diff options
Diffstat (limited to 'xen.bug1026236.suse_vtsc_tolerance.patch')
| -rw-r--r-- | xen.bug1026236.suse_vtsc_tolerance.patch | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/xen.bug1026236.suse_vtsc_tolerance.patch b/xen.bug1026236.suse_vtsc_tolerance.patch new file mode 100644 index 0000000..17c8b68 --- /dev/null +++ b/xen.bug1026236.suse_vtsc_tolerance.patch @@ -0,0 +1,58 @@ +suse_vtsc_tolerance=<val> +Reference: bsc#1026236 + +To avoid emulation of vTSC after live migration or save/restore allow +different clock frequency up to the specified value. If the frequency +is within the allowed range TSC access by the domU will be performed +at native speed. Otherwise TSC access will be emulated. It is up to +the hostadmin to decide how much tolerance all running domUs can +actually handle. The default is zero tolerance. + +--- a/xen/arch/x86/time.c ++++ b/xen/arch/x86/time.c +@@ -43,6 +43,9 @@ + static char __initdata opt_clocksource[10]; + string_param("clocksource", opt_clocksource); + ++static unsigned int __read_mostly opt_suse_vtsc_tolerance; ++integer_param("suse_vtsc_tolerance", opt_suse_vtsc_tolerance); ++ + unsigned long __read_mostly cpu_khz; /* CPU clock frequency in kHz. */ + DEFINE_SPINLOCK(rtc_lock); + unsigned long pit0_ticks; +@@ -2226,6 +2229,7 @@ int tsc_set_info(struct domain *d, + + switch ( tsc_mode ) + { ++ bool disable_vtsc; + case TSC_MODE_DEFAULT: + case TSC_MODE_ALWAYS_EMULATE: + d->arch.vtsc_offset = get_s_time() - elapsed_nsec; +@@ -2239,8 +2243,26 @@ int tsc_set_info(struct domain *d, + * When a guest is created, gtsc_khz is passed in as zero, making + * d->arch.tsc_khz == cpu_khz. Thus no need to check incarnation. + */ ++ disable_vtsc = d->arch.tsc_khz == cpu_khz; ++ ++ if ( tsc_mode == TSC_MODE_DEFAULT && gtsc_khz && ++ is_hvm_domain(d) && opt_suse_vtsc_tolerance ) ++ { ++ long khz_diff; ++ ++ khz_diff = ABS(((long)cpu_khz - gtsc_khz)); ++ disable_vtsc = khz_diff <= opt_suse_vtsc_tolerance; ++ ++ printk(XENLOG_G_INFO "d%d: host has %lu kHz," ++ " domU expects %u kHz," ++ " difference of %ld is %s tolerance of %u\n", ++ d->domain_id, cpu_khz, gtsc_khz, khz_diff, ++ disable_vtsc ? "within" : "outside", ++ opt_suse_vtsc_tolerance); ++ } ++ + if ( tsc_mode == TSC_MODE_DEFAULT && host_tsc_is_safe() && +- (d->arch.tsc_khz == cpu_khz || ++ (disable_vtsc || + (is_hvm_domain(d) && + hvm_get_tsc_scaling_ratio(d->arch.tsc_khz))) ) + { |