Add an ioctl to assert and deassert an ioapic pin atomically. This will be used

to inject edge triggered legacy interrupts into the guest.

Start using the new API in device models that use edge triggered interrupts:
viz. the 8254 timer and the LPC/uart device emulation.

Submitted by:	Tycho Nightingale (tycho.nightingale@pluribusnetworks.com)

10 files changed, 67 insertions, 14 deletions

diff --git a/lib/libvmmapi/vmmapi.c b/lib/libvmmapi/vmmapi.c
index 5ece80b..85b1069 100644
--- a/lib/libvmmapi/vmmapi.c
+++ b/lib/libvmmapi/vmmapi.c
@@ -419,6 +419,17 @@ vm_ioapic_deassert_irq(struct vmctx *ctx, int irq)
 }
 
 int
+vm_ioapic_pulse_irq(struct vmctx *ctx, int irq)
+{
+	struct vm_ioapic_irq ioapic_irq;
+
+	bzero(&ioapic_irq, sizeof(struct vm_ioapic_irq));
+	ioapic_irq.irq = irq;
+
+	return (ioctl(ctx->fd, VM_IOAPIC_PULSE_IRQ, &ioapic_irq));
+}
+
+int
 vm_inject_nmi(struct vmctx *ctx, int vcpu)
 {
 	struct vm_nmi vmnmi;
diff --git a/lib/libvmmapi/vmmapi.h b/lib/libvmmapi/vmmapi.h
index c9a2a09..8eaea29 100644
--- a/lib/libvmmapi/vmmapi.h
+++ b/lib/libvmmapi/vmmapi.h
@@ -69,6 +69,7 @@ int	vm_inject_event2(struct vmctx *ctx, int vcpu, enum vm_event_type type,
 int	vm_lapic_irq(struct vmctx *ctx, int vcpu, int vector);
 int	vm_ioapic_assert_irq(struct vmctx *ctx, int irq);
 int	vm_ioapic_deassert_irq(struct vmctx *ctx, int irq);
+int	vm_ioapic_pulse_irq(struct vmctx *ctx, int irq);
 int	vm_inject_nmi(struct vmctx *ctx, int vcpu);
 int	vm_capability_name2type(const char *capname);
 const char *vm_capability_type2name(int type);
diff --git a/sys/amd64/include/vmm_dev.h b/sys/amd64/include/vmm_dev.h
index 2adf50d..cd4332b 100644
--- a/sys/amd64/include/vmm_dev.h
+++ b/sys/amd64/include/vmm_dev.h
@@ -170,6 +170,7 @@ enum {
 	IOCNUM_INJECT_NMI = 32,
 	IOCNUM_IOAPIC_ASSERT_IRQ = 33,
 	IOCNUM_IOAPIC_DEASSERT_IRQ = 34,
+	IOCNUM_IOAPIC_PULSE_IRQ = 35,
 
 	/* PCI pass-thru */
 	IOCNUM_BIND_PPTDEV = 40,
@@ -209,6 +210,8 @@ enum {
 	_IOW('v', IOCNUM_IOAPIC_ASSERT_IRQ, struct vm_ioapic_irq)
 #define	VM_IOAPIC_DEASSERT_IRQ	\
 	_IOW('v', IOCNUM_IOAPIC_DEASSERT_IRQ, struct vm_ioapic_irq)
+#define	VM_IOAPIC_PULSE_IRQ	\
+	_IOW('v', IOCNUM_IOAPIC_PULSE_IRQ, struct vm_ioapic_irq)
 #define	VM_SET_CAPABILITY \
 	_IOW('v', IOCNUM_SET_CAPABILITY, struct vm_capability)
 #define	VM_GET_CAPABILITY \
diff --git a/sys/amd64/vmm/io/vioapic.c b/sys/amd64/vmm/io/vioapic.c
index bc8485e..9ce8a5e 100644
--- a/sys/amd64/vmm/io/vioapic.c
+++ b/sys/amd64/vmm/io/vioapic.c
@@ -160,8 +160,14 @@ vioapic_set_pinstate(struct vioapic *vioapic, int pin, bool newstate)
 	}
 }
 
+enum irqstate {
+	IRQSTATE_ASSERT,
+	IRQSTATE_DEASSERT,
+	IRQSTATE_PULSE
+};
+
 static int
-vioapic_set_irqstate(struct vm *vm, int irq, bool state)
+vioapic_set_irqstate(struct vm *vm, int irq, enum irqstate irqstate)
 {
 	struct vioapic *vioapic;
 
@@ -171,7 +177,20 @@ vioapic_set_irqstate(struct vm *vm, int irq, bool state)
 	vioapic = vm_ioapic(vm);
 
 	VIOAPIC_LOCK(vioapic);
-	vioapic_set_pinstate(vioapic, irq, state);
+	switch (irqstate) {
+	case IRQSTATE_ASSERT:
+		vioapic_set_pinstate(vioapic, irq, true);
+		break;
+	case IRQSTATE_DEASSERT:
+		vioapic_set_pinstate(vioapic, irq, false);
+		break;
+	case IRQSTATE_PULSE:
+		vioapic_set_pinstate(vioapic, irq, true);
+		vioapic_set_pinstate(vioapic, irq, false);
+		break;
+	default:
+		panic("vioapic_set_irqstate: invalid irqstate %d", irqstate);
+	}
 	VIOAPIC_UNLOCK(vioapic);
 
 	return (0);
@@ -181,14 +200,21 @@ int
 vioapic_assert_irq(struct vm *vm, int irq)
 {
 
-	return (vioapic_set_irqstate(vm, irq, true));
+	return (vioapic_set_irqstate(vm, irq, IRQSTATE_ASSERT));
 }
 
 int
 vioapic_deassert_irq(struct vm *vm, int irq)
 {
 
-	return (vioapic_set_irqstate(vm, irq, false));
+	return (vioapic_set_irqstate(vm, irq, IRQSTATE_DEASSERT));
+}
+
+int
+vioapic_pulse_irq(struct vm *vm, int irq)
+{
+
+	return (vioapic_set_irqstate(vm, irq, IRQSTATE_PULSE));
 }
 
 static uint32_t
diff --git a/sys/amd64/vmm/io/vioapic.h b/sys/amd64/vmm/io/vioapic.h
index 54ad36a..3890250 100644
--- a/sys/amd64/vmm/io/vioapic.h
+++ b/sys/amd64/vmm/io/vioapic.h
@@ -41,6 +41,7 @@ void	vioapic_cleanup(struct vioapic *vioapic);
 
 int	vioapic_assert_irq(struct vm *vm, int irq);
 int	vioapic_deassert_irq(struct vm *vm, int irq);
+int	vioapic_pulse_irq(struct vm *vm, int irq);
 
 int	vioapic_mmio_write(void *vm, int vcpuid, uint64_t gpa,
 	    uint64_t wval, int size, void *arg);
diff --git a/sys/amd64/vmm/vmm_dev.c b/sys/amd64/vmm/vmm_dev.c
index a639ce9..500ef41 100644
--- a/sys/amd64/vmm/vmm_dev.c
+++ b/sys/amd64/vmm/vmm_dev.c
@@ -303,6 +303,10 @@ vmmdev_ioctl(struct cdev *cdev, u_long cmd, caddr_t data, int fflag,
 		ioapic_irq = (struct vm_ioapic_irq *)data;
 		error = vioapic_deassert_irq(sc->vm, ioapic_irq->irq);
 		break;
+	case VM_IOAPIC_PULSE_IRQ:
+		ioapic_irq = (struct vm_ioapic_irq *)data;
+		error = vioapic_pulse_irq(sc->vm, ioapic_irq->irq);
+		break;
 	case VM_MAP_MEMORY:
 		seg = (struct vm_memory_segment *)data;
 		error = vm_malloc(sc->vm, seg->gpa, seg->len);
diff --git a/usr.sbin/bhyve/pci_emul.c b/usr.sbin/bhyve/pci_emul.c
index fd087fa..c7086dd 100644
--- a/usr.sbin/bhyve/pci_emul.c
+++ b/usr.sbin/bhyve/pci_emul.c
@@ -1135,7 +1135,11 @@ pci_lintr_assert(struct pci_devinst *pi)
 {
 
 	assert(pi->pi_lintr_pin >= 0);
-	vm_ioapic_assert_irq(pi->pi_vmctx, pi->pi_lintr_pin);
+
+	if (pi->pi_lintr_state == 0) {
+		pi->pi_lintr_state = 1;
+		vm_ioapic_assert_irq(pi->pi_vmctx, pi->pi_lintr_pin);
+	}
 }
 
 void
@@ -1143,7 +1147,11 @@ pci_lintr_deassert(struct pci_devinst *pi)
 {
 
 	assert(pi->pi_lintr_pin >= 0);
-	vm_ioapic_deassert_irq(pi->pi_vmctx, pi->pi_lintr_pin);
+
+	if (pi->pi_lintr_state == 1) {
+		pi->pi_lintr_state = 0;
+		vm_ioapic_deassert_irq(pi->pi_vmctx, pi->pi_lintr_pin);
+	}
 }
 
 /*
diff --git a/usr.sbin/bhyve/pci_emul.h b/usr.sbin/bhyve/pci_emul.h
index ebcf834..6a1d757 100644
--- a/usr.sbin/bhyve/pci_emul.h
+++ b/usr.sbin/bhyve/pci_emul.h
@@ -104,6 +104,7 @@ struct pci_devinst {
 	struct vmctx *pi_vmctx;
 	uint8_t	  pi_bus, pi_slot, pi_func;
 	int8_t    pi_lintr_pin;
+	int8_t	  pi_lintr_state;
 	char	  pi_name[PI_NAMESZ];
 	int	  pi_bar_getsize;
 
diff --git a/usr.sbin/bhyve/pci_lpc.c b/usr.sbin/bhyve/pci_lpc.c
index 5dc79e0..4157c5c 100644
--- a/usr.sbin/bhyve/pci_lpc.c
+++ b/usr.sbin/bhyve/pci_lpc.c
@@ -94,17 +94,16 @@ lpc_uart_intr_assert(void *arg)
 
 	assert(sc->irq >= 0);
 
-	vm_ioapic_assert_irq(lpc_bridge->pi_vmctx, sc->irq);
+	vm_ioapic_pulse_irq(lpc_bridge->pi_vmctx, sc->irq);
 }
 
 static void
 lpc_uart_intr_deassert(void *arg)
 {
-	struct lpc_uart_softc *sc = arg;
-
-	assert(sc->irq >= 0);
-
-	vm_ioapic_deassert_irq(lpc_bridge->pi_vmctx, sc->irq);
+	/* 
+	 * The COM devices on the LPC bus generate edge triggered interrupts,
+	 * so nothing more to do here.
+	 */
 }
 
 static int
diff --git a/usr.sbin/bhyve/pit_8254.c b/usr.sbin/bhyve/pit_8254.c
index fd05b00..9ecb565 100644
--- a/usr.sbin/bhyve/pit_8254.c
+++ b/usr.sbin/bhyve/pit_8254.c
@@ -105,8 +105,7 @@ pit_mevent_cb(int fd, enum ev_type type, void *param)
 
 	pit_mev_count++;
 
-	vm_ioapic_assert_irq(c->ctx, 2);
-	vm_ioapic_deassert_irq(c->ctx, 2);
+	vm_ioapic_pulse_irq(c->ctx, 2);
 
 	/*
 	 * Delete the timer for one-shots