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Diffstat (limited to 'qemu-doc.texi')
| -rw-r--r-- | qemu-doc.texi | 35 |
1 files changed, 30 insertions, 5 deletions
diff --git a/qemu-doc.texi b/qemu-doc.texi index c29dc22ad3..2c7249ff95 100644 --- a/qemu-doc.texi +++ b/qemu-doc.texi @@ -36,6 +36,8 @@ User space LDT and GDT are emulated. VM86 mode is also supported @item Accurate signal handling by remapping host signals to virtual x86 signals. +@item QEMU can emulate itself on x86 (experimental). + @item The virtual x86 CPU is a library (@code{libqemu}) which can be used in other projects. @@ -50,9 +52,7 @@ Current QEMU Limitations: @item Not all x86 exceptions are precise (yet). [Very few programs need that]. -@item Not self virtualizable (yet). [You cannot launch qemu with qemu on the same CPU]. - -@item No support for self modifying code (yet). [Very few programs need that, a notable exception is QEMU itself !]. +@item No support for self-modifying code (yet). [Very few programs need that, a notable exception is QEMU itself !]. @item No SSE/MMX support (yet). @@ -88,9 +88,14 @@ qemu -L / /bin/ls @code{-L /} tells that the x86 dynamic linker must be searched with a @file{/} prefix. +@item Since QEMU is also a linux process, you can launch qemu with qemu: + +@example +qemu -L / qemu -L / /bin/ls +@end example @item On non x86 CPUs, you need first to download at least an x86 glibc -(@file{qemu-i386-glibc21.tar.gz} on the QEMU web page). Ensure that +(@file{qemu-XXX-i386-glibc21.tar.gz} on the QEMU web page). Ensure that @code{LD_LIBRARY_PATH} is not set: @example @@ -107,6 +112,11 @@ QEMU is automatically launched by the Linux kernel when you try to launch x86 executables. It requires the @code{binfmt_misc} module in the Linux kernel. +@item The x86 version of QEMU is also included. You can try weird things such as: +@example +qemu /usr/local/qemu-i386/bin/qemu-i386 /usr/local/qemu-i386/bin/ls-i386 +@end example + @end itemize @section Wine launch (Currently only tested when emulating x86 on x86) @@ -122,7 +132,7 @@ qemu /usr/local/qemu-i386/bin/ls-i386 @end example @item Download the binary x86 Wine install -(@file{qemu-i386-wine.tar.gz} on the QEMU web page). +(@file{qemu-XXX-i386-wine.tar.gz} on the QEMU web page). @item Configure Wine on your account. Look at the provided script @file{/usr/local/qemu-i386/bin/wine-conf.sh}. Your previous @@ -302,6 +312,21 @@ thread. The virtual x86 CPU atomic operations are emulated with a global lock so that their semantic is preserved. +@section Self-virtualization + +QEMU was conceived so that ultimately it can emulate itself. Althought +it is not very useful, it is an important test to show the power of the +emulator. + +Achieving self-virtualization is not easy because there may be address +space conflicts. QEMU solves this problem by being an ELF shared object +as the ld-linux.so ELF interpreter. That way, it can be relocated at +load time. + +Since self-modifying code is not supported yet, QEMU cannot self +virtualize itself in case of translation cache flush. This limitation +will be suppressed soon. + @section Bibliography @table @asis |