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

Vikas Gupta
2021-01-15T06:27:53Z

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Hi Eric,

On Tue, Jan 12, 2021 at 2:30 PM Auger Eric <eric.auger@redhat.com> 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@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?
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.

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)
> >>> *
> >>>
> >>
> >