diff options
Diffstat (limited to 'arch/s390/kvm/pci.c')
| -rw-r--r-- | arch/s390/kvm/pci.c | 702 |
1 files changed, 702 insertions, 0 deletions
diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c new file mode 100644 index 000000000..ded1af2dd --- /dev/null +++ b/arch/s390/kvm/pci.c @@ -0,0 +1,702 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * s390 kvm PCI passthrough support + * + * Copyright IBM Corp. 2022 + * + * Author(s): Matthew Rosato <mjrosato@linux.ibm.com> + */ + +#include <linux/kvm_host.h> +#include <linux/pci.h> +#include <asm/pci.h> +#include <asm/pci_insn.h> +#include <asm/pci_io.h> +#include <asm/sclp.h> +#include "pci.h" +#include "kvm-s390.h" + +struct zpci_aift *aift; + +static inline int __set_irq_noiib(u16 ctl, u8 isc) +{ + union zpci_sic_iib iib = {{0}}; + + return zpci_set_irq_ctrl(ctl, isc, &iib); +} + +void kvm_s390_pci_aen_exit(void) +{ + unsigned long flags; + struct kvm_zdev **gait_kzdev; + + lockdep_assert_held(&aift->aift_lock); + + /* + * Contents of the aipb remain registered for the life of the host + * kernel, the information preserved in zpci_aipb and zpci_aif_sbv + * in case we insert the KVM module again later. Clear the AIFT + * information and free anything not registered with underlying + * firmware. + */ + spin_lock_irqsave(&aift->gait_lock, flags); + gait_kzdev = aift->kzdev; + aift->gait = NULL; + aift->sbv = NULL; + aift->kzdev = NULL; + spin_unlock_irqrestore(&aift->gait_lock, flags); + + kfree(gait_kzdev); +} + +static int zpci_setup_aipb(u8 nisc) +{ + struct page *page; + int size, rc; + + zpci_aipb = kzalloc(sizeof(union zpci_sic_iib), GFP_KERNEL); + if (!zpci_aipb) + return -ENOMEM; + + aift->sbv = airq_iv_create(ZPCI_NR_DEVICES, AIRQ_IV_ALLOC, NULL); + if (!aift->sbv) { + rc = -ENOMEM; + goto free_aipb; + } + zpci_aif_sbv = aift->sbv; + size = get_order(PAGE_ALIGN(ZPCI_NR_DEVICES * + sizeof(struct zpci_gaite))); + page = alloc_pages(GFP_KERNEL | __GFP_ZERO, size); + if (!page) { + rc = -ENOMEM; + goto free_sbv; + } + aift->gait = (struct zpci_gaite *)page_to_virt(page); + + zpci_aipb->aipb.faisb = virt_to_phys(aift->sbv->vector); + zpci_aipb->aipb.gait = virt_to_phys(aift->gait); + zpci_aipb->aipb.afi = nisc; + zpci_aipb->aipb.faal = ZPCI_NR_DEVICES; + + /* Setup Adapter Event Notification Interpretation */ + if (zpci_set_irq_ctrl(SIC_SET_AENI_CONTROLS, 0, zpci_aipb)) { + rc = -EIO; + goto free_gait; + } + + return 0; + +free_gait: + free_pages((unsigned long)aift->gait, size); +free_sbv: + airq_iv_release(aift->sbv); + zpci_aif_sbv = NULL; +free_aipb: + kfree(zpci_aipb); + zpci_aipb = NULL; + + return rc; +} + +static int zpci_reset_aipb(u8 nisc) +{ + /* + * AEN registration can only happen once per system boot. If + * an aipb already exists then AEN was already registered and + * we can re-use the aipb contents. This can only happen if + * the KVM module was removed and re-inserted. However, we must + * ensure that the same forwarding ISC is used as this is assigned + * during KVM module load. + */ + if (zpci_aipb->aipb.afi != nisc) + return -EINVAL; + + aift->sbv = zpci_aif_sbv; + aift->gait = (struct zpci_gaite *)zpci_aipb->aipb.gait; + + return 0; +} + +int kvm_s390_pci_aen_init(u8 nisc) +{ + int rc = 0; + + /* If already enabled for AEN, bail out now */ + if (aift->gait || aift->sbv) + return -EPERM; + + mutex_lock(&aift->aift_lock); + aift->kzdev = kcalloc(ZPCI_NR_DEVICES, sizeof(struct kvm_zdev *), + GFP_KERNEL); + if (!aift->kzdev) { + rc = -ENOMEM; + goto unlock; + } + + if (!zpci_aipb) + rc = zpci_setup_aipb(nisc); + else + rc = zpci_reset_aipb(nisc); + if (rc) + goto free_zdev; + + /* Enable floating IRQs */ + if (__set_irq_noiib(SIC_IRQ_MODE_SINGLE, nisc)) { + rc = -EIO; + kvm_s390_pci_aen_exit(); + } + + goto unlock; + +free_zdev: + kfree(aift->kzdev); +unlock: + mutex_unlock(&aift->aift_lock); + return rc; +} + +/* Modify PCI: Register floating adapter interruption forwarding */ +static int kvm_zpci_set_airq(struct zpci_dev *zdev) +{ + u64 req = ZPCI_CREATE_REQ(zdev->fh, 0, ZPCI_MOD_FC_REG_INT); + struct zpci_fib fib = {}; + u8 status; + + fib.fmt0.isc = zdev->kzdev->fib.fmt0.isc; + fib.fmt0.sum = 1; /* enable summary notifications */ + fib.fmt0.noi = airq_iv_end(zdev->aibv); + fib.fmt0.aibv = virt_to_phys(zdev->aibv->vector); + fib.fmt0.aibvo = 0; + fib.fmt0.aisb = virt_to_phys(aift->sbv->vector + (zdev->aisb / 64) * 8); + fib.fmt0.aisbo = zdev->aisb & 63; + fib.gd = zdev->gisa; + + return zpci_mod_fc(req, &fib, &status) ? -EIO : 0; +} + +/* Modify PCI: Unregister floating adapter interruption forwarding */ +static int kvm_zpci_clear_airq(struct zpci_dev *zdev) +{ + u64 req = ZPCI_CREATE_REQ(zdev->fh, 0, ZPCI_MOD_FC_DEREG_INT); + struct zpci_fib fib = {}; + u8 cc, status; + + fib.gd = zdev->gisa; + + cc = zpci_mod_fc(req, &fib, &status); + if (cc == 3 || (cc == 1 && status == 24)) + /* Function already gone or IRQs already deregistered. */ + cc = 0; + + return cc ? -EIO : 0; +} + +static inline void unaccount_mem(unsigned long nr_pages) +{ + struct user_struct *user = get_uid(current_user()); + + if (user) + atomic_long_sub(nr_pages, &user->locked_vm); + if (current->mm) + atomic64_sub(nr_pages, ¤t->mm->pinned_vm); +} + +static inline int account_mem(unsigned long nr_pages) +{ + struct user_struct *user = get_uid(current_user()); + unsigned long page_limit, cur_pages, new_pages; + + page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; + + do { + cur_pages = atomic_long_read(&user->locked_vm); + new_pages = cur_pages + nr_pages; + if (new_pages > page_limit) + return -ENOMEM; + } while (atomic_long_cmpxchg(&user->locked_vm, cur_pages, + new_pages) != cur_pages); + + atomic64_add(nr_pages, ¤t->mm->pinned_vm); + + return 0; +} + +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; + struct zpci_gaite *gaite; + unsigned long hva, bit; + struct kvm *kvm; + phys_addr_t gaddr; + int rc = 0, gisc, npages, pcount = 0; + + /* + * Interrupt forwarding is only applicable if the device is already + * enabled for interpretation + */ + if (zdev->gisa == 0) + return -EINVAL; + + kvm = zdev->kzdev->kvm; + msi_vecs = min_t(unsigned int, fib->fmt0.noi, zdev->max_msi); + + /* Get the associated forwarding ISC - if invalid, return the error */ + gisc = kvm_s390_gisc_register(kvm, fib->fmt0.isc); + if (gisc < 0) + return gisc; + + /* Replace AIBV address */ + 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); + srcu_read_unlock(&kvm->srcu, idx); + if (npages < 1) { + rc = -EIO; + goto out; + } + aibv_page = pages[0]; + pcount++; + gaddr = page_to_phys(aibv_page) + (fib->fmt0.aibv & ~PAGE_MASK); + fib->fmt0.aibv = gaddr; + + /* Pin the guest AISB if one was specified */ + if (fib->fmt0.sum == 1) { + 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, + pages); + srcu_read_unlock(&kvm->srcu, idx); + if (npages < 1) { + rc = -EIO; + goto unpin1; + } + aisb_page = pages[0]; + pcount++; + } + + /* Account for pinned pages, roll back on failure */ + if (account_mem(pcount)) + 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) + 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)); + + spin_lock_irq(&aift->gait_lock); + gaite = (struct zpci_gaite *)aift->gait + (zdev->aisb * + sizeof(struct zpci_gaite)); + + /* If assist not requested, host will get all alerts */ + if (assist) + gaite->gisa = (u32)virt_to_phys(&kvm->arch.sie_page2->gisa); + else + gaite->gisa = 0; + + gaite->gisc = fib->fmt0.isc; + gaite->count++; + gaite->aisbo = fib->fmt0.aisbo; + gaite->aisb = virt_to_phys(page_address(aisb_page) + (fib->fmt0.aisb & + ~PAGE_MASK)); + 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.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; + +unlock: + mutex_unlock(&aift->aift_lock); +unpin2: + if (fib->fmt0.sum == 1) + unpin_user_page(aisb_page); +unpin1: + unpin_user_page(aibv_page); +out: + return rc; +} + +static int kvm_s390_pci_aif_disable(struct zpci_dev *zdev, bool force) +{ + struct kvm_zdev *kzdev = zdev->kzdev; + struct zpci_gaite *gaite; + struct page *vpage = NULL, *spage = NULL; + int rc, pcount = 0; + u8 isc; + + if (zdev->gisa == 0) + return -EINVAL; + + mutex_lock(&aift->aift_lock); + + /* + * If the clear fails due to an error, leave now unless we know this + * device is about to go away (force) -- In that case clear the GAITE + * regardless. + */ + rc = kvm_zpci_clear_airq(zdev); + if (rc && !force) + goto out; + + if (zdev->kzdev->fib.fmt0.aibv == 0) + goto out; + spin_lock_irq(&aift->gait_lock); + gaite = (struct zpci_gaite *)aift->gait + (zdev->aisb * + sizeof(struct zpci_gaite)); + isc = gaite->gisc; + gaite->count--; + if (gaite->count == 0) { + /* Release guest AIBV and AISB */ + vpage = phys_to_page(kzdev->fib.fmt0.aibv); + if (gaite->aisb != 0) + spage = phys_to_page(gaite->aisb); + /* Clear the GAIT entry */ + gaite->aisb = 0; + gaite->gisc = 0; + gaite->aisbo = 0; + gaite->gisa = 0; + aift->kzdev[zdev->aisb] = NULL; + /* Clear zdev info */ + airq_iv_free_bit(aift->sbv, zdev->aisb); + airq_iv_release(zdev->aibv); + zdev->aisb = 0; + zdev->aibv = NULL; + } + spin_unlock_irq(&aift->gait_lock); + kvm_s390_gisc_unregister(kzdev->kvm, isc); + kzdev->fib.fmt0.isc = 0; + kzdev->fib.fmt0.aibv = 0; + + if (vpage) { + unpin_user_page(vpage); + pcount++; + } + if (spage) { + unpin_user_page(spage); + pcount++; + } + if (pcount > 0) + unaccount_mem(pcount); +out: + mutex_unlock(&aift->aift_lock); + + return rc; +} + +static int kvm_s390_pci_dev_open(struct zpci_dev *zdev) +{ + struct kvm_zdev *kzdev; + + kzdev = kzalloc(sizeof(struct kvm_zdev), GFP_KERNEL); + if (!kzdev) + return -ENOMEM; + + kzdev->zdev = zdev; + zdev->kzdev = kzdev; + + return 0; +} + +static void kvm_s390_pci_dev_release(struct zpci_dev *zdev) +{ + struct kvm_zdev *kzdev; + + kzdev = zdev->kzdev; + WARN_ON(kzdev->zdev != zdev); + zdev->kzdev = NULL; + kfree(kzdev); +} + + +/* + * Register device with the specified KVM. If interpetation facilities are + * available, enable them and let userspace indicate whether or not they will + * be used (specify SHM bit to disable). + */ +static int kvm_s390_pci_register_kvm(void *opaque, struct kvm *kvm) +{ + struct zpci_dev *zdev = opaque; + int rc; + + if (!zdev) + return -EINVAL; + + mutex_lock(&zdev->kzdev_lock); + + if (zdev->kzdev || zdev->gisa != 0 || !kvm) { + mutex_unlock(&zdev->kzdev_lock); + return -EINVAL; + } + + kvm_get_kvm(kvm); + + mutex_lock(&kvm->lock); + + rc = kvm_s390_pci_dev_open(zdev); + if (rc) + goto err; + + /* + * If interpretation facilities aren't available, add the device to + * the kzdev list but don't enable for interpretation. + */ + if (!kvm_s390_pci_interp_allowed()) + goto out; + + /* + * If this is the first request to use an interpreted device, make the + * necessary vcpu changes + */ + if (!kvm->arch.use_zpci_interp) + kvm_s390_vcpu_pci_enable_interp(kvm); + + if (zdev_enabled(zdev)) { + rc = zpci_disable_device(zdev); + if (rc) + goto err; + } + + /* + * Store information about the identity of the kvm guest allowed to + * access this device via interpretation to be used by host CLP + */ + zdev->gisa = (u32)virt_to_phys(&kvm->arch.sie_page2->gisa); + + rc = zpci_enable_device(zdev); + if (rc) + goto clear_gisa; + + /* Re-register the IOMMU that was already created */ + rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma, + virt_to_phys(zdev->dma_table)); + if (rc) + goto clear_gisa; + +out: + zdev->kzdev->kvm = kvm; + + spin_lock(&kvm->arch.kzdev_list_lock); + list_add_tail(&zdev->kzdev->entry, &kvm->arch.kzdev_list); + spin_unlock(&kvm->arch.kzdev_list_lock); + + mutex_unlock(&kvm->lock); + mutex_unlock(&zdev->kzdev_lock); + return 0; + +clear_gisa: + zdev->gisa = 0; +err: + if (zdev->kzdev) + kvm_s390_pci_dev_release(zdev); + mutex_unlock(&kvm->lock); + mutex_unlock(&zdev->kzdev_lock); + kvm_put_kvm(kvm); + return rc; +} + +static void kvm_s390_pci_unregister_kvm(void *opaque) +{ + struct zpci_dev *zdev = opaque; + struct kvm *kvm; + + if (!zdev) + return; + + mutex_lock(&zdev->kzdev_lock); + + if (WARN_ON(!zdev->kzdev)) { + mutex_unlock(&zdev->kzdev_lock); + return; + } + + kvm = zdev->kzdev->kvm; + mutex_lock(&kvm->lock); + + /* + * A 0 gisa means interpretation was never enabled, just remove the + * device from the list. + */ + if (zdev->gisa == 0) + goto out; + + /* Forwarding must be turned off before interpretation */ + if (zdev->kzdev->fib.fmt0.aibv != 0) + kvm_s390_pci_aif_disable(zdev, true); + + /* Remove the host CLP guest designation */ + zdev->gisa = 0; + + if (zdev_enabled(zdev)) { + if (zpci_disable_device(zdev)) + goto out; + } + + if (zpci_enable_device(zdev)) + goto out; + + /* Re-register the IOMMU that was already created */ + zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma, + virt_to_phys(zdev->dma_table)); + +out: + spin_lock(&kvm->arch.kzdev_list_lock); + list_del(&zdev->kzdev->entry); + spin_unlock(&kvm->arch.kzdev_list_lock); + kvm_s390_pci_dev_release(zdev); + + mutex_unlock(&kvm->lock); + mutex_unlock(&zdev->kzdev_lock); + + kvm_put_kvm(kvm); +} + +void kvm_s390_pci_init_list(struct kvm *kvm) +{ + spin_lock_init(&kvm->arch.kzdev_list_lock); + INIT_LIST_HEAD(&kvm->arch.kzdev_list); +} + +void kvm_s390_pci_clear_list(struct kvm *kvm) +{ + /* + * This list should already be empty, either via vfio device closures + * or kvm fd cleanup. + */ + spin_lock(&kvm->arch.kzdev_list_lock); + WARN_ON_ONCE(!list_empty(&kvm->arch.kzdev_list)); + spin_unlock(&kvm->arch.kzdev_list_lock); +} + +static struct zpci_dev *get_zdev_from_kvm_by_fh(struct kvm *kvm, u32 fh) +{ + struct zpci_dev *zdev = NULL; + struct kvm_zdev *kzdev; + + spin_lock(&kvm->arch.kzdev_list_lock); + list_for_each_entry(kzdev, &kvm->arch.kzdev_list, entry) { + if (kzdev->zdev->fh == fh) { + zdev = kzdev->zdev; + break; + } + } + spin_unlock(&kvm->arch.kzdev_list_lock); + + return zdev; +} + +static int kvm_s390_pci_zpci_reg_aen(struct zpci_dev *zdev, + struct kvm_s390_zpci_op *args) +{ + struct zpci_fib fib = {}; + bool hostflag; + + fib.fmt0.aibv = args->u.reg_aen.ibv; + fib.fmt0.isc = args->u.reg_aen.isc; + fib.fmt0.noi = args->u.reg_aen.noi; + if (args->u.reg_aen.sb != 0) { + fib.fmt0.aisb = args->u.reg_aen.sb; + fib.fmt0.aisbo = args->u.reg_aen.sbo; + fib.fmt0.sum = 1; + } else { + fib.fmt0.aisb = 0; + fib.fmt0.aisbo = 0; + fib.fmt0.sum = 0; + } + + hostflag = !(args->u.reg_aen.flags & KVM_S390_ZPCIOP_REGAEN_HOST); + return kvm_s390_pci_aif_enable(zdev, &fib, hostflag); +} + +int kvm_s390_pci_zpci_op(struct kvm *kvm, struct kvm_s390_zpci_op *args) +{ + struct kvm_zdev *kzdev; + struct zpci_dev *zdev; + int r; + + zdev = get_zdev_from_kvm_by_fh(kvm, args->fh); + if (!zdev) + return -ENODEV; + + mutex_lock(&zdev->kzdev_lock); + mutex_lock(&kvm->lock); + + kzdev = zdev->kzdev; + if (!kzdev) { + r = -ENODEV; + goto out; + } + if (kzdev->kvm != kvm) { + r = -EPERM; + goto out; + } + + switch (args->op) { + case KVM_S390_ZPCIOP_REG_AEN: + /* Fail on unknown flags */ + if (args->u.reg_aen.flags & ~KVM_S390_ZPCIOP_REGAEN_HOST) { + r = -EINVAL; + break; + } + r = kvm_s390_pci_zpci_reg_aen(zdev, args); + break; + case KVM_S390_ZPCIOP_DEREG_AEN: + r = kvm_s390_pci_aif_disable(zdev, false); + break; + default: + r = -EINVAL; + } + +out: + mutex_unlock(&kvm->lock); + mutex_unlock(&zdev->kzdev_lock); + return r; +} + +int kvm_s390_pci_init(void) +{ + zpci_kvm_hook.kvm_register = kvm_s390_pci_register_kvm; + zpci_kvm_hook.kvm_unregister = kvm_s390_pci_unregister_kvm; + + if (!kvm_s390_pci_interp_allowed()) + return 0; + + aift = kzalloc(sizeof(struct zpci_aift), GFP_KERNEL); + if (!aift) + return -ENOMEM; + + spin_lock_init(&aift->gait_lock); + mutex_init(&aift->aift_lock); + + return 0; +} + +void kvm_s390_pci_exit(void) +{ + zpci_kvm_hook.kvm_register = NULL; + zpci_kvm_hook.kvm_unregister = NULL; + + if (!kvm_s390_pci_interp_allowed()) + return; + + mutex_destroy(&aift->aift_lock); + + kfree(aift); +} |