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Subject: Re: [PATCH] KVM: LAPIC: ARBPRI is a reserved register for x2APIC
To:     Liran Alon <liran.alon@oracle.com>
Cc:     linux-kernel@vger.kernel.org, kvm@vger.kernel.org
References: <1562328872-27659-1-git-send-email-pbonzini@redhat.com>
 <D76638DF-1934-4B1C-84CD-FFCE11AA175F@oracle.com>
From:   Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <e8926d53-173b-c525-1c6e-36df9315337a@redhat.com>
Date:   Fri, 5 Jul 2019 14:46:10 +0200
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On 05/07/19 14:37, Liran Alon wrote:
>> +	u64 rmask = 0x43ff01ffffffe70cULL;
> Why not rename this to “used_bits_mask” and calculate it properly by macros?
> It seems a lot nicer than having a pre-calculated magic.

Yes, I wanted to do the same but I didn't have time right now.  I am
planning to cleanup after the merge window, but if a patch comes soon I
can apply it instead of course. :)

Something like

#define APIC_VALID_REG_MASK(reg)	(1ull << ((reg) >> 4))
#define APIC_VALID_REGS_MASK(first, count) \
	(APIC_VALID_REG_MASK(first) * (1ull << ((count) - 1)))

followed by

	if (offset > 0x3f0 ||
	    !(valid_regs_mask & APIC_VALID_REG_MASK(offset))

Paolo

> -Liran
>