From: Neowutran Date: Tue, 20 Dec 2022 12:46:38 +0000 (+0100) Subject: x86/time: prevent overflow with high frequency TSCs X-Git-Tag: archive/raspbian/4.17.1+2-gb773c48e36-1+rpi1~1^2~57^2~15 X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/%22/%22http:/www.example.com/cgi/%22?a=commitdiff_plain;h=a7a26da0b59da7233e6c6f63b180bab131398351;p=xen.git 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 Reviewed-by: Jan Beulich master commit: ad15a0a8ca2515d8ac58edfc0bc1d3719219cb77 master date: 2022-12-19 11:34:16 +0100 --- diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c index b01acd390d..d882b43cf0 100644 --- a/xen/arch/x86/time.c +++ b/xen/arch/x86/time.c @@ -2585,7 +2585,7 @@ 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