KVM: s390: pci: do initial setup for AEN interpretation

Initial setup for Adapter Event Notification Interpretation for zPCI
passthrough devices.  Specifically, allocate a structure for forwarding of
adapter events and pass the address of this structure to firmware.

Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Link: https://lore.kernel.org/r/20220606203325.110625-13-mjrosato@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>

1 files changed, 160 insertions, 0 deletions

diff --git a/arch/s390/kvm/pci.c b/arch/s390/kvm/pci.c
index e27191ea27c4..d566551d3018 100644
--- a/arch/s390/kvm/pci.c
+++ b/arch/s390/kvm/pci.c
@@ -9,8 +9,149 @@
 
 #include <linux/kvm_host.h>
 #include <linux/pci.h>
+#include <asm/pci.h>
+#include <asm/pci_insn.h>
 #include "pci.h"
 
+struct zpci_aift *aift;
+
+static inline int __set_irq_noiib(u16 ctl, u8 isc)
+{
+	union zpci_sic_iib iib = {{0}};
+
+	return zpci_set_irq_ctrl(ctl, isc, &iib);
+}
+
+void kvm_s390_pci_aen_exit(void)
+{
+	unsigned long flags;
+	struct kvm_zdev **gait_kzdev;
+
+	lockdep_assert_held(&aift->aift_lock);
+
+	/*
+	 * Contents of the aipb remain registered for the life of the host
+	 * kernel, the information preserved in zpci_aipb and zpci_aif_sbv
+	 * in case we insert the KVM module again later.  Clear the AIFT
+	 * information and free anything not registered with underlying
+	 * firmware.
+	 */
+	spin_lock_irqsave(&aift->gait_lock, flags);
+	gait_kzdev = aift->kzdev;
+	aift->gait = NULL;
+	aift->sbv = NULL;
+	aift->kzdev = NULL;
+	spin_unlock_irqrestore(&aift->gait_lock, flags);
+
+	kfree(gait_kzdev);
+}
+
+static int zpci_setup_aipb(u8 nisc)
+{
+	struct page *page;
+	int size, rc;
+
+	zpci_aipb = kzalloc(sizeof(union zpci_sic_iib), GFP_KERNEL);
+	if (!zpci_aipb)
+		return -ENOMEM;
+
+	aift->sbv = airq_iv_create(ZPCI_NR_DEVICES, AIRQ_IV_ALLOC, 0);
+	if (!aift->sbv) {
+		rc = -ENOMEM;
+		goto free_aipb;
+	}
+	zpci_aif_sbv = aift->sbv;
+	size = get_order(PAGE_ALIGN(ZPCI_NR_DEVICES *
+						sizeof(struct zpci_gaite)));
+	page = alloc_pages(GFP_KERNEL | __GFP_ZERO, size);
+	if (!page) {
+		rc = -ENOMEM;
+		goto free_sbv;
+	}
+	aift->gait = (struct zpci_gaite *)page_to_phys(page);
+
+	zpci_aipb->aipb.faisb = virt_to_phys(aift->sbv->vector);
+	zpci_aipb->aipb.gait = virt_to_phys(aift->gait);
+	zpci_aipb->aipb.afi = nisc;
+	zpci_aipb->aipb.faal = ZPCI_NR_DEVICES;
+
+	/* Setup Adapter Event Notification Interpretation */
+	if (zpci_set_irq_ctrl(SIC_SET_AENI_CONTROLS, 0, zpci_aipb)) {
+		rc = -EIO;
+		goto free_gait;
+	}
+
+	return 0;
+
+free_gait:
+	free_pages((unsigned long)aift->gait, size);
+free_sbv:
+	airq_iv_release(aift->sbv);
+	zpci_aif_sbv = NULL;
+free_aipb:
+	kfree(zpci_aipb);
+	zpci_aipb = NULL;
+
+	return rc;
+}
+
+static int zpci_reset_aipb(u8 nisc)
+{
+	/*
+	 * AEN registration can only happen once per system boot.  If
+	 * an aipb already exists then AEN was already registered and
+	 * we can re-use the aipb contents.  This can only happen if
+	 * the KVM module was removed and re-inserted.  However, we must
+	 * ensure that the same forwarding ISC is used as this is assigned
+	 * during KVM module load.
+	 */
+	if (zpci_aipb->aipb.afi != nisc)
+		return -EINVAL;
+
+	aift->sbv = zpci_aif_sbv;
+	aift->gait = (struct zpci_gaite *)zpci_aipb->aipb.gait;
+
+	return 0;
+}
+
+int kvm_s390_pci_aen_init(u8 nisc)
+{
+	int rc = 0;
+
+	/* If already enabled for AEN, bail out now */
+	if (aift->gait || aift->sbv)
+		return -EPERM;
+
+	mutex_lock(&aift->aift_lock);
+	aift->kzdev = kcalloc(ZPCI_NR_DEVICES, sizeof(struct kvm_zdev),
+			      GFP_KERNEL);
+	if (!aift->kzdev) {
+		rc = -ENOMEM;
+		goto unlock;
+	}
+
+	if (!zpci_aipb)
+		rc = zpci_setup_aipb(nisc);
+	else
+		rc = zpci_reset_aipb(nisc);
+	if (rc)
+		goto free_zdev;
+
+	/* Enable floating IRQs */
+	if (__set_irq_noiib(SIC_IRQ_MODE_SINGLE, nisc)) {
+		rc = -EIO;
+		kvm_s390_pci_aen_exit();
+	}
+
+	goto unlock;
+
+free_zdev:
+	kfree(aift->kzdev);
+unlock:
+	mutex_unlock(&aift->aift_lock);
+	return rc;
+}
+
 static int kvm_s390_pci_dev_open(struct zpci_dev *zdev)
 {
 	struct kvm_zdev *kzdev;
@@ -34,3 +175,22 @@ static void kvm_s390_pci_dev_release(struct zpci_dev *zdev)
 	zdev->kzdev = NULL;
 	kfree(kzdev);
 }
+
+int kvm_s390_pci_init(void)
+{
+	aift = kzalloc(sizeof(struct zpci_aift), GFP_KERNEL);
+	if (!aift)
+		return -ENOMEM;
+
+	spin_lock_init(&aift->gait_lock);
+	mutex_init(&aift->aift_lock);
+
+	return 0;
+}
+
+void kvm_s390_pci_exit(void)
+{
+	mutex_destroy(&aift->aift_lock);
+
+	kfree(aift);
+}