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

Auger Eric
2019-06-07T08:30:21Z

Hi Alex,

On 6/4/19 12:32 AM, Alex Williamson wrote:
> 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.
OK, understood.

Thanks

Eric
>