kvm2.c

#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <linux/kvm.h>
#include <errno.h>
#include <string.h>

int main(int argc, char* argv[])
{
	int kvm = open("/dev/kvm", O_RDWR);
	int vm = ioctl(kvm, KVM_CREATE_VM, 0);
	perror("CREATE_VM");

	ioctl(vm, KVM_SET_TSS_ADDR, 0xfffbd000);
	perror("KVM_SET_TSS_ADDR");

	int vcpu = ioctl(vm, KVM_CREATE_VCPU, 0);
	perror("CREATE_VCPU");
	
	void* ram_start;
	unsigned long ram_size = 1024L * 1024 * 16;
	posix_memalign(&ram_start, 65536, ram_size);

	struct kvm_userspace_memory_region mem;	
	mem.slot = 0;
	mem.guest_phys_addr = 0x0UL;
	mem.memory_size = ram_size;
	mem.userspace_addr = (unsigned long) ram_start;	

	ioctl(vm, KVM_SET_USER_MEMORY_REGION, &mem);
	perror("SET_USER_MEMORY_REGION");

	struct kvm_sregs sregs;
	ioctl(vcpu, KVM_GET_SREGS, &sregs);

	sregs.cs.selector = 0;
	sregs.ss.selector = 0;
	sregs.ds.selector = 0;
	sregs.es.selector = 0;
	sregs.gs.selector = 0;
	sregs.cs.base = 0;
	sregs.ss.base = 0;
	sregs.ds.base = 0;
	sregs.es.base = 0;
	sregs.fs.base = 0;
	sregs.gs.base = 0;
	sregs.cr0 |= 0x1;

	#define GDTLOC (0xF00Baa)	

	*(unsigned long*) (ram_start+GDTLOC) = 0x00000000000000000;
	*(unsigned long*) (ram_start+GDTLOC+8) = 0x00cf9a000000ffff;
	*(unsigned long*) (ram_start+GDTLOC+16) = 0x00cf92000000ffff;
	
	sregs.gdt.base = GDTLOC;
	sregs.gdt.limit = 32;
	sregs.idt.base = 0;
	sregs.idt.limit = 0;
	
	sregs.cs.selector = 8;
	sregs.ss.selector = 16;
	sregs.ds.selector = 16;
	sregs.es.selector = 16;

	sregs.cs.g = 1;
	sregs.ss.g = 1;
	sregs.ds.g = 1;
	sregs.es.g = 1;

	sregs.cs.db = 1;
	sregs.ss.db = 1;
	sregs.ds.db = 1;
	sregs.es.db = 1;

	sregs.cs.limit =0xffffffff;
	sregs.ss.limit =0xffffffff;
	sregs.ds.limit =0xffffffff;
	sregs.es.limit =0xffffffff;

	ioctl(vcpu, KVM_SET_SREGS, &sregs);
	perror("KVM_SER_SREGS");
	
	struct kvm_regs regs;	
	regs = (struct kvm_regs) {
	        .rflags         = 0x0000000000000002ULL,
        	.rip            = 0x0000,
	        .rsp            = ram_size,
        	.rbp            = ram_size - 0x500, //0x8000,
	};

	ioctl(vcpu, KVM_SET_REGS, &regs);
	perror("KVM_SET_REGS");

	ioctl(vcpu, KVM_RUN, 0);
	perror("KVM_RUN");
}