From: Peter Xu <peterx@redhat.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
Nitesh Narayan Lal <nitesh@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>
Subject: Re: [PATCH v4 3/6] KVM: X86: Use APIC_DEST_* macros properly in kvm_lapic_irq.dest_mode
Date: Wed, 4 Dec 2019 13:48:44 -0500 [thread overview]
Message-ID: <20191204184844.GA19939@xz-x1> (raw)
In-Reply-To: <20191203222036.GL19877@linux.intel.com>
On Tue, Dec 03, 2019 at 02:20:36PM -0800, Sean Christopherson wrote:
> On Tue, Dec 03, 2019 at 05:15:19PM -0500, Peter Xu wrote:
> > On Tue, Dec 03, 2019 at 02:07:52PM -0800, Sean Christopherson wrote:
> > > On Tue, Dec 03, 2019 at 11:59:00AM -0500, Peter Xu wrote:
> > > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> > > > index b79cd6aa4075..f815c97b1b57 100644
> > > > --- a/arch/x86/include/asm/kvm_host.h
> > > > +++ b/arch/x86/include/asm/kvm_host.h
> > > > @@ -1022,6 +1022,11 @@ struct kvm_lapic_irq {
> > > > bool msi_redir_hint;
> > > > };
> > > >
> > > > +static inline u16 kvm_lapic_irq_dest_mode(bool dest_mode)
> > > > +{
> > > > + return dest_mode ? APIC_DEST_LOGICAL : APIC_DEST_PHYSICAL;
> > >
> > > IMO this belongs in ioapic.c as it's specifically provided for converting
> > > an I/O APIC redirection entry into a local APIC destination mode. Without
> > > the I/O APIC context, %true==APIC_DEST_LOGICAL looks like a completely
> > > arbitrary decision. And if it's in ioapic.c, it can take the union
> > > of a bool, which avoids the casting and shortens the callers. E.g.:
> > >
> > > static u64 ioapic_to_lapic_dest_mode(union kvm_ioapic_redirect_entry *e)
> > > {
> > > return e->fields.dest_mode ? APIC_DEST_LOGICAL : APIC_DEST_PHYSICAL;
> > > }
> > >
> > > The other option would be to use the same approach as delivery_mode and
> > > open code the shift.
> >
> > It's also used for MSI address encodings, please see below [1].
>
> Boooh. How about naming the param "logical_dest_mode" or something else
> with "logical" in the name so that the correctness of the function itself
> is apparent?
Ok, will do. Thanks,
--
Peter Xu
next prev parent reply other threads:[~2019-12-04 18:48 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-03 16:58 [PATCH v4 0/6] KVM: X86: Cleanups on dest_mode and headers Peter Xu
2019-12-03 16:58 ` [PATCH v4 1/6] KVM: X86: Fix kvm_bitmap_or_dest_vcpus() to use irq shorthand Peter Xu
2019-12-03 16:58 ` [PATCH v4 2/6] KVM: X86: Move irrelevant declarations out of ioapic.h Peter Xu
2019-12-03 16:59 ` [PATCH v4 3/6] KVM: X86: Use APIC_DEST_* macros properly in kvm_lapic_irq.dest_mode Peter Xu
2019-12-03 22:07 ` Sean Christopherson
2019-12-03 22:15 ` Peter Xu
2019-12-03 22:20 ` Sean Christopherson
2019-12-04 18:48 ` Peter Xu [this message]
2019-12-03 16:59 ` [PATCH v4 4/6] KVM: X86: Drop KVM_APIC_SHORT_MASK and KVM_APIC_DEST_MASK Peter Xu
2019-12-03 16:59 ` [PATCH v4 5/6] KVM: X86: Fix callers of kvm_apic_match_dest() to use correct macros Peter Xu
2019-12-03 16:59 ` [PATCH v4 6/6] KVM: X86: Conert the last users of "shorthand = 0" to use macros Peter Xu
2019-12-04 16:12 ` Vitaly Kuznetsov
2019-12-04 18:53 ` Peter Xu
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