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From: Christian Borntraeger <borntraeger@de.ibm.com>
To: David Hildenbrand <david@redhat.com>,
	qemu-devel <qemu-devel@nongnu.org>,
	 Cornelia Huck <cohuck@redhat.com>
Cc: Halil Pasic <pasic@linux.ibm.com>,
	qemu-s390x <qemu-s390x@nongnu.org>,
	Marc Hartmayer <mhartmay@linux.ibm.com>,
	Janosch Frank <frankja@linux.ibm.com>,
	Richard Henderson <rth@twiddle.net>
Subject: Re: [PATCH] s390x/pv: Retry ioctls on -EINTR
Date: Fri, 27 Mar 2020 10:54:57 +0100
Message-ID: <2c4613ec-6a56-4288-8aa8-5599f2624c3b@de.ibm.com> (raw)
In-Reply-To: <17439a57-46b1-d4d8-52fc-13516ae1db82@redhat.com>



On 27.03.20 10:49, David Hildenbrand wrote:
> On 27.03.20 10:43, Christian Borntraeger wrote:
>> PV_ENABLE (and maybe others) might return -EINTR when a signal is
>> pending. Let us retry the ioctl in that case.
>>
>> Fixes: 4d226deafc44 ("s390x: protvirt: Support unpack facility")
>> Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
>> Tested-by: Marc Hartmayer <mhartmay@linux.ibm.com>
>> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
>> ---
>>  hw/s390x/pv.c | 6 +++++-
>>  1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/hw/s390x/pv.c b/hw/s390x/pv.c
>> index 8cf5cd2c9b..2758b02c96 100644
>> --- a/hw/s390x/pv.c
>> +++ b/hw/s390x/pv.c
>> @@ -23,7 +23,11 @@ static int __s390_pv_cmd(uint32_t cmd, const char *cmdname, void *data)
>>          .cmd = cmd,
>>          .data = (uint64_t)data,
>>      };
>> -    int rc = kvm_vm_ioctl(kvm_state, KVM_S390_PV_COMMAND, &pv_cmd);
>> +    int rc;
>> +
>> +    do {
>> +        rc  = kvm_vm_ioctl(kvm_state, KVM_S390_PV_COMMAND, &pv_cmd);
>> +    } while (rc == -EINTR);
>>  
>>      if (rc) {
>>          error_report("KVM PV command %d (%s) failed: header rc %x rrc %x "
>>
> 
> I fail to see where that is triggered in the kernel.
> 
> t480s: ~/git/linux/arch/s390/kvm (HEAD losgelöst bei next/master) $ git
> grep "EINTR"
> kvm-s390.c:     if (exit_reason == -EINTR) {
> kvm-s390.c:             return -EINTR;
> kvm-s390.c:             rc = -EINTR;
> vsie.c: if (rc == -EINTR) {
> 
> 
> Can you help me out? Is that documented?

It is related to the kernel patch.
ksm_madvise->unmerge_ksm_pages has

                if (signal_pending(current))
                        err = -ERESTARTSYS;


entry.S will retranslate ERESTARTSYS into -EINTR. 




  reply index

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-27  9:43 Christian Borntraeger
2020-03-27  9:49 ` David Hildenbrand
2020-03-27  9:54   ` Christian Borntraeger [this message]
2020-03-27  9:56     ` David Hildenbrand
2020-03-27  9:58     ` Christian Borntraeger
2020-03-27 10:01       ` David Hildenbrand
2020-03-27  9:49 ` Janosch Frank

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