On Tue, Dec 04, 2018 at 05:43:48AM -0800, Chris Cappuccio wrote:
> Of course printf instead of panic for testers
>
Oh, right, thanks!
@john: Does this "slightly less simple" diff work for you?
@phessler, Chris: Maybe we should get this fix tested and in, wait for
reports, and I can use the time to think about my other option. What
do you think?
Reyk
Index: sys/dev/pv/pvclock.c
===================================================================
RCS file: /cvs/src/sys/dev/pv/pvclock.c,v
retrieving revision 1.2
diff -u -p -u -p -r1.2 pvclock.c
--- sys/dev/pv/pvclock.c 24 Nov 2018 13:12:29 -0000 1.2
+++ sys/dev/pv/pvclock.c 4 Dec 2018 14:03:57 -0000
@@ -70,6 +70,11 @@ uint pvclock_get_timecount(struct timec
void pvclock_read_time_info(struct pvclock_softc *,
struct pvclock_time_info *);
+static inline uint32_t
+ pvclock_read_begin(const struct pvclock_time_info *);
+static inline int
+ pvclock_read_done(const struct pvclock_time_info *, uint32_t);
+
struct cfattach pvclock_ca = {
sizeof(struct pvclock_softc),
pvclock_match,
@@ -127,8 +132,11 @@ pvclock_match(struct device *parent, voi
void
pvclock_attach(struct device *parent, struct device *self, void *aux)
{
- struct pvclock_softc *sc = (struct pvclock_softc *)self;
- paddr_t pa;
+ struct pvclock_softc *sc = (struct pvclock_softc *)self;
+ struct pvclock_time_info *ti;
+ paddr_t pa;
+ uint32_t version;
+ uint8_t flags;
if ((sc->sc_time = km_alloc(PAGE_SIZE,
&kv_any, &kp_zero, &kd_nowait)) == NULL) {
@@ -143,6 +151,19 @@ pvclock_attach(struct device *parent, st
wrmsr(KVM_MSR_SYSTEM_TIME, pa | PVCLOCK_SYSTEM_TIME_ENABLE);
sc->sc_paddr = pa;
+
+ ti = sc->sc_time;
+ do {
+ version = pvclock_read_begin(ti);
+ flags = ti->ti_flags;
+ } while (!pvclock_read_done(ti, version));
+
+ if ((flags & PVCLOCK_FLAG_TSC_STABLE) == 0) {
+ wrmsr(KVM_MSR_SYSTEM_TIME, pa & ~PVCLOCK_SYSTEM_TIME_ENABLE);
+ km_free(sc->sc_time, PAGE_SIZE, &kv_any, &kp_zero);
+ printf(": unstable clock\n");
+ return;
+ }
sc->sc_tc = &pvclock_timecounter;
sc->sc_tc->tc_name = DEVNAME(sc);
