similar to: [PATCH 20/21] i386 Ldt cleanups 3

* 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

By moving init_new_context and destroy_context inline into mmu_context.h, we can avoid extra functions calls, which are only needed for the unlikely case that the process context has an LDT to deal with. Now the code in ldt.c is called only when actually dealing with LDT creation or destruction. Careful analysis of alloc_ldt function showed that by using two const parameters, huge amounts of

By moving init_new_context and destroy_context inline into mmu_context.h, we can avoid extra functions calls, which are only needed for the unlikely case that the process context has an LDT to deal with. Now the code in ldt.c is called only when actually dealing with LDT creation or destruction. Careful analysis of alloc_ldt function showed that by using two const parameters, huge amounts of

Index: linux-2.6.13/arch/i386/kernel/ldt.c =================================================================== --- linux-2.6.13.orig/arch/i386/kernel/ldt.c 2005-08-08 15:27:26.000000000 -0700 +++ linux-2.6.13/arch/i386/kernel/ldt.c 2005-08-08 21:13:19.000000000 -0700 @@ -18,6 +18,7 @@ #include <asm/system.h> #include <asm/ldt.h> #include <asm/desc.h> +#include

Index: linux-2.6.13/arch/i386/kernel/ldt.c =================================================================== --- linux-2.6.13.orig/arch/i386/kernel/ldt.c 2005-08-08 15:27:26.000000000 -0700 +++ linux-2.6.13/arch/i386/kernel/ldt.c 2005-08-08 21:13:19.000000000 -0700 @@ -18,6 +18,7 @@ #include <asm/system.h> #include <asm/ldt.h> #include <asm/desc.h> +#include

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

Add hooks that the hypervisor can use to establish writable and non-writable pages for LDT pages. I made these parallel the page flags as defined in include/linux/page-flags.h, since the flag mechanism is very similar to the hypercall page flagging, and extended easily later to include PT, PD, PDP, GDT, etc. Patch-against: 2.6.13-rc5-mm1 Patch-keys: i386 ldt paravirt xen Signed-off-by: Zachary

Add hooks that the hypervisor can use to establish writable and non-writable pages for LDT pages. I made these parallel the page flags as defined in include/linux/page-flags.h, since the flag mechanism is very similar to the hypercall page flagging, and extended easily later to include PT, PD, PDP, GDT, etc. Patch-against: 2.6.13-rc5-mm1 Patch-keys: i386 ldt paravirt xen Signed-off-by: Zachary

I was also able to get the LDT switching functionality out of the critical path in switch_mm, which reduces the number of function calls, potential TLB misses and code size. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.14-zach-work/include/asm-i386/desc.h =================================================================== ---

I was also able to get the LDT switching functionality out of the critical path in switch_mm, which reduces the number of function calls, potential TLB misses and code size. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.14-zach-work/include/asm-i386/desc.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>

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>

Xen uses lazy pinning of MM structures including the page table root and LDT, which requires hooks at context creation and destruction time to maintain the lazy list. Patch-against: 2.6.13-rc5-mm1 Patch-keys: i386 mmu paravirt xen Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.13/include/asm-i386/mmu_context.h

Xen uses lazy pinning of MM structures including the page table root and LDT, which requires hooks at context creation and destruction time to maintain the lazy list. Patch-against: 2.6.13-rc5-mm1 Patch-keys: i386 mmu paravirt xen Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.13/include/asm-i386/mmu_context.h

On Fri, 23 Jun 2023 23:14:39 +0200, Julia Lawall <Julia.Lawall at inria.fr> wrote: > Use array_size to protect against multiplication overflows. > > The changes were done using the following Coccinelle semantic patch: > > // <smpl> > @@ > expression E1, E2; > constant C1, C2; > identifier alloc = {vmalloc,vzalloc}; > @@ > > ( >

plain text document attachment (xx-paravirt-desc-header.patch) Update the descriptors for an interface with paravirt ops Signed-off-by: Steven Rostedt srostedt@redhat.com Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com> Index: clean-start/include/asm-x86_64/desc.h =================================================================== ---

plain text document attachment (xx-paravirt-desc-header.patch) Update the descriptors for an interface with paravirt ops Signed-off-by: Steven Rostedt srostedt@redhat.com Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com> Index: clean-start/include/asm-x86_64/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 =================================================================== ---