similar to: [PATCH 2/6] i386 virtualization - Remove some dead debugging code

Remove the "temporary debugging check" which has managed to live for quite some time, and is clearly unneeded. The mm can never be live at this point, so clearly checking the LDT in the mm->context is redundant as well. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.14-zach-work/arch/i386/kernel/process.c

Remove the "temporary debugging check" which has managed to live for quite some time, and is clearly unneeded. The mm can never be live at this point, so clearly checking the LDT in the mm->context is redundant as well. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.14-zach-work/arch/i386/kernel/process.c

* zach@vmware.com (zach@vmware.com) wrote: > Make the LDT a desc_struct pointer, since this is what it actually is. I like that plan. > There is code which relies on the fact that LDTs are allocated in page > chunks, and it is both cleaner and more convenient to keep the rather > poorly named "size" variable from the LDT in terms of LDT pages. I noticed it's replaced

* zach@vmware.com (zach@vmware.com) wrote: > Make the LDT a desc_struct pointer, since this is what it actually is. I like that plan. > There is code which relies on the fact that LDTs are allocated in page > chunks, and it is both cleaner and more convenient to keep the rather > poorly named "size" variable from the LDT in terms of LDT pages. I noticed it's replaced

Introduce a write acessor for updating the current LDT. This is required for hypervisors like Xen that do not allow LDT pages to be directly written. Testing - here's a fun little LDT test that can be trivially modified to test limits as well. /* * Copyright (c) 2005, Zachary Amsden (zach@vmware.com) * This is licensed under the GPL. */ #include <stdio.h> #include <signal.h>

Introduce a write acessor for updating the current LDT. This is required for hypervisors like Xen that do not allow LDT pages to be directly written. Testing - here's a fun little LDT test that can be trivially modified to test limits as well. /* * Copyright (c) 2005, Zachary Amsden (zach@vmware.com) * This is licensed under the GPL. */ #include <stdio.h> #include <signal.h>

No need to duplicate the same define everywhere. Since the only user is stop-machine and the only provider is s390, we can use a default implementation of cpu_relax_yield in sched.h. Suggested-by: Russell King <linux at armlinux.org.uk> Signed-off-by: Christian Borntraeger <borntraeger at de.ibm.com> --- arch/alpha/include/asm/processor.h | 1 - arch/arc/include/asm/processor.h

No need to duplicate the same define everywhere. Since the only user is stop-machine and the only provider is s390, we can use a default implementation of cpu_relax_yield in sched.h. Suggested-by: Russell King <linux at armlinux.org.uk> Signed-off-by: Christian Borntraeger <borntraeger at de.ibm.com> --- arch/alpha/include/asm/processor.h | 1 - arch/arc/include/asm/processor.h

This round attempts to conclude all of the LDT related cleanup with some finally nice looking LDT code, fixes for the UML build, a bugfix for really rather nasty kprobes problems, and the basic framework for an LDT test suite. It is really rather unfortunate that this code is so difficult to test, even with DOSemu and Wine, there are still very nasty corner cases here - anyone want an iret to

This round attempts to conclude all of the LDT related cleanup with some finally nice looking LDT code, fixes for the UML build, a bugfix for really rather nasty kprobes problems, and the basic framework for an LDT test suite. It is really rather unfortunate that this code is so difficult to test, even with DOSemu and Wine, there are still very nasty corner cases here - anyone want an iret to

Add Xen accessors for LDT updates. Todo: Bring back return values from write_ldt_entry. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.13/arch/i386/kernel/ldt.c =================================================================== --- linux-2.6.13.orig/arch/i386/kernel/ldt.c 2005-08-08 21:13:56.000000000 -0700 +++ linux-2.6.13/arch/i386/kernel/ldt.c 2005-08-08

Add Xen accessors for LDT updates. Todo: Bring back return values from write_ldt_entry. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.13/arch/i386/kernel/ldt.c =================================================================== --- linux-2.6.13.orig/arch/i386/kernel/ldt.c 2005-08-08 21:13:56.000000000 -0700 +++ linux-2.6.13/arch/i386/kernel/ldt.c 2005-08-08

Chris Wright wrote: >* Zachary Amsden (zach@vmware.com) wrote: > > >>Does Xen assume page aligned descriptor tables? I assume from this >> >> > >Yes. > > > >>patch and snippets I have gathered from others, that is a yes, and other >>things here imply that DT pages are not shadowed. If so, Xen itself >>must have live segments

Chris Wright wrote: >* Zachary Amsden (zach@vmware.com) wrote: > > >>Does Xen assume page aligned descriptor tables? I assume from this >> >> > >Yes. > > > >>patch and snippets I have gathered from others, that is a yes, and other >>things here imply that DT pages are not shadowed. If so, Xen itself >>must have live segments

Hey again, Am 2014-08-19 12:26, schrieb Jonas Meurer: > I encounter kernel crashes on an up-to-date Debian/Wheezy Xen domU with > the > stock kernel. The dom0 runs the same linux kernel and > xen/4.1.4-3+deb7u1. the bug is still reproducible with the latest kernel and Xen packages from Debian Wheezy. Unfortunately it seems like a corner case, somehow related to the hardware

For spinning loops people do often use barrier() or cpu_relax(). For most architectures cpu_relax and barrier are the same, but on some architectures cpu_relax can add some latency. For example on power,sparc64 and arc, cpu_relax can shift the CPU towards other hardware threads in an SMT environment. On s390 cpu_relax does even more, it uses an hypercall to the hypervisor to give up the timeslice.

Xen requires error returns from the hypercall to update LDT entries, and this generates completely equivalent code on native. Patch-base: 2.6.13-rc5-mm1 Patch-keys: i386 desc ldt paravirt xen Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.13/include/asm-i386/mach-default/mach_desc.h =================================================================== ---

Xen requires error returns from the hypercall to update LDT entries, and this generates completely equivalent code on native. Patch-base: 2.6.13-rc5-mm1 Patch-keys: i386 desc ldt paravirt xen Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.13/include/asm-i386/mach-default/mach_desc.h =================================================================== ---

As there are no users left, we can remove cpu_relax_lowlatency. Signed-off-by: Christian Borntraeger <borntraeger at de.ibm.com> --- arch/alpha/include/asm/processor.h | 1 - arch/arc/include/asm/processor.h | 2 -- arch/arm/include/asm/processor.h | 1 - arch/arm64/include/asm/processor.h | 1 - arch/avr32/include/asm/processor.h | 1 -

Hi, Patch below is needed to make my system work stable in PAE mode. Havn''t seen problems without PAE, not sure whenever thats just pure luck or whenever there is a bug in my PAE xenlinux kernel. To me it looks like a generic bug though. I''ve actually trapped into problems with unpin only: A process exits, somewhere in exit_mm() the page tables are unpinned, shortly thereafter