similar to: [PATCH, experimental] i386 Allow the fixmap to be relocated at boot time

Paravirt-ops guests which move the fixmap also end up moving the syscall = VDSO. This fails if it is prelinked at a fixed address, which is why = COMPAT_VDSO is broken under CONFIG_VMI (and also under CONFIG_XEN). = Several options are available to try to address this. Jan had cooked up = a patch for Xen that used build magic to find the parts of the VDSO that = need relocation. I

Paravirt-ops guests which move the fixmap also end up moving the syscall = VDSO. This fails if it is prelinked at a fixed address, which is why = COMPAT_VDSO is broken under CONFIG_VMI (and also under CONFIG_XEN). = Several options are available to try to address this. Jan had cooked up = a patch for Xen that used build magic to find the parts of the VDSO that = need relocation. I

So, is everyone happy with this smerge of Ingo and Gerd's work? Reposted below. Thanks, Rusty. -------- Forwarded Message -------- From: Linus Torvalds <torvalds@osdl.org> To: Rusty Russell <rusty@rustcorp.com.au> Cc: Andrew Morton <akpm@osdl.org> Subject: Re: [Fwd: [Fwd: FW: argh]] Date: Wed, 17 May 2006 21:35:51 -0700 (PDT) On Thu, 18 May 2006, Rusty Russell wrote: >

So, is everyone happy with this smerge of Ingo and Gerd's work? Reposted below. Thanks, Rusty. -------- Forwarded Message -------- From: Linus Torvalds <torvalds@osdl.org> To: Rusty Russell <rusty@rustcorp.com.au> Cc: Andrew Morton <akpm@osdl.org> Subject: Re: [Fwd: [Fwd: FW: argh]] Date: Wed, 17 May 2006 21:35:51 -0700 (PDT) On Thu, 18 May 2006, Rusty Russell wrote: >

AFAICT we'll pay one extra TLB entry for this patch. Zach had a patch which left the vsyscall page at the top of memory (minus hole for hypervisor) and patched the ELF header at boot. Thoughts welcome, Rusty. Name: Move vsyscall page out of fixmap, above stack Author: Gerd Hoffmann <kraxel@suse.de> Hypervisors want to use memory at the top of the address space (eg. 64MB for Xen, or

AFAICT we'll pay one extra TLB entry for this patch. Zach had a patch which left the vsyscall page at the top of memory (minus hole for hypervisor) and patched the ELF header at boot. Thoughts welcome, Rusty. Name: Move vsyscall page out of fixmap, above stack Author: Gerd Hoffmann <kraxel@suse.de> Hypervisors want to use memory at the top of the address space (eg. 64MB for Xen, or

Adapt module loading to support PIE relocations. Generate dynamic GOT if a symbol requires it but no entry exist in the kernel GOT. Position Independent Executable (PIE) support will allow to extended the KASLR randomization range below the -2G memory limit. Signed-off-by: Thomas Garnier <thgarnie at google.com> --- arch/x86/Makefile | 4 + arch/x86/include/asm/module.h

With CONFIG_PARAVIRT, the kernel .text is littered with a bunch of calls to pv_irq_ops function pointers, like: callq *0xffffffff81e3a400 (pv_irq_ops.save_fl) In non-Xen paravirt environments -- including native, KVM, Hyper-V, and VMware -- the above code gets patched by native_patch() to look like this instead: pushfq pop %rax nopl 0x0(%rax,%rax,1) So in most scenarios,

Allow compile time creation of a hole at the high end of linear address space. This makes accomodating a hypervisor a much more tractable problem by giving it ample playground to live in. Currently, the hole size is fixed at config time; I have experimented with dynamically sized holes, and have a later patch that developes this potential, but it becomes much more useful once the exact

Allow compile time creation of a hole at the high end of linear address space. This makes accomodating a hypervisor a much more tractable problem by giving it ample playground to live in. Currently, the hole size is fixed at config time; I have experimented with dynamically sized holes, and have a later patch that developes this potential, but it becomes much more useful once the exact

Hi all, Sorry for the delay. This implements binary patching of call sites for interrupt-related paravirt ops, since no-doubt Andi wasn't the only one to believe this approach is slow. The benchmarks were done on a UP 3GHz Pentium 4 with 512MB of RAM. 2.6.17-rc4 vs 2.6.17-rc4 with CONFIG_PARAVIRT=y vs 2.6.17-rc4 CONFIG_PARAVIRT=y with patch. Summary: with binary patching, the difference

Hi all, Sorry for the delay. This implements binary patching of call sites for interrupt-related paravirt ops, since no-doubt Andi wasn't the only one to believe this approach is slow. The benchmarks were done on a UP 3GHz Pentium 4 with 512MB of RAM. 2.6.17-rc4 vs 2.6.17-rc4 with CONFIG_PARAVIRT=y vs 2.6.17-rc4 CONFIG_PARAVIRT=y with patch. Summary: with binary patching, the difference

On Thu, Jun 08 2023 at 17:33, Hou Wenlong wrote: > On Wed, Jun 07, 2023 at 08:49:15PM +0800, Dave Hansen wrote: >> What problems does this patch set solve? How might that solution be >> visible to end users? Why is this problem important to you? > > We want to build the kernel as PIE and allow the kernel image area, > including the fixmap area, to be placed at any virtual

From: Stefano Stabellini <stefano.stabellini@eu.citrix.com> When NR_CPUS increases the fixmap might need more than the page allocated by head_32.S. This patch introduces the logic to calculate the additional memory that is going to be required by early_ioremap_page_table_range_init: - enough memory to allocate the pte pages needed to cover the fixmap virtual memory range, minus the single

Create a configurable hole in the linear address space at the top of memory. A more advanced interface is needed to negotiate how much space the hypervisor is allowed to steal, but in the end, it seems most likely that a fixed constant size will be chosen for the compiled kernel, potentially propagated to an information page used by paravirtual initialization to determine interface compatibility.

Create a configurable hole in the linear address space at the top of memory. A more advanced interface is needed to negotiate how much space the hypervisor is allowed to steal, but in the end, it seems most likely that a fixed constant size will be chosen for the compiled kernel, potentially propagated to an information page used by paravirtual initialization to determine interface compatibility.

On Mon, 2007-03-05 at 13:06 +0100, Ingo Molnar wrote: > Subject: [patch] paravirt: VDSO page is essential > From: Ingo Molnar <mingo@elte.hu> > > commit 3bbf54725467d604698721384d858b5983b87e8f disables the VDSO for > CONFIG_PARAVIRT kernels. This #ifdeffery was a bad change: the VDSO is > an essential component of Linux, and this change forces all of them to > use

On Mon, 2007-03-05 at 13:06 +0100, Ingo Molnar wrote: > Subject: [patch] paravirt: VDSO page is essential > From: Ingo Molnar <mingo@elte.hu> > > commit 3bbf54725467d604698721384d858b5983b87e8f disables the VDSO for > CONFIG_PARAVIRT kernels. This #ifdeffery was a bad change: the VDSO is > an essential component of Linux, and this change forces all of them to > use

Hi, I want to run a i386 domU on my AMD64. I created a LVM partition with Debian Sarge i386 on it, and set everything up. Now for the compilation of the kernel for i386. In "linux-2.6.12-xenU/" , make ARCH=xen menuconfig, i did: Processor Type (X86) (which was selected, and compiled with X86_64 before) Processor family (Opteron/Athlon64/Hammer/K8) [*] Generic x86 support if

Hi, I want to run a i386 domU on my AMD64. I created a LVM partition with Debian Sarge i386 on it, and set everything up. Now for the compilation of the kernel for i386. In "linux-2.6.12-xenU/" , make ARCH=xen menuconfig, i did: Processor Type (X86) (which was selected, and compiled with X86_64 before) Processor family (Opteron/Athlon64/Hammer/K8) [*] Generic x86 support if