Subject: Re: linux-next: Tree for Jan 24 (kvm)

From: Sean Christopherson <[email-masked]>
Date: Fri, 24 Jan 2020 13:30:28 -0800

On Fri, Jan 24, 2020 at 12:51:31PM -0800, Randy Dunlap wrote:
> On 1/23/20 10:33 PM, Stephen Rothwell wrote:
> > Hi all,
> > 
> > Changes since 20200123:
> > 
> > The kvm tree gained a conflict against Linus' tree.
> > 
> 
> on i386:
> 
> ../arch/x86/kvm/x86.h:363:16: warning: right shift count >= width of type [-Wshift-count-overflow]

Jim, 

This is due to using "unsigned long data" for kvm_dr7_valid() along with
"return !(data >> 32);" to check for bits being set in 63:32.  Any
objection to fixing the issue by making @data a u64?  Part of me thinks
that's the proper behavior anyways, i.e. the helper is purely a reflection
of the architectural requirements, the caller is responsible for dropping
bits appropriately based on the current mode.

> 
> 
> -- 
> ~Randy
> Reported-by: Randy Dunlap <[email-masked]>