similar to: [PATCH 0/2] Trivial cleanups to virtualization tree

Big cleanup of LDT code. This code has very little type checking and is not frequently used, so I audited the code, added type checking and size optimizations to generate smaller assembly code. First, just introduce some small definitions that will be used later. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.14-zach-work/arch/i386/kernel/entry.S

Big cleanup of LDT code. This code has very little type checking and is not frequently used, so I audited the code, added type checking and size optimizations to generate smaller assembly code. First, just introduce some small definitions that will be used later. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.14-zach-work/arch/i386/kernel/entry.S

Add an acessor function to get a pointer to an LDT descriptor. Add one for the GDT too, while we are here, and a function to tell the difference. Turns out on some GCC versions, converting to char * and back gives better code output than gdt[seg >> 3]. Lets keep that trick in the header file so the C-code can be clean. Not used yet, but soon. Signed-off-by: Zachary Amsden

Add an acessor function to get a pointer to an LDT descriptor. Add one for the GDT too, while we are here, and a function to tell the difference. Turns out on some GCC versions, converting to char * and back gives better code output than gdt[seg >> 3]. Lets keep that trick in the header file so the C-code can be clean. Not used yet, but soon. Signed-off-by: Zachary Amsden

Big cleanup of LDT code. This code has very little type checking and is not frequently used, so I audited the code, added type checking and size optimizations to generate smaller assembly code. I changed the ldt count to be in pages, and converted the char * ldt into a desc_struct. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.14-zach-work/arch/i386/kernel/ldt.c

Big cleanup of LDT code. This code has very little type checking and is not frequently used, so I audited the code, added type checking and size optimizations to generate smaller assembly code. I changed the ldt count to be in pages, and converted the char * ldt into a desc_struct. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.14-zach-work/arch/i386/kernel/ldt.c

Clean up of patch for letting kernel run other than ring 0: a. Add some comments about the SEGMENT_IS_*_CODE() macros. b. Add a USER_RPL macro. (Code was comparing a value to a mask in some places and to the magic number 3 in other places.) c. Add macros for table indicator field and use them. d. Change the entry.S tests for LDT stack segment to use the macros. Signed-off-by: Chuck Ebbert

Clean up of patch for letting kernel run other than ring 0: a. Add some comments about the SEGMENT_IS_*_CODE() macros. b. Add a USER_RPL macro. (Code was comparing a value to a mask in some places and to the magic number 3 in other places.) c. Add macros for table indicator field and use them. d. Change the entry.S tests for LDT stack segment to use the macros. Signed-off-by: Chuck Ebbert

* zach@vmware.com (zach@vmware.com) wrote: > This code is quite dead. Release_thread is always guaranteed that the mm has > already been released, thus dead_task->mm will always be NULL. > > Signed-off-by: Zachary Amsden <zach@vmware.com> > Index: linux-2.6.13/arch/i386/kernel/process.c > =================================================================== > ---

* zach@vmware.com (zach@vmware.com) wrote: > This code is quite dead. Release_thread is always guaranteed that the mm has > already been released, thus dead_task->mm will always be NULL. > > Signed-off-by: Zachary Amsden <zach@vmware.com> > Index: linux-2.6.13/arch/i386/kernel/process.c > =================================================================== > ---

S.Çağlar Onur wrote: > 17 Eki 2006 Sal 01:21 tarihinde, S.Çağlar Onur şunları yazmıştı: > >> 17 Eki 2006 Sal 01:17 tarihinde, Zachary Amsden şunları yazmıştı: >> >>> My nasty quick patch might not apply - the only tree I've got is a very >>> hacked 2.6.18-rc6-mm1+local-patches thing, but the fix should be obvious >>> enough. >>>

S.Çağlar Onur wrote: > 17 Eki 2006 Sal 01:21 tarihinde, S.Çağlar Onur şunları yazmıştı: > >> 17 Eki 2006 Sal 01:17 tarihinde, Zachary Amsden şunları yazmıştı: >> >>> My nasty quick patch might not apply - the only tree I've got is a very >>> hacked 2.6.18-rc6-mm1+local-patches thing, but the fix should be obvious >>> enough. >>>

Three patches to clean up GDT access in Linux to make it friendly to virtualization environments. The basic problem is that the GDT must be write protected, which causes spurious overhead when the GDT lies on the same page as other data. This problem exists both for VMware and Xen; Xen actually requires page isolation, so we have implemented the most general and compatible solution. Patch 1

Three patches to clean up GDT access in Linux to make it friendly to virtualization environments. The basic problem is that the GDT must be write protected, which causes spurious overhead when the GDT lies on the same page as other data. This problem exists both for VMware and Xen; Xen actually requires page isolation, so we have implemented the most general and compatible solution. Patch 1

The macro set_wrprotect() should not be defined to have a value. Make it a do {} while(0) instead of ({}). Noticed by Chris Wright. Signed-off-by: Zachary Amsden <zach@vmware.com> Patch-subject: Make set_wrprotect() value safe Index: linux-2.6.13/include/asm-generic/pgtable.h =================================================================== ---

The macro set_wrprotect() should not be defined to have a value. Make it a do {} while(0) instead of ({}). Noticed by Chris Wright. Signed-off-by: Zachary Amsden <zach@vmware.com> Patch-subject: Make set_wrprotect() value safe Index: linux-2.6.13/include/asm-generic/pgtable.h =================================================================== ---

Patches to clean up descriptor access in Linux to make it friendly to virtualization environments. The basic problem is that the GDT must be write protected, which causes spurious overhead when the GDT lies on the same page as other data. This problem exists both for VMware and Xen; Xen actually requires page isolation, so we have implemented the most general and compatible solution. While

Patches to clean up descriptor access in Linux to make it friendly to virtualization environments. The basic problem is that the GDT must be write protected, which causes spurious overhead when the GDT lies on the same page as other data. This problem exists both for VMware and Xen; Xen actually requires page isolation, so we have implemented the most general and compatible solution. While

Ancient inline assembler that manipulates descriptor tables is unreadable and has no type checking. Doing this in C actually generates better code, saves code space, and improves readability. The fact that you must cast descriptors to (char *) for the inline assembler to work properly caused me no end of grief working on these patches. Note that GCC does not generate rotations to utilize

Ancient inline assembler that manipulates descriptor tables is unreadable and has no type checking. Doing this in C actually generates better code, saves code space, and improves readability. The fact that you must cast descriptors to (char *) for the inline assembler to work properly caused me no end of grief working on these patches. Note that GCC does not generate rotations to utilize