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From: Claudio Imbrenda <imbrenda@linux.ibm.com>
To: David Hildenbrand <david@redhat.com>
Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org,
	thuth@redhat.com, borntraeger@de.ibm.com, frankja@linux.ibm.com
Subject: Re: [kvm-unit-tests PATCH v7 4/4] s390x: SCLP unit test
Date: Mon, 13 Jan 2020 16:24:39 +0100
Message-ID: <20200113162439.7ae81f84@p-imbrenda> (raw)
In-Reply-To: <3db7eaf7-6020-365b-c849-9961e483352e@redhat.com>

On Mon, 13 Jan 2020 15:43:28 +0100
David Hildenbrand <david@redhat.com> wrote:

> On 13.01.20 15:05, Claudio Imbrenda wrote:
> > On Mon, 13 Jan 2020 14:10:10 +0100
> > David Hildenbrand <david@redhat.com> wrote:
> > 
> > [...]
> >   
> >> :) I'm confused by the fact that you "expect_pgm_int()" but
> >> actually don't expect one ...
> >>
> >> Please enlighten me why this isn't
> >>
> >> +	sclp_mark_busy();
> >> +	h->length = 8;
> >> +	sclp_setup_int();
> >> +
> >> +	asm volatile(
> >> +		"       .insn   rre,0xb2204200,%1,%2\n"  /* servc
> >> %1,%2 */
> >> +		"       ipm     %0\n"
> >> +		"       srl     %0,28"
> >> +		: "=&d" (cc) : "d" (valid_code), "a"
> >> (__pa(pagebuf))
> >> +		: "cc", "memory");
> >> +	if (!cc)
> >> +		sclp_wait_busy();
> >> +	report(cc == 0, "Instruction format ignored bits");
> >>
> >> I feel like I am missing something important.  
> > 
> > because if we take an unexpected pgm interrupt:
> > * the interrupt handler will write stuff on the console using SCLP
> > * it will wait for the busy flag to be cleared before doing so
> > * thus it will hang.
> > 
> > this would be solved by adding special logic to the pgm interrupt
> > handler (as we have discussed in your previous email)
> >   
> 
> I see, so the issue should hold for all SCLP checks where we don't
> expect an exception ... hmmm
 
which is why my wrapper in the unit test is so complicated :)


  reply index

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-10 18:40 [kvm-unit-tests PATCH v7 0/4] s390x: SCLP Unit test Claudio Imbrenda
2020-01-10 18:40 ` [kvm-unit-tests PATCH v7 1/4] s390x: export sclp_setup_int Claudio Imbrenda
2020-01-10 18:40 ` [kvm-unit-tests PATCH v7 2/4] s390x: sclp: add service call instruction wrapper Claudio Imbrenda
2020-01-10 18:40 ` [kvm-unit-tests PATCH v7 3/4] s390x: lib: add SPX and STPX " Claudio Imbrenda
2020-01-13  9:42   ` Janosch Frank
2020-01-13 12:27     ` Claudio Imbrenda
2020-01-13 10:42   ` David Hildenbrand
2020-01-10 18:40 ` [kvm-unit-tests PATCH v7 4/4] s390x: SCLP unit test Claudio Imbrenda
2020-01-13 11:00   ` David Hildenbrand
2020-01-13 12:33     ` Claudio Imbrenda
2020-01-13 12:48       ` David Hildenbrand
2020-01-13 12:58         ` Claudio Imbrenda
2020-01-13 13:10           ` David Hildenbrand
2020-01-13 14:05             ` Claudio Imbrenda
2020-01-13 14:43               ` David Hildenbrand
2020-01-13 15:24                 ` Claudio Imbrenda [this message]
2020-01-13 16:06                   ` David Hildenbrand
2020-01-13 16:17                     ` Claudio Imbrenda
2020-01-15  9:57                       ` David Hildenbrand

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