[RFC PATCH 3/4] KVM: stats: Add ioctl commands to pull statistics in binary format

[Jing Zhang <jingzhangos@google.com>]

Three ioctl commands are added to support binary form statistics data
retrieval. KVM_STATS_GET_INFO, KVM_STATS_GET_NAMES, KVM_STATS_GET_DATA.
KVM_CAP_STATS_BINARY_FORM indicates the capability.

Signed-off-by: Jing Zhang <jingzhangos@google.com>
---
 virt/kvm/kvm_main.c | 115 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 115 insertions(+)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 383df23514b9..87dd62516c8b 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -3464,6 +3464,51 @@ static long kvm_vcpu_ioctl(struct file *filp,
 		r = kvm_arch_vcpu_ioctl_set_fpu(vcpu, fpu);
 		break;
 	}
+	case KVM_STATS_GET_INFO: {
+		struct kvm_stats_info stats_info;
+
+		r = -EFAULT;
+		stats_info.num_stats = VCPU_STAT_COUNT;
+		if (copy_to_user(argp, &stats_info, sizeof(stats_info)))
+			goto out;
+		r = 0;
+		break;
+	}
+	case KVM_STATS_GET_NAMES: {
+		struct kvm_stats_names stats_names;
+
+		r = -EFAULT;
+		if (copy_from_user(&stats_names, argp, sizeof(stats_names)))
+			goto out;
+		r = -EINVAL;
+		if (stats_names.size < VCPU_STAT_COUNT * KVM_STATS_NAME_LEN)
+			goto out;
+
+		r = -EFAULT;
+		if (copy_to_user(argp + sizeof(stats_names),
+				kvm_vcpu_stat_strings,
+				VCPU_STAT_COUNT * KVM_STATS_NAME_LEN))
+			goto out;
+		r = 0;
+		break;
+	}
+	case KVM_STATS_GET_DATA: {
+		struct kvm_stats_data stats_data;
+
+		r = -EFAULT;
+		if (copy_from_user(&stats_data, argp, sizeof(stats_data)))
+			goto out;
+		r = -EINVAL;
+		if (stats_data.size < sizeof(vcpu->stat))
+			goto out;
+
+		r = -EFAULT;
+		argp += sizeof(stats_data);
+		if (copy_to_user(argp, &vcpu->stat, sizeof(vcpu->stat)))
+			goto out;
+		r = 0;
+		break;
+	}
 	default:
 		r = kvm_arch_vcpu_ioctl(filp, ioctl, arg);
 	}
@@ -3695,6 +3740,7 @@ static long kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
 	case KVM_CAP_CHECK_EXTENSION_VM:
 	case KVM_CAP_ENABLE_CAP_VM:
 	case KVM_CAP_HALT_POLL:
+	case KVM_CAP_STATS_BINARY_FORM:
 		return 1;
 #ifdef CONFIG_KVM_MMIO
 	case KVM_CAP_COALESCED_MMIO:
@@ -3825,6 +3871,40 @@ static int kvm_vm_ioctl_enable_cap_generic(struct kvm *kvm,
 	}
 }
 
+static long kvm_vm_ioctl_stats_get_data(struct kvm *kvm, unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+	struct kvm_vcpu *vcpu;
+	struct kvm_stats_data stats_data;
+	u64 *data = NULL, *pdata;
+	int i, j, ret = 0;
+	size_t dsize = (VM_STAT_COUNT + VCPU_STAT_COUNT) * sizeof(*data);
+
+
+	if (copy_from_user(&stats_data, argp, sizeof(stats_data)))
+		return -EFAULT;
+	if (stats_data.size < dsize)
+		return -EINVAL;
+	data = kzalloc(dsize, GFP_KERNEL_ACCOUNT);
+	if (!data)
+		return -ENOMEM;
+
+	for (i = 0; i < VM_STAT_COUNT; i++)
+		*(data + i) = *((ulong *)&kvm->stat + i);
+
+	kvm_for_each_vcpu(j, vcpu, kvm) {
+		pdata = data + VM_STAT_COUNT;
+		for (i = 0; i < VCPU_STAT_COUNT; i++, pdata++)
+			*pdata += *((u64 *)&vcpu->stat + i);
+	}
+
+	if (copy_to_user(argp + sizeof(stats_data), data, dsize))
+		ret = -EFAULT;
+
+	kfree(data);
+	return ret;
+}
+
 static long kvm_vm_ioctl(struct file *filp,
 			   unsigned int ioctl, unsigned long arg)
 {
@@ -4001,6 +4081,41 @@ static long kvm_vm_ioctl(struct file *filp,
 		r = 0;
 		break;
 	}
+	case KVM_STATS_GET_INFO: {
+		struct kvm_stats_info stats_info;
+
+		r = -EFAULT;
+		stats_info.num_stats = VM_STAT_COUNT + VCPU_STAT_COUNT;
+		if (copy_to_user(argp, &stats_info, sizeof(stats_info)))
+			goto out;
+		r = 0;
+		break;
+	}
+	case KVM_STATS_GET_NAMES: {
+		struct kvm_stats_names stats_names;
+
+		r = -EFAULT;
+		if (copy_from_user(&stats_names, argp, sizeof(stats_names)))
+			goto out;
+		r = -EINVAL;
+		if (stats_names.size <
+			(VM_STAT_COUNT + VCPU_STAT_COUNT) * KVM_STATS_NAME_LEN)
+			goto out;
+		r = -EFAULT;
+		argp += sizeof(stats_names);
+		if (copy_to_user(argp, kvm_vm_stat_strings,
+				VM_STAT_COUNT * KVM_STATS_NAME_LEN))
+			goto out;
+		argp += VM_STAT_COUNT * KVM_STATS_NAME_LEN;
+		if (copy_to_user(argp, kvm_vcpu_stat_strings,
+				VCPU_STAT_COUNT * KVM_STATS_NAME_LEN))
+			goto out;
+		r = 0;
+		break;
+	}
+	case KVM_STATS_GET_DATA:
+		r =  kvm_vm_ioctl_stats_get_data(kvm, arg);
+		break;
 	case KVM_CHECK_EXTENSION:
 		r = kvm_vm_ioctl_check_extension_generic(kvm, arg);
 		break;
-- 
2.30.1.766.gb4fecdf3b7-goog