KVM: Add save/restore supporting of in kernel PIT

Signed-off-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

5 files changed, 79 insertions, 0 deletions

diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index c7435093bbee..8642f9d1206a 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -288,6 +288,13 @@ static void pit_load_count(struct kvm *kvm, int channel, u32 val)
         }
 }
 
+void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val)
+{
+        mutex_lock(&kvm->arch.vpit->pit_state.lock);
+        pit_load_count(kvm, channel, val);
+        mutex_unlock(&kvm->arch.vpit->pit_state.lock);
+}
+
 static void pit_ioport_write(struct kvm_io_device *this,
                              gpa_t addr, int len, const void *data)
 {
diff --git a/arch/x86/kvm/i8254.h b/arch/x86/kvm/i8254.h
index d77d6b795a1f..fe09eced7783 100644
--- a/arch/x86/kvm/i8254.h
+++ b/arch/x86/kvm/i8254.h
@@ -55,6 +55,7 @@ struct kvm_pit {
 
 void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu);
 void kvm_pit_timer_intr_post(struct kvm_vcpu *vcpu, int vec);
+void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val);
 struct kvm_pit *kvm_create_pit(struct kvm *kvm);
 void kvm_free_pit(struct kvm *kvm);
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c33a4578132c..621a8e362fe7 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1504,6 +1504,23 @@ static int kvm_vm_ioctl_set_irqchip(struct kvm *kvm, struct kvm_irqchip *chip)
         return r;
 }
 
+static int kvm_vm_ioctl_get_pit(struct kvm *kvm, struct kvm_pit_state *ps)
+{
+        int r = 0;
+
+        memcpy(ps, &kvm->arch.vpit->pit_state, sizeof(struct kvm_pit_state));
+        return r;
+}
+
+static int kvm_vm_ioctl_set_pit(struct kvm *kvm, struct kvm_pit_state *ps)
+{
+        int r = 0;
+
+        memcpy(&kvm->arch.vpit->pit_state, ps, sizeof(struct kvm_pit_state));
+        kvm_pit_load_count(kvm, 0, ps->channels[0].count);
+        return r;
+}
+
 /*
  * Get (and clear) the dirty memory log for a memory slot.
  */
@@ -1657,6 +1674,37 @@ long kvm_arch_vm_ioctl(struct file *filp,
                 r = 0;
                 break;
         }
+        case KVM_GET_PIT: {
+                struct kvm_pit_state ps;
+                r = -EFAULT;
+                if (copy_from_user(&ps, argp, sizeof ps))
+                        goto out;
+                r = -ENXIO;
+                if (!kvm->arch.vpit)
+                        goto out;
+                r = kvm_vm_ioctl_get_pit(kvm, &ps);
+                if (r)
+                        goto out;
+                r = -EFAULT;
+                if (copy_to_user(argp, &ps, sizeof ps))
+                        goto out;
+                r = 0;
+                break;
+        }
+        case KVM_SET_PIT: {
+                struct kvm_pit_state ps;
+                r = -EFAULT;
+                if (copy_from_user(&ps, argp, sizeof ps))
+                        goto out;
+                r = -ENXIO;
+                if (!kvm->arch.vpit)
+                        goto out;
+                r = kvm_vm_ioctl_set_pit(kvm, &ps);
+                if (r)
+                        goto out;
+                r = 0;
+                break;
+        }
         default:
                 ;
         }
diff --git a/include/asm-x86/kvm.h b/include/asm-x86/kvm.h
index 7a71120426a3..12b4b25371d5 100644
--- a/include/asm-x86/kvm.h
+++ b/include/asm-x86/kvm.h
@@ -188,4 +188,25 @@ struct kvm_cpuid2 {
         struct kvm_cpuid_entry2 entries[0];
 };
 
+/* for KVM_GET_PIT and KVM_SET_PIT */
+struct kvm_pit_channel_state {
+        __u32 count; /* can be 65536 */
+        __u16 latched_count;
+        __u8 count_latched;
+        __u8 status_latched;
+        __u8 status;
+        __u8 read_state;
+        __u8 write_state;
+        __u8 write_latch;
+        __u8 rw_mode;
+        __u8 mode;
+        __u8 bcd;
+        __u8 gate;
+        __s64 count_load_time;
+};
+
+struct kvm_pit_state {
+        struct kvm_pit_channel_state channels[3];
+};
+
 #endif
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index cefa9a2c7b89..a2f3274016ee 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -260,6 +260,8 @@ struct kvm_vapic_addr {
 #define KVM_GET_IRQCHIP           _IOWR(KVMIO, 0x62, struct kvm_irqchip)
 #define KVM_SET_IRQCHIP           _IOR(KVMIO,  0x63, struct kvm_irqchip)
 #define KVM_CREATE_PIT            _IO(KVMIO,  0x64)
+#define KVM_GET_PIT               _IOWR(KVMIO, 0x65, struct kvm_pit_state)
+#define KVM_SET_PIT               _IOR(KVMIO,  0x66, struct kvm_pit_state)
 
 /*
  * ioctls for vcpu fds