On 05/25/2018 11:40 AM, Cornelia Huck wrote:
On Thu, 24 May 2018 19:58:27 +0200
Halil Pasic <pa...@linux.ibm.com> wrote:
There is at least one guest (OS) such that although it does not rely on
the guarantees provided by ORB 1 word 9 bit (aka unlimited prefetch, aka
P bit) not being set, it fails to tell this to the machine.
[..]
+static inline void warn_once(bool *warned, const char *fmt, ...)
+{
+ va_list ap;
+
+ if (!warned || *warned) {
+ return;
+ }
+ *warned = true;
+ va_start(ap, fmt);
+ warn_vreport(fmt, ap);
+ va_end(ap);
+}
+
+static inline void warn_once_pfch(VFIOCCWDevice *vcdev, SubchDev *sch,
+ const char *msg)
+{
+ warn_once(&vcdev->warned_orb_pfch, "vfio-ccw (devno %x.%x.%04x): %s",
+ sch->cssid, sch->ssid, sch->devno, msg);
+}
+
While I still think we want warn_once() in common error handling code,
this looks reasonable enough. We can still move it later.
I agree. I was a bit surprised to not find any warn_once functionality.
Let see what Markus says.
static void vfio_ccw_compute_needs_reset(VFIODevice *vdev)
{
vdev->needs_reset = false;
@@ -54,6 +76,18 @@ static IOInstEnding vfio_ccw_handle_request(SubchDev *sch)
struct ccw_io_region *region = vcdev->io_region;
int ret;
+ if (!(sch->orb.ctrl0 & ORB_CTRL0_MASK_PFCH)) {
+ if (!(vcdev->force_orb_pfch)) {
+ warn_once_pfch(vcdev, sch, "requires PFCH flag set");
+ sch_gen_unit_exception(sch);
+ css_inject_io_interrupt(sch);
+ return IOINST_CC_EXPECTED;
+ } else {
+ sch->orb.ctrl0 |= ORB_CTRL0_MASK_PFCH;
+ warn_once_pfch(vcdev, sch, "PFCH flag forced");
+ }
+ }
+
Looks good to me. I plan to queue this (and the other patch) to
s390-next, but (as always) further tags are still welcome :)
Thanks!
Halil
