1 files changed, 102 insertions, 0 deletions
diff --git a/drivers/kvm/x86.c b/drivers/kvm/x86.c
new file mode 100644
index 000000000000..437902cf178d
--- /dev/null
+++ b/drivers/kvm/x86.c
@@ -0,0 +1,102 @@
+/*
+ * Kernel-based Virtual Machine driver for Linux
+ *
+ * derived from drivers/kvm/kvm_main.c
+ *
+ * Copyright (C) 2006 Qumranet, Inc.
+ *
+ * Authors:
+ *   Avi Kivity   <avi@qumranet.com>
+ *   Yaniv Kamay  <yaniv@qumranet.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+
+#include "x86.h"
+
+#include <asm/uaccess.h>
+
+/*
+ * List of msr numbers which we expose to userspace through KVM_GET_MSRS
+ * and KVM_SET_MSRS, and KVM_GET_MSR_INDEX_LIST.
+ *
+ * This list is modified at module load time to reflect the
+ * capabilities of the host cpu.
+ */
+static u32 msrs_to_save[] = {
+	MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP,
+	MSR_K6_STAR,
+#ifdef CONFIG_X86_64
+	MSR_CSTAR, MSR_KERNEL_GS_BASE, MSR_SYSCALL_MASK, MSR_LSTAR,
+#endif
+	MSR_IA32_TIME_STAMP_COUNTER,
+};
+
+static unsigned num_msrs_to_save;
+
+static u32 emulated_msrs[] = {
+	MSR_IA32_MISC_ENABLE,
+};
+
+long kvm_arch_dev_ioctl(struct file *filp,
+			unsigned int ioctl, unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+	long r;
+
+	switch (ioctl) {
+	case KVM_GET_MSR_INDEX_LIST: {
+		struct kvm_msr_list __user *user_msr_list = argp;
+		struct kvm_msr_list msr_list;
+		unsigned n;
+
+		r = -EFAULT;
+		if (copy_from_user(&msr_list, user_msr_list, sizeof msr_list))
+			goto out;
+		n = msr_list.nmsrs;
+		msr_list.nmsrs = num_msrs_to_save + ARRAY_SIZE(emulated_msrs);
+		if (copy_to_user(user_msr_list, &msr_list, sizeof msr_list))
+			goto out;
+		r = -E2BIG;
+		if (n < num_msrs_to_save)
+			goto out;
+		r = -EFAULT;
+		if (copy_to_user(user_msr_list->indices, &msrs_to_save,
+				 num_msrs_to_save * sizeof(u32)))
+			goto out;
+		if (copy_to_user(user_msr_list->indices
+				 + num_msrs_to_save * sizeof(u32),
+				 &emulated_msrs,
+				 ARRAY_SIZE(emulated_msrs) * sizeof(u32)))
+			goto out;
+		r = 0;
+		break;
+	}
+	default:
+		r = -EINVAL;
+	}
+out:
+	return r;
+}
+
+static __init void kvm_init_msr_list(void)
+{
+	u32 dummy[2];
+	unsigned i, j;
+
+	for (i = j = 0; i < ARRAY_SIZE(msrs_to_save); i++) {
+		if (rdmsr_safe(msrs_to_save[i], &dummy[0], &dummy[1]) < 0)
+			continue;
+		if (j < i)
+			msrs_to_save[j] = msrs_to_save[i];
+		j++;
+	}
+	num_msrs_to_save = j;
+}
+
+__init void kvm_arch_init(void)
+{
+	kvm_init_msr_list();
+}