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Date: Thu, 15 Jun 2023 16:54:01 -0600
From: Alex Williamson <alex.williamson@...hat.com>
To: Grzegorz Jaszczyk <jaz@...ihalf.com>
Cc: linux-kernel@...r.kernel.org, dmy@...ihalf.com, tn@...ihalf.com,
dbehr@...gle.com, dbehr@...omium.org, upstream@...ihalf.com,
dtor@...gle.com, jgg@...pe.ca, kevin.tian@...el.com,
cohuck@...hat.com, abhsahu@...dia.com, yishaih@...dia.com,
yi.l.liu@...el.com, kvm@...r.kernel.org, libvir-list@...hat.com,
pmorel@...ux.ibm.com, borntraeger@...ux.ibm.com,
mjrosato@...ux.ibm.com
Subject: Re: [PATCH v5] vfio/pci: Propagate ACPI notifications to user-space
via eventfd
On Fri, 9 Jun 2023 13:39:50 +0000
Grzegorz Jaszczyk <jaz@...ihalf.com> wrote:
> To allow pass-through devices receiving ACPI notifications, permit to
> register ACPI notify handler (via VFIO_DEVICE_SET_IRQS) for a given
> device. The handler role is to receive and propagate such ACPI
> notifications to the user-space through the user provided eventfd. This
> allows VMM to receive and propagate them further to the VM, where the
> actual driver for pass-through device resides and can react to device
> specific notifications accordingly.
>
> The eventfd usage ensures VMM and device isolation: it allows to use a
> dedicated channel associated with the device for such events, such that
> the VMM has direct access.
>
> Since the eventfd counter is used as ACPI notification value
> placeholder, the eventfd signaling needs to be serialized in order to
> not end up with notification values being coalesced. Therefore ACPI
> notification values are buffered and signalized one by one, when the
> previous notification value has been consumed.
>
> Signed-off-by: Grzegorz Jaszczyk <jaz@...ihalf.com>
> ---
> Changelog v4..v5
> Address Alex Williamson's feedback:
> - s/vfio_acpi_notify.{c,o}/acpi_notify.{c,o}
> - Do not put acpi_notify to its own module but fold it into main
> vfio.ko. Additionally select it from VFIO_PCI_CORE instead of VFIO_PCI.
> - Cleanup acpi notify under igate mutex (in vfio_pci_core_close_device).
> - Add extra check for ACPI companion in vfio_pci_get_irq_count and
> extend vfio_pci_ioctl_get_irq_info.
> - Drop acpi.h include - linux/vfio_acpi_notify.h includes it already.
> - Send device check notification value for DATA_NONE and non-zero count
> and for DATA_BOOL and non-zero count (as for loopback testing).
> - Drop some redundant !acpi_notify->acpi_notify_trigger checks.
> - Move some common code to new helper functions:
> 1) acpi_notification_dequeue
> 2) vfio_acpi_notify_cleanup and rename previous
> vfio_acpi_notify_cleanup into vfio_remove_acpi_notify which uses it
> - Add rate limited logging for dropped notifications.
> - Move vdev->acpi_notification pointer cleanup to the
> vfio_acpi_notify_cleanup function this also fixes two bigger issues
> caught by Alex.
> - Allow the eventfd to be swapped.
> - s/GFP_KERNEL/GFP_KERNEL_ACCOUNT.
> - s/VFIO_PCI_ACPI_NTFY_IRQ_INDEX/VFIO_PCI_ACPI_IRQ_INDEX.
> - Add header protection for multiple includes.
> - v4: https://patchwork.kernel.org/project/kvm/patch/20230522165811.123417-1-jaz@semihalf.com/
>
> Changelog v3..v4
> Address Alex Williamson feedback:
> - Instead of introducing new ioctl used for eventfd registration, take
> advantage of VFIO_DEVICE_SET_IRQS which already supports virtual IRQs
> for things like error notification and device release requests.
> - Introduced mechanism preventing creation of large queues.
> Other:
> - Move the implementation into the newly introduced VFIO_ACPI_NOTIFY
> helper module. It is actually not bound to VFIO_PCI but VFIO_PCI
> enables it whenever ACPI support is enabled. This change is introduced
> since ACPI notifications are not limited to PCI devices, making it PCI
> independent will allow to re-use it also for other VFIO_* like
> supports: e.g. VFIO_PLATFORM in the future if needed. Moving it out of
> drivers/vfio/pci/ was also suggested offline.
> - s/notify_val_next/node
> - v3: https://patchwork.kernel.org/project/kvm/patch/20230502132700.654528-1-jaszczyk@google.com/
>
> Changelog v2..v3:
> - Fix compilation warnings when building with "W=1"
>
> Changelog v1..v2:
> - The v2 implementation is actually completely different then v1:
> instead of using acpi netlink events for propagating ACPI
> notifications to the user space take advantage of eventfd, which can
> provide better VMM and device isolation: it allows to use a dedicated
> channel associated with the device for such events, such that the VMM
> has direct access.
> - Using eventfd counter as notification value placeholder was suggested
> in v1 and requires additional serialization logic introduced in v2.
> - Since the vfio-pci supports non-ACPI platforms address !CONFIG_ACPI
> case.
> - v1 discussion: https://patchwork.kernel.org/project/kvm/patch/20230307220553.631069-1-jaz@semihalf.com/
> ---
> drivers/vfio/Kconfig | 5 +
> drivers/vfio/Makefile | 1 +
> drivers/vfio/acpi_notify.c | 249 ++++++++++++++++++++++++++++++
> drivers/vfio/pci/Kconfig | 1 +
> drivers/vfio/pci/vfio_pci_core.c | 13 ++
> drivers/vfio/pci/vfio_pci_intrs.c | 85 ++++++++++
> include/linux/vfio_acpi_notify.h | 45 ++++++
> include/linux/vfio_pci_core.h | 1 +
> include/uapi/linux/vfio.h | 1 +
> 9 files changed, 401 insertions(+)
> create mode 100644 drivers/vfio/acpi_notify.c
> create mode 100644 include/linux/vfio_acpi_notify.h
>
> diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig
> index 89e06c981e43..cd9df43a4eb4 100644
> --- a/drivers/vfio/Kconfig
> +++ b/drivers/vfio/Kconfig
> @@ -12,6 +12,11 @@ menuconfig VFIO
> If you don't know what to do here, say N.
>
> if VFIO
> +config VFIO_ACPI_NOTIFY
> + bool
> + depends on ACPI
> + default n
> +
> config VFIO_CONTAINER
> bool "Support for the VFIO container /dev/vfio/vfio"
> select VFIO_IOMMU_TYPE1 if MMU && (X86 || S390 || ARM || ARM64)
> diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
> index 70e7dcb302ef..003c2b041785 100644
> --- a/drivers/vfio/Makefile
> +++ b/drivers/vfio/Makefile
> @@ -7,6 +7,7 @@ vfio-y += vfio_main.o \
> vfio-$(CONFIG_IOMMUFD) += iommufd.o
> vfio-$(CONFIG_VFIO_CONTAINER) += container.o
> vfio-$(CONFIG_VFIO_VIRQFD) += virqfd.o
> +vfio-$(CONFIG_VFIO_ACPI_NOTIFY) += acpi_notify.o
>
> obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o
> obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o
> diff --git a/drivers/vfio/acpi_notify.c b/drivers/vfio/acpi_notify.c
> new file mode 100644
> index 000000000000..8d3f063502fe
> --- /dev/null
> +++ b/drivers/vfio/acpi_notify.c
> @@ -0,0 +1,249 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * VFIO ACPI notification propagation
> + *
> + * Author: Grzegorz Jaszczyk <jaz@...ihalf.com>
> + */
> +#include <linux/vfio_acpi_notify.h>
> +
> +#define NOTIFICATION_QUEUE_SIZE 20
> +
> +struct notification_queue {
> + int notification_val;
> + struct list_head node;
> +};
> +
> +static int vfio_eventfd_wakeup(wait_queue_entry_t *wait, unsigned int mode,
> + int sync, void *key)
> +{
> + struct vfio_acpi_notification *acpi_notify =
> + container_of(wait, struct vfio_acpi_notification, wait);
> + __poll_t flags = key_to_poll(key);
Lockdep annotation would be useful throughout:
lockdep_assert_held(&acpi_notify->notification_lock);
> +
> + /*
> + * eventfd_read signalize EPOLLOUT at the end of its function - this
> + * means previous eventfd with its notification value was consumed so
> + * the next notification can be signalized now if pending - schedule
> + * proper work.
> + */
> + if (flags & EPOLLOUT) {
> + mutex_unlock(&acpi_notify->notification_lock);
> + schedule_work(&acpi_notify->acpi_notification_work);
> + }
Shouldn't we also handle EPOLLHUP here? For example, isn't there a
deadlock if the user configures a notification eventfd, a notification
fires, the user closes the eventfd without reading it, and then tries
to swap in a different eventfd ctx?
Having this mutex held indefinitely waiting on the user to poll the
eventfd looks problematic.
> +
> + return 0;
> +}
> +
> +static void vfio_ptable_queue_proc(struct file *file,
> + wait_queue_head_t *wqh, poll_table *pt)
> +{
> + struct vfio_acpi_notification *acpi_notify =
> + container_of(pt, struct vfio_acpi_notification, pt);
> +
> + add_wait_queue(wqh, &acpi_notify->wait);
> +}
> +
> +static struct notification_queue *
> +acpi_notification_dequeue(struct vfio_acpi_notification *acpi_notify)
> +{
> + struct notification_queue *oldest_entry;
> +
lockdep_assert_held(&&acpi_notify->notification_list_lock);
lockdep_assert_held(&&acpi_notify->notification_lock);
> + oldest_entry = list_first_entry(&acpi_notify->notification_list,
> + struct notification_queue,
> + node);
> + list_del(&oldest_entry->node);
> + acpi_notify->notification_queue_count--;
> +
> + return oldest_entry;
> +}
> +
> +static void acpi_notification_work_fn(struct work_struct *work)
> +{
> + struct vfio_acpi_notification *acpi_notify;
> + struct notification_queue *entry;
> +
> + acpi_notify = container_of(work, struct vfio_acpi_notification,
> + acpi_notification_work);
> +
> + mutex_lock(&acpi_notify->notification_list_lock);
> + if (list_empty(&acpi_notify->notification_list))
> + goto out;
> +
> + /*
> + * If the previous eventfd was not yet consumed by user-space lets hold
> + * on and exit. The notification function will be rescheduled when
> + * signaling eventfd will be possible (when the EPOLLOUT will be
> + * signalized and unlocks notify_events).
> + */
> + if (!mutex_trylock(&acpi_notify->notification_lock))
> + goto out;
> +
> + entry = acpi_notification_dequeue(acpi_notify);
> +
> + mutex_unlock(&acpi_notify->notification_list_lock);
> +
> + eventfd_signal(acpi_notify->acpi_notify_trigger, entry->notification_val);
> +
> + kfree(entry);
> +
> + return;
> +out:
> + mutex_unlock(&acpi_notify->notification_list_lock);
> +}
> +
> +static void
> +vfio_acpi_notify_cleanup(struct vfio_acpi_notification **acpi_notify_ptr,
> + struct acpi_device *adev)
> +{
> + struct vfio_acpi_notification *acpi_notify = *acpi_notify_ptr;
> + struct notification_queue *entry, *entry_tmp;
> + u64 cnt;
> +
> + eventfd_ctx_remove_wait_queue(acpi_notify->acpi_notify_trigger,
> + &acpi_notify->wait, &cnt);
> +
> + flush_work(&acpi_notify->acpi_notification_work);
At this point we have no idea the state of notification_lock, we'd need
something like:
if (mutex_trylock(&acpi_notify->notification_lock))
mutex_unlock(&acpi_notify->notification_lock);
But that is super sketchy.
> +
> + mutex_lock(&acpi_notify->notification_list_lock);
> + list_for_each_entry_safe(entry, entry_tmp,
> + &acpi_notify->notification_list,
> + node) {
> + list_del(&entry->node);
> + kfree(entry);
> + }
> + mutex_unlock(&acpi_notify->notification_list_lock);
> +
> + eventfd_ctx_put(acpi_notify->acpi_notify_trigger);
> +
> + kfree(acpi_notify);
> +
> + *acpi_notify_ptr = NULL;
> +}
> +
> +void vfio_acpi_notify(acpi_handle handle, u32 event, void *data)
> +{
> + struct vfio_acpi_notification *acpi_notify = (struct vfio_acpi_notification *)data;
> + struct notification_queue *entry;
> +
> + entry = kmalloc(sizeof(*entry), GFP_KERNEL);
> + if (!entry)
> + return;
> +
> + entry->notification_val = event;
> + INIT_LIST_HEAD(&entry->node);
> +
> + mutex_lock(&acpi_notify->notification_list_lock);
> + if (acpi_notify->notification_queue_count > NOTIFICATION_QUEUE_SIZE) {
> + struct notification_queue *oldest_entry =
> + acpi_notification_dequeue(acpi_notify);
> +
> + if (printk_ratelimit())
> + acpi_handle_warn(handle,
> + "dropping notification value %d\n",
> + oldest_entry->notification_val);
> +
> + kfree(oldest_entry);
> + }
> + list_add_tail(&entry->node, &acpi_notify->notification_list);
> + acpi_notify->notification_queue_count++;
> + mutex_unlock(&acpi_notify->notification_list_lock);
> +
> + schedule_work(&acpi_notify->acpi_notification_work);
> +}
> +EXPORT_SYMBOL_GPL(vfio_acpi_notify);
> +
> +void vfio_remove_acpi_notify(struct vfio_acpi_notification **acpi_notify_ptr,
> + struct acpi_device *adev)
> +{
> + struct vfio_acpi_notification *acpi_notify = *acpi_notify_ptr;
> +
> + if (!acpi_notify)
> + return;
> +
> + acpi_remove_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
> + vfio_acpi_notify);
> +
> + vfio_acpi_notify_cleanup(acpi_notify_ptr, adev);
> +}
> +EXPORT_SYMBOL_GPL(vfio_remove_acpi_notify);
> +
> +int vfio_register_acpi_notify_handler(struct vfio_acpi_notification **acpi_notify_ptr,
> + struct acpi_device *adev, int32_t fd)
> +{
> + struct vfio_acpi_notification *acpi_notify = *acpi_notify_ptr;
> + struct file *acpi_notify_trigger_file;
> + struct eventfd_ctx *efdctx;
> + acpi_status status;
> +
> + if (fd < -1)
> + return -EINVAL;
> + else if (fd == -1) {
> + vfio_remove_acpi_notify(acpi_notify_ptr, adev);
> + return 0;
> + }
> +
> + efdctx = eventfd_ctx_fdget(fd);
> + if (IS_ERR(efdctx))
> + return PTR_ERR(efdctx);
> +
> + /* Allow eventfd to be swapped */
> + if (acpi_notify) {
> + u64 cnt;
> +
> + acpi_notify_trigger_file = eventfd_fget(fd);
Where's the fput() for any of these eventfd_fget() calls?
> +
> + mutex_lock(&acpi_notify->notification_lock);
A pending signal deadlocks here.
> + eventfd_ctx_remove_wait_queue(acpi_notify->acpi_notify_trigger,
> + &acpi_notify->wait, &cnt);
> + eventfd_ctx_put(acpi_notify->acpi_notify_trigger);
> + acpi_notify->acpi_notify_trigger = efdctx;
> + vfs_poll(acpi_notify_trigger_file, &acpi_notify->pt);
> + mutex_unlock(&acpi_notify->notification_lock);
> +
> + /*
> + * The ACPI notifications could arrive and be queued during
> + * eventfd swap, retrigger the worker after notification
> + * replication unlocking.
> + */
> + schedule_work(&acpi_notify->acpi_notification_work);
> +
> + return 0;
> + }
> +
> + acpi_notify = kzalloc(sizeof(*acpi_notify), GFP_KERNEL_ACCOUNT);
> + if (!acpi_notify)
> + return -ENOMEM;
> +
> + *acpi_notify_ptr = acpi_notify;
> +
> + INIT_WORK(&acpi_notify->acpi_notification_work, acpi_notification_work_fn);
> + INIT_LIST_HEAD(&acpi_notify->notification_list);
> +
> + acpi_notify->acpi_notify_trigger = efdctx;
> +
> + mutex_init(&acpi_notify->notification_lock);
> +
> + /*
> + * Install custom wake-up handler to be notified whenever underlying
> + * eventfd is consumed by the user-space.
> + */
> + init_waitqueue_func_entry(&acpi_notify->wait, vfio_eventfd_wakeup);
> + init_poll_funcptr(&acpi_notify->pt, vfio_ptable_queue_proc);
> +
> + acpi_notify_trigger_file = eventfd_fget(fd);
> + vfs_poll(acpi_notify_trigger_file, &acpi_notify->pt);
> +
> + status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
> + vfio_acpi_notify, (void *)acpi_notify);
> + if (ACPI_FAILURE(status)) {
> + dev_err(&adev->dev, "Failed to install notify handler: %s",
> + acpi_format_exception(status));
> +
> + vfio_acpi_notify_cleanup(acpi_notify_ptr, adev);
> +
> + return -ENODEV;
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(vfio_register_acpi_notify_handler);
> diff --git a/drivers/vfio/pci/Kconfig b/drivers/vfio/pci/Kconfig
> index f9d0c908e738..f03ca773dfd9 100644
> --- a/drivers/vfio/pci/Kconfig
> +++ b/drivers/vfio/pci/Kconfig
> @@ -4,6 +4,7 @@ config VFIO_PCI_CORE
> tristate
> select VFIO_VIRQFD
> select IRQ_BYPASS_MANAGER
> + select VFIO_ACPI_NOTIFY if ACPI
>
> config VFIO_PCI_MMAP
> def_bool y if !S390
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index a5ab416cf476..1cc4a9c05403 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -27,6 +27,7 @@
> #include <linux/vgaarb.h>
> #include <linux/nospec.h>
> #include <linux/sched/mm.h>
> +#include <linux/vfio_acpi_notify.h>
> #if IS_ENABLED(CONFIG_EEH)
> #include <asm/eeh.h>
> #endif
> @@ -683,6 +684,7 @@ void vfio_pci_core_close_device(struct vfio_device *core_vdev)
> {
> struct vfio_pci_core_device *vdev =
> container_of(core_vdev, struct vfio_pci_core_device, vdev);
> + struct acpi_device *adev = ACPI_COMPANION(&vdev->pdev->dev);
>
> if (vdev->sriov_pf_core_dev) {
> mutex_lock(&vdev->sriov_pf_core_dev->vf_token->lock);
> @@ -704,6 +706,8 @@ void vfio_pci_core_close_device(struct vfio_device *core_vdev)
> eventfd_ctx_put(vdev->req_trigger);
> vdev->req_trigger = NULL;
> }
> + if (adev)
> + vfio_remove_acpi_notify(&vdev->acpi_notification, adev);
> mutex_unlock(&vdev->igate);
> }
> EXPORT_SYMBOL_GPL(vfio_pci_core_close_device);
> @@ -725,6 +729,8 @@ EXPORT_SYMBOL_GPL(vfio_pci_core_finish_enable);
>
> static int vfio_pci_get_irq_count(struct vfio_pci_core_device *vdev, int irq_type)
> {
> + struct acpi_device *adev = ACPI_COMPANION(&vdev->pdev->dev);
> +
> if (irq_type == VFIO_PCI_INTX_IRQ_INDEX) {
> u8 pin;
>
> @@ -761,6 +767,8 @@ static int vfio_pci_get_irq_count(struct vfio_pci_core_device *vdev, int irq_typ
> return 1;
> } else if (irq_type == VFIO_PCI_REQ_IRQ_INDEX) {
> return 1;
> + } else if (adev && irq_type == VFIO_PCI_ACPI_IRQ_INDEX) {
> + return 1;
> }
>
> return 0;
> @@ -1084,6 +1092,7 @@ static int vfio_pci_ioctl_get_irq_info(struct vfio_pci_core_device *vdev,
> struct vfio_irq_info __user *arg)
> {
> unsigned long minsz = offsetofend(struct vfio_irq_info, count);
> + struct acpi_device *adev = ACPI_COMPANION(&vdev->pdev->dev);
> struct vfio_irq_info info;
>
> if (copy_from_user(&info, arg, minsz))
> @@ -1096,6 +1105,10 @@ static int vfio_pci_ioctl_get_irq_info(struct vfio_pci_core_device *vdev,
> case VFIO_PCI_INTX_IRQ_INDEX ... VFIO_PCI_MSIX_IRQ_INDEX:
> case VFIO_PCI_REQ_IRQ_INDEX:
> break;
> + case VFIO_PCI_ACPI_IRQ_INDEX:
> + if (adev)
> + break;
> + return -EINVAL;
> case VFIO_PCI_ERR_IRQ_INDEX:
> if (pci_is_pcie(vdev->pdev))
> break;
> diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
> index bffb0741518b..410f517f8b2c 100644
> --- a/drivers/vfio/pci/vfio_pci_intrs.c
> +++ b/drivers/vfio/pci/vfio_pci_intrs.c
> @@ -19,6 +19,7 @@
> #include <linux/vfio.h>
> #include <linux/wait.h>
> #include <linux/slab.h>
> +#include <linux/vfio_acpi_notify.h>
>
> #include "vfio_pci_priv.h"
>
> @@ -667,6 +668,76 @@ static int vfio_pci_set_req_trigger(struct vfio_pci_core_device *vdev,
> count, flags, data);
> }
>
> +static int
> +vfio_pci_set_acpi_ntfy_trigger(struct vfio_pci_core_device *vdev,
> + unsigned int index, unsigned int start,
> + unsigned int count, uint32_t flags, void *data)
> +{
> + struct acpi_device *adev = ACPI_COMPANION(&vdev->pdev->dev);
> + acpi_handle handle;
> +
> + if (index != VFIO_PCI_ACPI_IRQ_INDEX || start != 0 || count > 1)
> + return -EINVAL;
> +
> + if (!adev)
> + return -ENODEV;
> +
> + if (!vdev->acpi_notification)
> + return -EINVAL;
> +
> +#if IS_ENABLED(CONFIG_ACPI)
> + handle = adev->handle;
> +#endif
Seems this is only needed because vfio_acpi_notify() takes an
acpi_handle, why didn't we use the solution from
vfio_remove_acpi_notify() and pass the whole adev? vfio_acpi_notify()
could also return int and pass back an -ENOMEM since we've got the
return path. Thanks,
Alex
> +
> + /*
> + * Disable notifications: flags = (DATA_NONE|ACTION_TRIGGER), count = 0
> + * Enable loopback testing: (DATA_BOOL|ACTION_TRIGGER) or
> + * (DATA_NONE|ACTION_TRIGGER), count != 0
> + */
> + if (flags & VFIO_IRQ_SET_DATA_NONE) {
> + if (count)
> + vfio_acpi_notify(handle, ACPI_NOTIFY_DEVICE_CHECK,
> + vdev->acpi_notification);
> + else
> + vfio_remove_acpi_notify(&vdev->acpi_notification, adev);
> +
> + return 0;
> + } else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
> + uint8_t trigger;
> +
> + if (!count)
> + return -EINVAL;
> +
> + trigger = *(uint8_t *)data;
> + if (trigger)
> + vfio_acpi_notify(handle, ACPI_NOTIFY_DEVICE_CHECK,
> + vdev->acpi_notification);
> +
> + return 0;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int
> +vfio_pci_set_acpi_ntfy_eventfd_trigger(struct vfio_pci_core_device *vdev,
> + unsigned int index, unsigned int start,
> + unsigned int count, uint32_t flags, void *data)
> +{
> + struct acpi_device *adev = ACPI_COMPANION(&vdev->pdev->dev);
> + int32_t fd;
> +
> + if (index != VFIO_PCI_ACPI_IRQ_INDEX || start != 0 || count != 1)
> + return -EINVAL;
> +
> + if (!adev)
> + return -ENODEV;
> +
> + fd = *(int32_t *)data;
> +
> + return vfio_register_acpi_notify_handler(&vdev->acpi_notification, adev, fd);
> +}
> +
> int vfio_pci_set_irqs_ioctl(struct vfio_pci_core_device *vdev, uint32_t flags,
> unsigned index, unsigned start, unsigned count,
> void *data)
> @@ -716,6 +787,20 @@ int vfio_pci_set_irqs_ioctl(struct vfio_pci_core_device *vdev, uint32_t flags,
> break;
> }
> break;
> + case VFIO_PCI_ACPI_IRQ_INDEX:
> + switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
> + case VFIO_IRQ_SET_ACTION_TRIGGER:
> + switch (flags & VFIO_IRQ_SET_DATA_TYPE_MASK) {
> + case VFIO_IRQ_SET_DATA_BOOL:
> + case VFIO_IRQ_SET_DATA_NONE:
> + func = vfio_pci_set_acpi_ntfy_trigger;
> + break;
> + case VFIO_IRQ_SET_DATA_EVENTFD:
> + func = vfio_pci_set_acpi_ntfy_eventfd_trigger;
> + break;
> + }
> + }
> + break;
> }
>
> if (!func)
> diff --git a/include/linux/vfio_acpi_notify.h b/include/linux/vfio_acpi_notify.h
> new file mode 100644
> index 000000000000..4bf1d055a014
> --- /dev/null
> +++ b/include/linux/vfio_acpi_notify.h
> @@ -0,0 +1,45 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * VFIO ACPI notification replication
> + *
> + * Author: Grzegorz Jaszczyk <jaz@...ihalf.com>
> + */
> +#include <linux/acpi.h>
> +#include <linux/eventfd.h>
> +#include <linux/poll.h>
> +
> +#ifndef VFIO_ACPI_NOTIFY_H
> +#define VFIO_ACPI_NOTIFY_H
> +
> +struct vfio_acpi_notification {
> + struct eventfd_ctx *acpi_notify_trigger;
> + struct work_struct acpi_notification_work;
> + struct list_head notification_list;
> + struct mutex notification_list_lock;
> + struct mutex notification_lock;
> + int notification_queue_count;
> + poll_table pt;
> + wait_queue_entry_t wait;
> +};
> +
> +#if IS_ENABLED(CONFIG_ACPI)
> +void vfio_acpi_notify(acpi_handle handle, u32 event, void *data);
> +int vfio_register_acpi_notify_handler(struct vfio_acpi_notification **acpi_notify,
> + struct acpi_device *adev, int32_t fd);
> +void vfio_remove_acpi_notify(struct vfio_acpi_notification **acpi_notify,
> + struct acpi_device *adev);
> +#else
> +static inline void vfio_acpi_notify(acpi_handle handle, u32 event, void *data) {}
> +static inline int
> +vfio_register_acpi_notify_handler(struct vfio_acpi_notification **acpi_notify,
> + struct acpi_device *adev, int32_t fd)
> +{
> + return -ENODEV;
> +}
> +
> +static inline void
> +vfio_remove_acpi_notify(struct vfio_acpi_notification **acpi_notify,
> + struct acpi_device *adev) {}
> +#endif /* CONFIG_ACPI */
> +
> +#endif /* VFIO_ACPI_NOTIFY_H */
> diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
> index 367fd79226a3..a4491b3d8064 100644
> --- a/include/linux/vfio_pci_core.h
> +++ b/include/linux/vfio_pci_core.h
> @@ -96,6 +96,7 @@ struct vfio_pci_core_device {
> struct mutex vma_lock;
> struct list_head vma_list;
> struct rw_semaphore memory_lock;
> + struct vfio_acpi_notification *acpi_notification;
> };
>
> /* Will be exported for vfio pci drivers usage */
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index 0552e8dcf0cb..6b20ef3d202c 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -625,6 +625,7 @@ enum {
> VFIO_PCI_MSIX_IRQ_INDEX,
> VFIO_PCI_ERR_IRQ_INDEX,
> VFIO_PCI_REQ_IRQ_INDEX,
> + VFIO_PCI_ACPI_IRQ_INDEX,
> VFIO_PCI_NUM_IRQS
> };
>
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