[Qemu-devel] [PATCH v14 2/5] intc/gic: Extract some reusable vGIC code

[Pavel Fedin]

Some functions previously used only by vGICv2 are useful also for vGICv3
implementation. Untie them from GICState and make accessible from within
other modules:
- kvm_arm_gic_set_irq()
- kvm_gic_supports_attr() - moved to common code and renamed to
  kvm_device_check_attr()
- kvm_gic_access() - turned into GIC-independent kvm_device_access().
  Data pointer changed to void * because some GICv3 registers are
  64-bit wide

Some of these changes are not used right now, but they will be helpful for
implementing live migration.

Actually kvm_dist_get() and kvm_dist_put() could also be made reusable, but
they would require two extra parameters (s->dev_fd and s->num_cpu) as well as
lots of typecasts of 's' to DeviceState * and back to GICState *. This makes
the code very ugly so i decided to stop at this point. I tried also an
approach with making a base class for all possible GICs, but it would contain
only three variables (dev_fd, cpu_num and irq_num), and accessing them through
the rest of the code would be again tedious (either ugly casts or qemu-style
separate object pointer). So i disliked it too.

Signed-off-by: Pavel Fedin <address@hidden>
Tested-by: Ashok kumar <address@hidden>
---
 hw/intc/arm_gic_kvm.c | 98 +++++++++++++++++----------------------------------
 hw/intc/vgic_common.h | 35 ++++++++++++++++++
 include/sysemu/kvm.h  | 26 ++++++++++++++
 kvm-all.c             | 34 ++++++++++++++++++
 4 files changed, 128 insertions(+), 65 deletions(-)
 create mode 100644 hw/intc/vgic_common.h

diff --git a/hw/intc/arm_gic_kvm.c b/hw/intc/arm_gic_kvm.c
index e5d0f67..e8b2386 100644
--- a/hw/intc/arm_gic_kvm.c
+++ b/hw/intc/arm_gic_kvm.c
@@ -23,6 +23,7 @@
 #include "sysemu/kvm.h"
 #include "kvm_arm.h"
 #include "gic_internal.h"
+#include "vgic_common.h"
 
 //#define DEBUG_GIC_KVM
 
@@ -52,7 +53,7 @@ typedef struct KVMARMGICClass {
     void (*parent_reset)(DeviceState *dev);
 } KVMARMGICClass;
 
-static void kvm_arm_gic_set_irq(void *opaque, int irq, int level)
+void kvm_arm_gic_set_irq(uint32_t num_irq, int irq, int level)
 {
     /* Meaning of the 'irq' parameter:
      *  [0..N-1] : external interrupts
@@ -63,10 +64,9 @@ static void kvm_arm_gic_set_irq(void *opaque, int irq, int 
level)
      * has separate fields in the irq number for type,
      * CPU number and interrupt number.
      */
-    GICState *s = (GICState *)opaque;
     int kvm_irq, irqtype, cpu;
 
-    if (irq < (s->num_irq - GIC_INTERNAL)) {
+    if (irq < (num_irq - GIC_INTERNAL)) {
         /* External interrupt. The kernel numbers these like the GIC
          * hardware, with external interrupt IDs starting after the
          * internal ones.
@@ -77,7 +77,7 @@ static void kvm_arm_gic_set_irq(void *opaque, int irq, int 
level)
     } else {
         /* Internal interrupt: decode into (cpu, interrupt id) */
         irqtype = KVM_ARM_IRQ_TYPE_PPI;
-        irq -= (s->num_irq - GIC_INTERNAL);
+        irq -= (num_irq - GIC_INTERNAL);
         cpu = irq / GIC_INTERNAL;
         irq %= GIC_INTERNAL;
     }
@@ -87,69 +87,36 @@ static void kvm_arm_gic_set_irq(void *opaque, int irq, int 
level)
     kvm_set_irq(kvm_state, kvm_irq, !!level);
 }
 
-static bool kvm_arm_gic_can_save_restore(GICState *s)
-{
-    return s->dev_fd >= 0;
-}
-
-static bool kvm_gic_supports_attr(GICState *s, int group, int attrnum)
+static void kvm_arm_gicv2_set_irq(void *opaque, int irq, int level)
 {
-    struct kvm_device_attr attr = {
-        .group = group,
-        .attr = attrnum,
-        .flags = 0,
-    };
-
-    if (s->dev_fd == -1) {
-        return false;
-    }
+    GICState *s = (GICState *)opaque;
 
-    return kvm_device_ioctl(s->dev_fd, KVM_HAS_DEVICE_ATTR, &attr) == 0;
+    kvm_arm_gic_set_irq(s->num_irq, irq, level);
 }
 
-static void kvm_gic_access(GICState *s, int group, int offset,
-                                   int cpu, uint32_t *val, bool write)
+static bool kvm_arm_gic_can_save_restore(GICState *s)
 {
-    struct kvm_device_attr attr;
-    int type;
-    int err;
-
-    cpu = cpu & 0xff;
-
-    attr.flags = 0;
-    attr.group = group;
-    attr.attr = (((uint64_t)cpu << KVM_DEV_ARM_VGIC_CPUID_SHIFT) &
-                 KVM_DEV_ARM_VGIC_CPUID_MASK) |
-                (((uint64_t)offset << KVM_DEV_ARM_VGIC_OFFSET_SHIFT) &
-                 KVM_DEV_ARM_VGIC_OFFSET_MASK);
-    attr.addr = (uintptr_t)val;
-
-    if (write) {
-        type = KVM_SET_DEVICE_ATTR;
-    } else {
-        type = KVM_GET_DEVICE_ATTR;
-    }
-
-    err = kvm_device_ioctl(s->dev_fd, type, &attr);
-    if (err < 0) {
-        fprintf(stderr, "KVM_{SET/GET}_DEVICE_ATTR failed: %s\n",
-                strerror(-err));
-        abort();
-    }
+    return s->dev_fd >= 0;
 }
 
+#define KVM_VGIC_ATTR(offset, cpu) \
+    ((((uint64_t)(cpu) << KVM_DEV_ARM_VGIC_CPUID_SHIFT) & \
+      KVM_DEV_ARM_VGIC_CPUID_MASK) | \
+     (((uint64_t)(offset) << KVM_DEV_ARM_VGIC_OFFSET_SHIFT) & \
+      KVM_DEV_ARM_VGIC_OFFSET_MASK))
+
 static void kvm_gicd_access(GICState *s, int offset, int cpu,
                             uint32_t *val, bool write)
 {
-    kvm_gic_access(s, KVM_DEV_ARM_VGIC_GRP_DIST_REGS,
-                   offset, cpu, val, write);
+    kvm_device_access(s->dev_fd, KVM_DEV_ARM_VGIC_GRP_DIST_REGS,
+                      KVM_VGIC_ATTR(offset, cpu), val, write);
 }
 
 static void kvm_gicc_access(GICState *s, int offset, int cpu,
                             uint32_t *val, bool write)
 {
-    kvm_gic_access(s, KVM_DEV_ARM_VGIC_GRP_CPU_REGS,
-                   offset, cpu, val, write);
+    kvm_device_access(s->dev_fd, KVM_DEV_ARM_VGIC_GRP_CPU_REGS,
+                      KVM_VGIC_ATTR(offset, cpu), val, write);
 }
 
 #define for_each_irq_reg(_ctr, _max_irq, _field_width) \
@@ -559,7 +526,7 @@ static void kvm_arm_gic_realize(DeviceState *dev, Error 
**errp)
         return;
     }
 
-    gic_init_irqs_and_mmio(s, kvm_arm_gic_set_irq, NULL);
+    gic_init_irqs_and_mmio(s, kvm_arm_gicv2_set_irq, NULL);
 
     for (i = 0; i < s->num_irq - GIC_INTERNAL; i++) {
         qemu_irq irq = qdev_get_gpio_in(dev, i);
@@ -571,23 +538,24 @@ static void kvm_arm_gic_realize(DeviceState *dev, Error 
**errp)
     ret = kvm_create_device(kvm_state, KVM_DEV_TYPE_ARM_VGIC_V2, false);
     if (ret >= 0) {
         s->dev_fd = ret;
+
+        /* Newstyle API is used, we may have attributes */
+        if (kvm_device_check_attr(s->dev_fd, KVM_DEV_ARM_VGIC_GRP_NR_IRQS, 0)) 
{
+            uint32_t numirqs = s->num_irq;
+            kvm_device_access(s->dev_fd, KVM_DEV_ARM_VGIC_GRP_NR_IRQS, 0,
+                              &numirqs, true);
+        }
+        /* Tell the kernel to complete VGIC initialization now */
+        if (kvm_device_check_attr(s->dev_fd, KVM_DEV_ARM_VGIC_GRP_CTRL,
+                                  KVM_DEV_ARM_VGIC_CTRL_INIT)) {
+            kvm_device_access(s->dev_fd, KVM_DEV_ARM_VGIC_GRP_CTRL,
+                              KVM_DEV_ARM_VGIC_CTRL_INIT, NULL, true);
+        }
     } else if (ret != -ENODEV && ret != -ENOTSUP) {
         error_setg_errno(errp, -ret, "error creating in-kernel VGIC");
         return;
     }
 
-    if (kvm_gic_supports_attr(s, KVM_DEV_ARM_VGIC_GRP_NR_IRQS, 0)) {
-        uint32_t numirqs = s->num_irq;
-        kvm_gic_access(s, KVM_DEV_ARM_VGIC_GRP_NR_IRQS, 0, 0, &numirqs, 1);
-    }
-
-    /* Tell the kernel to complete VGIC initialization now */
-    if (kvm_gic_supports_attr(s, KVM_DEV_ARM_VGIC_GRP_CTRL,
-                              KVM_DEV_ARM_VGIC_CTRL_INIT)) {
-        kvm_gic_access(s, KVM_DEV_ARM_VGIC_GRP_CTRL,
-                          KVM_DEV_ARM_VGIC_CTRL_INIT, 0, 0, 1);
-    }
-
     /* Distributor */
     kvm_arm_register_device(&s->iomem,
                             (KVM_ARM_DEVICE_VGIC_V2 << KVM_ARM_DEVICE_ID_SHIFT)
diff --git a/hw/intc/vgic_common.h b/hw/intc/vgic_common.h
new file mode 100644
index 0000000..80d919e
--- /dev/null
+++ b/hw/intc/vgic_common.h
@@ -0,0 +1,35 @@
+/*
+ * ARM KVM vGIC utility functions
+ *
+ * Copyright (c) 2015 Samsung Electronics
+ * Written by Pavel Fedin
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef QEMU_ARM_VGIC_COMMON_H
+#define QEMU_ARM_VGIC_COMMON_H
+
+/**
+ * kvm_arm_gic_set_irq - Send an IRQ to the in-kernel vGIC
+ * @num_irq: Total number of IRQs configured for the GIC instance
+ * @irq: qemu internal IRQ line number:
+ *  [0..N-1] : external interrupts
+ *  [N..N+31] : PPI (internal) interrupts for CPU 0
+ *  [N+32..N+63] : PPI (internal interrupts for CPU 1
+ * @level: level of the IRQ line.
+ */
+void kvm_arm_gic_set_irq(uint32_t num_irq, int irq, int level);
+
+#endif
diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
index 983e99e..2a58b4d 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -240,6 +240,32 @@ int kvm_device_ioctl(int fd, int type, ...);
 int kvm_vm_check_attr(KVMState *s, uint32_t group, uint64_t attr);
 
 /**
+ * kvm_device_check_attr - check for existence of a specific device attribute
+ * @fd: The device file descriptor
+ * @group: the group
+ * @attr: the attribute of that group to query for
+ *
+ * Returns: 1 if the attribute exists
+ *          0 if the attribute either does not exist or if the vm device
+ *            interface is unavailable
+ */
+int kvm_device_check_attr(int fd, uint32_t group, uint64_t attr);
+
+/**
+ * kvm_device_access - set or get value of a specific vm attribute
+ * @fd: The device file descriptor
+ * @group: the group
+ * @attr: the attribute of that group to set or get
+ * @val: pointer to a storage area for the value
+ * @write: true for set and false for get operation
+ *
+ * This function is not allowed to fail. Use kvm_device_check_attr()
+ * in order to check for the availability of optional attributes.
+ */
+void kvm_device_access(int fd, int group, uint64_t attr,
+                       void *val, bool write);
+
+/**
  * kvm_create_device - create a KVM device for the device control API
  * @KVMState: The KVMState pointer
  * @type: The KVM device type (see Documentation/virtual/kvm/devices in the
diff --git a/kvm-all.c b/kvm-all.c
index c6f5128..f0b0e90 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -24,6 +24,7 @@
 #include "qemu/atomic.h"
 #include "qemu/option.h"
 #include "qemu/config-file.h"
+#include "qemu/error-report.h"
 #include "hw/hw.h"
 #include "hw/pci/msi.h"
 #include "hw/s390x/adapter.h"
@@ -2002,6 +2003,39 @@ int kvm_vm_check_attr(KVMState *s, uint32_t group, 
uint64_t attr)
     return ret ? 0 : 1;
 }
 
+int kvm_device_check_attr(int dev_fd, uint32_t group, uint64_t attr)
+{
+    struct kvm_device_attr attribute = {
+        .group = group,
+        .attr = attr,
+        .flags = 0,
+    };
+
+    return kvm_device_ioctl(dev_fd, KVM_HAS_DEVICE_ATTR, &attribute) ? 0 : 1;
+}
+
+void kvm_device_access(int fd, int group, uint64_t attr,
+                       void *val, bool write)
+{
+    struct kvm_device_attr kvmattr;
+    int err;
+
+    kvmattr.flags = 0;
+    kvmattr.group = group;
+    kvmattr.attr = attr;
+    kvmattr.addr = (uintptr_t)val;
+
+    err = kvm_device_ioctl(fd,
+                           write ? KVM_SET_DEVICE_ATTR : KVM_GET_DEVICE_ATTR,
+                           &kvmattr);
+    if (err < 0) {
+        error_report("KVM_%s_DEVICE_ATTR failed: %s\n"
+                     "Group %d attr 0x%016zX", write ? "SET" : "GET",
+                     strerror(-err), group, attr);
+        abort();
+    }
+}
+
 int kvm_has_sync_mmu(void)
 {
     return kvm_check_extension(kvm_state, KVM_CAP_SYNC_MMU);
-- 
2.4.4