On Mon, May 10, 2021 at 7:22 PM Andi Kleen <ak@xxxxxxxxxxxxxxx> wrote: > > On Mon, May 10, 2021 at 10:10:24AM -0700, Kuppuswamy, Sathyanarayanan wrote: > > > > > > On 5/10/21 9:55 AM, Rafael J. Wysocki wrote: > > > I'm not sure how my comment regarding the fact that for a given CPU > > > this function is only usable once has been addressed. > > > > > > While it may not be a practical concern in the use case that you are > > > after (TDX), this is a generic mechanism and it needs to cover other > > > possible usage scenarios. > > > > For the same CPU, if we try to use mailbox again, firmware will not > > respond to it. So the command will timeout and return error. > > Right because the firmware code doesn't run anymore. > > The only possibility would be for Linux to put back some code that spins > and waits again, but that would be quite pointless and wasteful. The wakeup function can return an error when it is called for the second time on the same CPU.
