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Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support
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From: |
Alex Williamson |
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Subject: |
Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu |
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Date: |
Tue, 3 May 2016 16:43:06 -0600 |
On Tue, 3 May 2016 00:10:41 +0530
Kirti Wankhede <address@hidden> wrote:
> VFIO Type1 IOMMU driver is designed for the devices which are IOMMU capable.
> vGPU device are only using IOMMU TYPE1 API, the underlying hardware can be
> managed by an IOMMU domain. To use most of the code of IOMMU driver for vGPU
> devices, type1 IOMMU driver is modified to support vGPU devices. This change
> exports functions to pin and unpin pages for vGPU devices.
> It maintains data of pinned pages for vGPU domain. This data is used to verify
> unpinning request and also used to unpin pages from detach_group().
>
> Tested by assigning below combinations of devices to a single VM:
> - GPU pass through only
> - vGPU device only
> - One GPU pass through and one vGPU device
> - two GPU pass through
>
> Signed-off-by: Kirti Wankhede <address@hidden>
> Signed-off-by: Neo Jia <address@hidden>
> Change-Id: I6e35e9fc7f14049226365e9ecef3814dc4ca1738
> ---
> drivers/vfio/vfio_iommu_type1.c | 427
> ++++++++++++++++++++++++++++++++++++---
> include/linux/vfio.h | 6 +
> include/linux/vgpu.h | 4 +-
> 3 files changed, 403 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 75b24e9..a970854 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -36,6 +36,7 @@
> #include <linux/uaccess.h>
> #include <linux/vfio.h>
> #include <linux/workqueue.h>
> +#include <linux/vgpu.h>
>
> #define DRIVER_VERSION "0.2"
> #define DRIVER_AUTHOR "Alex Williamson <address@hidden>"
> @@ -67,6 +68,11 @@ struct vfio_domain {
> struct list_head group_list;
> int prot; /* IOMMU_CACHE */
> bool fgsp; /* Fine-grained super pages */
> + bool vfio_iommu_api_only; /* Domain for device
> which
> + is without physical
> IOMMU */
> + struct mm_struct *vmm_mm; /* VMM's mm */
I really don't like assuming a VMM, vfio is a userspace driver
interface, this is just an mm associated with this set of mappings.
> + struct rb_root pfn_list; /* Host pfn list for requested
> gfns */
This is just an iova to pfn list, whether it's a guest running on a
VMM, we don't care.
> + struct mutex lock; /* mutex for pfn_list */
So pfn_list_lock might be a better name for it.
> };
>
> struct vfio_dma {
> @@ -83,6 +89,19 @@ struct vfio_group {
> };
>
> /*
> + * Guest RAM pinning working set or DMA target
> + */
> +struct vfio_vgpu_pfn {
> + struct rb_node node;
> + unsigned long vmm_va; /* VMM virtual addr */
vaddr
> + dma_addr_t iova; /* IOVA */
> + unsigned long npage; /* number of pages */
> + unsigned long pfn; /* Host pfn */
> + int prot;
> + atomic_t ref_count;
> + struct list_head next;
> +};
Why is any of this vgpu specific? It's just a data structure for
tracking iova to vaddr pins.
> +/*
> * This code handles mapping and unmapping of user data buffers
> * into DMA'ble space using the IOMMU
> */
> @@ -130,6 +149,53 @@ static void vfio_unlink_dma(struct vfio_iommu *iommu,
> struct vfio_dma *old)
> rb_erase(&old->node, &iommu->dma_list);
> }
>
> +/*
> + * Helper Functions for host pfn list
> + */
> +
> +static struct vfio_vgpu_pfn *vfio_find_vgpu_pfn(struct vfio_domain *domain,
> + unsigned long pfn)
> +{
> + struct rb_node *node = domain->pfn_list.rb_node;
> +
> + while (node) {
> + struct vfio_vgpu_pfn *vgpu_pfn = rb_entry(node, struct
> vfio_vgpu_pfn, node);
> +
> + if (pfn <= vgpu_pfn->pfn)
> + node = node->rb_left;
> + else if (pfn >= vgpu_pfn->pfn)
> + node = node->rb_right;
> + else
> + return vgpu_pfn;
> + }
> +
> + return NULL;
> +}
> +
> +static void vfio_link_vgpu_pfn(struct vfio_domain *domain, struct
> vfio_vgpu_pfn *new)
> +{
> + struct rb_node **link = &domain->pfn_list.rb_node, *parent = NULL;
> + struct vfio_vgpu_pfn *vgpu_pfn;
> +
> + while (*link) {
> + parent = *link;
> + vgpu_pfn = rb_entry(parent, struct vfio_vgpu_pfn, node);
> +
> + if (new->pfn <= vgpu_pfn->pfn)
> + link = &(*link)->rb_left;
> + else
> + link = &(*link)->rb_right;
> + }
> +
> + rb_link_node(&new->node, parent, link);
> + rb_insert_color(&new->node, &domain->pfn_list);
> +}
> +
> +static void vfio_unlink_vgpu_pfn(struct vfio_domain *domain, struct
> vfio_vgpu_pfn *old)
> +{
> + rb_erase(&old->node, &domain->pfn_list);
> +}
> +
None of the above is really vgpu specific either, just managing a tree
of mappings. Name things based on what they do, not who they're for.
> struct vwork {
> struct mm_struct *mm;
> long npage;
> @@ -228,20 +294,22 @@ static int put_pfn(unsigned long pfn, int prot)
> return 0;
> }
>
> -static int vaddr_get_pfn(unsigned long vaddr, int prot, unsigned long *pfn)
> +static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
> + int prot, unsigned long *pfn)
> {
> struct page *page[1];
> struct vm_area_struct *vma;
> int ret = -EFAULT;
>
> - if (get_user_pages_fast(vaddr, 1, !!(prot & IOMMU_WRITE), page) == 1) {
> + if (get_user_pages_remote(NULL, mm, vaddr, 1, !!(prot & IOMMU_WRITE),
> + 0, page, NULL) == 1) {
AIUI, _remote requires the mmap_sem to be held, _fast does not. I don't
see that being accounted for anywhere.
> *pfn = page_to_pfn(page[0]);
> return 0;
> }
>
> - down_read(¤t->mm->mmap_sem);
> + down_read(&mm->mmap_sem);
>
> - vma = find_vma_intersection(current->mm, vaddr, vaddr + 1);
> + vma = find_vma_intersection(mm, vaddr, vaddr + 1);
>
> if (vma && vma->vm_flags & VM_PFNMAP) {
> *pfn = ((vaddr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
> @@ -249,28 +317,63 @@ static int vaddr_get_pfn(unsigned long vaddr, int prot,
> unsigned long *pfn)
> ret = 0;
> }
>
> - up_read(¤t->mm->mmap_sem);
> + up_read(&mm->mmap_sem);
>
> return ret;
> }
>
> /*
> + * Get first domain with iommu and without iommu from iommu's domain_list for
> + * lookups
> + * @iommu [in]: iommu structure
> + * @domain [out]: domain with iommu
> + * @domain_vgpu [out] : domain without iommu for vGPU
> + */
> +static void get_first_domains(struct vfio_iommu *iommu, struct vfio_domain
> **domain,
> + struct vfio_domain **domain_vgpu)
> +{
> + struct vfio_domain *d;
> +
> + if (!domain || !domain_vgpu)
> + return;
> +
> + list_for_each_entry(d, &iommu->domain_list, next) {
> + if (d->vfio_iommu_api_only && !*domain_vgpu)
> + *domain_vgpu = d;
> + else if (!*domain)
> + *domain = d;
> + if (*domain_vgpu && *domain)
> + break;
> + }
> +}
This looks like pure overhead for existing code. Also no need to
introduce the concept of vgpu here.
> +
> +/*
> * Attempt to pin pages. We really don't want to track all the pfns and
> * the iommu can only map chunks of consecutive pfns anyway, so get the
> * first page and all consecutive pages with the same locking.
> */
> -static long vfio_pin_pages(unsigned long vaddr, long npage,
> - int prot, unsigned long *pfn_base)
> +static long vfio_pin_pages_internal(void *domain_data, unsigned long vaddr,
> long npage,
I appears we know this as a struct vfio_domain in all callers, why is
this using void*?.
> + int prot, unsigned long *pfn_base)
> {
> + struct vfio_domain *domain = domain_data;
> unsigned long limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
> bool lock_cap = capable(CAP_IPC_LOCK);
> long ret, i;
> bool rsvd;
> + struct mm_struct *mm;
>
> - if (!current->mm)
> + if (!domain)
> return -ENODEV;
>
> - ret = vaddr_get_pfn(vaddr, prot, pfn_base);
> + if (domain->vfio_iommu_api_only)
> + mm = domain->vmm_mm;
> + else
> + mm = current->mm;
> +
> + if (!mm)
> + return -ENODEV;
> +
> + ret = vaddr_get_pfn(mm, vaddr, prot, pfn_base);
We could pass domain->mm unconditionally to vaddr_get_pfn(), let it be
NULL in the !api_only case and use it as a cue to vaddr_get_pfn() which
gup variant to use. Of course we need to deal with mmap_sem somewhere
too without turning the code into swiss cheese.
Correct me if I'm wrong, but I assume the main benefit of interweaving
this into type1 vs pulling out common code and making a new vfio iommu
backend is the page accounting, ie. not over accounting locked pages.
TBH, I don't know if it's worth it. Any idea what the high water mark
of pinned pages for a vgpu might be?
> if (ret)
> return ret;
>
> @@ -293,7 +396,7 @@ static long vfio_pin_pages(unsigned long vaddr, long
> npage,
> for (i = 1, vaddr += PAGE_SIZE; i < npage; i++, vaddr += PAGE_SIZE) {
> unsigned long pfn = 0;
>
> - ret = vaddr_get_pfn(vaddr, prot, &pfn);
> + ret = vaddr_get_pfn(mm, vaddr, prot, &pfn);
> if (ret)
> break;
>
> @@ -318,25 +421,183 @@ static long vfio_pin_pages(unsigned long vaddr, long
> npage,
> return i;
> }
>
> -static long vfio_unpin_pages(unsigned long pfn, long npage,
> - int prot, bool do_accounting)
> +static long vfio_unpin_pages_internal(void *domain_data, unsigned long pfn,
> long npage,
Again, all the callers seem to know they have a struct vfio_domain*, I
don't see any justification for using a void* here.
It seems less disruptive to leave these function names alone and make
the new functions _external.
> + int prot, bool do_accounting)
> {
> + struct vfio_domain *domain = domain_data;
> unsigned long unlocked = 0;
> long i;
>
> + if (!domain)
> + return -ENODEV;
> +
How is this possible? Callers of this function need to be updated for
a possible negative return or accounting gets really broken.
> for (i = 0; i < npage; i++)
> unlocked += put_pfn(pfn++, prot);
>
> if (do_accounting)
> vfio_lock_acct(-unlocked);
> + return unlocked;
> +}
> +
> +/*
> + * Pin a set of guest PFNs and return their associated host PFNs for vGPU.
> + * @vaddr [in]: array of guest PFNs
> + * @npage [in]: count of array elements
> + * @prot [in] : protection flags
> + * @pfn_base[out] : array of host PFNs
> + */
> +int 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, *domain_vgpu = NULL;
> + int i = 0, ret = 0;
> + long retpage;
> + dma_addr_t remote_vaddr = 0;
> + dma_addr_t *pfn = pfn_base;
> + struct vfio_dma *dma;
> +
> + if (!iommu || !pfn_base)
> + return -EINVAL;
> +
> + if (list_empty(&iommu->domain_list)) {
> + ret = -EINVAL;
> + goto pin_done;
> + }
> +
> + get_first_domains(iommu, &domain, &domain_vgpu);
> +
> + // Return error if vGPU domain doesn't exist
No c++ style comments please.
> + if (!domain_vgpu) {
> + ret = -EINVAL;
> + goto pin_done;
> + }
> +
> + for (i = 0; i < npage; i++) {
> + struct vfio_vgpu_pfn *p;
> + struct vfio_vgpu_pfn *lpfn;
> + unsigned long tpfn;
> + dma_addr_t iova;
> +
> + mutex_lock(&iommu->lock);
> +
> + iova = vaddr[i] << PAGE_SHIFT;
> +
> + dma = vfio_find_dma(iommu, iova, 0 /* size */);
> + if (!dma) {
> + mutex_unlock(&iommu->lock);
> + ret = -EINVAL;
> + goto pin_done;
> + }
> +
> + remote_vaddr = dma->vaddr + iova - dma->iova;
> +
> + retpage = vfio_pin_pages_internal(domain_vgpu, remote_vaddr,
> + (long)1, prot, &tpfn);
> + mutex_unlock(&iommu->lock);
> + if (retpage <= 0) {
> + WARN_ON(!retpage);
> + ret = (int)retpage;
> + goto pin_done;
> + }
> +
> + pfn[i] = tpfn;
> +
> + mutex_lock(&domain_vgpu->lock);
> +
> + // search if pfn exist
> + if ((p = vfio_find_vgpu_pfn(domain_vgpu, tpfn))) {
> + atomic_inc(&p->ref_count);
> + mutex_unlock(&domain_vgpu->lock);
> + continue;
> + }
The only reason I can come up with for why we'd want to integrate an
api-only domain into the existing type1 code would be to avoid page
accounting issues where we count locked pages once for a normal
assigned device and again for a vgpu, but that's not what we're doing
here. We're not only locking the pages again regardless of them
already being locked, we're counting every time we lock them through
this new interface. So there's really no point at all to making type1
become this unsupportable. In that case we should be pulling out the
common code that we want to share from type1 and making a new type1
compatible vfio iommu backend rather than conditionalizing everything
here.
> +
> + // add to pfn_list
> + lpfn = kzalloc(sizeof(*lpfn), GFP_KERNEL);
> + if (!lpfn) {
> + ret = -ENOMEM;
> + mutex_unlock(&domain_vgpu->lock);
> + goto pin_done;
> + }
> + lpfn->vmm_va = remote_vaddr;
> + lpfn->iova = iova;
> + lpfn->pfn = pfn[i];
> + lpfn->npage = 1;
> + lpfn->prot = prot;
> + atomic_inc(&lpfn->ref_count);
> + vfio_link_vgpu_pfn(domain_vgpu, lpfn);
> + mutex_unlock(&domain_vgpu->lock);
> + }
> +
> + ret = i;
> +
> +pin_done:
> + return ret;
> +}
> +EXPORT_SYMBOL(vfio_pin_pages);
> +
> +static int vfio_vgpu_unpin_pfn(struct vfio_domain *domain, struct
> vfio_vgpu_pfn *vpfn)
> +{
> + int ret;
> +
> + ret = vfio_unpin_pages_internal(domain, vpfn->pfn, vpfn->npage,
> vpfn->prot, true);
> +
> + if (atomic_dec_and_test(&vpfn->ref_count)) {
> + // remove from pfn_list
> + vfio_unlink_vgpu_pfn(domain, vpfn);
> + kfree(vpfn);
> + }
> +
> + return ret;
> +}
> +
> +/*
> + * Unpin set of host PFNs for vGPU.
> + * @pfn [in] : array of host PFNs to be unpinned.
> + * @npage [in] :count of elements in array, that is number of pages.
> + * @prot [in] : protection flags
> + */
> +int vfio_unpin_pages(void *iommu_data, dma_addr_t *pfn, long npage,
> + int prot)
> +{
> + struct vfio_iommu *iommu = iommu_data;
> + struct vfio_domain *domain = NULL, *domain_vgpu = NULL;
> + long unlocked = 0;
> + int i;
> + if (!iommu || !pfn)
> + return -EINVAL;
> +
> + if (list_empty(&iommu->domain_list))
> + return -EINVAL;
> +
> + get_first_domains(iommu, &domain, &domain_vgpu);
> +
> + // Return error if vGPU domain doesn't exist
> + if (!domain_vgpu)
> + return -EINVAL;
> +
> + mutex_lock(&domain_vgpu->lock);
> +
> + for (i = 0; i < npage; i++) {
> + struct vfio_vgpu_pfn *p;
> +
> + // verify if pfn exist in pfn_list
> + if (!(p = vfio_find_vgpu_pfn(domain_vgpu, *(pfn + i)))) {
> + continue;
How does the caller deal with this, the function returns number of
pages unpinned which will not match the requested number of pages to
unpin if there are any missing. Also, no setting variables within a
test when easily avoidable please, separate to a set then test.
> + }
> +
> + unlocked += vfio_vgpu_unpin_pfn(domain_vgpu, p);
> + }
> + mutex_unlock(&domain_vgpu->lock);
>
> return unlocked;
> }
> +EXPORT_SYMBOL(vfio_unpin_pages);
>
> static void vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma)
> {
> dma_addr_t iova = dma->iova, end = dma->iova + dma->size;
> - struct vfio_domain *domain, *d;
> + struct vfio_domain *domain = NULL, *d, *domain_vgpu = NULL;
> long unlocked = 0;
>
> if (!dma->size)
> @@ -348,12 +609,18 @@ static void vfio_unmap_unpin(struct vfio_iommu *iommu,
> struct vfio_dma *dma)
> * pfns to unpin. The rest need to be unmapped in advance so we have
> * no iommu translations remaining when the pages are unpinned.
> */
> - domain = d = list_first_entry(&iommu->domain_list,
> - struct vfio_domain, next);
>
> + get_first_domains(iommu, &domain, &domain_vgpu);
> +
> + if (!domain)
> + return;
> +
> + d = domain;
> list_for_each_entry_continue(d, &iommu->domain_list, next) {
> - iommu_unmap(d->domain, dma->iova, dma->size);
> - cond_resched();
> + if (!d->vfio_iommu_api_only) {
> + iommu_unmap(d->domain, dma->iova, dma->size);
> + cond_resched();
> + }
> }
>
> while (iova < end) {
How do api-only domain not blowup on the iommu API code in this next
code block? Are you just getting lucky that the api-only domain is
first in the list and the real domain is last?
> @@ -382,7 +649,7 @@ static void vfio_unmap_unpin(struct vfio_iommu *iommu,
> struct vfio_dma *dma)
> if (WARN_ON(!unmapped))
> break;
>
> - unlocked += vfio_unpin_pages(phys >> PAGE_SHIFT,
> + unlocked += vfio_unpin_pages_internal(domain, phys >>
> PAGE_SHIFT,
> unmapped >> PAGE_SHIFT,
> dma->prot, false);
> iova += unmapped;
> @@ -406,8 +673,10 @@ static unsigned long vfio_pgsize_bitmap(struct
> vfio_iommu *iommu)
> unsigned long bitmap = ULONG_MAX;
>
> mutex_lock(&iommu->lock);
> - list_for_each_entry(domain, &iommu->domain_list, next)
> - bitmap &= domain->domain->ops->pgsize_bitmap;
> + list_for_each_entry(domain, &iommu->domain_list, next) {
> + if (!domain->vfio_iommu_api_only)
> + bitmap &= domain->domain->ops->pgsize_bitmap;
> + }
> mutex_unlock(&iommu->lock);
>
> /*
> @@ -517,6 +786,9 @@ static int map_try_harder(struct vfio_domain *domain,
> dma_addr_t iova,
> long i;
> int ret;
>
> + if (domain->vfio_iommu_api_only)
> + return -EINVAL;
> +
> for (i = 0; i < npage; i++, pfn++, iova += PAGE_SIZE) {
> ret = iommu_map(domain->domain, iova,
> (phys_addr_t)pfn << PAGE_SHIFT,
> @@ -538,6 +810,9 @@ static int vfio_iommu_map(struct vfio_iommu *iommu,
> dma_addr_t iova,
> int ret;
>
> list_for_each_entry(d, &iommu->domain_list, next) {
> + if (d->vfio_iommu_api_only)
> + continue;
> +
Really disliking all these switches everywhere, too many different code
paths.
> ret = iommu_map(d->domain, iova, (phys_addr_t)pfn << PAGE_SHIFT,
> npage << PAGE_SHIFT, prot | d->prot);
> if (ret) {
> @@ -552,8 +827,11 @@ static int vfio_iommu_map(struct vfio_iommu *iommu,
> dma_addr_t iova,
> return 0;
>
> unwind:
> - list_for_each_entry_continue_reverse(d, &iommu->domain_list, next)
> + list_for_each_entry_continue_reverse(d, &iommu->domain_list, next) {
> + if (d->vfio_iommu_api_only)
> + continue;
> iommu_unmap(d->domain, iova, npage << PAGE_SHIFT);
> + }
>
> return ret;
> }
> @@ -569,6 +847,8 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
> uint64_t mask;
> struct vfio_dma *dma;
> unsigned long pfn;
> + struct vfio_domain *domain = NULL;
> + int domain_with_iommu_present = 0;
>
> /* Verify that none of our __u64 fields overflow */
> if (map->size != size || map->vaddr != vaddr || map->iova != iova)
> @@ -611,9 +891,22 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
> /* Insert zero-sized and grow as we map chunks of it */
> vfio_link_dma(iommu, dma);
>
> + list_for_each_entry(domain, &iommu->domain_list, next) {
> + if (!domain->vfio_iommu_api_only) {
> + domain_with_iommu_present = 1;
> + break;
> + }
> + }
> +
> + // Skip pin and map only if domain without IOMMU is present
> + if (!domain_with_iommu_present) {
> + dma->size = size;
> + goto map_done;
> + }
> +
Yet more special cases, the code is getting unsupportable.
> while (size) {
> /* Pin a contiguous chunk of memory */
> - npage = vfio_pin_pages(vaddr + dma->size,
> + npage = vfio_pin_pages_internal(domain, vaddr + dma->size,
> size >> PAGE_SHIFT, prot, &pfn);
> if (npage <= 0) {
> WARN_ON(!npage);
> @@ -623,8 +916,8 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
>
> /* Map it! */
> ret = vfio_iommu_map(iommu, iova + dma->size, pfn, npage, prot);
> - if (ret) {
> - vfio_unpin_pages(pfn, npage, prot, true);
> + if (ret){
> + vfio_unpin_pages_internal(domain, pfn, npage, prot,
> true);
> break;
> }
>
> @@ -635,6 +928,7 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
> if (ret)
> vfio_remove_dma(iommu, dma);
>
> +map_done:
> mutex_unlock(&iommu->lock);
> return ret;
> }
> @@ -654,12 +948,15 @@ static int vfio_bus_type(struct device *dev, void *data)
> static int vfio_iommu_replay(struct vfio_iommu *iommu,
> struct vfio_domain *domain)
> {
> - struct vfio_domain *d;
> + struct vfio_domain *d = NULL, *d_vgpu = NULL;
> struct rb_node *n;
> int ret;
>
> + if (domain->vfio_iommu_api_only)
> + return -EINVAL;
Huh? This only does iommu API stuff, shouldn't we skip it w/o error
for api-only?
> +
> /* Arbitrarily pick the first domain in the list for lookups */
> - d = list_first_entry(&iommu->domain_list, struct vfio_domain, next);
> + get_first_domains(iommu, &d, &d_vgpu);
Gag, probably should have used a separate list.
> n = rb_first(&iommu->dma_list);
>
> /* If there's not a domain, there better not be any mappings */
> @@ -716,6 +1013,9 @@ static void vfio_test_domain_fgsp(struct vfio_domain
> *domain)
> struct page *pages;
> int ret, order = get_order(PAGE_SIZE * 2);
>
> + if (domain->vfio_iommu_api_only)
> + return;
> +
> pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
> if (!pages)
> return;
> @@ -769,6 +1069,23 @@ static int vfio_iommu_type1_attach_group(void
> *iommu_data,
> if (ret)
> goto out_free;
>
> + if (!iommu_present(bus) && (bus == &vgpu_bus_type)) {
> + struct vgpu_device *vgpu_dev = NULL;
> +
> + vgpu_dev = get_vgpu_device_from_group(iommu_group);
> + if (!vgpu_dev)
> + goto out_free;
> +
> + vgpu_dev->iommu_data = iommu;
Probably better to have a vgpu_set_iommu_data() function rather than
manipulate it ourselves. We also have no guarantees about races since
vgpus have no reference counting.
> + domain->vfio_iommu_api_only = true;
> + domain->vmm_mm = current->mm;
> + INIT_LIST_HEAD(&domain->group_list);
> + list_add(&group->next, &domain->group_list);
> + domain->pfn_list = RB_ROOT;
> + mutex_init(&domain->lock);
> + goto out_success;
> + }
Very little sharing going on here.
> +
> domain->domain = iommu_domain_alloc(bus);
> if (!domain->domain) {
> ret = -EIO;
> @@ -834,6 +1151,7 @@ static int vfio_iommu_type1_attach_group(void
> *iommu_data,
> if (ret)
> goto out_detach;
>
> +out_success:
> list_add(&domain->next, &iommu->domain_list);
>
> mutex_unlock(&iommu->lock);
> @@ -854,11 +1172,36 @@ out_free:
> static void vfio_iommu_unmap_unpin_all(struct vfio_iommu *iommu)
> {
> struct rb_node *node;
> + struct vfio_domain *domain = NULL, *domain_vgpu = NULL;
> +
> + get_first_domains(iommu, &domain, &domain_vgpu);
> +
> + if (domain_vgpu) {
> + int unlocked;
> + mutex_lock(&domain_vgpu->lock);
> + while ((node = rb_first(&domain_vgpu->pfn_list))) {
> + unlocked = vfio_vgpu_unpin_pfn(domain_vgpu,
> + rb_entry(node, struct vfio_vgpu_pfn,
> node));
Why bother to store the return?
> + }
> + mutex_unlock(&domain_vgpu->lock);
> + }
>
> while ((node = rb_first(&iommu->dma_list)))
> vfio_remove_dma(iommu, rb_entry(node, struct vfio_dma, node));
> }
>
> +static bool list_is_singular_iommu_domain(struct vfio_iommu *iommu)
> +{
> + struct vfio_domain *domain;
> + int domain_iommu = 0;
> +
> + list_for_each_entry(domain, &iommu->domain_list, next) {
> + if (!domain->vfio_iommu_api_only)
> + domain_iommu++;
> + }
> + return (domain_iommu == 1);
> +}
> +
> static void vfio_iommu_type1_detach_group(void *iommu_data,
> struct iommu_group *iommu_group)
> {
> @@ -872,19 +1215,28 @@ static void vfio_iommu_type1_detach_group(void
> *iommu_data,
> list_for_each_entry(group, &domain->group_list, next) {
> if (group->iommu_group != iommu_group)
> continue;
> + if (!domain->vfio_iommu_api_only)
> + iommu_detach_group(domain->domain, iommu_group);
> + else {
> + struct vgpu_device *vgpu_dev = NULL;
>
> - iommu_detach_group(domain->domain, iommu_group);
> + vgpu_dev =
> get_vgpu_device_from_group(iommu_group);
> + if (vgpu_dev)
> + vgpu_dev->iommu_data = NULL;
> +
> + }
> list_del(&group->next);
> kfree(group);
> /*
> * Group ownership provides privilege, if the group
> * list is empty, the domain goes away. If it's the
> - * last domain, then all the mappings go away too.
> + * last domain with iommu, then all the mappings go
> away too.
> */
> if (list_empty(&domain->group_list)) {
> - if (list_is_singular(&iommu->domain_list))
> + if (list_is_singular_iommu_domain(iommu))
> vfio_iommu_unmap_unpin_all(iommu);
> - iommu_domain_free(domain->domain);
> + if (!domain->vfio_iommu_api_only)
> + iommu_domain_free(domain->domain);
> list_del(&domain->next);
> kfree(domain);
> }
> @@ -936,11 +1288,22 @@ static void vfio_iommu_type1_release(void *iommu_data)
> &iommu->domain_list, next) {
> list_for_each_entry_safe(group, group_tmp,
> &domain->group_list, next) {
> - iommu_detach_group(domain->domain, group->iommu_group);
> + if (!domain->vfio_iommu_api_only)
> + iommu_detach_group(domain->domain,
> group->iommu_group);
> + else {
> + struct vgpu_device *vgpu_dev = NULL;
> +
> + vgpu_dev =
> get_vgpu_device_from_group(group->iommu_group);
> + if (vgpu_dev)
> + vgpu_dev->iommu_data = NULL;
> +
> + }
> +
> list_del(&group->next);
> kfree(group);
> }
> - iommu_domain_free(domain->domain);
> + if (!domain->vfio_iommu_api_only)
> + iommu_domain_free(domain->domain);
> list_del(&domain->next);
> kfree(domain);
> }
I'm really not convinced that pushing this into the type1 code is the
right approach vs pulling out shareable code chunks where it makes
sense and creating a separate iommu backend. We're not getting
anything but code complexity out of this approach it seems. Thanks,
Alex
> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> index 0ecae0b..d280868 100644
> --- a/include/linux/vfio.h
> +++ b/include/linux/vfio.h
> @@ -127,6 +127,12 @@ static inline long vfio_spapr_iommu_eeh_ioctl(struct
> iommu_group *group,
> }
> #endif /* CONFIG_EEH */
>
> +extern long vfio_pin_pages(void *iommu_data, dma_addr_t *vaddr, long npage,
> + int prot, dma_addr_t *pfn_base);
> +
> +extern long vfio_unpin_pages(void *iommu_data, dma_addr_t *pfn, long npage,
> + int prot);
> +
> /*
> * IRQfd - generic
> */
> diff --git a/include/linux/vgpu.h b/include/linux/vgpu.h
> index 03a77cf..cc18353 100644
> --- a/include/linux/vgpu.h
> +++ b/include/linux/vgpu.h
> @@ -36,6 +36,7 @@ struct vgpu_device {
> struct device dev;
> struct gpu_device *gpu_dev;
> struct iommu_group *group;
> + void *iommu_data;
> #define DEVICE_NAME_LEN (64)
> char dev_name[DEVICE_NAME_LEN];
> uuid_le uuid;
> @@ -209,8 +210,7 @@ extern void vgpu_unregister_driver(struct vgpu_driver
> *drv);
>
> extern int vgpu_map_virtual_bar(uint64_t virt_bar_addr, uint64_t
> phys_bar_addr,
> uint32_t len, uint32_t flags);
> -extern int vgpu_dma_do_translate(dma_addr_t * gfn_buffer, uint32_t count);
>
> -struct vgpu_device *get_vgpu_device_from_group(struct iommu_group *group);
> +extern struct vgpu_device *get_vgpu_device_from_group(struct iommu_group
> *group);
>
> #endif /* VGPU_H */
- Re: [Qemu-devel] [RFC PATCH v3 1/3] vGPU Core driver, (continued)
- Re: [Qemu-devel] [RFC PATCH v3 1/3] vGPU Core driver, Tian, Kevin, 2016/05/05
- Re: [Qemu-devel] [RFC PATCH v3 1/3] vGPU Core driver, Kirti Wankhede, 2016/05/05
- Re: [Qemu-devel] [RFC PATCH v3 1/3] vGPU Core driver, Tian, Kevin, 2016/05/05
- Re: [Qemu-devel] [RFC PATCH v3 1/3] vGPU Core driver, Kirti Wankhede, 2016/05/05
- Re: [Qemu-devel] [RFC PATCH v3 1/3] vGPU Core driver, Tian, Kevin, 2016/05/11
- Re: [Qemu-devel] [RFC PATCH v3 1/3] vGPU Core driver, Jike Song, 2016/05/06
- Re: [Qemu-devel] [RFC PATCH v3 1/3] vGPU Core driver, Kirti Wankhede, 2016/05/06
- Re: [Qemu-devel] [RFC PATCH v3 1/3] vGPU Core driver, Jike Song, 2016/05/09
[Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Kirti Wankhede, 2016/05/02
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Jike Song, 2016/05/03
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu,
Alex Williamson <=
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Tian, Kevin, 2016/05/03
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Jike Song, 2016/05/05
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Tian, Kevin, 2016/05/05
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Jike Song, 2016/05/10
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Neo Jia, 2016/05/10
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Jike Song, 2016/05/11
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Alex Williamson, 2016/05/11
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Jike Song, 2016/05/12
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Neo Jia, 2016/05/12
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Tian, Kevin, 2016/05/12