| Message ID | 20170720080942.4137-1-eggi.innovations@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 20/07/17 09:09, Felix Schmoll wrote: > Implement reading from PV console. Making use of polling. > > Signed-off-by: Felix Schmoll <eggi.innovations@gmail.com> > > --- > Changed since v2: > * Change function name from pv_read to pv_read_some > * Add comment to function name > * Remove unnecessary code > --- > common/console.c | 24 ++++++++++++++++++++++++ > include/xtf/console.h | 2 ++ > 2 files changed, 26 insertions(+) > > diff --git a/common/console.c b/common/console.c > index 7cb2361..1b79652 100644 > --- a/common/console.c > +++ b/common/console.c > @@ -46,6 +46,30 @@ static size_t pv_console_write_some(const char *buf, size_t len) > } > > /* > + * Read out data from the pv ring, either until buffer is filled or no > + * more data are available. Might result in partial strings, depending > + * on how xenconsoled passes in data. Much better. Just one final question. Do you intend this function to block until data becomes available? (because that appears to be how it behaves.) ~Andrew > + */ > +size_t pv_console_read_some(char *buf, size_t len) > +{ > + size_t s = 0; > + uint32_t cons, prod; > + > + while ( !test_and_clear_bit(pv_evtchn, shared_info.evtchn_pending) || > + (pv_ring->in_cons == pv_ring->in_prod) ) > + hypercall_poll(pv_evtchn); > + > + cons = pv_ring->in_cons, prod = LOAD_ACQUIRE(&pv_ring->in_prod); > + > + while ( (s < len) && (0 < (prod - cons)) ) > + buf[s++] = pv_ring->in[cons++ & (sizeof(pv_ring->in) - 1)]; > + > + STORE_RELEASE(&pv_ring->in_cons, cons); > + > + return s; > +} > + > +/* > * Write some data into the pv ring, synchronously waiting for all data to be > * consumed. > */ > diff --git a/include/xtf/console.h b/include/xtf/console.h > index 2a93c06..caec790 100644 > --- a/include/xtf/console.h > +++ b/include/xtf/console.h > @@ -25,6 +25,8 @@ void init_pv_console(xencons_interface_t *ring, > void vprintk(const char *fmt, va_list args) __printf(1, 0); > void printk(const char *fmt, ...) __printf(1, 2); > > +size_t pv_console_read_some(char *buf, size_t len); > + > #endif /* XTF_CONSOLE_H */ > > /*
> > > Much better. Just one final question. Do you intend this function to > block until data becomes available? (because that appears to be how it > behaves.) > > Yes. I could split it up into two functions if that bothers you. Or do you just want me to include that in the comment?
On 21/07/17 08:01, Felix Schmoll wrote: > > > Much better. Just one final question. Do you intend this > function to block until data becomes available? (because that > appears to be how it behaves.) > > > Yes. I could split it up into two functions if that bothers you. Or do > you just want me to include that in the comment? Just include it in the comment. ~Andrew
diff --git a/common/console.c b/common/console.c index 7cb2361..1b79652 100644 --- a/common/console.c +++ b/common/console.c @@ -46,6 +46,30 @@ static size_t pv_console_write_some(const char *buf, size_t len) } /* + * Read out data from the pv ring, either until buffer is filled or no + * more data are available. Might result in partial strings, depending + * on how xenconsoled passes in data. + */ +size_t pv_console_read_some(char *buf, size_t len) +{ + size_t s = 0; + uint32_t cons, prod; + + while ( !test_and_clear_bit(pv_evtchn, shared_info.evtchn_pending) || + (pv_ring->in_cons == pv_ring->in_prod) ) + hypercall_poll(pv_evtchn); + + cons = pv_ring->in_cons, prod = LOAD_ACQUIRE(&pv_ring->in_prod); + + while ( (s < len) && (0 < (prod - cons)) ) + buf[s++] = pv_ring->in[cons++ & (sizeof(pv_ring->in) - 1)]; + + STORE_RELEASE(&pv_ring->in_cons, cons); + + return s; +} + +/* * Write some data into the pv ring, synchronously waiting for all data to be * consumed. */ diff --git a/include/xtf/console.h b/include/xtf/console.h index 2a93c06..caec790 100644 --- a/include/xtf/console.h +++ b/include/xtf/console.h @@ -25,6 +25,8 @@ void init_pv_console(xencons_interface_t *ring, void vprintk(const char *fmt, va_list args) __printf(1, 0); void printk(const char *fmt, ...) __printf(1, 2); +size_t pv_console_read_some(char *buf, size_t len); + #endif /* XTF_CONSOLE_H */ /*
Implement reading from PV console. Making use of polling. Signed-off-by: Felix Schmoll <eggi.innovations@gmail.com> --- Changed since v2: * Change function name from pv_read to pv_read_some * Add comment to function name * Remove unnecessary code --- common/console.c | 24 ++++++++++++++++++++++++ include/xtf/console.h | 2 ++ 2 files changed, 26 insertions(+)