lwn.git/arch/arm64/kvm/hyp/debug-sr.c, branch docs-mw

KVM: arm64: Split hyp/debug-sr.c to VHE/nVHE

2020-07-05T17:38:25+00:00

debug-sr.c contains KVM's code for context-switching debug registers, with some code shared between VHE/nVHE. These common routines are moved to a header file, VHE-specific code is moved to vhe/debug-sr.c and nVHE-specific code to nvhe/debug-sr.c. Functions are slightly refactored to move code hidden behind `has_vhe()` checks to the corresponding .c files. Signed-off-by: David Brazdil Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20200625131420.71444-11-dbrazdil@google.com

KVM: arm64: Remove host_cpu_context member from vcpu structure

2020-06-09T09:59:52+00:00

For very long, we have kept this pointer back to the per-cpu host state, despite having working per-cpu accessors at EL2 for some time now. Recent investigations have shown that this pointer is easy to abuse in preemptible context, which is a sure sign that it would better be gone. Not to mention that a per-cpu pointer is faster to access at all times. Reported-by: Andrew Scull Acked-by: Mark Rutland Signed-off-by: Marc Zyngier

arm64: KVM: hyp: debug-sr: Mark expected switch fall-through

2019-07-29T10:01:37+00:00

When fall-through warnings was enabled by default the following warnings was starting to show up: ../arch/arm64/kvm/hyp/debug-sr.c: In function ‘__debug_save_state’: ../arch/arm64/kvm/hyp/debug-sr.c:20:19: warning: this statement may fall through [-Wimplicit-fallthrough=] case 15: ptr[15] = read_debug(reg, 15); \ ../arch/arm64/kvm/hyp/debug-sr.c:113:2: note: in expansion of macro ‘save_debug’ save_debug(dbg->dbg_bcr, dbgbcr, brps); ^~~~~~~~~~ ../arch/arm64/kvm/hyp/debug-sr.c:21:2: note: here case 14: ptr[14] = read_debug(reg, 14); \ ^~~~ ../arch/arm64/kvm/hyp/debug-sr.c:113:2: note: in expansion of macro ‘save_debug’ save_debug(dbg->dbg_bcr, dbgbcr, brps); ^~~~~~~~~~ ../arch/arm64/kvm/hyp/debug-sr.c:21:19: warning: this statement may fall through [-Wimplicit-fallthrough=] case 14: ptr[14] = read_debug(reg, 14); \ ../arch/arm64/kvm/hyp/debug-sr.c:113:2: note: in expansion of macro ‘save_debug’ save_debug(dbg->dbg_bcr, dbgbcr, brps); ^~~~~~~~~~ ../arch/arm64/kvm/hyp/debug-sr.c:22:2: note: here case 13: ptr[13] = read_debug(reg, 13); \ ^~~~ ../arch/arm64/kvm/hyp/debug-sr.c:113:2: note: in expansion of macro ‘save_debug’ save_debug(dbg->dbg_bcr, dbgbcr, brps); ^~~~~~~~~~ Rework to add a 'Fall through' comment where the compiler warned about fall-through, hence silencing the warning. Fixes: d93512ef0f0e ("Makefile: Globally enable fall-through warning") Signed-off-by: Anders Roxell [maz: fixed commit message] Signed-off-by: Marc Zyngier

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234

2019-06-19T15:09:07+00:00

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 see http www gnu org licenses extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 503 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Alexios Zavras Reviewed-by: Allison Randal Reviewed-by: Enrico Weigelt Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de Signed-off-by: Greg Kroah-Hartman

KVM: arm64: Repurpose vcpu_arch.debug_flags for general-purpose flags

2018-05-25T11:28:13+00:00

In struct vcpu_arch, the debug_flags field is used to store debug-related flags about the vcpu state. Since we are about to add some more flags related to FPSIMD and SVE, it makes sense to add them to the existing flags field rather than adding new fields. Since there is only one debug_flags flag defined so far, there is plenty of free space for expansion. In preparation for adding more flags, this patch renames the debug_flags field to simply "flags", and updates comments appropriately. The flag definitions are also moved to , since their presence in was for purely historical reasons: these definitions are not used from asm any more, and not very likely to be as more Hyp asm is migrated to C. KVM_ARM64_DEBUG_DIRTY_SHIFT has not been used since commit 1ea66d27e7b0 ("arm64: KVM: Move away from the assembly version of the world switch"), so this patch gets rid of that too. No functional change. Signed-off-by: Dave Martin Reviewed-by: Marc Zyngier Reviewed-by: Alex Bennée Acked-by: Christoffer Dall [maz: fixed minor conflict] Signed-off-by: Marc Zyngier

KVM: arm64: Improve debug register save/restore flow

2018-03-19T10:53:12+00:00

Instead of having multiple calls from the world switch path to the debug logic, each figuring out if the dirty bit is set and if we should save/restore the debug registers, let's just provide two hooks to the debug save/restore functionality, one for switching to the guest context, and one for switching to the host context, and we get the benefit of only having to evaluate the dirty flag once on each path, plus we give the compiler some more room to inline some of this functionality. Reviewed-by: Marc Zyngier Reviewed-by: Andrew Jones Signed-off-by: Christoffer Dall Signed-off-by: Marc Zyngier

KVM: arm64: Slightly improve debug save/restore functions

2018-03-19T10:53:12+00:00

The debug save/restore functions can be improved by using the has_vhe() static key instead of the instruction alternative. Using the static key uses the same paradigm as we're going to use elsewhere, it makes the code more readable, and it generates slightly better code (no stack setups and function calls unless necessary). We also use a static key on the restore path, because it will be marginally faster than loading a value from memory. Finally, we don't have to conditionally clear the debug dirty flag if it's set, we can just clear it. Reviewed-by: Marc Zyngier Reviewed-by: Andrew Jones Signed-off-by: Christoffer Dall Signed-off-by: Marc Zyngier

KVM: arm64: Move debug dirty flag calculation out of world switch

2018-03-19T10:53:11+00:00

There is no need to figure out inside the world-switch if we should save/restore the debug registers or not, we might as well do that in the higher level debug setup code, making it easier to optimize down the line. Reviewed-by: Julien Thierry Reviewed-by: Marc Zyngier Reviewed-by: Andrew Jones Signed-off-by: Christoffer Dall Signed-off-by: Marc Zyngier

Merge branch 'x86/hyperv' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2018-02-01T14:04:17+00:00

Topic branch for stable KVM clockource under Hyper-V. Thanks to Christoffer Dall for resolving the ARM conflict.

KVM: arm/arm64: Detangle kvm_mmu.h from kvm_hyp.h

2018-01-08T14:20:43+00:00

kvm_hyp.h has an odd dependency on kvm_mmu.h, which makes the opposite inclusion impossible. Let's start with breaking that useless dependency. Acked-by: Christoffer Dall Signed-off-by: Marc Zyngier Signed-off-by: Christoffer Dall