm *vm_create_barebones(void)
 {
-	return ____vm_create(VM_MODE_DEFAULT, 0);
+	struct kvm_vm_mem_params params_wo_memslots = {
+		.mode = kvm_vm_mem_default.mode,
+	};
+
+	return ____vm_create(&params_wo_memslots);
 }
 
 static inline struct kvm_vm *vm_create(uint32_t nr_runnable_vcpus)
diff --git a/tools/testing/selftests/kvm/lib/aarch64/processor.c b/tools/testing/selftests/kvm/lib/aarch64/processor.c
index 26f0eccff6fe..5a31dc85d054 100644
--- a/tools/testing/selftests/kvm/lib/aarch64/processor.c
+++ b/tools/testing/selftests/kvm/lib/aarch64/processor.c
@@ -508,7 +508,8 @@ void aarch64_get_supported_page_sizes(uint32_t ipa,
  */
 void __attribute__((constructor)) init_guest_modes(void)
 {
-       guest_modes_append_default();
+	guest_modes_append_default();
+	kvm_vm_mem_default.mode = VM_MODE_DEFAULT;
 }
 
 void smccc_hvc(uint32_t function_id, uint64_t arg0, uint64_t arg1,
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 5a9f080ff888..02532bc528da 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -143,12 +143,37 @@ const struct vm_guest_mode_params vm_guest_mode_params[] = {
 _Static_assert(sizeof(vm_guest_mode_params)/sizeof(struct vm_guest_mode_params) == NUM_VM_MODES,
 	       "Missing new mode params?");
 
-struct kvm_vm *____vm_create(enum vm_guest_mode mode, uint64_t nr_pages)
+/*
+ * A single memslot #0 for code, data, and page tables.
+ *
+ * .region[0].npages should be set by the user.
+ */
+struct kvm_vm_mem_params kvm_vm_mem_default = {
+#ifndef __aarch64__
+	/* arm64 kvm_vm_mem_default.mode set in init_guest_modes() */
+	.mode = VM_MODE_DEFAULT,
+#endif
+	.region[0] = {
+		.src_type = VM_MEM_SRC_ANONYMOUS,
+		.guest_paddr = 0,
+		.slot = 0,
+		.npages = 0,
+		.flags = 0,
+		.enabled = true,
+	},
+	.region_idx[MEM_REGION_CODE] = 0,
+	.region_idx[MEM_REGION_PT] = 0,
+	.region_idx[MEM_REGION_DATA] = 0,
+};
+
+struct kvm_vm *____vm_create(struct kvm_vm_mem_params *mem_params)
 {
+	enum vm_guest_mode mode = mem_params->mode;
 	struct kvm_vm *vm;
+	enum kvm_mem_region_type mrt;
+	int idx;
 
-	pr_debug("%s: mode='%s' pages='%ld'\n", __func__,
-		 vm_guest_mode_string(mode), nr_pages);
+	pr_debug("%s: mode='%s'\n", __func__, vm_guest_mode_string(mode));
 
 	vm = calloc(1, sizeof(*vm));
 	TEST_ASSERT(vm != NULL, "Insufficient Memory");
@@ -245,9 +270,25 @@ struct kvm_vm *____vm_create(enum vm_guest_mode mode, uint64_t nr_pages)
 
 	/* Allocate and setup memory for guest. */
 	vm->vpages_mapped = sparsebit_alloc();
-	if (nr_pages != 0)
-		vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
-					    0, 0, nr_pages, 0);
+
+	/* Create all mem regions according to mem_params specifications. */
+	for (idx = 0; idx < NR_MEM_REGIONS; idx++) {
+		if (!mem_params->region[idx].enabled)
+			continue;
+
+		vm_userspace_mem_region_add(vm,
+			mem_params->region[idx].src_type,
+			mem_params->region[idx].guest_paddr,
+			mem_params->region[idx].slot,
+			mem_params->region[idx].npages,
+			mem_params->region[idx].flags);
+	}
+
+	/* Set all memslot types for the VM, also according to the spec. */
+	for (mrt = 0; mrt < NR_MEM_REGIONS; mrt++) {
+		idx = mem_params->region_idx[mrt];
+		vm->memslots[mrt] = mem_params->region[idx].slot;
+	}
 
 	return vm;
 }
@@ -292,9 +333,12 @@ struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus,
 {
 	uint64_t nr_pages = vm_nr_pages_required(mode, nr_runnable_vcpus,
 						 nr_extra_pages);
+	struct kvm_vm_mem_params mem_params = kvm_vm_mem_default;
 	struct kvm_vm *vm;
 
-	vm = ____vm_create(mode, nr_pages);
+	mem_params.region[0].npages = nr_pages;
+	mem_params.mode = mode;
+	vm = ____vm_create(&mem_params);
 
 	kvm_vm_elf_load(vm, program_invocation_name);
 
-- 
2.37.2.789.g6183377224-goog

[PATCH v6 08/13] KVM: selftests: Use the right memslot for code, page-tables, and data allocations

[Ricardo Koller]

The previous commit added support for callers of ____vm_create() to specify
what memslots to use for code, page-tables, and data allocations. Change
them accordingly:

- stacks, code, and exception tables use the code memslot
- page tables and the pgd use the pt memslot
- data (anything allocated with vm_vaddr_alloc()) uses the data memslot

No functional change intended. All allocators keep using memslot #0.

Cc: Sean Christopherson <seanjc@google.com>
Cc: Andrew Jones <andrew.jones@linux.dev>
Signed-off-by: Ricardo Koller <ricarkol@google.com>
---
 .../selftests/kvm/include/kvm_util_base.h     |  3 +
 .../selftests/kvm/lib/aarch64/processor.c     | 11 ++--
 tools/testing/selftests/kvm/lib/elf.c         |  3 +-
 tools/testing/selftests/kvm/lib/kvm_util.c    | 57 ++++++++++++-------
 .../selftests/kvm/lib/riscv/processor.c       |  7 ++-
 .../selftests/kvm/lib/s390x/processor.c       |  7 ++-
 .../selftests/kvm/lib/x86_64/processor.c      | 13 +++--
 7 files changed, 61 insertions(+), 40 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
index 5dbca38a512b..76a087a88efd 100644
--- a/tools/testing/selftests/kvm/include/kvm_util_base.h
+++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
@@ -402,7 +402,10 @@ void vm_mem_region_move(struct kvm_vm *vm, uint32_t slot, uint64_t new_gpa);
 void vm_mem_region_delete(struct kvm_vm *vm, uint32_t slot);
 struct kvm_vcpu *__vm_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id);
 vm_vaddr_t vm_vaddr_alloc(struct kvm_vm *vm, size_t sz, vm_vaddr_t vaddr_min);
+vm_vaddr_t __vm_vaddr_alloc(struct kvm_vm *vm, size_t sz,
+			    vm_vaddr_t vaddr_min, enum kvm_mem_region_type mr);
 vm_vaddr_t vm_vaddr_alloc_pages(struct kvm_vm *vm, int nr_pages);
+vm_vaddr_t __vm_vaddr_alloc_page(struct kvm_vm *vm, enum kvm_mem_region_type mr);
 vm_vaddr_t vm_vaddr_alloc_page(struct kvm_vm *vm);
 
 void virt_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr,
diff --git a/tools/testing/selftests/kvm/lib/aarch64/processor.c b/tools/testing/selftests/kvm/lib/aarch64/processor.c
index 5a31dc85d054..885b893a5f40 100644
--- a/tools/testing/selftests/kvm/lib/aarch64/processor.c
+++ b/tools/testing/selftests/kvm/lib/aarch64/processor.c
@@ -79,7 +79,7 @@ void virt_arch_pgd_alloc(struct kvm_vm *vm)
 	if (!vm->pgd_created) {
 		vm_paddr_t paddr = vm_phy_pages_alloc(vm,
 			page_align(vm, ptrs_per_pgd(vm) * 8) / vm->page_size,
-			KVM_GUEST_PAGE_TABLE_MIN_PADDR, 0);
+			KVM_GUEST_PAGE_TABLE_MIN_PADDR, vm->memslots[MEM_REGION_PT]);
 		vm->pgd = paddr;
 		vm->pgd_created = true;
 	}
@@ -328,8 +328,9 @@ struct kvm_vcpu *aarch64_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id,
 	size_t stack_size = vm->page_size == 4096 ?
 					DEFAULT_STACK_PGS * vm->page_size :
 					vm->page_size;
-	uint64_t stack_vaddr = vm_vaddr_alloc(vm, stack_size,
-					      DEFAULT_ARM64_GUEST_STACK_VADDR_MIN);
+	uint64_t stack_vaddr = __vm_vaddr_alloc(vm, stack_size,
+						DEFAULT_ARM64_GUEST_STACK_VADDR_MIN,
+						MEM_REGION_CODE);
 	struct kvm_vcpu *vcpu = __vm_vcpu_add(vm, vcpu_id);
 
 	aarch64_vcpu_setup(vcpu, init);
@@ -435,8 +436,8 @@ void route_exception(struct ex_regs *regs, int vector)
 
 void vm_init_descriptor_tables(struct kvm_vm *vm)
 {
-	vm->handlers = vm_vaddr_alloc(vm, sizeof(struct handlers),
-			vm->page_size);
+	vm->handlers = __vm_vaddr_alloc(vm, sizeof(struct handlers),
+					vm->page_size, MEM_REGION_CODE);
 
 	*(vm_vaddr_t *)addr_gva2hva(vm, (vm_vaddr_t)(&exception_handlers)) = vm->handlers;
 }
diff --git a/tools/testing/selftests/kvm/lib/elf.c b/tools/testing/selftests/kvm/lib/elf.c
index 9f54c098d9d0..51f280c412ba 100644
--- a/tools/testing/selftests/kvm/lib/elf.c
+++ b/tools/testing/selftests/kvm/lib/elf.c
@@ -161,7 +161,8 @@ void kvm_vm_elf_load(struct kvm_vm *vm, const char *filename)
 		seg_vend |= vm->page_size - 1;
 		size_t seg_size = seg_vend - seg_vstart + 1;
 
-		vm_vaddr_t vaddr = vm_vaddr_alloc(vm, seg_size, seg_vstart);
+		vm_vaddr_t vaddr = __vm_vaddr_alloc(vm, seg_size, seg_vstart,
+						    MEM_REGION_CODE);
 		TEST_ASSERT(vaddr == seg_vstart, "Unable to allocate "
 			"virtual memory for segment at requested min addr,\n"
 			"  segment idx: %u\n"
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 02532bc528da..ff457af44c53 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -1226,32 +1226,15 @@ static vm_vaddr_t vm_vaddr_unused_gap(struct kvm_vm *vm, size_t sz,
 	return pgidx_start * vm->page_size;
 }
 
-/*
- * VM Virtual Address Allocate
- *
- * Input Args:
- *   vm - Virtual Machine
- *   sz - Size in bytes
- *   vaddr_min - Minimum starting virtual address
- *
- * Output Args: None
- *
- * Return:
- *   Starting guest virtual address
- *
- * Allocates at least sz bytes within the virtual address space of the vm
- * given by vm.  The allocated bytes are mapped to a virtual address >=
- * the address given by vaddr_min.  Note that each allocation uses a
- * a unique set of pages, with the minimum real allocation being at least
- * a page.
- */
-vm_vaddr_t vm_vaddr_alloc(struct kvm_vm *vm, size_t sz, vm_vaddr_t vaddr_min)
+vm_vaddr_t __vm_vaddr_alloc(struct kvm_vm *vm, size_t sz,
+			    vm_vaddr_t vaddr_min, enum kvm_mem_region_type mrt)
 {
 	uint64_t pages = (sz >> vm->page_shift) + ((sz % vm->page_size) != 0);
 
 	virt_pgd_alloc(vm);
 	vm_paddr_t paddr = vm_phy_pages_alloc(vm, pages,
-					      KVM_UTIL_MIN_PFN * vm->page_size, 0);
+				KVM_UTIL_MIN_PFN * vm->page_size,
+				vm->memslots[mrt]);
 
 	/*
 	 * Find an unused range of virtual page addresses of at least
@@ -1272,6 +1255,30 @@ vm_vaddr_t vm_vaddr_alloc(struct kvm_vm *vm, size_t sz, vm_vaddr_t vaddr_min)
 	return vaddr_start;
 }
 
+/*
+ * VM Virtual Address Allocate
+ *
+ * Input Args:
+ *   vm - Virtual Machine
+ *   sz - Size in bytes
+ *   vaddr_min - Minimum starting virtual address
+ *
+ * Output Args: None
+ *
+ * Return:
+ *   Starting guest virtual address
+ *
+ * Allocates at least sz bytes within the virtual address space of the vm
+ * given by vm.  The allocated bytes are mapped to a virtual address >=
+ * the address given by vaddr_min.  Note that each allocation uses a
+ * a unique set of pages, with the minimum real allocation being at least
+ * a page. The allocated physical space comes from the data memory region.
+ */
+vm_vaddr_t vm_vaddr_alloc(struct kvm_vm *vm, size_t sz, vm_vaddr_t vaddr_min)
+{
+	return __vm_vaddr_alloc(vm, sz, vaddr_min, MEM_REGION_DATA);
+}
+
 /*
  * VM Virtual Address Allocate Pages
  *
@@ -1291,6 +1298,11 @@ vm_vaddr_t vm_vaddr_alloc_pages(struct kvm_vm *vm, int nr_pages)
 	return vm_vaddr_alloc(vm, nr_pages * getpagesize(), KVM_UTIL_MIN_VADDR);
 }
 
+vm_vaddr_t __vm_vaddr_alloc_page(struct kvm_vm *vm, enum kvm_mem_region_type mrt)
+{
+	return __vm_vaddr_alloc(vm, getpagesize(), KVM_UTIL_MIN_VADDR, mrt);
+}
+
 /*
  * VM Virtual Address Allocate Page
  *
@@ -1856,7 +1868,8 @@ vm_paddr_t vm_phy_page_alloc(struct kvm_vm *vm, vm_paddr_t paddr_min,
 
 vm_paddr_t vm_alloc_page_table(struct kvm_vm *vm)
 {
-	return vm_phy_page_alloc(vm, KVM_GUEST_PAGE_TABLE_MIN_PADDR, 0);
+	return vm_phy_page_alloc(vm, KVM_GUEST_PAGE_TABLE_MIN_PADDR,
+				 vm->memslots[MEM_REGION_PT]);
 }
 
 /*
diff --git a/tools/testing/selftests/kvm/lib/riscv/processor.c b/tools/testing/selftests/kvm/lib/riscv/processor.c
index 604478151212..26c8d3dffb9a 100644
--- a/tools/testing/selftests/kvm/lib/riscv/processor.c
+++ b/tools/testing/selftests/kvm/lib/riscv/processor.c
@@ -58,7 +58,7 @@ void virt_arch_pgd_alloc(struct kvm_vm *vm)
 	if (!vm->pgd_created) {
 		vm_paddr_t paddr = vm_phy_pages_alloc(vm,
 			page_align(vm, ptrs_per_pte(vm) * 8) / vm->page_size,
-			KVM_GUEST_PAGE_TABLE_MIN_PADDR, 0);
+			KVM_GUEST_PAGE_TABLE_MIN_PADDR, vm->memslots[MEM_REGION_PT]);
 		vm->pgd = paddr;
 		vm->pgd_created = true;
 	}
@@ -282,8 +282,9 @@ struct kvm_vcpu *vm_arch_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id,
 	size_t stack_size = vm->page_size == 4096 ?
 					DEFAULT_STACK_PGS * vm->page_size :
 					vm->page_size;
-	unsigned long stack_vaddr = vm_vaddr_alloc(vm, stack_size,
-					DEFAULT_RISCV_GUEST_STACK_VADDR_MIN);
+	unsigned long stack_vaddr = __vm_vaddr_alloc(vm, stack_size,
+					DEFAULT_RISCV_GUEST_STACK_VADDR_MIN,
+					MEM_REGION_CODE);
 	unsigned long current_gp = 0;
 	struct kvm_mp_state mps;
 	struct kvm_vcpu *vcpu;
diff --git a/tools/testing/selftests/kvm/lib/s390x/processor.c b/tools/testing/selftests/kvm/lib/s390x/processor.c
index 89d7340d9cbd..410ae2b59847 100644
--- a/tools/testing/selftests/kvm/lib/s390x/processor.c
+++ b/tools/testing/selftests/kvm/lib/s390x/processor.c
@@ -21,7 +21,7 @@ void virt_arch_pgd_alloc(struct kvm_vm *vm)
 		return;
 
 	paddr = vm_phy_pages_alloc(vm, PAGES_PER_REGION,
-				   KVM_GUEST_PAGE_TABLE_MIN_PADDR, 0);
+			KVM_GUEST_PAGE_TABLE_MIN_PADDR, vm->memslots[MEM_REGION_PT]);
 	memset(addr_gpa2hva(vm, paddr), 0xff, PAGES_PER_REGION * vm->page_size);
 
 	vm->pgd = paddr;
@@ -167,8 +167,9 @@ struct kvm_vcpu *vm_arch_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id,
 	TEST_ASSERT(vm->page_size == 4096, "Unsupported page size: 0x%x",
 		    vm->page_size);
 
-	stack_vaddr = vm_vaddr_alloc(vm, stack_size,
-				     DEFAULT_GUEST_STACK_VADDR_MIN);
+	stack_vaddr = __vm_vaddr_alloc(vm, stack_size,
+				       DEFAULT_GUEST_STACK_VADDR_MIN,
+				       MEM_REGION_CODE);
 
 	vcpu = __vm_vcpu_add(vm, vcpu_id);
 
diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index 2e6e61bbe81b..f7b90a6c7d19 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -525,7 +525,7 @@ vm_paddr_t addr_arch_gva2gpa(struct kvm_vm *vm, vm_vaddr_t gva)
 static void kvm_setup_gdt(struct kvm_vm *vm, struct kvm_dtable *dt)
 {
 	if (!vm->gdt)
-		vm->gdt = vm_vaddr_alloc_page(vm);
+		vm->gdt = __vm_vaddr_alloc_page(vm, MEM_REGION_CODE);
 
 	dt->base = vm->gdt;
 	dt->limit = getpagesize();
@@ -535,7 +535,7 @@ static void kvm_setup_tss_64bit(struct kvm_vm *vm, struct kvm_segment *segp,
 				int selector)
 {
 	if (!vm->tss)
-		vm->tss = vm_vaddr_alloc_page(vm);
+		vm->tss = __vm_vaddr_alloc_page(vm, MEM_REGION_CODE);
 
 	memset(segp, 0, sizeof(*segp));
 	segp->base = vm->tss;
@@ -620,8 +620,9 @@ struct kvm_vcpu *vm_arch_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id,
 	vm_vaddr_t stack_vaddr;
 	struct kvm_vcpu *vcpu;
 
-	stack_vaddr = vm_vaddr_alloc(vm, DEFAULT_STACK_PGS * getpagesize(),
-				     DEFAULT_GUEST_STACK_VADDR_MIN);
+	stack_vaddr = __vm_vaddr_alloc(vm, DEFAULT_STACK_PGS * getpagesize(),
+				       DEFAULT_GUEST_STACK_VADDR_MIN,
+				       MEM_REGION_CODE);
 
 	vcpu = __vm_vcpu_add(vm, vcpu_id);
 	vcpu_init_cpuid(vcpu, kvm_get_supported_cpuid());
@@ -1118,8 +1119,8 @@ void vm_init_descriptor_tables(struct kvm_vm *vm)
 	extern void *idt_handlers;
 	int i;
 
-	vm->idt = vm_vaddr_alloc_page(vm);
-	vm->handlers = vm_vaddr_alloc_page(vm);
+	vm->idt = __vm_vaddr_alloc_page(vm, MEM_REGION_CODE);
+	vm->handlers = __vm_vaddr_alloc_page(vm, MEM_REGION_CODE);
 	/* Handlers have the same address in both address spaces.*/
 	for (i = 0; i < NUM_INTERRUPTS; i++)
 		set_idt_entry(vm, i, (unsigned long)(&idt_handlers)[i], 0,
-- 
2.37.2.789.g6183377224-goog

[PATCH v6 09/13] KVM: selftests: aarch64: Add aarch64/page_fault_test

[Ricardo Koller]

Add a new test for stage 2 faults when using different combinations of
guest accesses (e.g., write, S1PTW), backing source type (e.g., anon)
and types of faults (e.g., read on hugetlbfs with a hole). The next
commits will add different handling methods and more faults (e.g., uffd
and dirty logging). This first commit starts by adding two sanity checks
for all types of accesses: AF setting by the hw, and accessing memslots
with holes.

Signed-off-by: Ricardo Koller <ricarkol@google.com>
---
 tools/testing/selftests/kvm/Makefile          |   1 +
 .../selftests/kvm/aarch64/page_fault_test.c   | 622 ++++++++++++++++++
 .../selftests/kvm/include/aarch64/processor.h |   8 +
 3 files changed, 631 insertions(+)
 create mode 100644 tools/testing/selftests/kvm/aarch64/page_fault_test.c

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 1bb471aeb103..850e317b9e82 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -149,6 +149,7 @@ TEST_GEN_PROGS_aarch64 += aarch64/arch_timer
 TEST_GEN_PROGS_aarch64 += aarch64/debug-exceptions
 TEST_GEN_PROGS_aarch64 += aarch64/get-reg-list
 TEST_GEN_PROGS_aarch64 += aarch64/hypercalls
+TEST_GEN_PROGS_aarch64 += aarch64/page_fault_test
 TEST_GEN_PROGS_aarch64 += aarch64/psci_test
 TEST_GEN_PROGS_aarch64 += aarch64/vcpu_width_config
 TEST_GEN_PROGS_aarch64 += aarch64/vgic_init
diff --git a/tools/testing/selftests/kvm/aarch64/page_fault_test.c b/tools/testing/selftests/kvm/aarch64/page_fault_test.c
new file mode 100644
index 000000000000..1c7e02003753
--- /dev/null
+++ b/tools/testing/selftests/kvm/aarch64/page_fault_test.c
@@ -0,0 +1,622 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * page_fault_test.c - Test stage 2 faults.
+ *
+ * This test tries different combinations of guest accesses (e.g., write,
+ * S1PTW), backing source type (e.g., anon) and types of faults (e.g., read on
+ * 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>
+#include <kvm_util.h>
+#include <processor.h>
+#include <asm/sysreg.h>
+#include <linux/bitfield.h>
+#include "guest_modes.h"
+#include "userfaultfd_util.h"
+
+/* Guest virtual addresses that point to the test page and its PTE. */
+#define TEST_GVA				0xc0000000
+#define TEST_EXEC_GVA				0xc0000008
+#define TEST_PTE_GVA				0xb0000000
+#define TEST_DATA				0x0123456789ABCDEF
+
+static uint64_t *guest_test_memory = (uint64_t *)TEST_GVA;
+
+#define CMD_NONE				(0)
+#define CMD_SKIP_TEST				(1ULL << 1)
+#define CMD_HOLE_PT				(1ULL << 2)
+#define CMD_HOLE_DATA				(1ULL << 3)
+
+#define PREPARE_FN_NR				10
+#define CHECK_FN_NR				10
+
+struct test_desc {
+	const char *name;
+	uint64_t mem_mark_cmd;
+	/* Skip the test if any prepare function returns false */
+	bool (*guest_prepare[PREPARE_FN_NR])(void);
+	void (*guest_test)(void);
+	void (*guest_test_check[CHECK_FN_NR])(void);
+	void (*dabt_handler)(struct ex_regs *regs);
+	void (*iabt_handler)(struct ex_regs *regs);
+	uint32_t pt_memslot_flags;
+	uint32_t data_memslot_flags;
+	bool skip;
+};
+
+struct test_params {
+	enum vm_mem_backing_src_type src_type;
+	struct test_desc *test_desc;
+};
+
+static inline void flush_tlb_page(uint64_t vaddr)
+{
+	uint64_t page = vaddr >> 12;
+
+	dsb(ishst);
+	asm volatile("tlbi vaae1is, %0" :: "r" (page));
+	dsb(ish);
+	isb();
+}
+
+static void guest_write64(void)
+{
+	uint64_t val;
+
+	WRITE_ONCE(*guest_test_memory, TEST_DATA);
+	val = READ_ONCE(*guest_test_memory);
+	GUEST_ASSERT_EQ(val, TEST_DATA);
+}
+
+/* Check the system for atomic instructions. */
+static bool guest_check_lse(void)
+{
+	uint64_t isar0 = read_sysreg(id_aa64isar0_el1);
+	uint64_t atomic;
+
+	atomic = FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR0_ATOMICS), isar0);
+	return atomic >= 2;
+}
+
+static bool guest_check_dc_zva(void)
+{
+	uint64_t dczid = read_sysreg(dczid_el0);
+	uint64_t dzp = FIELD_GET(ARM64_FEATURE_MASK(DCZID_DZP), dczid);
+
+	return dzp == 0;
+}
+
+/* Compare and swap instruction. */
+static void guest_cas(void)
+{
+	uint64_t val;
+
+	GUEST_ASSERT(guest_check_lse());
+	asm volatile(".arch_extension lse\n"
+		     "casal %0, %1, [%2]\n"
+			:: "r" (0), "r" (TEST_DATA), "r" (guest_test_memory));
+	val = READ_ONCE(*guest_test_memory);
+	GUEST_ASSERT_EQ(val, TEST_DATA);
+}
+
+static void guest_read64(void)
+{
+	uint64_t val;
+
+	val = READ_ONCE(*guest_test_memory);
+	GUEST_ASSERT_EQ(val, 0);
+}
+
+/* Address translation instruction */
+static void guest_at(void)
+{
+	uint64_t par;
+
+	asm volatile("at s1e1r, %0" :: "r" (guest_test_memory));
+	par = read_sysreg(par_el1);
+	isb();
+
+	/* Bit 1 indicates whether the AT was successful */
+	GUEST_ASSERT_EQ(par & 1, 0);
+}
+
+/*
+ * The size of the block written by "dc zva" is guaranteed to be between (2 <<
+ * 0) and (2 << 9), which is safe in our case as we need the write to happen
+ * for at least a word, and not more than a page.
+ */
+static void guest_dc_zva(void)
+{
+	uint16_t val;
+
+	asm volatile("dc zva, %0" :: "r" (guest_test_memory));
+	dsb(ish);
+	val = READ_ONCE(*guest_test_memory);
+	GUEST_ASSERT_EQ(val, 0);
+}
+
+/*
+ * Pre-indexing loads and stores don't have a valid syndrome (ESR_EL2.ISV==0).
+ * And that's special because KVM must take special care with those: they
+ * should still count as accesses for dirty logging or user-faulting, but
+ * should be handled differently on mmio.
+ */
+static void guest_ld_preidx(void)
+{
+	uint64_t val;
+	uint64_t addr = TEST_GVA - 8;
+
+	/*
+	 * This ends up accessing "TEST_GVA + 8 - 8", where "TEST_GVA - 8" is
+	 * in a gap between memslots not backing by anything.
+	 */
+	asm volatile("ldr %0, [%1, #8]!"
+			: "=r" (val), "+r" (addr));
+	GUEST_ASSERT_EQ(val, 0);
+	GUEST_ASSERT_EQ(addr, TEST_GVA);
+}
+
+static void guest_st_preidx(void)
+{
+	uint64_t val = TEST_DATA;
+	uint64_t addr = TEST_GVA - 8;
+
+	asm volatile("str %0, [%1, #8]!"
+			: "+r" (val), "+r" (addr));
+
+	GUEST_ASSERT_EQ(addr, TEST_GVA);
+	val = READ_ONCE(*guest_test_memory);
+}
+
+static bool guest_set_ha(void)
+{
+	uint64_t mmfr1 = read_sysreg(id_aa64mmfr1_el1);
+	uint64_t hadbs, tcr;
+
+	/* Skip if HA is not supported. */
+	hadbs = FIELD_GET(ARM64_FEATURE_MASK(ID_AA64MMFR1_HADBS), mmfr1);
+	if (hadbs == 0)
+		return false;
+
+	tcr = read_sysreg(tcr_el1) | TCR_EL1_HA;
+	write_sysreg(tcr, tcr_el1);
+	isb();
+
+	return true;
+}
+
+static bool guest_clear_pte_af(void)
+{
+	*((uint64_t *)TEST_PTE_GVA) &= ~PTE_AF;
+	flush_tlb_page(TEST_GVA);
+
+	return true;
+}
+
+static void guest_check_pte_af(void)
+{
+	dsb(ish);
+	GUEST_ASSERT_EQ(*((uint64_t *)TEST_PTE_GVA) & PTE_AF, PTE_AF);
+}
+
+static void guest_exec(void)
+{
+	int (*code)(void) = (int (*)(void))TEST_EXEC_GVA;
+	int ret;
+
+	ret = code();
+	GUEST_ASSERT_EQ(ret, 0x77);
+}
+
+static bool guest_prepare(struct test_desc *test)
+{
+	bool (*prepare_fn)(void);
+	int i;
+
+	for (i = 0; i < PREPARE_FN_NR; i++) {
+		prepare_fn = test->guest_prepare[i];
+		if (prepare_fn && !prepare_fn())
+			return false;
+	}
+
+	return true;
+}
+
+static void guest_test_check(struct test_desc *test)
+{
+	void (*check_fn)(void);
+	int i;
+
+	for (i = 0; i < CHECK_FN_NR; i++) {
+		check_fn = test->guest_test_check[i];
+		if (check_fn)
+			check_fn();
+	}
+}
+
+static void guest_code(struct test_desc *test)
+{
+	if (!guest_prepare(test))
+		GUEST_SYNC(CMD_SKIP_TEST);
+
+	GUEST_SYNC(test->mem_mark_cmd);
+
+	if (test->guest_test)
+		test->guest_test();
+
+	guest_test_check(test);
+	GUEST_DONE();
+}
+
+static void no_dabt_handler(struct ex_regs *regs)
+{
+	GUEST_ASSERT_1(false, read_sysreg(far_el1));
+}
+
+static void no_iabt_handler(struct ex_regs *regs)
+{
+	GUEST_ASSERT_1(false, regs->pc);
+}
+
+/* Returns true to continue the test, and false if it should be skipped. */
+static bool punch_hole_in_memslot(struct kvm_vm *vm,
+				  struct userspace_mem_region *region)
+{
+	void *hva = (void *)region->region.userspace_addr;
+	uint64_t paging_size = region->region.memory_size;
+	int ret, fd = region->fd;
+
+	if (fd != -1) {
+		ret = fallocate(fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
+				0, paging_size);
+		TEST_ASSERT(ret == 0, "fallocate failed, errno: %d\n", errno);
+	} else {
+		if (is_backing_src_hugetlb(region->backing_src_type))
+			return false;
+
+		ret = madvise(hva, paging_size, MADV_DONTNEED);
+		TEST_ASSERT(ret == 0, "madvise failed, errno: %d\n", errno);
+	}
+
+	return true;
+}
+
+/* Returns true to continue the test, and false if it should be skipped. */
+static bool handle_cmd(struct kvm_vm *vm, int cmd)
+{
+	struct userspace_mem_region *data_region, *pt_region;
+	bool continue_test = true;
+
+	data_region = vm_get_mem_region(vm, MEM_REGION_DATA);
+	pt_region = vm_get_mem_region(vm, MEM_REGION_PT);
+
+	if (cmd == CMD_SKIP_TEST)
+		continue_test = false;
+
+	if (cmd & CMD_HOLE_PT)
+		continue_test = punch_hole_in_memslot(vm, pt_region);
+	if (cmd & CMD_HOLE_DATA)
+		continue_test = punch_hole_in_memslot(vm, data_region);
+
+	return continue_test;
+}
+
+extern unsigned char __exec_test;
+
+void noinline __return_0x77(void)
+{
+	asm volatile("__exec_test: mov x0, #0x77\n"
+			"ret\n");
+}
+
+/*
+ * Note that this function runs on the host before the test VM starts: there's
+ * no need to sync the D$ and I$ caches.
+ */
+static void load_exec_code_for_test(struct kvm_vm *vm)
+{
+	uint64_t *code, *c;
+	struct userspace_mem_region *region;
+	void *hva;
+
+	region = vm_get_mem_region(vm, MEM_REGION_DATA);
+	hva = (void *)region->region.userspace_addr;
+
+	assert(TEST_EXEC_GVA - TEST_GVA);
+	code = hva + 8;
+
+	/*
+	 * We need the cast to be separate in order for the compiler to not
+	 * complain with: "‘memcpy’ forming offset [1, 7] is out of the bounds
+	 * [0, 1] of object ‘__exec_test’ with type ‘unsigned char’"
+	 */
+	c = (uint64_t *)&__exec_test;
+	memcpy(code, c, 8);
+}
+
+static void setup_abort_handlers(struct kvm_vm *vm, struct kvm_vcpu *vcpu,
+		struct test_desc *test)
+{
+	vm_init_descriptor_tables(vm);
+	vcpu_init_descriptor_tables(vcpu);
+
+	vm_install_sync_handler(vm, VECTOR_SYNC_CURRENT,
+			ESR_EC_DABT, no_dabt_handler);
+	vm_install_sync_handler(vm, VECTOR_SYNC_CURRENT,
+			ESR_EC_IABT, no_iabt_handler);
+}
+
+static void setup_gva_maps(struct kvm_vm *vm)
+{
+	struct userspace_mem_region *region;
+	uint64_t pte_gpa;
+
+	region = vm_get_mem_region(vm, MEM_REGION_DATA);
+	/* Map TEST_GVA first. This will install a new PTE. */
+	virt_pg_map(vm, TEST_GVA, region->region.guest_phys_addr);
+	/* Then map TEST_PTE_GVA to the above PTE. */
+	pte_gpa = addr_hva2gpa(vm, virt_get_pte_hva(vm, TEST_GVA));
+	virt_pg_map(vm, TEST_PTE_GVA, pte_gpa);
+}
+
+unsigned long get_max_gfn(enum vm_guest_mode mode)
+{
+	unsigned int pa_bits = vm_guest_mode_params[mode].pa_bits;
+	unsigned int page_shift = vm_guest_mode_params[mode].page_shift;
+
+	return ((1ULL << pa_bits) >> page_shift) - 1;
+}
+
+/* Create a code memslot at pfn=0, and data and PT ones at max_gfn. */
+static struct kvm_vm_mem_params setup_memslots(enum vm_guest_mode mode,
+					       struct test_params *p)
+{
+	uint64_t backing_src_pagesz = get_backing_src_pagesz(p->src_type);
+	uint64_t guest_page_size = vm_guest_mode_params[mode].page_size;
+	uint64_t max_gfn = get_max_gfn(mode);
+	/* Enough for 2M of code when using 4K guest pages. */
+	uint64_t code_npages = 512;
+	uint64_t pt_size, data_size, data_gpa;
+
+	/*
+	 * This test requires 1 pgd, 2 pud, 4 pmd, and 6 pte pages when using
+	 * VM_MODE_P48V48_4K. Note that the .text takes ~1.6MBs.  That's 13
+	 * pages. VM_MODE_P48V48_4K is the mode with most PT pages; let's use
+	 * twice that just in case.
+	 */
+	pt_size = 26 * guest_page_size;
+
+	/* memslot sizes and gpa's must be aligned to the backing page size */
+	pt_size = align_up(pt_size, backing_src_pagesz);
+	data_size = align_up(guest_page_size, backing_src_pagesz);
+	data_gpa = (max_gfn * guest_page_size) - data_size;
+	data_gpa = align_down(data_gpa, backing_src_pagesz);
+
+	struct kvm_vm_mem_params mem_params = {
+		.region[0] = {
+			.src_type = VM_MEM_SRC_ANONYMOUS,
+			.guest_paddr = 0,
+			.slot = 0,
+			.npages = code_npages,
+			.flags = 0,
+			.enabled = true,
+		},
+		.region[1] = {
+			.src_type = p->src_type,
+			.guest_paddr = data_gpa - pt_size,
+			.slot = 1,
+			.npages = pt_size / guest_page_size,
+			.flags = p->test_desc->pt_memslot_flags,
+			.enabled = true,
+		},
+		.region[2] = {
+			.src_type = p->src_type,
+			.guest_paddr = data_gpa,
+			.slot = 2,
+			.npages = data_size / guest_page_size,
+			.flags = p->test_desc->data_memslot_flags,
+			.enabled = true,
+		},
+		.region_idx[MEM_REGION_CODE] = 0,
+		.region_idx[MEM_REGION_PT] = 1,
+		.region_idx[MEM_REGION_DATA] = 2,
+		.mode = mode,
+	};
+
+	return mem_params;
+}
+
+static void print_test_banner(enum vm_guest_mode mode, struct test_params *p)
+{
+	struct test_desc *test = p->test_desc;
+
+	pr_debug("Test: %s\n", test->name);
+	pr_debug("Testing guest mode: %s\n", vm_guest_mode_string(mode));
+	pr_debug("Testing memory backing src type: %s\n",
+			vm_mem_backing_src_alias(p->src_type)->name);
+}
+
+/*
+ * This function either succeeds, skips the test (after setting test->skip), or
+ * fails with a TEST_FAIL that aborts all tests.
+ */
+static void vcpu_run_loop(struct kvm_vm *vm, struct kvm_vcpu *vcpu,
+			  struct test_desc *test)
+{
+	struct ucall uc;
+
+	for (;;) {
+		vcpu_run(vcpu);
+
+		switch (get_ucall(vcpu, &uc)) {
+		case UCALL_SYNC:
+			if (!handle_cmd(vm, uc.args[1])) {
+				test->skip = true;
+				goto done;
+			}
+			break;
+		case UCALL_ABORT:
+			REPORT_GUEST_ASSERT_2(uc, "values: %#lx, %#lx");
+			break;
+		case UCALL_DONE:
+			goto done;
+		default:
+			TEST_FAIL("Unknown ucall %lu", uc.cmd);
+		}
+	}
+
+done:
+	pr_debug(test->skip ? "Skipped.\n" : "Done.\n");
+	return;
+}
+
+static void run_test(enum vm_guest_mode mode, void *arg)
+{
+	struct test_params *p = (struct test_params *)arg;
+	struct test_desc *test = p->test_desc;
+	struct kvm_vm *vm;
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm_mem_params mem_params;
+
+	print_test_banner(mode, p);
+
+	mem_params = setup_memslots(mode, p);
+	vm = ____vm_create(&mem_params);
+	kvm_vm_elf_load(vm, program_invocation_name);
+	vcpu = vm_vcpu_add(vm, 0, guest_code);
+
+	setup_gva_maps(vm);
+
+	ucall_init(vm, NULL);
+
+	load_exec_code_for_test(vm);
+	setup_abort_handlers(vm, vcpu, test);
+	vcpu_args_set(vcpu, 1, test);
+
+	vcpu_run_loop(vm, vcpu, test);
+
+	ucall_uninit(vm);
+	kvm_vm_free(vm);
+}
+
+static void help(char *name)
+{
+	puts("");
+	printf("usage: %s [-h] [-s mem-type]\n", name);
+	puts("");
+	guest_modes_help();
+	backing_src_help("-s");
+	puts("");
+}
+
+#define SNAME(s)			#s
+#define SCAT2(a, b)			SNAME(a ## _ ## b)
+#define SCAT3(a, b, c)			SCAT2(a, SCAT2(b, c))
+
+#define _CHECK(_test)			_CHECK_##_test
+#define _PREPARE(_test)			_PREPARE_##_test
+#define _PREPARE_guest_read64		NULL
+#define _PREPARE_guest_ld_preidx	NULL
+#define _PREPARE_guest_write64		NULL
+#define _PREPARE_guest_st_preidx	NULL
+#define _PREPARE_guest_exec		NULL
+#define _PREPARE_guest_at		NULL
+#define _PREPARE_guest_dc_zva		guest_check_dc_zva
+#define _PREPARE_guest_cas		guest_check_lse
+
+/* With or without access flag checks */
+#define _PREPARE_with_af		guest_set_ha, guest_clear_pte_af
+#define _PREPARE_no_af			NULL
+#define _CHECK_with_af			guest_check_pte_af
+#define _CHECK_no_af			NULL
+
+/* Performs an access and checks that no faults were triggered. */
+#define TEST_ACCESS(_access, _with_af, _mark_cmd)				\
+{										\
+	.name			= SCAT3(_access, _with_af, #_mark_cmd),		\
+	.guest_prepare		= { _PREPARE(_with_af),				\
+				    _PREPARE(_access) },			\
+	.mem_mark_cmd		= _mark_cmd,					\
+	.guest_test		= _access,					\
+	.guest_test_check	= { _CHECK(_with_af) },				\
+}
+
+static struct test_desc tests[] = {
+
+	/* Check that HW is setting the Access Flag (AF) (sanity checks). */
+	TEST_ACCESS(guest_read64, with_af, CMD_NONE),
+	TEST_ACCESS(guest_ld_preidx, with_af, CMD_NONE),
+	TEST_ACCESS(guest_cas, with_af, CMD_NONE),
+	TEST_ACCESS(guest_write64, with_af, CMD_NONE),
+	TEST_ACCESS(guest_st_preidx, with_af, CMD_NONE),
+	TEST_ACCESS(guest_dc_zva, with_af, CMD_NONE),
+	TEST_ACCESS(guest_exec, with_af, CMD_NONE),
+
+	/*
+	 * Accessing a hole in the data memslot (punched with fallocate or
+	 * madvise) shouldn't fault (more sanity checks).
+	 */
+	TEST_ACCESS(guest_read64, no_af, CMD_HOLE_DATA),
+	TEST_ACCESS(guest_cas, no_af, CMD_HOLE_DATA),
+	TEST_ACCESS(guest_ld_preidx, no_af, CMD_HOLE_DATA),
+	TEST_ACCESS(guest_write64, no_af, CMD_HOLE_DATA),
+	TEST_ACCESS(guest_st_preidx, no_af, CMD_HOLE_DATA),
+	TEST_ACCESS(guest_at, no_af, CMD_HOLE_DATA),
+	TEST_ACCESS(guest_dc_zva, no_af, CMD_HOLE_DATA),
+
+	{ 0 }
+};
+
+static void for_each_test_and_guest_mode(
+		void (*func)(enum vm_guest_mode m, void *a),
+		enum vm_mem_backing_src_type src_type)
+{
+	struct test_desc *t;
+
+	for (t = &tests[0]; t->name; t++) {
+		if (t->skip)
+			continue;
+
+		struct test_params p = {
+			.src_type = src_type,
+			.test_desc = t,
+		};
+
+		for_each_guest_mode(run_test, &p);
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	enum vm_mem_backing_src_type src_type;
+	int opt;
+
+	setbuf(stdout, NULL);
+
+	src_type = DEFAULT_VM_MEM_SRC;
+
+	guest_modes_append_default();
+
+	while ((opt = getopt(argc, argv, "hm:s:")) != -1) {
+		switch (opt) {
+		case 'm':
+			guest_modes_cmdline(optarg);
+			break;
+		case 's':
+			src_type = parse_backing_src_type(optarg);
+			break;
+		case 'h':
+		default:
+			help(argv[0]);
+			exit(0);
+		}
+	}
+
+	for_each_test_and_guest_mode(run_test, src_type);
+	return 0;
+}
diff --git a/tools/testing/selftests/kvm/include/aarch64/processor.h b/tools/testing/selftests/kvm/include/aarch64/processor.h
index c1ddca8db225..5f977528e09c 100644
--- a/tools/testing/selftests/kvm/include/aarch64/processor.h
+++ b/tools/testing/selftests/kvm/include/aarch64/processor.h
@@ -105,11 +105,19 @@ enum {
 #define ESR_EC_MASK		(ESR_EC_NUM - 1)
 
 #define ESR_EC_SVC64		0x15
+#define ESR_EC_IABT		0x21
+#define ESR_EC_DABT		0x25
 #define ESR_EC_HW_BP_CURRENT	0x31
 #define ESR_EC_SSTEP_CURRENT	0x33
 #define ESR_EC_WP_CURRENT	0x35
 #define ESR_EC_BRK_INS		0x3c
 
+/* Access flag */
+#define PTE_AF			(1ULL << 10)
+
+/* Access flag update enable/disable */
+#define TCR_EL1_HA		(1ULL << 39)
+
 void aarch64_get_supported_page_sizes(uint32_t ipa,
 				      bool *ps4k, bool *ps16k, bool *ps64k);
 
-- 
2.37.2.789.g6183377224-goog

[PATCH v6 10/13] KVM: selftests: aarch64: Add userfaultfd tests into page_fault_test

[Ricardo Koller]

Add some userfaultfd tests into page_fault_test. Punch holes into the
data and/or page-table memslots, perform some accesses, and check that
the faults are taken (or not taken) when expected.

Signed-off-by: Ricardo Koller <ricarkol@google.com>
---
 .../selftests/kvm/aarch64/page_fault_test.c   | 190 +++++++++++++++++-
 1 file changed, 188 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/kvm/aarch64/page_fault_test.c b/tools/testing/selftests/kvm/aarch64/page_fault_test.c
index 1c7e02003753..57466d213b95 100644
--- a/tools/testing/selftests/kvm/aarch64/page_fault_test.c
+++ b/tools/testing/selftests/kvm/aarch64/page_fault_test.c
@@ -35,6 +35,12 @@ static uint64_t *guest_test_memory = (uint64_t *)TEST_GVA;
 #define PREPARE_FN_NR				10
 #define CHECK_FN_NR				10
 
+static struct event_cnt {
+	int uffd_faults;
+	/* uffd_faults is incremented from multiple threads. */
+	pthread_mutex_t uffd_faults_mutex;
+} events;
+
 struct test_desc {
 	const char *name;
 	uint64_t mem_mark_cmd;
@@ -42,11 +48,14 @@ struct test_desc {
 	bool (*guest_prepare[PREPARE_FN_NR])(void);
 	void (*guest_test)(void);
 	void (*guest_test_check[CHECK_FN_NR])(void);
+	uffd_handler_t uffd_pt_handler;
+	uffd_handler_t uffd_data_handler;
 	void (*dabt_handler)(struct ex_regs *regs);
 	void (*iabt_handler)(struct ex_regs *regs);
 	uint32_t pt_memslot_flags;
 	uint32_t data_memslot_flags;
 	bool skip;
+	struct event_cnt expected_events;
 };
 
 struct test_params {
@@ -263,7 +272,110 @@ static void no_iabt_handler(struct ex_regs *regs)
 	GUEST_ASSERT_1(false, regs->pc);
 }
 
+static struct uffd_args {
+	char *copy;
+	void *hva;
+	uint64_t paging_size;
+} pt_args, data_args;
+
 /* Returns true to continue the test, and false if it should be skipped. */
+static int uffd_generic_handler(int uffd_mode, int uffd,
+		struct uffd_msg *msg, struct uffd_args *args,
+		bool expect_write)
+{
+	uint64_t addr = msg->arg.pagefault.address;
+	uint64_t flags = msg->arg.pagefault.flags;
+	struct uffdio_copy copy;
+	int ret;
+
+	TEST_ASSERT(uffd_mode == UFFDIO_REGISTER_MODE_MISSING,
+			"The only expected UFFD mode is MISSING");
+	ASSERT_EQ(!!(flags & UFFD_PAGEFAULT_FLAG_WRITE), expect_write);
+	ASSERT_EQ(addr, (uint64_t)args->hva);
+
+	pr_debug("uffd fault: addr=%p write=%d\n",
+			(void *)addr, !!(flags & UFFD_PAGEFAULT_FLAG_WRITE));
+
+	copy.src = (uint64_t)args->copy;
+	copy.dst = addr;
+	copy.len = args->paging_size;
+	copy.mode = 0;
+
+	ret = ioctl(uffd, UFFDIO_COPY, &copy);
+	if (ret == -1) {
+		pr_info("Failed UFFDIO_COPY in 0x%lx with errno: %d\n",
+				addr, errno);
+		return ret;
+	}
+
+	pthread_mutex_lock(&events.uffd_faults_mutex);
+	events.uffd_faults += 1;
+	pthread_mutex_unlock(&events.uffd_faults_mutex);
+	return 0;
+}
+
+static int uffd_pt_write_handler(int mode, int uffd, struct uffd_msg *msg)
+{
+	return uffd_generic_handler(mode, uffd, msg, &pt_args, true);
+}
+
+static int uffd_data_write_handler(int mode, int uffd, struct uffd_msg *msg)
+{
+	return uffd_generic_handler(mode, uffd, msg, &data_args, true);
+}
+
+static int uffd_data_read_handler(int mode, int uffd, struct uffd_msg *msg)
+{
+	return uffd_generic_handler(mode, uffd, msg, &data_args, false);
+}
+
+static void setup_uffd_args(struct userspace_mem_region *region,
+				struct uffd_args *args)
+{
+	args->hva = (void *)region->region.userspace_addr;
+	args->paging_size = region->region.memory_size;
+
+	args->copy = malloc(args->paging_size);
+	TEST_ASSERT(args->copy, "Failed to allocate data copy.");
+	memcpy(args->copy, args->hva, args->paging_size);
+}
+
+static void setup_uffd(struct kvm_vm *vm, struct test_params *p,
+		struct uffd_desc **pt_uffd, struct uffd_desc **data_uffd)
+{
+	struct test_desc *test = p->test_desc;
+
+	setup_uffd_args(vm_get_mem_region(vm, MEM_REGION_PT), &pt_args);
+	setup_uffd_args(vm_get_mem_region(vm, MEM_REGION_DATA), &data_args);
+
+	*pt_uffd = NULL;
+	if (test->uffd_pt_handler)
+		*pt_uffd = uffd_setup_demand_paging(
+				UFFDIO_REGISTER_MODE_MISSING, 0,
+				pt_args.hva, pt_args.paging_size,
+				test->uffd_pt_handler);
+
+	*data_uffd = NULL;
+	if (test->uffd_data_handler)
+		*data_uffd = uffd_setup_demand_paging(
+				UFFDIO_REGISTER_MODE_MISSING, 0,
+				data_args.hva, data_args.paging_size,
+				test->uffd_data_handler);
+}
+
+static void free_uffd(struct test_desc *test, struct uffd_desc *pt_uffd,
+			struct uffd_desc *data_uffd)
+{
+	if (test->uffd_pt_handler)
+		uffd_stop_demand_paging(pt_uffd);
+	if (test->uffd_data_handler)
+		uffd_stop_demand_paging(data_uffd);
+
+	free(pt_args.copy);
+	free(data_args.copy);
+}
+
+/* Returns false if the test should be skipped. */
 static bool punch_hole_in_memslot(struct kvm_vm *vm,
 				  struct userspace_mem_region *region)
 {
@@ -431,6 +543,11 @@ static struct kvm_vm_mem_params setup_memslots(enum vm_guest_mode mode,
 	return mem_params;
 }
 
+static void check_event_counts(struct test_desc *test)
+{
+	ASSERT_EQ(test->expected_events.uffd_faults, events.uffd_faults);
+}
+
 static void print_test_banner(enum vm_guest_mode mode, struct test_params *p)
 {
 	struct test_desc *test = p->test_desc;
@@ -441,12 +558,17 @@ static void print_test_banner(enum vm_guest_mode mode, struct test_params *p)
 			vm_mem_backing_src_alias(p->src_type)->name);
 }
 
+static void reset_event_counts(void)
+{
+	memset(&events, 0, sizeof(events));
+}
+
 /*
  * This function either succeeds, skips the test (after setting test->skip), or
  * fails with a TEST_FAIL that aborts all tests.
  */
 static void vcpu_run_loop(struct kvm_vm *vm, struct kvm_vcpu *vcpu,
-			  struct test_desc *test)
+		struct test_desc *test)
 {
 	struct ucall uc;
 
@@ -481,6 +603,7 @@ static void run_test(enum vm_guest_mode mode, void *arg)
 	struct test_desc *test = p->test_desc;
 	struct kvm_vm *vm;
 	struct kvm_vcpu *vcpu;
+	struct uffd_desc *pt_uffd, *data_uffd;
 	struct kvm_vm_mem_params mem_params;
 
 	print_test_banner(mode, p);
@@ -494,7 +617,16 @@ static void run_test(enum vm_guest_mode mode, void *arg)
 
 	ucall_init(vm, NULL);
 
+	reset_event_counts();
+
+	/*
+	 * Set some code in the data memslot for the guest to execute (only
+	 * applicable to the EXEC tests). This has to be done before
+	 * setup_uffd() as that function copies the memslot data for the uffd
+	 * handler.
+	 */
 	load_exec_code_for_test(vm);
+	setup_uffd(vm, p, &pt_uffd, &data_uffd);
 	setup_abort_handlers(vm, vcpu, test);
 	vcpu_args_set(vcpu, 1, test);
 
@@ -502,6 +634,14 @@ static void run_test(enum vm_guest_mode mode, void *arg)
 
 	ucall_uninit(vm);
 	kvm_vm_free(vm);
+	free_uffd(test, pt_uffd, data_uffd);
+
+	/*
+	 * Make sure we check the events after the uffd threads have exited,
+	 * which means they updated their respective event counters.
+	 */
+	if (!test->skip)
+		check_event_counts(test);
 }
 
 static void help(char *name)
@@ -517,6 +657,7 @@ static void help(char *name)
 #define SNAME(s)			#s
 #define SCAT2(a, b)			SNAME(a ## _ ## b)
 #define SCAT3(a, b, c)			SCAT2(a, SCAT2(b, c))
+#define SCAT4(a, b, c, d)		SCAT2(a, SCAT3(b, c, d))
 
 #define _CHECK(_test)			_CHECK_##_test
 #define _PREPARE(_test)			_PREPARE_##_test
@@ -535,7 +676,7 @@ static void help(char *name)
 #define _CHECK_with_af			guest_check_pte_af
 #define _CHECK_no_af			NULL
 
-/* Performs an access and checks that no faults were triggered. */
+/* Performs an access and checks that no faults (no events) were triggered. */
 #define TEST_ACCESS(_access, _with_af, _mark_cmd)				\
 {										\
 	.name			= SCAT3(_access, _with_af, #_mark_cmd),		\
@@ -544,6 +685,21 @@ static void help(char *name)
 	.mem_mark_cmd		= _mark_cmd,					\
 	.guest_test		= _access,					\
 	.guest_test_check	= { _CHECK(_with_af) },				\
+	.expected_events	= { 0 },					\
+}
+
+#define TEST_UFFD(_access, _with_af, _mark_cmd,					\
+		  _uffd_data_handler, _uffd_pt_handler, _uffd_faults)		\
+{										\
+	.name			= SCAT4(uffd, _access, _with_af, #_mark_cmd),	\
+	.guest_prepare		= { _PREPARE(_with_af),				\
+				    _PREPARE(_access) },			\
+	.guest_test		= _access,					\
+	.mem_mark_cmd		= _mark_cmd,					\
+	.guest_test_check	= { _CHECK(_with_af) },				\
+	.uffd_data_handler	= _uffd_data_handler,				\
+	.uffd_pt_handler	= _uffd_pt_handler,				\
+	.expected_events	= { .uffd_faults = _uffd_faults, },		\
 }
 
 static struct test_desc tests[] = {
@@ -569,6 +725,36 @@ static struct test_desc tests[] = {
 	TEST_ACCESS(guest_at, no_af, CMD_HOLE_DATA),
 	TEST_ACCESS(guest_dc_zva, no_af, CMD_HOLE_DATA),
 
+	/*
+	 * Punch holes in the test and PT memslots and mark them for
+	 * userfaultfd handling. This should result in 2 faults: the test
+	 * access and its respective S1 page table walk (S1PTW).
+	 */
+	TEST_UFFD(guest_read64, with_af, CMD_HOLE_DATA | CMD_HOLE_PT,
+			uffd_data_read_handler, uffd_pt_write_handler, 2),
+	/* no_af should also lead to a PT write. */
+	TEST_UFFD(guest_read64, no_af, CMD_HOLE_DATA | CMD_HOLE_PT,
+			uffd_data_read_handler, uffd_pt_write_handler, 2),
+	/* Note how that cas invokes the read handler. */
+	TEST_UFFD(guest_cas, with_af, CMD_HOLE_DATA | CMD_HOLE_PT,
+			uffd_data_read_handler, uffd_pt_write_handler, 2),
+	/*
+	 * Can't test guest_at with_af as it's IMPDEF whether the AF is set.
+	 * The S1PTW fault should still be marked as a write.
+	 */
+	TEST_UFFD(guest_at, no_af, CMD_HOLE_DATA | CMD_HOLE_PT,
+			uffd_data_read_handler, uffd_pt_write_handler, 1),
+	TEST_UFFD(guest_ld_preidx, with_af, CMD_HOLE_DATA | CMD_HOLE_PT,
+			uffd_data_read_handler, uffd_pt_write_handler, 2),
+	TEST_UFFD(guest_write64, with_af, CMD_HOLE_DATA | CMD_HOLE_PT,
+			uffd_data_write_handler, uffd_pt_write_handler, 2),
+	TEST_UFFD(guest_dc_zva, with_af, CMD_HOLE_DATA | CMD_HOLE_PT,
+			uffd_data_write_handler, uffd_pt_write_handler, 2),
+	TEST_UFFD(guest_st_preidx, with_af, CMD_HOLE_DATA | CMD_HOLE_PT,
+			uffd_data_write_handler, uffd_pt_write_handler, 2),
+	TEST_UFFD(guest_exec, with_af, CMD_HOLE_DATA | CMD_HOLE_PT,
+			uffd_data_read_handler, uffd_pt_write_handler, 2),
+
 	{ 0 }
 };
 
-- 
2.37.2.789.g6183377224-goog

[PATCH v6 11/13] KVM: selftests: aarch64: Add dirty logging tests into page_fault_test

[Ricardo Koller]

Add some dirty logging tests into page_fault_test. Mark the data and/or
page-table memslots for dirty logging, perform some accesses, and check
that the dirty log bits are set or clean when expected.

Signed-off-by: Ricardo Koller <ricarkol@google.com>
---
 .../selftests/kvm/aarch64/page_fault_test.c   | 75 +++++++++++++++++++
 1 file changed, 75 insertions(+)

diff --git a/tools/testing/selftests/kvm/aarch64/page_fault_test.c b/tools/testing/selftests/kvm/aarch64/page_fault_test.c
index 57466d213b95..481c96eec34a 100644
--- a/tools/testing/selftests/kvm/aarch64/page_fault_test.c
+++ b/tools/testing/selftests/kvm/aarch64/page_fault_test.c
@@ -31,6 +31,11 @@ static uint64_t *guest_test_memory = (uint64_t *)TEST_GVA;
 #define CMD_SKIP_TEST				(1ULL << 1)
 #define CMD_HOLE_PT				(1ULL << 2)
 #define CMD_HOLE_DATA				(1ULL << 3)
+#define CMD_CHECK_WRITE_IN_DIRTY_LOG		(1ULL << 4)
+#define CMD_CHECK_S1PTW_WR_IN_DIRTY_LOG		(1ULL << 5)
+#define CMD_CHECK_NO_WRITE_IN_DIRTY_LOG		(1ULL << 6)
+#define CMD_CHECK_NO_S1PTW_WR_IN_DIRTY_LOG	(1ULL << 7)
+#define CMD_SET_PTE_AF				(1ULL << 8)
 
 #define PREPARE_FN_NR				10
 #define CHECK_FN_NR				10
@@ -213,6 +218,21 @@ static void guest_check_pte_af(void)
 	GUEST_ASSERT_EQ(*((uint64_t *)TEST_PTE_GVA) & PTE_AF, PTE_AF);
 }
 
+static void guest_check_write_in_dirty_log(void)
+{
+	GUEST_SYNC(CMD_CHECK_WRITE_IN_DIRTY_LOG);
+}
+
+static void guest_check_no_write_in_dirty_log(void)
+{
+	GUEST_SYNC(CMD_CHECK_NO_WRITE_IN_DIRTY_LOG);
+}
+
+static void guest_check_s1ptw_wr_in_dirty_log(void)
+{
+	GUEST_SYNC(CMD_CHECK_S1PTW_WR_IN_DIRTY_LOG);
+}
+
 static void guest_exec(void)
 {
 	int (*code)(void) = (int (*)(void))TEST_EXEC_GVA;
@@ -398,6 +418,21 @@ static bool punch_hole_in_memslot(struct kvm_vm *vm,
 	return true;
 }
 
+static bool check_write_in_dirty_log(struct kvm_vm *vm,
+		struct userspace_mem_region *region, uint64_t host_pg_nr)
+{
+	unsigned long *bmap;
+	bool first_page_dirty;
+	uint64_t size = region->region.memory_size;
+
+	/* getpage_size() is not always equal to vm->page_size */
+	bmap = bitmap_zalloc(size / getpagesize());
+	kvm_vm_get_dirty_log(vm, region->region.slot, bmap);
+	first_page_dirty = test_bit(host_pg_nr, bmap);
+	free(bmap);
+	return first_page_dirty;
+}
+
 /* Returns true to continue the test, and false if it should be skipped. */
 static bool handle_cmd(struct kvm_vm *vm, int cmd)
 {
@@ -414,6 +449,18 @@ static bool handle_cmd(struct kvm_vm *vm, int cmd)
 		continue_test = punch_hole_in_memslot(vm, pt_region);
 	if (cmd & CMD_HOLE_DATA)
 		continue_test = punch_hole_in_memslot(vm, data_region);
+	if (cmd & CMD_CHECK_WRITE_IN_DIRTY_LOG)
+		TEST_ASSERT(check_write_in_dirty_log(vm, data_region, 0),
+				"Missing write in dirty log");
+	if (cmd & CMD_CHECK_S1PTW_WR_IN_DIRTY_LOG)
+		TEST_ASSERT(check_write_in_dirty_log(vm, pt_region, 0),
+				"Missing s1ptw write in dirty log");
+	if (cmd & CMD_CHECK_NO_WRITE_IN_DIRTY_LOG)
+		TEST_ASSERT(!check_write_in_dirty_log(vm, data_region, 0),
+				"Unexpected write in dirty log");
+	if (cmd & CMD_CHECK_NO_S1PTW_WR_IN_DIRTY_LOG)
+		TEST_ASSERT(!check_write_in_dirty_log(vm, pt_region, 0),
+				"Unexpected s1ptw write in dirty log");
 
 	return continue_test;
 }
@@ -702,6 +749,19 @@ static void help(char *name)
 	.expected_events	= { .uffd_faults = _uffd_faults, },		\
 }
 
+#define TEST_DIRTY_LOG(_access, _with_af, _test_check)				\
+{										\
+	.name			= SCAT3(dirty_log, _access, _with_af),		\
+	.data_memslot_flags	= KVM_MEM_LOG_DIRTY_PAGES,			\
+	.pt_memslot_flags	= KVM_MEM_LOG_DIRTY_PAGES,			\
+	.guest_prepare		= { _PREPARE(_with_af),				\
+				    _PREPARE(_access) },			\
+	.guest_test		= _access,					\
+	.guest_test_check	= { _CHECK(_with_af), _test_check,		\
+				    guest_check_s1ptw_wr_in_dirty_log},		\
+	.expected_events	= { 0 },					\
+}
+
 static struct test_desc tests[] = {
 
 	/* Check that HW is setting the Access Flag (AF) (sanity checks). */
@@ -755,6 +815,21 @@ static struct test_desc tests[] = {
 	TEST_UFFD(guest_exec, with_af, CMD_HOLE_DATA | CMD_HOLE_PT,
 			uffd_data_read_handler, uffd_pt_write_handler, 2),
 
+	/*
+	 * Try accesses when the data and PT memslots are both tracked for
+	 * dirty logging.
+	 */
+	TEST_DIRTY_LOG(guest_read64, with_af, guest_check_no_write_in_dirty_log),
+	/* no_af should also lead to a PT write. */
+	TEST_DIRTY_LOG(guest_read64, no_af, guest_check_no_write_in_dirty_log),
+	TEST_DIRTY_LOG(guest_ld_preidx, with_af, guest_check_no_write_in_dirty_log),
+	TEST_DIRTY_LOG(guest_at, no_af, guest_check_no_write_in_dirty_log),
+	TEST_DIRTY_LOG(guest_exec, with_af, guest_check_no_write_in_dirty_log),
+	TEST_DIRTY_LOG(guest_write64, with_af, guest_check_write_in_dirty_log),
+	TEST_DIRTY_LOG(guest_cas, with_af, guest_check_write_in_dirty_log),
+	TEST_DIRTY_LOG(guest_dc_zva, with_af, guest_check_write_in_dirty_log),
+	TEST_DIRTY_LOG(guest_st_preidx, with_af, guest_check_write_in_dirty_log),
+
 	{ 0 }
 };
 
-- 
2.37.2.789.g6183377224-goog

[PATCH v6 12/13] KVM: selftests: aarch64: Add readonly memslot tests into page_fault_test

[Ricardo Koller]

Add some readonly memslot tests into page_fault_test. Mark the data
and/or page-table memslots as readonly, perform some accesses, and check
that the right fault is triggered when expected (e.g., a store with no
write-back should lead to an mmio exit).

Signed-off-by: Ricardo Koller <ricarkol@google.com>
---
 .../selftests/kvm/aarch64/page_fault_test.c   | 101 +++++++++++++++++-
 1 file changed, 100 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kvm/aarch64/page_fault_test.c b/tools/testing/selftests/kvm/aarch64/page_fault_test.c
index 481c96eec34a..39fc2103fdd6 100644
--- a/tools/testing/selftests/kvm/aarch64/page_fault_test.c
+++ b/tools/testing/selftests/kvm/aarch64/page_fault_test.c
@@ -41,6 +41,8 @@ static uint64_t *guest_test_memory = (uint64_t *)TEST_GVA;
 #define CHECK_FN_NR				10
 
 static struct event_cnt {
+	int mmio_exits;
+	int fail_vcpu_runs;
 	int uffd_faults;
 	/* uffd_faults is incremented from multiple threads. */
 	pthread_mutex_t uffd_faults_mutex;
@@ -57,6 +59,8 @@ struct test_desc {
 	uffd_handler_t uffd_data_handler;
 	void (*dabt_handler)(struct ex_regs *regs);
 	void (*iabt_handler)(struct ex_regs *regs);
+	void (*mmio_handler)(struct kvm_vm *vm, struct kvm_run *run);
+	void (*fail_vcpu_run_handler)(int ret);
 	uint32_t pt_memslot_flags;
 	uint32_t data_memslot_flags;
 	bool skip;
@@ -418,6 +422,31 @@ static bool punch_hole_in_memslot(struct kvm_vm *vm,
 	return true;
 }
 
+static void mmio_on_test_gpa_handler(struct kvm_vm *vm, struct kvm_run *run)
+{
+	struct userspace_mem_region *region;
+	void *hva;
+
+	region = vm_get_mem_region(vm, MEM_REGION_DATA);
+	hva = (void *)region->region.userspace_addr;
+
+	ASSERT_EQ(run->mmio.phys_addr, region->region.guest_phys_addr);
+
+	memcpy(hva, run->mmio.data, run->mmio.len);
+	events.mmio_exits += 1;
+}
+
+static void mmio_no_handler(struct kvm_vm *vm, struct kvm_run *run)
+{
+	uint64_t data;
+
+	memcpy(&data, run->mmio.data, sizeof(data));
+	pr_debug("addr=%lld len=%d w=%d data=%lx\n",
+			run->mmio.phys_addr, run->mmio.len,
+			run->mmio.is_write, data);
+	TEST_FAIL("There was no MMIO exit expected.");
+}
+
 static bool check_write_in_dirty_log(struct kvm_vm *vm,
 		struct userspace_mem_region *region, uint64_t host_pg_nr)
 {
@@ -465,6 +494,18 @@ static bool handle_cmd(struct kvm_vm *vm, int cmd)
 	return continue_test;
 }
 
+void fail_vcpu_run_no_handler(int ret)
+{
+	TEST_FAIL("Unexpected vcpu run failure\n");
+}
+
+void fail_vcpu_run_mmio_no_syndrome_handler(int ret)
+{
+	TEST_ASSERT(errno == ENOSYS,
+		"The mmio handler should have returned not implemented.");
+	events.fail_vcpu_runs += 1;
+}
+
 extern unsigned char __exec_test;
 
 void noinline __return_0x77(void)
@@ -590,9 +631,20 @@ static struct kvm_vm_mem_params setup_memslots(enum vm_guest_mode mode,
 	return mem_params;
 }
 
+static void setup_default_handlers(struct test_desc *test)
+{
+	if (!test->mmio_handler)
+		test->mmio_handler = mmio_no_handler;
+
+	if (!test->fail_vcpu_run_handler)
+		test->fail_vcpu_run_handler = fail_vcpu_run_no_handler;
+}
+
 static void check_event_counts(struct test_desc *test)
 {
 	ASSERT_EQ(test->expected_events.uffd_faults, events.uffd_faults);
+	ASSERT_EQ(test->expected_events.mmio_exits, events.mmio_exits);
+	ASSERT_EQ(test->expected_events.fail_vcpu_runs, events.fail_vcpu_runs);
 }
 
 static void print_test_banner(enum vm_guest_mode mode, struct test_params *p)
@@ -617,10 +669,18 @@ static void reset_event_counts(void)
 static void vcpu_run_loop(struct kvm_vm *vm, struct kvm_vcpu *vcpu,
 		struct test_desc *test)
 {
+	struct kvm_run *run;
 	struct ucall uc;
+	int ret;
+
+	run = vcpu->run;
 
 	for (;;) {
-		vcpu_run(vcpu);
+		ret = _vcpu_run(vcpu);
+		if (ret) {
+			test->fail_vcpu_run_handler(ret);
+			goto done;
+		}
 
 		switch (get_ucall(vcpu, &uc)) {
 		case UCALL_SYNC:
@@ -634,6 +694,10 @@ static void vcpu_run_loop(struct kvm_vm *vm, struct kvm_vcpu *vcpu,
 			break;
 		case UCALL_DONE:
 			goto done;
+		case UCALL_NONE:
+			if (run->exit_reason == KVM_EXIT_MMIO)
+				test->mmio_handler(vm, run);
+			break;
 		default:
 			TEST_FAIL("Unknown ucall %lu", uc.cmd);
 		}
@@ -675,6 +739,7 @@ static void run_test(enum vm_guest_mode mode, void *arg)
 	load_exec_code_for_test(vm);
 	setup_uffd(vm, p, &pt_uffd, &data_uffd);
 	setup_abort_handlers(vm, vcpu, test);
+	setup_default_handlers(test);
 	vcpu_args_set(vcpu, 1, test);
 
 	vcpu_run_loop(vm, vcpu, test);
@@ -762,6 +827,25 @@ static void help(char *name)
 	.expected_events	= { 0 },					\
 }
 
+#define TEST_RO_MEMSLOT(_access, _mmio_handler, _mmio_exits)			\
+{										\
+	.name			= SCAT3(ro_memslot, _access, _with_af),		\
+	.data_memslot_flags	= KVM_MEM_READONLY,				\
+	.guest_prepare		= { _PREPARE(_access) },			\
+	.guest_test		= _access,					\
+	.mmio_handler		= _mmio_handler,				\
+	.expected_events	= { .mmio_exits = _mmio_exits },		\
+}
+
+#define TEST_RO_MEMSLOT_NO_SYNDROME(_access)					\
+{										\
+	.name			= SCAT2(ro_memslot_no_syndrome, _access),	\
+	.data_memslot_flags	= KVM_MEM_READONLY,				\
+	.guest_test		= _access,					\
+	.fail_vcpu_run_handler	= fail_vcpu_run_mmio_no_syndrome_handler,	\
+	.expected_events	= { .fail_vcpu_runs = 1 },			\
+}
+
 static struct test_desc tests[] = {
 
 	/* Check that HW is setting the Access Flag (AF) (sanity checks). */
@@ -830,6 +914,21 @@ static struct test_desc tests[] = {
 	TEST_DIRTY_LOG(guest_dc_zva, with_af, guest_check_write_in_dirty_log),
 	TEST_DIRTY_LOG(guest_st_preidx, with_af, guest_check_write_in_dirty_log),
 
+	/*
+	 * Try accesses when the data memslot is marked read-only (with
+	 * KVM_MEM_READONLY). Writes with a syndrome result in an MMIO exit,
+	 * writes with no syndrome (e.g., CAS) result in a failed vcpu run, and
+	 * reads/execs with and without syndroms do not fault.
+	 */
+	TEST_RO_MEMSLOT(guest_read64, 0, 0),
+	TEST_RO_MEMSLOT(guest_ld_preidx, 0, 0),
+	TEST_RO_MEMSLOT(guest_at, 0, 0),
+	TEST_RO_MEMSLOT(guest_exec, 0, 0),
+	TEST_RO_MEMSLOT(guest_write64, mmio_on_test_gpa_handler, 1),
+	TEST_RO_MEMSLOT_NO_SYNDROME(guest_dc_zva),
+	TEST_RO_MEMSLOT_NO_SYNDROME(guest_cas),
+	TEST_RO_MEMSLOT_NO_SYNDROME(guest_st_preidx),
+
 	{ 0 }
 };
 
-- 
2.37.2.789.g6183377224-goog

[PATCH v6 13/13] KVM: selftests: aarch64: Add mix of tests into page_fault_test

[Ricardo Koller]

Add some mix of tests into page_fault_test: memslots with all the
pairwise combinations of read-only, userfaultfd, and dirty-logging.  For
example, writing into a read-only memslot which has a hole handled with
userfaultfd.

Signed-off-by: Ricardo Koller <ricarkol@google.com>
---
 .../selftests/kvm/aarch64/page_fault_test.c   | 155 ++++++++++++++++++
 1 file changed, 155 insertions(+)

diff --git a/tools/testing/selftests/kvm/aarch64/page_fault_test.c b/tools/testing/selftests/kvm/aarch64/page_fault_test.c
index 39fc2103fdd6..60a6a8a45fa4 100644
--- a/tools/testing/selftests/kvm/aarch64/page_fault_test.c
+++ b/tools/testing/selftests/kvm/aarch64/page_fault_test.c
@@ -399,6 +399,12 @@ static void free_uffd(struct test_desc *test, struct uffd_desc *pt_uffd,
 	free(data_args.copy);
 }
 
+static int uffd_no_handler(int mode, int uffd, struct uffd_msg *msg)
+{
+	TEST_FAIL("There was no UFFD fault expected.");
+	return -1;
+}
+
 /* Returns false if the test should be skipped. */
 static bool punch_hole_in_memslot(struct kvm_vm *vm,
 				  struct userspace_mem_region *region)
@@ -827,6 +833,22 @@ static void help(char *name)
 	.expected_events	= { 0 },					\
 }
 
+#define TEST_UFFD_AND_DIRTY_LOG(_access, _with_af, _uffd_data_handler,		\
+				_uffd_faults, _test_check)			\
+{										\
+	.name			= SCAT3(uffd_and_dirty_log, _access, _with_af),	\
+	.data_memslot_flags	= KVM_MEM_LOG_DIRTY_PAGES,			\
+	.pt_memslot_flags	= KVM_MEM_LOG_DIRTY_PAGES,			\
+	.guest_prepare		= { _PREPARE(_with_af),				\
+				    _PREPARE(_access) },			\
+	.guest_test		= _access,					\
+	.mem_mark_cmd		= CMD_HOLE_DATA | CMD_HOLE_PT,			\
+	.guest_test_check	= { _CHECK(_with_af), _test_check },		\
+	.uffd_data_handler	= _uffd_data_handler,				\
+	.uffd_pt_handler	= uffd_pt_write_handler,			\
+	.expected_events	= { .uffd_faults = _uffd_faults, },		\
+}
+
 #define TEST_RO_MEMSLOT(_access, _mmio_handler, _mmio_exits)			\
 {										\
 	.name			= SCAT3(ro_memslot, _access, _with_af),		\
@@ -846,6 +868,59 @@ static void help(char *name)
 	.expected_events	= { .fail_vcpu_runs = 1 },			\
 }
 
+#define TEST_RO_MEMSLOT_AND_DIRTY_LOG(_access, _mmio_handler, _mmio_exits,	\
+				      _test_check)				\
+{										\
+	.name			= SCAT3(ro_memslot, _access, _with_af),		\
+	.data_memslot_flags	= KVM_MEM_READONLY | KVM_MEM_LOG_DIRTY_PAGES,	\
+	.pt_memslot_flags	= KVM_MEM_LOG_DIRTY_PAGES,			\
+	.guest_prepare		= { _PREPARE(_access) },			\
+	.guest_test		= _access,					\
+	.guest_test_check	= { _test_check },				\
+	.mmio_handler		= _mmio_handler,				\
+	.expected_events	= { .mmio_exits = _mmio_exits},			\
+}
+
+#define TEST_RO_MEMSLOT_NO_SYNDROME_AND_DIRTY_LOG(_access, _test_check)		\
+{										\
+	.name			= SCAT2(ro_memslot_no_syn_and_dlog, _access),	\
+	.data_memslot_flags	= KVM_MEM_READONLY | KVM_MEM_LOG_DIRTY_PAGES,	\
+	.pt_memslot_flags	= KVM_MEM_LOG_DIRTY_PAGES,			\
+	.guest_test		= _access,					\
+	.guest_test_check	= { _test_check },				\
+	.fail_vcpu_run_handler	= fail_vcpu_run_mmio_no_syndrome_handler,	\
+	.expected_events	= { .fail_vcpu_runs = 1 },			\
+}
+
+#define TEST_RO_MEMSLOT_AND_UFFD(_access, _mmio_handler, _mmio_exits,		\
+				 _uffd_data_handler, _uffd_faults)		\
+{										\
+	.name			= SCAT2(ro_memslot_uffd, _access),		\
+	.data_memslot_flags	= KVM_MEM_READONLY,				\
+	.mem_mark_cmd		= CMD_HOLE_DATA | CMD_HOLE_PT,			\
+	.guest_prepare		= { _PREPARE(_access) },			\
+	.guest_test		= _access,					\
+	.uffd_data_handler	= _uffd_data_handler,				\
+	.uffd_pt_handler	= uffd_pt_write_handler,			\
+	.mmio_handler		= _mmio_handler,				\
+	.expected_events	= { .mmio_exits = _mmio_exits,			\
+				    .uffd_faults = _uffd_faults },		\
+}
+
+#define TEST_RO_MEMSLOT_NO_SYNDROME_AND_UFFD(_access, _uffd_data_handler,	\
+					     _uffd_faults)			\
+{										\
+	.name			= SCAT2(ro_memslot_no_syndrome, _access),	\
+	.data_memslot_flags	= KVM_MEM_READONLY,				\
+	.mem_mark_cmd		= CMD_HOLE_DATA | CMD_HOLE_PT,			\
+	.guest_test		= _access,					\
+	.uffd_data_handler	= _uffd_data_handler,				\
+	.uffd_pt_handler	= uffd_pt_write_handler,			\
+	.fail_vcpu_run_handler	= fail_vcpu_run_mmio_no_syndrome_handler,	\
+	.expected_events	= { .fail_vcpu_runs = 1,			\
+				    .uffd_faults = _uffd_faults },		\
+}
+
 static struct test_desc tests[] = {
 
 	/* Check that HW is setting the Access Flag (AF) (sanity checks). */
@@ -914,6 +989,35 @@ static struct test_desc tests[] = {
 	TEST_DIRTY_LOG(guest_dc_zva, with_af, guest_check_write_in_dirty_log),
 	TEST_DIRTY_LOG(guest_st_preidx, with_af, guest_check_write_in_dirty_log),
 
+	/*
+	 * Access when the data and PT memslots are both marked for dirty
+	 * logging and UFFD at the same time. The expected result is that
+	 * writes should mark the dirty log and trigger a userfaultfd write
+	 * fault.  Reads/execs should result in a read userfaultfd fault, and
+	 * nothing in the dirty log.  Any S1PTW should result in a write in the
+	 * dirty log and a userfaultfd write.
+	 */
+	TEST_UFFD_AND_DIRTY_LOG(guest_read64, with_af, uffd_data_read_handler, 2,
+			guest_check_no_write_in_dirty_log),
+	/* no_af should also lead to a PT write. */
+	TEST_UFFD_AND_DIRTY_LOG(guest_read64, no_af, uffd_data_read_handler, 2,
+			guest_check_no_write_in_dirty_log),
+	TEST_UFFD_AND_DIRTY_LOG(guest_ld_preidx, with_af, uffd_data_read_handler,
+			2, guest_check_no_write_in_dirty_log),
+	TEST_UFFD_AND_DIRTY_LOG(guest_at, with_af, 0, 1,
+			guest_check_no_write_in_dirty_log),
+	TEST_UFFD_AND_DIRTY_LOG(guest_exec, with_af, uffd_data_read_handler, 2,
+			guest_check_no_write_in_dirty_log),
+	TEST_UFFD_AND_DIRTY_LOG(guest_write64, with_af, uffd_data_write_handler,
+			2, guest_check_write_in_dirty_log),
+	TEST_UFFD_AND_DIRTY_LOG(guest_cas, with_af, uffd_data_read_handler, 2,
+			guest_check_write_in_dirty_log),
+	TEST_UFFD_AND_DIRTY_LOG(guest_dc_zva, with_af, uffd_data_write_handler,
+			2, guest_check_write_in_dirty_log),
+	TEST_UFFD_AND_DIRTY_LOG(guest_st_preidx, with_af,
+			uffd_data_write_handler, 2,
+			guest_check_write_in_dirty_log),
+
 	/*
 	 * Try accesses when the data memslot is marked read-only (with
 	 * KVM_MEM_READONLY). Writes with a syndrome result in an MMIO exit,
@@ -929,6 +1033,57 @@ static struct test_desc tests[] = {
 	TEST_RO_MEMSLOT_NO_SYNDROME(guest_cas),
 	TEST_RO_MEMSLOT_NO_SYNDROME(guest_st_preidx),
 
+	/*
+	 * Access when both the data memslot is both read-only and marked for
+	 * dirty logging at the same time. The expected result is that for
+	 * writes there should be no write in the dirty log. The readonly
+	 * handling is the same as if the memslot was not marked for dirty
+	 * logging: writes with a syndrome result in an MMIO exit, and writes
+	 * with no syndrome result in a failed vcpu run.
+	 */
+	TEST_RO_MEMSLOT_AND_DIRTY_LOG(guest_read64, 0, 0,
+			guest_check_no_write_in_dirty_log),
+	TEST_RO_MEMSLOT_AND_DIRTY_LOG(guest_ld_preidx, 0, 0,
+			guest_check_no_write_in_dirty_log),
+	TEST_RO_MEMSLOT_AND_DIRTY_LOG(guest_at, 0, 0,
+			guest_check_no_write_in_dirty_log),
+	TEST_RO_MEMSLOT_AND_DIRTY_LOG(guest_exec, 0, 0,
+			guest_check_no_write_in_dirty_log),
+	TEST_RO_MEMSLOT_AND_DIRTY_LOG(guest_write64, mmio_on_test_gpa_handler,
+			1, guest_check_no_write_in_dirty_log),
+	TEST_RO_MEMSLOT_NO_SYNDROME_AND_DIRTY_LOG(guest_dc_zva,
+			guest_check_no_write_in_dirty_log),
+	TEST_RO_MEMSLOT_NO_SYNDROME_AND_DIRTY_LOG(guest_cas,
+			guest_check_no_write_in_dirty_log),
+	TEST_RO_MEMSLOT_NO_SYNDROME_AND_DIRTY_LOG(guest_st_preidx,
+			guest_check_no_write_in_dirty_log),
+
+	/*
+	 * Access when the data memslot is both read-only and punched with
+	 * holes tracked with userfaultfd.  The expected result is the union of
+	 * both userfaultfd and read-only behaviors. For example, write
+	 * accesses result in a userfaultfd write fault and an MMIO exit.
+	 * Writes with no syndrome result in a failed vcpu run and no
+	 * userfaultfd write fault. Reads result in userfaultfd getting
+	 * triggered.
+	 */
+	TEST_RO_MEMSLOT_AND_UFFD(guest_read64, 0, 0,
+			uffd_data_read_handler, 2),
+	TEST_RO_MEMSLOT_AND_UFFD(guest_ld_preidx, 0, 0,
+			uffd_data_read_handler, 2),
+	TEST_RO_MEMSLOT_AND_UFFD(guest_at, 0, 0,
+			uffd_no_handler, 1),
+	TEST_RO_MEMSLOT_AND_UFFD(guest_exec, 0, 0,
+			uffd_data_read_handler, 2),
+	TEST_RO_MEMSLOT_AND_UFFD(guest_write64, mmio_on_test_gpa_handler, 1,
+			uffd_data_write_handler, 2),
+	TEST_RO_MEMSLOT_NO_SYNDROME_AND_UFFD(guest_cas,
+			uffd_data_read_handler, 2),
+	TEST_RO_MEMSLOT_NO_SYNDROME_AND_UFFD(guest_dc_zva,
+			uffd_no_handler, 1),
+	TEST_RO_MEMSLOT_NO_SYNDROME_AND_UFFD(guest_st_preidx,
+			uffd_no_handler, 1),
+
 	{ 0 }
 };
 
-- 
2.37.2.789.g6183377224-goog

Re: [PATCH v6 09/13] KVM: selftests: aarch64: Add aarch64/page_fault_test

[Oliver Upton]

On Tue, Sep 06, 2022 at 06:09:26PM +0000, Ricardo Koller wrote:
> Add a new test for stage 2 faults when using different combinations of
> guest accesses (e.g., write, S1PTW), backing source type (e.g., anon)
> and types of faults (e.g., read on hugetlbfs with a hole). The next
> commits will add different handling methods and more faults (e.g., uffd
> and dirty logging). This first commit starts by adding two sanity checks
> for all types of accesses: AF setting by the hw, and accessing memslots
> with holes.
> 
> Signed-off-by: Ricardo Koller <ricarkol@google.com>

Hey Ricardo,

You'll need to update .gitignore for this patch. Additionally, building
this test throws the following compiler warning:

In function ‘load_exec_code_for_test’,
    inlined from ‘run_test’ at aarch64/page_fault_test.c:745:2:
aarch64/page_fault_test.c:545:9: warning: array subscript ‘long unsigned int[0]’ is partly outside array bounds of ‘unsigned char[1]’ [-Warray-bounds]
  545 |         memcpy(code, c, 8);
      |         ^~~~~~~~~~~~~~~~~~

I've fixed both of these in the appended diff, feel free to squash.

--
Thanks,
Oliver

From 0a5d3710b9043ae8fe5a9d7cc48eb854d1b7b746 Mon Sep 17 00:00:00 2001
From: Oliver Upton <oliver.upton@linux.dev>
Date: Sat, 17 Sep 2022 21:38:11 +0000
Subject: [PATCH] fixup! KVM: selftests: aarch64: Add aarch64/page_fault_test

---
 tools/testing/selftests/kvm/.gitignore               |  1 +
 .../testing/selftests/kvm/aarch64/page_fault_test.c  | 12 +++---------
 2 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index d625a3f83780..7a9022cfa033 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -3,6 +3,7 @@
 /aarch64/debug-exceptions
 /aarch64/get-reg-list
 /aarch64/hypercalls
+/aarch64/page_fault_test
 /aarch64/psci_test
 /aarch64/vcpu_width_config
 /aarch64/vgic_init
diff --git a/tools/testing/selftests/kvm/aarch64/page_fault_test.c b/tools/testing/selftests/kvm/aarch64/page_fault_test.c
index 60a6a8a45fa4..5ef2a7b941ec 100644
--- a/tools/testing/selftests/kvm/aarch64/page_fault_test.c
+++ b/tools/testing/selftests/kvm/aarch64/page_fault_test.c
@@ -512,7 +512,7 @@ void fail_vcpu_run_mmio_no_syndrome_handler(int ret)
 	events.fail_vcpu_runs += 1;
 }
 
-extern unsigned char __exec_test;
+extern uint64_t __exec_test;
 
 void noinline __return_0x77(void)
 {
@@ -526,7 +526,7 @@ void noinline __return_0x77(void)
  */
 static void load_exec_code_for_test(struct kvm_vm *vm)
 {
-	uint64_t *code, *c;
+	uint64_t *code;
 	struct userspace_mem_region *region;
 	void *hva;
 
@@ -536,13 +536,7 @@ static void load_exec_code_for_test(struct kvm_vm *vm)
 	assert(TEST_EXEC_GVA - TEST_GVA);
 	code = hva + 8;
 
-	/*
-	 * We need the cast to be separate in order for the compiler to not
-	 * complain with: "‘memcpy’ forming offset [1, 7] is out of the bounds
-	 * [0, 1] of object ‘__exec_test’ with type ‘unsigned char’"
-	 */
-	c = (uint64_t *)&__exec_test;
-	memcpy(code, c, 8);
+	*code = __exec_test;
 }
 
 static void setup_abort_handlers(struct kvm_vm *vm, struct kvm_vcpu *vcpu,
-- 
2.37.3.968.ga6b4b080e4-goog

Re: [PATCH v6 01/13] KVM: selftests: Add a userfaultfd library

[Oliver Upton]

Hi Ricardo,

On Tue, Sep 06, 2022 at 06:09:18PM +0000, Ricardo Koller wrote:
> Move the generic userfaultfd code out of demand_paging_test.c into a
> common library, userfaultfd_util. This library consists of a setup and a
> stop function. The setup function starts a thread for handling page
> faults using the handler callback function. This setup returns a
> uffd_desc object which is then used in the stop function (to wait and
> destroy the threads).
> 
> Reviewed-by: Ben Gardon <bgardon@google.com>
> Signed-off-by: Ricardo Koller <ricarkol@google.com>
> ---

[...]

> diff --git a/tools/testing/selftests/kvm/include/userfaultfd_util.h b/tools/testing/selftests/kvm/include/userfaultfd_util.h
> new file mode 100644
> index 000000000000..a1a386c083b0
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/include/userfaultfd_util.h
> @@ -0,0 +1,46 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * KVM userfaultfd util
> + * Adapted from demand_paging_test.c

nit: Don't reference demand_paging_test.c, as it won't make sense unless
the reader also looks at this diff.

> + *
> + * Copyright (C) 2018, Red Hat, Inc.
> + * Copyright (C) 2019-2022 Google LLC
> + */

[...]

> 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..4395032ccbe4
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/lib/userfaultfd_util.c
> @@ -0,0 +1,187 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * KVM userfaultfd util
> + * Adapted from demand_paging_test.c
> + *
> + * Copyright (C) 2018, Red Hat, Inc.
> + * Copyright (C) 2019, Google, Inc.
> + * Copyright (C) 2022, Google, Inc.

nit: use the same copyrights as the header file.

With that:

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>

Re: [PATCH v6 02/13] KVM: selftests: aarch64: Add virt_get_pte_hva() library function

[Oliver Upton]

On Tue, Sep 06, 2022 at 06:09:19PM +0000, Ricardo Koller wrote:
> Add a library function to get the PTE (a host virtual address) of a
> given GVA.  This will be used in a future commit by a test to clear and
> check the access flag of a particular page.
> 
> Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
> Signed-off-by: Ricardo Koller <ricarkol@google.com>

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>

--
Thanks,
Oliver

Re: [PATCH v6 06/13] KVM: selftests: Stash backing_src_type in struct userspace_mem_region

[Oliver Upton]

On Tue, Sep 06, 2022 at 06:09:23PM +0000, Ricardo Koller wrote:
> Add the backing_src_type into struct userspace_mem_region. This struct already
> stores a lot of info about memory regions, except the backing source type.
> This info will be used by a future commit in order to determine the method for
> punching a hole.
> 
> Signed-off-by: Ricardo Koller <ricarkol@google.com>

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>

--
Thanks,
Oliver

Re: [PATCH v6 07/13] KVM: selftests: Change ____vm_create() to take struct kvm_vm_mem_params

[Andrew Jones]

On Tue, Sep 06, 2022 at 06:09:24PM +0000, Ricardo Koller wrote:
> The vm_create() helpers are hardcoded to place most page types (code,
> page-tables, stacks, etc) in the same memslot #0, and always backed with
> anonymous 4K.  There are a couple of issues with that.  First, tests willing to
> differ a bit, like placing page-tables in a different backing source type must
> replicate much of what's already done by the vm_create() functions.  Second,
> the hardcoded assumption of memslot #0 holding most things is spreaded
> everywhere; this makes it very hard to change.
> 
> Fix the above issues by having selftests specify how they want memory to be
> laid out: define the memory regions to use for code, pt (page-tables), and
> data. Introduce a new structure, struct kvm_vm_mem_params, that defines: guest
> mode, a list of memory region descriptions, and some fields specifying what
> regions to use for code, pt, and data.
> 
> There is no functional change intended. The current commit adds a default
> struct kvm_vm_mem_params that lays out memory exactly as before. The next
> commit will change the allocators to get the region they should be using,
> e.g.,: like the page table allocators using the pt memslot.
> 
> Cc: Sean Christopherson <seanjc@google.com>
> Cc: Andrew Jones <andrew.jones@linux.dev>
> Signed-off-by: Ricardo Koller <ricarkol@google.com>
> ---
>  .../selftests/kvm/include/kvm_util_base.h     | 51 +++++++++++++++-
>  .../selftests/kvm/lib/aarch64/processor.c     |  3 +-
>  tools/testing/selftests/kvm/lib/kvm_util.c    | 58 ++++++++++++++++---
>  3 files changed, 102 insertions(+), 10 deletions(-)
>

Reviewed-by: Andrew Jones <andrew.jones@linux.dev>

Re: [PATCH v6 08/13] KVM: selftests: Use the right memslot for code, page-tables, and data allocations

[Andrew Jones]

On Tue, Sep 06, 2022 at 06:09:25PM +0000, Ricardo Koller wrote:
> The previous commit added support for callers of ____vm_create() to specify
> what memslots to use for code, page-tables, and data allocations. Change
> them accordingly:
> 
> - stacks, code, and exception tables use the code memslot
> - page tables and the pgd use the pt memslot
> - data (anything allocated with vm_vaddr_alloc()) uses the data memslot
> 
> No functional change intended. All allocators keep using memslot #0.
> 
> Cc: Sean Christopherson <seanjc@google.com>
> Cc: Andrew Jones <andrew.jones@linux.dev>
> Signed-off-by: Ricardo Koller <ricarkol@google.com>
> ---
>  .../selftests/kvm/include/kvm_util_base.h     |  3 +
>  .../selftests/kvm/lib/aarch64/processor.c     | 11 ++--
>  tools/testing/selftests/kvm/lib/elf.c         |  3 +-
>  tools/testing/selftests/kvm/lib/kvm_util.c    | 57 ++++++++++++-------
>  .../selftests/kvm/lib/riscv/processor.c       |  7 ++-
>  .../selftests/kvm/lib/s390x/processor.c       |  7 ++-
>  .../selftests/kvm/lib/x86_64/processor.c      | 13 +++--
>  7 files changed, 61 insertions(+), 40 deletions(-)
>

Reviewed-by: Andrew Jones <andrew.jones@linux.dev>

Re: [PATCH v6 00/13] KVM: selftests: Add aarch64/page_fault_test

[Marc Zyngier]

On Tue, 6 Sep 2022 18:09:17 +0000, Ricardo Koller wrote:
> 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). Some interesting combinations are:
> 
> [...]

Given how long this has been around, I've picked this series up, applying
Oliver's fixes in the process. Any additional fixes will be added on top.

Applied to next, thanks!

[01/13] KVM: selftests: Add a userfaultfd library
        commit: b9e9f0060d69ace412846b3dda318189e74d80ea
[02/13] KVM: selftests: aarch64: Add virt_get_pte_hva() library function
        commit: b3e02786e384d83637fc29dca2af9604a6314e62
[03/13] KVM: selftests: Add missing close and munmap in __vm_mem_region_delete()
        commit: 77c071a5376c9fdc0c510138d081af5e6ead754d
[04/13] KVM: selftests: aarch64: Construct DEFAULT_MAIR_EL1 using sysreg.h macros
        commit: a68c2b6545af95729eb57fe39f173557d1f22649
[05/13] tools: Copy bitfield.h from the kernel sources
        commit: 8998ed5834af0a9cc3de8d5bd485576c654620fc
[06/13] KVM: selftests: Stash backing_src_type in struct userspace_mem_region
        commit: 20a8d07c0828592d72c756c98f2708e905bfabd3
[07/13] KVM: selftests: Change ____vm_create() to take struct kvm_vm_mem_params
        commit: cb7f9c457b94b2ad71eaf9621a9e7f3e9c3832db
[08/13] KVM: selftests: Use the right memslot for code, page-tables, and data allocations
        commit: 72ad71ddb5fae4dc26a2fa7e885213598baab9ad
[09/13] KVM: selftests: aarch64: Add aarch64/page_fault_test
        commit: fa7b86adf85be5de36a797df7b1509542af1f119
[10/13] KVM: selftests: aarch64: Add userfaultfd tests into page_fault_test
        commit: 596fcc0f6888241b0b2f02577a2b608f274b299d
[11/13] KVM: selftests: aarch64: Add dirty logging tests into page_fault_test
        commit: 0740d435146f69be9950df5dd45a31fbaec943ba
[12/13] KVM: selftests: aarch64: Add readonly memslot tests into page_fault_test
        commit: a9246644455d51faa4063749bb17aa7e060adc70
[13/13] KVM: selftests: aarch64: Add mix of tests into page_fault_test
        commit: 383d48a1442ca477732ea77d6231b3cc73b9d7f8

Cheers,

	M.

Re: [PATCH v6 07/13] KVM: selftests: Change ____vm_create() to take struct kvm_vm_mem_params

[Sean Christopherson]

On Tue, Sep 06, 2022, Ricardo Koller wrote:
> @@ -637,19 +658,45 @@ vm_paddr_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
>  			      vm_paddr_t paddr_min, uint32_t memslot);
>  vm_paddr_t vm_alloc_page_table(struct kvm_vm *vm);
>  
> +struct kvm_vm_mem_params {
> +	enum vm_guest_mode mode;
> +
> +	struct {
> +		enum vm_mem_backing_src_type src_type;
> +		uint64_t guest_paddr;
> +		/*
> +		 * KVM region slot (same meaning as in struct
> +		 * kvm_userspace_memory_region).
> +		 */
> +		uint32_t slot;
> +		uint64_t npages;
> +		uint32_t flags;
> +		bool enabled;

"enabled" is unnecessary, just have ____vm_create() skip over regions with npages=0.
Likely ends up being a moot point though.

> +	} region[NR_MEM_REGIONS];
> +
> +	/* Each region type points to a region in the above array. */
> +	uint16_t region_idx[NR_MEM_REGIONS];

Eww.  This is going to be super confusing and it's one more thing for tests to
screw up.  And open coding the indices for region[] is beyond gross.

> +};
> +
> +extern struct kvm_vm_mem_params kvm_vm_mem_default;
> +
>  /*
>   * ____vm_create() does KVM_CREATE_VM and little else.  __vm_create() also
>   * loads the test binary into guest memory and creates an IRQ chip (x86 only).
>   * __vm_create() does NOT create vCPUs, @nr_runnable_vcpus is used purely to
>   * calculate the amount of memory needed for per-vCPU data, e.g. stacks.
>   */
> -struct kvm_vm *____vm_create(enum vm_guest_mode mode, uint64_t nr_pages);
> +struct kvm_vm *____vm_create(struct kvm_vm_mem_params *mem_params);
>  struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus,
>  			   uint64_t nr_extra_pages);
>  
>  static inline struct kvm_vm *vm_create_barebones(void)
>  {
> -	return ____vm_create(VM_MODE_DEFAULT, 0);
> +	struct kvm_vm_mem_params params_wo_memslots = {
> +		.mode = kvm_vm_mem_default.mode,
> +	};
> +
> +	return ____vm_create(&params_wo_memslots);

Very related to the above complaints, this is rather ugly.  I liked the idea of
passing a struct to __vm_create(), but passing it to ____vm_create() feels extremely
forced.

In an ideal world, my preference would still be to modify __vm_create() to take the
struct so that a test that wants to utilize different memslots doesn't need to
manually duplicate all the other stuff in __vm_create(), but that might end up
being too forced as well.  For now, I'm ok punting on that so the page_fault_test
can get merged.

Looking at this with fresh eyes, there's simply no reason ____vm_create() should be
creating memslots.  If this series first moves the memslot creation into __vm_create()
where it belongs (patch below), then there's no need to force ____vm_create() to take
a struct.  And if we punt on refactoring __vm_create(), then there's no need to
add kvm_vm_mem_default and no real need to add struct kvm_vm_mem_params either.

If/when there's a second test that wants fine-grained control over memslots then
we can figure out a proper API to share between page_fault_test and whatever the
new test is, but for now if page_fault_test is going to call ____vm_create()
directly, then I think it's easier to forego the common API and just have page_fault_test
and __vm_create() open code setting vm->memslots.

Alternatively, if we really want a common API right away, then we can add a helper
to populate the memory region + vm->memslots.

Option A (open code):

struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus,
			   uint64_t nr_extra_pages)
{
	uint64_t nr_pages = vm_nr_pages_required(mode, nr_runnable_vcpus,
						 nr_extra_pages);
	struct kvm_vm *vm;
	int i;

	vm = ____vm_create(mode);

	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, 0, 0, nr_pages, 0);

	for (i = 0; i < NR_MEM_REGIONS; i++)
		vm->memslots[i] = 0;

	kvm_vm_elf_load(vm, program_invocation_name);

#ifdef __x86_64__
	vm_create_irqchip(vm);
#endif
	return vm;
}

...

enum pf_test_memslots {
	CODE_MEMSLOT,
	PAGE_TABLE_MEMSLOT,
	DATA_MEMSLOT,
}

/* Create a code memslot at pfn=0, and data and PT ones at max_gfn. */
static void setup_memslots(struct kvm_vm *vm, struct test_params *p)
{
	uint64_t backing_src_pagesz = get_backing_src_pagesz(p->src_type);
	uint64_t guest_page_size = vm_guest_mode_params[mode].page_size;
	uint64_t max_gfn = get_max_gfn(mode);
	/* Enough for 2M of code when using 4K guest pages. */
	uint64_t code_npages = 512;
	uint64_t pt_size, data_size, data_gpa;

	/*
	 * This test requires 1 pgd, 2 pud, 4 pmd, and 6 pte pages when using
	 * VM_MODE_P48V48_4K. Note that the .text takes ~1.6MBs.  That's 13
	 * pages. VM_MODE_P48V48_4K is the mode with most PT pages; let's use
	 * twice that just in case.
	 */
	pt_size = 26 * guest_page_size;

	/* memslot sizes and gpa's must be aligned to the backing page size */
	pt_size = align_up(pt_size, backing_src_pagesz);
	data_size = align_up(guest_page_size, backing_src_pagesz);
	data_gpa = (max_gfn * guest_page_size) - data_size;
	data_gpa = align_down(data_gpa, backing_src_pagesz);

	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, 0, CODE_MEMSLOT,
				    code_npages, 0);
	vm->memslots[MEM_REGION_CODE] = CODE_MEMSLOT;

	vm_userspace_mem_region_add(vm, p->src_type, data_gpa - pt_size,
				    PAGE_TABLE_MEMSLOT, pt_size / guest_page_size,
				    p->test_desc->pt_memslot_flags);
	vm->memslots[MEM_REGION_PT] = PAGE_TABLE_MEMSLOT;

	vm_userspace_mem_region_add(vm, p->src_type, data_gpa, DATA_MEMSLOT,
				    data_size / guest_page_size,
				    p->test_desc->data_memslot_flags);
	vm->memslots[MEM_REGION_PT] = DATA_MEMSLOT;
}


static void run_test(enum vm_guest_mode mode, void *arg)
{
	struct test_params *p = (struct test_params *)arg;
	struct test_desc *test = p->test_desc;
	struct kvm_vm *vm;
	struct kvm_vcpu *vcpu;
	struct uffd_desc *pt_uffd, *data_uffd;

	print_test_banner(mode, p);

	vm = ____vm_create(mode);
	setup_memslots(vm, p);
	kvm_vm_elf_load(vm, program_invocation_name);
	vcpu = vm_vcpu_add(vm, 0, guest_code);

	...
}

Option B (helper):

enum kvm_mem_region_mask {
	MEM_REGION_CODE_MASK	= BIT(MEM_REGION_CODE),
	MEM_REGION_PT_MASK	= BIT(MEM_REGION_PT),
	MEM_REGION_DATA_MASK	= BIT(MEM_REGION_DATA),

	MEM_REGION_ALL_MASK	= MEM_REGION_CODE_MASK |
				  MEM_REGION_PT_MASK |
				  MEM_REGION_DATA_MASK,
};

void kvm_vm_add_mem_region(struct kvm_vm *vm, enum kvm_mem_region_mask type_mask,
			   enum vm_mem_backing_src_type src_type, uint32_t slot,
			   uint64_t guest_paddr, uint64_t nr_pages, uint32_t flags)
{
	int i;

	vm_userspace_mem_region_add(vm, src_type, guest_paddr, slot, nr_pages, 0);

	for (i = 0; i < NR_MEM_REGIONS; i++) {
		if (BIT(i) & type_mask)
			vm->memslots[i] = slot;
	}
}

struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus,
			   uint64_t nr_extra_pages)
{
	uint64_t nr_pages = vm_nr_pages_required(mode, nr_runnable_vcpus,
						 nr_extra_pages);
	struct kvm_vm *vm;
	int i;

	vm = ____vm_create(mode);

	kvm_vm_add_mem_region(vm, MEM_REGION_ALL_MASK, VM_MEM_SRC_ANONYMOUS, 0,
			      0, nr_pages, 0);

	kvm_vm_elf_load(vm, program_invocation_name);

#ifdef __x86_64__
	vm_create_irqchip(vm);
#endif
	return vm;
}

static void setup_memslots(struct kvm_vm *vm, struct test_params *p)
{
	...

	kvm_vm_add_mem_region(vm, MEM_REGION_CODE_MASK, VM_MEM_SRC_ANONYMOUS,
			      CODE_MEMSLOT, 0, code_npages, 0);

	kvm_vm_add_mem_region(vm, MEM_REGION_PT_MASK p->src_type,
			      PAGE_TABLE_MEMSLOT, data_gpa - pt_size,
			      pt_size / guest_page_size,
			      p->test_desc->pt_memslot_flags);

	kvm_vm_add_mem_region(vm, MEM_REGION_DATA_MASK, p->src_type,
			      DATA_MEMSLOT, data_gpa,
			      data_size / guest_page_size,
			      p->test_desc->data_memslot_flags);
}

---
 .../testing/selftests/kvm/include/kvm_util_base.h |  4 ++--
 tools/testing/selftests/kvm/lib/kvm_util.c        | 15 +++++++--------
 2 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
index 24fde97f6121..107cb87908f8 100644
--- a/tools/testing/selftests/kvm/include/kvm_util_base.h
+++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
@@ -642,13 +642,13 @@ vm_paddr_t vm_alloc_page_table(struct kvm_vm *vm);
  * __vm_create() does NOT create vCPUs, @nr_runnable_vcpus is used purely to
  * calculate the amount of memory needed for per-vCPU data, e.g. stacks.
  */
-struct kvm_vm *____vm_create(enum vm_guest_mode mode, uint64_t nr_pages);
+struct kvm_vm *____vm_create(enum vm_guest_mode mode);
 struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus,
 			   uint64_t nr_extra_pages);
 
 static inline struct kvm_vm *vm_create_barebones(void)
 {
-	return ____vm_create(VM_MODE_DEFAULT, 0);
+	return ____vm_create(VM_MODE_DEFAULT);
 }
 
 static inline struct kvm_vm *vm_create(uint32_t nr_runnable_vcpus)
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 9889fe0d8919..c761422faa17 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -143,13 +143,10 @@ const struct vm_guest_mode_params vm_guest_mode_params[] = {
 _Static_assert(sizeof(vm_guest_mode_params)/sizeof(struct vm_guest_mode_params) == NUM_VM_MODES,
 	       "Missing new mode params?");
 
-struct kvm_vm *____vm_create(enum vm_guest_mode mode, uint64_t nr_pages)
+struct kvm_vm *____vm_create(enum vm_guest_mode mode)
 {
 	struct kvm_vm *vm;
 
-	pr_debug("%s: mode='%s' pages='%ld'\n", __func__,
-		 vm_guest_mode_string(mode), nr_pages);
-
 	vm = calloc(1, sizeof(*vm));
 	TEST_ASSERT(vm != NULL, "Insufficient Memory");
 
@@ -245,9 +242,6 @@ struct kvm_vm *____vm_create(enum vm_guest_mode mode, uint64_t nr_pages)
 
 	/* Allocate and setup memory for guest. */
 	vm->vpages_mapped = sparsebit_alloc();
-	if (nr_pages != 0)
-		vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
-					    0, 0, nr_pages, 0);
 
 	return vm;
 }
@@ -294,7 +288,12 @@ struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus,
 						 nr_extra_pages);
 	struct kvm_vm *vm;
 
-	vm = ____vm_create(mode, nr_pages);
+	pr_debug("%s: mode='%s' pages='%ld'\n", __func__,
+		 vm_guest_mode_string(mode), nr_pages);
+
+	vm = ____vm_create(mode);
+
+	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, 0, 0, nr_pages, 0);
 
 	kvm_vm_elf_load(vm, program_invocation_name);
 

base-commit: 372d07084593dc7a399bf9bee815711b1fb1bcf2
-- 

Re: [PATCH v6 00/13] KVM: selftests: Add aarch64/page_fault_test

[Sean Christopherson]

On Mon, Sep 19, 2022, Marc Zyngier wrote:
> On Tue, 6 Sep 2022 18:09:17 +0000, Ricardo Koller wrote:
> > 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). Some interesting combinations are:
> > 
> > [...]
> 
> Given how long this has been around, I've picked this series up, applying
> Oliver's fixes in the process.

Any chance this can be undone?  A big reason why this is at v6 is because of the
common API changes, and due to KVM Forum I've effectively had three working days
since this was posted, and others have probably had even less, i.e. lack of reviews
on v6 isn't because no one cares.

It's not the end of the world if we have to fix things up on top, but we'd avoid
a decent amount of churn if we can instead unwind and do a v7.

Re: [PATCH v6 00/13] KVM: selftests: Add aarch64/page_fault_test

[Marc Zyngier]

On Mon, 19 Sep 2022 17:38:14 +0100,
Sean Christopherson <seanjc@google.com> wrote:
> 
> On Mon, Sep 19, 2022, Marc Zyngier wrote:
> > On Tue, 6 Sep 2022 18:09:17 +0000, Ricardo Koller wrote:
> > > 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). Some interesting combinations are:
> > > 
> > > [...]
> > 
> > Given how long this has been around, I've picked this series up, applying
> > Oliver's fixes in the process.
> 
> Any chance this can be undone?  A big reason why this is at v6 is
> because of the common API changes, and due to KVM Forum I've
> effectively had three working days since this was posted, and others
> have probably had even less, i.e. lack of reviews on v6 isn't
> because no one cares.

Hey, I'm still not back at work, and won't be for another week! But
fair enough, if there is going to be a respin, I'd rather see that
(and I'm less hung up on tests having been in -next for some time
before sending out a PR that eventually reaches Linus).

> It's not the end of the world if we have to fix things up on top,
> but we'd avoid a decent amount of churn if we can instead unwind and
> do a v7.

No skin off my nose, as this leaves on its own topic branch. Now
dropped.

	M.

-- 
Without deviation from the norm, progress is not possible.

Re: [PATCH v6 00/13] KVM: selftests: Add aarch64/page_fault_test

[Ricardo Koller]

On Mon, Sep 19, 2022 at 05:57:16PM +0100, Marc Zyngier wrote:
> On Mon, 19 Sep 2022 17:38:14 +0100,
> Sean Christopherson <seanjc@google.com> wrote:
> > 
> > On Mon, Sep 19, 2022, Marc Zyngier wrote:
> > > On Tue, 6 Sep 2022 18:09:17 +0000, Ricardo Koller wrote:
> > > > 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). Some interesting combinations are:
> > > > 
> > > > [...]
> > > 
> > > Given how long this has been around, I've picked this series up, applying
> > > Oliver's fixes in the process.
> > 
> > Any chance this can be undone?  A big reason why this is at v6 is
> > because of the common API changes, and due to KVM Forum I've
> > effectively had three working days since this was posted, and others
> > have probably had even less, i.e. lack of reviews on v6 isn't
> > because no one cares.
> 
> Hey, I'm still not back at work, and won't be for another week! But
> fair enough, if there is going to be a respin, I'd rather see that
> (and I'm less hung up on tests having been in -next for some time
> before sending out a PR that eventually reaches Linus).
> 
> > It's not the end of the world if we have to fix things up on top,
> > but we'd avoid a decent amount of churn if we can instead unwind and
> > do a v7.
> 
> No skin off my nose, as this leaves on its own topic branch. Now
> dropped.

Thank you both. Yes, this will make our lives easier (including getting
the changes internally).

Ricardo

> 
> 	M.
> 
> -- 
> Without deviation from the norm, progress is not possible.

Re: [PATCH v6 07/13] KVM: selftests: Change ____vm_create() to take struct kvm_vm_mem_params

[Ricardo Koller]

On Mon, Sep 19, 2022 at 04:28:26PM +0000, Sean Christopherson wrote:
> On Tue, Sep 06, 2022, Ricardo Koller wrote:
> > @@ -637,19 +658,45 @@ vm_paddr_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
> >  			      vm_paddr_t paddr_min, uint32_t memslot);
> >  vm_paddr_t vm_alloc_page_table(struct kvm_vm *vm);
> >  
> > +struct kvm_vm_mem_params {
> > +	enum vm_guest_mode mode;
> > +
> > +	struct {
> > +		enum vm_mem_backing_src_type src_type;
> > +		uint64_t guest_paddr;
> > +		/*
> > +		 * KVM region slot (same meaning as in struct
> > +		 * kvm_userspace_memory_region).
> > +		 */
> > +		uint32_t slot;
> > +		uint64_t npages;
> > +		uint32_t flags;
> > +		bool enabled;
> 
> "enabled" is unnecessary, just have ____vm_create() skip over regions with npages=0.
> Likely ends up being a moot point though.
> 
> > +	} region[NR_MEM_REGIONS];
> > +
> > +	/* Each region type points to a region in the above array. */
> > +	uint16_t region_idx[NR_MEM_REGIONS];
> 
> Eww.  This is going to be super confusing and it's one more thing for tests to
> screw up.  And open coding the indices for region[] is beyond gross.
> 
> > +};
> > +
> > +extern struct kvm_vm_mem_params kvm_vm_mem_default;
> > +
> >  /*
> >   * ____vm_create() does KVM_CREATE_VM and little else.  __vm_create() also
> >   * loads the test binary into guest memory and creates an IRQ chip (x86 only).
> >   * __vm_create() does NOT create vCPUs, @nr_runnable_vcpus is used purely to
> >   * calculate the amount of memory needed for per-vCPU data, e.g. stacks.
> >   */
> > -struct kvm_vm *____vm_create(enum vm_guest_mode mode, uint64_t nr_pages);
> > +struct kvm_vm *____vm_create(struct kvm_vm_mem_params *mem_params);
> >  struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus,
> >  			   uint64_t nr_extra_pages);
> >  
> >  static inline struct kvm_vm *vm_create_barebones(void)
> >  {
> > -	return ____vm_create(VM_MODE_DEFAULT, 0);
> > +	struct kvm_vm_mem_params params_wo_memslots = {
> > +		.mode = kvm_vm_mem_default.mode,
> > +	};
> > +
> > +	return ____vm_create(&params_wo_memslots);
> 
> Very related to the above complaints, this is rather ugly.  I liked the idea of
> passing a struct to __vm_create(), but passing it to ____vm_create() feels extremely
> forced.
> 
> In an ideal world, my preference would still be to modify __vm_create() to take the
> struct so that a test that wants to utilize different memslots doesn't need to
> manually duplicate all the other stuff in __vm_create(), but that might end up
> being too forced as well.  For now, I'm ok punting on that so the page_fault_test
> can get merged.
> 
> Looking at this with fresh eyes, there's simply no reason ____vm_create() should be
> creating memslots.  If this series first moves the memslot creation into __vm_create()
> where it belongs (patch below), then there's no need to force ____vm_create() to take
> a struct.  And if we punt on refactoring __vm_create(), then there's no need to
> add kvm_vm_mem_default and no real need to add struct kvm_vm_mem_params either.

I think I prefer option A below. And I will take the offer of punting on
refactoring __vm_create() for after page_fault_test.

Having a struct would be nice, as that will allow tests to do things
like: run with all these combinations of (backing_src, regions, ...).

Thanks for the review,
Ricardo

> 
> If/when there's a second test that wants fine-grained control over memslots then
> we can figure out a proper API to share between page_fault_test and whatever the
> new test is, but for now if page_fault_test is going to call ____vm_create()
> directly, then I think it's easier to forego the common API and just have page_fault_test
> and __vm_create() open code setting vm->memslots.
> 
> Alternatively, if we really want a common API right away, then we can add a helper
> to populate the memory region + vm->memslots.
> 
> Option A (open code):
> 
> struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus,
> 			   uint64_t nr_extra_pages)
> {
> 	uint64_t nr_pages = vm_nr_pages_required(mode, nr_runnable_vcpus,
> 						 nr_extra_pages);
> 	struct kvm_vm *vm;
> 	int i;
> 
> 	vm = ____vm_create(mode);
> 
> 	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, 0, 0, nr_pages, 0);
> 
> 	for (i = 0; i < NR_MEM_REGIONS; i++)
> 		vm->memslots[i] = 0;
> 
> 	kvm_vm_elf_load(vm, program_invocation_name);
> 
> #ifdef __x86_64__
> 	vm_create_irqchip(vm);
> #endif
> 	return vm;
> }
> 
> ...
> 
> enum pf_test_memslots {
> 	CODE_MEMSLOT,
> 	PAGE_TABLE_MEMSLOT,
> 	DATA_MEMSLOT,
> }
> 
> /* Create a code memslot at pfn=0, and data and PT ones at max_gfn. */
> static void setup_memslots(struct kvm_vm *vm, struct test_params *p)
> {
> 	uint64_t backing_src_pagesz = get_backing_src_pagesz(p->src_type);
> 	uint64_t guest_page_size = vm_guest_mode_params[mode].page_size;
> 	uint64_t max_gfn = get_max_gfn(mode);
> 	/* Enough for 2M of code when using 4K guest pages. */
> 	uint64_t code_npages = 512;
> 	uint64_t pt_size, data_size, data_gpa;
> 
> 	/*
> 	 * This test requires 1 pgd, 2 pud, 4 pmd, and 6 pte pages when using
> 	 * VM_MODE_P48V48_4K. Note that the .text takes ~1.6MBs.  That's 13
> 	 * pages. VM_MODE_P48V48_4K is the mode with most PT pages; let's use
> 	 * twice that just in case.
> 	 */
> 	pt_size = 26 * guest_page_size;
> 
> 	/* memslot sizes and gpa's must be aligned to the backing page size */
> 	pt_size = align_up(pt_size, backing_src_pagesz);
> 	data_size = align_up(guest_page_size, backing_src_pagesz);
> 	data_gpa = (max_gfn * guest_page_size) - data_size;
> 	data_gpa = align_down(data_gpa, backing_src_pagesz);
> 
> 	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, 0, CODE_MEMSLOT,
> 				    code_npages, 0);
> 	vm->memslots[MEM_REGION_CODE] = CODE_MEMSLOT;
> 
> 	vm_userspace_mem_region_add(vm, p->src_type, data_gpa - pt_size,
> 				    PAGE_TABLE_MEMSLOT, pt_size / guest_page_size,
> 				    p->test_desc->pt_memslot_flags);
> 	vm->memslots[MEM_REGION_PT] = PAGE_TABLE_MEMSLOT;
> 
> 	vm_userspace_mem_region_add(vm, p->src_type, data_gpa, DATA_MEMSLOT,
> 				    data_size / guest_page_size,
> 				    p->test_desc->data_memslot_flags);
> 	vm->memslots[MEM_REGION_PT] = DATA_MEMSLOT;
> }
> 
> 
> static void run_test(enum vm_guest_mode mode, void *arg)
> {
> 	struct test_params *p = (struct test_params *)arg;
> 	struct test_desc *test = p->test_desc;
> 	struct kvm_vm *vm;
> 	struct kvm_vcpu *vcpu;
> 	struct uffd_desc *pt_uffd, *data_uffd;
> 
> 	print_test_banner(mode, p);
> 
> 	vm = ____vm_create(mode);
> 	setup_memslots(vm, p);
> 	kvm_vm_elf_load(vm, program_invocation_name);
> 	vcpu = vm_vcpu_add(vm, 0, guest_code);
> 
> 	...
> }
> 
> Option B (helper):
> 
> enum kvm_mem_region_mask {
> 	MEM_REGION_CODE_MASK	= BIT(MEM_REGION_CODE),
> 	MEM_REGION_PT_MASK	= BIT(MEM_REGION_PT),
> 	MEM_REGION_DATA_MASK	= BIT(MEM_REGION_DATA),
> 
> 	MEM_REGION_ALL_MASK	= MEM_REGION_CODE_MASK |
> 				  MEM_REGION_PT_MASK |
> 				  MEM_REGION_DATA_MASK,
> };
> 
> void kvm_vm_add_mem_region(struct kvm_vm *vm, enum kvm_mem_region_mask type_mask,
> 			   enum vm_mem_backing_src_type src_type, uint32_t slot,
> 			   uint64_t guest_paddr, uint64_t nr_pages, uint32_t flags)
> {
> 	int i;
> 
> 	vm_userspace_mem_region_add(vm, src_type, guest_paddr, slot, nr_pages, 0);
> 
> 	for (i = 0; i < NR_MEM_REGIONS; i++) {
> 		if (BIT(i) & type_mask)
> 			vm->memslots[i] = slot;
> 	}
> }
> 
> struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus,
> 			   uint64_t nr_extra_pages)
> {
> 	uint64_t nr_pages = vm_nr_pages_required(mode, nr_runnable_vcpus,
> 						 nr_extra_pages);
> 	struct kvm_vm *vm;
> 	int i;
> 
> 	vm = ____vm_create(mode);
> 
> 	kvm_vm_add_mem_region(vm, MEM_REGION_ALL_MASK, VM_MEM_SRC_ANONYMOUS, 0,
> 			      0, nr_pages, 0);
> 
> 	kvm_vm_elf_load(vm, program_invocation_name);
> 
> #ifdef __x86_64__
> 	vm_create_irqchip(vm);
> #endif
> 	return vm;
> }
> 
> static void setup_memslots(struct kvm_vm *vm, struct test_params *p)
> {
> 	...
> 
> 	kvm_vm_add_mem_region(vm, MEM_REGION_CODE_MASK, VM_MEM_SRC_ANONYMOUS,
> 			      CODE_MEMSLOT, 0, code_npages, 0);
> 
> 	kvm_vm_add_mem_region(vm, MEM_REGION_PT_MASK p->src_type,
> 			      PAGE_TABLE_MEMSLOT, data_gpa - pt_size,
> 			      pt_size / guest_page_size,
> 			      p->test_desc->pt_memslot_flags);
> 
> 	kvm_vm_add_mem_region(vm, MEM_REGION_DATA_MASK, p->src_type,
> 			      DATA_MEMSLOT, data_gpa,
> 			      data_size / guest_page_size,
> 			      p->test_desc->data_memslot_flags);
> }
> 
> ---
>  .../testing/selftests/kvm/include/kvm_util_base.h |  4 ++--
>  tools/testing/selftests/kvm/lib/kvm_util.c        | 15 +++++++--------
>  2 files changed, 9 insertions(+), 10 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
> index 24fde97f6121..107cb87908f8 100644
> --- a/tools/testing/selftests/kvm/include/kvm_util_base.h
> +++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
> @@ -642,13 +642,13 @@ vm_paddr_t vm_alloc_page_table(struct kvm_vm *vm);
>   * __vm_create() does NOT create vCPUs, @nr_runnable_vcpus is used purely to
>   * calculate the amount of memory needed for per-vCPU data, e.g. stacks.
>   */
> -struct kvm_vm *____vm_create(enum vm_guest_mode mode, uint64_t nr_pages);
> +struct kvm_vm *____vm_create(enum vm_guest_mode mode);
>  struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus,
>  			   uint64_t nr_extra_pages);
>  
>  static inline struct kvm_vm *vm_create_barebones(void)
>  {
> -	return ____vm_create(VM_MODE_DEFAULT, 0);
> +	return ____vm_create(VM_MODE_DEFAULT);
>  }
>  
>  static inline struct kvm_vm *vm_create(uint32_t nr_runnable_vcpus)
> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> index 9889fe0d8919..c761422faa17 100644
> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> @@ -143,13 +143,10 @@ const struct vm_guest_mode_params vm_guest_mode_params[] = {
>  _Static_assert(sizeof(vm_guest_mode_params)/sizeof(struct vm_guest_mode_params) == NUM_VM_MODES,
>  	       "Missing new mode params?");
>  
> -struct kvm_vm *____vm_create(enum vm_guest_mode mode, uint64_t nr_pages)
> +struct kvm_vm *____vm_create(enum vm_guest_mode mode)
>  {
>  	struct kvm_vm *vm;
>  
> -	pr_debug("%s: mode='%s' pages='%ld'\n", __func__,
> -		 vm_guest_mode_string(mode), nr_pages);
> -
>  	vm = calloc(1, sizeof(*vm));
>  	TEST_ASSERT(vm != NULL, "Insufficient Memory");
>  
> @@ -245,9 +242,6 @@ struct kvm_vm *____vm_create(enum vm_guest_mode mode, uint64_t nr_pages)
>  
>  	/* Allocate and setup memory for guest. */
>  	vm->vpages_mapped = sparsebit_alloc();
> -	if (nr_pages != 0)
> -		vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
> -					    0, 0, nr_pages, 0);
>  
>  	return vm;
>  }
> @@ -294,7 +288,12 @@ struct kvm_vm *__vm_create(enum vm_guest_mode mode, uint32_t nr_runnable_vcpus,
>  						 nr_extra_pages);
>  	struct kvm_vm *vm;
>  
> -	vm = ____vm_create(mode, nr_pages);
> +	pr_debug("%s: mode='%s' pages='%ld'\n", __func__,
> +		 vm_guest_mode_string(mode), nr_pages);
> +
> +	vm = ____vm_create(mode);
> +
> +	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, 0, 0, nr_pages, 0);
>  
>  	kvm_vm_elf_load(vm, program_invocation_name);
>  
> 
> base-commit: 372d07084593dc7a399bf9bee815711b1fb1bcf2
> -- 
> 

Re: [PATCH v6 09/13] KVM: selftests: aarch64: Add aarch64/page_fault_test

[Ricardo Koller]

On Sat, Sep 17, 2022 at 09:58:28PM +0000, Oliver Upton wrote:
> On Tue, Sep 06, 2022 at 06:09:26PM +0000, Ricardo Koller wrote:
> > Add a new test for stage 2 faults when using different combinations of
> > guest accesses (e.g., write, S1PTW), backing source type (e.g., anon)
> > and types of faults (e.g., read on hugetlbfs with a hole). The next
> > commits will add different handling methods and more faults (e.g., uffd
> > and dirty logging). This first commit starts by adding two sanity checks
> > for all types of accesses: AF setting by the hw, and accessing memslots
> > with holes.
> > 
> > Signed-off-by: Ricardo Koller <ricarkol@google.com>
> 
> Hey Ricardo,
> 
> You'll need to update .gitignore for this patch. Additionally, building
> this test throws the following compiler warning:
> 
> In function ‘load_exec_code_for_test’,
>     inlined from ‘run_test’ at aarch64/page_fault_test.c:745:2:
> aarch64/page_fault_test.c:545:9: warning: array subscript ‘long unsigned int[0]’ is partly outside array bounds of ‘unsigned char[1]’ [-Warray-bounds]
>   545 |         memcpy(code, c, 8);
>       |         ^~~~~~~~~~~~~~~~~~
> 
> I've fixed both of these in the appended diff, feel free to squash.

Thanks, will do that.

> 
> --
> Thanks,
> Oliver
> 
> From 0a5d3710b9043ae8fe5a9d7cc48eb854d1b7b746 Mon Sep 17 00:00:00 2001
> From: Oliver Upton <oliver.upton@linux.dev>
> Date: Sat, 17 Sep 2022 21:38:11 +0000
> Subject: [PATCH] fixup! KVM: selftests: aarch64: Add aarch64/page_fault_test
> 
> ---
>  tools/testing/selftests/kvm/.gitignore               |  1 +
>  .../testing/selftests/kvm/aarch64/page_fault_test.c  | 12 +++---------
>  2 files changed, 4 insertions(+), 9 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
> index d625a3f83780..7a9022cfa033 100644
> --- a/tools/testing/selftests/kvm/.gitignore
> +++ b/tools/testing/selftests/kvm/.gitignore
> @@ -3,6 +3,7 @@
>  /aarch64/debug-exceptions
>  /aarch64/get-reg-list
>  /aarch64/hypercalls
> +/aarch64/page_fault_test
>  /aarch64/psci_test
>  /aarch64/vcpu_width_config
>  /aarch64/vgic_init
> diff --git a/tools/testing/selftests/kvm/aarch64/page_fault_test.c b/tools/testing/selftests/kvm/aarch64/page_fault_test.c
> index 60a6a8a45fa4..5ef2a7b941ec 100644
> --- a/tools/testing/selftests/kvm/aarch64/page_fault_test.c
> +++ b/tools/testing/selftests/kvm/aarch64/page_fault_test.c
> @@ -512,7 +512,7 @@ void fail_vcpu_run_mmio_no_syndrome_handler(int ret)
>  	events.fail_vcpu_runs += 1;
>  }
>  
> -extern unsigned char __exec_test;
> +extern uint64_t __exec_test;
>  
>  void noinline __return_0x77(void)
>  {
> @@ -526,7 +526,7 @@ void noinline __return_0x77(void)
>   */
>  static void load_exec_code_for_test(struct kvm_vm *vm)
>  {
> -	uint64_t *code, *c;
> +	uint64_t *code;
>  	struct userspace_mem_region *region;
>  	void *hva;
>  
> @@ -536,13 +536,7 @@ static void load_exec_code_for_test(struct kvm_vm *vm)
>  	assert(TEST_EXEC_GVA - TEST_GVA);
>  	code = hva + 8;
>  
> -	/*
> -	 * We need the cast to be separate in order for the compiler to not
> -	 * complain with: "‘memcpy’ forming offset [1, 7] is out of the bounds
> -	 * [0, 1] of object ‘__exec_test’ with type ‘unsigned char’"
> -	 */
> -	c = (uint64_t *)&__exec_test;
> -	memcpy(code, c, 8);
> +	*code = __exec_test;

I remember trying many ways of getting the compiler to not complain, I
must have tried this (wonder what happened). Anyway, gcc and clang are
happy with it.

>  }
>  
>  static void setup_abort_handlers(struct kvm_vm *vm, struct kvm_vcpu *vcpu,
> -- 
> 2.37.3.968.ga6b4b080e4-goog
> 

Re: [PATCH v6 09/13] KVM: selftests: aarch64: Add aarch64/page_fault_test

[Sean Christopherson]

On Mon, Sep 19, 2022, Ricardo Koller wrote:
> On Sat, Sep 17, 2022 at 09:58:28PM +0000, Oliver Upton wrote:
> > @@ -536,13 +536,7 @@ static void load_exec_code_for_test(struct kvm_vm *vm)
> >  	assert(TEST_EXEC_GVA - TEST_GVA);
> >  	code = hva + 8;
> >  
> > -	/*
> > -	 * We need the cast to be separate in order for the compiler to not
> > -	 * complain with: "‘memcpy’ forming offset [1, 7] is out of the bounds
> > -	 * [0, 1] of object ‘__exec_test’ with type ‘unsigned char’"
> > -	 */
> > -	c = (uint64_t *)&__exec_test;
> > -	memcpy(code, c, 8);
> > +	*code = __exec_test;
> 
> I remember trying many ways of getting the compiler to not complain, I
> must have tried this (wonder what happened). Anyway, gcc and clang are
> happy with it.

Alternatively, from a code documentation perspective it would be nice to capture
that the size isn't arbitrary.  E.g.

  typedef uint32_t aarch64_insn_t;

  extern aarch64_insn_t __exec_test[2];

  {
	void *code;

	memcpy(code, __exec_test, sizeof(__exec_test));
  }

Note, memcpy() is currently dangerous, but hopefully that will be remedied soonish[*]

[*] https://lore.kernel.org/all/20220908233134.3523339-1-seanjc@google.com