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    Subject[PATCH v6 14/21] KVM: s390: pci: provide routines for enabling/disabling interrupt forwarding
    Date
    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.

    Acked-by: Niklas Schnelle <schnelle@linux.ibm.com>
    Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
    ---
    arch/s390/kvm/pci.c | 247 +++++++++++++++++++++++++++++++++++++++
    arch/s390/kvm/pci.h | 1 +
    arch/s390/pci/pci_insn.c | 1 +
    3 files changed, 249 insertions(+)

    diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
    index 6e6636c20fa2..72a9c6bfae86 100644
    --- a/arch/s390/kvm/pci.c
    +++ b/arch/s390/kvm/pci.c
    @@ -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;
    @@ -151,6 +152,252 @@ int kvm_s390_pci_aen_init(u8 nisc)
    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;
    +}
    +
    int kvm_s390_pci_dev_open(struct zpci_dev *zdev)
    {
    struct kvm_zdev *kzdev;
    diff --git a/arch/s390/kvm/pci.h b/arch/s390/kvm/pci.h
    index d97cc99ebd46..f567c3189a40 100644
    --- a/arch/s390/kvm/pci.h
    +++ b/arch/s390/kvm/pci.h
    @@ -20,6 +20,7 @@
    struct kvm_zdev {
    struct zpci_dev *zdev;
    struct kvm *kvm;
    + struct zpci_fib fib;
    };

    struct zpci_gaite {
    diff --git a/arch/s390/pci/pci_insn.c b/arch/s390/pci/pci_insn.c
    index 4c6967b73932..cd9fb186a6be 100644
    --- a/arch/s390/pci/pci_insn.c
    +++ b/arch/s390/pci/pci_insn.c
    @@ -60,6 +60,7 @@ 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)
    --
    2.27.0
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      Last update: 2022-04-26 22:12    [W:4.081 / U:0.268 seconds]
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