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    Subject[PATCH 21/32] KVM: s390: pci: provide routines for enabling/disabling interrupt forwarding
    Date
    These routines will be wired into the vfio_pci_zdev ioctl handlers to
    respond to requests to enable / disable a device for Adapter Event
    Notifications / Adapter Interuption Forwarding.

    Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
    ---
    arch/s390/include/asm/kvm_pci.h | 7 ++
    arch/s390/kvm/pci.c | 199 ++++++++++++++++++++++++++++++++
    arch/s390/pci/pci_insn.c | 1 +
    3 files changed, 207 insertions(+)

    diff --git a/arch/s390/include/asm/kvm_pci.h b/arch/s390/include/asm/kvm_pci.h
    index 5d6283acb54c..54a0afdbe7d0 100644
    --- a/arch/s390/include/asm/kvm_pci.h
    +++ b/arch/s390/include/asm/kvm_pci.h
    @@ -16,16 +16,23 @@
    #include <linux/kvm_host.h>
    #include <linux/kvm.h>
    #include <linux/pci.h>
    +#include <asm/pci_insn.h>

    struct kvm_zdev {
    struct zpci_dev *zdev;
    struct kvm *kvm;
    + struct zpci_fib fib;
    };

    extern int kvm_s390_pci_dev_open(struct zpci_dev *zdev);
    extern void kvm_s390_pci_dev_release(struct zpci_dev *zdev);
    extern int kvm_s390_pci_attach_kvm(struct zpci_dev *zdev, struct kvm *kvm);

    +extern int kvm_s390_pci_aif_probe(struct zpci_dev *zdev);
    +extern int kvm_s390_pci_aif_enable(struct zpci_dev *zdev, struct zpci_fib *fib,
    + bool assist);
    +extern int kvm_s390_pci_aif_disable(struct zpci_dev *zdev);
    +
    extern int kvm_s390_pci_interp_probe(struct zpci_dev *zdev);
    extern int kvm_s390_pci_interp_enable(struct zpci_dev *zdev);
    extern int kvm_s390_pci_interp_disable(struct zpci_dev *zdev);
    diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
    index 57cbe3827ea6..3a29398dd53b 100644
    --- a/arch/s390/kvm/pci.c
    +++ b/arch/s390/kvm/pci.c
    @@ -10,6 +10,8 @@
    #include <linux/kvm_host.h>
    #include <linux/pci.h>
    #include <asm/kvm_pci.h>
    +#include <asm/pci.h>
    +#include <asm/pci_insn.h>
    #include <asm/sclp.h>
    #include "pci.h"
    #include "kvm-s390.h"
    @@ -120,6 +122,199 @@ 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 = {0};
    + 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 = (unsigned long) zdev->aibv->vector;
    + fib.fmt0.aibvo = 0;
    + fib.fmt0.aisb = (unsigned long) aift.sbv->vector + (zdev->aisb/64) * 8;
    + fib.fmt0.aisbo = zdev->aisb & 63;
    + fib.gd = zdev->gd;
    +
    + 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 = {0};
    + u8 cc, status;
    +
    + fib.gd = zdev->gd;
    +
    + 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;
    +}
    +
    +int kvm_s390_pci_aif_probe(struct zpci_dev *zdev)
    +{
    + if (!(sclp.has_aeni && test_facility(71)))
    + return -EINVAL;
    +
    + return 0;
    +}
    +EXPORT_SYMBOL_GPL(kvm_s390_pci_aif_probe);
    +
    +int kvm_s390_pci_aif_enable(struct zpci_dev *zdev, struct zpci_fib *fib,
    + bool assist)
    +{
    + struct page *aibv_page, *aisb_page = NULL;
    + unsigned int msi_vecs, idx;
    + struct zpci_gaite *gaite;
    + unsigned long bit;
    + struct kvm *kvm;
    + void *gaddr;
    + int rc = 0;
    +
    + /*
    + * Interrupt forwarding is only applicable if the device is already
    + * enabled for interpretation
    + */
    + if (zdev->gd == 0)
    + return -EINVAL;
    +
    + kvm = zdev->kzdev->kvm;
    + msi_vecs = min_t(unsigned int, fib->fmt0.noi, zdev->max_msi);
    +
    + /* Replace AIBV address */
    + idx = srcu_read_lock(&kvm->srcu);
    + aibv_page = gfn_to_page(kvm, gpa_to_gfn((gpa_t)fib->fmt0.aibv));
    + srcu_read_unlock(&kvm->srcu, idx);
    + if (is_error_page(aibv_page)) {
    + rc = -EIO;
    + goto out;
    + }
    + gaddr = page_to_virt(aibv_page) + (fib->fmt0.aibv & ~PAGE_MASK);
    + fib->fmt0.aibv = (u64)gaddr;
    +
    + /* Pin the guest AISB if one was specified */
    + if (fib->fmt0.sum == 1) {
    + idx = srcu_read_lock(&kvm->srcu);
    + aisb_page = gfn_to_page(kvm, gpa_to_gfn((gpa_t)fib->fmt0.aisb));
    + srcu_read_unlock(&kvm->srcu, idx);
    + if (is_error_page(aisb_page)) {
    + rc = -EIO;
    + goto unpin1;
    + }
    + }
    +
    + /* AISB must be allocated before we can fill in GAITE */
    + mutex_lock(&aift.lock);
    + bit = airq_iv_alloc_bit(aift.sbv);
    + if (bit == -1UL)
    + goto unpin2;
    + zdev->aisb = bit;
    + zdev->aibv = airq_iv_create(msi_vecs, AIRQ_IV_DATA |
    + AIRQ_IV_BITLOCK |
    + AIRQ_IV_GUESTVEC,
    + (unsigned long *)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)(u64)&kvm->arch.sie_page2->gisa;
    + else
    + gaite->gisa = 0;
    +
    + gaite->gisc = fib->fmt0.isc;
    + gaite->count++;
    + gaite->aisbo = fib->fmt0.aisbo;
    + gaite->aisb = (u64)(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 = (unsigned long) aift.sbv->vector + (zdev->aisb/64)*8;
    + fib->fmt0.isc = kvm_s390_gisc_register(kvm, gaite->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.lock);
    +
    + /* Issue the clp to setup the irq now */
    + rc = kvm_zpci_set_airq(zdev);
    + return rc;
    +
    +unpin2:
    + mutex_unlock(&aift.lock);
    + if (fib->fmt0.sum == 1) {
    + gaddr = page_to_virt(aisb_page);
    + kvm_release_pfn_dirty((u64)gaddr >> PAGE_SHIFT);
    + }
    +unpin1:
    + kvm_release_pfn_dirty(fib->fmt0.aibv >> PAGE_SHIFT);
    +out:
    + return rc;
    +}
    +EXPORT_SYMBOL_GPL(kvm_s390_pci_aif_enable);
    +
    +int kvm_s390_pci_aif_disable(struct zpci_dev *zdev)
    +{
    + struct kvm_zdev *kzdev = zdev->kzdev;
    + struct zpci_gaite *gaite;
    + int rc;
    + u8 isc;
    +
    + if (zdev->gd == 0)
    + return -EINVAL;
    +
    + /* Even if the clear fails due to an error, clear the GAITE */
    + rc = kvm_zpci_clear_airq(zdev);
    +
    + mutex_lock(&aift.lock);
    + 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 */
    + kvm_release_pfn_dirty(kzdev->fib.fmt0.aibv >> PAGE_SHIFT);
    + if (gaite->aisb != 0)
    + kvm_release_pfn_dirty(gaite->aisb >> PAGE_SHIFT);
    + /* 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;
    +out:
    + mutex_unlock(&aift.lock);
    +
    + return rc;
    +}
    +EXPORT_SYMBOL_GPL(kvm_s390_pci_aif_disable);
    +
    int kvm_s390_pci_interp_probe(struct zpci_dev *zdev)
    {
    if (!(sclp.has_zpci_interp && test_facility(69)))
    @@ -188,6 +383,10 @@ int kvm_s390_pci_interp_disable(struct zpci_dev *zdev)
    if (zdev->gd == 0)
    return -EINVAL;

    + /* Forwarding must be turned off before interpretation */
    + if (zdev->kzdev->fib.fmt0.aibv != 0)
    + kvm_s390_pci_aif_disable(zdev);
    +
    /* Remove the host CLP guest designation */
    zdev->gd = 0;

    diff --git a/arch/s390/pci/pci_insn.c b/arch/s390/pci/pci_insn.c
    index 0d1ab268ec24..b57d3f594113 100644
    --- a/arch/s390/pci/pci_insn.c
    +++ b/arch/s390/pci/pci_insn.c
    @@ -59,6 +59,7 @@ 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: 2021-12-07 22:00    [W:4.065 / U:0.272 seconds]
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