On 20/07/17 09:09, Felix Schmoll wrote:
Implement reading from PV console. Making use of polling.
Signed-off-by: Felix Schmoll <eggi.innovati...@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 */
/*
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