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qemu/hw/vfio/platform.c

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/*
* vfio based device assignment support - platform devices
*
* Copyright Linaro Limited, 2014
*
* Authors:
* Kim Phillips <kim.phillips@linaro.org>
* Eric Auger <eric.auger@linaro.org>
*
* 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 "qemu/osdep.h"
#include "qapi/error.h"
#include <sys/ioctl.h>
#include <linux/vfio.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"
#include "sysemu/kvm.h"
/*
* Functions used whatever the injection method
*/
static inline bool vfio_irq_is_automasked(VFIOINTp *intp)
{
return intp->flags & VFIO_IRQ_INFO_AUTOMASKED;
}
/**
* vfio_init_intp - allocate, initialize the IRQ struct pointer
* and add it into the list of IRQs
* @vbasedev: the VFIO device handle
* @info: irq info struct retrieved from VFIO driver
*/
static VFIOINTp *vfio_init_intp(VFIODevice *vbasedev,
struct vfio_irq_info info)
{
int ret;
VFIOPlatformDevice *vdev =
container_of(vbasedev, VFIOPlatformDevice, vbasedev);
SysBusDevice *sbdev = SYS_BUS_DEVICE(vdev);
VFIOINTp *intp;
intp = g_malloc0(sizeof(*intp));
intp->vdev = vdev;
intp->pin = info.index;
intp->flags = info.flags;
intp->state = VFIO_IRQ_INACTIVE;
intp->kvm_accel = false;
sysbus_init_irq(sbdev, &intp->qemuirq);
/* Get an eventfd for trigger */
intp->interrupt = g_malloc0(sizeof(EventNotifier));
ret = event_notifier_init(intp->interrupt, 0);
if (ret) {
g_free(intp->interrupt);
g_free(intp);
error_report("vfio: Error: trigger event_notifier_init failed ");
return NULL;
}
if (vfio_irq_is_automasked(intp)) {
/* Get an eventfd for resample/unmask */
intp->unmask = g_malloc0(sizeof(EventNotifier));
ret = event_notifier_init(intp->unmask, 0);
if (ret) {
g_free(intp->interrupt);
g_free(intp->unmask);
g_free(intp);
error_report("vfio: Error: resamplefd event_notifier_init failed");
return NULL;
}
}
QLIST_INSERT_HEAD(&vdev->intp_list, intp, next);
return intp;
}
/**
* vfio_set_trigger_eventfd - set VFIO eventfd handling
*
* @intp: IRQ struct handle
* @handler: handler to be called on eventfd signaling
*
* Setup VFIO signaling and attach an optional user-side handler
* to the eventfd
*/
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;
}
/*
* Functions only used when eventfds are handled on user-side
* ie. without irqfd
*/
/**
* vfio_mmap_set_enabled - enable/disable the fast path mode
* @vdev: the VFIO platform device
* @enabled: the target mmap state
*
* enabled = true ~ fast path = MMIO region is mmaped (no KVM TRAP);
* enabled = false ~ slow path = MMIO region is trapped and region callbacks
* are called; slow path enables to trap the device IRQ status register reset
*/
static void vfio_mmap_set_enabled(VFIOPlatformDevice *vdev, bool enabled)
{
int i;
for (i = 0; i < vdev->vbasedev.num_regions; i++) {
vfio_region_mmaps_set_enabled(vdev->regions[i], 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 if not, restores the fast path.
* by construction a single eventfd is handled at a time.
* if the IRQ is still active, the timer is re-programmed.
*/
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_inject_pending_lockheld - Injects a pending IRQ
* @opaque: opaque pointer, in practice the VFIOINTp handle
*
* The function is called on a previous IRQ completion, from
* vfio_platform_eoi, while the intp_mutex is locked.
* Also in such situation, the slow path already is set and
* the mmap timer was already programmed.
*/
static void vfio_intp_inject_pending_lockheld(VFIOINTp *intp)
{
trace_vfio_platform_intp_inject_pending_lockheld(intp->pin,
event_notifier_get_fd(intp->interrupt));
intp->state = VFIO_IRQ_ACTIVE;
/* trigger the virtual IRQ */
qemu_set_irq(intp->qemuirq, 1);
}
/**
* vfio_intp_interrupt - The user-side eventfd handler
* @opaque: opaque pointer which in practice is the VFIOINTp handle
*
* the function is entered in event handler context:
* the vIRQ is injected into the guest if there is no other active
* or pending 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;
}
trace_vfio_platform_intp_interrupt(intp->pin,
event_notifier_get_fd(intp->interrupt));
ret = event_notifier_test_and_clear(intp->interrupt);
if (!ret) {
error_report("Error when clearing fd=%d (ret = %d)",
event_notifier_get_fd(intp->interrupt), ret);
}
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 fastpath when no IRQ
* is active anymore
*/
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_platform_eoi - IRQ completion routine
* @vbasedev: the VFIO device handle
*
* De-asserts the active virtual IRQ and unmasks the physical IRQ
* (effective for level sensitive IRQ auto-masked by the VFIO driver).
* Then it handles next pending IRQ if any.
* eoi function is called on the first access to any MMIO region
* after an IRQ was triggered, trapped since slow path was set.
* 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 */
qemu_set_irq(intp->qemuirq, 0);
if (vfio_irq_is_automasked(intp)) {
/* unmasks the physical level-sensitive IRQ */
vfio_unmask_single_irqindex(vbasedev, intp->pin);
}
/* a single IRQ can be active at a time */
break;
}
}
/* in case there are pending IRQs, handle the first one */
if (!QSIMPLEQ_EMPTY(&vdev->pending_intp_queue)) {
intp = QSIMPLEQ_FIRST(&vdev->pending_intp_queue);
vfio_intp_inject_pending_lockheld(intp);
QSIMPLEQ_REMOVE_HEAD(&vdev->pending_intp_queue, pqnext);
}
qemu_mutex_unlock(&vdev->intp_mutex);
}
/**
* vfio_start_eventfd_injection - starts the virtual IRQ injection using
* user-side handled eventfds
* @sbdev: the sysbus device handle
* @irq: the qemu irq handle
*/
static void vfio_start_eventfd_injection(SysBusDevice *sbdev, qemu_irq irq)
{
int ret;
VFIOPlatformDevice *vdev = VFIO_PLATFORM_DEVICE(sbdev);
VFIOINTp *intp;
QLIST_FOREACH(intp, &vdev->intp_list, next) {
if (intp->qemuirq == irq) {
break;
}
}
assert(intp);
ret = vfio_set_trigger_eventfd(intp, vfio_intp_interrupt);
if (ret) {
error_report("vfio: failed to start eventfd signaling for IRQ %d: %m",
intp->pin);
abort();
}
}
/*
* Functions used for irqfd
*/
/**
* vfio_set_resample_eventfd - sets the resamplefd for an IRQ
* @intp: the IRQ struct handle
* programs the VFIO driver to unmask this IRQ when the
* intp->unmask eventfd is triggered
*/
static int vfio_set_resample_eventfd(VFIOINTp *intp)
{
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_UNMASK;
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->unmask);
qemu_set_fd_handler(*pfd, NULL, NULL, NULL);
ret = ioctl(vbasedev->fd, VFIO_DEVICE_SET_IRQS, irq_set);
g_free(irq_set);
if (ret < 0) {
error_report("vfio: Failed to set resample eventfd: %m");
}
return ret;
}
/**
* vfio_start_irqfd_injection - starts the virtual IRQ injection using
* irqfd
*
* @sbdev: the sysbus device handle
* @irq: the qemu irq handle
*
* In case the irqfd setup fails, we fallback to userspace handled eventfd
*/
static void vfio_start_irqfd_injection(SysBusDevice *sbdev, qemu_irq irq)
{
VFIOPlatformDevice *vdev = VFIO_PLATFORM_DEVICE(sbdev);
VFIOINTp *intp;
if (!kvm_irqfds_enabled() || !kvm_resamplefds_enabled() ||
!vdev->irqfd_allowed) {
goto fail_irqfd;
}
QLIST_FOREACH(intp, &vdev->intp_list, next) {
if (intp->qemuirq == irq) {
break;
}
}
assert(intp);
if (kvm_irqchip_add_irqfd_notifier(kvm_state, intp->interrupt,
intp->unmask, irq) < 0) {
goto fail_irqfd;
}
if (vfio_set_trigger_eventfd(intp, NULL) < 0) {
goto fail_vfio;
}
if (vfio_irq_is_automasked(intp)) {
if (vfio_set_resample_eventfd(intp) < 0) {
goto fail_vfio;
}
trace_vfio_platform_start_level_irqfd_injection(intp->pin,
event_notifier_get_fd(intp->interrupt),
event_notifier_get_fd(intp->unmask));
} else {
trace_vfio_platform_start_edge_irqfd_injection(intp->pin,
event_notifier_get_fd(intp->interrupt));
}
intp->kvm_accel = true;
return;
fail_vfio:
kvm_irqchip_remove_irqfd_notifier(kvm_state, intp->interrupt, irq);
error_report("vfio: failed to start eventfd signaling for IRQ %d: %m",
intp->pin);
abort();
fail_irqfd:
vfio_start_eventfd_injection(sbdev, irq);
return;
}
/* VFIO skeleton */
static void vfio_platform_compute_needs_reset(VFIODevice *vbasedev)
{
vbasedev->needs_reset = true;
}
/* not implemented yet */
static int vfio_platform_hot_reset_multi(VFIODevice *vbasedev)
{
return -1;
}
/**
* vfio_populate_device - Allocate and populate MMIO region
* and IRQ structs according to driver returned information
* @vbasedev: the VFIO device handle
*
*/
static int vfio_populate_device(VFIODevice *vbasedev)
{
VFIOINTp *intp, *tmp;
int i, ret = -1;
VFIOPlatformDevice *vdev =
container_of(vbasedev, VFIOPlatformDevice, vbasedev);
if (!(vbasedev->flags & VFIO_DEVICE_FLAGS_PLATFORM)) {
error_report("vfio: Um, this isn't a platform device");
return ret;
}
vdev->regions = g_new0(VFIORegion *, vbasedev->num_regions);
for (i = 0; i < vbasedev->num_regions; i++) {
char *name = g_strdup_printf("VFIO %s region %d\n", vbasedev->name, i);
vdev->regions[i] = g_new0(VFIORegion, 1);
ret = vfio_region_setup(OBJECT(vdev), vbasedev,
vdev->regions[i], i, name);
g_free(name);
if (ret) {
error_report("vfio: Error getting region %d info: %m", i);
goto reg_error;
}
}
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++) {
struct vfio_irq_info irq = { .argsz = sizeof(irq) };
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);
goto irq_err;
} else {
trace_vfio_platform_populate_interrupts(irq.index,
irq.count,
irq.flags);
intp = vfio_init_intp(vbasedev, irq);
if (!intp) {
error_report("vfio: Error installing IRQ %d up", i);
goto irq_err;
}
}
}
return 0;
irq_err:
timer_del(vdev->mmap_timer);
QLIST_FOREACH_SAFE(intp, &vdev->intp_list, next, tmp) {
QLIST_REMOVE(intp, next);
g_free(intp);
}
reg_error:
for (i = 0; i < vbasedev->num_regions; i++) {
if (vdev->regions[i]) {
vfio_region_finalize(vdev->regions[i]);
}
g_free(vdev->regions[i]);
}
g_free(vdev->regions);
return ret;
}
/* specialized functions for 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_base_device_init - perform preliminary VFIO setup
* @vbasedev: the VFIO device handle
*
* Implement the VFIO command sequence that allows to discover
* assigned device resources: group extraction, device
* fd retrieval, resource query.
* Precondition: the device name must be initialized
*/
static int vfio_base_device_init(VFIODevice *vbasedev)
{
VFIOGroup *group;
VFIODevice *vbasedev_iter;
char *tmp, group_path[PATH_MAX], *group_name;
ssize_t len;
struct stat st;
int groupid;
int ret;
/* @sysfsdev takes precedence over @host */
if (vbasedev->sysfsdev) {
g_free(vbasedev->name);
vbasedev->name = g_strdup(basename(vbasedev->sysfsdev));
} else {
if (!vbasedev->name || strchr(vbasedev->name, '/')) {
return -EINVAL;
}
vbasedev->sysfsdev = g_strdup_printf("/sys/bus/platform/devices/%s",
vbasedev->name);
}
if (stat(vbasedev->sysfsdev, &st) < 0) {
error_report("vfio: error: no such host device: %s",
vbasedev->sysfsdev);
return -errno;
}
tmp = g_strdup_printf("%s/iommu_group", vbasedev->sysfsdev);
len = readlink(tmp, group_path, sizeof(group_path));
g_free(tmp);
if (len < 0 || len >= sizeof(group_path)) {
error_report("vfio: error no iommu_group for device");
return len < 0 ? -errno : -ENAMETOOLONG;
}
group_path[len] = 0;
group_name = basename(group_path);
if (sscanf(group_name, "%d", &groupid) != 1) {
error_report("vfio: error reading %s: %m", group_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;
}
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",
vbasedev->name);
vfio_put_group(group);
return -EBUSY;
}
}
ret = vfio_get_device(group, vbasedev->name, vbasedev);
if (ret) {
error_report("vfio: failed to get device %s", vbasedev->name);
vfio_put_group(group);
return ret;
}
ret = vfio_populate_device(vbasedev);
if (ret) {
error_report("vfio: failed to populate device %s", vbasedev->name);
vfio_put_group(group);
}
return ret;
}
/**
* 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;
trace_vfio_platform_realize(vbasedev->sysfsdev ?
vbasedev->sysfsdev : 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++) {
if (vfio_region_mmap(vdev->regions[i])) {
error_report("%s mmap unsupported. Performance may be slow",
memory_region_name(vdev->regions[i]->mem));
}
sysbus_init_mmio(sbdev, vdev->regions[i]->mem);
}
}
static const VMStateDescription vfio_platform_vmstate = {
.name = TYPE_VFIO_PLATFORM,
.unmigratable = 1,
};
static Property vfio_platform_dev_properties[] = {
DEFINE_PROP_STRING("host", VFIOPlatformDevice, vbasedev.name),
DEFINE_PROP_STRING("sysfsdev", VFIOPlatformDevice, vbasedev.sysfsdev),
DEFINE_PROP_BOOL("x-no-mmap", VFIOPlatformDevice, vbasedev.no_mmap, false),
DEFINE_PROP_UINT32("mmap-timeout-ms", VFIOPlatformDevice,
mmap_timeout, 1100),
DEFINE_PROP_BOOL("x-irqfd", VFIOPlatformDevice, irqfd_allowed, true),
DEFINE_PROP_END_OF_LIST(),
};
static void vfio_platform_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
SysBusDeviceClass *sbc = SYS_BUS_DEVICE_CLASS(klass);
dc->realize = vfio_platform_realize;
dc->props = vfio_platform_dev_properties;
dc->vmsd = &vfio_platform_vmstate;
dc->desc = "VFIO-based platform device assignment";
sbc->connect_irq_notifier = vfio_start_irqfd_injection;
set_bit(DEVICE_CATEGORY_MISC, dc->categories);
}
static const TypeInfo vfio_platform_dev_info = {
.name = TYPE_VFIO_PLATFORM,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(VFIOPlatformDevice),
.class_init = vfio_platform_class_init,
.class_size = sizeof(VFIOPlatformDeviceClass),
.abstract = true,
};
static void register_vfio_platform_dev_type(void)
{
type_register_static(&vfio_platform_dev_info);
}
type_init(register_vfio_platform_dev_type)
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