On Mon, 18 Oct 2021 16:26:16 +0300
Yishai Hadas [off-list ref] wrote:

On 10/18/2021 2:51 PM, Jason Gunthorpe wrote:

quoted

On Sun, Oct 17, 2021 at 05:03:28PM +0300, Yishai Hadas wrote:  

quoted

On 10/15/2021 11:59 PM, Alex Williamson wrote:  

quoted

On Fri, 15 Oct 2021 17:16:54 -0300
Jason Gunthorpe [off-list ref] wrote:
 

quoted

On Fri, Oct 15, 2021 at 02:12:01PM -0600, Alex Williamson wrote:  

quoted

On Fri, 15 Oct 2021 16:59:37 -0300
Jason Gunthorpe [off-list ref] wrote:  

quoted

On Fri, Oct 15, 2021 at 01:48:20PM -0600, Alex Williamson wrote:  

quoted

quoted

+static int mlx5vf_pci_set_device_state(struct mlx5vf_pci_core_device *mvdev,
+				       u32 state)
+{
+	struct mlx5vf_pci_migration_info *vmig = &mvdev->vmig;
+	u32 old_state = vmig->vfio_dev_state;
+	int ret = 0;
+
+	if (vfio_is_state_invalid(state) || vfio_is_state_invalid(old_state))
+		return -EINVAL;  

if (!VFIO_DEVICE_STATE_VALID(old_state) || !VFIO_DEVICE_STATE_VALID(state))  

AFAICT this macro doesn't do what is needed, eg

VFIO_DEVICE_STATE_VALID(0xF000) == true

What Yishai implemented is at least functionally correct - states this
driver does not support are rejected.  

if (!VFIO_DEVICE_STATE_VALID(old_state) || !VFIO_DEVICE_STATE_VALID(state)) || (state & ~VFIO_DEVICE_STATE_MASK))

old_state is controlled by the driver and can never have random bits
set, user state should be sanitized to prevent setting undefined bits.  

In that instance let's just write

old_state != VFIO_DEVICE_STATE_ERROR

?  

Not quite, the user can't set either of the other invalid states
either.  

OK so let's go with below as you suggested.
if (!VFIO_DEVICE_STATE_VALID(old_state) ||
      !VFIO_DEVICE_STATE_VALID(state) ||
       (state & ~VFIO_DEVICE_STATE_MASK))
              

This is my preference:

if (vmig->vfio_dev_state != VFIO_DEVICE_STATE_ERROR ||
     !vfio_device_state_valid(state) ||
     (state & !MLX5VF_SUPPORTED_DEVICE_STATES))
 

OK, let's go with this approach which enforces what the driver supports 
as well.

We may have the below post making it accurate and complete.

enum {
     MLX5VF_SUPPORTED_DEVICE_STATES = VFIO_DEVICE_STATE_RUNNING |
                                      VFIO_DEVICE_STATE_SAVING |
                                      VFIO_DEVICE_STATE_RESUMING,
};

if (old_state == VFIO_DEVICE_STATE_ERROR ||
     !vfio_device_state_valid(state) ||
     (state & ~MLX5VF_SUPPORTED_DEVICE_STATES))
           return -EINVAL;

quoted

quoted

diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index b53a9557884a..37376dadca5a 100644
+++ b/include/linux/vfio.h

@@ -15,6 +15,8 @@
  #include <linux/poll.h>
  #include <uapi/linux/vfio.h>

+static const int VFIO_DEVICE_STATE_ERROR = VFIO_DEVICE_STATE_SAVING |
+ VFIO_DEVICE_STATE_RESUMING;  

Do not put static variables in header files

Jason  

OK, we can come with an enum instead.

enum {

VFIO_DEVICE_STATE_ERROR = VFIO_DEVICE_STATE_SAVING | VFIO_DEVICE_STATE_RESUMING,

};

Alex,

Do you prefer to  put it under include/uapi/vfio.h or that it can go 
under inlcude/linux/vfio.h for internal drivers usage ?

I don't understand why this wouldn't just be a continuation of the
#defines in the uapi header.  Thanks,

Alex