Re: [PATCH 21/32] KVM: s390: pci: provide routines for enabling/disabling interrupt forwarding

Pierre Morel
2021-12-14T09:25:48Z

On 12/7/21 21:57, Matthew Rosato wrote:
> 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);
> +

No need for extern in the prototype definition.

> 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;

no blanc needed after cast

> + fib.fmt0.aibvo = 0;
> + fib.fmt0.aisb = (unsigned long) aift.sbv->vector + (zdev->aisb/64) * 8;

same here and blancs needed arround /

> + 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 *
no blanc after cast

> + 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;

no blanc after cast and blanc arround / and *

> + 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 *
dito cast
> + 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)
>

--
Pierre Morel
IBM Lab Boeblingen