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Thu, 26 Mar 2026 01:42:50 +0000 (GMT) From: Douglas Freimuth To: borntraeger@linux.ibm.com, imbrenda@linux.ibm.com, frankja@linux.ibm.com, david@kernel.org, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, svens@linux.ibm.com, kvm@vger.kernel.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org Cc: mjrosato@linux.ibm.com, freimuth@linux.ibm.com Subject: [PATCH v2 1/3] KVM: s390: Add map/unmap ioctl and clean mappings post-guest Date: Thu, 26 Mar 2026 02:42:45 +0100 Message-ID: <20260326014247.2085-2-freimuth@linux.ibm.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260326014247.2085-1-freimuth@linux.ibm.com> References: <20260326014247.2085-1-freimuth@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: 7Gb2wnxNpdtcrkuMkOE0wNxK1nZcSuQm X-Authority-Analysis: v=2.4 cv=aMr9aL9m c=1 sm=1 tr=0 ts=69c48f1d cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=Yq5XynenixoA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VnNF1IyMAAAA:8 a=axuhncQ0aV2LBzSxV34A:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMzI2MDAwOCBTYWx0ZWRfX1hxm6/IdanyJ 7QReBRNbwxDqW9e9WJnkhWqWzyOm3PKk/CH5iqjY7z36YnhGkJnX2ChipO3pTrLdzsfg4iYTHYi N7dMHXnFhGhO7BZvJxRsMcO1lb2HfN2iRLbfFQIXX0x59+RtahWXvxwk3GXM2oMTpdIf3ND9y+o kHYDMWr8QWMOvSWw5W6cqivd2OY0QxrtD6urIBPhb+GzBB3d1u5Qco9YenPzPh2RQVE+WsI6zkR JYRP50xB2cn0QfPTw8s7BJQkgbooX4mIRNTJ3QmoXbCkOA30a1039BQP0oQLfZCtIh6PfQz+YU9 oVLeiwtd5cqlpW4rBo0mrNa6rSoA/AJMabNJXTsRueEqc7wxk8D209ioXHLLuVGGDTgEcfPmce0 XmGeg1Pko0hFJM0uqPYYAXOjRjIGJVKPTylyT0RdqW1+aW3AI2EUaC70/1YEIfJYUedyI0rDhp+ yPqEbJzBsn1mMO/I/qA== X-Proofpoint-GUID: 7Gb2wnxNpdtcrkuMkOE0wNxK1nZcSuQm X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-03-25_07,2026-03-24_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 lowpriorityscore=0 adultscore=0 impostorscore=0 malwarescore=0 suspectscore=0 phishscore=0 priorityscore=1501 bulkscore=0 clxscore=1015 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2603050001 definitions=main-2603260008 Content-Type: text/plain; charset="utf-8" S390 needs map/unmap ioctls, which map the adapter set indicator pages, so the pages can be accessed when interrupts are disabled. The mappings are cleaned up when the guest is removed. Map/Unmap ioctls are fenced in order to avoid the longterm pinning in Secure Execution environments. In Secure Execution environments the path of execution available before this patch is followed. Statistical counters to count map/unmap functions for adapter indicator pages are added. The counters can be used to analyze map/unmap functions in non-Secure Execution environments and similarly can be used to analyze Secure Execution environments where the counters will not be incremented as the adapter indicator pages are not mapped. Signed-off-by: Douglas Freimuth --- arch/s390/include/asm/kvm_host.h | 5 ++ arch/s390/kvm/interrupt.c | 145 +++++++++++++++++++++++++------ arch/s390/kvm/kvm-s390.c | 20 +++++ 3 files changed, 144 insertions(+), 26 deletions(-) diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_h= ost.h index 3039c88daa63..a078420751a1 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -448,6 +448,8 @@ struct kvm_vcpu_arch { struct kvm_vm_stat { struct kvm_vm_stat_generic generic; u64 inject_io; + u64 io_390_adapter_map; + u64 io_390_adapter_unmap; u64 inject_float_mchk; u64 inject_pfault_done; u64 inject_service_signal; @@ -479,6 +481,9 @@ struct s390_io_adapter { bool masked; bool swap; bool suppressible; + spinlock_t maps_lock; + struct list_head maps; + unsigned int nr_maps; }; =20 #define MAX_S390_IO_ADAPTERS ((MAX_ISC + 1) * 8) diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index 7cb8ce833b62..fce170693ff3 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -2426,6 +2426,9 @@ static int register_io_adapter(struct kvm_device *dev, if (!adapter) return -ENOMEM; =20 + INIT_LIST_HEAD(&adapter->maps); + spin_lock_init(&adapter->maps_lock); + adapter->nr_maps =3D 0; adapter->id =3D adapter_info.id; adapter->isc =3D adapter_info.isc; adapter->maskable =3D adapter_info.maskable; @@ -2450,12 +2453,104 @@ int kvm_s390_mask_adapter(struct kvm *kvm, unsigne= d int id, bool masked) return ret; } =20 +static struct page *get_map_page(struct kvm *kvm, u64 uaddr) +{ + struct mm_struct *mm =3D kvm->mm; + struct page *page =3D NULL; + int locked =3D 1; + + if (mmget_not_zero(mm)) { + mmap_read_lock(mm); + get_user_pages_remote(mm, uaddr, 1, FOLL_WRITE, + &page, &locked); + if (locked) + mmap_read_unlock(mm); + mmput(mm); + } + + return page; +} + +static int kvm_s390_adapter_map(struct kvm *kvm, unsigned int id, __u64 ad= dr) +{ + struct s390_io_adapter *adapter =3D get_io_adapter(kvm, id); + struct s390_map_info *map; + unsigned long flags; + int ret; + + if (!adapter || !addr) + return -EINVAL; + + map =3D kzalloc_obj(*map, GFP_KERNEL); + if (!map) + return -ENOMEM; + + map->page =3D get_map_page(kvm, addr); + if (!map->page) { + ret =3D -EINVAL; + goto out; + } + + INIT_LIST_HEAD(&map->list); + map->guest_addr =3D addr; + map->addr =3D addr; + spin_lock_irqsave(&adapter->maps_lock, flags); + if (adapter->nr_maps++ < MAX_S390_ADAPTER_MAPS) { + list_add_tail(&map->list, &adapter->maps); + ret =3D 0; + } else { + put_page(map->page); + ret =3D -EINVAL; + } + spin_unlock_irqrestore(&adapter->maps_lock, flags); +out: + if (ret) + kfree(map); + return ret; +} + +static int kvm_s390_adapter_unmap(struct kvm *kvm, unsigned int id, __u64 = addr) +{ + struct s390_io_adapter *adapter =3D get_io_adapter(kvm, id); + struct s390_map_info *map, *tmp; + unsigned long flags; + int found =3D 0; + + if (!adapter || !addr) + return -EINVAL; + + spin_lock_irqsave(&adapter->maps_lock, flags); + list_for_each_entry_safe(map, tmp, &adapter->maps, list) { + if (map->guest_addr =3D=3D addr) { + found =3D 1; + adapter->nr_maps--; + list_del(&map->list); + put_page(map->page); + kfree(map); + break; + } + } + spin_unlock_irqrestore(&adapter->maps_lock, flags); + + return found ? 0 : -ENOENT; +} + void kvm_s390_destroy_adapters(struct kvm *kvm) { int i; + struct s390_map_info *map, *tmp; =20 - for (i =3D 0; i < MAX_S390_IO_ADAPTERS; i++) + for (i =3D 0; i < MAX_S390_IO_ADAPTERS; i++) { + if (!kvm->arch.adapters[i]) + continue; + list_for_each_entry_safe(map, tmp, + &kvm->arch.adapters[i]->maps, list) { + list_del(&map->list); + put_page(map->page); + kfree(map); + } kfree(kvm->arch.adapters[i]); + } } =20 static int modify_io_adapter(struct kvm_device *dev, @@ -2463,7 +2558,8 @@ static int modify_io_adapter(struct kvm_device *dev, { struct kvm_s390_io_adapter_req req; struct s390_io_adapter *adapter; - int ret; + __u64 host_addr; + int ret, idx; =20 if (copy_from_user(&req, (void __user *)attr->addr, sizeof(req))) return -EFAULT; @@ -2477,14 +2573,29 @@ static int modify_io_adapter(struct kvm_device *dev, if (ret > 0) ret =3D 0; break; - /* - * The following operations are no longer needed and therefore no-ops. - * The gpa to hva translation is done when an IRQ route is set up. The - * set_irq code uses get_user_pages_remote() to do the actual write. - */ case KVM_S390_IO_ADAPTER_MAP: case KVM_S390_IO_ADAPTER_UNMAP: - ret =3D 0; + /* If in Secure Execution mode do not long term pin. */ + mutex_lock(&dev->kvm->lock); + if (kvm_s390_pv_is_protected(dev->kvm)) { + mutex_unlock(&dev->kvm->lock); + return 0; + } + mutex_unlock(&dev->kvm->lock); + idx =3D srcu_read_lock(&dev->kvm->srcu); + host_addr =3D gpa_to_hva(dev->kvm, req.addr); + if (kvm_is_error_hva(host_addr)) { + srcu_read_unlock(&dev->kvm->srcu, idx); + return -EFAULT; + } + srcu_read_unlock(&dev->kvm->srcu, idx); + if (req.type =3D=3D KVM_S390_IO_ADAPTER_MAP) { + dev->kvm->stat.io_390_adapter_map++; + ret =3D kvm_s390_adapter_map(dev->kvm, req.id, host_addr); + } else { + dev->kvm->stat.io_390_adapter_unmap++; + ret =3D kvm_s390_adapter_unmap(dev->kvm, req.id, host_addr); + } break; default: ret =3D -EINVAL; @@ -2730,24 +2841,6 @@ static unsigned long get_ind_bit(__u64 addr, unsigne= d long bit_nr, bool swap) return swap ? (bit ^ (BITS_PER_LONG - 1)) : bit; } =20 -static struct page *get_map_page(struct kvm *kvm, u64 uaddr) -{ - struct mm_struct *mm =3D kvm->mm; - struct page *page =3D NULL; - int locked =3D 1; - - if (mmget_not_zero(mm)) { - mmap_read_lock(mm); - get_user_pages_remote(mm, uaddr, 1, FOLL_WRITE, - &page, &locked); - if (locked) - mmap_read_unlock(mm); - mmput(mm); - } - - return page; -} - static int adapter_indicators_set(struct kvm *kvm, struct s390_io_adapter *adapter, struct kvm_s390_adapter_int *adapter_int) diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index b2c01fa7b852..4b1820bcead1 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -68,6 +68,8 @@ const struct kvm_stats_desc kvm_vm_stats_desc[] =3D { KVM_GENERIC_VM_STATS(), STATS_DESC_COUNTER(VM, inject_io), + STATS_DESC_COUNTER(VM, io_390_adapter_map), + STATS_DESC_COUNTER(VM, io_390_adapter_unmap), STATS_DESC_COUNTER(VM, inject_float_mchk), STATS_DESC_COUNTER(VM, inject_pfault_done), STATS_DESC_COUNTER(VM, inject_service_signal), @@ -2491,6 +2493,23 @@ static int kvm_s390_pv_dmp(struct kvm *kvm, struct k= vm_pv_cmd *cmd, return r; 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Thu, 26 Mar 2026 01:42:51 +0000 (GMT) From: Douglas Freimuth To: borntraeger@linux.ibm.com, imbrenda@linux.ibm.com, frankja@linux.ibm.com, david@kernel.org, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, svens@linux.ibm.com, kvm@vger.kernel.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org Cc: mjrosato@linux.ibm.com, freimuth@linux.ibm.com Subject: [PATCH v2 2/3] KVM: s390: Enable adapter_indicators_set to use mapped pages Date: Thu, 26 Mar 2026 02:42:46 +0100 Message-ID: <20260326014247.2085-3-freimuth@linux.ibm.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260326014247.2085-1-freimuth@linux.ibm.com> References: <20260326014247.2085-1-freimuth@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=IqITsb/g c=1 sm=1 tr=0 ts=69c48f1f cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=Yq5XynenixoA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=uAbxVGIbfxUO_5tXvNgY:22 a=VnNF1IyMAAAA:8 a=3iJqRUJyZzJvN4CYUNoA:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMzI2MDAwOCBTYWx0ZWRfX5t4P4Q8u92qs Ep28azTZJYfEO1VlHd5l/I39FaZBcb/QZYk8aySWA7Q2dITqxReXOSnLvgp6lZ1DVaf7/4/bpHb 9mwtq3eFzimxxiXzO1B9a1yxfTKiTrjeW6pSp44SfKXOIXNJZgUPChtr95MBp1VukOY5Vhohpgs i61EC7ezhoBRGRC4VkLzXRzmGBhmvfLusdhSkdTAfdr92yHUcZgC+qw8AlWdSAunivgyOj4z1gD SigZ4jpIt1Z5x5Pb8Un9aVa/qy9QIyqbQSI6NdbkZb4sww23UOQftFx24gat/4EOWF+xv+qyacM VmTndl2c5WBZMJdFa/sMwgmyq4NG9XR9irv6lUYG0kdWkUUjBSq6F+MVLWMd+VVrHw8UN27jkf6 ye430H0Y3V51CIk5D3cjudT9jlJ8QFO1VmaiS3x4fyw5f+dlXctAr8xlNk2dtMxV+YVGpU0+V1t UwvOmdzzaYLoztGbeIA== X-Proofpoint-GUID: _bxw2XOB4QAa7ZOZfMiAvrfX473at8TC X-Proofpoint-ORIG-GUID: _bxw2XOB4QAa7ZOZfMiAvrfX473at8TC X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-03-25_07,2026-03-24_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 clxscore=1015 spamscore=0 impostorscore=0 suspectscore=0 phishscore=0 bulkscore=0 adultscore=0 priorityscore=1501 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2603050001 definitions=main-2603260008 Content-Type: text/plain; charset="utf-8" The S390 adapter_indicators_set function needs to be able to use mapped=20 pages so that worked can be processed,on a fast path when interrupts are disabled. If adapter indicator pages are not mapped then local mapping is=20 done on a slow path as it is prior to this patch. For example, Secure Execution environments will take the local mapping path as it does prior to this patch. Signed-off-by: Douglas Freimuth --- arch/s390/kvm/interrupt.c | 87 ++++++++++++++++++++++++++++----------- 1 file changed, 62 insertions(+), 25 deletions(-) diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index fce170693ff3..48d05a230416 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -2841,41 +2841,75 @@ static unsigned long get_ind_bit(__u64 addr, unsign= ed long bit_nr, bool swap) return swap ? (bit ^ (BITS_PER_LONG - 1)) : bit; } =20 +static struct s390_map_info *get_map_info(struct s390_io_adapter *adapter, + u64 addr) +{ + struct s390_map_info *map; + + if (!adapter) + return NULL; + + list_for_each_entry(map, &adapter->maps, list) { + if (map->guest_addr =3D=3D addr) + return map; + } + return NULL; +} + static int adapter_indicators_set(struct kvm *kvm, struct s390_io_adapter *adapter, struct kvm_s390_adapter_int *adapter_int) { unsigned long bit; int summary_set, idx; - struct page *ind_page, *summary_page; + struct s390_map_info *ind_info, *summary_info; void *map; + struct page *ind_page, *summary_page; =20 - ind_page =3D get_map_page(kvm, adapter_int->ind_addr); - if (!ind_page) - return -1; - summary_page =3D get_map_page(kvm, adapter_int->summary_addr); - if (!summary_page) { - put_page(ind_page); - return -1; + ind_info =3D get_map_info(adapter, adapter_int->ind_addr); + if (!ind_info) { + ind_page =3D get_map_page(kvm, adapter_int->ind_addr); + if (!ind_page) + return -1; + idx =3D srcu_read_lock(&kvm->srcu); + map =3D page_address(ind_page); + bit =3D get_ind_bit(adapter_int->ind_addr, + adapter_int->ind_offset, adapter->swap); + set_bit(bit, map); + mark_page_dirty(kvm, adapter_int->ind_gaddr >> PAGE_SHIFT); + set_page_dirty_lock(ind_page); + srcu_read_unlock(&kvm->srcu, idx); + } else { + map =3D page_address(ind_info->page); + bit =3D get_ind_bit(ind_info->addr, adapter_int->ind_offset, adapter->sw= ap); + set_bit(bit, map); + } + summary_info =3D get_map_info(adapter, adapter_int->summary_addr); + if (!summary_info) { + summary_page =3D get_map_page(kvm, adapter_int->summary_addr); + if (!summary_page) { + put_page(ind_page); + return -1; + } + idx =3D srcu_read_lock(&kvm->srcu); + map =3D page_address(summary_page); + bit =3D get_ind_bit(adapter_int->summary_addr, + adapter_int->summary_offset, adapter->swap); + summary_set =3D test_and_set_bit(bit, map); + mark_page_dirty(kvm, adapter_int->summary_gaddr >> PAGE_SHIFT); + set_page_dirty_lock(summary_page); + srcu_read_unlock(&kvm->srcu, idx); + } else { + map =3D page_address(summary_info->page); + bit =3D get_ind_bit(summary_info->addr, adapter_int->summary_offset, + adapter->swap); + summary_set =3D test_and_set_bit(bit, map); } =20 - idx =3D srcu_read_lock(&kvm->srcu); - map =3D page_address(ind_page); - bit =3D get_ind_bit(adapter_int->ind_addr, - adapter_int->ind_offset, adapter->swap); - set_bit(bit, map); - mark_page_dirty(kvm, adapter_int->ind_gaddr >> PAGE_SHIFT); - set_page_dirty_lock(ind_page); - map =3D page_address(summary_page); - bit =3D get_ind_bit(adapter_int->summary_addr, - adapter_int->summary_offset, adapter->swap); - summary_set =3D test_and_set_bit(bit, map); - mark_page_dirty(kvm, adapter_int->summary_gaddr >> PAGE_SHIFT); - set_page_dirty_lock(summary_page); - srcu_read_unlock(&kvm->srcu, idx); - - put_page(ind_page); - put_page(summary_page); + if (!ind_info) + put_page(ind_page); + if (!summary_info) + put_page(summary_page); return summary_set ? 0 : 1; } =20 @@ -2890,6 +2924,7 @@ static int set_adapter_int(struct kvm_kernel_irq_rout= ing_entry *e, { int ret; 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Thu, 26 Mar 2026 01:42:52 +0000 (GMT) From: Douglas Freimuth To: borntraeger@linux.ibm.com, imbrenda@linux.ibm.com, frankja@linux.ibm.com, david@kernel.org, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, svens@linux.ibm.com, kvm@vger.kernel.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org Cc: mjrosato@linux.ibm.com, freimuth@linux.ibm.com Subject: [PATCH v2 3/3] KVM: s390: Introducing kvm_arch_set_irq_inatomic fast inject Date: Thu, 26 Mar 2026 02:42:47 +0100 Message-ID: <20260326014247.2085-4-freimuth@linux.ibm.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260326014247.2085-1-freimuth@linux.ibm.com> References: <20260326014247.2085-1-freimuth@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: AeVyZhM2ILgyufrvtDNddjsKDK9S-e5h X-Authority-Analysis: v=2.4 cv=aMr9aL9m c=1 sm=1 tr=0 ts=69c48f20 cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=Yq5XynenixoA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VnNF1IyMAAAA:8 a=9H018nkKpar-jSPhtvkA:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMzI2MDAwOCBTYWx0ZWRfXzdtTwU7E6jaa v5o4XG3k6apN9UvtOoyPVFyNzIJWQkxUIeY3kAQt8txMa5mJKsGLZJKlIdUygTe5jluKnjlUfXb dImdiVc5WsiJkgN4Jt1gOlZ711hwKpqARw2Rw+thnywCSnlCOOvP+xNr9QxueocCTXQ0d2VbWM7 gplB6Vht01V9a0qE5uiSeWi9rxr2uu/pfcQKyeK05zFH8PCtD7fiZbFxHpiBljjwpN/MmeEEJZR qC7ZGSyvHPcnlvn1IPHMlCwFQ9+nEgNCWM8abeeZ32b86L0HOQEXxFrurgKK3fe4bxDmSiard0J K3E8YMsGyg95pKQF5GdVOEUwRHUZmKr73MTGywXfQBl0giPfC2YtkP4CtYWBjULqpRzXp/kpEFH j3fZ8r77mmx5Gjn/tFxdm9q+m1ALknWHZj8opsxzIokG9pqGCFCrK5zJgt6b5Gjm4VBY1nj79ni NfArZB6UDDJlQ5YnsZA== X-Proofpoint-GUID: AeVyZhM2ILgyufrvtDNddjsKDK9S-e5h X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-03-25_07,2026-03-24_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 lowpriorityscore=0 adultscore=0 impostorscore=0 malwarescore=0 suspectscore=0 phishscore=0 priorityscore=1501 bulkscore=0 clxscore=1015 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2603050001 definitions=main-2603260008 Content-Type: text/plain; charset="utf-8" S390 needs a fast path for irq injection, and along those lines we=20 introduce kvm_arch_set_irq_inatomic. Instead of placing all interrupts on the global work queue as it does today, this patch provides a fast path for irq injection. The inatomic fast path cannot lose control since it is running with interrupts disabled. This meant making the following changes that exist on=20 the slow path today. First, the adapter_indicators page needs to be mapped since it is accessed with interrupts disabled, so we added map/unmap functions. Second, access to shared resources between the fast and slow=20 paths needed to be changed from mutex and semaphores to spin_lock's. Finally, the memory allocation on the slow path utilizes GFP_KERNEL_ACCOUNT but we had to implement the fast path with GFP_ATOMIC allocation. Each of these enhancements were required to prevent blocking on the fast inject path. Fencing of Fast Inject in Secure Execution environments is enabled in the patch series by not mapping adapter indicator pages. In Secure Execution environments the path of execution available before this patch is followed. Statistical counters have been added to enable analysis of irq injection on the fast path and slow path including io_390_inatomic, io_flic_inject_airq, io_set_adapter_int and io_390_inatomic_adapter_masked. Signed-off-by: Douglas Freimuth --- arch/s390/include/asm/kvm_host.h | 6 +- arch/s390/kvm/interrupt.c | 154 +++++++++++++++++++++++++++---- arch/s390/kvm/kvm-s390.c | 24 ++++- arch/s390/kvm/kvm-s390.h | 3 +- 4 files changed, 160 insertions(+), 27 deletions(-) diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_h= ost.h index a078420751a1..90b1a19074ce 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -359,7 +359,7 @@ struct kvm_s390_float_interrupt { struct kvm_s390_mchk_info mchk; struct kvm_s390_ext_info srv_signal; int last_sleep_cpu; - struct mutex ais_lock; + spinlock_t ais_lock; u8 simm; u8 nimm; }; @@ -450,6 +450,10 @@ struct kvm_vm_stat { u64 inject_io; u64 io_390_adapter_map; u64 io_390_adapter_unmap; + u64 io_390_inatomic; + u64 io_flic_inject_airq; + u64 io_set_adapter_int; + u64 io_390_inatomic_adapter_masked; u64 inject_float_mchk; u64 inject_pfault_done; u64 inject_service_signal; diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index 48d05a230416..d980b432b173 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -1963,15 +1963,10 @@ static int __inject_vm(struct kvm *kvm, struct kvm_= s390_interrupt_info *inti) } =20 int kvm_s390_inject_vm(struct kvm *kvm, - struct kvm_s390_interrupt *s390int) + struct kvm_s390_interrupt *s390int, struct kvm_s390_interrupt_inf= o *inti) { - struct kvm_s390_interrupt_info *inti; int rc; =20 - inti =3D kzalloc_obj(*inti, GFP_KERNEL_ACCOUNT); - if (!inti) - return -ENOMEM; - inti->type =3D s390int->type; switch (inti->type) { case KVM_S390_INT_VIRTIO: @@ -2284,6 +2279,7 @@ static int flic_ais_mode_get_all(struct kvm *kvm, str= uct kvm_device_attr *attr) { struct kvm_s390_float_interrupt *fi =3D &kvm->arch.float_int; struct kvm_s390_ais_all ais; + unsigned long flags; =20 if (attr->attr < sizeof(ais)) return -EINVAL; @@ -2291,10 +2287,10 @@ static int flic_ais_mode_get_all(struct kvm *kvm, s= truct kvm_device_attr *attr) if (!test_kvm_facility(kvm, 72)) return -EOPNOTSUPP; =20 - mutex_lock(&fi->ais_lock); + spin_lock_irqsave(&fi->ais_lock, flags); ais.simm =3D fi->simm; ais.nimm =3D fi->nimm; - mutex_unlock(&fi->ais_lock); + spin_unlock_irqrestore(&fi->ais_lock, flags); =20 if (copy_to_user((void __user *)attr->addr, &ais, sizeof(ais))) return -EFAULT; @@ -2632,6 +2628,7 @@ static int modify_ais_mode(struct kvm *kvm, struct kv= m_device_attr *attr) struct kvm_s390_float_interrupt *fi =3D &kvm->arch.float_int; struct kvm_s390_ais_req req; int ret =3D 0; + unsigned long flags; =20 if (!test_kvm_facility(kvm, 72)) return -EOPNOTSUPP; @@ -2648,7 +2645,7 @@ static int modify_ais_mode(struct kvm *kvm, struct kv= m_device_attr *attr) 2 : KVM_S390_AIS_MODE_SINGLE : KVM_S390_AIS_MODE_ALL, req.mode); =20 - mutex_lock(&fi->ais_lock); + spin_lock_irqsave(&fi->ais_lock, flags); switch (req.mode) { case KVM_S390_AIS_MODE_ALL: fi->simm &=3D ~AIS_MODE_MASK(req.isc); @@ -2661,7 +2658,7 @@ static int modify_ais_mode(struct kvm *kvm, struct kv= m_device_attr *attr) default: ret =3D -EINVAL; } - mutex_unlock(&fi->ais_lock); + spin_unlock_irqrestore(&fi->ais_lock, flags); =20 return ret; } @@ -2675,25 +2672,33 @@ static int kvm_s390_inject_airq(struct kvm *kvm, .parm =3D 0, .parm64 =3D isc_to_int_word(adapter->isc), }; + struct kvm_s390_interrupt_info *inti; + unsigned long flags; + int ret =3D 0; =20 + inti =3D kzalloc_obj(*inti, GFP_KERNEL_ACCOUNT); + if (!inti) + return -ENOMEM; + if (!test_kvm_facility(kvm, 72) || !adapter->suppressible) - return kvm_s390_inject_vm(kvm, &s390int); + return kvm_s390_inject_vm(kvm, &s390int, inti); =20 - mutex_lock(&fi->ais_lock); + spin_lock_irqsave(&fi->ais_lock, flags); if (fi->nimm & AIS_MODE_MASK(adapter->isc)) { trace_kvm_s390_airq_suppressed(adapter->id, adapter->isc); + kfree(inti); goto out; } =20 - ret =3D kvm_s390_inject_vm(kvm, &s390int); + ret =3D kvm_s390_inject_vm(kvm, &s390int, inti); if (!ret && (fi->simm & AIS_MODE_MASK(adapter->isc))) { fi->nimm |=3D AIS_MODE_MASK(adapter->isc); trace_kvm_s390_modify_ais_mode(adapter->isc, KVM_S390_AIS_MODE_SINGLE, 2); } out: - mutex_unlock(&fi->ais_lock); + spin_unlock_irqrestore(&fi->ais_lock, flags); return ret; } =20 @@ -2702,6 +2707,8 @@ static int flic_inject_airq(struct kvm *kvm, struct k= vm_device_attr *attr) unsigned int id =3D attr->attr; struct s390_io_adapter *adapter =3D get_io_adapter(kvm, id); =20 + kvm->stat.io_flic_inject_airq++; + if (!adapter) return -EINVAL; =20 @@ -2712,6 +2719,7 @@ static int flic_ais_mode_set_all(struct kvm *kvm, str= uct kvm_device_attr *attr) { struct kvm_s390_float_interrupt *fi =3D &kvm->arch.float_int; struct kvm_s390_ais_all ais; + unsigned long flags; =20 if (!test_kvm_facility(kvm, 72)) return -EOPNOTSUPP; @@ -2719,10 +2727,10 @@ static int flic_ais_mode_set_all(struct kvm *kvm, s= truct kvm_device_attr *attr) if (copy_from_user(&ais, (void __user *)attr->addr, sizeof(ais))) return -EFAULT; =20 - mutex_lock(&fi->ais_lock); + spin_lock_irqsave(&fi->ais_lock, flags); fi->simm =3D ais.simm; fi->nimm =3D ais.nimm; - mutex_unlock(&fi->ais_lock); + spin_unlock_irqrestore(&fi->ais_lock, flags); =20 return 0; } @@ -2865,9 +2873,12 @@ static int adapter_indicators_set(struct kvm *kvm, struct s390_map_info *ind_info, *summary_info; void *map; struct page *ind_page, *summary_page; + unsigned long flags; =20 + spin_lock_irqsave(&adapter->maps_lock, flags); ind_info =3D get_map_info(adapter, adapter_int->ind_addr); if (!ind_info) { + spin_unlock_irqrestore(&adapter->maps_lock, flags); ind_page =3D get_map_page(kvm, adapter_int->ind_addr); if (!ind_page) return -1; @@ -2883,9 +2894,13 @@ static int adapter_indicators_set(struct kvm *kvm, map =3D page_address(ind_info->page); bit =3D get_ind_bit(ind_info->addr, adapter_int->ind_offset, adapter->sw= ap); set_bit(bit, map); + spin_unlock_irqrestore(&adapter->maps_lock, flags); } + + spin_lock_irqsave(&adapter->maps_lock, flags); summary_info =3D get_map_info(adapter, adapter_int->summary_addr); if (!summary_info) { + spin_unlock_irqrestore(&adapter->maps_lock, flags); summary_page =3D get_map_page(kvm, adapter_int->summary_addr); if (!summary_page) { put_page(ind_page); @@ -2904,6 +2919,7 @@ static int adapter_indicators_set(struct kvm *kvm, bit =3D get_ind_bit(summary_info->addr, adapter_int->summary_offset, adapter->swap); summary_set =3D test_and_set_bit(bit, map); + spin_unlock_irqrestore(&adapter->maps_lock, flags); } =20 if (!ind_info) @@ -2913,6 +2929,37 @@ static int adapter_indicators_set(struct kvm *kvm, return summary_set ? 0 : 1; } =20 +static int adapter_indicators_set_fast(struct kvm *kvm, + struct s390_io_adapter *adapter, + struct kvm_s390_adapter_int *adapter_int) +{ + unsigned long bit; + int summary_set; + struct s390_map_info *ind_info, *summary_info; + void *map; + + spin_lock(&adapter->maps_lock); + ind_info =3D get_map_info(adapter, adapter_int->ind_addr); + if (!ind_info) { + spin_unlock(&adapter->maps_lock); + return -EWOULDBLOCK; + } + map =3D page_address(ind_info->page); + bit =3D get_ind_bit(ind_info->addr, adapter_int->ind_offset, adapter->swa= p); + set_bit(bit, map); + summary_info =3D get_map_info(adapter, adapter_int->summary_addr); + if (!summary_info) { + spin_unlock(&adapter->maps_lock); + return -EWOULDBLOCK; + } + map =3D page_address(summary_info->page); + bit =3D get_ind_bit(summary_info->addr, adapter_int->summary_offset, + adapter->swap); + summary_set =3D test_and_set_bit(bit, map); + spin_unlock(&adapter->maps_lock); + return summary_set ? 0 : 1; +} + /* * < 0 - not injected due to error * =3D 0 - coalesced, summary indicator already active @@ -2924,7 +2971,8 @@ static int set_adapter_int(struct kvm_kernel_irq_rout= ing_entry *e, { int ret; struct s390_io_adapter *adapter; - unsigned long flags; + + kvm->stat.io_set_adapter_int++; =20 /* We're only interested in the 0->1 transition. */ if (!level) @@ -2932,9 +2980,7 @@ static int set_adapter_int(struct kvm_kernel_irq_rout= ing_entry *e, adapter =3D get_io_adapter(kvm, e->adapter.adapter_id); if (!adapter) return -1; - spin_lock_irqsave(&adapter->maps_lock, flags); ret =3D adapter_indicators_set(kvm, adapter, &e->adapter); - spin_unlock_irqrestore(&adapter->maps_lock, flags); if ((ret > 0) && !adapter->masked) { ret =3D kvm_s390_inject_airq(kvm, adapter); if (ret =3D=3D 0) @@ -2996,7 +3042,6 @@ int kvm_set_routing_entry(struct kvm *kvm, int idx; =20 switch (ue->type) { - /* we store the userspace addresses instead of the guest addresses */ case KVM_IRQ_ROUTING_S390_ADAPTER: if (kvm_is_ucontrol(kvm)) return -EINVAL; @@ -3587,3 +3632,72 @@ int __init kvm_s390_gib_init(u8 nisc) out: return rc; } + +/* + * kvm_arch_set_irq_inatomic: fast-path for irqfd injection + */ +int kvm_arch_set_irq_inatomic(struct kvm_kernel_irq_routing_entry *e, + struct kvm *kvm, int irq_source_id, int level, + bool line_status) +{ + int ret; + struct s390_io_adapter *adapter; + struct kvm_s390_float_interrupt *fi =3D &kvm->arch.float_int; + struct kvm_s390_interrupt_info *inti; + struct kvm_s390_interrupt s390int =3D { + .type =3D KVM_S390_INT_IO(1, 0, 0, 0), + .parm =3D 0, + }; + + kvm->stat.io_390_inatomic++; + + /* We're only interested in the 0->1 transition. */ + if (!level) + return -EWOULDBLOCK; + if (e->type !=3D KVM_IRQ_ROUTING_S390_ADAPTER) + return -EWOULDBLOCK; + + adapter =3D get_io_adapter(kvm, e->adapter.adapter_id); + if (!adapter) + return -EWOULDBLOCK; + + s390int.parm64 =3D isc_to_int_word(adapter->isc); + ret =3D adapter_indicators_set_fast(kvm, adapter, &e->adapter); + if (ret < 0) + return -EWOULDBLOCK; + if (!ret || adapter->masked) { + kvm->stat.io_390_inatomic_adapter_masked++; + return 0; + } + + inti =3D kzalloc_obj(*inti, GFP_ATOMIC); + if (!inti) + return -EWOULDBLOCK; + + if (!test_kvm_facility(kvm, 72) || !adapter->suppressible) { + ret =3D kvm_s390_inject_vm(kvm, &s390int, inti); + if (ret =3D=3D 0) + return ret; + else + return -EWOULDBLOCK; + } + + spin_lock(&fi->ais_lock); + if (fi->nimm & AIS_MODE_MASK(adapter->isc)) { + trace_kvm_s390_airq_suppressed(adapter->id, adapter->isc); + kfree(inti); + goto out; + } + + ret =3D kvm_s390_inject_vm(kvm, &s390int, inti); + if (!ret && (fi->simm & AIS_MODE_MASK(adapter->isc))) { + fi->nimm |=3D AIS_MODE_MASK(adapter->isc); + trace_kvm_s390_modify_ais_mode(adapter->isc, + KVM_S390_AIS_MODE_SINGLE, 2); + } + goto out; + +out: + spin_unlock(&fi->ais_lock); + return 0; +} diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 4b1820bcead1..c53e25bcfab4 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -70,6 +70,10 @@ const struct kvm_stats_desc kvm_vm_stats_desc[] =3D { STATS_DESC_COUNTER(VM, inject_io), STATS_DESC_COUNTER(VM, io_390_adapter_map), STATS_DESC_COUNTER(VM, io_390_adapter_unmap), + STATS_DESC_COUNTER(VM, io_390_inatomic), + STATS_DESC_COUNTER(VM, io_flic_inject_airq), + STATS_DESC_COUNTER(VM, io_set_adapter_int), + STATS_DESC_COUNTER(VM, io_390_inatomic_adapter_masked), STATS_DESC_COUNTER(VM, inject_float_mchk), STATS_DESC_COUNTER(VM, inject_pfault_done), STATS_DESC_COUNTER(VM, inject_service_signal), @@ -2862,6 +2866,7 @@ int kvm_arch_vm_ioctl(struct file *filp, unsigned int= ioctl, unsigned long arg) void __user *argp =3D (void __user *)arg; struct kvm_device_attr attr; int r; + struct kvm_s390_interrupt_info *inti; =20 switch (ioctl) { case KVM_S390_INTERRUPT: { @@ -2870,7 +2875,10 @@ int kvm_arch_vm_ioctl(struct file *filp, unsigned in= t ioctl, unsigned long arg) r =3D -EFAULT; if (copy_from_user(&s390int, argp, sizeof(s390int))) break; - r =3D kvm_s390_inject_vm(kvm, &s390int); + inti =3D kzalloc_obj(*inti, GFP_KERNEL_ACCOUNT); + if (!inti) + return -ENOMEM; + r =3D kvm_s390_inject_vm(kvm, &s390int, inti); break; } case KVM_CREATE_IRQCHIP: { @@ -3268,7 +3276,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long t= ype) mutex_unlock(&kvm->lock); } =20 - mutex_init(&kvm->arch.float_int.ais_lock); + spin_lock_init(&kvm->arch.float_int.ais_lock); spin_lock_init(&kvm->arch.float_int.lock); for (i =3D 0; i < FIRQ_LIST_COUNT; i++) INIT_LIST_HEAD(&kvm->arch.float_int.lists[i]); @@ -4389,11 +4397,16 @@ int kvm_s390_try_set_tod_clock(struct kvm *kvm, con= st struct kvm_s390_vm_tod_clo return 1; } =20 -static void __kvm_inject_pfault_token(struct kvm_vcpu *vcpu, bool start_to= ken, - unsigned long token) +static int __kvm_inject_pfault_token(struct kvm_vcpu *vcpu, bool start_tok= en, + unsigned long token) { struct kvm_s390_interrupt inti; struct kvm_s390_irq irq; + struct kvm_s390_interrupt_info *inti_mem; + + inti_mem =3D kzalloc_obj(*inti_mem, GFP_KERNEL_ACCOUNT); + if (!inti_mem) + return -ENOMEM; =20 if (start_token) { irq.u.ext.ext_params2 =3D token; @@ -4402,8 +4415,9 @@ static void __kvm_inject_pfault_token(struct kvm_vcpu= *vcpu, bool start_token, } else { inti.type =3D KVM_S390_INT_PFAULT_DONE; inti.parm64 =3D token; - WARN_ON_ONCE(kvm_s390_inject_vm(vcpu->kvm, &inti)); + WARN_ON_ONCE(kvm_s390_inject_vm(vcpu->kvm, &inti, inti_mem)); } + return true; } =20 bool kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu, diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h index bf1d7798c1af..2f2da868a040 100644 --- a/arch/s390/kvm/kvm-s390.h +++ b/arch/s390/kvm/kvm-s390.h @@ -373,7 +373,8 @@ int __must_check kvm_s390_deliver_pending_interrupts(st= ruct kvm_vcpu *vcpu); void kvm_s390_clear_local_irqs(struct kvm_vcpu *vcpu); void kvm_s390_clear_float_irqs(struct kvm *kvm); int __must_check kvm_s390_inject_vm(struct kvm *kvm, - struct kvm_s390_interrupt *s390int); + struct kvm_s390_interrupt *s390int, + struct kvm_s390_interrupt_info *inti); int __must_check kvm_s390_inject_vcpu(struct kvm_vcpu *vcpu, struct kvm_s390_irq *irq); static inline int kvm_s390_inject_prog_irq(struct kvm_vcpu *vcpu, --=20 2.52.0