similar to: [PATCH 3/3] Gdt page isolation

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:

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. 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 +++

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

As suggested by Andi Kleen, don't allocate a GDT page if there is already one present. Needed for CPU hotplug. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.14-rc1/arch/i386/kernel/smpboot.c =================================================================== --- linux-2.6.14-rc1.orig/arch/i386/kernel/smpboot.c 2005-09-20 20:38:22.000000000 -0700 +++

As suggested by Andi Kleen, don't allocate a GDT page if there is already one present. Needed for CPU hotplug. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.14-rc1/arch/i386/kernel/smpboot.c =================================================================== --- linux-2.6.14-rc1.orig/arch/i386/kernel/smpboot.c 2005-09-20 20:38:22.000000000 -0700 +++

The per-CPU initialization code is copying in bogus data into thread->tls_array. Note that it copies &per_cpu(cpu_gdt_table, cpu), not &per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_TLS_MIN). That is totally broken and unnecessary. Make the initialization explicitly NULL. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.14-rc1/arch/i386/kernel/cpu/common.c

The per-CPU initialization code is copying in bogus data into thread->tls_array. Note that it copies &per_cpu(cpu_gdt_table, cpu), not &per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_TLS_MIN). That is totally broken and unnecessary. Make the initialization explicitly NULL. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.14-rc1/arch/i386/kernel/cpu/common.c

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

Andrew Morton's fix for PnP BIOS. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.14-rc1/drivers/pnp/pnpbios/bioscalls.c =================================================================== --- linux-2.6.14-rc1.orig/drivers/pnp/pnpbios/bioscalls.c 2005-08-28 16:41:01.000000000 -0700 +++ linux-2.6.14-rc1/drivers/pnp/pnpbios/bioscalls.c 2005-09-28 13:13:42.000000000 -0700

Andrew Morton's fix for PnP BIOS. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.14-rc1/drivers/pnp/pnpbios/bioscalls.c =================================================================== --- linux-2.6.14-rc1.orig/drivers/pnp/pnpbios/bioscalls.c 2005-08-28 16:41:01.000000000 -0700 +++ linux-2.6.14-rc1/drivers/pnp/pnpbios/bioscalls.c 2005-09-28 13:13:42.000000000 -0700

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 =================================================================== ---

The per-CPU initialization code is copying in bogus data into thread->tls_array. Note that it copies &per_cpu(cpu_gdt_table, cpu), not &per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_TLS_MIN). That is totally broken and unnecessary. Make the initialization explicitly NULL. Signed-off-by: Zachary Amsden <zach@vmware.com Index: linux-2.6.13/include/asm-i386/processor.h

The per-CPU initialization code is copying in bogus data into thread->tls_array. Note that it copies &per_cpu(cpu_gdt_table, cpu), not &per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_TLS_MIN). That is totally broken and unnecessary. Make the initialization explicitly NULL. Signed-off-by: Zachary Amsden <zach@vmware.com Index: linux-2.6.13/include/asm-i386/processor.h

PnP BIOS for x86 is part of drivers, so I missed it in the initial GDT page alignment patch. Kudos to Andrew for fixing that. Unfortunately, fixing the build introduced a kernel panic when trying to setup the as of yet unallocated GDTs for the APs. This fixes the problem by setting only the BSP's GDT, then copying the PnP segments back to the cpu_gdt_table template. Signed-off-by: Zachary