[PATCH] drm/amdgpu: replace iova debugfs file with iomem (v3)

[Tom St Denis]

This allows access to pages allocated through the driver with optional
IOMMU mapping.

v2: Fix number of bytes copied and add write method
v3: drop check for kmap return

Original-by: Christian König 
Signed-off-by: Tom St Denis 
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 102 +---
 1 file changed, 81 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index b372d8d650a5..1338c908056f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -1929,38 +1929,98 @@ static const struct file_operations amdgpu_ttm_gtt_fops 
= {
 
 #endif
 
-static ssize_t amdgpu_iova_to_phys_read(struct file *f, char __user *buf,
-  size_t size, loff_t *pos)
+static ssize_t amdgpu_iomem_read(struct file *f, char __user *buf,
+size_t size, loff_t *pos)
 {
struct amdgpu_device *adev = file_inode(f)->i_private;
-   int r;
-   uint64_t phys;
struct iommu_domain *dom;
+   ssize_t result = 0;
+   int r;
 
-   // always return 8 bytes
-   if (size != 8)
-   return -EINVAL;
+   dom = iommu_get_domain_for_dev(adev->dev);
 
-   // only accept page addresses
-   if (*pos & 0xFFF)
-   return -EINVAL;
+   while (size) {
+   phys_addr_t addr = *pos & PAGE_MASK;
+   loff_t off = *pos & ~PAGE_MASK;
+   size_t bytes = PAGE_SIZE - off;
+   unsigned long pfn;
+   struct page *p;
+   void *ptr;
+
+   bytes = bytes < size ? bytes : size;
+
+   addr = dom ? iommu_iova_to_phys(dom, addr) : addr;
+
+   pfn = addr >> PAGE_SHIFT;
+   if (!pfn_valid(pfn))
+   return -EPERM;
+
+   p = pfn_to_page(pfn);
+   if (p->mapping != adev->mman.bdev.dev_mapping)
+   return -EPERM;
+
+   ptr = kmap(p);
+   r = copy_to_user(buf, ptr, bytes);
+   kunmap(p);
+   if (r)
+   return -EFAULT;
+
+   size -= bytes;
+   *pos += bytes;
+   result += bytes;
+   }
+
+   return result;
+}
+
+static ssize_t amdgpu_iomem_write(struct file *f, const char __user *buf,
+size_t size, loff_t *pos)
+{
+   struct amdgpu_device *adev = file_inode(f)->i_private;
+   struct iommu_domain *dom;
+   ssize_t result = 0;
+   int r;
 
dom = iommu_get_domain_for_dev(adev->dev);
-   if (dom)
-   phys = iommu_iova_to_phys(dom, *pos);
-   else
-   phys = *pos;
 
-   r = copy_to_user(buf, , 8);
-   if (r)
-   return -EFAULT;
+   while (size) {
+   phys_addr_t addr = *pos & PAGE_MASK;
+   loff_t off = *pos & ~PAGE_MASK;
+   size_t bytes = PAGE_SIZE - off;
+   unsigned long pfn;
+   struct page *p;
+   void *ptr;
+
+   bytes = bytes < size ? bytes : size;
 
-   return 8;
+   addr = dom ? iommu_iova_to_phys(dom, addr) : addr;
+
+   pfn = addr >> PAGE_SHIFT;
+   if (!pfn_valid(pfn))
+   return -EPERM;
+
+   p = pfn_to_page(pfn);
+   if (p->mapping != adev->mman.bdev.dev_mapping)
+   return -EPERM;
+
+   ptr = kmap(p);
+   r = copy_from_user(ptr, buf, bytes);
+   kunmap(p);
+   if (r)
+   return -EFAULT;
+
+   size -= bytes;
+   *pos += bytes;
+   result += bytes;
+   }
+
+   return result;
 }
 
-static const struct file_operations amdgpu_ttm_iova_fops = {
+static const struct file_operations amdgpu_ttm_iomem_fops = {
.owner = THIS_MODULE,
-   .read = amdgpu_iova_to_phys_read,
+   .read = amdgpu_iomem_read,
+   .write = amdgpu_iomem_write,
.llseek = default_llseek
 };
 
@@ -1973,7 +2033,7 @@ static const struct {
 #ifdef CONFIG_DRM_AMDGPU_GART_DEBUGFS
{ "amdgpu_gtt", _ttm_gtt_fops, TTM_PL_TT },
 #endif
-   { "amdgpu_iova", _ttm_iova_fops, TTM_PL_SYSTEM },
+   { "amdgpu_iomem", _ttm_iomem_fops, TTM_PL_SYSTEM },
 };
 
 #endif
-- 
2.14.3

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[PATCH] drm/amdgpu: replace iova debugfs file with iomem (v3)

[Tom St Denis]

From: Christian König 

This allows access to pages allocated through the driver with optional
IOMMU mapping.

v2: Fix number of bytes copied and add write method
v3: drop check for kmap return

Original-by: Christian König 
Signed-off-by: Tom St Denis 
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 102 +---
 1 file changed, 81 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index b372d8d650a5..1338c908056f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -1929,38 +1929,98 @@ static const struct file_operations amdgpu_ttm_gtt_fops 
= {
 
 #endif
 
-static ssize_t amdgpu_iova_to_phys_read(struct file *f, char __user *buf,
-  size_t size, loff_t *pos)
+static ssize_t amdgpu_iomem_read(struct file *f, char __user *buf,
+size_t size, loff_t *pos)
 {
struct amdgpu_device *adev = file_inode(f)->i_private;
-   int r;
-   uint64_t phys;
struct iommu_domain *dom;
+   ssize_t result = 0;
+   int r;
 
-   // always return 8 bytes
-   if (size != 8)
-   return -EINVAL;
+   dom = iommu_get_domain_for_dev(adev->dev);
 
-   // only accept page addresses
-   if (*pos & 0xFFF)
-   return -EINVAL;
+   while (size) {
+   phys_addr_t addr = *pos & PAGE_MASK;
+   loff_t off = *pos & ~PAGE_MASK;
+   size_t bytes = PAGE_SIZE - off;
+   unsigned long pfn;
+   struct page *p;
+   void *ptr;
+
+   bytes = bytes < size ? bytes : size;
+
+   addr = dom ? iommu_iova_to_phys(dom, addr) : addr;
+
+   pfn = addr >> PAGE_SHIFT;
+   if (!pfn_valid(pfn))
+   return -EPERM;
+
+   p = pfn_to_page(pfn);
+   if (p->mapping != adev->mman.bdev.dev_mapping)
+   return -EPERM;
+
+   ptr = kmap(p);
+   r = copy_to_user(buf, ptr, bytes);
+   kunmap(p);
+   if (r)
+   return -EFAULT;
+
+   size -= bytes;
+   *pos += bytes;
+   result += bytes;
+   }
+
+   return result;
+}
+
+static ssize_t amdgpu_iomem_write(struct file *f, const char __user *buf,
+size_t size, loff_t *pos)
+{
+   struct amdgpu_device *adev = file_inode(f)->i_private;
+   struct iommu_domain *dom;
+   ssize_t result = 0;
+   int r;
 
dom = iommu_get_domain_for_dev(adev->dev);
-   if (dom)
-   phys = iommu_iova_to_phys(dom, *pos);
-   else
-   phys = *pos;
 
-   r = copy_to_user(buf, , 8);
-   if (r)
-   return -EFAULT;
+   while (size) {
+   phys_addr_t addr = *pos & PAGE_MASK;
+   loff_t off = *pos & ~PAGE_MASK;
+   size_t bytes = PAGE_SIZE - off;
+   unsigned long pfn;
+   struct page *p;
+   void *ptr;
+
+   bytes = bytes < size ? bytes : size;
 
-   return 8;
+   addr = dom ? iommu_iova_to_phys(dom, addr) : addr;
+
+   pfn = addr >> PAGE_SHIFT;
+   if (!pfn_valid(pfn))
+   return -EPERM;
+
+   p = pfn_to_page(pfn);
+   if (p->mapping != adev->mman.bdev.dev_mapping)
+   return -EPERM;
+
+   ptr = kmap(p);
+   r = copy_from_user(ptr, buf, bytes);
+   kunmap(p);
+   if (r)
+   return -EFAULT;
+
+   size -= bytes;
+   *pos += bytes;
+   result += bytes;
+   }
+
+   return result;
 }
 
-static const struct file_operations amdgpu_ttm_iova_fops = {
+static const struct file_operations amdgpu_ttm_iomem_fops = {
.owner = THIS_MODULE,
-   .read = amdgpu_iova_to_phys_read,
+   .read = amdgpu_iomem_read,
+   .write = amdgpu_iomem_write,
.llseek = default_llseek
 };
 
@@ -1973,7 +2033,7 @@ static const struct {
 #ifdef CONFIG_DRM_AMDGPU_GART_DEBUGFS
{ "amdgpu_gtt", _ttm_gtt_fops, TTM_PL_TT },
 #endif
-   { "amdgpu_iova", _ttm_iova_fops, TTM_PL_SYSTEM },
+   { "amdgpu_iomem", _ttm_iomem_fops, TTM_PL_SYSTEM },
 };
 
 #endif
-- 
2.14.3

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