2017-07-18 17:04 GMT+02:00 Andrew Cooper <andrew.coop...@citrix.com>:
> On 18/07/17 15:53, Felix Schmoll wrote:
> > Implement reading from PV console. Making use of polling.
> >
> > Signed-off-by: Felix Schmoll <eggi.innovati...@gmail.com>
> > ---
> > common/console.c | 22 ++++++++++++++++++++++
> > include/xtf/console.h | 2 ++
> > 2 files changed, 24 insertions(+)
> >
> > diff --git a/common/console.c b/common/console.c
> > index 7cb2361..5895ccc 100644
> > --- a/common/console.c
> > +++ b/common/console.c
> > @@ -7,6 +7,8 @@
> > #include <xtf/libc.h>
> > #include <xtf/traps.h>
> >
> > +#include <xen/sched.h>
>
> Why is this needed?
>
>
Apparently it's not; will be removed in the next version of this patch.
> +
> > /*
> > * Output functions, registered if/when available.
> > * Possibilities:
> > @@ -45,6 +47,26 @@ static size_t pv_console_write_some(const char *buf,
> size_t len)
> > return s;
> > }
> >
> > +extern shared_info_t shared_info;
>
> This extern isn't needed.
>
> > +size_t pv_console_read(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..9b3f85d 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(char *buf, size_t len);
>
> What behaviour do you intend this function to have wrt partial strings?
>
>
I'd prefer the function to be as simple as possible. If a specific output
is expected that should be handled by the caller. The function name could
be adjusted to pv_console_read_some to reflect that better, in symmetry to
pv_console_write_some. That one isn't public though, which is why I didn't
do it initially.
Alternatively one could adopt a more well-known function such as readline,
as was done with printk in regard to printf.
> ~Andrew
>
> > +
> > #endif /* XTF_CONSOLE_H */
> >
> > /*
>
>
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