* [PATCH] s390x/pv: Retry ioctls on -EINTR
@ 2020-03-27 9:43 Christian Borntraeger
2020-03-27 9:49 ` David Hildenbrand
2020-03-27 9:49 ` Janosch Frank
0 siblings, 2 replies; 7+ messages in thread
From: Christian Borntraeger @ 2020-03-27 9:43 UTC (permalink / raw)
To: qemu-devel, Cornelia Huck
Cc: Janosch Frank, David Hildenbrand, Halil Pasic,
Christian Borntraeger, qemu-s390x, Marc Hartmayer,
Richard Henderson
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 "
--
2.25.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [PATCH] s390x/pv: Retry ioctls on -EINTR
2020-03-27 9:43 [PATCH] s390x/pv: Retry ioctls on -EINTR Christian Borntraeger
@ 2020-03-27 9:49 ` David Hildenbrand
2020-03-27 9:54 ` Christian Borntraeger
2020-03-27 9:49 ` Janosch Frank
1 sibling, 1 reply; 7+ messages in thread
From: David Hildenbrand @ 2020-03-27 9:49 UTC (permalink / raw)
To: Christian Borntraeger, qemu-devel, Cornelia Huck
Cc: Halil Pasic, qemu-s390x, Marc Hartmayer, Janosch Frank,
Richard Henderson
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?
--
Thanks,
David / dhildenb
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] s390x/pv: Retry ioctls on -EINTR
2020-03-27 9:49 ` David Hildenbrand
@ 2020-03-27 9:54 ` Christian Borntraeger
2020-03-27 9:56 ` David Hildenbrand
2020-03-27 9:58 ` Christian Borntraeger
0 siblings, 2 replies; 7+ messages in thread
From: Christian Borntraeger @ 2020-03-27 9:54 UTC (permalink / raw)
To: David Hildenbrand, qemu-devel, Cornelia Huck
Cc: Halil Pasic, qemu-s390x, Marc Hartmayer, Janosch Frank,
Richard Henderson
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.
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] s390x/pv: Retry ioctls on -EINTR
2020-03-27 9:54 ` Christian Borntraeger
@ 2020-03-27 9:56 ` David Hildenbrand
2020-03-27 9:58 ` Christian Borntraeger
1 sibling, 0 replies; 7+ messages in thread
From: David Hildenbrand @ 2020-03-27 9:56 UTC (permalink / raw)
To: Christian Borntraeger, qemu-devel, Cornelia Huck
Cc: Halil Pasic, qemu-s390x, Marc Hartmayer, Janosch Frank,
Richard Henderson
On 27.03.20 10:54, Christian Borntraeger wrote:
>
>
> 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.
That's valuable information that should go into the patch description.
Also, the documentation should be updated to reflect this. Not obvious :)
--
Thanks,
David / dhildenb
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] s390x/pv: Retry ioctls on -EINTR
2020-03-27 9:54 ` Christian Borntraeger
2020-03-27 9:56 ` David Hildenbrand
@ 2020-03-27 9:58 ` Christian Borntraeger
2020-03-27 10:01 ` David Hildenbrand
1 sibling, 1 reply; 7+ messages in thread
From: Christian Borntraeger @ 2020-03-27 9:58 UTC (permalink / raw)
To: David Hildenbrand, qemu-devel, Cornelia Huck
Cc: Halil Pasic, qemu-s390x, Marc Hartmayer, Janosch Frank,
Richard Henderson
>> 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.
>
In the end both patches fixes an odd-ball case. Marc had a test running
that in parallel started guests and randomly killing QEMUs with pkill.
The QEMUs did end with
qemu-system-s390x: KVM PV command 0 (KVM_PV_ENABLE) failed: header rc 0 rrc 0 IOCTL rc: -12
instead of
qemu-system-s390x: terminating on signal 15 from pid 26495 (pkill)
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] s390x/pv: Retry ioctls on -EINTR
2020-03-27 9:58 ` Christian Borntraeger
@ 2020-03-27 10:01 ` David Hildenbrand
0 siblings, 0 replies; 7+ messages in thread
From: David Hildenbrand @ 2020-03-27 10:01 UTC (permalink / raw)
To: Christian Borntraeger, qemu-devel, Cornelia Huck
Cc: Halil Pasic, qemu-s390x, Marc Hartmayer, Janosch Frank,
Richard Henderson
On 27.03.20 10:58, Christian Borntraeger wrote:
>>> 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.
>>
>
> In the end both patches fixes an odd-ball case. Marc had a test running
> that in parallel started guests and randomly killing QEMUs with pkill.
> The QEMUs did end with
>
> qemu-system-s390x: KVM PV command 0 (KVM_PV_ENABLE) failed: header rc 0 rrc 0 IOCTL rc: -12
>
> instead of
>
> qemu-system-s390x: terminating on signal 15 from pid 26495 (pkill)
>
I guess the same can happen with a qemu_cpu_kick(), just that the BQL
protects us from that to happen concurrently.
--
Thanks,
David / dhildenb
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] s390x/pv: Retry ioctls on -EINTR
2020-03-27 9:43 [PATCH] s390x/pv: Retry ioctls on -EINTR Christian Borntraeger
2020-03-27 9:49 ` David Hildenbrand
@ 2020-03-27 9:49 ` Janosch Frank
1 sibling, 0 replies; 7+ messages in thread
From: Janosch Frank @ 2020-03-27 9:49 UTC (permalink / raw)
To: Christian Borntraeger, qemu-devel, Cornelia Huck
Cc: Halil Pasic, qemu-s390x, Richard Henderson, Marc Hartmayer,
David Hildenbrand
[-- Attachment #1.1: Type: text/plain, Size: 1215 bytes --]
On 3/27/20 10:43 AM, 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>
Acked-by: Janosch Frank <frankja@linux.vnet.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);
Double whitespace after rc.
> + } while (rc == -EINTR);
>
> if (rc) {
> error_report("KVM PV command %d (%s) failed: header rc %x rrc %x "
>
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^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2020-03-27 10:03 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
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2020-03-27 9:43 [PATCH] s390x/pv: Retry ioctls on -EINTR Christian Borntraeger
2020-03-27 9:49 ` David Hildenbrand
2020-03-27 9:54 ` Christian Borntraeger
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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