KVM: selftests: Add demand paging content to the demand paging test (4f72180e) · Commits · 戴 / test

tools/arch/x86/include/asm/unistd_64.h

+3 −0

Original line number	Diff line number	Diff line
		/* SPDX-License-Identifier: GPL-2.0 */
		#ifndef __NR_userfaultfd
		#define __NR_userfaultfd 282
		#endif
		#ifndef __NR_perf_event_open
		# define __NR_perf_event_open 298
		#endif

tools/testing/selftests/kvm/demand_paging_test.c

+206 −4

Original line number	Diff line number	Diff line
		@@ -11,16 +11,21 @@

		#include <stdio.h>
		#include <stdlib.h>
		#include <sys/syscall.h>
		#include <unistd.h>
		#include <asm/unistd.h>
		#include <time.h>
		#include <poll.h>
		#include <pthread.h>
		#include <linux/bitmap.h>
		#include <linux/bitops.h>
		#include <linux/userfaultfd.h>

		#include "test_util.h"
		#include "kvm_util.h"
		#include "processor.h"

		#ifdef __NR_userfaultfd
		#define VCPU_ID 1

		/* The memory slot index demand page */
		@@ -39,6 +44,8 @@ static uint64_t host_page_size;
		static uint64_t guest_page_size;
		static uint64_t guest_num_pages;

		static char *guest_data_prototype;

		/*
		* Guest physical memory offset of the testing memory slot.
		* This will be set to the topmost valid physical address minus
		@@ -110,13 +117,169 @@ static struct kvm_vm *create_vm(enum vm_guest_mode mode, uint32_t vcpuid,
		return vm;
		}

		static int handle_uffd_page_request(int uffd, uint64_t addr)
		{
		pid_t tid;
		struct uffdio_copy copy;
		int r;

		tid = syscall(__NR_gettid);

		copy.src = (uint64_t)guest_data_prototype;
		copy.dst = addr;
		copy.len = host_page_size;
		copy.mode = 0;

		r = ioctl(uffd, UFFDIO_COPY, &copy);
		if (r == -1) {
		DEBUG("Failed Paged in 0x%lx from thread %d with errno: %d\n",
		addr, tid, errno);
		return r;
		}

		return 0;
		}

		bool quit_uffd_thread;

		struct uffd_handler_args {
		int uffd;
		int pipefd;
		};

		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;
		int64_t pages = 0;

		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:
		DEBUG("poll err");
		continue;
		case 0:
		continue;
		case 1:
		break;
		default:
		DEBUG("Polling uffd returned %d", r);
		return NULL;
		}

		if (pollfd[0].revents & POLLERR) {
		DEBUG("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;
		DEBUG("Read of uffd gor errno %d", errno);
		return NULL;
		}

		if (r != sizeof(msg)) {
		DEBUG("Read on uffd returned unexpected size: %d bytes",
		r);
		return NULL;
		}

		if (!(msg.event & UFFD_EVENT_PAGEFAULT))
		continue;

		addr = msg.arg.pagefault.address;
		r = handle_uffd_page_request(uffd, addr);
		if (r < 0)
		return NULL;
		pages++;
		}

		return NULL;
		}

		static int setup_demand_paging(struct kvm_vm *vm,
		pthread_t *uffd_handler_thread, int pipefd)
		{
		int uffd;
		struct uffdio_api uffdio_api;
		struct uffdio_register uffdio_register;
		struct uffd_handler_args uffd_args;

		guest_data_prototype = malloc(host_page_size);
		TEST_ASSERT(guest_data_prototype,
		"Failed to allocate buffer for guest data pattern");
		memset(guest_data_prototype, 0xAB, host_page_size);

		uffd = syscall(__NR_userfaultfd, O_CLOEXEC \| O_NONBLOCK);
		if (uffd == -1) {
		DEBUG("uffd creation failed\n");
		return -1;
		}

		uffdio_api.api = UFFD_API;
		uffdio_api.features = 0;
		if (ioctl(uffd, UFFDIO_API, &uffdio_api) == -1) {
		DEBUG("ioctl uffdio_api failed\n");
		return -1;
		}

		uffdio_register.range.start = (uint64_t)host_test_mem;
		uffdio_register.range.len = host_num_pages * host_page_size;
		uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
		if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register) == -1) {
		DEBUG("ioctl uffdio_register failed\n");
		return -1;
		}

		if ((uffdio_register.ioctls & UFFD_API_RANGE_IOCTLS) !=
		UFFD_API_RANGE_IOCTLS) {
		DEBUG("unexpected userfaultfd ioctl set\n");
		return -1;
		}

		uffd_args.uffd = uffd;
		uffd_args.pipefd = pipefd;
		pthread_create(uffd_handler_thread, NULL, uffd_handler_thread_fn,
		&uffd_args);

		return 0;
		}

		#define GUEST_MEM_SHIFT 30 /* 1G */
		#define PAGE_SHIFT_4K 12

		static void run_test(enum vm_guest_mode mode)
		static void run_test(enum vm_guest_mode mode, bool use_uffd)
		{
		pthread_t vcpu_thread;
		pthread_t uffd_handler_thread;
		int pipefd[2];
		struct kvm_vm *vm;
		int r;

		/*
		* We reserve page table for 2 times of extra dirty mem which
		@@ -173,6 +336,16 @@ static void run_test(enum vm_guest_mode mode)
		/* Cache the HVA pointer of the region */
		host_test_mem = addr_gpa2hva(vm, (vm_paddr_t)guest_test_phys_mem);

		if (use_uffd) {
		/* Set up user fault fd to handle demand paging requests. */
		r = pipe2(pipefd, O_CLOEXEC \| O_NONBLOCK);
		TEST_ASSERT(!r, "Failed to set up pipefd");

		r = setup_demand_paging(vm, &uffd_handler_thread, pipefd[0]);
		if (r < 0)
		exit(-r);
		}

		#ifdef __x86_64__
		vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
		#endif
		@@ -191,8 +364,20 @@ static void run_test(enum vm_guest_mode mode)
		/* Wait for the vcpu thread to quit */
		pthread_join(vcpu_thread, NULL);

		if (use_uffd) {
		char c;

		/* Tell the user fault fd handler thread to quit */
		r = write(pipefd[1], &c, 1);
		TEST_ASSERT(r == 1, "Unable to write to pipefd");

		pthread_join(uffd_handler_thread, NULL);
		}

		ucall_uninit(vm);
		kvm_vm_free(vm);

		free(guest_data_prototype);
		}

		struct guest_mode {
		@@ -210,7 +395,7 @@ static void help(char *name)
		int i;

		puts("");
		printf("usage: %s [-h] [-m mode]\n", name);
		printf("usage: %s [-h] [-m mode] [-u]\n", name);
		printf(" -m: specify the guest mode ID to test\n"
		" (default: test all supported modes)\n"
		" This option may be used multiple times.\n"
		@@ -219,6 +404,7 @@ static void help(char *name)
		printf(" %d: %s%s\n", i, vm_guest_mode_string(i),
		guest_modes[i].supported ? " (supported)" : "");
		}
		printf(" -u: Use User Fault FD to handle vCPU page faults.\n");
		puts("");
		exit(0);
		}
		@@ -228,6 +414,7 @@ int main(int argc, char *argv[])
		bool mode_selected = false;
		unsigned int mode;
		int opt, i;
		bool use_uffd = false;

		#ifdef __x86_64__
		guest_mode_init(VM_MODE_PXXV48_4K, true, true);
		@@ -250,7 +437,7 @@ int main(int argc, char *argv[])
		guest_mode_init(VM_MODE_P40V48_4K, true, true);
		#endif

		while ((opt = getopt(argc, argv, "hm:")) != -1) {
		while ((opt = getopt(argc, argv, "hm:u")) != -1) {
		switch (opt) {
		case 'm':
		if (!mode_selected) {
		@@ -263,6 +450,9 @@ int main(int argc, char *argv[])
		"Guest mode ID %d too big", mode);
		guest_modes[mode].enabled = true;
		break;
		case 'u':
		use_uffd = true;
		break;
		case 'h':
		default:
		help(argv[0]);
		@@ -276,8 +466,20 @@ int main(int argc, char *argv[])
		TEST_ASSERT(guest_modes[i].supported,
		"Guest mode ID %d (%s) not supported.",
		i, vm_guest_mode_string(i));
		run_test(i);
		run_test(i, use_uffd);
		}

		return 0;
		}

		#else /* __NR_userfaultfd */

		#warning "missing __NR_userfaultfd definition"

		int main(void)
		{
		printf("skip: Skipping userfaultfd test (missing __NR_userfaultfd)\n");
		return KSFT_SKIP;
		}

		#endif /* __NR_userfaultfd */

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