KVM: selftests: aarch64: Add vgic_irq to test userspace IRQ injection

Add a new KVM selftest, vgic_irq, for testing userspace IRQ injection.  This
particular test injects an SPI using KVM_IRQ_LINE on GICv3 and verifies
that the IRQ is handled in the guest. The next commits will add more
types of IRQs and different modes.

Signed-off-by: Ricardo Koller <ricarkol@google.com>
Acked-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211109023906.1091208-7-ricarkol@google.com

tools/testing/selftests/kvm/.gitignore

@@ -4,6 +4,7 @@
 /aarch64/get-reg-list
 /aarch64/psci_cpu_on_test
 /aarch64/vgic_init
+/aarch64/vgic_irq
 /s390x/memop
 /s390x/resets
 /s390x/sync_regs_test

tools/testing/selftests/kvm/Makefile

@@ -94,6 +94,7 @@ TEST_GEN_PROGS_aarch64 += aarch64/debug-exceptions
 TEST_GEN_PROGS_aarch64 += aarch64/get-reg-list
 TEST_GEN_PROGS_aarch64 += aarch64/psci_cpu_on_test
 TEST_GEN_PROGS_aarch64 += aarch64/vgic_init
+TEST_GEN_PROGS_aarch64 += aarch64/vgic_irq
 TEST_GEN_PROGS_aarch64 += demand_paging_test
 TEST_GEN_PROGS_aarch64 += dirty_log_test
 TEST_GEN_PROGS_aarch64 += dirty_log_perf_test

tools/testing/selftests/kvm/aarch64/vgic_irq.c

@@ -0,0 +1,244 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * vgic_irq.c - Test userspace injection of IRQs
+ *
+ * This test validates the injection of IRQs from userspace using various
+ * methods (e.g., KVM_IRQ_LINE) and modes (e.g., EOI). The guest "asks" the
+ * host to inject a specific intid via a GUEST_SYNC call, and then checks that
+ * it received it.
+ */
+
+#include <asm/kvm.h>
+#include <asm/kvm_para.h>
+#include <linux/sizes.h>
+
+#include "processor.h"
+#include "test_util.h"
+#include "kvm_util.h"
+#include "gic.h"
+#include "gic_v3.h"
+#include "vgic.h"
+
+#define GICD_BASE_GPA		0x08000000ULL
+#define GICR_BASE_GPA		0x080A0000ULL
+#define VCPU_ID			0
+
+/*
+ * KVM implements 32 priority levels:
+ * 0x00 (highest priority) - 0xF8 (lowest priority), in steps of 8
+ *
+ * Note that these macros will still be correct in the case that KVM implements
+ * more priority levels. Also note that 32 is the minimum for GICv3 and GICv2.
+ */
+#define KVM_NUM_PRIOS		32
+#define KVM_PRIO_SHIFT		3 /* steps of 8 = 1 << 3 */
+#define LOWEST_PRIO		(KVM_NUM_PRIOS - 1)
+#define CPU_PRIO_MASK		(LOWEST_PRIO << KVM_PRIO_SHIFT)	/* 0xf8 */
+#define IRQ_DEFAULT_PRIO	(LOWEST_PRIO - 1)
+#define IRQ_DEFAULT_PRIO_REG	(IRQ_DEFAULT_PRIO << KVM_PRIO_SHIFT) /* 0xf0 */
+
+static void *dist = (void *)GICD_BASE_GPA;
+static void *redist = (void *)GICR_BASE_GPA;
+
+/*
+ * The kvm_inject_* utilities are used by the guest to ask the host to inject
+ * interrupts (e.g., using the KVM_IRQ_LINE ioctl).
+ */
+
+typedef enum {
+	KVM_INJECT_EDGE_IRQ_LINE = 1,
+} kvm_inject_cmd;
+
+struct kvm_inject_args {
+	kvm_inject_cmd cmd;
+	uint32_t intid;
+};
+
+/* Used on the guest side to perform the hypercall. */
+static void kvm_inject_call(kvm_inject_cmd cmd, uint32_t intid);
+
+/* Used on the host side to get the hypercall info. */
+static void kvm_inject_get_call(struct kvm_vm *vm, struct ucall *uc,
+		struct kvm_inject_args *args);
+
+/* Shared between the guest main thread and the IRQ handlers. */
+volatile uint64_t irq_handled;
+volatile uint32_t irqnr_received[MAX_SPI + 1];
+
+static void reset_stats(void)
+{
+	int i;
+
+	irq_handled = 0;
+	for (i = 0; i <= MAX_SPI; i++)
+		irqnr_received[i] = 0;
+}
+
+static uint64_t gic_read_ap1r0(void)
+{
+	uint64_t reg = read_sysreg_s(SYS_ICV_AP1R0_EL1);
+
+	dsb(sy);
+	return reg;
+}
+
+static void guest_irq_handler(struct ex_regs *regs)
+{
+	uint32_t intid = gic_get_and_ack_irq();
+
+	if (intid == IAR_SPURIOUS)
+		return;
+
+	GUEST_ASSERT(gic_irq_get_active(intid));
+
+	GUEST_ASSERT(!gic_irq_get_pending(intid));
+
+	GUEST_ASSERT(intid < MAX_SPI);
+	irqnr_received[intid] += 1;
+	irq_handled += 1;
+
+	gic_set_eoi(intid);
+	GUEST_ASSERT_EQ(gic_read_ap1r0(), 0);
+
+	GUEST_ASSERT(!gic_irq_get_active(intid));
+	GUEST_ASSERT(!gic_irq_get_pending(intid));
+}
+
+static void kvm_inject_call(kvm_inject_cmd cmd, uint32_t intid)
+{
+	struct kvm_inject_args args = {
+		.cmd = cmd,
+		.intid = intid,
+	};
+	GUEST_SYNC(&args);
+}
+
+#define GUEST_ASSERT_IAR_EMPTY()						\
+do { 										\
+	uint32_t _intid;							\
+	_intid = gic_get_and_ack_irq();						\
+	GUEST_ASSERT(_intid == 0 || _intid == IAR_SPURIOUS);			\
+} while (0)
+
+static void test_kvm_irq_line(uint32_t intid)
+{
+	reset_stats();
+
+	asm volatile("msr daifset, #2" : : : "memory");
+	kvm_inject_call(KVM_INJECT_EDGE_IRQ_LINE, intid);
+
+	while (irq_handled < 1) {
+		asm volatile("wfi\n"
+			     "msr daifclr, #2\n"
+			     /* handle IRQ */
+			     "msr daifset, #2\n"
+			     : : : "memory");
+	}
+	asm volatile("msr daifclr, #2" : : : "memory");
+
+	GUEST_ASSERT_EQ(irq_handled, 1);
+	GUEST_ASSERT_EQ(irqnr_received[intid], 1);
+	GUEST_ASSERT_IAR_EMPTY();
+}
+
+static void guest_code(void)
+{
+	uint32_t i;
+	uint32_t nr_irqs = 64; /* absolute minimum number of IRQs supported. */
+
+	gic_init(GIC_V3, 1, dist, redist);
+
+	for (i = 0; i < nr_irqs; i++) {
+		gic_irq_enable(i);
+		gic_set_priority(i, IRQ_DEFAULT_PRIO_REG);
+	}
+
+	gic_set_priority_mask(CPU_PRIO_MASK);
+
+	local_irq_enable();
+
+	test_kvm_irq_line(MIN_SPI);
+
+	GUEST_DONE();
+}
+
+static void run_guest_cmd(struct kvm_vm *vm, int gic_fd,
+		struct kvm_inject_args *inject_args)
+{
+	kvm_inject_cmd cmd = inject_args->cmd;
+	uint32_t intid = inject_args->intid;
+
+	switch (cmd) {
+	case KVM_INJECT_EDGE_IRQ_LINE:
+		kvm_arm_irq_line(vm, intid, 1);
+		kvm_arm_irq_line(vm, intid, 0);
+		break;
+	default:
+		break;
+	}
+}
+
+static void kvm_inject_get_call(struct kvm_vm *vm, struct ucall *uc,
+		struct kvm_inject_args *args)
+{
+	struct kvm_inject_args *kvm_args_hva;
+	vm_vaddr_t kvm_args_gva;
+
+	kvm_args_gva = uc->args[1];
+	kvm_args_hva = (struct kvm_inject_args *)addr_gva2hva(vm, kvm_args_gva);
+	memcpy(args, kvm_args_hva, sizeof(struct kvm_inject_args));
+}
+
+
+static void test_vgic(void)
+{
+	struct ucall uc;
+	int gic_fd;
+	struct kvm_vm *vm;
+	struct kvm_inject_args inject_args;
+
+	vm = vm_create_default(VCPU_ID, 0, guest_code);
+	ucall_init(vm, NULL);
+
+	vm_init_descriptor_tables(vm);
+	vcpu_init_descriptor_tables(vm, VCPU_ID);
+
+	gic_fd = vgic_v3_setup(vm, 1, GICD_BASE_GPA, GICR_BASE_GPA);
+
+	vm_install_exception_handler(vm, VECTOR_IRQ_CURRENT,
+			guest_irq_handler);
+
+	while (1) {
+		vcpu_run(vm, VCPU_ID);
+
+		switch (get_ucall(vm, VCPU_ID, &uc)) {
+		case UCALL_SYNC:
+			kvm_inject_get_call(vm, &uc, &inject_args);
+			run_guest_cmd(vm, gic_fd, &inject_args);
+			break;
+		case UCALL_ABORT:
+			TEST_FAIL("%s at %s:%ld\n\tvalues: %#lx, %#lx",
+					(const char *)uc.args[0],
+					__FILE__, uc.args[1], uc.args[2], uc.args[3]);
+			break;
+		case UCALL_DONE:
+			goto done;
+		default:
+			TEST_FAIL("Unknown ucall %lu", uc.cmd);
+		}
+	}
+
+done:
+	close(gic_fd);
+	kvm_vm_free(vm);
+}
+
+int main(int ac, char **av)
+{
+	/* Tell stdout not to buffer its content */
+	setbuf(stdout, NULL);
+
+	test_vgic();
+
+	return 0;
+}