[PATCH kvmtool 2/9] vfio: Factor out wired IRQ setup and teardown

[Mostafa Saleh <smostafa@google.com>]

Factor the wired IRQ eventfd and KVM irqfd setup and teardown out of
vfio_pci_enable_intx() and vfio_pci_disable_intx() into
vfio_irq_enable() and vfio_irq_disable() in vfio/core.c, and move
union vfio_irq_eventfd to vfio.h so both PCI INTx and VFIO platform
devices can share them.

The is a mechanical code move, no functional change.

Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
 include/kvm/vfio.h |  27 +++++++++--
 vfio/core.c        | 107 +++++++++++++++++++++++++++++++++++++++++++
 vfio/pci.c         | 110 +++------------------------------------------
 3 files changed, 137 insertions(+), 107 deletions(-)

diff --git a/include/kvm/vfio.h b/include/kvm/vfio.h
index ac7b622..9a5783e 100644
--- a/include/kvm/vfio.h
+++ b/include/kvm/vfio.h
@@ -6,6 +6,7 @@
 #include "kvm/pci.h"
 
 #include <linux/vfio.h>
+#include <string.h>
 
 #define vfio_dev_err(vdev, fmt, ...) \
 	pr_err("%s: " fmt, (vdev)->params->name, ##__VA_ARGS__)
@@ -70,13 +71,17 @@ struct vfio_pci_msi_common {
 #define VFIO_PCI_IRQ_MODE_MSI		(1 << 1)
 #define VFIO_PCI_IRQ_MODE_MSIX		(1 << 2)
 
+struct vfio_irq {
+	int				gsi;
+	int				trigger_fd;
+	int				unmask_fd;
+};
+
 struct vfio_pci_device {
 	struct pci_device_header	hdr;
 
 	unsigned long			irq_modes;
-	int				intx_fd;
-	int				unmask_fd;
-	unsigned int			intx_gsi;
+	struct vfio_irq			intx;
 	struct vfio_pci_msi_common	msi;
 	struct vfio_pci_msi_common	msix;
 	struct vfio_pci_msix_table	msix_table;
@@ -119,10 +124,26 @@ struct vfio_group {
 	struct list_head		list;
 };
 
+/* Wrapper around UAPI vfio_irq_set */
+union vfio_irq_eventfd {
+	struct vfio_irq_set	irq;
+	u8 buffer[sizeof(struct vfio_irq_set) + sizeof(int)];
+};
+
+static inline void set_vfio_irq_eventd_payload(union vfio_irq_eventfd *evfd,
+					       int fd)
+{
+	memcpy(&evfd->irq.data, &fd, sizeof(fd));
+}
+
 int vfio_device_parser(const struct option *opt, const char *arg, int unset);
 int vfio_map_region(struct kvm *kvm, struct vfio_device *vdev,
 		    struct vfio_region *region);
 void vfio_unmap_region(struct kvm *kvm, struct vfio_region *region);
+int vfio_irq_enable(struct kvm *kvm, struct vfio_device *vdev,
+		    unsigned int index, struct vfio_irq *irq);
+void vfio_irq_disable(struct kvm *kvm, struct vfio_device *vdev,
+		      unsigned int index, struct vfio_irq *irq);
 int vfio_pci_setup_device(struct kvm *kvm, struct vfio_device *device);
 void vfio_pci_teardown_device(struct kvm *kvm, struct vfio_device *vdev);
 
diff --git a/vfio/core.c b/vfio/core.c
index e0c56ab..24d3f2d 100644
--- a/vfio/core.c
+++ b/vfio/core.c
@@ -1,8 +1,10 @@
+#include "kvm/irq.h"
 #include "kvm/kvm.h"
 #include "kvm/vfio.h"
 #include "kvm/ioport.h"
 
 #include <linux/list.h>
+#include <sys/eventfd.h>
 #include <libgen.h>
 
 #define VFIO_DEV_DIR		"/dev/vfio"
@@ -282,6 +284,111 @@ void vfio_unmap_region(struct kvm *kvm, struct vfio_region *region)
 	}
 }
 
+void vfio_irq_disable(struct kvm *kvm, struct vfio_device *vdev,
+		      unsigned int index, struct vfio_irq *irq)
+{
+	int gsi = irq->gsi;
+	struct vfio_irq_set irq_set = {
+		.argsz	= sizeof(irq_set),
+		.flags	= VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_TRIGGER,
+		.index	= index,
+	};
+
+	if (irq->trigger_fd == -1)
+		return;
+
+	ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, &irq_set);
+	irq__del_irqfd(kvm, gsi, irq->trigger_fd);
+
+	close(irq->trigger_fd);
+	close(irq->unmask_fd);
+	irq->trigger_fd = -1;
+}
+
+int vfio_irq_enable(struct kvm *kvm, struct vfio_device *vdev,
+		    unsigned int index, struct vfio_irq *irq)
+{
+	int ret;
+	int trigger_fd, unmask_fd;
+	union vfio_irq_eventfd	trigger;
+	union vfio_irq_eventfd	unmask;
+	int gsi = irq->gsi;
+
+	if (irq->trigger_fd != -1)
+		return 0;
+
+	/*
+	 * PCI IRQ is level-triggered, so we use two eventfds. trigger_fd
+	 * signals an interrupt from host to guest, and unmask_fd signals the
+	 * deassertion of the line from guest to host.
+	 */
+	trigger_fd = eventfd(0, 0);
+	if (trigger_fd < 0) {
+		vfio_dev_err(vdev, "failed to create trigger eventfd");
+		return trigger_fd;
+	}
+
+	unmask_fd = eventfd(0, 0);
+	if (unmask_fd < 0) {
+		vfio_dev_err(vdev, "failed to create unmask eventfd");
+		close(trigger_fd);
+		return unmask_fd;
+	}
+
+	ret = irq__add_irqfd(kvm, gsi, trigger_fd, unmask_fd);
+	if (ret)
+		goto err_close;
+
+	trigger.irq = (struct vfio_irq_set) {
+		.argsz	= sizeof(trigger),
+		.flags	= VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER,
+		.index	= index,
+		.start	= 0,
+		.count	= 1,
+	};
+	set_vfio_irq_eventd_payload(&trigger, trigger_fd);
+
+	ret = ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, &trigger);
+	if (ret < 0) {
+		vfio_dev_err(vdev, "failed to setup VFIO IRQ");
+		goto err_delete_line;
+	}
+
+	unmask.irq = (struct vfio_irq_set) {
+		.argsz	= sizeof(unmask),
+		.flags	= VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_UNMASK,
+		.index	= index,
+		.start	= 0,
+		.count	= 1,
+	};
+	set_vfio_irq_eventd_payload(&unmask, unmask_fd);
+
+	ret = ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, &unmask);
+	if (ret < 0) {
+		vfio_dev_err(vdev, "failed to setup unmask IRQ");
+		goto err_remove_event;
+	}
+
+	irq->trigger_fd = trigger_fd;
+	irq->unmask_fd = unmask_fd;
+
+	return 0;
+
+err_remove_event:
+	/* Remove trigger event */
+	trigger.irq.flags = VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_TRIGGER;
+	trigger.irq.count = 0;
+	ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, &trigger);
+
+err_delete_line:
+	irq__del_irqfd(kvm, gsi, trigger_fd);
+
+err_close:
+	close(trigger_fd);
+	close(unmask_fd);
+	return ret;
+}
+
 static int vfio_configure_device(struct kvm *kvm, struct vfio_device *vdev)
 {
 	int ret;
diff --git a/vfio/pci.c b/vfio/pci.c
index 0bcd60e..fb98435 100644
--- a/vfio/pci.c
+++ b/vfio/pci.c
@@ -17,17 +17,6 @@
 #define PCI_CAP_EXP_RC_ENDPOINT_SIZEOF_V1	12
 #endif
 
-/* Wrapper around UAPI vfio_irq_set */
-union vfio_irq_eventfd {
-	struct vfio_irq_set	irq;
-	u8 buffer[sizeof(struct vfio_irq_set) + sizeof(int)];
-};
-
-static void set_vfio_irq_eventd_payload(union vfio_irq_eventfd *evfd, int fd)
-{
-	memcpy(&evfd->irq.data, &fd, sizeof(fd));
-}
-
 /*
  * To support MSI and MSI-X with common code, track the host and guest states of
  * the MSI/MSI-X capability, and of individual vectors.
@@ -1213,108 +1202,21 @@ static int vfio_pci_init_msis(struct kvm *kvm, struct vfio_device *vdev,
 static void vfio_pci_disable_intx(struct kvm *kvm, struct vfio_device *vdev)
 {
 	struct vfio_pci_device *pdev = &vdev->pci;
-	int gsi = pdev->intx_gsi;
-	struct vfio_irq_set irq_set = {
-		.argsz	= sizeof(irq_set),
-		.flags	= VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_TRIGGER,
-		.index	= VFIO_PCI_INTX_IRQ_INDEX,
-	};
+	int gsi = pdev->intx.gsi;
 
-	if (pdev->intx_fd == -1)
+	if (pdev->intx.trigger_fd == -1)
 		return;
 
 	pr_debug("user requested MSI, disabling INTx %d", gsi);
 
-	ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, &irq_set);
-	irq__del_irqfd(kvm, gsi, pdev->intx_fd);
-
-	close(pdev->intx_fd);
-	close(pdev->unmask_fd);
-	pdev->intx_fd = -1;
+	vfio_irq_disable(kvm, vdev, VFIO_PCI_INTX_IRQ_INDEX, &pdev->intx);
 }
 
 static int vfio_pci_enable_intx(struct kvm *kvm, struct vfio_device *vdev)
 {
-	int ret;
-	int trigger_fd, unmask_fd;
-	union vfio_irq_eventfd	trigger;
-	union vfio_irq_eventfd	unmask;
 	struct vfio_pci_device *pdev = &vdev->pci;
-	int gsi = pdev->intx_gsi;
 
-	if (pdev->intx_fd != -1)
-		return 0;
-
-	/*
-	 * PCI IRQ is level-triggered, so we use two eventfds. trigger_fd
-	 * signals an interrupt from host to guest, and unmask_fd signals the
-	 * deassertion of the line from guest to host.
-	 */
-	trigger_fd = eventfd(0, 0);
-	if (trigger_fd < 0) {
-		vfio_dev_err(vdev, "failed to create trigger eventfd");
-		return trigger_fd;
-	}
-
-	unmask_fd = eventfd(0, 0);
-	if (unmask_fd < 0) {
-		vfio_dev_err(vdev, "failed to create unmask eventfd");
-		close(trigger_fd);
-		return unmask_fd;
-	}
-
-	ret = irq__add_irqfd(kvm, gsi, trigger_fd, unmask_fd);
-	if (ret)
-		goto err_close;
-
-	trigger.irq = (struct vfio_irq_set) {
-		.argsz	= sizeof(trigger),
-		.flags	= VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER,
-		.index	= VFIO_PCI_INTX_IRQ_INDEX,
-		.start	= 0,
-		.count	= 1,
-	};
-	set_vfio_irq_eventd_payload(&trigger, trigger_fd);
-
-	ret = ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, &trigger);
-	if (ret < 0) {
-		vfio_dev_err(vdev, "failed to setup VFIO IRQ");
-		goto err_delete_line;
-	}
-
-	unmask.irq = (struct vfio_irq_set) {
-		.argsz	= sizeof(unmask),
-		.flags	= VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_UNMASK,
-		.index	= VFIO_PCI_INTX_IRQ_INDEX,
-		.start	= 0,
-		.count	= 1,
-	};
-	set_vfio_irq_eventd_payload(&unmask, unmask_fd);
-
-	ret = ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, &unmask);
-	if (ret < 0) {
-		vfio_dev_err(vdev, "failed to setup unmask IRQ");
-		goto err_remove_event;
-	}
-
-	pdev->intx_fd = trigger_fd;
-	pdev->unmask_fd = unmask_fd;
-
-	return 0;
-
-err_remove_event:
-	/* Remove trigger event */
-	trigger.irq.flags = VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_TRIGGER;
-	trigger.irq.count = 0;
-	ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, &trigger);
-
-err_delete_line:
-	irq__del_irqfd(kvm, gsi, trigger_fd);
-
-err_close:
-	close(trigger_fd);
-	close(unmask_fd);
-	return ret;
+	return vfio_irq_enable(kvm, vdev, VFIO_PCI_INTX_IRQ_INDEX, &pdev->intx);
 }
 
 static int vfio_pci_init_intx(struct kvm *kvm, struct vfio_device *vdev)
@@ -1345,9 +1247,9 @@ static int vfio_pci_init_intx(struct kvm *kvm, struct vfio_device *vdev)
 	}
 
 	/* Guest is going to ovewrite our irq_line... */
-	pdev->intx_gsi = pdev->hdr.irq_line - KVM_IRQ_OFFSET;
+	pdev->intx.gsi = pdev->hdr.irq_line - KVM_IRQ_OFFSET;
 
-	pdev->intx_fd = -1;
+	pdev->intx.trigger_fd = -1;
 
 	return 0;
 }
-- 
2.56.0.307.g5fe7bd680c-goog