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|
// 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;
u8 status;
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), &status);
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;
u8 status;
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), &status);
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);
}
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