1 files changed, 501 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/x86/xapic_ipi_test.c b/tools/testing/selftests/kvm/x86/xapic_ipi_test.c
new file mode 100644
index 000000000000..35cb9de54a82
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86/xapic_ipi_test.c
@@ -0,0 +1,501 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * xapic_ipi_test
+ *
+ * Copyright (C) 2020, Google LLC.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ *
+ * Test that when the APIC is in xAPIC mode, a vCPU can send an IPI to wake
+ * another vCPU that is halted when KVM's backing page for the APIC access
+ * address has been moved by mm.
+ *
+ * The test starts two vCPUs: one that sends IPIs and one that continually
+ * executes HLT. The sender checks that the halter has woken from the HLT and
+ * has reentered HLT before sending the next IPI. While the vCPUs are running,
+ * the host continually calls migrate_pages to move all of the process' pages
+ * amongst the available numa nodes on the machine.
+ *
+ * Migration is a command line option. When used on non-numa machines will 
+ * exit with error. Test is still usefull on non-numa for testing IPIs.
+ */
+#include <getopt.h>
+#include <pthread.h>
+#include <inttypes.h>
+#include <string.h>
+#include <time.h>
+
+#include "kvm_util.h"
+#include "numaif.h"
+#include "processor.h"
+#include "test_util.h"
+#include "vmx.h"
+
+/* Default running time for the test */
+#define DEFAULT_RUN_SECS 3
+
+/* Default delay between migrate_pages calls (microseconds) */
+#define DEFAULT_DELAY_USECS 500000
+
+/*
+ * Vector for IPI from sender vCPU to halting vCPU.
+ * Value is arbitrary and was chosen for the alternating bit pattern. Any
+ * value should work.
+ */
+#define IPI_VECTOR	 0xa5
+
+/*
+ * Incremented in the IPI handler. Provides evidence to the sender that the IPI
+ * arrived at the destination
+ */
+static volatile uint64_t ipis_rcvd;
+
+/* Data struct shared between host main thread and vCPUs */
+struct test_data_page {
+	uint32_t halter_apic_id;
+	volatile uint64_t hlt_count;
+	volatile uint64_t wake_count;
+	uint64_t ipis_sent;
+	uint64_t migrations_attempted;
+	uint64_t migrations_completed;
+	uint32_t icr;
+	uint32_t icr2;
+	uint32_t halter_tpr;
+	uint32_t halter_ppr;
+
+	/*
+	 *  Record local version register as a cross-check that APIC access
+	 *  worked. Value should match what KVM reports (APIC_VERSION in
+	 *  arch/x86/kvm/lapic.c). If test is failing, check that values match
+	 *  to determine whether APIC access exits are working.
+	 */
+	uint32_t halter_lvr;
+};
+
+struct thread_params {
+	struct test_data_page *data;
+	struct kvm_vcpu *vcpu;
+	uint64_t *pipis_rcvd; /* host address of ipis_rcvd global */
+};
+
+void verify_apic_base_addr(void)
+{
+	uint64_t msr = rdmsr(MSR_IA32_APICBASE);
+	uint64_t base = GET_APIC_BASE(msr);
+
+	GUEST_ASSERT(base == APIC_DEFAULT_GPA);
+}
+
+static void halter_guest_code(struct test_data_page *data)
+{
+	verify_apic_base_addr();
+	xapic_enable();
+
+	data->halter_apic_id = GET_APIC_ID_FIELD(xapic_read_reg(APIC_ID));
+	data->halter_lvr = xapic_read_reg(APIC_LVR);
+
+	/*
+	 * Loop forever HLTing and recording halts & wakes. Disable interrupts
+	 * each time around to minimize window between signaling the pending
+	 * halt to the sender vCPU and executing the halt. No need to disable on
+	 * first run as this vCPU executes first and the host waits for it to
+	 * signal going into first halt before starting the sender vCPU. Record
+	 * TPR and PPR for diagnostic purposes in case the test fails.
+	 */
+	for (;;) {
+		data->halter_tpr = xapic_read_reg(APIC_TASKPRI);
+		data->halter_ppr = xapic_read_reg(APIC_PROCPRI);
+		data->hlt_count++;
+		safe_halt();
+		cli();
+		data->wake_count++;
+	}
+}
+
+/*
+ * Runs on halter vCPU when IPI arrives. Write an arbitrary non-zero value to
+ * enable diagnosing errant writes to the APIC access address backing page in
+ * case of test failure.
+ */
+static void guest_ipi_handler(struct ex_regs *regs)
+{
+	ipis_rcvd++;
+	xapic_write_reg(APIC_EOI, 77);
+}
+
+static void sender_guest_code(struct test_data_page *data)
+{
+	uint64_t last_wake_count;
+	uint64_t last_hlt_count;
+	uint64_t last_ipis_rcvd_count;
+	uint32_t icr_val;
+	uint32_t icr2_val;
+	uint64_t tsc_start;
+
+	verify_apic_base_addr();
+	xapic_enable();
+
+	/*
+	 * Init interrupt command register for sending IPIs
+	 *
+	 * Delivery mode=fixed, per SDM:
+	 *   "Delivers the interrupt specified in the vector field to the target
+	 *    processor."
+	 *
+	 * Destination mode=physical i.e. specify target by its local APIC
+	 * ID. This vCPU assumes that the halter vCPU has already started and
+	 * set data->halter_apic_id.
+	 */
+	icr_val = (APIC_DEST_PHYSICAL | APIC_DM_FIXED | IPI_VECTOR);
+	icr2_val = SET_APIC_DEST_FIELD(data->halter_apic_id);
+	data->icr = icr_val;
+	data->icr2 = icr2_val;
+
+	last_wake_count = data->wake_count;
+	last_hlt_count = data->hlt_count;
+	last_ipis_rcvd_count = ipis_rcvd;
+	for (;;) {
+		/*
+		 * Send IPI to halter vCPU.
+		 * First IPI can be sent unconditionally because halter vCPU
+		 * starts earlier.
+		 */
+		xapic_write_reg(APIC_ICR2, icr2_val);
+		xapic_write_reg(APIC_ICR, icr_val);
+		data->ipis_sent++;
+
+		/*
+		 * Wait up to ~1 sec for halter to indicate that it has:
+		 * 1. Received the IPI
+		 * 2. Woken up from the halt
+		 * 3. Gone back into halt
+		 * Current CPUs typically run at 2.x Ghz which is ~2
+		 * billion ticks per second.
+		 */
+		tsc_start = rdtsc();
+		while (rdtsc() - tsc_start < 2000000000) {
+			if ((ipis_rcvd != last_ipis_rcvd_count) &&
+			    (data->wake_count != last_wake_count) &&
+			    (data->hlt_count != last_hlt_count))
+				break;
+		}
+
+		GUEST_ASSERT((ipis_rcvd != last_ipis_rcvd_count) &&
+			     (data->wake_count != last_wake_count) &&
+			     (data->hlt_count != last_hlt_count));
+
+		last_wake_count = data->wake_count;
+		last_hlt_count = data->hlt_count;
+		last_ipis_rcvd_count = ipis_rcvd;
+	}
+}
+
+static void *vcpu_thread(void *arg)
+{
+	struct thread_params *params = (struct thread_params *)arg;
+	struct kvm_vcpu *vcpu = params->vcpu;
+	struct ucall uc;
+	int old;
+	int r;
+
+	r = pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, &old);
+	TEST_ASSERT(r == 0,
+		    "pthread_setcanceltype failed on vcpu_id=%u with errno=%d",
+		    vcpu->id, r);
+
+	fprintf(stderr, "vCPU thread running vCPU %u\n", vcpu->id);
+	vcpu_run(vcpu);
+
+	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
+
+	if (get_ucall(vcpu, &uc) == UCALL_ABORT) {
+		TEST_ASSERT(false,
+			    "vCPU %u exited with error: %s.\n"
+			    "Sending vCPU sent %lu IPIs to halting vCPU\n"
+			    "Halting vCPU halted %lu times, woke %lu times, received %lu IPIs.\n"
+			    "Halter TPR=%#x PPR=%#x LVR=%#x\n"
+			    "Migrations attempted: %lu\n"
+			    "Migrations completed: %lu",
+			    vcpu->id, (const char *)uc.args[0],
+			    params->data->ipis_sent, params->data->hlt_count,
+			    params->data->wake_count,
+			    *params->pipis_rcvd, params->data->halter_tpr,
+			    params->data->halter_ppr, params->data->halter_lvr,
+			    params->data->migrations_attempted,
+			    params->data->migrations_completed);
+	}
+
+	return NULL;
+}
+
+static void cancel_join_vcpu_thread(pthread_t thread, struct kvm_vcpu *vcpu)
+{
+	void *retval;
+	int r;
+
+	r = pthread_cancel(thread);
+	TEST_ASSERT(r == 0,
+		    "pthread_cancel on vcpu_id=%d failed with errno=%d",
+		    vcpu->id, r);
+
+	r = pthread_join(thread, &retval);
+	TEST_ASSERT(r == 0,
+		    "pthread_join on vcpu_id=%d failed with errno=%d",
+		    vcpu->id, r);
+	TEST_ASSERT(retval == PTHREAD_CANCELED,
+		    "expected retval=%p, got %p", PTHREAD_CANCELED,
+		    retval);
+}
+
+void do_migrations(struct test_data_page *data, int run_secs, int delay_usecs,
+		   uint64_t *pipis_rcvd)
+{
+	long pages_not_moved;
+	unsigned long nodemask = 0;
+	unsigned long nodemasks[sizeof(nodemask) * 8];
+	int nodes = 0;
+	time_t start_time, last_update, now;
+	time_t interval_secs = 1;
+	int i, r;
+	int from, to;
+	unsigned long bit;
+	uint64_t hlt_count;
+	uint64_t wake_count;
+	uint64_t ipis_sent;
+
+	fprintf(stderr, "Calling migrate_pages every %d microseconds\n",
+		delay_usecs);
+
+	/* Get set of first 64 numa nodes available */
+	r = get_mempolicy(NULL, &nodemask, sizeof(nodemask) * 8,
+			  0, MPOL_F_MEMS_ALLOWED);
+	TEST_ASSERT(r == 0, "get_mempolicy failed errno=%d", errno);
+
+	fprintf(stderr, "Numa nodes found amongst first %lu possible nodes "
+		"(each 1-bit indicates node is present): %#lx\n",
+		sizeof(nodemask) * 8, nodemask);
+
+	/* Init array of masks containing a single-bit in each, one for each
+	 * available node. migrate_pages called below requires specifying nodes
+	 * as bit masks.
+	 */
+	for (i = 0, bit = 1; i < sizeof(nodemask) * 8; i++, bit <<= 1) {
+		if (nodemask & bit) {
+			nodemasks[nodes] = nodemask & bit;
+			nodes++;
+		}
+	}
+
+	TEST_ASSERT(nodes > 1,
+		    "Did not find at least 2 numa nodes. Can't do migration");
+
+	fprintf(stderr, "Migrating amongst %d nodes found\n", nodes);
+
+	from = 0;
+	to = 1;
+	start_time = time(NULL);
+	last_update = start_time;
+
+	ipis_sent = data->ipis_sent;
+	hlt_count = data->hlt_count;
+	wake_count = data->wake_count;
+
+	while ((int)(time(NULL) - start_time) < run_secs) {
+		data->migrations_attempted++;
+
+		/*
+		 * migrate_pages with PID=0 will migrate all pages of this
+		 * process between the nodes specified as bitmasks. The page
+		 * backing the APIC access address belongs to this process
+		 * because it is allocated by KVM in the context of the
+		 * KVM_CREATE_VCPU ioctl. If that assumption ever changes this
+		 * test may break or give a false positive signal.
+		 */
+		pages_not_moved = migrate_pages(0, sizeof(nodemasks[from]),
+						&nodemasks[from],
+						&nodemasks[to]);
+		if (pages_not_moved < 0)
+			fprintf(stderr,
+				"migrate_pages failed, errno=%d\n", errno);
+		else if (pages_not_moved > 0)
+			fprintf(stderr,
+				"migrate_pages could not move %ld pages\n",
+				pages_not_moved);
+		else
+			data->migrations_completed++;
+
+		from = to;
+		to++;
+		if (to == nodes)
+			to = 0;
+
+		now = time(NULL);
+		if (((now - start_time) % interval_secs == 0) &&
+		    (now != last_update)) {
+			last_update = now;
+			fprintf(stderr,
+				"%lu seconds: Migrations attempted=%lu completed=%lu, "
+				"IPIs sent=%lu received=%lu, HLTs=%lu wakes=%lu\n",
+				now - start_time, data->migrations_attempted,
+				data->migrations_completed,
+				data->ipis_sent, *pipis_rcvd,
+				data->hlt_count, data->wake_count);
+
+			TEST_ASSERT(ipis_sent != data->ipis_sent &&
+				    hlt_count != data->hlt_count &&
+				    wake_count != data->wake_count,
+				    "IPI, HLT and wake count have not increased "
+				    "in the last %lu seconds. "
+				    "HLTer is likely hung.", interval_secs);
+
+			ipis_sent = data->ipis_sent;
+			hlt_count = data->hlt_count;
+			wake_count = data->wake_count;
+		}
+		usleep(delay_usecs);
+	}
+}
+
+void get_cmdline_args(int argc, char *argv[], int *run_secs,
+		      bool *migrate, int *delay_usecs)
+{
+	for (;;) {
+		int opt = getopt(argc, argv, "s:d:m");
+
+		if (opt == -1)
+			break;
+		switch (opt) {
+		case 's':
+			*run_secs = parse_size(optarg);
+			break;
+		case 'm':
+			*migrate = true;
+			break;
+		case 'd':
+			*delay_usecs = parse_size(optarg);
+			break;
+		default:
+			TEST_ASSERT(false,
+				    "Usage: -s <runtime seconds>. Default is %d seconds.\n"
+				    "-m adds calls to migrate_pages while vCPUs are running."
+				    " Default is no migrations.\n"
+				    "-d <delay microseconds> - delay between migrate_pages() calls."
+				    " Default is %d microseconds.",
+				    DEFAULT_RUN_SECS, DEFAULT_DELAY_USECS);
+		}
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	int r;
+	int wait_secs;
+	const int max_halter_wait = 10;
+	int run_secs = 0;
+	int delay_usecs = 0;
+	struct test_data_page *data;
+	vm_vaddr_t test_data_page_vaddr;
+	bool migrate = false;
+	pthread_t threads[2];
+	struct thread_params params[2];
+	struct kvm_vm *vm;
+	uint64_t *pipis_rcvd;
+
+	get_cmdline_args(argc, argv, &run_secs, &migrate, &delay_usecs);
+	if (run_secs <= 0)
+		run_secs = DEFAULT_RUN_SECS;
+	if (delay_usecs <= 0)
+		delay_usecs = DEFAULT_DELAY_USECS;
+
+	vm = vm_create_with_one_vcpu(&params[0].vcpu, halter_guest_code);
+
+	vm_install_exception_handler(vm, IPI_VECTOR, guest_ipi_handler);
+
+	virt_pg_map(vm, APIC_DEFAULT_GPA, APIC_DEFAULT_GPA);
+
+	params[1].vcpu = vm_vcpu_add(vm, 1, sender_guest_code);
+
+	test_data_page_vaddr = vm_vaddr_alloc_page(vm);
+	data = addr_gva2hva(vm, test_data_page_vaddr);
+	memset(data, 0, sizeof(*data));
+	params[0].data = data;
+	params[1].data = data;
+
+	vcpu_args_set(params[0].vcpu, 1, test_data_page_vaddr);
+	vcpu_args_set(params[1].vcpu, 1, test_data_page_vaddr);
+
+	pipis_rcvd = (uint64_t *)addr_gva2hva(vm, (uint64_t)&ipis_rcvd);
+	params[0].pipis_rcvd = pipis_rcvd;
+	params[1].pipis_rcvd = pipis_rcvd;
+
+	/* Start halter vCPU thread and wait for it to execute first HLT. */
+	r = pthread_create(&threads[0], NULL, vcpu_thread, &params[0]);
+	TEST_ASSERT(r == 0,
+		    "pthread_create halter failed errno=%d", errno);
+	fprintf(stderr, "Halter vCPU thread started\n");
+
+	wait_secs = 0;
+	while ((wait_secs < max_halter_wait) && !data->hlt_count) {
+		sleep(1);
+		wait_secs++;
+	}
+
+	TEST_ASSERT(data->hlt_count,
+		    "Halter vCPU did not execute first HLT within %d seconds",
+		    max_halter_wait);
+
+	fprintf(stderr,
+		"Halter vCPU thread reported its APIC ID: %u after %d seconds.\n",
+		data->halter_apic_id, wait_secs);
+
+	r = pthread_create(&threads[1], NULL, vcpu_thread, &params[1]);
+	TEST_ASSERT(r == 0, "pthread_create sender failed errno=%d", errno);
+
+	fprintf(stderr,
+		"IPI sender vCPU thread started. Letting vCPUs run for %d seconds.\n",
+		run_secs);
+
+	if (!migrate)
+		sleep(run_secs);
+	else
+		do_migrations(data, run_secs, delay_usecs, pipis_rcvd);
+
+	/*
+	 * Cancel threads and wait for them to stop.
+	 */
+	cancel_join_vcpu_thread(threads[0], params[0].vcpu);
+	cancel_join_vcpu_thread(threads[1], params[1].vcpu);
+
+	/*
+	 * If the host support Idle HLT, i.e. KVM *might* be using Idle HLT,
+	 * then the number of HLT exits may be less than the number of HLTs
+	 * that were executed, as Idle HLT elides the exit if the vCPU has an
+	 * unmasked, pending IRQ (or NMI).
+	 */
+	if (this_cpu_has(X86_FEATURE_IDLE_HLT))
+		TEST_ASSERT(data->hlt_count >= vcpu_get_stat(params[0].vcpu, halt_exits),
+			    "HLT insns = %lu, HLT exits = %lu",
+			    data->hlt_count, vcpu_get_stat(params[0].vcpu, halt_exits));
+	else
+		TEST_ASSERT_EQ(data->hlt_count, vcpu_get_stat(params[0].vcpu, halt_exits));
+
+	fprintf(stderr,
+		"Test successful after running for %d seconds.\n"
+		"Sending vCPU sent %lu IPIs to halting vCPU\n"
+		"Halting vCPU halted %lu times, woke %lu times, received %lu IPIs.\n"
+		"Halter APIC ID=%#x\n"
+		"Sender ICR value=%#x ICR2 value=%#x\n"
+		"Halter TPR=%#x PPR=%#x LVR=%#x\n"
+		"Migrations attempted: %lu\n"
+		"Migrations completed: %lu\n",
+		run_secs, data->ipis_sent,
+		data->hlt_count, data->wake_count, *pipis_rcvd,
+		data->halter_apic_id,
+		data->icr, data->icr2,
+		data->halter_tpr, data->halter_ppr, data->halter_lvr,
+		data->migrations_attempted, data->migrations_completed);
+
+	kvm_vm_free(vm);
+
+	return 0;
+}