From 102d8325a1d2f266d3d0a03fdde948544e72c12d Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 19 Feb 2007 14:37:47 +0200 Subject: 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 Signed-off-by: Avi Kivity --- include/linux/kvm_para.h | 55 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) create mode 100644 include/linux/kvm_para.h (limited to 'include/linux/kvm_para.h') diff --git a/include/linux/kvm_para.h b/include/linux/kvm_para.h new file mode 100644 index 000000000000..74be5c1002ec --- /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 -- cgit v1.2.2