From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cornelia Huck Subject: Re: [PATCH 01/12] KVM: s390: reverse bit ordering of irqs in pending mask Date: Thu, 18 Jan 2018 17:50:04 +0100 Message-ID: <20180118175004.415614fb.cohuck@redhat.com> References: <20180116200217.211897-1-borntraeger@de.ibm.com> <20180116200217.211897-2-borntraeger@de.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180116200217.211897-2-borntraeger@de.ibm.com> Sender: kvm-owner@vger.kernel.org List-Archive: List-Post: To: Christian Borntraeger Cc: KVM , linux-s390 , Janosch Frank , David Hildenbrand , Michael Mueller List-ID: On Tue, 16 Jan 2018 21:02:06 +0100 Christian Borntraeger wrote: > From: Michael Mueller > > This patch prepares a simplification of bit operations between the irq > pending mask for emulated interrupts and the Interruption Pending Mask > (IPM) which is part of the Guest Interruption State Area (GISA), a feature > that allows interrupt delivery to guests by means of the SIE instruction. > > Without that change, a bit-wise *or* operation on parts of these two masks > would either require a look-up table of size 256 bytes to map the IPM > to the emulated irq pending mask bit orientation (all bits mirrored at half > byte) or a sequence of up to 8 condidional branches to perform tests of > single bit positions. Both options are to reject either by performance or s/to reject/to be rejected/ > space utilization reasons. > > Beyond that this change will be transparent. > > Signed-off-by: Michael Mueller > Reviewed-by: Halil Pasic > Reviewed-by: Pierre Morel > Reviewed-by: Christian Borntraeger > Signed-off-by: Christian Borntraeger > --- > arch/s390/include/asm/kvm_host.h | 54 ++++++++++++++++++++-------------------- > arch/s390/kvm/interrupt.c | 10 ++++---- > 2 files changed, 32 insertions(+), 32 deletions(-) > > diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h > index e16a9f2a44ad..9981721f258f 100644 > --- a/arch/s390/include/asm/kvm_host.h > +++ b/arch/s390/include/asm/kvm_host.h > @@ -409,35 +409,35 @@ struct kvm_vcpu_stat { > #define PGM_PER 0x80 > #define PGM_CRYPTO_OPERATION 0x119 > > -/* irq types in order of priority */ > +/* irq types in ascend order of priorities */ "ascending order of priority"? Otherwise (and with the "reversed order" change), Reviewed-by: Cornelia Huck