From: Pekka Enberg <penberg@kernel.org>
Date: Fri, 30 Sep 2011 15:53:48 +0000 (+0300)
Subject: kvm tools, bios: Fix BIOS to kernel memory copy
X-Git-Tag: next-20111025~3^2~6
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=15a0bb5ccae93c061c0345a6ce1fe6157628663c;p=karo-tx-linux.git

kvm tools, bios: Fix BIOS to kernel memory copy

This patch implements memcpy16() function that copies memory areas in 16-bit
real mode and converts bios/int10.c to use it instead of relying on GCC struct
memcpy to do the right thing.

Acked-by: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Asias He <asias.hejun@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
---

diff --git a/tools/kvm/Makefile b/tools/kvm/Makefile
index 3939c1164294..8387e2f9dbc1 100644
--- a/tools/kvm/Makefile
+++ b/tools/kvm/Makefile
@@ -219,6 +219,8 @@ BIOS_CFLAGS += -mregparm=3
 bios.o: bios/bios.bin bios/bios-rom.h
 
 bios/bios.bin.elf: bios/entry.S bios/e820.c bios/int10.c bios/int15.c bios/rom.ld.S
+	$(E) "  CC       bios/memcpy.o"
+	$(Q) $(CC) -include code16gcc.h $(CFLAGS) $(BIOS_CFLAGS) -c -s bios/memcpy.c -o bios/memcpy.o
 	$(E) "  CC       bios/e820.o"
 	$(Q) $(CC) -include code16gcc.h $(CFLAGS) $(BIOS_CFLAGS) -c -s bios/e820.c -o bios/e820.o
 	$(E) "  CC       bios/int10.o"
@@ -228,7 +230,7 @@ bios/bios.bin.elf: bios/entry.S bios/e820.c bios/int10.c bios/int15.c bios/rom.l
 	$(E) "  CC       bios/entry.o"
 	$(Q) $(CC) $(CFLAGS) $(BIOS_CFLAGS) -c -s bios/entry.S -o bios/entry.o
 	$(E) "  LD      " $@
-	$(Q) ld -T bios/rom.ld.S -o bios/bios.bin.elf bios/entry.o bios/e820.o bios/int10.o bios/int15.o
+	$(Q) ld -T bios/rom.ld.S -o bios/bios.bin.elf bios/memcpy.o bios/entry.o bios/e820.o bios/int10.o bios/int15.o
 
 bios/bios.bin: bios/bios.bin.elf
 	$(E) "  OBJCOPY " $@
diff --git a/tools/kvm/bios/entry.S b/tools/kvm/bios/entry.S
index 2ee21a9116d6..85056e9816c4 100644
--- a/tools/kvm/bios/entry.S
+++ b/tools/kvm/bios/entry.S
@@ -16,6 +16,7 @@
 .macro SAVE_BIOSREGS
 	pushl	%fs
 	pushl	%es
+	pushl	%ds
 	pushl	%edi
 	pushl	%esi
 	pushl	%ebp
@@ -35,6 +36,7 @@
 	popl	%ebp
 	popl	%esi
 	popl	%edi
+	popl	%ds
 	popl	%es
 	popl	%fs
 .endm
diff --git a/tools/kvm/bios/int10.c b/tools/kvm/bios/int10.c
index 22da9fa0f928..6387ca8b15eb 100644
--- a/tools/kvm/bios/int10.c
+++ b/tools/kvm/bios/int10.c
@@ -2,6 +2,9 @@
 #include "kvm/bios.h"
 #include "kvm/util.h"
 #include "kvm/vesa.h"
+
+#include "bios/memcpy.h"
+
 #include <stdint.h>
 
 #define VESA_MAGIC ('V' + ('E' << 8) + ('S' << 16) + ('A' << 24))
@@ -99,18 +102,21 @@ static void vbe_get_mode(struct biosregs *args)
 
 static void vbe_get_info(struct biosregs *args)
 {
-	struct vesa_general_info *info = (struct vesa_general_info *) args->edi;
+	struct vesa_general_info *infop = (struct vesa_general_info *) args->edi;
+	struct vesa_general_info info;
 
-	*info = (struct vesa_general_info) {
+	info = (struct vesa_general_info) {
 		.signature		= VESA_MAGIC,
 		.version		= 0x102,
-		.vendor_string		= &info->oem_string,
+		.vendor_string		= &infop->oem_string,
 		.capabilities		= 0x10,
-		.video_mode_ptr		= &info->modes,
+		.video_mode_ptr		= &infop->modes,
 		.total_memory		= (4 * VESA_WIDTH * VESA_HEIGHT) / 0x10000,
 		.oem_string		= "KVM VESA",
 		.modes			= { 0x0112, 0xffff },
 	};
+
+	memcpy16(args->es, infop, args->ds, &info, sizeof(info));
 }
 
 #define VBE_STATUS_OK		0x004F
diff --git a/tools/kvm/bios/memcpy.c b/tools/kvm/bios/memcpy.c
new file mode 100644
index 000000000000..40b9b65fa9e4
--- /dev/null
+++ b/tools/kvm/bios/memcpy.c
@@ -0,0 +1,23 @@
+#include "bios/memcpy.h"
+
+/*
+ *  Copy memory area in 16-bit real mode.
+ */
+void memcpy16(u16 dst_seg, void *dst, u16 src_seg, const void *src, size_t len)
+{
+	__asm__ __volatile__ (
+		"pushw	%%ds				\n"
+		"pushw	%%es				\n"
+		"movw	%[src_seg], %%ds		\n"
+		"movw	%[dst_seg], %%es		\n"
+		"rep movsb %%ds:(%%si), %%es:(%%di)	\n"
+		"popw	%%es				\n"
+		"popw	%%ds				\n"
+		:
+		: "S"(src),
+		  "D"(dst),
+		  "c"(len),
+		  [src_seg] "r"(src_seg),
+		  [dst_seg] "r"(dst_seg)
+		: "cc", "memory");
+}
diff --git a/tools/kvm/include/bios/memcpy.h b/tools/kvm/include/bios/memcpy.h
new file mode 100644
index 000000000000..e0210449e80f
--- /dev/null
+++ b/tools/kvm/include/bios/memcpy.h
@@ -0,0 +1,9 @@
+#ifndef KVM_BIOS_MEMCPY_H
+#define KVM_BIOS_MEMCPY_H
+
+#include <linux/types.h>
+#include <stddef.h>
+
+void memcpy16(u16 dst_seg, void *dst, u16 src_seg, const void *src, size_t len);
+
+#endif /* KVM_BIOS_MEMCPY_H */
diff --git a/tools/kvm/include/kvm/bios.h b/tools/kvm/include/kvm/bios.h
index 469576ecaaa4..39cc972e9cc3 100644
--- a/tools/kvm/include/kvm/bios.h
+++ b/tools/kvm/include/kvm/bios.h
@@ -69,6 +69,7 @@ struct biosregs {
 	u32			ebp;
 	u32			esi;
 	u32			edi;
+	u32			ds;
 	u32			es;
 	u32			fs;
 	u32			eip;