On 11/05/2014 11:29 AM, Alexander Graf wrote:
>
>
> On 31.10.14 15:05, Eric Auger wrote:
>> Minimal VFIO platform implementation supporting
>> - register space user mapping,
>> - IRQ assignment based on eventfds handled on qemu side.
>>
>> irqfd kernel acceleration comes in a subsequent patch.
>>
>> Signed-off-by: Kim Phillips <kim.phillips@xxxxxxxxxx>
>> Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
>>
>> ---
>> v6 -> v7:
>> - compat is not exposed anymore as a user option. Rationale is
>> the vfio device became abstract and a specialization is needed
>> anyway. The derived device must set the compat string.
>> - in v6 vfio_start_irq_injection was exposed in vfio-platform.h.
>> A new function dubbed vfio_register_irq_starter replaces it. It
>> registers a machine init done notifier that programs & starts
>> all dynamic VFIO device IRQs. This function is supposed to be
>> called by the machine file. A set of static helper routines are
>> added too. It must be called before the creation of the platform
>> bus device.
>>
>> v5 -> v6:
>> - vfio_device property renamed into host property
>> - correct error handling of VFIO_DEVICE_GET_IRQ_INFO ioctl
>> and remove PCI related comment
>> - remove declaration of vfio_setup_irqfd and irqfd_allowed
>> property.Both belong to next patch (irqfd)
>> - remove declaration of vfio_intp_interrupt in vfio-platform.h
>> - functions that can be static get this characteristic
>> - remove declarations of vfio_region_ops, vfio_memory_listener,
>> group_list, vfio_address_spaces. All are moved to vfio-common.h
>> - remove vfio_put_device declaration and definition
>> - print_regions removed. code moved into vfio_populate_regions
>> - replace DPRINTF by trace events
>> - new helper routine to set the trigger eventfd
>> - dissociate intp init from the injection enablement:
>> vfio_enable_intp renamed into vfio_init_intp and new function
>> named vfio_start_eventfd_injection
>> - injection start moved to vfio_start_irq_injection (not anymore
>> in vfio_populate_interrupt)
>> - new start_irq_fn field in VFIOPlatformDevice corresponding to
>> the function that will be used for starting injection
>> - user handled eventfd:
>> x add mutex to protect IRQ state & list manipulation,
>> x correct misleading comment in vfio_intp_interrupt.
>> x Fix bugs thanks to fake interrupt modality
>> - VFIOPlatformDeviceClass becomes abstract
>> - add error_setg in vfio_platform_realize
>>
>> v4 -> v5:
>> - vfio-plaform.h included first
>> - cleanup error handling in *populate*, vfio_get_device,
>> vfio_enable_intp
>> - vfio_put_device not called anymore
>> - add some includes to follow vfio policy
>>
>> v3 -> v4:
>> [Eric Auger]
>> - merge of "vfio: Add initial IRQ support in platform device"
>> to get a full functional patch although perfs are limited.
>> - removal of unrealize function since I currently understand
>> it is only used with device hot-plug feature.
>>
>> v2 -> v3:
>> [Eric Auger]
>> - further factorization between PCI and platform (VFIORegion,
>> VFIODevice). same level of functionality.
>>
>> <= v2:
>> [Kim Philipps]
>> - Initial Creation of the device supporting register space mapping
>> ---
>> hw/vfio/Makefile.objs | 1 +
>> hw/vfio/platform.c | 672 ++++++++++++++++++++++++++++++++++++++++
>> include/hw/vfio/vfio-common.h | 1 +
>> include/hw/vfio/vfio-platform.h | 87 ++++++
>> trace-events | 12 +
>> 5 files changed, 773 insertions(+)
>> create mode 100644 hw/vfio/platform.c
>> create mode 100644 include/hw/vfio/vfio-platform.h
>>
>> diff --git a/hw/vfio/Makefile.objs b/hw/vfio/Makefile.objs
>> index e31f30e..c5c76fe 100644
>> --- a/hw/vfio/Makefile.objs
>> +++ b/hw/vfio/Makefile.objs
>> @@ -1,4 +1,5 @@
>> ifeq ($(CONFIG_LINUX), y)
>> obj-$(CONFIG_SOFTMMU) += common.o
>> obj-$(CONFIG_PCI) += pci.o
>> +obj-$(CONFIG_SOFTMMU) += platform.o
>> endif
>> diff --git a/hw/vfio/platform.c b/hw/vfio/platform.c
>> new file mode 100644
>> index 0000000..9f66610
>> --- /dev/null
>> +++ b/hw/vfio/platform.c
>> @@ -0,0 +1,672 @@
>> +/*
>> + * vfio based device assignment support - platform devices
>> + *
>> + * Copyright Linaro Limited, 2014
>> + *
>> + * Authors:
>> + * Kim Phillips <kim.phillips@xxxxxxxxxx>
>> + *
>> + * This work is licensed under the terms of the GNU GPL, version 2. See
>> + * the COPYING file in the top-level directory.
>> + *
>> + * Based on vfio based PCI device assignment support:
>> + * Copyright Red Hat, Inc. 2012
>> + */
>> +
>> +#include <linux/vfio.h>
>> +#include <sys/ioctl.h>
>> +
>> +#include "hw/vfio/vfio-platform.h"
>> +#include "qemu/error-report.h"
>> +#include "qemu/range.h"
>> +#include "sysemu/sysemu.h"
>> +#include "exec/memory.h"
>> +#include "qemu/queue.h"
>> +#include "hw/sysbus.h"
>> +#include "trace.h"
>> +#include "hw/platform-bus.h"
>> +
>> +static void vfio_intp_interrupt(VFIOINTp *intp);
>> +typedef void (*eventfd_user_side_handler_t)(VFIOINTp *intp);
>> +static int vfio_set_trigger_eventfd(VFIOINTp *intp,
>> + eventfd_user_side_handler_t handler);
>> +
>> +/*
>> + * Functions only used when eventfd are handled on user-side
>> + * ie. without irqfd
>> + */
>> +
>> +/**
>> + * vfio_platform_eoi - IRQ completion routine
>> + * @vbasedev: the VFIO device
>> + *
>> + * de-asserts the active virtual IRQ and unmask the physical IRQ
>> + * (masked by the VFIO driver). Handle pending IRQs if any.
>> + * eoi function is called on the first access to any MMIO region
>> + * after an IRQ was triggered. It is assumed this access corresponds
>> + * to the IRQ status register reset. With such a mechanism, a single
>> + * IRQ can be handled at a time since there is no way to know which
>> + * IRQ was completed by the guest (we would need additional details
>> + * about the IRQ status register mask)
>> + */
>> +static void vfio_platform_eoi(VFIODevice *vbasedev)
>> +{
>> + VFIOINTp *intp;
>> + VFIOPlatformDevice *vdev =
>> + container_of(vbasedev, VFIOPlatformDevice, vbasedev);
>> +
>> + qemu_mutex_lock(&vdev->intp_mutex);
>> + QLIST_FOREACH(intp, &vdev->intp_list, next) {
>> + if (intp->state == VFIO_IRQ_ACTIVE) {
>> + trace_vfio_platform_eoi(intp->pin,
>> + event_notifier_get_fd(&intp->interrupt));
>> + intp->state = VFIO_IRQ_INACTIVE;
>> +
>> + /* deassert the virtual IRQ and unmask physical one */
>> + qemu_set_irq(intp->qemuirq, 0);
>> + vfio_unmask_irqindex(vbasedev, intp->pin);
>> +
>> + /* a single IRQ can be active at a time */
>> + break;
>> + }
>> + }
>> + /* in case there are pending IRQs, handle them one at a time */
>> + if (!QSIMPLEQ_EMPTY(&vdev->pending_intp_queue)) {
>> + intp = QSIMPLEQ_FIRST(&vdev->pending_intp_queue);
>> + trace_vfio_platform_eoi_handle_pending(intp->pin);
>> + qemu_mutex_unlock(&vdev->intp_mutex);
>> + vfio_intp_interrupt(intp);
>> + qemu_mutex_lock(&vdev->intp_mutex);
>> + QSIMPLEQ_REMOVE_HEAD(&vdev->pending_intp_queue, pqnext);
>> + qemu_mutex_unlock(&vdev->intp_mutex);
>> + } else {
>> + qemu_mutex_unlock(&vdev->intp_mutex);
>> + }
>> +}
>> +
>> +/**
>> + * vfio_mmap_set_enabled - enable/disable the fast path mode
>> + * @vdev: the VFIO platform device
>> + * @enabled: the target mmap state
>> + *
>> + * true ~ fast path = MMIO region is mmaped (no KVM TRAP)
>> + * false ~ slow path = MMIO region is trapped and region callbacks
>> + * are called slow path enables to trap the IRQ status register
>> + * guest reset
>> +*/
>> +
>> +static void vfio_mmap_set_enabled(VFIOPlatformDevice *vdev, bool enabled)
>> +{
>> + VFIORegion *region;
>> + int i;
>> +
>> + trace_vfio_platform_mmap_set_enabled(enabled);
>> +
>> + for (i = 0; i < vdev->vbasedev.num_regions; i++) {
>> + region = vdev->regions[i];
>> +
>> + /* register space is unmapped to trap EOI */
>> + memory_region_set_enabled(®ion->mmap_mem, enabled);
>> + }
>> +}
>> +
>> +/**
>> + * vfio_intp_mmap_enable - timer function, restores the fast path
>> + * if there is no more active IRQ
>> + * @opaque: actually points to the VFIO platform device
>> + *
>> + * Called on mmap timer timout, this function checks whether the
>> + * IRQ is still active and in the negative restores the fast path.
>> + * by construction a single eventfd is handled at a time.
>> + * if the IRQ is still active, the timer is restarted.
>> + */
>> +static void vfio_intp_mmap_enable(void *opaque)
>> +{
>> + VFIOINTp *tmp;
>> + VFIOPlatformDevice *vdev = (VFIOPlatformDevice *)opaque;
>> +
>> + qemu_mutex_lock(&vdev->intp_mutex);
>> + QLIST_FOREACH(tmp, &vdev->intp_list, next) {
>> + if (tmp->state == VFIO_IRQ_ACTIVE) {
>> + trace_vfio_platform_intp_mmap_enable(tmp->pin);
>> + /* re-program the timer to check active status later */
>> + timer_mod(vdev->mmap_timer,
>> + qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
>> + vdev->mmap_timeout);
>> + qemu_mutex_unlock(&vdev->intp_mutex);
>> + return;
>> + }
>> + }
>> + vfio_mmap_set_enabled(vdev, true);
>> + qemu_mutex_unlock(&vdev->intp_mutex);
>> +}
>> +
>> +/**
>> + * vfio_intp_interrupt - The user-side eventfd handler
>> + * @opaque: opaque pointer which in practice is the VFIOINTp*
>> + *
>> + * the function can be entered
>> + * - in event handler context: this IRQ is inactive
>> + * in that case, the vIRQ is injected into the guest if there
>> + * is no other active or pending IRQ.
>> + * - in IOhandler context: this IRQ is pending.
>> + * there is no ACTIVE IRQ
>> + */
>> +static void vfio_intp_interrupt(VFIOINTp *intp)
>> +{
>> + int ret;
>> + VFIOINTp *tmp;
>> + VFIOPlatformDevice *vdev = intp->vdev;
>> + bool delay_handling = false;
>> +
>> + qemu_mutex_lock(&vdev->intp_mutex);
>> + if (intp->state == VFIO_IRQ_INACTIVE) {
>> + QLIST_FOREACH(tmp, &vdev->intp_list, next) {
>> + if (tmp->state == VFIO_IRQ_ACTIVE ||
>> + tmp->state == VFIO_IRQ_PENDING) {
>> + delay_handling = true;
>> + break;
>> + }
>> + }
>> + }
>> + if (delay_handling) {
>> + /*
>> + * the new IRQ gets a pending status and is pushed in
>> + * the pending queue
>> + */
>> + intp->state = VFIO_IRQ_PENDING;
>> + trace_vfio_intp_interrupt_set_pending(intp->pin);
>> + QSIMPLEQ_INSERT_TAIL(&vdev->pending_intp_queue,
>> + intp, pqnext);
>> + ret = event_notifier_test_and_clear(&intp->interrupt);
>> + qemu_mutex_unlock(&vdev->intp_mutex);
>> + return;
>> + }
>> +
>> + /* no active IRQ, the new IRQ can be forwarded to the guest */
>> + trace_vfio_platform_intp_interrupt(intp->pin,
>> + event_notifier_get_fd(&intp->interrupt));
>> +
>> + if (intp->state == VFIO_IRQ_INACTIVE) {
>> + ret = event_notifier_test_and_clear(&intp->interrupt);
>> + if (!ret) {
>> + error_report("Error when clearing fd=%d (ret = %d)\n",
>> + event_notifier_get_fd(&intp->interrupt), ret);
>> + }
>> + } /* else this is a pending IRQ that moves to ACTIVE state */
>> +
>> + intp->state = VFIO_IRQ_ACTIVE;
>> +
>> + /* sets slow path */
>> + vfio_mmap_set_enabled(vdev, false);
>> +
>> + /* trigger the virtual IRQ */
>> + qemu_set_irq(intp->qemuirq, 1);
>> +
>> + /* schedule the mmap timer which will restore mmap path after EOI*/
>> + if (vdev->mmap_timeout) {
>> + timer_mod(vdev->mmap_timer,
>> + qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
>> + vdev->mmap_timeout);
>> + }
>> + qemu_mutex_unlock(&vdev->intp_mutex);
>> +}
>> +
>> +/**
>> + * vfio_start_eventfd_injection - starts the virtual IRQ injection using
>> + * user-side handled eventfds
>> + * @intp: the IRQ struct pointer
>> + */
>> +
>> +static int vfio_start_eventfd_injection(VFIOINTp *intp)
>> +{
>> + int ret;
>> + VFIODevice *vbasedev = &intp->vdev->vbasedev;
>> +
>> + vfio_mask_irqindex(vbasedev, intp->pin);
>> +
>> + ret = vfio_set_trigger_eventfd(intp, vfio_intp_interrupt);
>> + if (ret) {
>> + error_report("vfio: Error: Failed to pass IRQ fd to the driver: %m");
>> + vfio_unmask_irqindex(vbasedev, intp->pin);
>> + return ret;
>> + }
>> + vfio_unmask_irqindex(vbasedev, intp->pin);
>> + return 0;
>> +}
>> +
>> +/*
>> + * Functions used whatever the injection method
>> + */
>> +
>> +/**
>> + * vfio_set_trigger_eventfd - set VFIO eventfd handling
>> + * ie. program the VFIO driver to associates a given IRQ index
>> + * with a fd handler
>> + *
>> + * @intp: IRQ struct pointer
>> + * @handler: handler to be called on eventfd trigger
>> + */
>> +static int vfio_set_trigger_eventfd(VFIOINTp *intp,
>> + eventfd_user_side_handler_t handler)
>> +{
>> + VFIODevice *vbasedev = &intp->vdev->vbasedev;
>> + struct vfio_irq_set *irq_set;
>> + int argsz, ret;
>> + int32_t *pfd;
>> +
>> + argsz = sizeof(*irq_set) + sizeof(*pfd);
>> + irq_set = g_malloc0(argsz);
>> + irq_set->argsz = argsz;
>> + irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER;
>> + irq_set->index = intp->pin;
>> + irq_set->start = 0;
>> + irq_set->count = 1;
>> + pfd = (int32_t *)&irq_set->data;
>> + *pfd = event_notifier_get_fd(&intp->interrupt);
>> + qemu_set_fd_handler(*pfd, (IOHandler *)handler, NULL, intp);
>> + ret = ioctl(vbasedev->fd, VFIO_DEVICE_SET_IRQS, irq_set);
>> + g_free(irq_set);
>> + if (ret < 0) {
>> + error_report("vfio: Failed to set trigger eventfd: %m");
>> + qemu_set_fd_handler(*pfd, NULL, NULL, NULL);
>> + }
>> + return ret;
>> +}
>> +
>> +/* not implemented yet */
>> +static bool vfio_platform_compute_needs_reset(VFIODevice *vdev)
>> +{
>> +return false;
>> +}
>> +
>> +/* not implemented yet */
>> +static int vfio_platform_hot_reset_multi(VFIODevice *vdev)
>> +{
>> +return 0;
>> +}
>> +
>> +/**
>> + * vfio_init_intp - allocate, initialize the IRQ struct pointer
>> + * and add it into the list of IRQ
>> + * @vbasedev: the VFIO device
>> + * @index: VFIO device IRQ index
>> + */
>> +static VFIOINTp *vfio_init_intp(VFIODevice *vbasedev, unsigned int index)
>> +{
>> + int ret;
>> + VFIOPlatformDevice *vdev =
>> + container_of(vbasedev, VFIOPlatformDevice, vbasedev);
>> + SysBusDevice *sbdev = SYS_BUS_DEVICE(vdev);
>> + VFIOINTp *intp;
>> +
>> + /* allocate and populate a new VFIOINTp structure put in a queue list */
>> + intp = g_malloc0(sizeof(*intp));
>> + intp->vdev = vdev;
>> + intp->pin = index;
>> + intp->state = VFIO_IRQ_INACTIVE;
>> + sysbus_init_irq(sbdev, &intp->qemuirq);
>> +
>> + /* Get an eventfd for trigger */
>> + ret = event_notifier_init(&intp->interrupt, 0);
>> + if (ret) {
>> + g_free(intp);
>> + error_report("vfio: Error: trigger event_notifier_init failed ");
>> + return NULL;
>> + }
>> +
>> + /* store the new intp in qlist */
>> + QLIST_INSERT_HEAD(&vdev->intp_list, intp, next);
>> + return intp;
>> +}
>> +
>> +/**
>> + * vfio_populate_device - initialize MMIO region and IRQ
>> + * @vbasedev: the VFIO device
>> + *
>> + * query the VFIO device for exposed MMIO regions and IRQ and
>> + * populate the associated fields in the device struct
>> + */
>> +static int vfio_populate_device(VFIODevice *vbasedev)
>> +{
>> + struct vfio_irq_info irq = { .argsz = sizeof(irq) };
>> + struct vfio_region_info reg_info = { .argsz = sizeof(reg_info) };
>> + VFIOINTp *intp;
>> + int i, ret = 0;
>> + VFIOPlatformDevice *vdev =
>> + container_of(vbasedev, VFIOPlatformDevice, vbasedev);
>> +
>> + vdev->regions = g_malloc0(sizeof(VFIORegion *) * vbasedev->num_regions);
>> +
>> + for (i = 0; i < vbasedev->num_regions; i++) {
>> + vdev->regions[i] = g_malloc0(sizeof(VFIORegion));
>> + reg_info.index = i;
>> + ret = ioctl(vbasedev->fd, VFIO_DEVICE_GET_REGION_INFO, ®_info);
>> + if (ret) {
>> + error_report("vfio: Error getting region %d info: %m", i);
>> + goto error;
>> + }
>> + vdev->regions[i]->flags = reg_info.flags;
>> + vdev->regions[i]->size = reg_info.size;
>> + vdev->regions[i]->fd_offset = reg_info.offset;
>> + vdev->regions[i]->nr = i;
>> + vdev->regions[i]->vbasedev = vbasedev;
>> +
>> + trace_vfio_platform_populate_regions(vdev->regions[i]->nr,
>> + (unsigned long)vdev->regions[i]->flags,
>> + (unsigned long)vdev->regions[i]->size,
>> + vdev->regions[i]->vbasedev->fd,
>> + (unsigned long)vdev->regions[i]->fd_offset);
>> + }
>> +
>> + vdev->mmap_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL,
>> + vfio_intp_mmap_enable, vdev);
>> +
>> + QSIMPLEQ_INIT(&vdev->pending_intp_queue);
>> +
>> + for (i = 0; i < vbasedev->num_irqs; i++) {
>> + irq.index = i;
>> +
>> + ret = ioctl(vbasedev->fd, VFIO_DEVICE_GET_IRQ_INFO, &irq);
>> + if (ret) {
>> + error_printf("vfio: error getting device %s irq info",
>> + vbasedev->name);
>> + return ret;
>> + } else {
>> + trace_vfio_platform_populate_interrupts(irq.index,
>> + irq.count,
>> + irq.flags);
>> + intp = vfio_init_intp(vbasedev, irq.index);
>> + if (!intp) {
>> + error_report("vfio: Error installing IRQ %d up", i);
>> + return ret;
>> + }
>> + }
>> + }
>> + return 0;
>> +error:
>> + return ret;
>> +}
>> +
>> +/*
>> + * vfio_start_irq_injection - associates a virtual irq to a
>> + * VFIO IRQ index and start the injection of this IRQ
>> + * @s: SysBus Device
>> + * @index: VFIO IRQ index
>> + * @virq: the virtual IRQ number, aka gsi
>> + *
>> + * this function is called when the device tree is built
>> + */
>> +static void vfio_start_irq_injection(SysBusDevice *s, int index, int virq)
>> +{
>> + VFIOPlatformDevice *vdev = container_of(s, VFIOPlatformDevice, sbdev);
>> + VFIOINTp *intp;
>> +
>> + QLIST_FOREACH(intp, &vdev->intp_list, next) {
>> + if (intp->pin == index) {
>> + intp->virtualID = virq;
>> + vdev->start_irq_fn(intp);
>> + }
>> + }
>> +}
>> +
>> +/* specialized functions ofr VFIO Platform devices */
>> +static VFIODeviceOps vfio_platform_ops = {
>> + .vfio_compute_needs_reset = vfio_platform_compute_needs_reset,
>> + .vfio_hot_reset_multi = vfio_platform_hot_reset_multi,
>> + .vfio_eoi = vfio_platform_eoi,
>> + .vfio_populate_device = vfio_populate_device,
>> +};
>> +
>> +/**
>> + * vfio_base_device_init - implements some of the VFIO mechanics
>> + * @vbasedev: the VFIO device
>> + *
>> + * retrieves the group the device belongs to and get the device fd
>> + * returns the VFIO device fd
>> + * precondition: the device name must be initialized
>> + */
>> +static int vfio_base_device_init(VFIODevice *vbasedev)
>> +{
>> + VFIOGroup *group;
>> + VFIODevice *vbasedev_iter;
>> + char path[PATH_MAX], iommu_group_path[PATH_MAX], *group_name;
>> + ssize_t len;
>> + struct stat st;
>> + int groupid;
>> + int ret;
>> +
>> + /* name must be set prior to the call */
>> + if (!vbasedev->name) {
>> + return -EINVAL;
>> + }
>> +
>> + /* Check that the host device exists */
>> + snprintf(path, sizeof(path), "/sys/bus/platform/devices/%s/",
>> + vbasedev->name);
>> +
>> + if (stat(path, &st) < 0) {
>> + error_report("vfio: error: no such host device: %s", path);
>> + return -errno;
>> + }
>> +
>> + strncat(path, "iommu_group", sizeof(path) - strlen(path) - 1);
>> + len = readlink(path, iommu_group_path, sizeof(path));
>> + if (len <= 0 || len >= sizeof(path)) {
>> + error_report("vfio: error no iommu_group for device");
>> + return len < 0 ? -errno : ENAMETOOLONG;
>> + }
>> +
>> + iommu_group_path[len] = 0;
>> + group_name = basename(iommu_group_path);
>> +
>> + if (sscanf(group_name, "%d", &groupid) != 1) {
>> + error_report("vfio: error reading %s: %m", path);
>> + return -errno;
>> + }
>> +
>> + trace_vfio_platform_base_device_init(vbasedev->name, groupid);
>> +
>> + group = vfio_get_group(groupid, &address_space_memory);
>> + if (!group) {
>> + error_report("vfio: failed to get group %d", groupid);
>> + return -ENOENT;
>> + }
>> +
>> + snprintf(path, sizeof(path), "%s", vbasedev->name);
>> +
>> + QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
>> + if (strcmp(vbasedev_iter->name, vbasedev->name) == 0) {
>> + error_report("vfio: error: device %s is already attached", path);
>> + vfio_put_group(group);
>> + return -EBUSY;
>> + }
>> + }
>> + ret = vfio_get_device(group, path, vbasedev);
>> + if (ret) {
>> + error_report("vfio: failed to get device %s", path);
>> + vfio_put_group(group);
>> + }
>> + return ret;
>> +}
>> +
>> +/**
>> + * vfio_map_region - initialize the 2 mr (mmapped on ops) for a
>> + * given index
>> + * @vdev: the VFIO platform device
>> + * @nr: the index of the region
>> + *
>> + * init the top memory region and the mmapped memroy region beneath
>> + * VFIOPlatformDevice is used since VFIODevice is not a QOM Object
>> + * and could not be passed to memory region functions
>> +*/
>> +static void vfio_map_region(VFIOPlatformDevice *vdev, int nr)
>> +{
>> + VFIORegion *region = vdev->regions[nr];
>> + unsigned size = region->size;
>> + char name[64];
>> +
>> + if (!size) {
>> + return;
>> + }
>> +
>> + snprintf(name, sizeof(name), "VFIO %s region %d",
>> + vdev->vbasedev.name, nr);
>> +
>> + /* A "slow" read/write mapping underlies all regions */
>> + memory_region_init_io(®ion->mem, OBJECT(vdev), &vfio_region_ops,
>> + region, name, size);
>> +
>> + strncat(name, " mmap", sizeof(name) - strlen(name) - 1);
>> +
>> + if (vfio_mmap_region(OBJECT(vdev), region, ®ion->mem,
>> + ®ion->mmap_mem, ®ion->mmap, size, 0, name)) {
>> + error_report("%s unsupported. Performance may be slow", name);
>> + }
>> +}
>> +
>> +/**
>> + * vfio_platform_realize - the device realize function
>> + * @dev: device state pointer
>> + * @errp: error
>> + *
>> + * initialize the device, its memory regions and IRQ structures
>> + * IRQ are started separately
>> + */
>> +static void vfio_platform_realize(DeviceState *dev, Error **errp)
>> +{
>> + VFIOPlatformDevice *vdev = VFIO_PLATFORM_DEVICE(dev);
>> + SysBusDevice *sbdev = SYS_BUS_DEVICE(dev);
>> + VFIODevice *vbasedev = &vdev->vbasedev;
>> + int i, ret;
>> +
>> + vbasedev->type = VFIO_DEVICE_TYPE_PLATFORM;
>> + vbasedev->ops = &vfio_platform_ops;
>> + vdev->start_irq_fn = vfio_start_eventfd_injection;
>> +
>> + trace_vfio_platform_realize(vbasedev->name, vdev->compat);
>> +
>> + ret = vfio_base_device_init(vbasedev);
>> + if (ret) {
>> + error_setg(errp, "vfio: vfio_base_device_init failed for %s",
>> + vbasedev->name);
>> + return;
>> + }
>> +
>> + for (i = 0; i < vbasedev->num_regions; i++) {
>> + vfio_map_region(vdev, i);
>> + sysbus_init_mmio(sbdev, &vdev->regions[i]->mem);
>> + }
>> +}
>> +
>> +/*
>> + * Mechanics to program/start irq injection on machine init done notifier:
>> + * this is needed since at finalize time, the device IRQ are not yet
>> + * bound to the platform bus IRQ. It is assumed here dynamic instantiation
>> + * always is used. Binding to the platform bus IRQ happens on a machine
>> + * init done notifier registered by the machine file. After its execution
>> + * we execute a new notifier that actually starts the injection. When using
>> + * irqfd, programming the injection consists in associating eventfds to
>> + * GSI number,ie. virtual IRQ number
>> + */
>> +
>> +typedef struct VfioIrqStarterNotifierParams {
>> + unsigned int platform_bus_first_irq;
>> + Notifier notifier;
>> +} VfioIrqStarterNotifierParams;
>> +
>> +typedef struct VfioIrqStartParams {
>> + PlatformBusDevice *pbus;
>> + int platform_bus_first_irq;
>> +} VfioIrqStartParams;
>> +
>> +/* Start injection of IRQ for a specific VFIO device */
>> +static int vfio_irq_starter(SysBusDevice *sbdev, void *opaque)
>> +{
>> + int i;
>> + VfioIrqStartParams *p = opaque;
>> + VFIOPlatformDevice *vdev;
>> + VFIODevice *vbasedev;
>> + uint64_t irq_number;
>> + PlatformBusDevice *pbus = p->pbus;
>> + int platform_bus_first_irq = p->platform_bus_first_irq;
>> +
>> + if (object_dynamic_cast(OBJECT(sbdev), TYPE_VFIO_PLATFORM)) {
>> + vdev = VFIO_PLATFORM_DEVICE(sbdev);
>> + vbasedev = &vdev->vbasedev;
>> + for (i = 0; i < vbasedev->num_irqs; i++) {
>> + irq_number = platform_bus_get_irqn(pbus, sbdev, i)
>> + + platform_bus_first_irq;
>> + vfio_start_irq_injection(sbdev, i, irq_number);
>> + }
>> + }
>> + return 0;
>> +}
>> +
>> +/* loop on all VFIO platform devices and start their IRQ injection */
>> +static void vfio_irq_starter_notify(Notifier *notifier, void *data)
>> +{
>> + VfioIrqStarterNotifierParams *p =
>> + container_of(notifier, VfioIrqStarterNotifierParams, notifier);
>> + DeviceState *dev =
>> + qdev_find_recursive(sysbus_get_default(), TYPE_PLATFORM_BUS_DEVICE);
>> + PlatformBusDevice *pbus = PLATFORM_BUS_DEVICE(dev);
>> +
>> + if (pbus->done_gathering) {
>> + VfioIrqStartParams data = {
>> + .pbus = pbus,
>> + .platform_bus_first_irq = p->platform_bus_first_irq,
>> + };
>> +
>> + foreach_dynamic_sysbus_device(vfio_irq_starter, &data);
>> + }
>> +}
>> +
>> +/* registers the machine init done notifier that will start VFIO IRQ */
>> +void vfio_register_irq_starter(int platform_bus_first_irq)
>> +{
>> + VfioIrqStarterNotifierParams *p = g_new(VfioIrqStarterNotifierParams, 1);
>> +
>> + p->platform_bus_first_irq = platform_bus_first_irq;
>> + p->notifier.notify = vfio_irq_starter_notify;
>> + qemu_add_machine_init_done_notifier(&p->notifier);
>
> Could you add a notifier for each device instead? Then the notifier
> would be part of the vfio device struct and not some dangling random
> pointer :).
>
> Of course instead of foreach_dynamic_sysbus_device() you would directly
> know the device you're dealing with and only handle a single device per
> notifier.
Hi Alex,
Indeed I can do that and put the foreach in the machine file instead.
This means however more code in virt.c, in the create_platform_bus
function. If Peter agrees with that I will proceed.
I take the opportunity to ask a question I did not dare to ask yet about
qemu_irq ;-). Wouldn't it make sense to create an accessor to be able to
retrieve the IRQ number (n field). Indeed I currently do some gym to
pass the platform bus first irq and it would be definitively simpler to
directly retrieve n from qemu_irq. Besides I think we also have this
need when setting up irqfd for vhost net to associate the gsi with guest
notifier.
Thank you in advance
Best Regards
Eric
>
>
> Alex
>
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