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[Qemu-devel] [PATCH v2 2/2] KVM: s390: add floating irq controller


From: Jens Freimann
Subject: [Qemu-devel] [PATCH v2 2/2] KVM: s390: add floating irq controller
Date: Fri, 6 Sep 2013 14:19:17 +0200

This patch adds a floating irq controller as a kvm_device.
It will be necessary for migration of floating interrupts as well
as for hardening the reset code by allowing user space to explicitly
remove all pending floating interrupts.

Signed-off-by: Jens Freimann <address@hidden>
Reviewed-by: Cornelia Huck <address@hidden>
---
 Documentation/virtual/kvm/devices/s390_flic.txt |  36 +++
 arch/s390/include/asm/kvm_host.h                |   1 +
 arch/s390/include/uapi/asm/kvm.h                |   5 +
 arch/s390/kvm/interrupt.c                       | 304 ++++++++++++++++++++----
 arch/s390/kvm/kvm-s390.c                        |   1 +
 include/linux/kvm_host.h                        |   1 +
 include/uapi/linux/kvm.h                        |   2 +
 virt/kvm/kvm_main.c                             |   5 +
 8 files changed, 304 insertions(+), 51 deletions(-)

diff --git a/Documentation/virtual/kvm/devices/s390_flic.txt 
b/Documentation/virtual/kvm/devices/s390_flic.txt
new file mode 100644
index 0000000..06aef31
--- /dev/null
+++ b/Documentation/virtual/kvm/devices/s390_flic.txt
@@ -0,0 +1,36 @@
+FLIC (floating interrupt controller)
+====================================
+
+FLIC handles floating (non per-cpu) interrupts, i.e.  I/O, service and some
+machine check interruptions. All interrupts are stored in a per-vm list of
+pending interrupts. FLIC performs operations on this list.
+
+Only one FLIC instance may be instantiated.
+
+FLIC provides support to
+- add/delete interrupts (KVM_DEV_FLIC_ENQUEUE and _DEQUEUE)
+- purge all pending floating interrupts (KVM_DEV_FLIC_CLEAR_IRQS)
+
+Groups:
+  KVM_DEV_FLIC_ENQUEUE
+    Adds one interrupt to the list of pending floating interrupts. Interrupts
+    are taken from this list for injection into the guest. attr contains
+    a struct kvm_s390_irq which contains all data relevant for
+    interrupt injection.
+    The format of the data structure kvm_s390_irq as it is copied from 
userspace
+    is defined in usr/include/linux/kvm.h.
+    For historic reasons list members are stored in a different data 
structure, i.e.
+    we need to copy the relevant data into a struct kvm_s390_interrupt_info
+    which can then be added to the list.
+
+  KVM_DEV_FLIC_DEQUEUE
+    Takes one element off the pending interrupts list and copies it into 
userspace.
+    Dequeued interrupts are not injected into the guest.
+    attr->addr contains the userspace address of a struct kvm_s390_irq.
+    List elements are stored in the format of struct kvm_s390_interrupt_info
+    (arch/s390/include/asm/kvm_host.h) and are copied into a struct 
kvm_s390_irq
+    (usr/include/linux/kvm.h)
+
+  KVM_DEV_FLIC_CLEAR_IRQS
+    Simply deletes all elements from the list of currently pending floating 
interrupts.
+    No interrupts are injected into the guest.
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index adb05c5..e1cc166 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -238,6 +238,7 @@ struct kvm_arch{
        struct sca_block *sca;
        debug_info_t *dbf;
        struct kvm_s390_float_interrupt float_int;
+       struct kvm_device *flic;
        struct gmap *gmap;
        int css_support;
 };
diff --git a/arch/s390/include/uapi/asm/kvm.h b/arch/s390/include/uapi/asm/kvm.h
index d25da59..33d52b8 100644
--- a/arch/s390/include/uapi/asm/kvm.h
+++ b/arch/s390/include/uapi/asm/kvm.h
@@ -16,6 +16,11 @@
 
 #define __KVM_S390
 
+/* Device control API: s390-specific devices */
+#define KVM_DEV_FLIC_DEQUEUE 1
+#define KVM_DEV_FLIC_ENQUEUE 2
+#define KVM_DEV_FLIC_CLEAR_IRQS 3
+
 /* for KVM_GET_REGS and KVM_SET_REGS */
 struct kvm_regs {
        /* general purpose regs for s390 */
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 7f35cb3..d6d5e36 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -656,53 +656,86 @@ struct kvm_s390_interrupt_info 
*kvm_s390_get_io_int(struct kvm *kvm,
        return inti;
 }
 
-int kvm_s390_inject_vm(struct kvm *kvm,
-                      struct kvm_s390_interrupt *s390int)
+static void __inject_vm(struct kvm *kvm, struct kvm_s390_interrupt_info *inti)
 {
        struct kvm_s390_local_interrupt *li;
        struct kvm_s390_float_interrupt *fi;
-       struct kvm_s390_interrupt_info *inti, *iter;
+       struct kvm_s390_interrupt_info *iter;
        int sigcpu;
 
+       mutex_lock(&kvm->lock);
+       fi = &kvm->arch.float_int;
+       spin_lock(&fi->lock);
+       if (!is_ioint(inti->type)) {
+               list_add_tail(&inti->list, &fi->list);
+       } else {
+               u64 isc_bits = int_word_to_isc_bits(inti->io.io_int_word);
+
+               /* Keep I/O interrupts sorted in isc order. */
+               list_for_each_entry(iter, &fi->list, list) {
+                       if (!is_ioint(iter->type))
+                               continue;
+                       if (int_word_to_isc_bits(iter->io.io_int_word)
+                                       <= isc_bits)
+                               continue;
+                       break;
+               }
+               list_add_tail(&inti->list, &iter->list);
+       }
+       atomic_set(&fi->active, 1);
+       sigcpu = find_first_bit(fi->idle_mask, KVM_MAX_VCPUS);
+       if (sigcpu == KVM_MAX_VCPUS) {
+               do {
+                       sigcpu = fi->next_rr_cpu++;
+                       if (sigcpu == KVM_MAX_VCPUS)
+                               sigcpu = fi->next_rr_cpu = 0;
+               } while (fi->local_int[sigcpu] == NULL);
+       }
+       li = fi->local_int[sigcpu];
+       spin_lock_bh(&li->lock);
+       atomic_set_mask(CPUSTAT_EXT_INT, li->cpuflags);
+       if (waitqueue_active(li->wq))
+               wake_up_interruptible(li->wq);
+       spin_unlock_bh(&li->lock);
+       spin_unlock(&fi->lock);
+       mutex_unlock(&kvm->lock);
+}
+
+int kvm_s390_inject_vm(struct kvm *kvm,
+                      struct kvm_s390_interrupt *s390int)
+{
+       struct kvm_s390_interrupt_info *inti;
+
        inti = kzalloc(sizeof(*inti), GFP_KERNEL);
        if (!inti)
                return -ENOMEM;
 
-       switch (s390int->type) {
+       inti->type = s390int->type;
+       switch (inti->type) {
        case KVM_S390_INT_VIRTIO:
                VM_EVENT(kvm, 5, "inject: virtio parm:%x,parm64:%llx",
                         s390int->parm, s390int->parm64);
-               inti->type = s390int->type;
                inti->ext.ext_params = s390int->parm;
                inti->ext.ext_params2 = s390int->parm64;
                break;
        case KVM_S390_INT_SERVICE:
                VM_EVENT(kvm, 5, "inject: sclp parm:%x", s390int->parm);
-               inti->type = s390int->type;
                inti->ext.ext_params = s390int->parm;
                break;
-       case KVM_S390_PROGRAM_INT:
-       case KVM_S390_SIGP_STOP:
-       case KVM_S390_INT_EXTERNAL_CALL:
-       case KVM_S390_INT_EMERGENCY:
-               kfree(inti);
-               return -EINVAL;
        case KVM_S390_MCHK:
                VM_EVENT(kvm, 5, "inject: machine check parm64:%llx",
                         s390int->parm64);
-               inti->type = s390int->type;
                inti->mchk.cr14 = s390int->parm; /* upper bits are not used */
                inti->mchk.mcic = s390int->parm64;
                break;
        case KVM_S390_INT_IO_MIN...KVM_S390_INT_IO_MAX:
-               if (s390int->type & IOINT_AI_MASK)
+               if (inti->type & IOINT_AI_MASK)
                        VM_EVENT(kvm, 5, "%s", "inject: I/O (AI)");
                else
                        VM_EVENT(kvm, 5, "inject: I/O css %x ss %x schid %04x",
                                 s390int->type & IOINT_CSSID_MASK,
                                 s390int->type & IOINT_SSID_MASK,
                                 s390int->type & IOINT_SCHID_MASK);
-               inti->type = s390int->type;
                inti->io.subchannel_id = s390int->parm >> 16;
                inti->io.subchannel_nr = s390int->parm & 0x0000ffffu;
                inti->io.io_int_parm = s390int->parm64 >> 32;
@@ -715,42 +748,7 @@ int kvm_s390_inject_vm(struct kvm *kvm,
        trace_kvm_s390_inject_vm(s390int->type, s390int->parm, s390int->parm64,
                                 2);
 
-       mutex_lock(&kvm->lock);
-       fi = &kvm->arch.float_int;
-       spin_lock(&fi->lock);
-       if (!is_ioint(inti->type))
-               list_add_tail(&inti->list, &fi->list);
-       else {
-               u64 isc_bits = int_word_to_isc_bits(inti->io.io_int_word);
-
-               /* Keep I/O interrupts sorted in isc order. */
-               list_for_each_entry(iter, &fi->list, list) {
-                       if (!is_ioint(iter->type))
-                               continue;
-                       if (int_word_to_isc_bits(iter->io.io_int_word)
-                           <= isc_bits)
-                               continue;
-                       break;
-               }
-               list_add_tail(&inti->list, &iter->list);
-       }
-       atomic_set(&fi->active, 1);
-       sigcpu = find_first_bit(fi->idle_mask, KVM_MAX_VCPUS);
-       if (sigcpu == KVM_MAX_VCPUS) {
-               do {
-                       sigcpu = fi->next_rr_cpu++;
-                       if (sigcpu == KVM_MAX_VCPUS)
-                               sigcpu = fi->next_rr_cpu = 0;
-               } while (fi->local_int[sigcpu] == NULL);
-       }
-       li = fi->local_int[sigcpu];
-       spin_lock_bh(&li->lock);
-       atomic_set_mask(CPUSTAT_EXT_INT, li->cpuflags);
-       if (waitqueue_active(li->wq))
-               wake_up_interruptible(li->wq);
-       spin_unlock_bh(&li->lock);
-       spin_unlock(&fi->lock);
-       mutex_unlock(&kvm->lock);
+       __inject_vm(kvm, inti);
        return 0;
 }
 
@@ -838,3 +836,207 @@ int kvm_s390_inject_vcpu(struct kvm_vcpu *vcpu,
        mutex_unlock(&vcpu->kvm->lock);
        return 0;
 }
+
+static void clear_floating_interrupts(struct kvm *kvm)
+{
+       struct kvm_s390_float_interrupt *fi;
+       struct kvm_s390_interrupt_info  *n, *inti = NULL;
+
+       mutex_lock(&kvm->lock);
+       fi = &kvm->arch.float_int;
+       spin_lock(&fi->lock);
+       list_for_each_entry_safe(inti, n, &fi->list, list) {
+               list_del(&inti->list);
+               kfree(inti);
+       }
+       atomic_set(&fi->active, 0);
+       spin_unlock(&fi->lock);
+       mutex_unlock(&kvm->lock);
+}
+
+static inline int copy_irq_to_user(struct kvm_s390_interrupt_info *inti,
+                                  u64 addr)
+{
+       struct kvm_s390_irq __user *uptr = (struct kvm_s390_irq __user *) addr;
+       void __user *target;
+       void *source;
+       u64 size;
+       int r = 0;
+
+       switch (inti->type) {
+       case KVM_S390_INT_VIRTIO:
+       case KVM_S390_INT_SERVICE:
+               source = &inti->ext;
+               target = &uptr->ext;
+               size = sizeof(inti->ext);
+               break;
+       case KVM_S390_INT_IO_MIN...KVM_S390_INT_IO_MAX:
+               source = &inti->io;
+               target = &uptr->io;
+               size = sizeof(inti->io);
+               break;
+       case KVM_S390_MCHK:
+               source = &inti->mchk;
+               target = &uptr->mchk;
+               size = sizeof(inti->mchk);
+               break;
+       case KVM_S390_INT_MAX:
+               goto out;
+       default:
+               return -EINVAL;
+       }
+
+       r = put_user(inti->type, (u64 __user *) &uptr->type);
+       if (copy_to_user(target, source, size))
+               r = -EFAULT;
+
+out:
+       return r;
+}
+
+static int dequeue_floating_irq(struct kvm *kvm, __u64 addr)
+{
+       struct kvm_s390_interrupt_info *inti;
+       struct kvm_s390_float_interrupt *fi;
+       int r = 0;
+
+
+       mutex_lock(&kvm->lock);
+       fi = &kvm->arch.float_int;
+       spin_lock(&fi->lock);
+       if (list_empty(&fi->list)) {
+               mutex_unlock(&kvm->lock);
+               spin_unlock(&fi->lock);
+               return -ENODATA;
+       }
+       inti = list_first_entry(&fi->list,
+                       struct kvm_s390_interrupt_info, list);
+       list_del(&inti->list);
+       spin_unlock(&fi->lock);
+       mutex_unlock(&kvm->lock);
+
+       r = copy_irq_to_user(inti, addr);
+
+       kfree(inti);
+       return r;
+}
+
+static int flic_get_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
+{
+       int r;
+
+       switch (attr->group) {
+       case KVM_DEV_FLIC_DEQUEUE:
+               r = dequeue_floating_irq(dev->kvm, attr->addr);
+               break;
+       default:
+               r = -EINVAL;
+       }
+
+       return r;
+}
+
+static inline int copy_irq_from_user(struct kvm_s390_interrupt_info *inti,
+                                    u64 addr)
+{
+       struct kvm_s390_irq __user *uptr = (struct kvm_s390_irq __user *) addr;
+       void *target = NULL;
+       void *source;
+       u64 size;
+       int r = 0;
+
+       if (get_user(inti->type, (u64 __user *)addr))
+               return -EFAULT;
+       switch (inti->type) {
+       case KVM_S390_INT_VIRTIO:
+       case KVM_S390_INT_SERVICE:
+               target = (void *) &inti->ext;
+               source = &uptr->ext;
+               size = sizeof(inti->ext);
+               break;
+       case KVM_S390_INT_IO_MIN...KVM_S390_INT_IO_MAX:
+               target = (void *) &inti->io;
+               source = &uptr->io;
+               size = sizeof(inti->io);
+               break;
+       case KVM_S390_MCHK:
+               target = (void *) &inti->mchk;
+               source = &uptr->mchk;
+               size = sizeof(inti->mchk);
+               break;
+       case KVM_S390_INT_MAX:
+               goto out;
+       default:
+               r = -EINVAL;
+               return r;
+       }
+
+       if (copy_from_user(target, source, size))
+               r = -EFAULT;
+
+out:
+       return r;
+}
+
+static int enqueue_floating_irq(struct kvm_device *dev,
+                                struct kvm_device_attr *attr)
+{
+       struct kvm_s390_interrupt_info *inti = NULL;
+       int r = 0;
+
+       inti = kzalloc(sizeof(*inti), GFP_KERNEL);
+       if (!inti)
+               return -ENOMEM;
+
+       r = copy_irq_from_user(inti, attr->addr);
+       if (r) {
+               kfree(inti);
+               return r;
+       }
+       __inject_vm(dev->kvm, inti);
+
+       return r;
+}
+
+static int flic_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr)
+{
+       int r = 0;
+
+       switch (attr->group) {
+       case KVM_DEV_FLIC_ENQUEUE:
+               r = enqueue_floating_irq(dev, attr);
+               break;
+       case KVM_DEV_FLIC_CLEAR_IRQS:
+               r = 0;
+               clear_floating_interrupts(dev->kvm);
+               break;
+       default:
+               r = -EINVAL;
+       }
+
+       return r;
+}
+
+static int flic_create(struct kvm_device *dev, u32 type)
+{
+       if (!dev)
+               return -EINVAL;
+       if (dev->kvm->arch.flic)
+               return -EINVAL;
+       dev->kvm->arch.flic = dev;
+       return 0;
+}
+
+static void flic_destroy(struct kvm_device *dev)
+{
+       dev->kvm->arch.flic = NULL;
+}
+
+/* s390 floating irq controller (flic) */
+struct kvm_device_ops kvm_flic_ops = {
+       .name = "kvm-flic",
+       .get_attr = flic_get_attr,
+       .set_attr = flic_set_attr,
+       .create = flic_create,
+       .destroy = flic_destroy,
+};
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 776dafe..760febf 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -157,6 +157,7 @@ int kvm_dev_ioctl_check_extension(long ext)
        case KVM_CAP_ENABLE_CAP:
        case KVM_CAP_S390_CSS_SUPPORT:
        case KVM_CAP_IOEVENTFD:
+       case KVM_CAP_DEVICE_CTRL:
                r = 1;
                break;
        case KVM_CAP_NR_VCPUS:
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index ca645a0..e89304d 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1065,6 +1065,7 @@ struct kvm_device *kvm_device_from_filp(struct file 
*filp);
 
 extern struct kvm_device_ops kvm_mpic_ops;
 extern struct kvm_device_ops kvm_xics_ops;
+extern struct kvm_device_ops kvm_flic_ops;
 
 #ifdef CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT
 
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index eeb08a1..9c8b457 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -426,6 +426,7 @@ struct kvm_s390_psw {
         ((ai) << 26))
 #define KVM_S390_INT_IO_MIN            0x00000000u
 #define KVM_S390_INT_IO_MAX            0xfffdffffu
+#define KVM_S390_INT_MAX               0xffffffffu
 
 
 struct kvm_s390_interrupt {
@@ -906,6 +907,7 @@ struct kvm_device_attr {
 #define KVM_DEV_TYPE_FSL_MPIC_20       1
 #define KVM_DEV_TYPE_FSL_MPIC_42       2
 #define KVM_DEV_TYPE_XICS              3
+#define KVM_DEV_TYPE_FLIC              4
 
 /*
  * ioctls for VM fds
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index bf040c4..79a2ecc 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2265,6 +2265,11 @@ static int kvm_ioctl_create_device(struct kvm *kvm,
                ops = &kvm_xics_ops;
                break;
 #endif
+#ifdef CONFIG_S390
+       case KVM_DEV_TYPE_FLIC:
+               ops = &kvm_flic_ops;
+               break;
+#endif
        default:
                return -ENODEV;
        }
-- 
1.8.3.4




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