diff --git a/Documentation/virt/kvm/devices/s390_flic.rst b/Documentation/virt/kvm/devices/s390_flic.rst index b784f8016748..983c858b444a 100644 --- a/Documentation/virt/kvm/devices/s390_flic.rst +++ b/Documentation/virt/kvm/devices/s390_flic.rst @@ -112,9 +112,20 @@ Groups: mask or unmask the adapter, as specified in mask KVM_S390_IO_ADAPTER_MAP - This is now a no-op. The mapping is purely done by the irq route. + Map an adapter indicator or summary page for long-term pinning so that + interrupt injection can be performed in atomic context. If long-term + pinning is not possible (e.g. file-backed memory), the page is verified + via a short-term pin and the ioctl returns success; interrupt injection + will use the non-atomic irqfd path with short-term pinning on each + interrupt. In Secure Execution mode this is a no-op and the ioctl + returns success. + KVM_S390_IO_ADAPTER_UNMAP - This is now a no-op. The mapping is purely done by the irq route. + Unmap a previously mapped adapter indicator or summary page and release + the long-term pin. If the page was not long-term pinned (e.g. file-backed + memory), the map entry is removed and success is returned; if no prior + map entry exists, -ENOENT is returned. In Secure Execution mode this is + a no-op and the ioctl returns success. KVM_DEV_FLIC_AISM modify the adapter-interruption-suppression mode for a given isc if the diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index eaa34c5bd3c1..c172f9b212d1 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -476,6 +476,11 @@ struct s390_map_info { __u64 guest_addr; __u64 addr; struct page *page; + /* + * True if the page is long-term pinned. False if long-term pinning + * failed and this entry exists only to preserve MAP/UNMAP symmetry. + */ + bool pinned; }; struct s390_io_adapter { diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index 9e3e6b0d72ad..7514d9e2403c 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -2520,8 +2520,22 @@ static int kvm_s390_adapter_map(struct kvm *kvm, unsigned int id, __u64 addr) map->addr = host_addr; map->page = pin_map_page(kvm, host_addr, FOLL_LONGTERM); if (!map->page) { - ret = -EINVAL; - goto out; + /* + * Long-term pinning may fail for memory types such as file-backed + * memory. Verify that short-term pinning succeeds so that the + * non-atomic irqfd path can handle interrupt injection. + */ + map->page = pin_map_page(kvm, host_addr, 0); + if (!map->page) { + ret = -EINVAL; + goto out; + } + unpin_user_page(map->page); + map->page = NULL; + map->pinned = false; + /* Add an entry to preserve MAP/UNMAP symmetry. */ + } else { + map->pinned = true; } spin_lock_irqsave(&adapter->maps_lock, flags); if (adapter->nr_maps < MAX_S390_ADAPTER_MAPS) { @@ -2532,7 +2546,7 @@ static int kvm_s390_adapter_map(struct kvm *kvm, unsigned int id, __u64 addr) ret = -EINVAL; } spin_unlock_irqrestore(&adapter->maps_lock, flags); - if (ret) + if (ret && map->page) unpin_user_page(map->page); out: if (ret) @@ -2546,6 +2560,7 @@ static int kvm_s390_adapter_unmap(struct kvm *kvm, unsigned int id, __u64 addr) struct s390_map_info *map, *tmp, *map_to_free; struct page *map_page_to_put = NULL; u64 map_addr_to_mark = 0; + bool map_pinned = false; unsigned long flags; int found = 0, idx; @@ -2560,6 +2575,7 @@ static int kvm_s390_adapter_unmap(struct kvm *kvm, unsigned int id, __u64 addr) list_del(&map->list); map_page_to_put = map->page; map_addr_to_mark = map->guest_addr; + map_pinned = map->pinned; map_to_free = map; break; } @@ -2568,11 +2584,18 @@ static int kvm_s390_adapter_unmap(struct kvm *kvm, unsigned int id, __u64 addr) 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); + if (map_pinned) { + /* + * Only long-term pinned pages need to be marked dirty + * and released. Fallback entries exist only for + * MAP/UNMAP symmetry. + */ + 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; @@ -2598,11 +2621,13 @@ void kvm_s390_unmap_all_adapters(struct kvm *kvm) 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); + if (map->pinned) { + 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); } } @@ -2929,8 +2954,11 @@ static struct s390_map_info *get_map_info(struct s390_io_adapter *adapter, return NULL; list_for_each_entry(map, &adapter->maps, list) { - if (map->addr == addr) + if (map->addr == addr) { + if (!map->pinned) + return NULL; return map; + } } return NULL; } diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c index 720bb58cabe2..50f5ec79600e 100644 --- a/arch/s390/kvm/pci.c +++ b/arch/s390/kvm/pci.c @@ -190,40 +190,61 @@ static int kvm_zpci_clear_airq(struct zpci_dev *zdev) return cc ? -EIO : 0; } -static inline void unaccount_mem(unsigned long nr_pages) +static inline void unaccount_mem(struct kvm_zdev *kzdev, unsigned long nr_pages) { - struct user_struct *user = get_uid(current_user()); + struct user_struct *user = kzdev->user_account; + struct mm_struct *mm_account = kzdev->mm_account; - if (user) + if (user) { atomic_long_sub(nr_pages, &user->locked_vm); - if (current->mm) - atomic64_sub(nr_pages, ¤t->mm->pinned_vm); + free_uid(user); + kzdev->user_account = NULL; + } + + if (mm_account) { + atomic64_sub(nr_pages, &mm_account->pinned_vm); + mmdrop(mm_account); + kzdev->mm_account = NULL; + } } -static inline int account_mem(unsigned long nr_pages) +static inline int account_mem(struct kvm_zdev *kzdev, unsigned long nr_pages) { struct user_struct *user = get_uid(current_user()); unsigned long page_limit, cur_pages, new_pages; + int rc = 0; page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; cur_pages = atomic_long_read(&user->locked_vm); do { new_pages = cur_pages + nr_pages; - if (new_pages > page_limit) - return -ENOMEM; + if (new_pages > page_limit) { + rc = -ENOMEM; + goto out; + } } while (!atomic_long_try_cmpxchg(&user->locked_vm, &cur_pages, new_pages)); - atomic64_add(nr_pages, ¤t->mm->pinned_vm); + if (current->mm) { + mmgrab(current->mm); + atomic64_add(nr_pages, ¤t->mm->pinned_vm); + } + + kzdev->user_account = user; + kzdev->mm_account = current->mm; return 0; + +out: + free_uid(user); + return rc; } static int kvm_s390_pci_aif_enable(struct zpci_dev *zdev, struct zpci_fib *fib, bool assist) { struct page *pages[1], *aibv_page, *aisb_page = NULL; - unsigned int msi_vecs, idx; + unsigned int msi_vecs, idx, size; struct zpci_gaite *gaite; unsigned long hva, bit; struct kvm *kvm; @@ -237,6 +258,10 @@ static int kvm_s390_pci_aif_enable(struct zpci_dev *zdev, struct zpci_fib *fib, if (zdev->gisa == 0) return -EINVAL; + /* AIF already enabled for the device */ + if (zdev->kzdev->fib.fmt0.aibv != 0) + return -EINVAL; + kvm = zdev->kzdev->kvm; msi_vecs = min_t(unsigned int, fib->fmt0.noi, zdev->max_msi); @@ -246,6 +271,14 @@ static int kvm_s390_pci_aif_enable(struct zpci_dev *zdev, struct zpci_fib *fib, return gisc; /* Replace AIBV address */ + size = BITS_TO_LONGS(msi_vecs + fib->fmt0.aibvo) * sizeof(unsigned long); + npages = DIV_ROUND_UP((fib->fmt0.aibv & ~PAGE_MASK) + size, PAGE_SIZE); + /* AIBV cannot span more than 1 page */ + if (npages > 1) { + rc = -EINVAL; + goto out; + } + idx = srcu_read_lock(&kvm->srcu); hva = gfn_to_hva(kvm, gpa_to_gfn((gpa_t)fib->fmt0.aibv)); npages = pin_user_pages_fast(hva, 1, FOLL_WRITE | FOLL_LONGTERM, pages); @@ -261,6 +294,12 @@ static int kvm_s390_pci_aif_enable(struct zpci_dev *zdev, struct zpci_fib *fib, /* Pin the guest AISB if one was specified */ if (fib->fmt0.sum == 1) { + /* AISB must be dword aligned */ + if (fib->fmt0.aisb & 0x7) { + rc = -EINVAL; + goto unpin1; + } + idx = srcu_read_lock(&kvm->srcu); hva = gfn_to_hva(kvm, gpa_to_gfn((gpa_t)fib->fmt0.aisb)); npages = pin_user_pages_fast(hva, 1, FOLL_WRITE | FOLL_LONGTERM, @@ -275,20 +314,28 @@ static int kvm_s390_pci_aif_enable(struct zpci_dev *zdev, struct zpci_fib *fib, } /* Account for pinned pages, roll back on failure */ - if (account_mem(pcount)) + rc = account_mem(zdev->kzdev, pcount); + if (rc) goto unpin2; /* AISB must be allocated before we can fill in GAITE */ mutex_lock(&aift->aift_lock); bit = airq_iv_alloc_bit(aift->sbv); - if (bit == -1UL) + if (bit == -1UL) { + rc = -ENOMEM; goto unlock; + } zdev->aisb = bit; /* store the summary bit number */ zdev->aibv = airq_iv_create(msi_vecs, AIRQ_IV_DATA | AIRQ_IV_BITLOCK | AIRQ_IV_GUESTVEC, phys_to_virt(fib->fmt0.aibv)); + if (!zdev->aibv) { + rc = -ENOMEM; + goto free_aisb; + } + spin_lock_irq(&aift->gait_lock); gaite = aift->gait + zdev->aisb; @@ -311,21 +358,39 @@ static int kvm_s390_pci_aif_enable(struct zpci_dev *zdev, struct zpci_fib *fib, aift->kzdev[zdev->aisb] = zdev->kzdev; spin_unlock_irq(&aift->gait_lock); - /* Update guest FIB for re-issue */ - fib->fmt0.aisbo = zdev->aisb & 63; - fib->fmt0.aisb = virt_to_phys(aift->sbv->vector) + (zdev->aisb / 64) * 8; - fib->fmt0.isc = gisc; - /* Save some guest fib values in the host for later use */ - zdev->kzdev->fib.fmt0.isc = fib->fmt0.isc; + zdev->kzdev->fib.fmt0.isc = gisc; zdev->kzdev->fib.fmt0.aibv = fib->fmt0.aibv; - mutex_unlock(&aift->aift_lock); /* Issue the clp to setup the irq now */ rc = kvm_zpci_set_airq(zdev); - return rc; + if (!rc) { + mutex_unlock(&aift->aift_lock); + return rc; + } + /* Start cleanup */ + zdev->kzdev->fib.fmt0.isc = 0; + zdev->kzdev->fib.fmt0.aibv = 0; + + spin_lock_irq(&aift->gait_lock); + gaite->count--; + gaite->aisb = 0; + gaite->gisc = 0; + gaite->aisbo = 0; + gaite->gisa = 0; + aift->kzdev[zdev->aisb] = NULL; + spin_unlock_irq(&aift->gait_lock); + + airq_iv_release(zdev->aibv); + zdev->aibv = NULL; + +free_aisb: + airq_iv_free_bit(aift->sbv, zdev->aisb); + zdev->aisb = 0; unlock: + if (pcount > 0) + unaccount_mem(zdev->kzdev, pcount); mutex_unlock(&aift->aift_lock); unpin2: if (fib->fmt0.sum == 1) @@ -396,7 +461,7 @@ static int kvm_s390_pci_aif_disable(struct zpci_dev *zdev, bool force) pcount++; } if (pcount > 0) - unaccount_mem(pcount); + unaccount_mem(kzdev, pcount); out: mutex_unlock(&aift->aift_lock); diff --git a/arch/s390/kvm/pci.h b/arch/s390/kvm/pci.h index ff0972dd5e71..fdf8c7bf4ed0 100644 --- a/arch/s390/kvm/pci.h +++ b/arch/s390/kvm/pci.h @@ -22,6 +22,8 @@ struct kvm_zdev { struct kvm *kvm; struct zpci_fib fib; struct list_head entry; + struct user_struct *user_account; + struct mm_struct *mm_account; }; struct zpci_gaite {