[Qemu-devel] Re: KQEMU code organization

[Jan Kiszka <jan.kiszka@web.de>]

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Jan Kiszka wrote:
> Fabrice Bellard wrote:
>> Jan Kiszka wrote:
>>> Fabrice Bellard wrote:
>>>> Jan Kiszka wrote:
>>>>> Hi,
>>>>>
>>>>> is there a technical reason why the kqemu kernel module is built out of
>>>>> a binary blob (monitor-image.bin->monitor-image.h)? Does this simply
>>>>> date back to the time when wrapper and core were distributed under
>>>>> different licenses?
>>>> This is a technical reason: the "blob" is run in an address space
>>>> different from the host kernel.
>>> Well, easy to claim, I know, but I don't think this is a hard reason.
>>> However, as overcoming genmon and genoffset may require quite some
>>> refactoring, I'm not sure if it's worth it.
>> I may change the monitor blob format to ELF to allow relocation, but the
>> idea stays the same, and I don't think you can do it another way...
> 
> I agree (from my current knowledge of the problem) that the monitor
> remains "foreign" code to the kernel module. But at least the
> repackaging into a c-structure should be unnecessary.
> 
> The offset generation can be skipped if the assembly files are converted
> into inline assembly. Might be tricky in some cases, but I see no
> show-stopper yet.
> 
> The give it a tiny start, I will look if I can unify the build process
> for all "true" kernel components. That is what currently breaks the
> debugability of the driver frame (up to kernel2monitor), and which also
> causes a kbuild warning. Likely harmless ATM, but it is fragile on
> long-term.

Here we go. Still not nice (I would put all monitor code in its own
directory, moving those few host kernel bits into the top-level dir),
but at least much cleaner from kbuild's POV.

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
---
 Makefile |   15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

Index: b/Makefile
===================================================================
--- a/Makefile
+++ b/Makefile
@@ -17,7 +17,7 @@ ifdef CONFIG_KBUILD26
 all: kqemu.ko
 
 kqemu.ko:
-	make -C common all
+	make -C common monitor-image.h
 	make -C $(KERNEL_PATH) M=`pwd` modules
 
 else
@@ -38,7 +38,8 @@ endif # !CONFIG_WIN32
 
 clean:
 	$(MAKE) -C common clean
-	rm -f kqemu.ko *.o *~
+	rm -rf kqemu.ko *.o *~ .kqemu* Module.* modules.order kqemu.mod.c .tmp_versions \
+               common/.kernel* common/*/.kernel*
 
 FILES=configure Makefile README Changelog LICENSE COPYING \
       install.sh kqemu-linux.c kqemu.h \
@@ -89,10 +90,10 @@ kqemu.o: $(kqemu-objs)
 else
 # called from 2.6 kernel kbuild
 
-obj-m:= kqemu.o
-kqemu-objs:= kqemu-linux.o kqemu-mod.o
+EXTRA_AFLAGS=-I $(PWD)/common
+EXTRA_CFLAGS=-I $(PWD)
 
-$(obj)/kqemu-mod.o: $(src)/kqemu-mod-$(ARCH).o
-	cp $< $@
+obj-m:= kqemu.o
+kqemu-objs:= kqemu-linux.o common/kernel.o common/$(ARCH)/kernel_asm.o
 endif
 endif # PATCHLEVEL


BTW, there is more trouble ahead for kqemu. This is what I get booting a 
x86-64 OpenSuse 10.3 image on a 64-bit platform:

RAX=ffff810001008220 RBX=ffff81002f88a160 RCX=0000000000000036 RDX=0000000000000000
RSI=ffffe20000065aa0 RDI=ffff81002f88a164 RBP=ffff81002df99e68 RSP=ffff81002df99e68
R8 =0000000000000000 R9 =0000000000000000 R10=ffff81002df99db8 R11=0000000000010246
R12=ffff81002f88a164 R13=0000000000000004 R14=ffff81002f4a6b10 R15=ffff81002df99f58
RIP=ffffffff80447515 RFL=00010246 [---Z-P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0000 0000000000000000 00000000 00000000
CS =0010 0000000000000000 ffffffff 00a09b00
SS =0000 0000000000000000 ffffffff 00c09300
DS =0000 0000000000000000 00000000 00000000
FS =0000 0000000000000000 00000000 00000000
GS =0000 ffffffff8059b000 00000000 00000000
LDT=0000 0000000000000000 00000000 00008000
TR =0040 ffff81000101c280 00002087 00008900
GDT=     ffffffff8061e000 00000080
IDT=     ffffffff8067f000 00000fff
CR0=8005003b CR2=00007fff4183bf70 CR3=000000002e8a7000 CR4=000006a0
Unsupported return value: 0xffffffff

Kernel log says

  kqemu: aborting: Unexpected exception 0x0d in monitor space
  err=0000 CS:EIP=f180:00000000f0001f6f SS:SP=0000:00000000f00c6e20

with the official kqemu and, interestingly,

  kqemu: aborting: mon_get_ptel_l3() failed

with Ben's repos.

Jan


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