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Re: [Qemu-devel] [PATCH 4/7] s390: sclp event support
From: |
Christian Borntraeger |
Subject: |
Re: [Qemu-devel] [PATCH 4/7] s390: sclp event support |
Date: |
Mon, 30 Jul 2012 16:46:47 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux i686; rv:14.0) Gecko/20120714 Thunderbird/14.0 |
On 30/07/12 15:24, Alexander Graf wrote:
Thanks for the review.
Here is just a short answer regarding the interrupt, we will adress the other
comments in a later
mail.
>> void sclp_service_interrupt(uint32_t sccb)
>> {
>> - if (!sccb) {
>> + SCLPEventFacility *ef = sbus->event_facility->instance;
>> + int event_pending = sbus->event_facility->event_pending(ef);
>> +
>> + if (!event_pending && !sccb) {
>> return;
>> }
>
> Uh. So when there's no event pending no sclp call may trigger an interrupt?
No. If there is no event pending AND no sccb was specified, then we have
nothing to report
--> no interrupt.
An service interrupt has a 32bit value as payload. Bits 0-28 (in IBM speak,
31-3 in Linux speak)
contain the sccb address (if any), the other bits are special. The LSB
describes if there are still
events pending.
So an unsolicited interrupt will only set the LSB.
An answer to a service call will always contain the sccb and might have the lsb
set if there are
events pending.
>> - s390_sclp_extint(sccb & ~3);
>> + s390_sclp_extint((sccb & ~3) + event_pending);
>
> event_pending returns a bool, right? Please make this code a bit less magical
> :).
Something like "event_pending?1:0" ?
- Re: [Qemu-devel] [PATCH 7/7] s390: make sclp ascii console the default, (continued)
- Re: [Qemu-devel] [PATCH 7/7] s390: make sclp ascii console the default, Blue Swirl, 2012/07/24
- [Qemu-devel] [PATCH v4 07/07] s390: make sclp ascii console the default, Christian Borntraeger, 2012/07/26
- [Qemu-devel] [PATCH v4 07/07] s390: make sclp ascii console the default, Christian Borntraeger, 2012/07/26
- Re: [Qemu-devel] [PATCH v4 07/07] s390: make sclp ascii console the default, Alexander Graf, 2012/07/30
- Re: [Qemu-devel] [PATCH v4 07/07] s390: make sclp ascii console the default, Christian Borntraeger, 2012/07/31
- Re: [Qemu-devel] [PATCH v4 07/07] s390: make sclp ascii console the default, Alexander Graf, 2012/07/31
[Qemu-devel] [PATCH 4/7] s390: sclp event support, Christian Borntraeger, 2012/07/24
Re: [Qemu-devel] [PATCH 4/7] s390: sclp event support, Andreas Färber, 2012/07/31
[Qemu-devel] [PATCH 6/7] s390: sclp ascii console support, Christian Borntraeger, 2012/07/24
[Qemu-devel] [PATCH 5/7] s390: sclp signal quiesce support, Christian Borntraeger, 2012/07/24
[Qemu-devel] [PATCH 3/7] s390: sclp base support, Christian Borntraeger, 2012/07/24