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drm/amd/amdgpu: Partial revert of iova debugfs

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We discovered that on some devices even with iommu enabled
you can access all of system memory through the iommu translation.

Therefore, we revert the read method to the translation only service
and drop the write method completely.

Signed-off-by: Tom St Denis <tom.stdenis@amd.com>
Reviewed-by: Christan König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Tom St Denis 2017-09-19 11:29:04 -04:00 committed by Alex Deucher
parent a49ccdbd1d
commit 10cfafd62a
1 changed files with 14 additions and 78 deletions
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92
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
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@ -1784,98 +1784,34 @@ static ssize_t amdgpu_iova_to_phys_read(struct file *f, char __user *buf,
size_t size, loff_t *pos)
{
struct amdgpu_device *adev = file_inode(f)->i_private;
ssize_t result, n;
int r;
uint64_t phys;
void *ptr;
struct iommu_domain *dom;
dom = iommu_get_domain_for_dev(adev->dev);
if (!dom)
return -EFAULT;
// always return 8 bytes
if (size != 8)
return -EINVAL;
result = 0;
while (size) {
// get physical address and map
phys = iommu_iova_to_phys(dom, *pos);
// copy upto one page
if (size > PAGE_SIZE)
n = PAGE_SIZE;
else
n = size;
// to end of the page
if (((*pos & (PAGE_SIZE - 1)) + n) >= PAGE_SIZE)
n = PAGE_SIZE - (*pos & (PAGE_SIZE - 1));
ptr = kmap(pfn_to_page(PFN_DOWN(phys)));
if (!ptr)
return -EFAULT;
r = copy_to_user(buf, ptr, n);
kunmap(pfn_to_page(PFN_DOWN(phys)));
if (r)
return -EFAULT;
*pos += n;
size -= n;
result += n;
}
return result;
}
static ssize_t amdgpu_iova_to_phys_write(struct file *f, const char __user *buf,
size_t size, loff_t *pos)
{
struct amdgpu_device *adev = file_inode(f)->i_private;
ssize_t result, n;
int r;
uint64_t phys;
void *ptr;
struct iommu_domain *dom;
// only accept page addresses
if (*pos & 0xFFF)
return -EINVAL;
dom = iommu_get_domain_for_dev(adev->dev);
if (!dom)
if (dom)
phys = iommu_iova_to_phys(dom, *pos);
else
phys = *pos;
r = copy_to_user(buf, &phys, 8);
if (r)
return -EFAULT;
result = 0;
while (size) {
// get physical address and map
phys = iommu_iova_to_phys(dom, *pos);
// copy upto one page
if (size > PAGE_SIZE)
n = PAGE_SIZE;
else
n = size;
// to end of the page
if (((*pos & (PAGE_SIZE - 1)) + n) >= PAGE_SIZE)
n = PAGE_SIZE - (*pos & (PAGE_SIZE - 1));
ptr = kmap(pfn_to_page(PFN_DOWN(phys)));
if (!ptr)
return -EFAULT;
r = copy_from_user(ptr, buf, n);
kunmap(pfn_to_page(PFN_DOWN(phys)));
if (r)
return -EFAULT;
*pos += n;
size -= n;
result += n;
}
return result;
return 8;
}
static const struct file_operations amdgpu_ttm_iova_fops = {
.owner = THIS_MODULE,
.read = amdgpu_iova_to_phys_read,
.write = amdgpu_iova_to_phys_write,
.llseek = default_llseek
};