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.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>

arch/s390/include/asm/pci_insn.h

@@ -101,6 +101,7 @@ struct zpci_fib {
 /* Set Interruption Controls Operation Controls  */
 #define	SIC_IRQ_MODE_ALL		0
 #define	SIC_IRQ_MODE_SINGLE		1
+#define	SIC_SET_AENI_CONTROLS		2
 #define	SIC_IRQ_MODE_DIRECT		4
 #define	SIC_IRQ_MODE_D_ALL		16
 #define	SIC_IRQ_MODE_D_SINGLE		17
@@ -127,9 +128,20 @@ struct zpci_cdiib {
 	u64 : 64;
 } __packed __aligned(8);
 
+/* adapter interruption parameters block */
+struct zpci_aipb {
+	u64 faisb;
+	u64 gait;
+	u16 : 13;
+	u16 afi : 3;
+	u32 : 32;
+	u16 faal;
+} __packed __aligned(8);
+
 union zpci_sic_iib {
 	struct zpci_diib diib;
 	struct zpci_cdiib cdiib;
+	struct zpci_aipb aipb;
 };
 
 DECLARE_STATIC_KEY_FALSE(have_mio);

arch/s390/kvm/interrupt.c

@@ -32,6 +32,7 @@
 #include "kvm-s390.h"
 #include "gaccess.h"
 #include "trace-s390.h"
+#include "pci.h"
 
 #define PFAULT_INIT 0x0600
 #define PFAULT_DONE 0x0680
@@ -3276,8 +3277,16 @@ static struct airq_struct gib_alert_irq = {
 
 void kvm_s390_gib_destroy(void)
 {
+	struct zpci_aift *aift;
+
 	if (!gib)
 		return;
+	aift = kvm_s390_pci_get_aift();
+	if (aift) {
+		mutex_lock(&aift->lock);
+		kvm_s390_pci_aen_exit();
+		mutex_unlock(&aift->lock);
+	}
 	chsc_sgib(0);
 	unregister_adapter_interrupt(&gib_alert_irq);
 	free_page((unsigned long)gib);
@@ -3315,6 +3324,14 @@ int kvm_s390_gib_init(u8 nisc)
 		goto out_unreg_gal;
 	}
 
+	if (IS_ENABLED(CONFIG_PCI) && sclp.has_aeni) {
+		if (kvm_s390_pci_aen_init(nisc)) {
+			pr_err("Initializing AEN for PCI failed\n");
+			rc = -EIO;
+			goto out_unreg_gal;
+		}
+	}
+
 	KVM_EVENT(3, "gib 0x%pK (nisc=%d) initialized", gib, gib->nisc);
 	goto out;
 

arch/s390/kvm/kvm-s390.c

@@ -48,6 +48,7 @@
 #include <asm/fpu/api.h>
 #include "kvm-s390.h"
 #include "gaccess.h"
+#include "pci.h"
 
 #define CREATE_TRACE_POINTS
 #include "trace.h"
@@ -503,6 +504,8 @@ int kvm_arch_init(void *opaque)
 		goto out;
 	}
 
+	kvm_s390_pci_init();
+
 	rc = kvm_s390_gib_init(GAL_ISC);
 	if (rc)
 		goto out;

arch/s390/kvm/pci.c

@@ -10,6 +10,113 @@
 #include <linux/kvm_host.h>
 #include <linux/pci.h>
 #include <asm/kvm_pci.h>
+#include "pci.h"
+
+static 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);
+}
+
+struct zpci_aift *kvm_s390_pci_get_aift(void)
+{
+	return &aift;
+}
+
+/* Caller must hold the aift lock before calling this function */
+void kvm_s390_pci_aen_exit(void)
+{
+	struct zpci_gaite *gait;
+	unsigned long flags;
+	struct airq_iv *sbv;
+	struct kvm_zdev **gait_kzdev;
+	int size;
+
+	/* Clear the GAIT and forwarding summary vector */
+	__set_irq_noiib(SIC_SET_AENI_CONTROLS, 0);
+
+	spin_lock_irqsave(&aift.gait_lock, flags);
+	gait = aift.gait;
+	sbv = aift.sbv;
+	gait_kzdev = aift.kzdev;
+	aift.gait = 0;
+	aift.sbv = 0;
+	aift.kzdev = 0;
+	spin_unlock_irqrestore(&aift.gait_lock, flags);
+
+	if (sbv)
+		airq_iv_release(sbv);
+	size = get_order(PAGE_ALIGN(ZPCI_NR_DEVICES *
+				    sizeof(struct zpci_gaite)));
+	free_pages((unsigned long)gait, size);
+	kfree(gait_kzdev);
+}
+
+int kvm_s390_pci_aen_init(u8 nisc)
+{
+	union zpci_sic_iib iib = {{0}};
+	struct page *page;
+	int rc = 0, size;
+
+	/* If already enabled for AEN, bail out now */
+	if (aift.gait || aift.sbv)
+		return -EPERM;
+
+	mutex_lock(&aift.lock);
+	aift.kzdev = kcalloc(ZPCI_NR_DEVICES, sizeof(struct kvm_zdev),
+			     GFP_KERNEL);
+	if (!aift.kzdev) {
+		rc = -ENOMEM;
+		goto unlock;
+	}
+	aift.sbv = airq_iv_create(ZPCI_NR_DEVICES, AIRQ_IV_ALLOC, 0);
+	if (!aift.sbv) {
+		rc = -ENOMEM;
+		goto free_zdev;
+	}
+	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);
+
+	iib.aipb.faisb = (u64)aift.sbv->vector;
+	iib.aipb.gait = (u64)aift.gait;
+	iib.aipb.afi = nisc;
+	iib.aipb.faal = ZPCI_NR_DEVICES;
+
+	/* Setup Adapter Event Notification Interpretation */
+	if (zpci_set_irq_ctrl(SIC_SET_AENI_CONTROLS, 0, &iib)) {
+		rc = -EIO;
+		goto free_gait;
+	}
+
+	/* Enable floating IRQs */
+	if (__set_irq_noiib(SIC_IRQ_MODE_SINGLE, nisc)) {
+		rc = -EIO;
+		kvm_s390_pci_aen_exit();
+	}
+
+	goto unlock;
+
+free_gait:
+	size = get_order(PAGE_ALIGN(ZPCI_NR_DEVICES *
+				    sizeof(struct zpci_gaite)));
+	free_pages((unsigned long)aift.gait, size);
+free_sbv:
+	airq_iv_release(aift.sbv);
+free_zdev:
+	kfree(aift.kzdev);
+unlock:
+	mutex_unlock(&aift.lock);
+	return rc;
+}
 
 int kvm_s390_pci_dev_open(struct zpci_dev *zdev)
 {
@@ -55,3 +162,9 @@ int kvm_s390_pci_attach_kvm(struct zpci_dev *zdev, struct kvm *kvm)
 	return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_s390_pci_attach_kvm);
+
+void kvm_s390_pci_init(void)
+{
+	spin_lock_init(&aift.gait_lock);
+	mutex_init(&aift.lock);
+}

arch/s390/kvm/pci.h

@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * s390 kvm PCI passthrough support
+ *
+ * Copyright IBM Corp. 2021
+ *
+ *    Author(s): Matthew Rosato <mjrosato@linux.ibm.com>
+ */
+
+#ifndef __KVM_S390_PCI_H
+#define __KVM_S390_PCI_H
+
+#include <linux/pci.h>
+#include <linux/mutex.h>
+#include <asm/airq.h>
+#include <asm/kvm_pci.h>
+
+struct zpci_gaite {
+	unsigned int gisa;
+	u8 gisc;
+	u8 count;
+	u8 reserved;
+	u8 aisbo;
+	unsigned long aisb;
+};
+
+struct zpci_aift {
+	struct zpci_gaite *gait;
+	struct airq_iv *sbv;
+	struct kvm_zdev **kzdev;
+	spinlock_t gait_lock; /* Protects the gait, used during AEN forward */
+	struct mutex lock; /* Protects the other structures in aift */
+};
+
+struct zpci_aift *kvm_s390_pci_get_aift(void);
+
+int kvm_s390_pci_aen_init(u8 nisc);
+void kvm_s390_pci_aen_exit(void);
+
+void kvm_s390_pci_init(void);
+
+#endif /* __KVM_S390_PCI_H */