On Wed, Dec 14, 2011 at 08:43:17AM -0500, Stefan Berger wrote:
> +/*
> + * Send a TPM request.
> + * Call this with the state_lock held so we can sync with the receive
> + * callback.
> + */
> +static void tpm_tis_tpm_send(TPMState *s, uint8_t locty)
> +{
> + TPMTISState *tis = &s->s.tis;
> +
> + tpm_tis_show_buffer(&tis->loc[locty].w_buffer, "tpm_tis: To TPM");
> +
> + s->command_locty = locty;
> + s->cmd_locty = &tis->loc[locty];
> +
> + /* w_offset serves as length indicator for length of data;
> + it's reset when the response comes back */
> + tis->loc[locty].status = TPM_TIS_STATUS_EXECUTION;
> + tis->loc[locty].sts &= ~TPM_TIS_STS_EXPECT;
> +
> + s->to_tpm_execute = true;
> + qemu_cond_signal(&s->to_tpm_cond);
> +}
What happens IIUC is that frondend sets to_tpm_execute
and signals a condition, and backend clears it
and waits on a condition.
So how about moving all the signalling
and locking out to backend, and have frontend
invoke a callback to signal it?
The whole threading thing then becomes a work-around
for a backend that does not support select,
instead of spilling out into frontend?
--
MST
