Re: [PATCH v2] Bug fix - Integer overflow when cpu frequency > u32 max value.

[Elliott Mitchell <ehem+xen@m5p.com>]

On Sun, Dec 18, 2022 at 01:14:07PM +0100, Neowutran wrote:
> xen/x86: prevent overflow with high frequency TSCs
> 
> Promote tsc_khz to a 64-bit type before multiplying by 1000 to avoid a
> '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>

Needing a bit of word-wrapping, but that can be adjusted during commit to
the Xen tree.

This strikes me as urgent for an updated Xen release.  In the past 3
months, both large manufacturers of desktop processors have released
processors with sufficient clock speed to require this patch.  This WILL
trigger *massive* numbers of bug reports very soon.

Similarly I suggest all Linux distributions which distribute Xen will
want to issue updates urgently.


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