File 63a03e28-x86-high-freq-TSC-overflow.patch of Package xen.31134

Overview Repositories Revisions Requests Users Attributes Meta

File 63a03e28-x86-high-freq-TSC-overflow.patch of Package xen.31134

# Commit ad15a0a8ca2515d8ac58edfc0bc1d3719219cb77
# Date 2022-12-19 11:34:16 +0100
# Author Neowutran <xen@neowutran.ovh>
# Committer Jan Beulich <jbeulich@suse.com>
x86/time: prevent overflow with high frequency TSCs

Make sure tsc_khz is promoted to a 64-bit type before multiplying by
1000 to avoid an 'overflow before widen' bug. Otherwise just above
4.294GHz the value will overflow. Processors with clocks this high are
now in production and require this to work correctly.

Signed-off-by: Neowutran <xen@neowutran.ovh>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -2407,7 +2407,7 @@ int tsc_set_info(struct domain *d,
     case TSC_MODE_ALWAYS_EMULATE:
         d->arch.vtsc_offset = get_s_time() - elapsed_nsec;
         d->arch.tsc_khz = gtsc_khz ?: cpu_khz;
-        set_time_scale(&d->arch.vtsc_to_ns, d->arch.tsc_khz * 1000);
+        set_time_scale(&d->arch.vtsc_to_ns, d->arch.tsc_khz * 1000UL);
 
         /*
          * In default mode use native TSC if the host has safe TSC and

Places

File 63a03e28-x86-high-freq-TSC-overflow.patch of Package xen.31134

Places