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Diffstat (limited to 'arch/s390/kvm/pci.c')
-rw-r--r--arch/s390/kvm/pci.c690
1 files changed, 690 insertions, 0 deletions
diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
new file mode 100644
index 000000000000..4946fb7757d6
--- /dev/null
+++ b/arch/s390/kvm/pci.c
@@ -0,0 +1,690 @@
+// 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, 0);
+ 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_phys(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, &current->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, &current->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] = 0;
+ /* 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).
+ */
+int kvm_s390_pci_register_kvm(struct zpci_dev *zdev, struct kvm *kvm)
+{
+ 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;
+}
+EXPORT_SYMBOL_GPL(kvm_s390_pci_register_kvm);
+
+void kvm_s390_pci_unregister_kvm(struct zpci_dev *zdev)
+{
+ 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);
+}
+EXPORT_SYMBOL_GPL(kvm_s390_pci_unregister_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)
+{
+ 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)
+{
+ mutex_destroy(&aift->aift_lock);
+
+ kfree(aift);
+}