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Thu, 30 Jul 2026 05:29:08 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.87.85.9]) by smtpav07.fra02v.mail.ibm.com (Postfix) with ESMTP; Thu, 30 Jul 2026 05:29:08 +0000 (GMT) From: Heiko Carstens To: Alexander Gordeev , Sven Schnelle , Vasily Gorbik , Christian Borntraeger , Harald Freudenberger , Holger Dengler , Vineeth Vijayan , Peter Oberparleiter , Janosch Frank , Claudio Imbrenda , David Hildenbrand , Peter Zijlstra , Herbert Xu Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org Subject: [PATCH v3 2/4] KVM: s390: Remove cond_resched() calls Date: Thu, 30 Jul 2026 07:29:05 +0200 Message-ID: <20260730052907.2607026-3-hca@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260730052907.2607026-1-hca@linux.ibm.com> References: <20260730052907.2607026-1-hca@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Info: AW1haW4tMjYwNzMwMDAzMyBTYWx0ZWRfX1sDzbGCyX0E+ fGXnguuORlvMWQxyXIbJUaidWBZi4JyFHq4AVBYPLefyqeMn3P/mBK7YoikgN/L6Rs28t5U12AQ q2befA/NSFubB5gaanC8jGPQp7kFbk0= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzMwMDAzMyBTYWx0ZWRfX2W7dXIYDF9XC EYKGL8VmOHoWMtmSaEUPBQpFLOMAJ9sv6IKiji/mFtIpxLvpFEMw1RlkG1U6BIXTUC/gLGVRdu1 pbDyrsFw1wIcrshDtd7eAtUJVbLQDcX3ehl1eBDh0EdCS60/qge5RqMJZQOQP94Nc4pAPDjY+JP ZSC0uQmrlvGBFCOaXdLF4ArCpi+GLB8XE9wv3NFrCbFvH42mY+c0SuTXvZfIOr1FxUoMNnmK7KT DR8FfVe/5NZhZrPQPMClAXwtURH+U88wINGwSKWhMUHPzOn3P8/Fh0AMCQhpYvYIh/vZ5u+t4vb fjWp3pZT+did5/VnI3la9YaivsME6q/1L1bBEcL7DNx/HF9KtrKqCsqFwXcNeVEKI3+kg7qXH8W Fw3NmQFMF5HknTtntKsNdAW4srTj9jbt3CnQz6ieIxcn+41LyCUWOLOfWJLaqsvNexu/5p7Yr4W +HBLgSU4EIX5dW2iELw== X-Authority-Analysis: v=2.4 cv=b5WCJNGx c=1 sm=1 tr=0 ts=6a6ae129 cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VnNF1IyMAAAA:8 a=jYxMFs5z4BTu7tBNxzoA:9 X-Proofpoint-GUID: oQi0-eOiG5JV351wBmjqwbH9Yr-kBRji X-Proofpoint-ORIG-GUID: oQi0-eOiG5JV351wBmjqwbH9Yr-kBRji X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-30_01,2026-07-29_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 spamscore=0 adultscore=0 malwarescore=0 impostorscore=0 bulkscore=0 phishscore=0 suspectscore=0 clxscore=1015 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607300033 Since [1] cond_resched() is a no-op on s390. Remove all calls. This also entirely removes uv_call_sched() and replaces all call sites with uv_call(), since both functions are identical after the removal of cond_resched(). [1] commit 7dadeaa6e851 ("sched: Further restrict the preemption modes") Signed-off-by: Heiko Carstens --- arch/s390/include/asm/uv.h | 16 ++-------------- arch/s390/kernel/uv.c | 2 +- arch/s390/kvm/gaccess.c | 8 ++------ arch/s390/kvm/gmap.c | 4 ---- arch/s390/kvm/kvm-s390.c | 1 - arch/s390/kvm/pv.c | 11 +++++------ arch/s390/kvm/vsie.c | 1 - arch/s390/mm/gmap_helpers.c | 1 - drivers/s390/char/uvdevice.c | 6 +++--- 9 files changed, 13 insertions(+), 37 deletions(-) diff --git a/arch/s390/include/asm/uv.h b/arch/s390/include/asm/uv.h index d919e69662f5..89c9bb56c7e6 100644 --- a/arch/s390/include/asm/uv.h +++ b/arch/s390/include/asm/uv.h @@ -454,18 +454,6 @@ static inline int uv_call(unsigned long r1, unsigned long r2) return cc; } -/* Low level uv_call that avoids stalls for long running busy conditions */ -static inline int uv_call_sched(unsigned long r1, unsigned long r2) -{ - int cc; - - do { - cc = __uv_call(r1, r2); - cond_resched(); - } while (cc > 1); - return cc; -} - /* * special variant of uv_call that only transports the cpu or guest * handle and the command, like destroy or verify. @@ -480,7 +468,7 @@ static inline int uv_cmd_nodata(u64 handle, u16 cmd, u16 *rc, u16 *rrc) int cc; WARN(!handle, "No handle provided to Ultravisor call cmd %x\n", cmd); - cc = uv_call_sched(0, (u64)&uvcb); + cc = uv_call(0, (u64)&uvcb); *rc = uvcb.header.rc; *rrc = uvcb.header.rrc; return cc ? -EINVAL : 0; @@ -518,7 +506,7 @@ static inline int uv_list_secrets(struct uv_secret_list *buf, u16 start_idx, .start_idx = start_idx, .list_addr = (u64)buf, }; - int cc = uv_call_sched(0, (u64)&uvcb); + int cc = uv_call(0, (u64)&uvcb); if (rc) *rc = uvcb.header.rc; diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c index a284f98d9716..62841bb00a26 100644 --- a/arch/s390/kernel/uv.c +++ b/arch/s390/kernel/uv.c @@ -831,7 +831,7 @@ int uv_retrieve_secret(u16 secret_idx, u8 *buf, size_t buf_size) .buf_size = buf_size, }; - uv_call_sched(0, (u64)&uvcb); + uv_call(0, (u64)&uvcb); switch (uvcb.header.rc) { case UVC_RC_EXECUTED: diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c index 36102b2727fb..0d389a302a70 100644 --- a/arch/s390/kvm/gaccess.c +++ b/arch/s390/kvm/gaccess.c @@ -151,10 +151,8 @@ static void ipte_lock_simple(struct kvm *kvm) ic = &kvm->arch.sca->ipte_control; old = READ_ONCE(*ic); do { - if (old.k) { - cond_resched(); + if (old.k) goto retry; - } new = old; new.k = 1; } while (!try_cmpxchg(&ic->val, &old.val, new.val)); @@ -189,10 +187,8 @@ static void ipte_lock_siif(struct kvm *kvm) ic = &kvm->arch.sca->ipte_control; old = READ_ONCE(*ic); do { - if (old.kg) { - cond_resched(); + if (old.kg) goto retry; - } new = old; new.k = 1; new.kh++; diff --git a/arch/s390/kvm/gmap.c b/arch/s390/kvm/gmap.c index 8abb4f55b306..3758e4009709 100644 --- a/arch/s390/kvm/gmap.c +++ b/arch/s390/kvm/gmap.c @@ -941,7 +941,6 @@ void gmap_split_huge_pages(struct gmap *gmap) scoped_guard(read_lock, &gmap->kvm->mmu_lock) start = _dat_walk_gfn_range(start, asce_end(gmap->asce), gmap->asce, &ops, DAT_WALK_IGN_HOLES, gmap); - cond_resched(); } while (start); } @@ -963,7 +962,6 @@ static int _gmap_enable_skeys(struct gmap *gmap) do { scoped_guard(write_lock, &gmap->kvm->mmu_lock) start = dat_reset_skeys(gmap->asce, start); - cond_resched(); } while (start); return 0; } @@ -1019,7 +1017,6 @@ int gmap_pv_destroy_range(struct gmap *gmap, gfn_t start, gfn_t end, bool interr DAT_WALK_IGN_HOLES, NULL); if (interruptible && fatal_signal_pending(current)) return -EINTR; - cond_resched(); } while (start && start < end); return 0; } @@ -1138,7 +1135,6 @@ void _gmap_set_cmma_all(struct gmap *gmap, bool dirty) gfn = _dat_walk_gfn_range(gfn, asce_end(gmap->asce), gmap->asce, &ops, DAT_WALK_IGN_HOLES, &gmap->kvm->arch.cmma_dirty_pages); - cond_resched(); } while (gfn); } diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 150b5dd2170e..2ede8f035a38 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -1027,7 +1027,6 @@ static int kvm_s390_set_mem_control(struct kvm *kvm, struct kvm_device_attr *att do { scoped_guard(read_lock, &kvm->mmu_lock) start_gfn = dat_reset_cmma(kvm->arch.gmap->asce, start_gfn); - cond_resched(); } while (start_gfn); ret = 0; break; diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c index 1beacc841ca8..54c17ddb6b11 100644 --- a/arch/s390/kvm/pv.c +++ b/arch/s390/kvm/pv.c @@ -429,7 +429,7 @@ static int kvm_s390_pv_deinit_vm_fast(struct kvm *kvm, u16 *rc, u16 *rrc) }; int cc; - cc = uv_call_sched(0, (u64)&uvcb); + cc = uv_call(0, (u64)&uvcb); if (rc) *rc = uvcb.header.rc; if (rrc) @@ -746,7 +746,7 @@ int kvm_s390_pv_init_vm(struct kvm *kvm, u16 *rc, u16 *rrc) } gmap_split_huge_pages(kvm->arch.gmap); - cc = uv_call_sched(0, (u64)&uvcb); + cc = uv_call(0, (u64)&uvcb); *rc = uvcb.header.rc; *rrc = uvcb.header.rrc; KVM_UV_EVENT(kvm, 3, "PROTVIRT CREATE VM: handle %llx len %llx rc %x rrc %x flags %04x", @@ -832,7 +832,6 @@ int kvm_s390_pv_unpack(struct kvm *kvm, unsigned long addr, unsigned long size, while (offset < size) { ret = unpack_one(kvm, addr, tweak, offset, rc, rrc); if (ret == -EAGAIN) { - cond_resched(); if (fatal_signal_pending(current)) break; continue; @@ -875,7 +874,7 @@ int kvm_s390_pv_dump_cpu(struct kvm_vcpu *vcpu, void *buff, u16 *rc, u16 *rrc) }; int cc; - cc = uv_call_sched(0, (u64)&uvcb); + cc = uv_call(0, (u64)&uvcb); *rc = uvcb.header.rc; *rrc = uvcb.header.rrc; return cc; @@ -959,7 +958,7 @@ int kvm_s390_pv_dump_stor_state(struct kvm *kvm, void __user *buff_user, /* We will loop until the user buffer is filled or an error occurs */ do { /* Get 1MB worth of guest storage state data */ - cc = uv_call_sched(0, (u64)&uvcb); + cc = uv_call(0, (u64)&uvcb); /* All or nothing */ if (cc) { @@ -1037,7 +1036,7 @@ int kvm_s390_pv_dump_complete(struct kvm *kvm, void __user *buff_user, return -ENOMEM; complete.dump_area_origin = (u64)compl_data; - ret = uv_call_sched(0, (u64)&complete); + ret = uv_call(0, (u64)&complete); *rc = complete.header.rc; *rrc = complete.header.rrc; KVM_UV_EVENT(kvm, 3, "PROTVIRT DUMP COMPLETE: rc %x rrc %x", diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c index eea24562e7db..6dcd3b110c17 100644 --- a/arch/s390/kvm/vsie.c +++ b/arch/s390/kvm/vsie.c @@ -1434,7 +1434,6 @@ static int vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) } if (sg) sg = gmap_put(sg); - cond_resched(); } if (sg) sg = gmap_put(sg); diff --git a/arch/s390/mm/gmap_helpers.c b/arch/s390/mm/gmap_helpers.c index 4bf7c9012feb..d564cdefb90f 100644 --- a/arch/s390/mm/gmap_helpers.c +++ b/arch/s390/mm/gmap_helpers.c @@ -272,7 +272,6 @@ static int __gmap_helper_unshare_zeropages(struct mm_struct *mm) * truncation. In that case, the shared zeropage would be gone * and we can simply retry and make progress. */ - cond_resched(); goto retry; } diff --git a/drivers/s390/char/uvdevice.c b/drivers/s390/char/uvdevice.c index e6a264c996ce..4d274a2ee84d 100644 --- a/drivers/s390/char/uvdevice.c +++ b/drivers/s390/char/uvdevice.c @@ -224,7 +224,7 @@ static int uvio_attestation(struct uvio_ioctl_cb *uv_ioctl) if (ret) goto out; - uv_call_sched(0, (u64)uvcb_attest); + uv_call(0, (u64)uvcb_attest); uv_ioctl->uv_rc = uvcb_attest->header.rc; uv_ioctl->uv_rrc = uvcb_attest->header.rrc; @@ -291,7 +291,7 @@ static int uvio_add_secret(struct uvio_ioctl_cb *uv_ioctl) ret = 0; uvcb.addr = (u64)asrcb; - uv_call_sched(0, (u64)&uvcb); + uv_call(0, (u64)&uvcb); uv_ioctl->uv_rc = uvcb.header.rc; uv_ioctl->uv_rrc = uvcb.header.rrc; @@ -457,7 +457,7 @@ static int uvio_retr_secret(struct uvio_ioctl_cb *uv_ioctl) uvcb.buf_addr = (u64)buf; uvcb.buf_size = buf_len; - uv_call_sched(0, (u64)&uvcb); + uv_call(0, (u64)&uvcb); if (copy_to_user((__user void *)uv_ioctl->argument_addr, buf, buf_len)) goto err; -- 2.53.0