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Thu, 4 Feb 2021 17:10:02 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0ED7EAE057; Thu, 4 Feb 2021 17:10:02 +0000 (GMT) Received: from localhost.localdomain (unknown [9.145.164.237]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 4 Feb 2021 17:10:01 +0000 (GMT) To: Claudio Imbrenda , linux-kernel@vger.kernel.org Cc: borntraeger@de.ibm.com, david@redhat.com, kvm@vger.kernel.org, linux-s390@vger.kernel.org, stable@vger.kernel.org References: <20210202180028.876888-1-imbrenda@linux.ibm.com> <20210202180028.876888-3-imbrenda@linux.ibm.com> From: Janosch Frank Subject: Re: [PATCH v2 2/2] s390/kvm: VSIE: correctly handle MVPG when in VSIE Message-ID: <2e409ab1-1865-d59a-dc89-2d30f2657a38@linux.ibm.com> Date: Thu, 4 Feb 2021 18:10:01 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: <20210202180028.876888-3-imbrenda@linux.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.369,18.0.737 definitions=2021-02-04_09:2021-02-04,2021-02-04 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 mlxlogscore=999 clxscore=1015 phishscore=0 lowpriorityscore=0 spamscore=0 priorityscore=1501 bulkscore=0 impostorscore=0 malwarescore=0 mlxscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2102040104 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/2/21 7:00 PM, Claudio Imbrenda wrote: > Correctly handle the MVPG instruction when issued by a VSIE guest. > > Fixes: a3508fbe9dc6d ("KVM: s390: vsie: initial support for nested virtualization") > Cc: stable@vger.kernel.org > Signed-off-by: Claudio Imbrenda So far the patch looks ok to me and way better to understand than v1, good job > --- > arch/s390/kvm/vsie.c | 94 +++++++++++++++++++++++++++++++++++++++++--- > 1 file changed, 89 insertions(+), 5 deletions(-) > > diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c > index 7db022141db3..2db49749e27b 100644 > --- a/arch/s390/kvm/vsie.c > +++ b/arch/s390/kvm/vsie.c > @@ -416,11 +416,6 @@ static void unshadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) > memcpy((void *)((u64)scb_o + 0xc0), > (void *)((u64)scb_s + 0xc0), 0xf0 - 0xc0); Magic offsets being magic Another item for my todo list. > break; > - case ICPT_PARTEXEC: > - /* MVPG only */ > - memcpy((void *)((u64)scb_o + 0xc0), > - (void *)((u64)scb_s + 0xc0), 0xd0 - 0xc0); > - break; > } > > if (scb_s->ihcpu != 0xffffU) > @@ -982,6 +977,91 @@ static int handle_stfle(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) > return 0; > } > > +static u64 vsie_get_register(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, u8 reg) > +{ > + reg &= 0xf; > + switch (reg) { > + case 15: > + return vsie_page->scb_s.gg15; > + case 14: > + return vsie_page->scb_s.gg14; > + default: > + return vcpu->run->s.regs.gprs[reg]; > + } > +} > + > +static int vsie_handle_mvpg(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) > +{ > + struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; > + unsigned long pei1, pei2, src, dest, mask = PAGE_MASK; > + u64 *pei_block = &vsie_page->scb_o->mcic; > + int edat, rc1, rc2; Can use a src/dst prefix or suffix please? 1/2 is confusing. > + union ctlreg0 cr0; > + > + cr0.val = vcpu->arch.sie_block->gcr[0]; > + edat = cr0.edat && test_kvm_facility(vcpu->kvm, 8); > + if (psw_bits(scb_s->gpsw).eaba == PSW_BITS_AMODE_24BIT) > + mask = 0xfff000; > + else if (psw_bits(scb_s->gpsw).eaba == PSW_BITS_AMODE_31BIT) > + mask = 0x7ffff000; > + > + dest = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 16) & mask; > + src = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 20) & mask; > + > + rc1 = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, dest, &pei1); > + rc2 = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, src, &pei2); > + /* > + * Either everything went well, or something non-critical went wrong > + * e.g. beause of a race. In either case, simply retry. > + */ > + if (rc1 == -EAGAIN || rc2 == -EAGAIN || (!rc1 && !rc2)) { > + retry_vsie_icpt(vsie_page); > + return -EAGAIN; > + } > + /* Something more serious went wrong, propagate the error */ > + if (rc1 < 0) > + return rc1; > + if (rc2 < 0) > + return rc2; > + > + /* The only possible suppressing exception: just deliver it */ > + if (rc1 == PGM_TRANSLATION_SPEC || rc2 == PGM_TRANSLATION_SPEC) { > + clear_vsie_icpt(vsie_page); > + rc1 = kvm_s390_inject_program_int(vcpu, PGM_TRANSLATION_SPEC); > + WARN_ON_ONCE(rc1); > + return 1; > + } > + > + /* > + * Forward the PEI intercept to the guest if it was a page fault, or > + * also for segment and region table faults if EDAT applies. > + */ > + if (edat) { > + rc1 = rc1 == PGM_ASCE_TYPE ? rc1 : 0; > + rc2 = rc2 == PGM_ASCE_TYPE ? rc2 : 0; > + } > + if ((!rc1 || rc1 == PGM_PAGE_TRANSLATION) && (!rc2 || rc2 == PGM_PAGE_TRANSLATION)) { > + pei_block[0] = pei1; > + pei_block[1] = pei2; > + return 1; > + } > + > + retry_vsie_icpt(vsie_page); > + > + /* > + * The host has edat, and the guest does not, or it was an ASCE type > + * exception. The host needs to inject the appropriate DAT interrupts > + * into the guest. > + */ > + if (rc1) > + return inject_fault(vcpu, rc1, dest, 1); > + if (rc2)> + return inject_fault(vcpu, rc2, src, 0); > + > + /* This should never be reached */ BUG()? > + return 0; > +} > + > /* > * Run the vsie on a shadow scb and a shadow gmap, without any further > * sanity checks, handling SIE faults. > @@ -1068,6 +1148,10 @@ static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) > if ((scb_s->ipa & 0xf000) != 0xf000) > scb_s->ipa += 0x1000; > break; > + case ICPT_PARTEXEC: > + if (scb_s->ipa == 0xb254) > + rc = vsie_handle_mvpg(vcpu, vsie_page); > + break; > } > return rc; > } >