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Tue, 25 Jul 2023 14:39:00 +0000 (GMT) From: Ilya Leoshkevich To: Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Heiko Carstens , Vasily Gorbik , Alexander Gordeev Cc: David Hildenbrand , Sven Schnelle , kvm@vger.kernel.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, Jens Freimann , Ilya Leoshkevich Subject: [PATCH v4 2/6] KVM: s390: interrupt: Fix single-stepping into program interrupt handlers Date: Tue, 25 Jul 2023 16:37:17 +0200 Message-ID: <20230725143857.228626-3-iii@linux.ibm.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230725143857.228626-1-iii@linux.ibm.com> References: <20230725143857.228626-1-iii@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: S3BdpMdgfSn2x33RvfGxDJ60QjHGSACu X-Proofpoint-GUID: 0IsjG6cl3HwPnnuX_nOjxBkSV13y0aoq X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.957,Hydra:6.0.591,FMLib:17.11.176.26 definitions=2023-07-25_08,2023-07-25_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 mlxlogscore=999 suspectscore=0 impostorscore=0 mlxscore=0 bulkscore=0 lowpriorityscore=0 priorityscore=1501 malwarescore=0 spamscore=0 adultscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2306200000 definitions=main-2307250128 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Currently, after single-stepping an instruction that generates a specification exception, GDB ends up on the instruction immediately following it. The reason is that vcpu_post_run() injects the interrupt and sets KVM_GUESTDBG_EXIT_PENDING, causing a KVM_SINGLESTEP exit. The interrupt is not delivered, however, therefore userspace sees the address of the next instruction. Fix by letting the __vcpu_run() loop go into the next iteration, where vcpu_pre_run() delivers the interrupt and sets KVM_GUESTDBG_EXIT_PENDING. Reviewed-by: David Hildenbrand Signed-off-by: Ilya Leoshkevich Reviewed-by: Claudio Imbrenda --- arch/s390/kvm/intercept.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c index 954d39adf85c..e54496740859 100644 --- a/arch/s390/kvm/intercept.c +++ b/arch/s390/kvm/intercept.c @@ -228,6 +228,21 @@ static int handle_itdb(struct kvm_vcpu *vcpu) #define per_event(vcpu) (vcpu->arch.sie_block->iprcc & PGM_PER) +static bool should_handle_per_event(const struct kvm_vcpu *vcpu) +{ + if (!guestdbg_enabled(vcpu) || !per_event(vcpu)) + return false; + if (guestdbg_sstep_enabled(vcpu) && + vcpu->arch.sie_block->iprcc != PGM_PER) { + /* + * __vcpu_run() will exit after delivering the concurrently + * indicated condition. + */ + return false; + } + return true; +} + static int handle_prog(struct kvm_vcpu *vcpu) { psw_t psw; @@ -242,7 +257,7 @@ static int handle_prog(struct kvm_vcpu *vcpu) if (kvm_s390_pv_cpu_is_protected(vcpu)) return -EOPNOTSUPP; - if (guestdbg_enabled(vcpu) && per_event(vcpu)) { + if (should_handle_per_event(vcpu)) { rc = kvm_s390_handle_per_event(vcpu); if (rc) return rc;