f9b3d85b1e
* xen/arm: Fully initialise struct membanks_hdr fields
* build: Set DATE to SOURCE_DATE_EPOCH if available (for
reproducible builds)
* x86: Add Support for Paging-Write Feature
* x86/time: introduce command line option to select wallclock
* x86/time: prefer CMOS over EFI_GET_TIME
* xentrace: free CPU mask string before overwriting pointer
* xl: properly dispose of vTPM struct instance
* xl: properly dispose of libxl_dominfo struct instances
* Various documentation fixes and adjustments
* Various MISRA compliance improvements.
OBS-URL: https://build.opensuse.org/package/show/Virtualization/xen?expand=0&rev=871
59 lines
2.2 KiB
Diff
59 lines
2.2 KiB
Diff
suse_vtsc_tolerance=<val>
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Reference: bsc#1026236
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To avoid emulation of vTSC after live migration or save/restore allow
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different clock frequency up to the specified value. If the frequency
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is within the allowed range TSC access by the domU will be performed
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at native speed. Otherwise TSC access will be emulated. It is up to
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the hostadmin to decide how much tolerance all running domUs can
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actually handle. The default is zero tolerance.
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--- a/xen/arch/x86/time.c
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+++ b/xen/arch/x86/time.c
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@@ -47,6 +47,9 @@
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static char __initdata opt_clocksource[10];
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string_param("clocksource", opt_clocksource);
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+static unsigned int __ro_after_init opt_suse_vtsc_tolerance;
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+integer_param("suse_vtsc_tolerance", opt_suse_vtsc_tolerance);
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+
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unsigned long __read_mostly cpu_khz; /* CPU clock frequency in kHz. */
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DEFINE_SPINLOCK(rtc_lock);
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unsigned long pit0_ticks;
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@@ -2926,6 +2929,8 @@ int tsc_set_info(struct domain *d,
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switch ( tsc_mode )
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{
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+ bool disable_vtsc;
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+
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case XEN_CPUID_TSC_MODE_DEFAULT:
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case XEN_CPUID_TSC_MODE_ALWAYS_EMULATE:
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d->arch.vtsc_offset = get_s_time() - elapsed_nsec;
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@@ -2939,8 +2944,25 @@ int tsc_set_info(struct domain *d,
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* When a guest is created, gtsc_khz is passed in as zero, making
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* d->arch.tsc_khz == cpu_khz. Thus no need to check incarnation.
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*/
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+ disable_vtsc = d->arch.tsc_khz == cpu_khz;
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+
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+ if ( tsc_mode == XEN_CPUID_TSC_MODE_DEFAULT && !disable_vtsc &&
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+ opt_suse_vtsc_tolerance && is_hvm_domain(d) )
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+ {
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+ long khz_diff = ABS((long)cpu_khz - gtsc_khz);
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+
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+ disable_vtsc = khz_diff <= opt_suse_vtsc_tolerance;
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+
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+ printk(XENLOG_G_INFO "%pd: host has %lu kHz,"
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+ " domU expects %u kHz,"
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+ " difference of %ld is %s tolerance of %u\n",
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+ d, cpu_khz, gtsc_khz, khz_diff,
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+ disable_vtsc ? "within" : "outside",
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+ opt_suse_vtsc_tolerance);
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+ }
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+
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if ( tsc_mode == XEN_CPUID_TSC_MODE_DEFAULT && host_tsc_is_safe() &&
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- (d->arch.tsc_khz == cpu_khz ||
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+ (disable_vtsc ||
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(is_hvm_domain(d) &&
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hvm_get_tsc_scaling_ratio(d->arch.tsc_khz))) )
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{
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