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

Auger Eric
2021-01-12T09:02:43Z

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@redhat.com> 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@broadcom.com>
>>> ---
>>> 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?

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?

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.

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)
>>> *
>>>
>>
>