KVM: s390: pci: provide routines for enabling/disabling interrupt forwarding

These routines will be wired into a kvm ioctl in order to respond to
requests to enable / disable a device for Adapter Event Notifications /
Adapter Interuption Forwarding.

Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Acked-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Link: https://lore.kernel.org/r/20220606203325.110625-16-mjrosato@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
This commit is contained in:
Matthew Rosato 2022-06-06 16:33:19 -04:00 committed by Christian Borntraeger
parent 3f4bbb4342
commit 3c5a1b6f0a
4 changed files with 251 additions and 1 deletions

View File

@ -11,6 +11,7 @@
#include <linux/pci.h>
#include <asm/pci.h>
#include <asm/pci_insn.h>
#include <asm/pci_io.h>
#include "pci.h"
struct zpci_aift *aift;
@ -152,6 +153,252 @@ unlock:
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;

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@ -20,6 +20,7 @@
struct kvm_zdev {
struct zpci_dev *zdev;
struct kvm *kvm;
struct zpci_fib fib;
};
struct zpci_gaite {

View File

@ -92,6 +92,7 @@ u8 zpci_mod_fc(u64 req, struct zpci_fib *fib, u8 *status)
return cc;
}
EXPORT_SYMBOL_GPL(zpci_mod_fc);
/* Refresh PCI Translations */
static inline u8 __rpcit(u64 fn, u64 addr, u64 range, u8 *status)

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@ -24,7 +24,8 @@ struct user_struct {
kuid_t uid;
#if defined(CONFIG_PERF_EVENTS) || defined(CONFIG_BPF_SYSCALL) || \
defined(CONFIG_NET) || defined(CONFIG_IO_URING)
defined(CONFIG_NET) || defined(CONFIG_IO_URING) || \
defined(CONFIG_VFIO_PCI_ZDEV_KVM)
atomic_long_t locked_vm;
#endif
#ifdef CONFIG_WATCH_QUEUE