On Tue, Mar 29, 2022 at 01:37:52PM +0800, Lu Baolu wrote:
> @@ -95,6 +101,7 @@ struct iommu_domain {
> void *handler_token;
> struct iommu_domain_geometry geometry;
> struct iommu_dma_cookie *iova_cookie;
> + struct iommu_sva_cookie *sva_cookie;
Cookie is still the wrong word to use here
> +struct iommu_sva_cookie {
> + struct mm_struct *mm;
> + ioasid_t pasid;
> + refcount_t users;
Really surprised to see a refcount buried inside the iommu_domain..
This design seems inside out, the SVA struct should 'enclose' the domain, not
be a pointer inside it.
struct iommu_sva_domain {
struct kref_t kref;
struct mm_struct *mm;
ioasid_t pasid;
/* All the domains that are linked to this */
struct xarray domain_list;
};
And then you could have a pointer to that inside the mm_struct instead
of just the naked pasid.
> +static __maybe_unused struct iommu_domain *
Why maybe unused?
> +iommu_sva_get_domain(struct device *dev, struct mm_struct *mm)
> +{
> + struct iommu_domain *domain;
> + ioasid_t pasid = mm->pasid;
> +
> + if (pasid == INVALID_IOASID)
> + return NULL;
> +
> + domain = xa_load(&sva_domain_array, pasid);
> + if (!domain)
> + return iommu_sva_alloc_domain(dev, mm);
> + iommu_sva_domain_get_user(domain);
This assumes any domain is interchangeable with any device, which is
not the iommu model. We need a domain op to check if a device is
compatiable with the domain for vfio an iommufd, this should do the
same.
It means each mm can have a list of domains associated with it and a
new domain is auto-created if the device doesn't work with any of the
existing domains.
Jason
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