Re: [RFC v3 1/2] vfio/platform: add support for msi

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Hi Vikas,

On 1/15/21 7:26 AM, Vikas Gupta wrote:
> Hi Eric,
> 
> On Tue, Jan 12, 2021 at 2:30 PM Auger Eric <eric.auger@xxxxxxxxxx> wrote:
>>
>> Hi Vikas,
>>
>> On 1/5/21 6:53 AM, Vikas Gupta wrote:
>>> On Tue, Dec 22, 2020 at 10:57 PM Auger Eric <eric.auger@xxxxxxxxxx> wrote:
>>>>
>>>> Hi Vikas,
>>>>
>>>> On 12/14/20 6:45 PM, Vikas Gupta wrote:
>>>>> MSI support for platform devices.The MSI block
>>>>> is added as an extended IRQ which exports caps
>>>>> VFIO_IRQ_INFO_CAP_TYPE and VFIO_IRQ_INFO_CAP_MSI_DESCS.
>>>>>
>>>>> Signed-off-by: Vikas Gupta <vikas.gupta@xxxxxxxxxxxx>
>>>>> ---
>>>>>  drivers/vfio/platform/vfio_platform_common.c  | 179 +++++++++++-
>>>>>  drivers/vfio/platform/vfio_platform_irq.c     | 260 +++++++++++++++++-
>>>>>  drivers/vfio/platform/vfio_platform_private.h |  32 +++
>>>>>  include/uapi/linux/vfio.h                     |  44 +++
>>>>>  4 files changed, 496 insertions(+), 19 deletions(-)
>>>>>
>>>>> diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
>>>>> index fb4b385191f2..c936852f35d7 100644
>>>>> --- a/drivers/vfio/platform/vfio_platform_common.c
>>>>> +++ b/drivers/vfio/platform/vfio_platform_common.c
>>>>> @@ -16,6 +16,7 @@
>>>>>  #include <linux/types.h>
>>>>>  #include <linux/uaccess.h>
>>>>>  #include <linux/vfio.h>
>>>>> +#include <linux/nospec.h>
>>>>>
>>>>>  #include "vfio_platform_private.h"
>>>>>
>>>>> @@ -26,6 +27,8 @@
>>>>>  #define VFIO_PLATFORM_IS_ACPI(vdev) ((vdev)->acpihid != NULL)
>>>>>
>>>>>  static LIST_HEAD(reset_list);
>>>>> +/* devices having MSI support */
>>>> nit: for devices using MSIs?
>>>>> +static LIST_HEAD(msi_list);
>>>>>  static DEFINE_MUTEX(driver_lock);
>>>>>
>>>>>  static vfio_platform_reset_fn_t vfio_platform_lookup_reset(const char *compat,
>>>>> @@ -47,6 +50,25 @@ static vfio_platform_reset_fn_t vfio_platform_lookup_reset(const char *compat,
>>>>>       return reset_fn;
>>>>>  }
>>>>>
>>>>> +static bool vfio_platform_lookup_msi(struct vfio_platform_device *vdev)
>>>>> +{
>>>>> +     bool has_msi = false;
>>>>> +     struct vfio_platform_msi_node *iter;
>>>>> +
>>>>> +     mutex_lock(&driver_lock);
>>>>> +     list_for_each_entry(iter, &msi_list, link) {
>>>>> +             if (!strcmp(iter->compat, vdev->compat) &&
>>>>> +                 try_module_get(iter->owner)) {
>>>>> +                     vdev->msi_module = iter->owner;
>>>>> +                     vdev->of_get_msi = iter->of_get_msi;
>>>>> +                     has_msi = true;
>>>>> +                     break;
>>>>> +             }
>>>>> +     }
>>>>> +     mutex_unlock(&driver_lock);
>>>>> +     return has_msi;
>>>>> +}
>>>>> +
>>>>>  static int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
>>>>>                                   struct device *dev)
>>>>>  {
>>>>> @@ -126,6 +148,19 @@ static int vfio_platform_get_reset(struct vfio_platform_device *vdev)
>>>>>       return vdev->of_reset ? 0 : -ENOENT;
>>>>>  }
>>>>>
>>>>> +static int vfio_platform_get_msi(struct vfio_platform_device *vdev)
>>>>> +{
>>>>> +     bool has_msi;
>>>>> +
>>>>> +     has_msi = vfio_platform_lookup_msi(vdev);
>>>>> +     if (!has_msi) {
>>>>> +             request_module("vfio-msi:%s", vdev->compat);
>>>>> +             has_msi = vfio_platform_lookup_msi(vdev);
>>>>> +     }
>>>>> +
>>>>> +     return has_msi ? 0 : -ENOENT;
>>>>> +}
>>>>> +
>>>>>  static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
>>>>>  {
>>>>>       if (VFIO_PLATFORM_IS_ACPI(vdev))
>>>>> @@ -135,6 +170,12 @@ static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
>>>>>               module_put(vdev->reset_module);
>>>>>  }
>>>>>
>>>>> +static void vfio_platform_put_msi(struct vfio_platform_device *vdev)
>>>>> +{
>>>>> +     if (vdev->of_get_msi)
>>>>> +             module_put(vdev->msi_module);
>>>>> +}
>>>>> +
>>>>>  static int vfio_platform_regions_init(struct vfio_platform_device *vdev)
>>>>>  {
>>>>>       int cnt = 0, i;
>>>>> @@ -343,9 +384,17 @@ static long vfio_platform_ioctl(void *device_data,
>>>>>
>>>>>       } else if (cmd == VFIO_DEVICE_GET_IRQ_INFO) {
>>>>>               struct vfio_irq_info info;
>>>>> +             struct vfio_info_cap caps = { .buf = NULL, .size = 0 };
>>>>> +             struct vfio_irq_info_cap_msi *msi_info = NULL;
>>>>> +             int ext_irq_index = vdev->num_irqs - vdev->num_ext_irqs;
>>>>> +             unsigned long capsz;
>>>>> +             u32 index;
>>>>>
>>>>>               minsz = offsetofend(struct vfio_irq_info, count);
>>>>>
>>>>> +             /* For backward compatibility, cannot require this */
>>>>> +             capsz = offsetofend(struct vfio_irq_info, cap_offset);
>>>>> +
>>>>>               if (copy_from_user(&info, (void __user *)arg, minsz))
>>>>>                       return -EFAULT;
>>>>>
>>>>> @@ -355,8 +404,94 @@ static long vfio_platform_ioctl(void *device_data,
>>>>>               if (info.index >= vdev->num_irqs)
>>>>>                       return -EINVAL;
>>>>>
>>>>> -             info.flags = vdev->irqs[info.index].flags;
>>>>> -             info.count = vdev->irqs[info.index].count;
>>>>> +             if (info.argsz >= capsz)
>>>>> +                     minsz = capsz;
>>>>> +
>>>>> +             index = info.index;
>>>>> +
>>>>> +             info.flags = vdev->irqs[index].flags;
>>>>> +             info.count = vdev->irqs[index].count;
>>>>> +
>>>>> +             if (ext_irq_index - index == VFIO_EXT_IRQ_MSI) {
>>>>> +                     struct vfio_irq_info_cap_type cap_type = {
>>>>> +                             .header.id = VFIO_IRQ_INFO_CAP_TYPE,
>>>>> +                             .header.version = 1 };
>>>>> +                     struct vfio_platform_irq *irq;
>>>>> +                     size_t msi_info_size;
>>>>> +                     int num_msgs;
>>>>> +                     int ret;
>>>>> +                     int i;
>>>>> +
>>>>> +                     index = array_index_nospec(index,
>>>>> +                                                vdev->num_irqs);
>>>>> +                     irq = &vdev->irqs[index];
>>>>> +
>>>>> +                     cap_type.type = irq->type;
>>>>> +                     cap_type.subtype = irq->subtype;
>>>>> +
>>>>> +                     ret = vfio_info_add_capability(&caps,
>>>>> +                                                    &cap_type.header,
>>>>> +                                                    sizeof(cap_type));
>>>>> +                     if (ret)
>>>>> +                             return ret;
>>>>> +
>>>>> +                     num_msgs = irq->num_ctx;
>>>>> +                     if (num_msgs) {
>>>>> +                             msi_info_size = struct_size(msi_info,
>>>>> +                                                         msgs, num_msgs);
>>>>> +
>>>>> +                             msi_info = kzalloc(msi_info_size, GFP_KERNEL);
>>>>> +                             if (!msi_info) {
>>>>> +                                     kfree(caps.buf);
>>>>> +                                     return -ENOMEM;
>>>>> +                             }
>>>>> +
>>>>> +                             msi_info->header.id =
>>>>> +                                             VFIO_IRQ_INFO_CAP_MSI_DESCS;
>>>> I thought you would remove this cap now the module is back. What is the
>>>> motivation to keep it?
>>>
>>> Hi Eric,
>>> The earlier module was serving two purposes
>>> a)   Max number of MSI(s) supported by the device. Since the module is
>>> back this information can be filled in .count.
>> understood
>>> b)   Writing msi_msg(s) to devices for MSI sources.
>>>  We want b) to be handled in the user space so that they need not be
>>> dependent on the kernel.
>> I fail to understand the problem with the "dependency on the kernel".
>> What is the functional difference when exposing this to the userspace,
>> please could you highlight the benefits?
> We do not see any functional difference here, the benefit we see is
> that user space can configure MSI sources with msi_msg rather than
> doing it in the kernel.
> 
>>
>>  VFIO_IRQ_INFO_CAP_MSI_DESCS is helping user
>>> space to get MSI configuration data and thus they can independently
>>> configure MSI sources. For example, user space can just ask for ‘N’
>>> MSI vectors and related msi_msg for ‘N’ vectors
>> this is induced by vfio_msi_enable(), right?
>>
> Yes
>>
>>  is exported to user
>>> space using this CAP. User space can now use ‘N’ vectors to configure
>>> any ‘N’ MSI sources and these sources might be in any order.
>>> However, this design is different from vfio-pci as MSI configuration
>>> is being handled in kernel only.
>>> Let us know if implementing VFIO_IRQ_INFO_CAP_MSI_DESCS does not fit
>>> with the CAP framework.
>> I think it is OK reporting them through the cap but I fail to understand
>> the benefits.
> 
> I believe, since there is no significant benefit this CAP should be
> avoided. I plan to remove this CAP in the next patch set.

OK thank you for the confirmation.

Thanks

Eric
> 
> Thanks,
> Vikas
>>
>> Thanks
>>
>> Eric
>>>
>>> Thanks,
>>> Vikas
>>>
>>>  >
>>>> Thanks
>>>>
>>>> Eric
>>>>> +                             msi_info->header.version = 1;
>>>>> +                             msi_info->nr_msgs = num_msgs;
>>>>> +
>>>>> +                             for (i = 0; i < num_msgs; i++) {
>>>>> +                                     struct vfio_irq_ctx *ctx = &irq->ctx[i];
>>>>> +
>>>>> +                                     msi_info->msgs[i].addr_lo =
>>>>> +                                                     ctx->msg.address_lo;
>>>>> +                                     msi_info->msgs[i].addr_hi =
>>>>> +                                                     ctx->msg.address_hi;
>>>>> +                                     msi_info->msgs[i].data = ctx->msg.data;
>>>>> +                             }
>>>>> +
>>>>> +                             ret = vfio_info_add_capability(&caps,
>>>>> +                                                     &msi_info->header,
>>>>> +                                                     msi_info_size);
>>>>> +                             if (ret) {
>>>>> +                                     kfree(msi_info);
>>>>> +                                     kfree(caps.buf);
>>>>> +                                     return ret;
>>>>> +                             }
>>>>> +                     }
>>>>> +             }
>>>>> +
>>>>> +             if (caps.size) {
>>>>> +                     info.flags |= VFIO_IRQ_INFO_FLAG_CAPS;
>>>>> +                     if (info.argsz < sizeof(info) + caps.size) {
>>>>> +                             info.argsz = sizeof(info) + caps.size;
>>>>> +                             info.cap_offset = 0;
>>>>> +                     } else {
>>>>> +                             vfio_info_cap_shift(&caps, sizeof(info));
>>>>> +                             if (copy_to_user((void __user *)arg +
>>>>> +                                               sizeof(info), caps.buf,
>>>>> +                                               caps.size)) {
>>>>> +                                     kfree(msi_info);
>>>>> +                                     kfree(caps.buf);
>>>>> +                                     return -EFAULT;
>>>>> +                             }
>>>>> +                             info.cap_offset = sizeof(info);
>>>>> +                     }
>>>>> +
>>>>> +                     kfree(msi_info);
>>>>> +                     kfree(caps.buf);
>>>>> +             }
>>>>>
>>>>>               return copy_to_user((void __user *)arg, &info, minsz) ?
>>>>>                       -EFAULT : 0;
>>>>> @@ -365,6 +500,7 @@ static long vfio_platform_ioctl(void *device_data,
>>>>>               struct vfio_irq_set hdr;
>>>>>               u8 *data = NULL;
>>>>>               int ret = 0;
>>>>> +             int max;
>>>>>               size_t data_size = 0;
>>>>>
>>>>>               minsz = offsetofend(struct vfio_irq_set, count);
>>>>> @@ -372,8 +508,14 @@ static long vfio_platform_ioctl(void *device_data,
>>>>>               if (copy_from_user(&hdr, (void __user *)arg, minsz))
>>>>>                       return -EFAULT;
>>>>>
>>>>> -             ret = vfio_set_irqs_validate_and_prepare(&hdr, vdev->num_irqs,
>>>>> -                                              vdev->num_irqs, &data_size);
>>>>> +             if (hdr.index >= vdev->num_irqs)
>>>>> +                     return -EINVAL;
>>>>> +
>>>>> +             max = vdev->irqs[hdr.index].count;
>>>>> +
>>>>> +             ret = vfio_set_irqs_validate_and_prepare(&hdr, max,
>>>>> +                                                      vdev->num_irqs,
>>>>> +                                                      &data_size);
>>>>>               if (ret)
>>>>>                       return ret;
>>>>>
>>>>> @@ -678,6 +820,10 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev,
>>>>>               return ret;
>>>>>       }
>>>>>
>>>>> +     ret = vfio_platform_get_msi(vdev);
>>>>> +     if (ret)
>>>>> +             dev_info(vdev->device, "msi not supported\n");
>>>> I don't think we should output this message. This is printed for
>>>> amd-xgbe which does not have msi so this is misleading. I would say
>>>> either the vfio_platform_get_msi() can return an actual error or we
>>>> return a void?
>>> Will check on this what
>>>>
>>>> Thanks
>>>>
>>>> Eric
>>>>> +
>>>>>       group = vfio_iommu_group_get(dev);
>>>>>       if (!group) {
>>>>>               dev_err(dev, "No IOMMU group for device %s\n", vdev->name);
>>>>> @@ -697,6 +843,7 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev,
>>>>>  put_iommu:
>>>>>       vfio_iommu_group_put(group, dev);
>>>>>  put_reset:
>>>>> +     vfio_platform_put_msi(vdev);
>>>>>       vfio_platform_put_reset(vdev);
>>>>>       return ret;
>>>>>  }
>>>>> @@ -744,6 +891,30 @@ void vfio_platform_unregister_reset(const char *compat,
>>>>>  }
>>>>>  EXPORT_SYMBOL_GPL(vfio_platform_unregister_reset);
>>>>>
>>>>> +void __vfio_platform_register_msi(struct vfio_platform_msi_node *node)
>>>>> +{
>>>>> +     mutex_lock(&driver_lock);
>>>>> +     list_add(&node->link, &msi_list);
>>>>> +     mutex_unlock(&driver_lock);
>>>>> +}
>>>>> +EXPORT_SYMBOL_GPL(__vfio_platform_register_msi);
>>>>> +
>>>>> +void vfio_platform_unregister_msi(const char *compat)
>>>>> +{
>>>>> +     struct vfio_platform_msi_node *iter, *temp;
>>>>> +
>>>>> +     mutex_lock(&driver_lock);
>>>>> +     list_for_each_entry_safe(iter, temp, &msi_list, link) {
>>>>> +             if (!strcmp(iter->compat, compat)) {
>>>>> +                     list_del(&iter->link);
>>>>> +                     break;
>>>>> +             }
>>>>> +     }
>>>>> +
>>>>> +     mutex_unlock(&driver_lock);
>>>>> +}
>>>>> +EXPORT_SYMBOL_GPL(vfio_platform_unregister_msi);
>>>>> +
>>>>>  MODULE_VERSION(DRIVER_VERSION);
>>>>>  MODULE_LICENSE("GPL v2");
>>>>>  MODULE_AUTHOR(DRIVER_AUTHOR);
>>>>> diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
>>>>> index c5b09ec0a3c9..e0f4696afedd 100644
>>>>> --- a/drivers/vfio/platform/vfio_platform_irq.c
>>>>> +++ b/drivers/vfio/platform/vfio_platform_irq.c
>>>>> @@ -8,10 +8,12 @@
>>>>>
>>>>>  #include <linux/eventfd.h>
>>>>>  #include <linux/interrupt.h>
>>>>> +#include <linux/eventfd.h>
>>>>>  #include <linux/slab.h>
>>>>>  #include <linux/types.h>
>>>>>  #include <linux/vfio.h>
>>>>>  #include <linux/irq.h>
>>>>> +#include <linux/msi.h>
>>>>>
>>>>>  #include "vfio_platform_private.h"
>>>>>
>>>>> @@ -253,6 +255,195 @@ static int vfio_platform_set_irq_trigger(struct vfio_platform_device *vdev,
>>>>>       return 0;
>>>>>  }
>>>>>
>>>>> +/* MSI/MSIX */
>>>>> +static irqreturn_t vfio_msihandler(int irq, void *arg)
>>>>> +{
>>>>> +     struct eventfd_ctx *trigger = arg;
>>>>> +
>>>>> +     eventfd_signal(trigger, 1);
>>>>> +     return IRQ_HANDLED;
>>>>> +}
>>>>> +
>>>>> +static void msi_write(struct msi_desc *desc, struct msi_msg *msg)
>>>>> +{
>>>>> +     int i;
>>>>> +     struct vfio_platform_irq *irq;
>>>>> +     u16 index = desc->platform.msi_index;
>>>>> +     struct device *dev = msi_desc_to_dev(desc);
>>>>> +     struct vfio_device *device = dev_get_drvdata(dev);
>>>>> +     struct vfio_platform_device *vdev = (struct vfio_platform_device *)
>>>>> +                                             vfio_device_data(device);
>>>>> +
>>>>> +     for (i = 0; i < vdev->num_irqs; i++)
>>>>> +             if (vdev->irqs[i].type == VFIO_IRQ_TYPE_MSI)
>>>>> +                     irq = &vdev->irqs[i];
>>>>> +
>>>>> +     irq->ctx[index].msg.address_lo = msg->address_lo;
>>>>> +     irq->ctx[index].msg.address_hi = msg->address_hi;
>>>>> +     irq->ctx[index].msg.data = msg->data;
>>>>> +}
>>>>> +
>>>>> +static int vfio_msi_enable(struct vfio_platform_device *vdev,
>>>>> +                        struct vfio_platform_irq *irq, int nvec)
>>>>> +{
>>>>> +     int ret;
>>>>> +     int msi_idx = 0;
>>>>> +     struct msi_desc *desc;
>>>>> +     struct device *dev = vdev->device;
>>>>> +
>>>>> +     irq->ctx = kcalloc(nvec, sizeof(struct vfio_irq_ctx), GFP_KERNEL);
>>>>> +     if (!irq->ctx)
>>>>> +             return -ENOMEM;
>>>>> +
>>>>> +     /* Allocate platform MSIs */
>>>>> +     ret = platform_msi_domain_alloc_irqs(dev, nvec, msi_write);
>>>>> +     if (ret < 0) {
>>>>> +             kfree(irq->ctx);
>>>>> +             return ret;
>>>>> +     }
>>>>> +
>>>>> +     for_each_msi_entry(desc, dev) {
>>>>> +             irq->ctx[msi_idx].hwirq = desc->irq;
>>>>> +             msi_idx++;
>>>>> +     }
>>>>> +
>>>>> +     irq->num_ctx = nvec;
>>>>> +     irq->config_msi = 1;
>>>>> +
>>>>> +     return 0;
>>>>> +}
>>>>> +
>>>>> +static int vfio_msi_set_vector_signal(struct vfio_platform_irq *irq,
>>>>> +                                   int vector, int fd)
>>>>> +{
>>>>> +     struct eventfd_ctx *trigger;
>>>>> +     int irq_num, ret;
>>>>> +
>>>>> +     if (vector < 0 || vector >= irq->num_ctx)
>>>>> +             return -EINVAL;
>>>>> +
>>>>> +     irq_num = irq->ctx[vector].hwirq;
>>>>> +
>>>>> +     if (irq->ctx[vector].trigger) {
>>>>> +             free_irq(irq_num, irq->ctx[vector].trigger);
>>>>> +             kfree(irq->ctx[vector].name);
>>>>> +             eventfd_ctx_put(irq->ctx[vector].trigger);
>>>>> +             irq->ctx[vector].trigger = NULL;
>>>>> +     }
>>>>> +
>>>>> +     if (fd < 0)
>>>>> +             return 0;
>>>>> +
>>>>> +     irq->ctx[vector].name = kasprintf(GFP_KERNEL,
>>>>> +                                       "vfio-msi[%d]", vector);
>>>>> +     if (!irq->ctx[vector].name)
>>>>> +             return -ENOMEM;
>>>>> +
>>>>> +     trigger = eventfd_ctx_fdget(fd);
>>>>> +     if (IS_ERR(trigger)) {
>>>>> +             kfree(irq->ctx[vector].name);
>>>>> +             return PTR_ERR(trigger);
>>>>> +     }
>>>>> +
>>>>> +     ret = request_irq(irq_num, vfio_msihandler, 0,
>>>>> +                       irq->ctx[vector].name, trigger);
>>>>> +     if (ret) {
>>>>> +             kfree(irq->ctx[vector].name);
>>>>> +             eventfd_ctx_put(trigger);
>>>>> +             return ret;
>>>>> +     }
>>>>> +
>>>>> +     irq->ctx[vector].trigger = trigger;
>>>>> +
>>>>> +     return 0;
>>>>> +}
>>>>> +
>>>>> +static int vfio_msi_set_block(struct vfio_platform_irq *irq, unsigned int start,
>>>>> +                           unsigned int count, int32_t *fds)
>>>>> +{
>>>>> +     int i, j, ret = 0;
>>>>> +
>>>>> +     if (start >= irq->num_ctx || start + count > irq->num_ctx)
>>>>> +             return -EINVAL;
>>>>> +
>>>>> +     for (i = 0, j = start; i < count && !ret; i++, j++) {
>>>>> +             int fd = fds ? fds[i] : -1;
>>>>> +
>>>>> +             ret = vfio_msi_set_vector_signal(irq, j, fd);
>>>>> +     }
>>>>> +
>>>>> +     if (ret) {
>>>>> +             for (--j; j >= (int)start; j--)
>>>>> +                     vfio_msi_set_vector_signal(irq, j, -1);
>>>>> +     }
>>>>> +
>>>>> +     return ret;
>>>>> +}
>>>>> +
>>>>> +static void vfio_msi_disable(struct vfio_platform_device *vdev,
>>>>> +                          struct vfio_platform_irq *irq)
>>>>> +{
>>>>> +     struct device *dev = vdev->device;
>>>>> +
>>>>> +     vfio_msi_set_block(irq, 0, irq->num_ctx, NULL);
>>>>> +
>>>>> +     platform_msi_domain_free_irqs(dev);
>>>>> +
>>>>> +     irq->config_msi = 0;
>>>>> +     irq->num_ctx = 0;
>>>>> +
>>>>> +     kfree(irq->ctx);
>>>>> +}
>>>>> +
>>>>> +static int vfio_set_msi_trigger(struct vfio_platform_device *vdev,
>>>>> +                             unsigned int index, unsigned int start,
>>>>> +                             unsigned int count, uint32_t flags, void *data)
>>>>> +{
>>>>> +     int i;
>>>>> +     struct vfio_platform_irq *irq = &vdev->irqs[index];
>>>>> +
>>>>> +     if (start + count > irq->count)
>>>>> +             return -EINVAL;
>>>>> +
>>>>> +     if (!count && (flags & VFIO_IRQ_SET_DATA_NONE)) {
>>>>> +             vfio_msi_disable(vdev, irq);
>>>>> +             return 0;
>>>>> +     }
>>>>> +
>>>>> +     if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
>>>>> +             s32 *fds = data;
>>>>> +             int ret;
>>>>> +
>>>>> +             if (irq->config_msi)
>>>>> +                     return vfio_msi_set_block(irq, start, count,
>>>>> +                                               fds);
>>>>> +             ret = vfio_msi_enable(vdev, irq, start + count);
>>>>> +             if (ret)
>>>>> +                     return ret;
>>>>> +
>>>>> +             ret = vfio_msi_set_block(irq, start, count, fds);
>>>>> +             if (ret)
>>>>> +                     vfio_msi_disable(vdev, irq);
>>>>> +
>>>>> +             return ret;
>>>>> +     }
>>>>> +
>>>>> +     for (i = start; i < start + count; i++) {
>>>>> +             if (!irq->ctx[i].trigger)
>>>>> +                     continue;
>>>>> +             if (flags & VFIO_IRQ_SET_DATA_NONE) {
>>>>> +                     eventfd_signal(irq->ctx[i].trigger, 1);
>>>>> +             } else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
>>>>> +                     u8 *bools = data;
>>>>> +
>>>>> +                     if (bools[i - start])
>>>>> +                             eventfd_signal(irq->ctx[i].trigger, 1);
>>>>> +             }
>>>>> +     }
>>>>> +
>>>>> +     return 0;
>>>>> +}
>>>>> +
>>>>>  int vfio_platform_set_irqs_ioctl(struct vfio_platform_device *vdev,
>>>>>                                uint32_t flags, unsigned index, unsigned start,
>>>>>                                unsigned count, void *data)
>>>>> @@ -261,16 +452,29 @@ int vfio_platform_set_irqs_ioctl(struct vfio_platform_device *vdev,
>>>>>                   unsigned start, unsigned count, uint32_t flags,
>>>>>                   void *data) = NULL;
>>>>>
>>>>> -     switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
>>>>> -     case VFIO_IRQ_SET_ACTION_MASK:
>>>>> -             func = vfio_platform_set_irq_mask;
>>>>> -             break;
>>>>> -     case VFIO_IRQ_SET_ACTION_UNMASK:
>>>>> -             func = vfio_platform_set_irq_unmask;
>>>>> -             break;
>>>>> -     case VFIO_IRQ_SET_ACTION_TRIGGER:
>>>>> -             func = vfio_platform_set_irq_trigger;
>>>>> -             break;
>>>>> +     struct vfio_platform_irq *irq = &vdev->irqs[index];
>>>>> +
>>>>> +     if (irq->type == VFIO_IRQ_TYPE_MSI) {
>>>>> +             switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
>>>>> +             case VFIO_IRQ_SET_ACTION_MASK:
>>>>> +             case VFIO_IRQ_SET_ACTION_UNMASK:
>>>>> +                     break;
>>>>> +             case VFIO_IRQ_SET_ACTION_TRIGGER:
>>>>> +                     func = vfio_set_msi_trigger;
>>>>> +                     break;
>>>>> +             }
>>>>> +     } else {
>>>>> +             switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
>>>>> +             case VFIO_IRQ_SET_ACTION_MASK:
>>>>> +                     func = vfio_platform_set_irq_mask;
>>>>> +                     break;
>>>>> +             case VFIO_IRQ_SET_ACTION_UNMASK:
>>>>> +                     func = vfio_platform_set_irq_unmask;
>>>>> +                     break;
>>>>> +             case VFIO_IRQ_SET_ACTION_TRIGGER:
>>>>> +                     func = vfio_platform_set_irq_trigger;
>>>>> +                     break;
>>>>> +             }
>>>>>       }
>>>>>
>>>>>       if (!func)
>>>>> @@ -281,12 +485,21 @@ int vfio_platform_set_irqs_ioctl(struct vfio_platform_device *vdev,
>>>>>
>>>>>  int vfio_platform_irq_init(struct vfio_platform_device *vdev)
>>>>>  {
>>>>> -     int cnt = 0, i;
>>>>> +     int i;
>>>>> +     int cnt = 0;
>>>>> +     int num_irqs;
>>>>> +     int msi_cnt = 0;
>>>>>
>>>>>       while (vdev->get_irq(vdev, cnt) >= 0)
>>>>>               cnt++;
>>>>>
>>>>> -     vdev->irqs = kcalloc(cnt, sizeof(struct vfio_platform_irq), GFP_KERNEL);
>>>>> +     if (vdev->of_get_msi) {
>>>>> +             msi_cnt = vdev->of_get_msi(vdev);
>>>>> +             num_irqs++;
>>>>> +     }
>>>>> +
>>>>> +     vdev->irqs = kcalloc(num_irqs, sizeof(struct vfio_platform_irq),
>>>>> +                          GFP_KERNEL);
>>>>>       if (!vdev->irqs)
>>>>>               return -ENOMEM;
>>>>>
>>>>> @@ -309,7 +522,19 @@ int vfio_platform_irq_init(struct vfio_platform_device *vdev)
>>>>>               vdev->irqs[i].masked = false;
>>>>>       }
>>>>>
>>>>> -     vdev->num_irqs = cnt;
>>>>> +     /*
>>>>> +      * MSI block is added at last index and it is an ext irq
>>>>> +      */
>>>>> +     if (msi_cnt > 0) {
>>>>> +             vdev->irqs[i].flags = VFIO_IRQ_INFO_EVENTFD;
>>>>> +             vdev->irqs[i].count = msi_cnt;
>>>>> +             vdev->irqs[i].hwirq = 0;
>>>>> +             vdev->irqs[i].masked = false;
>>>>> +             vdev->irqs[i].type = VFIO_IRQ_TYPE_MSI;
>>>>> +             vdev->num_ext_irqs = 1;
>>>>> +     }
>>>>> +
>>>>> +     vdev->num_irqs = num_irqs;
>>>>>
>>>>>       return 0;
>>>>>  err:
>>>>> @@ -321,8 +546,13 @@ void vfio_platform_irq_cleanup(struct vfio_platform_device *vdev)
>>>>>  {
>>>>>       int i;
>>>>>
>>>>> -     for (i = 0; i < vdev->num_irqs; i++)
>>>>> -             vfio_set_trigger(vdev, i, -1, NULL);
>>>>> +     for (i = 0; i < vdev->num_irqs; i++) {
>>>>> +             if (vdev->irqs[i].type == VFIO_IRQ_TYPE_MSI)
>>>>> +                     vfio_set_msi_trigger(vdev, i, 0, 0,
>>>>> +                                          VFIO_IRQ_SET_DATA_NONE, NULL);
>>>>> +             else
>>>>> +                     vfio_set_trigger(vdev, i, -1, NULL);
>>>>> +     }
>>>>>
>>>>>       vdev->num_irqs = 0;
>>>>>       kfree(vdev->irqs);
>>>>> diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
>>>>> index 289089910643..1307feddda21 100644
>>>>> --- a/drivers/vfio/platform/vfio_platform_private.h
>>>>> +++ b/drivers/vfio/platform/vfio_platform_private.h
>>>>> @@ -9,6 +9,7 @@
>>>>>
>>>>>  #include <linux/types.h>
>>>>>  #include <linux/interrupt.h>
>>>>> +#include <linux/msi.h>
>>>>>
>>>>>  #define VFIO_PLATFORM_OFFSET_SHIFT   40
>>>>>  #define VFIO_PLATFORM_OFFSET_MASK (((u64)(1) << VFIO_PLATFORM_OFFSET_SHIFT) - 1)
>>>>> @@ -19,9 +20,21 @@
>>>>>  #define VFIO_PLATFORM_INDEX_TO_OFFSET(index) \
>>>>>       ((u64)(index) << VFIO_PLATFORM_OFFSET_SHIFT)
>>>>>
>>>>> +/* IRQ index for MSI in ext IRQs */
>>>>> +#define VFIO_EXT_IRQ_MSI     0
>>>>> +
>>>>> +struct vfio_irq_ctx {
>>>>> +     int                     hwirq;
>>>>> +     char                    *name;
>>>>> +     struct msi_msg          msg;
>>>>> +     struct eventfd_ctx      *trigger;
>>>>> +};
>>>>> +
>>>>>  struct vfio_platform_irq {
>>>>>       u32                     flags;
>>>>>       u32                     count;
>>>>> +     int                     num_ctx;
>>>>> +     struct vfio_irq_ctx     *ctx;
>>>>>       int                     hwirq;
>>>>>       char                    *name;
>>>>>       struct eventfd_ctx      *trigger;
>>>>> @@ -29,6 +42,11 @@ struct vfio_platform_irq {
>>>>>       spinlock_t              lock;
>>>>>       struct virqfd           *unmask;
>>>>>       struct virqfd           *mask;
>>>>> +
>>>>> +     /* for extended irqs */
>>>>> +     u32                     type;
>>>>> +     u32                     subtype;
>>>>> +     int                     config_msi;
>>>>>  };
>>>>>
>>>>>  struct vfio_platform_region {
>>>>> @@ -46,12 +64,14 @@ struct vfio_platform_device {
>>>>>       u32                             num_regions;
>>>>>       struct vfio_platform_irq        *irqs;
>>>>>       u32                             num_irqs;
>>>>> +     int                             num_ext_irqs;
>>>>>       int                             refcnt;
>>>>>       struct mutex                    igate;
>>>>>       struct module                   *parent_module;
>>>>>       const char                      *compat;
>>>>>       const char                      *acpihid;
>>>>>       struct module                   *reset_module;
>>>>> +     struct module                   *msi_module;
>>>>>       struct device                   *device;
>>>>>
>>>>>       /*
>>>>> @@ -65,11 +85,13 @@ struct vfio_platform_device {
>>>>>               (*get_resource)(struct vfio_platform_device *vdev, int i);
>>>>>       int     (*get_irq)(struct vfio_platform_device *vdev, int i);
>>>>>       int     (*of_reset)(struct vfio_platform_device *vdev);
>>>>> +     u32     (*of_get_msi)(struct vfio_platform_device *vdev);
>>>>>
>>>>>       bool                            reset_required;
>>>>>  };
>>>>>
>>>>>  typedef int (*vfio_platform_reset_fn_t)(struct vfio_platform_device *vdev);
>>>>> +typedef u32 (*vfio_platform_get_msi_fn_t)(struct vfio_platform_device *vdev);
>>>>>
>>>>>  struct vfio_platform_reset_node {
>>>>>       struct list_head link;
>>>>> @@ -78,6 +100,13 @@ struct vfio_platform_reset_node {
>>>>>       vfio_platform_reset_fn_t of_reset;
>>>>>  };
>>>>>
>>>>> +struct vfio_platform_msi_node {
>>>>> +     struct list_head link;
>>>>> +     char *compat;
>>>>> +     struct module *owner;
>>>>> +     vfio_platform_get_msi_fn_t of_get_msi;
>>>>> +};
>>>>> +
>>>>>  extern int vfio_platform_probe_common(struct vfio_platform_device *vdev,
>>>>>                                     struct device *dev);
>>>>>  extern struct vfio_platform_device *vfio_platform_remove_common
>>>>> @@ -94,6 +123,9 @@ extern int vfio_platform_set_irqs_ioctl(struct vfio_platform_device *vdev,
>>>>>  extern void __vfio_platform_register_reset(struct vfio_platform_reset_node *n);
>>>>>  extern void vfio_platform_unregister_reset(const char *compat,
>>>>>                                          vfio_platform_reset_fn_t fn);
>>>>> +void __vfio_platform_register_msi(struct vfio_platform_msi_node *n);
>>>>> +void vfio_platform_unregister_msi(const char *compat);
>>>>> +
>>>>>  #define vfio_platform_register_reset(__compat, __reset)              \
>>>>>  static struct vfio_platform_reset_node __reset ## _node = {  \
>>>>>       .owner = THIS_MODULE,                                   \
>>>>> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
>>>>> index d1812777139f..53a7ff2b524e 100644
>>>>> --- a/include/uapi/linux/vfio.h
>>>>> +++ b/include/uapi/linux/vfio.h
>>>>> @@ -697,11 +697,55 @@ struct vfio_irq_info {
>>>>>  #define VFIO_IRQ_INFO_MASKABLE               (1 << 1)
>>>>>  #define VFIO_IRQ_INFO_AUTOMASKED     (1 << 2)
>>>>>  #define VFIO_IRQ_INFO_NORESIZE               (1 << 3)
>>>>> +#define VFIO_IRQ_INFO_FLAG_CAPS              (1 << 4) /* Info supports caps */
>>>>>       __u32   index;          /* IRQ index */
>>>>>       __u32   count;          /* Number of IRQs within this index */
>>>>> +     __u32   cap_offset;     /* Offset within info struct of first cap */
>>>>>  };
>>>>>  #define VFIO_DEVICE_GET_IRQ_INFO     _IO(VFIO_TYPE, VFIO_BASE + 9)
>>>>>
>>>>> +/*
>>>>> + * The irq type capability allows IRQs unique to a specific device or
>>>>> + * class of devices to be exposed.
>>>>> + *
>>>>> + * The structures below define version 1 of this capability.
>>>>> + */
>>>>> +#define VFIO_IRQ_INFO_CAP_TYPE               3
>>>>> +
>>>>> +struct vfio_irq_info_cap_type {
>>>>> +     struct vfio_info_cap_header header;
>>>>> +     __u32 type;     /* global per bus driver */
>>>>> +     __u32 subtype;  /* type specific */
>>>>> +};
>>>>> +
>>>>> +/*
>>>>> + * List of IRQ types, global per bus driver.
>>>>> + * If you introduce a new type, please add it here.
>>>>> + */
>>>>> +
>>>>> +/* Non PCI devices having MSI(s) support */
>>>>> +#define VFIO_IRQ_TYPE_MSI            (1)
>>>>> +
>>>>> +/*
>>>>> + * The msi capability allows the user to use the msi msg to
>>>>> + * configure the iova for the msi configuration.
>>>>> + * The structures below define version 1 of this capability.
>>>>> + */
>>>>> +#define VFIO_IRQ_INFO_CAP_MSI_DESCS  4
>>>>> +
>>>>> +struct vfio_irq_msi_msg {
>>>>> +     __u32   addr_lo;
>>>>> +     __u32   addr_hi;
>>>>> +     __u32   data;
>>>>> +};
>>>>> +
>>>>> +struct vfio_irq_info_cap_msi {
>>>>> +     struct vfio_info_cap_header header;
>>>>> +     __u32   nr_msgs;
>>>>> +     __u32   reserved;
>>>>> +     struct vfio_irq_msi_msg msgs[];
>>>>> +};
>>>>> +
>>>>>  /**
>>>>>   * VFIO_DEVICE_SET_IRQS - _IOW(VFIO_TYPE, VFIO_BASE + 10, struct vfio_irq_set)
>>>>>   *
>>>>>
>>>>
>>>
>>




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