diff options
Diffstat (limited to 'sys/dev/pv/pvclock.c')
| -rw-r--r-- | sys/dev/pv/pvclock.c | 27 |
1 files changed, 24 insertions, 3 deletions
diff --git a/sys/dev/pv/pvclock.c b/sys/dev/pv/pvclock.c index 123efab610d..05eebf783c2 100644 --- a/sys/dev/pv/pvclock.c +++ b/sys/dev/pv/pvclock.c @@ -1,4 +1,4 @@ -/* $OpenBSD: pvclock.c,v 1.2 2018/11/24 13:12:29 phessler Exp $ */ +/* $OpenBSD: pvclock.c,v 1.3 2018/12/05 18:02:51 reyk Exp $ */ /* * Copyright (c) 2018 Reyk Floeter <reyk@openbsd.org> @@ -70,6 +70,11 @@ uint pvclock_get_timecount(struct timecounter *); 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, void *match, void *aux) 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) { @@ -144,6 +152,19 @@ pvclock_attach(struct device *parent, struct device *self, void *aux) 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); sc->sc_tc->tc_frequency = 1000000000ULL; |