From: Jason Gunthorpe jgg@nvidia.com Sent: Friday, August 4, 2023 10:12 PM
On Fri, Aug 04, 2023 at 09:59:11AM +0800, Baolu Lu wrote:
On 2023/8/3 22:31, Yi Liu wrote:
Under nested IOMMU translation, userspace owns the stage-1 translation table (e.g. the stage-1 page table of Intel VT-d or the context table of ARM SMMUv3, and etc.). Stage-1 translation tables are vendor specific, and need to be compatiable with the underlying IOMMU hardware. Hence,
compatibleuserspace should know the IOMMU hardware capability before creating and configuring the stage-1 translation table to kernel.
This adds IOMMU_GET_HW_INFO ioctl to query the IOMMU hardware information (a.k.a capability) for a given device. The returned data is vendor specific, userspace needs to decode it with the structure mapped by the @out_data_type field.
As only physical devices have IOMMU hardware, so this will return error if the given device is not a physical device.
Co-developed-by: Nicolin Chen nicolinc@nvidia.com Signed-off-by: Nicolin Chen nicolinc@nvidia.com Signed-off-by: Yi Liu yi.l.liu@intel.com
drivers/iommu/iommufd/main.c | 79 ++++++++++++++++++++++++++++++++++++ include/uapi/linux/iommufd.h | 36 ++++++++++++++++ 2 files changed, 115 insertions(+)
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c index 94c498b8fdf6..a0302bcaa97c 100644 --- a/drivers/iommu/iommufd/main.c +++ b/drivers/iommu/iommufd/main.c @@ -17,6 +17,7 @@ #include <linux/bug.h> #include <uapi/linux/iommufd.h> #include <linux/iommufd.h> +#include "../iommu-priv.h" #include "io_pagetable.h" #include "iommufd_private.h" @@ -177,6 +178,81 @@ static int iommufd_destroy(struct iommufd_ucmd *ucmd) return 0; } +static int iommufd_zero_fill_user(void __user *ptr, size_t bytes) +{
- int index = 0;
- for (; index < bytes; index++) {
if (put_user(0, (uint8_t __user *)(ptr + index)))return -EFAULT;- }
- return 0;
+}
+static int iommufd_get_hw_info(struct iommufd_ucmd *ucmd) +{
- u32 hw_info_type = IOMMU_HW_INFO_TYPE_NONE;
- struct iommu_hw_info *cmd = ucmd->cmd;
- unsigned int length = 0, data_len;
- struct iommufd_device *idev;
- const struct iommu_ops *ops;
- void __user *user_ptr;
- void *data = NULL;
- int rc = 0;
- if (cmd->flags || cmd->__reserved || !cmd->data_len)
return -EOPNOTSUPP;- idev = iommufd_get_device(ucmd, cmd->dev_id);
- if (IS_ERR(idev))
return PTR_ERR(idev);- user_ptr = u64_to_user_ptr(cmd->data_ptr);
- ops = dev_iommu_ops(idev->dev);
- if (!ops->hw_info)
goto done;- data = ops->hw_info(idev->dev, &data_len, &hw_info_type);
- if (IS_ERR(data)) {
rc = PTR_ERR(data);goto out_err;Can kfree() handle a ERR_PTR input? I am afraid not,
/**
- kfree - free previously allocated memory
- @object: pointer returned by kmalloc() or kmem_cache_alloc()
- If @object is NULL, no operation is performed.
*/ void kfree(const void *object) { struct folio *folio; struct slab *slab; struct kmem_cache *s;
trace_kfree(_RET_IP_, object); if (unlikely(ZERO_OR_NULL_PTR(object))) return;So, perhaps we should add
data = NULL;
before goto out_err;
No, use more labels.
- }
- /* driver has hw_info callback should have a unique hw_info_type */
- if (WARN_ON_ONCE(hw_info_type == IOMMU_HW_INFO_TYPE_NONE)) {
rc = -ENODEV;goto out_err;- }
- length = min(cmd->data_len, data_len);
- if (copy_to_user(user_ptr, data, length)) {
rc = -EFAULT;goto out_err;- }
+done:
No label here, put it in a if {}
How about below?
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c index 94c498b8fdf6..a8bb7da87036 100644 --- a/drivers/iommu/iommufd/main.c +++ b/drivers/iommu/iommufd/main.c @@ -17,6 +17,7 @@ #include <linux/bug.h> #include <uapi/linux/iommufd.h> #include <linux/iommufd.h> +#include "../iommu-priv.h"
#include "io_pagetable.h" #include "iommufd_private.h" @@ -177,6 +178,80 @@ static int iommufd_destroy(struct iommufd_ucmd *ucmd) return 0; }
+static int iommufd_zero_fill_user(void __user *ptr, size_t bytes) +{ + int index = 0; + + for (; index < bytes; index++) { + if (put_user(0, (uint8_t __user *)(ptr + index))) + return -EFAULT; + } + return 0; +} + +static int iommufd_get_hw_info(struct iommufd_ucmd *ucmd) +{ + u32 hw_info_type = IOMMU_HW_INFO_TYPE_NONE; + struct iommu_hw_info *cmd = ucmd->cmd; + unsigned int length = 0, data_len; + struct iommufd_device *idev; + const struct iommu_ops *ops; + void __user *user_ptr; + void *data = NULL; + int rc = 0; + + if (cmd->flags || cmd->__reserved || !cmd->data_len) + return -EOPNOTSUPP; + + idev = iommufd_get_device(ucmd, cmd->dev_id); + if (IS_ERR(idev)) + return PTR_ERR(idev); + + user_ptr = u64_to_user_ptr(cmd->data_ptr); + + ops = dev_iommu_ops(idev->dev); + if (ops->hw_info) { + data = ops->hw_info(idev->dev, &data_len, &hw_info_type); + if (IS_ERR(data)) { + rc = PTR_ERR(data); + goto err_put; + } + + /* driver has hw_info callback should have a unique hw_info_type */ + if (WARN_ON_ONCE(hw_info_type == IOMMU_HW_INFO_TYPE_NONE)) { + rc = -ENODEV; + goto err_free; + } + + length = min(cmd->data_len, data_len); + if (copy_to_user(user_ptr, data, length)) { + rc = -EFAULT; + goto err_free; + } + } + + /* + * Zero the trailing bytes if the user buffer is bigger than the + * data size kernel actually has. + */ + if (length < cmd->data_len) { + rc = iommufd_zero_fill_user(user_ptr + length, + cmd->data_len - length); + if (rc) + goto err_free; + } + + cmd->data_len = length; + cmd->out_data_type = hw_info_type; + rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd)); + +err_free: + kfree(data); +err_put: + iommufd_put_object(&idev->obj); + return rc; +} + static int iommufd_fops_open(struct inode *inode, struct file *filp) { struct iommufd_ctx *ictx;
Regards, Yi Liu
- /*
* Zero the trailing bytes if the user buffer is bigger than the* data size kernel actually has.*/- if (length < cmd->data_len) {
rc = iommufd_zero_fill_user(user_ptr + length,cmd->data_len - length);if (rc)goto out_err;- }
- cmd->data_len = length;
- cmd->out_data_type = hw_info_type;
- rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd));
+out_err:
err_free:
- kfree(data);
err_put:
- iommufd_put_object(&idev->obj);
- return rc;
+}
Jason