From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Krowiak Subject: Re: [PATCH v9 17/22] s390: vfio-ap: zeroize the AP queues. Date: Wed, 15 Aug 2018 16:36:32 -0400 Message-ID: <59fddbc0-49f5-c83b-144f-7390b80dfc9f@linux.ibm.com> References: <1534196899-16987-1-git-send-email-akrowiak@linux.vnet.ibm.com> <1534196899-16987-18-git-send-email-akrowiak@linux.vnet.ibm.com> <20180815182401.4cfa0a78.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: <20180815182401.4cfa0a78.cohuck@redhat.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: Cornelia Huck , Tony Krowiak Cc: 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 08/15/2018 12:24 PM, Cornelia Huck wrote: > On Mon, 13 Aug 2018 17:48:14 -0400 > Tony Krowiak wrote: > > Nit: please drop the leading period in the subject. I assume you mean the ending period? > >> From: Tony Krowiak >> >> Let's call PAPQ(ZAPQ) to zeroize a queue: >> >> * For each queue configured for a mediated matrix device >> when it is released. >> >> Zeroizing a queue resets the queue, clears all pending >> messages for the queue entries and disables adapter interruptions >> associated with the queue. >> >> Signed-off-by: Tony Krowiak >> Reviewed-by: Halil Pasic >> Tested-by: Michael Mueller >> Tested-by: Farhan Ali >> Signed-off-by: Christian Borntraeger >> --- >> drivers/s390/crypto/vfio_ap_ops.c | 25 +++++++++++++++++++++++++ >> drivers/s390/crypto/vfio_ap_private.h | 25 +++++++++++++++++++++++++ >> 2 files changed, 50 insertions(+), 0 deletions(-) >> >> diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h >> index 3e8534b..34f982a 100644 >> --- a/drivers/s390/crypto/vfio_ap_private.h >> +++ b/drivers/s390/crypto/vfio_ap_private.h >> @@ -74,4 +74,29 @@ struct ap_matrix_mdev { >> extern int vfio_ap_mdev_register(void); >> extern void vfio_ap_mdev_unregister(void); >> >> +static inline int vfio_ap_reset_queue(unsigned int apid, unsigned int apqi, >> + unsigned int retry) >> +{ >> + struct ap_queue_status status; >> + >> + do { >> + status = ap_zapq(AP_MKQID(apid, apqi)); >> + switch (status.response_code) { >> + case AP_RESPONSE_NORMAL: >> + return 0; >> + case AP_RESPONSE_RESET_IN_PROGRESS: >> + case AP_RESPONSE_BUSY: >> + msleep(20); >> + break; >> + default: >> + pr_warn("%s: error zeroizing %02x.%04x: response code %d\n", >> + VFIO_AP_MODULE_NAME, apid, apqi, >> + status.response_code); > How can we end up here? Does this mean that we just don't know what to > do with this response, or is this something that should never happen? > (How much sense does it make to print an error?) There are additional response codes that could be returned; for example, in the case of a catastrophic failure such as: The function can not be performed because the AP was somehow deconfigured or the functiona cannot be performed due to a machine check failure that caused the AP path to be removed. It shouldn't happen, but all are possibilities. I can get rid of the message and just return -EIO if you prefer. > >> + return -EIO; >> + } >> + } while (retry--); >> + >> + return -EBUSY; >> +} >> + >> #endif /* _VFIO_AP_PRIVATE_H_ */