Enable CR4.VME to improve the performance of vm86 emulation.

PATCH New Arun Sharma 1 participant 1 message Jul 13, 2005

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Arun Sharma

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2005-07-13 23:14 UTC #0 lore raw

PATCH 1/1 Enable CR4.VME to improve the performance of vm86 emulation.

Enable CR4.VME to improve the performance of vm86 emulation.

Setting this bit eliminates the calls to the vm86 monitor to handle interrupts and exceptions that occur while executing programs in vm86 mode.

Signed-off-by Asit Mallick <[email protected]>

Signed-off-by Arun Sharma <[email protected]>

tools/firmware/vmxassist/Makefile +1 -1

diff -r ae5dbce3f530 -r 3e44f5b38645 tools/firmware/vmxassist/Makefile
@@ -24,7 +24,7 @@
 # The emulator code lives in ROM space
 TEXTADDR=0x000D0000
 
-DEFINES=-DDEBUG -DTEXTADDR=${TEXTADDR} -D_ACPI_
+DEFINES=-DDEBUG -DENABLE_VME -DTEXTADDR=${TEXTADDR}
 XENINC=-I$(XEN_ROOT)/xen/include -I$(XEN_ROOT)/tools/libxc
 #DEFINES=-DDEBUG -DTEST -DTEXTADDR=${TEXTADDR}
 #XENINC=-I/home/leendert/xen/xeno-unstable.bk/xen/include

tools/firmware/vmxassist/machine.h +17 ~~-13~~

diff -r ae5dbce3f530 -r 3e44f5b38645 tools/firmware/vmxassist/machine.h
@@ -40,7 +40,8 @@
 #define EFLAGS_TF	(1 << 8)
 #define EFLAGS_IF	(1 << 9)
 #define EFLAGS_DF	(1 << 10)
-#define EFLAGS_VM	(1 << 17)
+#define EFLAGS_IOPL (3 << 12)
+#define EFLAGS_VM	((1 << 17) | EFLAGS_IOPL)
 #define EFLAGS_VIF	(1 << 19)
 #define EFLAGS_VIP	(1 << 20)

@@ -109,6 +110,9 @@
 	unsigned short	_5;
 	unsigned short	_6;
 	unsigned short	iomap_base;
+#ifdef	ENABLE_VME
+	unsigned long	int_redir[8];
+#endif
 	unsigned char	iomap[8192];
 };

@@ -177,20 +181,20 @@
         return rv;
 }
 
+static inline void
+set_cr3(unsigned addr)
+{
+        __asm__ __volatile__("movl %0, %%cr3" : /* no outputs */ : "r"(addr));
+}
+
+static inline void
+set_cr4(unsigned value)
+{
+	__asm__ __volatile__("movl %0, %%cr4" : /* no outputs */ : "r"(value));
+}
+
 #ifdef TEST
 static inline void
-set_cr3(unsigned addr)
-{
-        __asm__ __volatile__("movl %0, %%cr3" : /* no outputs */ : "r"(addr));
-}
-
-static inline void
-set_cr4(unsigned value)
-{
-	__asm__ __volatile__("movl %0, %%cr4" : /* no outputs */ : "r"(value));
-}
-
-static inline void
 breakpoint(void)
 {
 	outw(0x8A00, 0x8AE0);

tools/firmware/vmxassist/setup.c +4 -1

diff -r ae5dbce3f530 -r 3e44f5b38645 tools/firmware/vmxassist/setup.c
@@ -121,7 +121,7 @@
 setup_gdt(void)
 {
 	/* setup task state segment */
-	memset(&tss, 0, sizeof(0));
+	memset(&tss, 0, sizeof(tss));
 	tss.ss0 = DATA_SELECTOR;
 	tss.esp0 = (unsigned) stack_top - 4*4;
 	tss.iomap_base = offsetof(struct tss, iomap);

@@ -353,6 +353,9 @@
 #endif
 	setup_gdt();
 	setup_idt();
+#ifdef	ENABLE_VME
+	set_cr4(get_cr4() | CR4_VME); 
+#endif
 	setup_ctx();
 	setup_pic();
 	start_bios();