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

Matthew Rosato
2021-12-07T21:00:14Z

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