From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Krowiak Subject: Re: [PATCH v8 04/22] s390/zcrypt: Integrate ap_asm.h into include/asm/ap.h. Date: Fri, 10 Aug 2018 11:50:07 -0400 Message-ID: <5661f3b9-6b2b-8a50-bc22-97f364f8ea33@linux.ibm.com> References: <1533739472-7172-1-git-send-email-akrowiak@linux.vnet.ibm.com> <1533739472-7172-5-git-send-email-akrowiak@linux.vnet.ibm.com> <20180809110645.33b20c1f.cohuck@redhat.com> <323af125-f078-919c-3117-f9022f5529ae@linux.ibm.com> <20180810104929.6d40edef.cohuck@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180810104929.6d40edef.cohuck@redhat.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: Cornelia Huck Cc: Harald Freudenberger , Tony Krowiak , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, freude@de.ibm.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, borntraeger@de.ibm.com, kwankhede@nvidia.com, bjsdjshi@linux.vnet.ibm.com, pbonzini@redhat.com, alex.williamson@redhat.com, pmorel@linux.vnet.ibm.com, alifm@linux.vnet.ibm.com, mjrosato@linux.vnet.ibm.com, jjherne@linux.vnet.ibm.com, thuth@redhat.com, pasic@linux.vnet.ibm.com, berrange@redhat.com, fiuczy@linux.vnet.ibm.com, buendgen@de.ibm.com, frankja@linux.ibm.com List-ID: On 08/10/2018 04:49 AM, Cornelia Huck wrote: > On Thu, 9 Aug 2018 12:06:56 -0400 > Tony Krowiak wrote: > >> On 08/09/2018 05:17 AM, Harald Freudenberger wrote: >>> On 09.08.2018 11:06, Cornelia Huck wrote: >>>> On Wed, 8 Aug 2018 10:44:14 -0400 >>>> Tony Krowiak wrote: >>>> >>>>> From: Harald Freudenberger >>>>> >>>>> Move all the inline functions from the ap bus header >>>>> file ap_asm.h into the in-kernel api header file >>>>> arch/s390/include/asm/ap.h so that KVM can make use >>>>> of all the low level AP functions. >>>>> >>>>> Signed-off-by: Harald Freudenberger >>>>> Signed-off-by: Christian Borntraeger >>>> You should add your own s-o-b if you are sending on patches written by >>>> others (even if it does not matter in the end, when they are merged >>>> through a different path anyway.) >>>> >>>>> --- >>>>> arch/s390/include/asm/ap.h | 284 ++++++++++++++++++++++++++++++++++++---- >>>>> drivers/s390/crypto/ap_asm.h | 261 ------------------------------------ >>>>> drivers/s390/crypto/ap_bus.c | 21 +--- >>>>> drivers/s390/crypto/ap_bus.h | 1 + >>>>> drivers/s390/crypto/ap_card.c | 1 - >>>>> drivers/s390/crypto/ap_queue.c | 1 - >>>>> 6 files changed, 259 insertions(+), 310 deletions(-) >>>>> delete mode 100644 drivers/s390/crypto/ap_asm.h >>>>> >>>>> diff --git a/arch/s390/include/asm/ap.h b/arch/s390/include/asm/ap.h >>>>> index c1bedb4..046e044 100644 >>>>> --- a/arch/s390/include/asm/ap.h >>>>> +++ b/arch/s390/include/asm/ap.h >>>>> @@ -47,6 +47,50 @@ struct ap_queue_status { >>>>> }; >>>>> >>>>> /** >>>>> + * ap_intructions_available() - Test if AP instructions are available. >>>>> + * >>>>> + * Returns 0 if the AP instructions are installed. >>>> Stumbled over this when I was looking at the usage in patch 7: if I see >>>> a function called '_available' return 0, I'd assume that whatever the >>>> function tests for is *not* available. >>>> >>>> Rather call this function ap_instructions_check_availability() (and >>>> keep the return code convention), or switch this to return 0 if not >>>> available and !0 if available? >>> Good catch, Cony you are right. I'll fix this to return 1 if AP instructions >>> are available and 0 if not. However, this patch will come via Martin's pipe >>> to the Linus Torwald kernel sources. >> Is your intent to simply indicate whether the AP instructions are >> available or >> not; or is the intention to indicate whether the AP instructions are >> available >> and if not, they why? In the former, then I agree that a boolean should be >> returned; however, if the case is the latter, then what you have is fine but >> maybe the function name should be changed as Connie suggests. > So, can this actually fail for any reason other than "instructions not > installed"? Even if it did, the end result is that the instructions are > not usable -- I don't think the "why" would be interesting at that > point. The only case I can think of is if something is hosed and it causes an exception. In that case, should we proceed? > >>>>> + */ >>>>> +static inline int ap_instructions_available(void) >>>>> +{ >>>>> + register unsigned long reg0 asm ("0") = AP_MKQID(0, 0); >>>>> + register unsigned long reg1 asm ("1") = -ENODEV; >>>>> + register unsigned long reg2 asm ("2"); >>>>> + >>>>> + asm volatile( >>>>> + " .long 0xb2af0000\n" /* PQAP(TAPQ) */ >>>>> + "0: la %0,0\n" >>>>> + "1:\n" >>>>> + EX_TABLE(0b, 1b) >>>>> + : "+d" (reg1), "=d" (reg2) >>>>> + : "d" (reg0) >>>>> + : "cc"); >>>>> + return reg1; >>>>> +}