linux-dev/arch/powerpc/kernel/kvm.c, branch linus/master

gup: Turn fault_in_pages_{readable,writeable} into fault_in_{readable,writeable}

2021-10-18T14:33:03Z

Turn fault_in_pages_{readable,writeable} into versions that return the number of bytes not faulted in, similar to copy_to_user, instead of returning a non-zero value when any of the requested pages couldn't be faulted in. This supports the existing users that require all pages to be faulted in as well as new users that are happy if any pages can be faulted in. Rename the functions to fault_in_{readable,writeable} to make sure this change doesn't silently break things. Neither of these functions is entirely trivial and it doesn't seem useful to inline them, so move them to mm/gup.c. Signed-off-by: Andreas Gruenbacher

powerpc/kvm: Fix kvm_use_magic_page

2021-10-18T14:31:45Z

When switching from __get_user to fault_in_pages_readable, commit 9f9eae5ce717 broke kvm_use_magic_page: like __get_user, fault_in_pages_readable returns 0 on success. Fixes: 9f9eae5ce717 ("powerpc/kvm: Prefer fault_in_pages_readable function") Cc: stable@vger.kernel.org # v4.18+ Signed-off-by: Andreas Gruenbacher

powerpc/kvm: Explicitly mark kvm guest code as __init

2019-09-13T14:04:40Z

All the code in kvm.c can be marked __init. Most of it is already inlined into the initcall, but not all. So instead of relying on the inlining, mark it all as __init. This saves ~280 bytes of text for my configuration. Signed-off-by: Michael Ellerman Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190911115746.12433-3-mpe@ellerman.id.au

powerpc/kvm: Move kvm_tmp into .text, shrink to 64K

2019-09-13T14:04:40Z

In some configurations of KVM, guests binary patch themselves to avoid/reduce trapping into the hypervisor. For some instructions this requires replacing one instruction with a sequence of instructions. For those cases we need to write the sequence of instructions somewhere and then patch the location of the original instruction to branch to the sequence. That requires that the location of the sequence be within 32MB of the original instruction. The current solution for this is that we create a 1MB array in BSS, write sequences into there, and then free the remainder of the array. This has a few problems: - it confuses kmemleak. - it confuses lockdep. - it requires mapping kvm_tmp executable, which can cause adjacent areas to also be mapped executable if we're using 16M pages for the linear mapping. - the 32MB limit can be exceeded if the kernel is big enough, especially with STRICT_KERNEL_RWX enabled, which then prevents the patching from working at all. We can fix all those problems by making kvm_tmp just a region of regular .text. However currently it's 1MB in size, and we don't want to waste 1MB of text. In practice however I only see ~30KB of kvm_tmp being used even for an allyes_config. So shrink kvm_tmp to 64K, which ought to be enough for everyone, and move it into .text. Signed-off-by: Michael Ellerman Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190911115746.12433-1-mpe@ellerman.id.au

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 266

2019-06-05T15:30:28Z

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation 51 franklin street fifth floor boston ma 02110 1301 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 67 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Richard Fontana Reviewed-by: Alexios Zavras Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190529141333.953658117@linutronix.de Signed-off-by: Greg Kroah-Hartman

kmemleak: powerpc: skip scanning holes in the .bss section

2019-04-06T02:02:30Z

Commit 2d4f567103ff ("KVM: PPC: Introduce kvm_tmp framework") adds kvm_tmp[] into the .bss section and then free the rest of unused spaces back to the page allocator. kernel_init kvm_guest_init kvm_free_tmp free_reserved_area free_unref_page free_unref_page_prepare With DEBUG_PAGEALLOC=y, it will unmap those pages from kernel. As the result, kmemleak scan will trigger a panic when it scans the .bss section with unmapped pages. This patch creates dedicated kmemleak objects for the .data, .bss and potentially .data..ro_after_init sections to allow partial freeing via the kmemleak_free_part() in the powerpc kvm_free_tmp() function. Link: http://lkml.kernel.org/r/20190321171917.62049-1-catalin.marinas@arm.com Signed-off-by: Catalin Marinas Reported-by: Qian Cai Acked-by: Michael Ellerman (powerpc) Tested-by: Qian Cai Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Avi Kivity Cc: Paolo Bonzini Cc: Radim Krcmar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

powerpc/kvm: Prefer fault_in_pages_readable function

2018-05-17T04:12:40Z

Directly use fault_in_pages_readable instead of manual __get_user code. Fix warning treated as error with W=1: arch/powerpc/kernel/kvm.c:675:6: error: variable ‘tmp’ set but not used [-Werror=unused-but-set-variable] Suggested-by: Christophe Leroy Signed-off-by: Mathieu Malaterre Reviewed-by: Christophe Leroy Signed-off-by: Michael Ellerman

powerpc/64: Fix watchdog configuration regressions

2017-08-31T04:26:00Z

This fixes a couple more bits of fallout from the new hard lockup watchdog patch. It restores the required hw_nmi_get_sample_period() function for the perf watchdog, and removes some function declarations on 64e that are only defined for 64s. This fixes the 64e build when the hardlockup detector is enabled. It restores the default behaviour of disabling the perf watchdog, and also fixes disabling the 64s watchdog when running as a guest. Fixes: 2104180a53 ("powerpc/64s: implement arch-specific hardlockup watchdog") Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman

powerpc/64s: implement arch-specific hardlockup watchdog

2017-07-12T23:26:02Z

Implement an arch-speicfic watchdog rather than use the perf-based hardlockup detector. The new watchdog takes the soft-NMI directly, rather than going through perf. Perf interrupts are to be made maskable in future, so that would prevent the perf detector from working in those regions. Additionally, implement a SMP based detector where all CPUs watch one another by pinging a shared cpumask. This is because powerpc Book3S does not have a true periodic local NMI, but some platforms do implement a true NMI IPI. If a CPU is stuck with interrupts hard disabled, the soft-NMI watchdog does not work, but the SMP watchdog will. Even on platforms without a true NMI IPI to get a good trace from the stuck CPU, other CPUs will notice the lockup sufficiently to report it and panic. [npiggin@gmail.com: honor watchdog disable at boot/hotplug] Link: http://lkml.kernel.org/r/20170621001346.5bb337c9@roar.ozlabs.ibm.com [npiggin@gmail.com: fix false positive warning at CPU unplug] Link: http://lkml.kernel.org/r/20170630080740.20766-1-npiggin@gmail.com [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20170616065715.18390-6-npiggin@gmail.com Signed-off-by: Nicholas Piggin Reviewed-by: Don Zickus Tested-by: Babu Moger [sparc] Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

powerpc: Remove redundant breaks

2015-08-06T05:10:20Z

break; break; isn't useful. Remove one. Signed-off-by: Joe Perches Signed-off-by: Michael Ellerman