Re: [PATCH 2/8] KVM: x86/xen: Introduce kvm_xen_has_64bit_shinfo() macro

[David Woodhouse]

On Sat, 2026-06-06 at 10:30 +0100, David Laight wrote:
> On Fri,  5 Jun 2026 15:17:27 +0100
> David Woodhouse <dwmw2@xxxxxxxxxxxxx> wrote:
> 
> > From: David Woodhouse <dwmw@xxxxxxxxxxxx>
> > 
> > Add a kvm_xen_has_64bit_shinfo() helper macro to replace the repeated
> > pattern of 'IS_ENABLED(CONFIG_64BIT) && kvm->arch.xen.long_mode'
> > throughout the Xen emulation code. The macro uses READ_ONCE() to
> > ensure a consistent snapshot of the flag, which can be changed by
> > another vCPU at any time.
> 
> If another vCPU changes the flag then isn't it all broken?
> The code seems to need the value to be stable.

Do you believe the explanation in patch 4 to be insufficient?

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