kernel/linux.git/arch/arm64/kvm/debug.c, branch linux-5.9.y

KVM: arm64: Write arch.mdcr_el2 changes since last vcpu_load on VHE

2020-01-22T18:38:04+00:00

On VHE systems arch.mdcr_el2 is written to mdcr_el2 at vcpu_load time to set options for self-hosted debug and the performance monitors extension. Unfortunately the value of arch.mdcr_el2 is not calculated until kvm_arm_setup_debug() in the run loop after the vcpu has been loaded. This means that the initial brief iterations of the run loop use a zero value of mdcr_el2 - until the vcpu is preempted. This also results in a delay between changes to vcpu->guest_debug taking effect. Fix this by writing to mdcr_el2 in kvm_arm_setup_debug() on VHE systems when a change to arch.mdcr_el2 has been detected. Fixes: d5a21bcc2995 ("KVM: arm64: Move common VHE/non-VHE trap config in separate functions") Cc: # 4.17.x- Suggested-by: James Morse Acked-by: Will Deacon Reviewed-by: Marc Zyngier Signed-off-by: Andrew Murray Signed-off-by: Catalin Marinas

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

arm/arm64: KVM: Introduce kvm_call_hyp_ret()

2019-02-19T21:05:24+00:00

Until now, we haven't differentiated between HYP calls that have a return value and those who don't. As we're about to change this, introduce kvm_call_hyp_ret(), and change all call sites that actually make use of a return value. Signed-off-by: Marc Zyngier Acked-by: Christoffer Dall Signed-off-by: Christoffer Dall

arm64: KVM: Consistently advance singlestep when emulating instructions

2018-12-18T14:11:37+00:00

When we emulate a guest instruction, we don't advance the hardware singlestep state machine, and thus the guest will receive a software step exception after a next instruction which is not emulated by the host. We bodge around this in an ad-hoc fashion. Sometimes we explicitly check whether userspace requested a single step, and fake a debug exception from within the kernel. Other times, we advance the HW singlestep state rely on the HW to generate the exception for us. Thus, the observed step behaviour differs for host and guest. Let's make this simpler and consistent by always advancing the HW singlestep state machine when we skip an instruction. Thus we can rely on the hardware to generate the singlestep exception for us, and never need to explicitly check for an active-pending step, nor do we need to fake a debug exception from the guest. Cc: Peter Maydell Reviewed-by: Alex Bennée Reviewed-by: Christoffer Dall Signed-off-by: Mark Rutland Signed-off-by: Marc Zyngier

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: Rewrite system register accessors to read/write functions

2018-03-19T10:53:16+00:00

Currently we access the system registers array via the vcpu_sys_reg() macro. However, we are about to change the behavior to some times modify the register file directly, so let's change this to two primitives: * Accessor macros vcpu_write_sys_reg() and vcpu_read_sys_reg() * Direct array access macro __vcpu_sys_reg() The accessor macros should be used in places where the code needs to access the currently loaded VCPU's state as observed by the guest. For example, when trapping on cache related registers, a write to a system register should go directly to the VCPU version of the register. The direct array access macro can be used in places where the VCPU is known to never be running (for example userspace access) or for registers which are never context switched (for example all the PMU system registers). This rewrites all users of vcpu_sys_regs to one of the macros described above. No functional change. Acked-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

KVM: arm/arm64: debug: Introduce helper for single-step

2017-11-29T15:46:19+00:00

After emulating instructions we may want return to user-space to handle single-step debugging. Introduce a helper function, which, if single-step is enabled, sets the run structure for return and returns true. Signed-off-by: Alex Bennée Reviewed-by: Julien Thierry Signed-off-by: Christoffer Dall

arm64: KVM: Save/restore the host SPE state when entering/leaving a VM

2017-02-02T18:33:01+00:00

The SPE buffer is virtually addressed, using the page tables of the CPU MMU. Unusually, this means that the EL0/1 page table may be live whilst we're executing at EL2 on non-VHE configurations. When VHE is in use, we can use the same property to profile the guest behind its back. This patch adds the relevant disabling and flushing code to KVM so that the host can make use of SPE without corrupting guest memory, and any attempts by a guest to use SPE will result in a trap. Acked-by: Marc Zyngier Cc: Alex Bennée Cc: Christoffer Dall Signed-off-by: Will Deacon

KVM: arm64: add trace points for guest_debug debug

2015-07-21T11:50:43+00:00

This includes trace points for: kvm_arch_setup_guest_debug kvm_arch_clear_guest_debug I've also added some generic register setting trace events and also a trace point to dump the array of hardware registers. Acked-by: Christoffer Dall Signed-off-by: Alex Bennée Signed-off-by: Marc Zyngier