similar to: [PATCH 10/21] i386 Use protected segment for 16bit stack

Index: linux-2.6.13/include/asm-i386/desc.h =================================================================== --- linux-2.6.13.orig/include/asm-i386/desc.h 2005-08-08 17:15:56.000000000 -0700 +++ linux-2.6.13/include/asm-i386/desc.h 2005-08-08 17:16:07.000000000 -0700 @@ -21,6 +21,8 @@ extern struct desc_struct cpu_gdt_table[GDT_ENTRIES]; DECLARE_PER_CPU(struct desc_struct,

Index: linux-2.6.13/include/asm-i386/desc.h =================================================================== --- linux-2.6.13.orig/include/asm-i386/desc.h 2005-08-08 17:15:56.000000000 -0700 +++ linux-2.6.13/include/asm-i386/desc.h 2005-08-08 17:16:07.000000000 -0700 @@ -21,6 +21,8 @@ extern struct desc_struct cpu_gdt_table[GDT_ENTRIES]; DECLARE_PER_CPU(struct desc_struct,

Add an accessor function for getting the per-CPU gdt. Callee must already have the CPU. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.14-rc1/include/asm-i386/desc.h =================================================================== --- linux-2.6.14-rc1.orig/include/asm-i386/desc.h 2005-09-20 14:49:10.000000000 -0700 +++ linux-2.6.14-rc1/include/asm-i386/desc.h

Add an accessor function for getting the per-CPU gdt. Callee must already have the CPU. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.14-rc1/include/asm-i386/desc.h =================================================================== --- linux-2.6.14-rc1.orig/include/asm-i386/desc.h 2005-09-20 14:49:10.000000000 -0700 +++ linux-2.6.14-rc1/include/asm-i386/desc.h

Add an accessor function for getting the per-CPU gdt. Callee must already have the CPU. Patch-base: 2.6.13-rc5-mm1 Patch-keys: i386 desc xen Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.13/include/asm-i386/desc.h =================================================================== --- linux-2.6.13.orig/include/asm-i386/desc.h 2005-08-09 20:17:21.000000000 -0700 +++

Add an accessor function for getting the per-CPU gdt. Callee must already have the CPU. Patch-base: 2.6.13-rc5-mm1 Patch-keys: i386 desc xen Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.13/include/asm-i386/desc.h =================================================================== --- linux-2.6.13.orig/include/asm-i386/desc.h 2005-08-09 20:17:21.000000000 -0700 +++

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

Both the APM BIOS and PnP BIOS code use a segment hack to simulate real mode selector 0x40 (which points to the BIOS data area at 0x00400 in real mode). Several broken BIOSen use selector 0x40 as if they were running in real mode, which we make work by faking up selector 0x40 in the GDT to point to physical memory starting at 0x400. We limit the access to the remainder of this physical page

Both the APM BIOS and PnP BIOS code use a segment hack to simulate real mode selector 0x40 (which points to the BIOS data area at 0x00400 in real mode). Several broken BIOSen use selector 0x40 as if they were running in real mode, which we make work by faking up selector 0x40 in the GDT to point to physical memory starting at 0x400. We limit the access to the remainder of this physical page

OK, here it is. Benchmarks still coming. This is against Andi's 2.6.18-rc7-git3 tree, and replaces the patches between (and not including) i386-pda-asm-offsets and i386-early-fault. One patch is identical, one is mildly modified, the rest are re-implemented but inspired by Jeremy's PDA work. Thanks, Rusty. -- Help! Save Australia from the worst of the DMCA: http://linux.org.au/law

OK, here it is. Benchmarks still coming. This is against Andi's 2.6.18-rc7-git3 tree, and replaces the patches between (and not including) i386-pda-asm-offsets and i386-early-fault. One patch is identical, one is mildly modified, the rest are re-implemented but inspired by Jeremy's PDA work. Thanks, Rusty. -- Help! Save Australia from the worst of the DMCA: http://linux.org.au/law

Hi Jeremy, all, Sorry this took so long, spent last week in Japan at OSDL conf then netconf. After several false starts, I ended up with a very simple implementation, which clashes significantly with your work since then 8(. I've pushed the patches anyway, but it's going to be significant work for me to re-merge them, so I wanted your feedback first. The first patch simply changes

Hi Jeremy, all, Sorry this took so long, spent last week in Japan at OSDL conf then netconf. After several false starts, I ended up with a very simple implementation, which clashes significantly with your work since then 8(. I've pushed the patches anyway, but it's going to be significant work for me to re-merge them, so I wanted your feedback first. The first patch simply changes

Make GDT page aligned and page padded to support running inside of a hypervisor. This prevents false sharing of the GDT page with other hot data, which is not allowed in Xen, and causes performance problems in VMware. Rather than go back to the old method of statically allocating the GDT (which wastes unneded space for non-present CPUs), the GDT for APs is allocated dynamically. Signed-off-by:

Make GDT page aligned and page padded to support running inside of a hypervisor. This prevents false sharing of the GDT page with other hot data, which is not allowed in Xen, and causes performance problems in VMware. Rather than go back to the old method of statically allocating the GDT (which wastes unneded space for non-present CPUs), the GDT for APs is allocated dynamically. Signed-off-by:

Make GDT page aligned and page padded to support running inside of a hypervisor. This prevents false sharing of the GDT page with other hot data, which is not allowed in Xen, and causes performance problems in VMware. Rather than go back to the old method of statically allocating the GDT (which wastes unneded space for non-present CPUs), the GDT for APs is allocated dynamically. Signed-off-by:

Make GDT page aligned and page padded to support running inside of a hypervisor. This prevents false sharing of the GDT page with other hot data, which is not allowed in Xen, and causes performance problems in VMware. Rather than go back to the old method of statically allocating the GDT (which wastes unneded space for non-present CPUs), the GDT for APs is allocated dynamically. Signed-off-by:

With the only bit in CR0 permitted to be changed by PV guests being TS, optimize the handling towards that: Keep a cached value in a per-CPU variable, and issue HYPERVISOR_fpu_taskswitch hypercalls for updates in all but the unusual case should something in the system still try to modify another bit (the attempt of which would then be logged by the hypervisor). This removes the need to have the

It is impossible to have a zero length segment in descriptor tables using "normal" segments. One of many ways to properly protect segments to zero length is to map the base to an umapped page. Create a nicer way to do this, and stop subtracting 1 from the length passed to set_limit (note calling set limit with a zero limit does something very bad! - not anymore). Signed-off-by: