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authorIngo Molnar <mingo@elte.hu>2007-02-19 14:37:47 +0200
committerAvi Kivity <avi@qumranet.com>2007-03-04 11:12:40 +0200
commit102d8325a1d2f266d3d0a03fdde948544e72c12d (patch)
tree21024c8b9b2b702c79200343e26f14f075da0479 /include/linux
parent5972e9535e94bf875eb8eab8a667ba04c7583874 (diff)
KVM: add MSR based hypercall API
This adds a special MSR based hypercall API to KVM. This is to be used by paravirtual kernels and virtual drivers. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/kvm_para.h55
1 files changed, 55 insertions, 0 deletions
diff --git a/include/linux/kvm_para.h b/include/linux/kvm_para.h
new file mode 100644
index 00000000000..74be5c1002e
--- /dev/null
+++ b/include/linux/kvm_para.h
@@ -0,0 +1,55 @@
+#ifndef __LINUX_KVM_PARA_H
+#define __LINUX_KVM_PARA_H
+
+/*
+ * Guest OS interface for KVM paravirtualization
+ *
+ * Note: this interface is totally experimental, and is certain to change
+ * as we make progress.
+ */
+
+/*
+ * Per-VCPU descriptor area shared between guest and host. Writable to
+ * both guest and host. Registered with the host by the guest when
+ * a guest acknowledges paravirtual mode.
+ *
+ * NOTE: all addresses are guest-physical addresses (gpa), to make it
+ * easier for the hypervisor to map between the various addresses.
+ */
+struct kvm_vcpu_para_state {
+ /*
+ * API version information for compatibility. If there's any support
+ * mismatch (too old host trying to execute too new guest) then
+ * the host will deny entry into paravirtual mode. Any other
+ * combination (new host + old guest and new host + new guest)
+ * is supposed to work - new host versions will support all old
+ * guest API versions.
+ */
+ u32 guest_version;
+ u32 host_version;
+ u32 size;
+ u32 ret;
+
+ /*
+ * The address of the vm exit instruction (VMCALL or VMMCALL),
+ * which the host will patch according to the CPU model the
+ * VM runs on:
+ */
+ u64 hypercall_gpa;
+
+} __attribute__ ((aligned(PAGE_SIZE)));
+
+#define KVM_PARA_API_VERSION 1
+
+/*
+ * This is used for an RDMSR's ECX parameter to probe for a KVM host.
+ * Hopefully no CPU vendor will use up this number. This is placed well
+ * out of way of the typical space occupied by CPU vendors' MSR indices,
+ * and we think (or at least hope) it wont be occupied in the future
+ * either.
+ */
+#define MSR_KVM_API_MAGIC 0x87655678
+
+#define KVM_EINVAL 1
+
+#endif