KVM: Add get/set irqchip ioctls for in-kernel PIC live migration support

This patch adds two new ioctls to dump and write kernel irqchips for
save/restore and live migration. PIC s/r and l/m is implemented in this
patch.

Signed-off-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: Qing He <qing.he@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

4 files changed, 124 insertions, 0 deletions

diff --git a/drivers/kvm/i8259.c b/drivers/kvm/i8259.c
index ee6030dc5c04..a679157bc599 100644
--- a/drivers/kvm/i8259.c
+++ b/drivers/kvm/i8259.c
@@ -119,6 +119,11 @@ static void pic_update_irq(struct kvm_pic *s)
                 s->irq_request(s->irq_request_opaque, 0);
 }
 
+void kvm_pic_update_irq(struct kvm_pic *s)
+{
+        pic_update_irq(s);
+}
+
 void kvm_pic_set_irq(void *opaque, int irq, int level)
 {
         struct kvm_pic *s = opaque;
diff --git a/drivers/kvm/irq.h b/drivers/kvm/irq.h
index 6ed856a41e23..4034f6576cd9 100644
--- a/drivers/kvm/irq.h
+++ b/drivers/kvm/irq.h
@@ -59,6 +59,7 @@ void kvm_pic_set_irq(void *opaque, int irq, int level);
 int kvm_pic_read_irq(struct kvm_pic *s);
 int kvm_cpu_get_interrupt(struct kvm_vcpu *v);
 int kvm_cpu_has_interrupt(struct kvm_vcpu *v);
+void kvm_pic_update_irq(struct kvm_pic *s);
 
 #define IOAPIC_NUM_PINS  24
 #define IOAPIC_VERSION_ID 0x11  /* IOAPIC version */
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 5063b3addbbf..6e2c5f3f33fb 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -897,6 +897,53 @@ out:
         return r;
 }
 
+static int kvm_vm_ioctl_get_irqchip(struct kvm *kvm, struct kvm_irqchip *chip)
+{
+        int r;
+
+        r = 0;
+        switch (chip->chip_id) {
+        case KVM_IRQCHIP_PIC_MASTER:
+                memcpy (&chip->chip.pic,
+                        &pic_irqchip(kvm)->pics[0],
+                        sizeof(struct kvm_pic_state));
+                break;
+        case KVM_IRQCHIP_PIC_SLAVE:
+                memcpy (&chip->chip.pic,
+                        &pic_irqchip(kvm)->pics[1],
+                        sizeof(struct kvm_pic_state));
+                break;
+        default:
+                r = -EINVAL;
+                break;
+        }
+        return r;
+}
+
+static int kvm_vm_ioctl_set_irqchip(struct kvm *kvm, struct kvm_irqchip *chip)
+{
+        int r;
+
+        r = 0;
+        switch (chip->chip_id) {
+        case KVM_IRQCHIP_PIC_MASTER:
+                memcpy (&pic_irqchip(kvm)->pics[0],
+                        &chip->chip.pic,
+                        sizeof(struct kvm_pic_state));
+                break;
+        case KVM_IRQCHIP_PIC_SLAVE:
+                memcpy (&pic_irqchip(kvm)->pics[1],
+                        &chip->chip.pic,
+                        sizeof(struct kvm_pic_state));
+                break;
+        default:
+                r = -EINVAL;
+                break;
+        }
+        kvm_pic_update_irq(pic_irqchip(kvm));
+        return r;
+}
+
 static gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn)
 {
         int i;
@@ -2835,6 +2882,41 @@ static long kvm_vm_ioctl(struct file *filp,
                 }
                 break;
         }
+        case KVM_GET_IRQCHIP: {
+                /* 0: PIC master, 1: PIC slave, 2: IOAPIC */
+                struct kvm_irqchip chip;
+
+                r = -EFAULT;
+                if (copy_from_user(&chip, argp, sizeof chip))
+                        goto out;
+                r = -ENXIO;
+                if (!irqchip_in_kernel(kvm))
+                        goto out;
+                r = kvm_vm_ioctl_get_irqchip(kvm, &chip);
+                if (r)
+                        goto out;
+                r = -EFAULT;
+                if (copy_to_user(argp, &chip, sizeof chip))
+                        goto out;
+                r = 0;
+                break;
+        }
+        case KVM_SET_IRQCHIP: {
+                /* 0: PIC master, 1: PIC slave, 2: IOAPIC */
+                struct kvm_irqchip chip;
+
+                r = -EFAULT;
+                if (copy_from_user(&chip, argp, sizeof chip))
+                        goto out;
+                r = -ENXIO;
+                if (!irqchip_in_kernel(kvm))
+                        goto out;
+                r = kvm_vm_ioctl_set_irqchip(kvm, &chip);
+                if (r)
+                        goto out;
+                r = 0;
+                break;
+        }
         default:
                 ;
         }
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index b0a13d1b34cc..6560f11870fd 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -45,6 +45,40 @@ struct kvm_irq_level {
         __u32 level;
 };
 
+/* for KVM_GET_IRQCHIP / KVM_SET_IRQCHIP */
+struct kvm_pic_state {
+        __u8 last_irr;  /* edge detection */
+        __u8 irr;               /* interrupt request register */
+        __u8 imr;               /* interrupt mask register */
+        __u8 isr;               /* interrupt service register */
+        __u8 priority_add;      /* highest irq priority */
+        __u8 irq_base;
+        __u8 read_reg_select;
+        __u8 poll;
+        __u8 special_mask;
+        __u8 init_state;
+        __u8 auto_eoi;
+        __u8 rotate_on_auto_eoi;
+        __u8 special_fully_nested_mode;
+        __u8 init4;             /* true if 4 byte init */
+        __u8 elcr;              /* PIIX edge/trigger selection */
+        __u8 elcr_mask;
+};
+
+enum kvm_irqchip_id {
+        KVM_IRQCHIP_PIC_MASTER   = 0,
+        KVM_IRQCHIP_PIC_SLAVE    = 1,
+};
+
+struct kvm_irqchip {
+        __u32 chip_id;
+        __u32 pad;
+        union {
+                char dummy[512];  /* reserving space */
+                struct kvm_pic_state pic;
+        } chip;
+};
+
 enum kvm_exit_reason {
         KVM_EXIT_UNKNOWN          = 0,
         KVM_EXIT_EXCEPTION        = 1,
@@ -299,6 +333,8 @@ struct kvm_signal_mask {
 /* Device model IOC */
 #define KVM_CREATE_IRQCHIP        _IO(KVMIO,  0x60)
 #define KVM_IRQ_LINE              _IOW(KVMIO, 0x61, struct kvm_irq_level)
+#define KVM_GET_IRQCHIP           _IOWR(KVMIO, 0x62, struct kvm_irqchip)
+#define KVM_SET_IRQCHIP           _IOR(KVMIO,  0x63, struct kvm_irqchip)
 
 /*
  * ioctls for vcpu fds