[patch 1/3] KVM: x86: add ioctls to get/set PIO state

[Marcelo Tosatti <mtosatti@redhat.com>]

[-- Attachment #1: kernel-get-set-pio --]
[-- Type: text/plain, Size: 3748 bytes --]

A vcpu can be stopped after handling IO in userspace,
but before returning to kernel to finish processing.

Add ioctls to get/set the PIO state.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/arch/x86/include/asm/kvm.h b/arch/x86/include/asm/kvm.h
index f46b79f..c1b2b8c 100644
--- a/arch/x86/include/asm/kvm.h
+++ b/arch/x86/include/asm/kvm.h
@@ -284,4 +284,18 @@ struct kvm_vcpu_events {
 	__u32 reserved[10];
 };
 
+struct kvm_pio_request {
+	__u64 guest_gva;
+	__u32 count;
+	__u32 cur_count;
+	__u16 port;
+	__u8 size;
+	__u8 in;
+	__u8 string;
+	__u8 down;
+	__u8 rep;
+	__u8 pad;
+};
+
+
 #endif /* _ASM_X86_KVM_H */
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 1522337..28f31e1 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -222,18 +222,6 @@ struct kvm_pv_mmu_op_buffer {
 	char buf[512] __aligned(sizeof(long));
 };
 
-struct kvm_pio_request {
-	unsigned long count;
-	int cur_count;
-	gva_t guest_gva;
-	int in;
-	int port;
-	int size;
-	int string;
-	int down;
-	int rep;
-};
-
 /*
  * x86 supports 3 paging modes (4-level 64-bit, 3-level 64-bit, and 2-level
  * 32-bit).  The kvm_mmu structure abstracts the details of the current mmu
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ac8672f..99d991a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1575,6 +1575,9 @@ int kvm_dev_ioctl_check_extension(long ext)
 	case KVM_CAP_COALESCED_MMIO:
 		r = KVM_COALESCED_MMIO_PAGE_OFFSET;
 		break;
+	case KVM_CAP_PIO:
+		r = KVM_PIO_PAGE_OFFSET;
+		break;
 	case KVM_CAP_VAPIC:
 		r = !kvm_x86_ops->cpu_has_accelerated_tpr();
 		break;
@@ -2175,6 +2178,26 @@ static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu,
 	return 0;
 }
 
+static void kvm_vcpu_ioctl_x86_get_pio(struct kvm_vcpu *vcpu,
+				       struct kvm_pio_request *pio)
+{
+	vcpu_load(vcpu);
+	memcpy(pio, &vcpu->arch.pio, sizeof(struct kvm_pio_request));
+	vcpu_put(vcpu);
+}
+
+static int kvm_vcpu_ioctl_x86_set_pio(struct kvm_vcpu *vcpu,
+				      struct kvm_pio_request *pio)
+{
+	if (!pio->string && pio->size > 4)
+		return -EINVAL;
+
+	vcpu_load(vcpu);
+	memcpy(&vcpu->arch.pio, pio, sizeof(struct kvm_pio_request));
+	vcpu_put(vcpu);
+	return 0;
+}
+
 long kvm_arch_vcpu_ioctl(struct file *filp,
 			 unsigned int ioctl, unsigned long arg)
 {
@@ -2353,6 +2376,27 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 		r = kvm_vcpu_ioctl_x86_set_vcpu_events(vcpu, &events);
 		break;
 	}
+	case KVM_SET_VCPU_PIO: {
+		struct kvm_pio_request pio;
+
+		r = -EFAULT;
+		if (copy_from_user(&pio, argp, sizeof(struct kvm_pio_request)))
+			break;
+
+		r = kvm_vcpu_ioctl_x86_set_pio(vcpu, &pio);
+		break;
+	}
+	case KVM_GET_VCPU_PIO: {
+		struct kvm_pio_request pio;
+
+		kvm_vcpu_ioctl_x86_get_pio(vcpu, &pio);
+		
+		r = -EFAULT;
+		if (copy_to_user(argp, &pio, sizeof(struct kvm_pio_request)))
+			break;
+		r = 0;
+		break;
+	}
 	default:
 		r = -EINVAL;
 	}
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 4c4937e..0b56d41 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -500,6 +500,7 @@ struct kvm_ioeventfd {
 #define KVM_CAP_HYPERV 44
 #define KVM_CAP_HYPERV_VAPIC 45
 #define KVM_CAP_HYPERV_SPIN 46
+#define KVM_CAP_PIO 47
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
@@ -686,6 +687,8 @@ struct kvm_clock_data {
 /* Available with KVM_CAP_VCPU_EVENTS */
 #define KVM_GET_VCPU_EVENTS       _IOR(KVMIO,  0x9f, struct kvm_vcpu_events)
 #define KVM_SET_VCPU_EVENTS       _IOW(KVMIO,  0xa0, struct kvm_vcpu_events)
+#define KVM_GET_VCPU_PIO          _IOR(KVMIO,  0xa1, struct kvm_pio_request)
+#define KVM_SET_VCPU_PIO          _IOW(KVMIO,  0xa2, struct kvm_pio_request)
 
 #define KVM_DEV_ASSIGN_ENABLE_IOMMU	(1 << 0)