From: Paolo Bonzini <pbonzini@redhat.com>
To: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
Nadav Amit <namit@cs.technion.ac.il>,
Gleb Natapov <gleb@kernel.org>
Subject: Re: [PATCH 8/8] KVM: x86: simplify kvm_apic_map
Date: Fri, 30 Jan 2015 22:15:45 +0100 [thread overview]
Message-ID: <54CBF481.3020201@redhat.com> (raw)
In-Reply-To: <20150130165747.GD27414@potion.redhat.com>
On 30/01/2015 17:57, Radim Krčmář wrote:
> As optimizations go, we could drop the "&" on cid as "cid < 16" is
> checked later, so mode=4 practically does nothing ... Not the best for
> future bugs, but still pretty safe -- only x2APIC can set a value that
> would require the "&" and it can't have valid XAPIC mode, so u32 still
> protects us enough.
>
> *cid = ldr >> mode;
> *lid = ldr & ((1 << mode) - 1);
>
> Which is probably faster a solution where we don't shuffle switch cases
> to jump to x2APIC first. A comparison is at the very bottom [2].
>
> Would that be ok in v2?
Yes, this is okay. Thanks for looking at it!
Paolo
next prev parent reply other threads:[~2015-01-30 21:15 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-29 21:48 [PATCH 0/8] KVM: minor APIC fixes and cleanups Radim Krčmář
2015-01-29 21:48 ` [PATCH 1/8] KVM: x86: return bool from kvm_apic_match*() Radim Krčmář
2015-01-29 22:10 ` Joe Perches
2015-01-30 8:50 ` Paolo Bonzini
2015-01-29 21:48 ` [PATCH 2/8] KVM: x86: cleanup kvm_apic_match_*() Radim Krčmář
2015-01-30 8:52 ` Paolo Bonzini
2015-01-30 13:06 ` Radim Krčmář
2015-02-02 14:26 ` Radim Krčmář
2015-02-02 14:28 ` Paolo Bonzini
2015-02-02 14:30 ` Radim Krčmář
2015-02-02 14:29 ` Radim Krčmář
2015-01-29 21:48 ` [PATCH 3/8] KVM: x86: replace 0 with APIC_DEST_PHYSICAL Radim Krčmář
2015-01-29 21:48 ` [PATCH 4/8] KVM: x86: fix x2apic logical address matching Radim Krčmář
2015-01-29 21:48 ` [PATCH 5/8] KVM: x86: use MDA for interrupt matching Radim Krčmář
2015-01-30 9:03 ` Paolo Bonzini
2015-01-30 13:09 ` Radim Krčmář
2015-01-29 21:48 ` [PATCH 6/8] KVM: x86: allow mixed APIC mode broadcast Radim Krčmář
2015-01-29 21:48 ` [PATCH 7/8] KVM: x86: avoid logical_map when it is invalid Radim Krčmář
2015-01-30 9:19 ` Paolo Bonzini
2015-01-30 14:21 ` Radim Krčmář
2015-01-30 14:21 ` Paolo Bonzini
2015-01-30 9:38 ` Paolo Bonzini
2015-01-30 14:56 ` Radim Krčmář
2015-01-30 15:10 ` Paolo Bonzini
2015-01-30 17:09 ` Radim Krčmář
2015-01-29 21:48 ` [PATCH 8/8] KVM: x86: simplify kvm_apic_map Radim Krčmář
2015-01-30 9:18 ` Paolo Bonzini
2015-01-30 15:14 ` Radim Krčmář
2015-01-30 15:23 ` Paolo Bonzini
2015-01-30 16:57 ` Radim Krčmář
2015-01-30 21:15 ` Paolo Bonzini [this message]
2015-01-30 9:22 ` [PATCH 0/8] KVM: minor APIC fixes and cleanups Paolo Bonzini
2015-01-30 15:20 ` Radim Krčmář
2015-01-30 15:24 ` Paolo Bonzini
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