[status report #1] BHyVe BIOS emulation to boot legacy systems

[Takuya ASADA]

* project summary
The project goal is to support BIOS emulation on BHyVe, enabling boot
from disk image.
I going to focus booting FreeBSD/amd64 from disk image on this GSoC,
but final goal is to make BHyVe able to support more guest OSes.

* preparation to develop BHyVe
Before try to join BHyVe development, I read the source code and think
what BHyVe doing on FreeBSD host system, and made presentations about
it, discussed in some small conferences.

Here're slides(Unfortunately, it's in Japanese):
- http://www.slideshare.net/AsadaTakuya/bhyve
- http://www.slideshare.net/syuu1228/bhyve-12636280
- http://www.slideshare.net/syuu1228/bhyve-internals-13082679

Result of this activity, I could get some members who have interest to
play with BHyVe, we probably going to held small Hackathon in next
month.

* trap VMCALL instruction
test code worked fine.

## patch for guest kernel ##
--- /usr/src-bhyve/sys/amd64/amd64/locore.S	2012-01-03 12:27:06.000000000 +0900
+++ /home/syuu/9.0-bhyve/sys/amd64/amd64/locore.S	2012-05-30
09:05:33.000000000 +0900
@@ -77,7 +77,9 @@
 	xorl	%ebp, %ebp

 	call	hammer_time		/* set up cpu for unix operation */
-	movq	%rax,%rsp		/* set up kstack for mi_startup() */
+
+	.byte	0xf,0x1,0xc1
+
 	call	mi_startup		/* autoconfiguration, mountroot etc */
 0:	hlt
 	jmp	0b


## patch for host ##

Index: usr.sbin/bhyve/fbsdrun.c
===================================================================
--- usr.sbin/bhyve/fbsdrun.c	(revision 236685)
+++ usr.sbin/bhyve/fbsdrun.c	(working copy)
@@ -429,6 +429,15 @@
 	return (VMEXIT_CONTINUE);
 }

+static int
+vmexit_vmcall(struct vmctx *ctx, struct vm_exit *vmexit, int *pvcpu)
+{
+	printf("VMCALL handled\n");
+	exit(1);
+
+	return (VMEXIT_RESTART);
+}
+
 static void
 sigalrm(int sig)
 {
@@ -469,7 +478,8 @@
 	[VM_EXITCODE_RDMSR]  = vmexit_rdmsr,
 	[VM_EXITCODE_WRMSR]  = vmexit_wrmsr,
 	[VM_EXITCODE_MTRAP]  = vmexit_mtrap,
-	[VM_EXITCODE_PAGING] = vmexit_paging
+	[VM_EXITCODE_PAGING] = vmexit_paging,
+	[VM_EXITCODE_VMCALL] = vmexit_vmcall,
 };

 static void
Index: sys/amd64/include/vmm.h
===================================================================
--- sys/amd64/include/vmm.h	(revision 236685)
+++ sys/amd64/include/vmm.h	(working copy)
@@ -228,6 +228,7 @@
 	VM_EXITCODE_MTRAP,
 	VM_EXITCODE_PAUSE,
 	VM_EXITCODE_PAGING,
+	VM_EXITCODE_VMCALL,
 	VM_EXITCODE_MAX
 };

Index: sys/amd64/vmm/intel/vmx.c
===================================================================
--- sys/amd64/vmm/intel/vmx.c	(revision 236685)
+++ sys/amd64/vmm/intel/vmx.c	(working copy)
@@ -1189,6 +1189,9 @@
 		vmexit->exitcode = VM_EXITCODE_PAGING;
 		vmexit->u.paging.cr3 = vmcs_guest_cr3();
 		break;
+	case EXIT_REASON_VMCALL:
+		vmexit->exitcode = VM_EXITCODE_VMCALL;
+		break;
 	default:
 		break;
 	}