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 11:53:57 -0400 Message-ID: <31498420-ad49-7fb6-7d13-55513ca0e3d3@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> <4251c5c4-6330-d391-f37c-c57dd268efe9@linux.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4251c5c4-6330-d391-f37c-c57dd268efe9@linux.ibm.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: Harald Freudenberger , Cornelia Huck Cc: 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 05:37 AM, Harald Freudenberger wrote: > On 10.08.2018 10:49, 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. > I can not think of any other reason why the PQAP(TAPQ) would fail > other than the AP instructions are not available at all. However, > the old implementation returned -ENODEV on failure and 0 on > success. The new implementation now returns 1 for success > and 0 for failure. This is just one of a couple of functions related > to ap xxx available. I'll rework them all to return a boolean value > soon. How would you recommend I proceed given I have functions that call this interface that check the rc and I've had to include your patches in this series because of that dependence? >>>>>> + */ >>>>>> +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; >>>>>> +}