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Tue, 5 May 2026 17:37:30 +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 v5 1/4] KVM: s390: Add map/unmap ioctl and clean mappings post-guest Date: Tue, 5 May 2026 19:37:25 +0200 Message-ID: <20260505173728.160562-2-freimuth@linux.ibm.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260505173728.160562-1-freimuth@linux.ibm.com> References: <20260505173728.160562-1-freimuth@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@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-Details-Enc: AW1haW4tMjYwNTA1MDE3MSBTYWx0ZWRfX8nLjASfq4cgn 7ZnV+tjVmprJMPGIm3AQhvo3hYijpqt0M2ugxlRuLyDJ/fSBJDWgsBTuNUd0K/0lC/8sb2zALkX oG78cwPjx6oPKud1dPbYWyJ8W9RJmZu/2bptKzqjRjYv0BcGw564NCpz18CWz0CrYh3qDc/mTF+ mBqqCIVL+xW/VIzoPRRkKjiUvL7OZ1TgJ8Kv5FC60txSS4Kd3aTPXswK8sgm4KdqfkfHSGaYvTe wTR7KfwGlJasGJEDDl9SlZwoao22/2Sn99vGx+XXdp0dGrKbl5Jr5Wt5P05rFGjfqWNY9RuT2Lu DUTxBzKkZG/Ka21dP7Z7kQ8uyJtQXcaBC+QnPXUKkeQ09UymEWp06a+TaX39GUrfTUbPya1u30K d6toWGbp8HC+H5DgRMmI5vlAKvNQzpx8bea0hDcKnZ35YO8eIao7yv2nbSEgetYwgXv/uwRSFCC I1ve47MAh2t3Sb9MwXA== X-Proofpoint-ORIG-GUID: pUpiFsPosS4wyeuw7LkHVv7-0Yqu1rxn X-Proofpoint-GUID: pUpiFsPosS4wyeuw7LkHVv7-0Yqu1rxn X-Authority-Analysis: v=2.4 cv=ctWrVV4i c=1 sm=1 tr=0 ts=69fa2add cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=NGcC8JguVDcA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VnNF1IyMAAAA:8 a=8ZgC-7A039QE7m0hxJcA:9 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=2026-05-05_02,2026-04-30_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 lowpriorityscore=0 adultscore=0 clxscore=1015 suspectscore=0 impostorscore=0 spamscore=0 malwarescore=0 phishscore=0 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2604200000 definitions=main-2605050171 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 | 190 ++++++++++++++++++++++++++----- arch/s390/kvm/kvm-s390.c | 8 ++ arch/s390/kvm/kvm-s390.h | 2 + 4 files changed, 176 insertions(+), 29 deletions(-) diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index 8a4f4a39f7a2..fbb2406b31d2 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; + raw_spinlock_t maps_lock; + struct list_head maps; + unsigned int nr_maps; }; #define MAX_S390_IO_ADAPTERS ((MAX_ISC + 1) * 8) diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index 07f59c3b9a7b..a9b418996225 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -2429,6 +2429,9 @@ static int register_io_adapter(struct kvm_device *dev, if (!adapter) return -ENOMEM; + INIT_LIST_HEAD(&adapter->maps); + raw_spin_lock_init(&adapter->maps_lock); + adapter->nr_maps = 0; adapter->id = adapter_info.id; adapter->isc = adapter_info.isc; adapter->maskable = adapter_info.maskable; @@ -2453,12 +2456,151 @@ int kvm_s390_mask_adapter(struct kvm *kvm, unsigned int id, bool masked) return ret; } +static struct page *pin_map_page(struct kvm *kvm, u64 uaddr, + unsigned int gup_flags) +{ + struct mm_struct *mm = kvm->mm; + struct page *page = NULL; + int locked = 1; + + if (mmget_not_zero(mm)) { + mmap_read_lock(mm); + pin_user_pages_remote(mm, uaddr, 1, FOLL_WRITE | gup_flags, + &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 addr) +{ + struct s390_io_adapter *adapter = get_io_adapter(kvm, id); + struct s390_map_info *map; + unsigned long flags; + __u64 host_addr; + int ret, idx; + + if (!adapter || !addr) + return -EINVAL; + + map = kzalloc_obj(*map, GFP_KERNEL_ACCOUNT); + if (!map) + return -ENOMEM; + + INIT_LIST_HEAD(&map->list); + idx = srcu_read_lock(&kvm->srcu); + host_addr = gpa_to_hva(kvm, addr); + if (kvm_is_error_hva(host_addr)) { + srcu_read_unlock(&kvm->srcu, idx); + ret = -EFAULT; + goto out; + } + srcu_read_unlock(&kvm->srcu, idx); + map->guest_addr = addr; + map->addr = host_addr; + map->page = pin_map_page(kvm, host_addr, FOLL_LONGTERM); + if (!map->page) { + ret = -EINVAL; + goto out; + } + raw_spin_lock_irqsave(&adapter->maps_lock, flags); + if (adapter->nr_maps < MAX_S390_ADAPTER_MAPS) { + list_add_tail(&map->list, &adapter->maps); + adapter->nr_maps++; + ret = 0; + } else { + ret = -EINVAL; + } + raw_spin_unlock_irqrestore(&adapter->maps_lock, flags); + if (ret) + unpin_user_page(map->page); +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 = get_io_adapter(kvm, id); + struct s390_map_info *map, *tmp, *map_to_free; + struct page *map_page_to_put = NULL; + u64 map_addr_to_mark = 0; + unsigned long flags; + int found = 0, idx; + + if (!adapter || !addr) + return -EINVAL; + + raw_spin_lock_irqsave(&adapter->maps_lock, flags); + list_for_each_entry_safe(map, tmp, &adapter->maps, list) { + if (map->guest_addr == addr) { + found = 1; + adapter->nr_maps--; + list_del(&map->list); + map_page_to_put = map->page; + map_addr_to_mark = map->guest_addr; + map_to_free = map; + break; + } + } + raw_spin_unlock_irqrestore(&adapter->maps_lock, flags); + + if (found) { + kfree(map_to_free); + idx = srcu_read_lock(&kvm->srcu); + mark_page_dirty(kvm, map_addr_to_mark >> PAGE_SHIFT); + set_page_dirty_lock(map_page_to_put); + srcu_read_unlock(&kvm->srcu, idx); + unpin_user_page(map_page_to_put); + } + + return found ? 0 : -ENOENT; +} + +void kvm_s390_unmap_all_adapters(struct kvm *kvm) +{ + struct s390_map_info *map, *tmp; + unsigned long flags; + int i, idx; + + for (i = 0; i < MAX_S390_IO_ADAPTERS; i++) { + struct s390_io_adapter *adapter = kvm->arch.adapters[i]; + LIST_HEAD(local_list); + + if (!adapter) + continue; + + raw_spin_lock_irqsave(&adapter->maps_lock, flags); + list_splice_init(&adapter->maps, &local_list); + adapter->nr_maps = 0; + raw_spin_unlock_irqrestore(&adapter->maps_lock, flags); + + list_for_each_entry_safe(map, tmp, &local_list, list) { + list_del(&map->list); + idx = srcu_read_lock(&kvm->srcu); + mark_page_dirty(kvm, map->guest_addr >> PAGE_SHIFT); + set_page_dirty_lock(map->page); + srcu_read_unlock(&kvm->srcu, idx); + unpin_user_page(map->page); + kfree(map); + } + } +} + void kvm_s390_destroy_adapters(struct kvm *kvm) { int i; - for (i = 0; i < MAX_S390_IO_ADAPTERS; i++) + kvm_s390_unmap_all_adapters(kvm); + + for (i = 0; i < MAX_S390_IO_ADAPTERS; i++) { kfree(kvm->arch.adapters[i]); + kvm->arch.adapters[i] = NULL; + } } static int modify_io_adapter(struct kvm_device *dev, @@ -2480,14 +2622,22 @@ static int modify_io_adapter(struct kvm_device *dev, if (ret > 0) ret = 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 = 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; + } + if (req.type == KVM_S390_IO_ADAPTER_MAP) { + dev->kvm->stat.io_390_adapter_map++; + ret = kvm_s390_adapter_map(dev->kvm, req.id, req.addr); + } else { + dev->kvm->stat.io_390_adapter_unmap++; + ret = kvm_s390_adapter_unmap(dev->kvm, req.id, req.addr); + } + mutex_unlock(&dev->kvm->lock); break; default: ret = -EINVAL; @@ -2733,24 +2883,6 @@ static unsigned long get_ind_bit(__u64 addr, unsigned long bit_nr, bool swap) return swap ? (bit ^ (BITS_PER_LONG - 1)) : bit; } -static struct page *get_map_page(struct kvm *kvm, u64 uaddr) -{ - struct mm_struct *mm = kvm->mm; - struct page *page = NULL; - int locked = 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) @@ -2760,10 +2892,10 @@ static int adapter_indicators_set(struct kvm *kvm, struct page *ind_page, *summary_page; void *map; - ind_page = get_map_page(kvm, adapter_int->ind_addr); + ind_page = pin_map_page(kvm, adapter_int->ind_addr, 0); if (!ind_page) return -1; - summary_page = get_map_page(kvm, adapter_int->summary_addr); + summary_page = pin_map_page(kvm, adapter_int->summary_addr, 0); if (!summary_page) { put_page(ind_page); return -1; @@ -2784,8 +2916,8 @@ static int adapter_indicators_set(struct kvm *kvm, set_page_dirty_lock(summary_page); srcu_read_unlock(&kvm->srcu, idx); - put_page(ind_page); - put_page(summary_page); + unpin_user_page(ind_page); + unpin_user_page(summary_page); return summary_set ? 0 : 1; } diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index e09960c2e6ed..74f453f039a3 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[] = { 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), @@ -2497,6 +2499,11 @@ static int kvm_s390_pv_dmp(struct kvm *kvm, struct kvm_pv_cmd *cmd, return r; } +static void kvm_s390_unmap_all_adapters_pv(struct kvm *kvm) +{ + kvm_s390_unmap_all_adapters(kvm); +} + static int kvm_s390_handle_pv(struct kvm *kvm, struct kvm_pv_cmd *cmd) { const bool need_lock = (cmd->cmd != KVM_PV_ASYNC_CLEANUP_PERFORM); @@ -2513,6 +2520,7 @@ static int kvm_s390_handle_pv(struct kvm *kvm, struct kvm_pv_cmd *cmd) if (kvm_s390_pv_is_protected(kvm)) break; + kvm_s390_unmap_all_adapters_pv(kvm); mmap_write_lock(kvm->mm); /* * Disable creation of new THPs. Existing THPs can stay, they diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h index dc0573b7aa4b..7ba885cb6bd1 100644 --- a/arch/s390/kvm/kvm-s390.h +++ b/arch/s390/kvm/kvm-s390.h @@ -560,6 +560,8 @@ void kvm_s390_gisa_disable(struct kvm *kvm); void kvm_s390_gisa_enable(struct kvm *kvm); int __init kvm_s390_gib_init(u8 nisc); void kvm_s390_gib_destroy(void); +void kvm_s390_unmap_all_adapters(struct kvm *kvm); + /* implemented in guestdbg.c */ void kvm_s390_backup_guest_per_regs(struct kvm_vcpu *vcpu); -- 2.52.0