Re: [PATCH v8 24/29] vfio: VFIO_IOMMU_BIND/UNBIND_MSI

Alex Williamson
2019-06-03T22:32:43Z

On Sun, 26 May 2019 18:09:59 +0200
Eric Auger <eric.auger@redhat.com> wrote:

> This patch adds the VFIO_IOMMU_BIND/UNBIND_MSI ioctl which aim
> to pass/withdraw the guest MSI binding to/from the host.
>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>
> ---
> v6 -> v7:
> - removed the dev arg
>
> v3 -> v4:
> - add UNBIND
> - unwind on BIND error
>
> v2 -> v3:
> - adapt to new proto of bind_guest_msi
> - directly use vfio_iommu_for_each_dev
>
> v1 -> v2:
> - s/vfio_iommu_type1_guest_msi_binding/vfio_iommu_type1_bind_guest_msi
> ---
> drivers/vfio/vfio_iommu_type1.c | 64 +++++++++++++++++++++++++++++++++
> include/uapi/linux/vfio.h | 29 +++++++++++++++
> 2 files changed, 93 insertions(+)
>
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 6fda4fbc9bfa..18142cb078a3 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -1832,6 +1832,42 @@ static int vfio_cache_inv_fn(struct device *dev, void *data)
> return iommu_cache_invalidate(dc->domain, dev, &ustruct->info);
> }
>
> +static int
> +vfio_bind_msi(struct vfio_iommu *iommu,
> + dma_addr_t giova, phys_addr_t gpa, size_t size)
> +{
> + struct vfio_domain *d;
> + int ret = 0;
> +
> + mutex_lock(&iommu->lock);
> +
> + list_for_each_entry(d, &iommu->domain_list, next) {
> + ret = iommu_bind_guest_msi(d->domain, giova, gpa, size);
> + if (ret)
> + goto unwind;
> + }
> + goto unlock;
> +unwind:
> + list_for_each_entry_continue_reverse(d, &iommu->domain_list, next) {
> + iommu_unbind_guest_msi(d->domain, giova);
> + }
> +unlock:
> + mutex_unlock(&iommu->lock);
> + return ret;
> +}
> +
> +static void
> +vfio_unbind_msi(struct vfio_iommu *iommu, dma_addr_t giova)
> +{
> + struct vfio_domain *d;
> +
> + mutex_lock(&iommu->lock);
> + list_for_each_entry(d, &iommu->domain_list, next) {
> + iommu_unbind_guest_msi(d->domain, giova);
> + }
> + mutex_unlock(&iommu->lock);
> +}
> +
> static long vfio_iommu_type1_ioctl(void *iommu_data,
> unsigned int cmd, unsigned long arg)
> {
> @@ -1936,6 +1972,34 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
> &ustruct);
> mutex_unlock(&iommu->lock);
> return ret;
> + } else if (cmd == VFIO_IOMMU_BIND_MSI) {
> + struct vfio_iommu_type1_bind_msi ustruct;
> +
> + minsz = offsetofend(struct vfio_iommu_type1_bind_msi,
> + size);
> +
> + if (copy_from_user(&ustruct, (void __user *)arg, minsz))
> + return -EFAULT;
> +
> + if (ustruct.argsz < minsz || ustruct.flags)
> + return -EINVAL;
> +
> + return vfio_bind_msi(iommu, ustruct.iova, ustruct.gpa,
> + ustruct.size);
> + } else if (cmd == VFIO_IOMMU_UNBIND_MSI) {
> + struct vfio_iommu_type1_unbind_msi ustruct;
> +
> + minsz = offsetofend(struct vfio_iommu_type1_unbind_msi,
> + iova);
> +
> + if (copy_from_user(&ustruct, (void __user *)arg, minsz))
> + return -EFAULT;
> +
> + if (ustruct.argsz < minsz || ustruct.flags)
> + return -EINVAL;
> +
> + vfio_unbind_msi(iommu, ustruct.iova);
> + return 0;
> }
>
> return -ENOTTY;
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index 055aa9b9745a..2774a1ab37ae 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -798,6 +798,35 @@ struct vfio_iommu_type1_cache_invalidate {
> };
> #define VFIO_IOMMU_CACHE_INVALIDATE _IO(VFIO_TYPE, VFIO_BASE + 24)
>
> +/**
> + * VFIO_IOMMU_BIND_MSI - _IOWR(VFIO_TYPE, VFIO_BASE + 25,
> + * struct vfio_iommu_type1_bind_msi)
> + *
> + * Pass a stage 1 MSI doorbell mapping to the host so that this
> + * latter can build a nested stage2 mapping
> + */
> +struct vfio_iommu_type1_bind_msi {
> + __u32 argsz;
> + __u32 flags;
> + __u64 iova;
> + __u64 gpa;
> + __u64 size;
> +};
> +#define VFIO_IOMMU_BIND_MSI _IO(VFIO_TYPE, VFIO_BASE + 25)
> +
> +/**
> + * VFIO_IOMMU_UNBIND_MSI - _IOWR(VFIO_TYPE, VFIO_BASE + 26,
> + * struct vfio_iommu_type1_unbind_msi)
> + *
> + * Unregister an MSI mapping
> + */
> +struct vfio_iommu_type1_unbind_msi {
> + __u32 argsz;
> + __u32 flags;
> + __u64 iova;
> +};
> +#define VFIO_IOMMU_UNBIND_MSI _IO(VFIO_TYPE, VFIO_BASE + 26)
> +
> /* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */
>
> /*

And another pair of ioctls. Maybe think about how we can reduce the
ioctl bloat of this series. I don't want to impose an awkward
interface for the sake of fewer ioctls, but I also don't want us
casually burning through ioctls.