From: Sheng Yang <sheng@linux.intel.com>
To: ncmike@ncultra.org
Cc: Avi Kivity <avi@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
kvm@vger.kernel.org
Subject: Re: KVM: Merge MSI handling to kvm_set_irq
Date: Fri, 9 Jan 2009 09:32:47 +0800 [thread overview]
Message-ID: <200901090932.48148.sheng@linux.intel.com> (raw)
In-Reply-To: <20090108135441.GA4628@silverwood.ncultra.org>
On Thursday 08 January 2009 21:54:41 Mike Day wrote:
> On 07/01/09 18:42 +0800, Sheng Yang wrote:
> > Using kvm_set_irq to handle all interrupt injection.
> >
> > Signed-off-by: Sheng Yang <sheng@linux.intel.com>
> > ---
> >
> > +static void gsi_dispatch(struct kvm *kvm, u32 gsi)
>
> ...
>
> > + case IOAPIC_FIXED:
> > + for (vcpu_id = 0; deliver_bitmask != 0; vcpu_id++) {
> > + if (!(deliver_bitmask & (1 << vcpu_id)))
> > + continue;
> > + deliver_bitmask &= ~(1 << vcpu_id);
> > + vcpu = ioapic->kvm->vcpus[vcpu_id];
> > + if (vcpu)
> > + kvm_apic_set_irq(vcpu, vector,
> > + trig_mode);
> > + }
> > + break;
> > + default:
> > + break;
> > + }
>
> In cases such as the for() loop above, which are numerous in the
> patchset, I wonder if using bitops would be slightly better:
>
> case IOAPIC_FIXED:
> while (deliver_bitmask != 0) {
> vcpu_id = ffs(deliver_bitmask);
> __clear_bit(vcpu_id - 1, &deliver_bitmask);
> vcpu = ioapic->kvm->vcpus[vcpu_id - 1];
> if (vcpu)
> kvm_apic_set_irq(vcpu, vector,
> trig_mode);
> } ;
>
>
> I did a quick check and the second example compiles to a more
> consise set of assembler instructions. The current code uses bitops in
> cases like this.
>
Yes, that's what I did for bitmap changing in the following patches. Please
refer to "[PATCH 10/10] KVM: bit ops for deliver_bitmap" I sent before.
--
regards
Yang, Sheng
> Mike
next prev parent reply other threads:[~2009-01-09 1:32 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-07 10:42 [PATCH 0/10][v4]GSI route layer for MSI/MSI-X Sheng Yang
2009-01-07 10:42 ` [PATCH 01/10] KVM: Add a route layer to convert MSI message to GSI Sheng Yang
2009-01-07 16:18 ` Marcelo Tosatti
2009-01-08 7:30 ` Sheng Yang
2009-01-07 10:42 ` [PATCH 02/10] KVM: Using gsi route for MSI device assignment Sheng Yang
2009-01-07 10:42 ` [PATCH 03/10] KVM: Improve MSI dispatch function Sheng Yang
2009-01-07 10:42 ` [PATCH 04/10] KVM: Using ioapic_irqchip() macro for kvm_set_irq Sheng Yang
2009-01-07 10:42 ` [PATCH 05/10] KVM: Merge MSI handling to kvm_set_irq Sheng Yang
2009-01-07 21:39 ` Marcelo Tosatti
2009-01-08 9:24 ` Sheng Yang
2009-01-08 13:54 ` Mike Day
2009-01-09 1:32 ` Sheng Yang [this message]
2009-01-07 10:42 ` [PATCH 06/10] KVM: Split IOAPIC structure Sheng Yang
2009-01-07 10:42 ` [PATCH 07/10] KVM: Unified the delivery of IOAPIC and MSI Sheng Yang
2009-01-07 10:42 ` [PATCH 08/10] KVM: Change API of kvm_ioapic_get_delivery_bitmask Sheng Yang
2009-01-07 10:42 ` [PATCH 09/10] KVM: Update intr delivery func to accept unsigned long* bitmap Sheng Yang
2009-01-08 0:38 ` Marcelo Tosatti
2009-01-07 10:42 ` [PATCH 10/10] KVM: bit ops for deliver_bitmap Sheng Yang
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