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Re: [Qemu-devel] [RFC PATCH v4 3/3] VFIO Type1 IOMMU: Add support for me
From: |
Dong Jia |
Subject: |
Re: [Qemu-devel] [RFC PATCH v4 3/3] VFIO Type1 IOMMU: Add support for mediated devices |
Date: |
Wed, 1 Jun 2016 16:40:19 +0800 |
On Wed, 25 May 2016 01:28:17 +0530
Kirti Wankhede <address@hidden> wrote:
> +
> +/*
> + * Pin a set of guest PFNs and return their associated host PFNs for API
> + * supported domain only.
> + * @vaddr [in]: array of guest PFNs
> + * @npage [in]: count of array elements
> + * @prot [in] : protection flags
> + * @pfn_base[out] : array of host PFNs
> + */
> +long vfio_pin_pages(void *iommu_data, dma_addr_t *vaddr, long npage,
> + int prot, dma_addr_t *pfn_base)
> +{
> + struct vfio_iommu *iommu = iommu_data;
> + struct vfio_domain *domain = NULL;
> + int i = 0, ret = 0;
> + long retpage;
> + unsigned long remote_vaddr = 0;
> + dma_addr_t *pfn = pfn_base;
> + struct vfio_dma *dma;
> +
> + if (!iommu || !vaddr || !pfn_base)
> + return -EINVAL;
> +
> + mutex_lock(&iommu->lock);
> +
> + if (!iommu->mediated_domain) {
> + ret = -EINVAL;
> + goto pin_done;
> + }
> +
> + domain = iommu->mediated_domain;
> +
> + for (i = 0; i < npage; i++) {
> + struct vfio_pfn *p, *lpfn;
> + unsigned long tpfn;
> + dma_addr_t iova;
> + long pg_cnt = 1;
> +
> + iova = vaddr[i] << PAGE_SHIFT;
Dear Kirti:
Got one question for the vaddr-iova conversion here.
Is this a common rule that can be applied to all architectures?
AFAIK, this is wrong for the s390 case. Or I must miss something...
If the answer to the above question is 'no', should we introduce a new
argument to pass in the iovas? Say 'dma_addr_t *iova'.
> +
> + dma = vfio_find_dma(iommu, iova, 0 /* size */);
> + if (!dma) {
> + ret = -EINVAL;
> + goto pin_done;
> + }
> +
> + remote_vaddr = dma->vaddr + iova - dma->iova;
> +
> + retpage = vfio_pin_pages_internal(domain, remote_vaddr,
> + pg_cnt, prot, &tpfn);
> + if (retpage <= 0) {
> + WARN_ON(!retpage);
> + ret = (int)retpage;
> + goto pin_done;
> + }
> +
> + pfn[i] = tpfn;
> +
> + /* search if pfn exist */
> + p = vfio_find_pfn(domain, tpfn);
> + if (p) {
> + atomic_inc(&p->ref_count);
> + continue;
> + }
> +
> + /* add to pfn_list */
> + lpfn = kzalloc(sizeof(*lpfn), GFP_KERNEL);
> + if (!lpfn) {
> + ret = -ENOMEM;
> + goto pin_done;
> + }
> + lpfn->vaddr = remote_vaddr;
> + lpfn->iova = iova;
> + lpfn->pfn = pfn[i];
> + lpfn->npage = 1;
> + lpfn->prot = prot;
> + atomic_inc(&lpfn->ref_count);
> + vfio_link_pfn(domain, lpfn);
> + }
> +
> + ret = i;
> +
> +pin_done:
> + mutex_unlock(&iommu->lock);
> + return ret;
> +}
> +EXPORT_SYMBOL(vfio_pin_pages);
--------
Dong Jia
- Re: [Qemu-devel] [RFC PATCH v4 3/3] VFIO Type1 IOMMU: Add support for mediated devices,
Dong Jia <=