From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:43528 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726277AbgAMOnh (ORCPT ); Mon, 13 Jan 2020 09:43:37 -0500 Subject: Re: [kvm-unit-tests PATCH v7 4/4] s390x: SCLP unit test References: <20200110184050.191506-1-imbrenda@linux.ibm.com> <20200110184050.191506-5-imbrenda@linux.ibm.com> <8d7fb5c4-9e2c-e28a-16c0-658afcc8178d@redhat.com> <20200113133325.417bf657@p-imbrenda> <1b86b00a-261e-3d8c-fa52-c30e67463ad5@redhat.com> <20200113135832.1c6d3bb8@p-imbrenda> <22b5ce6a-18af-edec-efc6-e03450faddf8@redhat.com> <20200113150504.3fd218d5@p-imbrenda> From: David Hildenbrand Message-ID: <3db7eaf7-6020-365b-c849-9961e483352e@redhat.com> Date: Mon, 13 Jan 2020 15:43:28 +0100 MIME-Version: 1.0 In-Reply-To: <20200113150504.3fd218d5@p-imbrenda> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-s390-owner@vger.kernel.org List-ID: To: Claudio Imbrenda Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org, thuth@redhat.com, borntraeger@de.ibm.com, frankja@linux.ibm.com On 13.01.20 15:05, Claudio Imbrenda wrote: > On Mon, 13 Jan 2020 14:10:10 +0100 > David Hildenbrand 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 -- Thanks, David / dhildenb