First attempt at making kvm86 MP safe, place mutex lock around calls

to kvm86_bioscall at IPL_IPI this might be incorrect, seems to fix
some issues with vt switching, however X still bombs on the second attempt with
disappointing frequency.
ok deraadt@

1 files changed, 9 insertions, 2 deletions

diff --git a/sys/arch/i386/i386/kvm86.c b/sys/arch/i386/i386/kvm86.c
index 7cf1df582a0..2ccea3bcd8b 100644
--- a/sys/arch/i386/i386/kvm86.c
+++ b/sys/arch/i386/i386/kvm86.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kvm86.c,v 1.1 2006/06/13 03:01:04 gwk Exp $ */
+/* $OpenBSD: kvm86.c,v 1.2 2006/11/27 16:00:19 gwk Exp $ */
 /* $NetBSD: kvm86.c,v 1.10 2005/12/26 19:23:59 perry Exp $ */
 /*
  * Copyright (c) 2002
@@ -32,6 +32,8 @@
 #include <sys/proc.h>
 #include <sys/user.h>
 #include <sys/malloc.h>
+#include <sys/mutex.h>
+#include <sys/simplelock.h>
 #include <uvm/uvm_extern.h>
 #include <uvm/uvm.h>
 #include <machine/pcb.h>
@@ -72,6 +74,8 @@ void *bioscallscratchpage;
 /* a virtual page to map in vm86 memory temporarily */
 vaddr_t bioscalltmpva;
 
+struct mutex kvm86_mp_mutex;
+
 #define KVM86_IOPL3 /* not strictly necessary, saves a lot of traps */
 
 void
@@ -122,6 +126,7 @@ kvm86_init()
 	kvm86_map(vmd, pa, BIOSCALLSCRATCHPAGE_VMVA);
 	bioscallvmd = vmd;
 	bioscalltmpva = uvm_km_alloc(kernel_map, PAGE_SIZE);
+	mtx_init(&kvm86_mp_mutex, IPL_IPI);
 }
 
 /*
@@ -260,8 +265,10 @@ kvm86_simplecall(int no, struct kvm86regs *regs)
 	tf.tf_edi = regs->edi;
 	tf.tf_vm86_es = regs->es;
 	
+	mtx_enter(&kvm86_mp_mutex);	
 	res = kvm86_bioscall(no, &tf);
-	
+	mtx_leave(&kvm86_mp_mutex);
+
 	regs->eax = tf.tf_eax;
 	regs->ebx = tf.tf_ebx;
 	regs->ecx = tf.tf_ecx;