On 10/23/2017 04:20 AM, Borislav Petkov wrote:
On Thu, Oct 19, 2017 at 09:33:48PM -0500, Brijesh Singh wrote:+static int __sev_platform_init(struct sev_data_init *data, int *error) +{ + int rc = 0; + + mutex_lock(&fw_init_mutex); + + if (!fw_init_count) {I still don't like global semaphores. Can you get the status and check for PSTATE.INIT state and do the init only if the platform is in PSTATE.UNINIT?
Calling PLATFORM_GET_STATUS is not required, we can manage the state through a simple ref count variable. Issuing PSP commands will always be much more expensive compare to accessing a protected global variable. I would prefer to avoid invoking PSP command if possible. Additionally, the global semaphore is still needed to serialize the sev_platform_init() and sev_platform_shutdown() from multiple processes. e.g If process "A" calls sev_platform_init() and if it gets preempted due to whatever reason then we don't want another process to issue the shutdown command while process "A" is in middle of sev_platform_init().
-Brijesh
