On Wed, Mar 15, 2023, at 16:51, Manivannan Sadhasivam wrote:
> On Wed, Mar 08, 2023 at 06:03:06PM +0900, Damien Le Moal wrote:
>> + /*
>> + * Set the status before raising the IRQ to ensure that the host sees
>> + * the updated value when it gets the IRQ.
>> + */
>> + WRITE_ONCE(reg->status, status);
>
> For MMIO, it is not sufficient to use WRITE_ONCE() and expect that the write
> has reached the memory (it could be stored in a write buffer). If you really
> care about synchronization, then you should do a read back of the variable.
This is not MMIO, this is the local access to a variable that is accessed
through MMIO from the remote host. Reading it back would not change anything
here as far as I can tell,
Arnd
