KVM: Use a shared page for kernel/user communication when runing a vcpu

Instead of passing a 'struct kvm_run' back and forth between the kernel and
userspace, allocate a page and allow the user to mmap() it.  This reduces
needless copying and makes the interface expandable by providing lots of
free space.

Signed-off-by: Avi Kivity <avi@qumranet.com>
This commit is contained in:
Avi Kivity 2007-02-22 12:58:31 +02:00
parent 1ea252afcd
commit 9a2bb7f486
3 changed files with 44 additions and 17 deletions

View file

@ -11,7 +11,7 @@
#include <asm/types.h>
#include <linux/ioctl.h>
#define KVM_API_VERSION 4
#define KVM_API_VERSION 5
/*
* Architectural interrupt line count, and the size of the bitmap needed
@ -49,7 +49,7 @@ enum kvm_exit_reason {
KVM_EXIT_SHUTDOWN = 8,
};
/* for KVM_RUN */
/* for KVM_RUN, returned by mmap(vcpu_fd, offset=0) */
struct kvm_run {
/* in */
__u32 emulated; /* skip current instruction */
@ -233,7 +233,7 @@ struct kvm_dirty_log {
/*
* ioctls for vcpu fds
*/
#define KVM_RUN _IOWR(KVMIO, 2, struct kvm_run)
#define KVM_RUN _IO(KVMIO, 16)
#define KVM_GET_REGS _IOR(KVMIO, 3, struct kvm_regs)
#define KVM_SET_REGS _IOW(KVMIO, 4, struct kvm_regs)
#define KVM_GET_SREGS _IOR(KVMIO, 5, struct kvm_sregs)