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[209.132.180.67]) by mx.google.com with ESMTP id q66si53106753pfb.231.2019.01.03.13.46.22; Thu, 03 Jan 2019 13:46:42 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=ibm.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731367AbfACPGs (ORCPT + 99 others); Thu, 3 Jan 2019 10:06:48 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:48228 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726259AbfACPGr (ORCPT ); Thu, 3 Jan 2019 10:06:47 -0500 Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id x03F0EP3030125 for ; Thu, 3 Jan 2019 10:06:46 -0500 Received: from e06smtp02.uk.ibm.com (e06smtp02.uk.ibm.com [195.75.94.98]) by mx0b-001b2d01.pphosted.com with ESMTP id 2psmjus01q-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 03 Jan 2019 10:06:44 -0500 Received: from localhost by e06smtp02.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 3 Jan 2019 15:06:39 -0000 Received: from d06av24.portsmouth.uk.ibm.com (d06av24.portsmouth.uk.ibm.com [9.149.105.60]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x03F6c9L59310110 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 3 Jan 2019 15:06:38 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0680742042; Thu, 3 Jan 2019 15:06:38 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 813AA4203F; Thu, 3 Jan 2019 15:06:37 +0000 (GMT) Received: from [9.152.224.140] (unknown [9.152.224.140]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 3 Jan 2019 15:06:37 +0000 (GMT) Reply-To: pmorel@linux.ibm.com Subject: Re: [PATCH v5 11/15] KVM: s390: restore IAM in get_ipm() when IPM is clean To: Michael Mueller , KVM Mailing List Cc: Linux-S390 Mailing List , linux-kernel@vger.kernel.org, kvm390-list@tuxmaker.boeblingen.de.ibm.com, Martin Schwidefsky , Heiko Carstens , Christian Borntraeger , Janosch Frank , David Hildenbrand , Cornelia Huck , Halil Pasic References: <20181219191756.57973-1-mimu@linux.ibm.com> <20181219191756.57973-12-mimu@linux.ibm.com> From: Pierre Morel Date: Thu, 3 Jan 2019 16:06:37 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20181219191756.57973-12-mimu@linux.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19010315-0008-0000-0000-000002AA283B X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19010315-0009-0000-0000-00002216289A Message-Id: <08327d88-388e-2ffe-9bd0-b0de2e0a0ff3@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-01-03_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1901030133 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 19/12/2018 20:17, Michael Mueller wrote: > The patch adds the parameter irq_flags and allows to > restore the Interruption Alert Mask (IAM) in the GISA > atomically while guaranteeing the IPM is clean. > > The function returns the IPM of the GISA. If the returned > value is 0x00 and the IRQ_FLAG_IAM was set, the IAM has > been restored. > > New irq flag: > IRQ_FLAG_IAM: When set, the IAM is restored if no ISC bit > is set in the IPM, i.e. no new airqs are > pending. The test and restore operations > are done atomically. > > Signed-off-by: Michael Mueller > --- > arch/s390/kvm/interrupt.c | 34 +++++++++++++++++++++++++++++----- > 1 file changed, 29 insertions(+), 5 deletions(-) > > diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c > index 1cc3ad2e6c7e..8307717e3caf 100644 > --- a/arch/s390/kvm/interrupt.c > +++ b/arch/s390/kvm/interrupt.c > @@ -37,6 +37,7 @@ > #define IRQ_FLAG_LOCAL 0x8000 /* include local interruption pending mask */ > #define IRQ_FLAG_FLOATING 0x4000 /* include float interruption pending mask */ > #define IRQ_FLAG_GISA 0x2000 /* include GISA interruption pending mask */ > +#define IRQ_FLAG_IAM 0x0080 /* when set try to restore IAM */ > > #define IRQ_MASK_ALL (IRQ_FLAG_LOCAL | IRQ_FLAG_FLOATING | IRQ_FLAG_GISA) > #define IRQ_MASK_NO_GISA (IRQ_MASK_ALL & ~IRQ_FLAG_GISA) > @@ -253,9 +254,32 @@ static inline void set_ipm_gisc(struct kvm_s390_gisa *gisa, u32 gisc) > set_bit_inv(IPM_BIT_OFFSET + gisc, (unsigned long *) gisa); > } > > -static inline u8 get_ipm(struct kvm_s390_gisa *gisa) > +static inline u8 get_ipm(struct kvm_s390_gisa *gisa, u16 irq_flags) > { > - return READ_ONCE(gisa->ipm); > + u64 word, _word; > + u8 ipm; > + > + if (!(irq_flags & IRQ_FLAG_IAM)) > + return READ_ONCE(gisa->ipm); > + > + do { > + word = READ_ONCE(gisa->u64.word[0]); > + ipm = word >> 24; > + /* If the GISA is in the alert list, return the IPM. */ > + if ((u64)gisa != word >> 32) > + return ipm; > + /* If the IPM is dirty, return the IPM. */ > + if (ipm) > + return ipm; > + /* > + * Try to restore the IAM or loop, if the IPM is dirty > + * again or the GISA has been inserted into the alert list. > + */ > + _word = (word & ~0xffUL) | > + container_of(gisa, struct sie_page2, gisa)->kvm->arch.iam; > + } while (cmpxchg(&gisa->u64.word[0], word, _word) != _word); > + > + return 0; > } Personal opinion, but this function do more than just getting the IPM, shouldn't it be reflected in the function name? > > static inline void clear_ipm_gisc(struct kvm_s390_gisa *gisa, u32 gisc) > @@ -277,7 +301,7 @@ static inline unsigned long pending_irqs(struct kvm_vcpu *vcpu, u16 irq_flags) > if (irq_flags & IRQ_FLAG_FLOATING) > pending_irqs |= vcpu->kvm->arch.float_int.pending_irqs; > if (irq_flags & IRQ_FLAG_GISA) > - pending_irqs |= get_ipm(vcpu->kvm->arch.gisa) << > + pending_irqs |= get_ipm(vcpu->kvm->arch.gisa, irq_flags) << > IRQ_PEND_IO_ISC_7; > return pending_irqs; > } > @@ -1574,7 +1598,7 @@ static int get_top_gisa_isc(struct kvm *kvm, u64 isc_mask, u32 schid) > if (!kvm->arch.gisa) > goto out; > > - active_mask = (isc_mask & get_ipm(kvm->arch.gisa) << 24) << 32; > + active_mask = (isc_mask & get_ipm(kvm->arch.gisa, IRQ_FLAG_IAM) << 24) << 32; why do we need to set the IAM here? > while (active_mask) { > isc = __fls(active_mask) ^ (BITS_PER_LONG - 1); > if (tac_ipm_gisc(kvm->arch.gisa, isc)) > @@ -2060,7 +2084,7 @@ static int get_all_floating_irqs(struct kvm *kvm, u8 __user *usrbuf, u64 len) > max_irqs = len / sizeof(struct kvm_s390_irq); > > if (kvm->arch.gisa && > - get_ipm(kvm->arch.gisa)) { > + get_ipm(kvm->arch.gisa, IRQ_FLAG_IAM)) { and here? > for (i = 0; i <= MAX_ISC; i++) { > if (n == max_irqs) { > /* signal userspace to try again */ > -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany