Commit 8f0d5bb9 authored by Kirti Wankhede's avatar Kirti Wankhede Committed by Alex Williamson

vfio iommu type1: Add task structure to vfio_dma

Add task structure to vfio_dma structure. Task structure is used for:
- During DMA_UNMAP, same task who mapped it or other task who shares same
address space is allowed to unmap, otherwise unmap fails.
QEMU maps few iova ranges initially, then fork threads and from the child
thread calls DMA_UNMAP on previously mapped iova. Since child shares same
address space, DMA_UNMAP is successful.
- Avoid accessing struct mm while process is exiting by acquiring
reference of task's mm during page accounting.
- It is also used to get task mlock capability and rlimit for mlock.
Signed-off-by: default avatarKirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: default avatarNeo Jia <cjia@nvidia.com>
Reviewed-by: default avatarDong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 7896c998
...@@ -36,6 +36,7 @@ ...@@ -36,6 +36,7 @@
#include <linux/uaccess.h> #include <linux/uaccess.h>
#include <linux/vfio.h> #include <linux/vfio.h>
#include <linux/workqueue.h> #include <linux/workqueue.h>
#include <linux/pid_namespace.h>
#define DRIVER_VERSION "0.2" #define DRIVER_VERSION "0.2"
#define DRIVER_AUTHOR "Alex Williamson <alex.williamson@redhat.com>" #define DRIVER_AUTHOR "Alex Williamson <alex.williamson@redhat.com>"
...@@ -75,6 +76,7 @@ struct vfio_dma { ...@@ -75,6 +76,7 @@ struct vfio_dma {
unsigned long vaddr; /* Process virtual addr */ unsigned long vaddr; /* Process virtual addr */
size_t size; /* Map size (bytes) */ size_t size; /* Map size (bytes) */
int prot; /* IOMMU_READ/WRITE */ int prot; /* IOMMU_READ/WRITE */
struct task_struct *task;
}; };
struct vfio_group { struct vfio_group {
...@@ -277,41 +279,47 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr, ...@@ -277,41 +279,47 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
* the iommu can only map chunks of consecutive pfns anyway, so get the * the iommu can only map chunks of consecutive pfns anyway, so get the
* first page and all consecutive pages with the same locking. * first page and all consecutive pages with the same locking.
*/ */
static long vfio_pin_pages_remote(unsigned long vaddr, long npage, static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
int prot, unsigned long *pfn_base) long npage, int prot, unsigned long *pfn_base)
{ {
unsigned long limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; unsigned long limit;
bool lock_cap = capable(CAP_IPC_LOCK); bool lock_cap = ns_capable(task_active_pid_ns(dma->task)->user_ns,
CAP_IPC_LOCK);
struct mm_struct *mm;
long ret, i; long ret, i;
bool rsvd; bool rsvd;
if (!current->mm) mm = get_task_mm(dma->task);
if (!mm)
return -ENODEV; return -ENODEV;
ret = vaddr_get_pfn(current->mm, vaddr, prot, pfn_base); ret = vaddr_get_pfn(mm, vaddr, prot, pfn_base);
if (ret) if (ret)
return ret; goto pin_pg_remote_exit;
rsvd = is_invalid_reserved_pfn(*pfn_base); rsvd = is_invalid_reserved_pfn(*pfn_base);
limit = task_rlimit(dma->task, RLIMIT_MEMLOCK) >> PAGE_SHIFT;
if (!rsvd && !lock_cap && current->mm->locked_vm + 1 > limit) { if (!rsvd && !lock_cap && mm->locked_vm + 1 > limit) {
put_pfn(*pfn_base, prot); put_pfn(*pfn_base, prot);
pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n", __func__, pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n", __func__,
limit << PAGE_SHIFT); limit << PAGE_SHIFT);
return -ENOMEM; ret = -ENOMEM;
goto pin_pg_remote_exit;
} }
if (unlikely(disable_hugepages)) { if (unlikely(disable_hugepages)) {
if (!rsvd) if (!rsvd)
vfio_lock_acct(current, 1); vfio_lock_acct(dma->task, 1);
return 1; ret = 1;
goto pin_pg_remote_exit;
} }
/* Lock all the consecutive pages from pfn_base */ /* Lock all the consecutive pages from pfn_base */
for (i = 1, vaddr += PAGE_SIZE; i < npage; i++, vaddr += PAGE_SIZE) { for (i = 1, vaddr += PAGE_SIZE; i < npage; i++, vaddr += PAGE_SIZE) {
unsigned long pfn = 0; unsigned long pfn = 0;
ret = vaddr_get_pfn(current->mm, vaddr, prot, &pfn); ret = vaddr_get_pfn(mm, vaddr, prot, &pfn);
if (ret) if (ret)
break; break;
...@@ -321,8 +329,7 @@ static long vfio_pin_pages_remote(unsigned long vaddr, long npage, ...@@ -321,8 +329,7 @@ static long vfio_pin_pages_remote(unsigned long vaddr, long npage,
break; break;
} }
if (!rsvd && !lock_cap && if (!rsvd && !lock_cap && mm->locked_vm + i + 1 > limit) {
current->mm->locked_vm + i + 1 > limit) {
put_pfn(pfn, prot); put_pfn(pfn, prot);
pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n", pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n",
__func__, limit << PAGE_SHIFT); __func__, limit << PAGE_SHIFT);
...@@ -331,13 +338,16 @@ static long vfio_pin_pages_remote(unsigned long vaddr, long npage, ...@@ -331,13 +338,16 @@ static long vfio_pin_pages_remote(unsigned long vaddr, long npage,
} }
if (!rsvd) if (!rsvd)
vfio_lock_acct(current, i); vfio_lock_acct(dma->task, i);
ret = i;
return i; pin_pg_remote_exit:
mmput(mm);
return ret;
} }
static long vfio_unpin_pages_remote(unsigned long pfn, long npage, static long vfio_unpin_pages_remote(struct vfio_dma *dma, unsigned long pfn,
int prot, bool do_accounting) long npage, int prot, bool do_accounting)
{ {
unsigned long unlocked = 0; unsigned long unlocked = 0;
long i; long i;
...@@ -346,7 +356,7 @@ static long vfio_unpin_pages_remote(unsigned long pfn, long npage, ...@@ -346,7 +356,7 @@ static long vfio_unpin_pages_remote(unsigned long pfn, long npage,
unlocked += put_pfn(pfn++, prot); unlocked += put_pfn(pfn++, prot);
if (do_accounting) if (do_accounting)
vfio_lock_acct(current, -unlocked); vfio_lock_acct(dma->task, -unlocked);
return unlocked; return unlocked;
} }
...@@ -400,7 +410,7 @@ static void vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma) ...@@ -400,7 +410,7 @@ static void vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma)
if (WARN_ON(!unmapped)) if (WARN_ON(!unmapped))
break; break;
unlocked += vfio_unpin_pages_remote(phys >> PAGE_SHIFT, unlocked += vfio_unpin_pages_remote(dma, phys >> PAGE_SHIFT,
unmapped >> PAGE_SHIFT, unmapped >> PAGE_SHIFT,
dma->prot, false); dma->prot, false);
iova += unmapped; iova += unmapped;
...@@ -408,13 +418,14 @@ static void vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma) ...@@ -408,13 +418,14 @@ static void vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma)
cond_resched(); cond_resched();
} }
vfio_lock_acct(current, -unlocked); vfio_lock_acct(dma->task, -unlocked);
} }
static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma) static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
{ {
vfio_unmap_unpin(iommu, dma); vfio_unmap_unpin(iommu, dma);
vfio_unlink_dma(iommu, dma); vfio_unlink_dma(iommu, dma);
put_task_struct(dma->task);
kfree(dma); kfree(dma);
} }
...@@ -510,6 +521,12 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu, ...@@ -510,6 +521,12 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
while ((dma = vfio_find_dma(iommu, unmap->iova, unmap->size))) { while ((dma = vfio_find_dma(iommu, unmap->iova, unmap->size))) {
if (!iommu->v2 && unmap->iova > dma->iova) if (!iommu->v2 && unmap->iova > dma->iova)
break; break;
/*
* Task with same address space who mapped this iova range is
* allowed to unmap the iova range.
*/
if (dma->task->mm != current->mm)
break;
unmapped += dma->size; unmapped += dma->size;
vfio_remove_dma(iommu, dma); vfio_remove_dma(iommu, dma);
} }
...@@ -576,17 +593,55 @@ static int vfio_iommu_map(struct vfio_iommu *iommu, dma_addr_t iova, ...@@ -576,17 +593,55 @@ static int vfio_iommu_map(struct vfio_iommu *iommu, dma_addr_t iova,
return ret; return ret;
} }
static int vfio_pin_map_dma(struct vfio_iommu *iommu, struct vfio_dma *dma,
size_t map_size)
{
dma_addr_t iova = dma->iova;
unsigned long vaddr = dma->vaddr;
size_t size = map_size;
long npage;
unsigned long pfn;
int ret = 0;
while (size) {
/* Pin a contiguous chunk of memory */
npage = vfio_pin_pages_remote(dma, vaddr + dma->size,
size >> PAGE_SHIFT, dma->prot,
&pfn);
if (npage <= 0) {
WARN_ON(!npage);
ret = (int)npage;
break;
}
/* Map it! */
ret = vfio_iommu_map(iommu, iova + dma->size, pfn, npage,
dma->prot);
if (ret) {
vfio_unpin_pages_remote(dma, pfn, npage,
dma->prot, true);
break;
}
size -= npage << PAGE_SHIFT;
dma->size += npage << PAGE_SHIFT;
}
if (ret)
vfio_remove_dma(iommu, dma);
return ret;
}
static int vfio_dma_do_map(struct vfio_iommu *iommu, static int vfio_dma_do_map(struct vfio_iommu *iommu,
struct vfio_iommu_type1_dma_map *map) struct vfio_iommu_type1_dma_map *map)
{ {
dma_addr_t iova = map->iova; dma_addr_t iova = map->iova;
unsigned long vaddr = map->vaddr; unsigned long vaddr = map->vaddr;
size_t size = map->size; size_t size = map->size;
long npage;
int ret = 0, prot = 0; int ret = 0, prot = 0;
uint64_t mask; uint64_t mask;
struct vfio_dma *dma; struct vfio_dma *dma;
unsigned long pfn;
/* Verify that none of our __u64 fields overflow */ /* Verify that none of our __u64 fields overflow */
if (map->size != size || map->vaddr != vaddr || map->iova != iova) if (map->size != size || map->vaddr != vaddr || map->iova != iova)
...@@ -612,47 +667,27 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu, ...@@ -612,47 +667,27 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
mutex_lock(&iommu->lock); mutex_lock(&iommu->lock);
if (vfio_find_dma(iommu, iova, size)) { if (vfio_find_dma(iommu, iova, size)) {
mutex_unlock(&iommu->lock); ret = -EEXIST;
return -EEXIST; goto out_unlock;
} }
dma = kzalloc(sizeof(*dma), GFP_KERNEL); dma = kzalloc(sizeof(*dma), GFP_KERNEL);
if (!dma) { if (!dma) {
mutex_unlock(&iommu->lock); ret = -ENOMEM;
return -ENOMEM; goto out_unlock;
} }
dma->iova = iova; dma->iova = iova;
dma->vaddr = vaddr; dma->vaddr = vaddr;
dma->prot = prot; dma->prot = prot;
get_task_struct(current);
dma->task = current;
/* Insert zero-sized and grow as we map chunks of it */ /* Insert zero-sized and grow as we map chunks of it */
vfio_link_dma(iommu, dma); vfio_link_dma(iommu, dma);
while (size) { ret = vfio_pin_map_dma(iommu, dma, size);
/* Pin a contiguous chunk of memory */ out_unlock:
npage = vfio_pin_pages_remote(vaddr + dma->size,
size >> PAGE_SHIFT, prot, &pfn);
if (npage <= 0) {
WARN_ON(!npage);
ret = (int)npage;
break;
}
/* Map it! */
ret = vfio_iommu_map(iommu, iova + dma->size, pfn, npage, prot);
if (ret) {
vfio_unpin_pages_remote(pfn, npage, prot, true);
break;
}
size -= npage << PAGE_SHIFT;
dma->size += npage << PAGE_SHIFT;
}
if (ret)
vfio_remove_dma(iommu, dma);
mutex_unlock(&iommu->lock); mutex_unlock(&iommu->lock);
return ret; return ret;
} }
......
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