Hi Ilpo,
On 11/21/2023 5:47 PM, Ilpo Järvinen wrote:
> On Fri, 17 Nov 2023, Shyam Sundar S K wrote:
>
>> A policy binary is OS agnostic, and the same policies are expected to work
>> across the OSes. At times it becomes difficult to debug when the policies
>> inside the policy binaries starts to misbehave. Add a way to sideload such
>> policies independently to debug them via a debugfs entry.
>>
>> Reviewed-by: Mario Limonciello <mario.limonciello@xxxxxxx>
>> Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@xxxxxxx>
>> ---
>
>> diff --git a/drivers/platform/x86/amd/pmf/tee-if.c b/drivers/platform/x86/amd/pmf/tee-if.c
>> index 5f10e5c6335e..f73663c629fe 100644
>> --- a/drivers/platform/x86/amd/pmf/tee-if.c
>> +++ b/drivers/platform/x86/amd/pmf/tee-if.c
>
>> +#ifdef CONFIG_AMD_PMF_DEBUG
>> +static ssize_t amd_pmf_get_pb_data(struct file *filp, const char __user *buf,
>> + size_t length, loff_t *pos)
>> +{
>> + struct amd_pmf_dev *dev = filp->private_data;
>> + int ret;
>> +
>> + /* Policy binary size cannot exceed POLICY_BUF_MAX_SZ */
>> + if (length > POLICY_BUF_MAX_SZ || length == 0)
>> + return -EINVAL;
>> +
>> + dev->policy_sz = length;
>> + if (copy_from_user(dev->policy_buf, buf, dev->policy_sz))
>> + return -EFAULT;
>> +
>> + ret = amd_pmf_start_policy_engine(dev);
>
> Is this call safe against concurrent invocations from two racing writes?
>
> Other than that, this change looked fine.
This path gets enabled only when CONFIG_AMD_PMF_DEBUG option is
enabled. Also when enabled, did not observe anything really unusual
(like races). So I have retained the same code in v6.
Kindly take a look.
Thanks,
Shyam
>
>> + if (ret)
>> + return -EINVAL;
>> +
>> + return length;
>> +}
>
>
