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KVM: s390: migrate vcpu interrupt state
authorJens Freimann <jfrei@linux.vnet.ibm.com>
Mon, 24 Nov 2014 16:13:46 +0000 (17:13 +0100)
committerChristian Borntraeger <borntraeger@de.ibm.com>
Tue, 31 Mar 2015 19:07:31 +0000 (21:07 +0200)
This patch adds support to migrate vcpu interrupts. Two new vcpu ioctls
are added which get/set the complete status of pending interrupts in one
go. The ioctls are marked as available with the new capability
KVM_CAP_S390_IRQ_STATE.

We can not use a ONEREG, as the number of pending local interrupts is not
constant and depends on the number of CPUs.

To retrieve the interrupt state we add an ioctl KVM_S390_GET_IRQ_STATE.
Its input parameter is a pointer to a struct kvm_s390_irq_state which
has a buffer and length.  For all currently pending interrupts, we copy
a struct kvm_s390_irq into the buffer and pass it to userspace.

To store interrupt state into a buffer provided by userspace, we add an
ioctl KVM_S390_SET_IRQ_STATE. It passes a struct kvm_s390_irq_state into
the kernel and injects all interrupts contained in the buffer.

Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Documentation/virtual/kvm/api.txt
arch/s390/kvm/interrupt.c
arch/s390/kvm/kvm-s390.c
arch/s390/kvm/kvm-s390.h
include/uapi/linux/kvm.h

index a7c651d..18fb763 100644 (file)
@@ -2875,6 +2875,67 @@ KVM_S390_MCHK - machine check interrupt; parameters in .mchk
 
 Note that the vcpu ioctl is asynchronous to vcpu execution.
 
+4.94 KVM_S390_GET_IRQ_STATE
+
+Capability: KVM_CAP_S390_IRQ_STATE
+Architectures: s390
+Type: vcpu ioctl
+Parameters: struct kvm_s390_irq_state (out)
+Returns: >= number of bytes copied into buffer,
+         -EINVAL if buffer size is 0,
+         -ENOBUFS if buffer size is too small to fit all pending interrupts,
+         -EFAULT if the buffer address was invalid
+
+This ioctl allows userspace to retrieve the complete state of all currently
+pending interrupts in a single buffer. Use cases include migration
+and introspection. The parameter structure contains the address of a
+userspace buffer and its length:
+
+struct kvm_s390_irq_state {
+       __u64 buf;
+       __u32 flags;
+       __u32 len;
+       __u32 reserved[4];
+};
+
+Userspace passes in the above struct and for each pending interrupt a
+struct kvm_s390_irq is copied to the provided buffer.
+
+If -ENOBUFS is returned the buffer provided was too small and userspace
+may retry with a bigger buffer.
+
+4.95 KVM_S390_SET_IRQ_STATE
+
+Capability: KVM_CAP_S390_IRQ_STATE
+Architectures: s390
+Type: vcpu ioctl
+Parameters: struct kvm_s390_irq_state (in)
+Returns: 0 on success,
+         -EFAULT if the buffer address was invalid,
+         -EINVAL for an invalid buffer length (see below),
+         -EBUSY if there were already interrupts pending,
+         errors occurring when actually injecting the
+          interrupt. See KVM_S390_IRQ.
+
+This ioctl allows userspace to set the complete state of all cpu-local
+interrupts currently pending for the vcpu. It is intended for restoring
+interrupt state after a migration. The input parameter is a userspace buffer
+containing a struct kvm_s390_irq_state:
+
+struct kvm_s390_irq_state {
+       __u64 buf;
+       __u32 len;
+       __u32 pad;
+};
+
+The userspace memory referenced by buf contains a struct kvm_s390_irq
+for each interrupt to be injected into the guest.
+If one of the interrupts could not be injected for some reason the
+ioctl aborts.
+
+len must be a multiple of sizeof(struct kvm_s390_irq). It must be > 0
+and it must not exceed (max_vcpus + 32) * sizeof(struct kvm_s390_irq),
+which is the maximum number of possibly pending cpu-local interrupts.
 
 5. The kvm_run structure
 ------------------------
index bc09880..9de4726 100644 (file)
@@ -2123,3 +2123,143 @@ int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e, struct kvm *kvm,
 {
        return -EINVAL;
 }
+
+int kvm_s390_set_irq_state(struct kvm_vcpu *vcpu, void __user *irqstate, int len)
+{
+       struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int;
+       struct kvm_s390_irq *buf;
+       int r = 0;
+       int n;
+
+       buf = vmalloc(len);
+       if (!buf)
+               return -ENOMEM;
+
+       if (copy_from_user((void *) buf, irqstate, len)) {
+               r = -EFAULT;
+               goto out_free;
+       }
+
+       /*
+        * Don't allow setting the interrupt state
+        * when there are already interrupts pending
+        */
+       spin_lock(&li->lock);
+       if (li->pending_irqs) {
+               r = -EBUSY;
+               goto out_unlock;
+       }
+
+       for (n = 0; n < len / sizeof(*buf); n++) {
+               r = do_inject_vcpu(vcpu, &buf[n]);
+               if (r)
+                       break;
+       }
+
+out_unlock:
+       spin_unlock(&li->lock);
+out_free:
+       vfree(buf);
+
+       return r;
+}
+
+static void store_local_irq(struct kvm_s390_local_interrupt *li,
+                           struct kvm_s390_irq *irq,
+                           unsigned long irq_type)
+{
+       switch (irq_type) {
+       case IRQ_PEND_MCHK_EX:
+       case IRQ_PEND_MCHK_REP:
+               irq->type = KVM_S390_MCHK;
+               irq->u.mchk = li->irq.mchk;
+               break;
+       case IRQ_PEND_PROG:
+               irq->type = KVM_S390_PROGRAM_INT;
+               irq->u.pgm = li->irq.pgm;
+               break;
+       case IRQ_PEND_PFAULT_INIT:
+               irq->type = KVM_S390_INT_PFAULT_INIT;
+               irq->u.ext = li->irq.ext;
+               break;
+       case IRQ_PEND_EXT_EXTERNAL:
+               irq->type = KVM_S390_INT_EXTERNAL_CALL;
+               irq->u.extcall = li->irq.extcall;
+               break;
+       case IRQ_PEND_EXT_CLOCK_COMP:
+               irq->type = KVM_S390_INT_CLOCK_COMP;
+               break;
+       case IRQ_PEND_EXT_CPU_TIMER:
+               irq->type = KVM_S390_INT_CPU_TIMER;
+               break;
+       case IRQ_PEND_SIGP_STOP:
+               irq->type = KVM_S390_SIGP_STOP;
+               irq->u.stop = li->irq.stop;
+               break;
+       case IRQ_PEND_RESTART:
+               irq->type = KVM_S390_RESTART;
+               break;
+       case IRQ_PEND_SET_PREFIX:
+               irq->type = KVM_S390_SIGP_SET_PREFIX;
+               irq->u.prefix = li->irq.prefix;
+               break;
+       }
+}
+
+int kvm_s390_get_irq_state(struct kvm_vcpu *vcpu, __u8 __user *buf, int len)
+{
+       uint8_t sigp_ctrl = vcpu->kvm->arch.sca->cpu[vcpu->vcpu_id].sigp_ctrl;
+       unsigned long sigp_emerg_pending[BITS_TO_LONGS(KVM_MAX_VCPUS)];
+       struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int;
+       unsigned long pending_irqs;
+       struct kvm_s390_irq irq;
+       unsigned long irq_type;
+       int cpuaddr;
+       int n = 0;
+
+       spin_lock(&li->lock);
+       pending_irqs = li->pending_irqs;
+       memcpy(&sigp_emerg_pending, &li->sigp_emerg_pending,
+              sizeof(sigp_emerg_pending));
+       spin_unlock(&li->lock);
+
+       for_each_set_bit(irq_type, &pending_irqs, IRQ_PEND_COUNT) {
+               memset(&irq, 0, sizeof(irq));
+               if (irq_type == IRQ_PEND_EXT_EMERGENCY)
+                       continue;
+               if (n + sizeof(irq) > len)
+                       return -ENOBUFS;
+               store_local_irq(&vcpu->arch.local_int, &irq, irq_type);
+               if (copy_to_user(&buf[n], &irq, sizeof(irq)))
+                       return -EFAULT;
+               n += sizeof(irq);
+       }
+
+       if (test_bit(IRQ_PEND_EXT_EMERGENCY, &pending_irqs)) {
+               for_each_set_bit(cpuaddr, sigp_emerg_pending, KVM_MAX_VCPUS) {
+                       memset(&irq, 0, sizeof(irq));
+                       if (n + sizeof(irq) > len)
+                               return -ENOBUFS;
+                       irq.type = KVM_S390_INT_EMERGENCY;
+                       irq.u.emerg.code = cpuaddr;
+                       if (copy_to_user(&buf[n], &irq, sizeof(irq)))
+                               return -EFAULT;
+                       n += sizeof(irq);
+               }
+       }
+
+       if ((sigp_ctrl & SIGP_CTRL_C) &&
+           (atomic_read(&vcpu->arch.sie_block->cpuflags) &
+            CPUSTAT_ECALL_PEND)) {
+               if (n + sizeof(irq) > len)
+                       return -ENOBUFS;
+               memset(&irq, 0, sizeof(irq));
+               irq.type = KVM_S390_INT_EXTERNAL_CALL;
+               irq.u.extcall.code = sigp_ctrl & SIGP_CTRL_SCN_MASK;
+               if (copy_to_user(&buf[n], &irq, sizeof(irq)))
+                       return -EFAULT;
+               n += sizeof(irq);
+       }
+
+       return n;
+}
index 8bc25d4..3040b14 100644 (file)
@@ -41,6 +41,9 @@
 #include "trace-s390.h"
 
 #define MEM_OP_MAX_SIZE 65536  /* Maximum transfer size for KVM_S390_MEM_OP */
+#define LOCAL_IRQS 32
+#define VCPU_IRQS_MAX_BUF (sizeof(struct kvm_s390_irq) * \
+                          (KVM_MAX_VCPUS + LOCAL_IRQS))
 
 #define VCPU_STAT(x) offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU
 
@@ -181,6 +184,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
        case KVM_CAP_S390_USER_SIGP:
        case KVM_CAP_S390_USER_STSI:
        case KVM_CAP_S390_SKEYS:
+       case KVM_CAP_S390_IRQ_STATE:
                r = 1;
                break;
        case KVM_CAP_S390_MEM_OP:
@@ -2500,6 +2504,38 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
                        r = -EFAULT;
                break;
        }
+       case KVM_S390_SET_IRQ_STATE: {
+               struct kvm_s390_irq_state irq_state;
+
+               r = -EFAULT;
+               if (copy_from_user(&irq_state, argp, sizeof(irq_state)))
+                       break;
+               if (irq_state.len > VCPU_IRQS_MAX_BUF ||
+                   irq_state.len == 0 ||
+                   irq_state.len % sizeof(struct kvm_s390_irq) > 0) {
+                       r = -EINVAL;
+                       break;
+               }
+               r = kvm_s390_set_irq_state(vcpu,
+                                          (void __user *) irq_state.buf,
+                                          irq_state.len);
+               break;
+       }
+       case KVM_S390_GET_IRQ_STATE: {
+               struct kvm_s390_irq_state irq_state;
+
+               r = -EFAULT;
+               if (copy_from_user(&irq_state, argp, sizeof(irq_state)))
+                       break;
+               if (irq_state.len == 0) {
+                       r = -EINVAL;
+                       break;
+               }
+               r = kvm_s390_get_irq_state(vcpu,
+                                          (__u8 __user *)  irq_state.buf,
+                                          irq_state.len);
+               break;
+       }
        default:
                r = -ENOTTY;
        }
index 343644a..ca108b9 100644 (file)
@@ -272,6 +272,10 @@ int kvm_s390_ext_call_pending(struct kvm_vcpu *vcpu);
 extern struct kvm_device_ops kvm_flic_ops;
 int kvm_s390_is_stop_irq_pending(struct kvm_vcpu *vcpu);
 void kvm_s390_clear_stop_irq(struct kvm_vcpu *vcpu);
+int kvm_s390_set_irq_state(struct kvm_vcpu *vcpu,
+                          void __user *buf, int len);
+int kvm_s390_get_irq_state(struct kvm_vcpu *vcpu,
+                          __u8 __user *buf, int len);
 
 /* implemented in guestdbg.c */
 void kvm_s390_backup_guest_per_regs(struct kvm_vcpu *vcpu);
index c0632e8..c045c72 100644 (file)
@@ -558,6 +558,13 @@ struct kvm_s390_irq {
        } u;
 };
 
+struct kvm_s390_irq_state {
+       __u64 buf;
+       __u32 flags;
+       __u32 len;
+       __u32 reserved[4];
+};
+
 /* for KVM_SET_GUEST_DEBUG */
 
 #define KVM_GUESTDBG_ENABLE            0x00000001
@@ -803,6 +810,7 @@ struct kvm_ppc_smmu_info {
 #define KVM_CAP_S390_USER_STSI 109
 #define KVM_CAP_S390_SKEYS 110
 #define KVM_CAP_S390_INJECT_IRQ 113
+#define KVM_CAP_S390_IRQ_STATE 114
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
@@ -1185,6 +1193,9 @@ struct kvm_s390_ucas_mapping {
 #define KVM_S390_SET_SKEYS      _IOW(KVMIO, 0xb3, struct kvm_s390_skeys)
 /* Available with KVM_CAP_S390_INJECT_IRQ */
 #define KVM_S390_IRQ              _IOW(KVMIO,  0xb4, struct kvm_s390_irq)
+/* Available with KVM_CAP_S390_IRQ_STATE */
+#define KVM_S390_SET_IRQ_STATE   _IOW(KVMIO, 0xb5, struct kvm_s390_irq_state)
+#define KVM_S390_GET_IRQ_STATE   _IOW(KVMIO, 0xb6, struct kvm_s390_irq_state)
 
 #define KVM_DEV_ASSIGN_ENABLE_IOMMU    (1 << 0)
 #define KVM_DEV_ASSIGN_PCI_2_3         (1 << 1)