Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity
kernel-fxtec-pro1x/arch/arm64/kvm/debug.c

224 lines
6.7 KiB
C
Raw Normal View History

KVM: arm: introduce kvm_arm_init/setup/clear_debug This is a precursor for later patches which will need to do more to setup debug state before entering the hyp.S switch code. The existing functionality for setting mdcr_el2 has been moved out of hyp.S and now uses the value kept in vcpu->arch.mdcr_el2. As the assembler used to previously mask and preserve MDCR_EL2.HPMN I've had to add a mechanism to save the value of mdcr_el2 as a per-cpu variable during the initialisation code. The kernel never sets this number so we are assuming the bootcode has set up the correct value here. This also moves the conditional setting of the TDA bit from the hyp code into the C code which is currently used for the lazy debug register context switch code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:56 -06:00
/*
* Debug and Guest Debug support
*
* Copyright (C) 2015 - Linaro Ltd
* Author: Alex Bennée <alex.bennee@linaro.org>
*
* 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/>.
*/
#include <linux/kvm_host.h>
KVM: arm64: add trace points for guest_debug debug 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 <christoffer.dall@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:03 -06:00
#include <linux/hw_breakpoint.h>
KVM: arm: introduce kvm_arm_init/setup/clear_debug This is a precursor for later patches which will need to do more to setup debug state before entering the hyp.S switch code. The existing functionality for setting mdcr_el2 has been moved out of hyp.S and now uses the value kept in vcpu->arch.mdcr_el2. As the assembler used to previously mask and preserve MDCR_EL2.HPMN I've had to add a mechanism to save the value of mdcr_el2 as a per-cpu variable during the initialisation code. The kernel never sets this number so we are assuming the bootcode has set up the correct value here. This also moves the conditional setting of the TDA bit from the hyp code into the C code which is currently used for the lazy debug register context switch code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:56 -06:00
KVM: arm64: guest debug, add support for single-step This adds support for single-stepping the guest. To do this we need to manipulate the guests PSTATE.SS and MDSCR_EL1.SS bits to trigger stepping. We take care to preserve MDSCR_EL1 and trap access to it to ensure we don't affect the apparent state of the guest. As we have to enable trapping of all software debug exceptions we suppress the ability of the guest to single-step itself. If we didn't we would have to deal with the exception arriving while the guest was in kernelspace when the guest is expecting to single-step userspace. This is something we don't want to unwind in the kernel. Once the host is no longer debugging the guest its ability to single-step userspace is restored. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:58 -06:00
#include <asm/debug-monitors.h>
#include <asm/kvm_asm.h>
KVM: arm: introduce kvm_arm_init/setup/clear_debug This is a precursor for later patches which will need to do more to setup debug state before entering the hyp.S switch code. The existing functionality for setting mdcr_el2 has been moved out of hyp.S and now uses the value kept in vcpu->arch.mdcr_el2. As the assembler used to previously mask and preserve MDCR_EL2.HPMN I've had to add a mechanism to save the value of mdcr_el2 as a per-cpu variable during the initialisation code. The kernel never sets this number so we are assuming the bootcode has set up the correct value here. This also moves the conditional setting of the TDA bit from the hyp code into the C code which is currently used for the lazy debug register context switch code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:56 -06:00
#include <asm/kvm_arm.h>
KVM: arm64: guest debug, add support for single-step This adds support for single-stepping the guest. To do this we need to manipulate the guests PSTATE.SS and MDSCR_EL1.SS bits to trigger stepping. We take care to preserve MDSCR_EL1 and trap access to it to ensure we don't affect the apparent state of the guest. As we have to enable trapping of all software debug exceptions we suppress the ability of the guest to single-step itself. If we didn't we would have to deal with the exception arriving while the guest was in kernelspace when the guest is expecting to single-step userspace. This is something we don't want to unwind in the kernel. Once the host is no longer debugging the guest its ability to single-step userspace is restored. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:58 -06:00
#include <asm/kvm_emulate.h>
KVM: arm64: add trace points for guest_debug debug 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 <christoffer.dall@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:03 -06:00
#include "trace.h"
KVM: arm64: guest debug, add support for single-step This adds support for single-stepping the guest. To do this we need to manipulate the guests PSTATE.SS and MDSCR_EL1.SS bits to trigger stepping. We take care to preserve MDSCR_EL1 and trap access to it to ensure we don't affect the apparent state of the guest. As we have to enable trapping of all software debug exceptions we suppress the ability of the guest to single-step itself. If we didn't we would have to deal with the exception arriving while the guest was in kernelspace when the guest is expecting to single-step userspace. This is something we don't want to unwind in the kernel. Once the host is no longer debugging the guest its ability to single-step userspace is restored. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:58 -06:00
/* These are the bits of MDSCR_EL1 we may manipulate */
#define MDSCR_EL1_DEBUG_MASK (DBG_MDSCR_SS | \
DBG_MDSCR_KDE | \
DBG_MDSCR_MDE)
KVM: arm: introduce kvm_arm_init/setup/clear_debug This is a precursor for later patches which will need to do more to setup debug state before entering the hyp.S switch code. The existing functionality for setting mdcr_el2 has been moved out of hyp.S and now uses the value kept in vcpu->arch.mdcr_el2. As the assembler used to previously mask and preserve MDCR_EL2.HPMN I've had to add a mechanism to save the value of mdcr_el2 as a per-cpu variable during the initialisation code. The kernel never sets this number so we are assuming the bootcode has set up the correct value here. This also moves the conditional setting of the TDA bit from the hyp code into the C code which is currently used for the lazy debug register context switch code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:56 -06:00
static DEFINE_PER_CPU(u32, mdcr_el2);
KVM: arm64: guest debug, add support for single-step This adds support for single-stepping the guest. To do this we need to manipulate the guests PSTATE.SS and MDSCR_EL1.SS bits to trigger stepping. We take care to preserve MDSCR_EL1 and trap access to it to ensure we don't affect the apparent state of the guest. As we have to enable trapping of all software debug exceptions we suppress the ability of the guest to single-step itself. If we didn't we would have to deal with the exception arriving while the guest was in kernelspace when the guest is expecting to single-step userspace. This is something we don't want to unwind in the kernel. Once the host is no longer debugging the guest its ability to single-step userspace is restored. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:58 -06:00
/**
* save/restore_guest_debug_regs
*
* For some debug operations we need to tweak some guest registers. As
* a result we need to save the state of those registers before we
* make those modifications.
*
* Guest access to MDSCR_EL1 is trapped by the hypervisor and handled
* after we have restored the preserved value to the main context.
*/
static void save_guest_debug_regs(struct kvm_vcpu *vcpu)
{
vcpu->arch.guest_debug_preserved.mdscr_el1 = vcpu_sys_reg(vcpu, MDSCR_EL1);
KVM: arm64: add trace points for guest_debug debug 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 <christoffer.dall@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:03 -06:00
trace_kvm_arm_set_dreg32("Saved MDSCR_EL1",
vcpu->arch.guest_debug_preserved.mdscr_el1);
KVM: arm64: guest debug, add support for single-step This adds support for single-stepping the guest. To do this we need to manipulate the guests PSTATE.SS and MDSCR_EL1.SS bits to trigger stepping. We take care to preserve MDSCR_EL1 and trap access to it to ensure we don't affect the apparent state of the guest. As we have to enable trapping of all software debug exceptions we suppress the ability of the guest to single-step itself. If we didn't we would have to deal with the exception arriving while the guest was in kernelspace when the guest is expecting to single-step userspace. This is something we don't want to unwind in the kernel. Once the host is no longer debugging the guest its ability to single-step userspace is restored. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:58 -06:00
}
static void restore_guest_debug_regs(struct kvm_vcpu *vcpu)
{
vcpu_sys_reg(vcpu, MDSCR_EL1) = vcpu->arch.guest_debug_preserved.mdscr_el1;
KVM: arm64: add trace points for guest_debug debug 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 <christoffer.dall@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:03 -06:00
trace_kvm_arm_set_dreg32("Restored MDSCR_EL1",
vcpu_sys_reg(vcpu, MDSCR_EL1));
KVM: arm64: guest debug, add support for single-step This adds support for single-stepping the guest. To do this we need to manipulate the guests PSTATE.SS and MDSCR_EL1.SS bits to trigger stepping. We take care to preserve MDSCR_EL1 and trap access to it to ensure we don't affect the apparent state of the guest. As we have to enable trapping of all software debug exceptions we suppress the ability of the guest to single-step itself. If we didn't we would have to deal with the exception arriving while the guest was in kernelspace when the guest is expecting to single-step userspace. This is something we don't want to unwind in the kernel. Once the host is no longer debugging the guest its ability to single-step userspace is restored. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:58 -06:00
}
KVM: arm: introduce kvm_arm_init/setup/clear_debug This is a precursor for later patches which will need to do more to setup debug state before entering the hyp.S switch code. The existing functionality for setting mdcr_el2 has been moved out of hyp.S and now uses the value kept in vcpu->arch.mdcr_el2. As the assembler used to previously mask and preserve MDCR_EL2.HPMN I've had to add a mechanism to save the value of mdcr_el2 as a per-cpu variable during the initialisation code. The kernel never sets this number so we are assuming the bootcode has set up the correct value here. This also moves the conditional setting of the TDA bit from the hyp code into the C code which is currently used for the lazy debug register context switch code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:56 -06:00
/**
* kvm_arm_init_debug - grab what we need for debug
*
* Currently the sole task of this function is to retrieve the initial
* value of mdcr_el2 so we can preserve MDCR_EL2.HPMN which has
* presumably been set-up by some knowledgeable bootcode.
*
* It is called once per-cpu during CPU hyp initialisation.
*/
void kvm_arm_init_debug(void)
{
__this_cpu_write(mdcr_el2, kvm_call_hyp(__kvm_get_mdcr_el2));
}
KVM: arm64: introduce vcpu->arch.debug_ptr This introduces a level of indirection for the debug registers. Instead of using the sys_regs[] directly we store registers in a structure in the vcpu. The new kvm_arm_reset_debug_ptr() sets the debug ptr to the guest context. Because we no longer give the sys_regs offset for the sys_reg_desc->reg field, but instead the index into a debug-specific struct we need to add a number of additional trap functions for each register. Also as the generic generic user-space access code no longer works we have introduced a new pair of function pointers to the sys_reg_desc structure to override the generic code when needed. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:00 -06:00
/**
* kvm_arm_reset_debug_ptr - reset the debug ptr to point to the vcpu state
*/
void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu)
{
vcpu->arch.debug_ptr = &vcpu->arch.vcpu_debug_state;
}
KVM: arm: introduce kvm_arm_init/setup/clear_debug This is a precursor for later patches which will need to do more to setup debug state before entering the hyp.S switch code. The existing functionality for setting mdcr_el2 has been moved out of hyp.S and now uses the value kept in vcpu->arch.mdcr_el2. As the assembler used to previously mask and preserve MDCR_EL2.HPMN I've had to add a mechanism to save the value of mdcr_el2 as a per-cpu variable during the initialisation code. The kernel never sets this number so we are assuming the bootcode has set up the correct value here. This also moves the conditional setting of the TDA bit from the hyp code into the C code which is currently used for the lazy debug register context switch code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:56 -06:00
/**
* kvm_arm_setup_debug - set up debug related stuff
*
* @vcpu: the vcpu pointer
*
* This is called before each entry into the hypervisor to setup any
* debug related registers. Currently this just ensures we will trap
* access to:
* - Performance monitors (MDCR_EL2_TPM/MDCR_EL2_TPMCR)
* - Debug ROM Address (MDCR_EL2_TDRA)
* - OS related registers (MDCR_EL2_TDOSA)
arm64: KVM: Save/restore the host SPE state when entering/leaving a VM 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 <marc.zyngier@arm.com> Cc: Alex Bennée <alex.bennee@linaro.org> Cc: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-09-22 04:35:43 -06:00
* - Statistical profiler (MDCR_EL2_TPMS/MDCR_EL2_E2PB)
KVM: arm: introduce kvm_arm_init/setup/clear_debug This is a precursor for later patches which will need to do more to setup debug state before entering the hyp.S switch code. The existing functionality for setting mdcr_el2 has been moved out of hyp.S and now uses the value kept in vcpu->arch.mdcr_el2. As the assembler used to previously mask and preserve MDCR_EL2.HPMN I've had to add a mechanism to save the value of mdcr_el2 as a per-cpu variable during the initialisation code. The kernel never sets this number so we are assuming the bootcode has set up the correct value here. This also moves the conditional setting of the TDA bit from the hyp code into the C code which is currently used for the lazy debug register context switch code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:56 -06:00
*
* Additionally, KVM only traps guest accesses to the debug registers if
* the guest is not actively using them (see the KVM_ARM64_DEBUG_DIRTY
* flag on vcpu->arch.debug_flags). Since the guest must not interfere
* with the hardware state when debugging the guest, we must ensure that
* trapping is enabled whenever we are debugging the guest using the
* debug registers.
*/
void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
{
bool trap_debug = !(vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY);
KVM: arm64: add trace points for guest_debug debug 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 <christoffer.dall@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:03 -06:00
trace_kvm_arm_setup_debug(vcpu, vcpu->guest_debug);
arm64: KVM: Save/restore the host SPE state when entering/leaving a VM 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 <marc.zyngier@arm.com> Cc: Alex Bennée <alex.bennee@linaro.org> Cc: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-09-22 04:35:43 -06:00
/*
* This also clears MDCR_EL2_E2PB_MASK to disable guest access
* to the profiling buffer.
*/
KVM: arm: introduce kvm_arm_init/setup/clear_debug This is a precursor for later patches which will need to do more to setup debug state before entering the hyp.S switch code. The existing functionality for setting mdcr_el2 has been moved out of hyp.S and now uses the value kept in vcpu->arch.mdcr_el2. As the assembler used to previously mask and preserve MDCR_EL2.HPMN I've had to add a mechanism to save the value of mdcr_el2 as a per-cpu variable during the initialisation code. The kernel never sets this number so we are assuming the bootcode has set up the correct value here. This also moves the conditional setting of the TDA bit from the hyp code into the C code which is currently used for the lazy debug register context switch code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:56 -06:00
vcpu->arch.mdcr_el2 = __this_cpu_read(mdcr_el2) & MDCR_EL2_HPMN_MASK;
vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM |
arm64: KVM: Save/restore the host SPE state when entering/leaving a VM 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 <marc.zyngier@arm.com> Cc: Alex Bennée <alex.bennee@linaro.org> Cc: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-09-22 04:35:43 -06:00
MDCR_EL2_TPMS |
KVM: arm: introduce kvm_arm_init/setup/clear_debug This is a precursor for later patches which will need to do more to setup debug state before entering the hyp.S switch code. The existing functionality for setting mdcr_el2 has been moved out of hyp.S and now uses the value kept in vcpu->arch.mdcr_el2. As the assembler used to previously mask and preserve MDCR_EL2.HPMN I've had to add a mechanism to save the value of mdcr_el2 as a per-cpu variable during the initialisation code. The kernel never sets this number so we are assuming the bootcode has set up the correct value here. This also moves the conditional setting of the TDA bit from the hyp code into the C code which is currently used for the lazy debug register context switch code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:56 -06:00
MDCR_EL2_TPMCR |
MDCR_EL2_TDRA |
MDCR_EL2_TDOSA);
KVM: arm64: guest debug, add support for single-step This adds support for single-stepping the guest. To do this we need to manipulate the guests PSTATE.SS and MDSCR_EL1.SS bits to trigger stepping. We take care to preserve MDSCR_EL1 and trap access to it to ensure we don't affect the apparent state of the guest. As we have to enable trapping of all software debug exceptions we suppress the ability of the guest to single-step itself. If we didn't we would have to deal with the exception arriving while the guest was in kernelspace when the guest is expecting to single-step userspace. This is something we don't want to unwind in the kernel. Once the host is no longer debugging the guest its ability to single-step userspace is restored. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:58 -06:00
/* Is Guest debugging in effect? */
if (vcpu->guest_debug) {
/* Route all software debug exceptions to EL2 */
KVM: arm64: guest debug, add SW break point support This adds support for SW breakpoints inserted by userspace. We do this by trapping all guest software debug exceptions to the hypervisor (MDCR_EL2.TDE). The exit handler sets an exit reason of KVM_EXIT_DEBUG with the kvm_debug_exit_arch structure holding the exception syndrome information. It will be up to userspace to extract the PC (via GET_ONE_REG) and determine if the debug event was for a breakpoint it inserted. If not userspace will need to re-inject the correct exception restart the hypervisor to deliver the debug exception to the guest. Any other guest software debug exception (e.g. single step or HW assisted breakpoints) will cause an error and the VM to be killed. This is addressed by later patches which add support for the other debug types. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:57 -06:00
vcpu->arch.mdcr_el2 |= MDCR_EL2_TDE;
KVM: arm64: guest debug, add support for single-step This adds support for single-stepping the guest. To do this we need to manipulate the guests PSTATE.SS and MDSCR_EL1.SS bits to trigger stepping. We take care to preserve MDSCR_EL1 and trap access to it to ensure we don't affect the apparent state of the guest. As we have to enable trapping of all software debug exceptions we suppress the ability of the guest to single-step itself. If we didn't we would have to deal with the exception arriving while the guest was in kernelspace when the guest is expecting to single-step userspace. This is something we don't want to unwind in the kernel. Once the host is no longer debugging the guest its ability to single-step userspace is restored. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:58 -06:00
/* Save guest debug state */
save_guest_debug_regs(vcpu);
/*
* Single Step (ARM ARM D2.12.3 The software step state
* machine)
*
* If we are doing Single Step we need to manipulate
* the guest's MDSCR_EL1.SS and PSTATE.SS. Once the
* step has occurred the hypervisor will trap the
* debug exception and we return to userspace.
*
* If the guest attempts to single step its userspace
* we would have to deal with a trapped exception
* while in the guest kernel. Because this would be
* hard to unwind we suppress the guest's ability to
* do so by masking MDSCR_EL.SS.
*
* This confuses guest debuggers which use
* single-step behind the scenes but everything
* returns to normal once the host is no longer
* debugging the system.
*/
if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) {
*vcpu_cpsr(vcpu) |= DBG_SPSR_SS;
vcpu_sys_reg(vcpu, MDSCR_EL1) |= DBG_MDSCR_SS;
} else {
vcpu_sys_reg(vcpu, MDSCR_EL1) &= ~DBG_MDSCR_SS;
}
KVM: arm64: enable KVM_CAP_SET_GUEST_DEBUG Finally advertise the KVM capability for SET_GUEST_DEBUG. Once arm support is added this check can be moved to the common kvm_vm_ioctl_check_extension() code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:02 -06:00
KVM: arm64: add trace points for guest_debug debug 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 <christoffer.dall@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:03 -06:00
trace_kvm_arm_set_dreg32("SPSR_EL2", *vcpu_cpsr(vcpu));
KVM: arm64: enable KVM_CAP_SET_GUEST_DEBUG Finally advertise the KVM capability for SET_GUEST_DEBUG. Once arm support is added this check can be moved to the common kvm_vm_ioctl_check_extension() code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:02 -06:00
/*
* HW Breakpoints and watchpoints
*
* We simply switch the debug_ptr to point to our new
* external_debug_state which has been populated by the
* debug ioctl. The existing KVM_ARM64_DEBUG_DIRTY
* mechanism ensures the registers are updated on the
* world switch.
*/
if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW) {
/* Enable breakpoints/watchpoints */
vcpu_sys_reg(vcpu, MDSCR_EL1) |= DBG_MDSCR_MDE;
vcpu->arch.debug_ptr = &vcpu->arch.external_debug_state;
vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
trap_debug = true;
KVM: arm64: add trace points for guest_debug debug 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 <christoffer.dall@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:03 -06:00
trace_kvm_arm_set_regset("BKPTS", get_num_brps(),
&vcpu->arch.debug_ptr->dbg_bcr[0],
&vcpu->arch.debug_ptr->dbg_bvr[0]);
trace_kvm_arm_set_regset("WAPTS", get_num_wrps(),
&vcpu->arch.debug_ptr->dbg_wcr[0],
&vcpu->arch.debug_ptr->dbg_wvr[0]);
KVM: arm64: enable KVM_CAP_SET_GUEST_DEBUG Finally advertise the KVM capability for SET_GUEST_DEBUG. Once arm support is added this check can be moved to the common kvm_vm_ioctl_check_extension() code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:02 -06:00
}
KVM: arm64: guest debug, add support for single-step This adds support for single-stepping the guest. To do this we need to manipulate the guests PSTATE.SS and MDSCR_EL1.SS bits to trigger stepping. We take care to preserve MDSCR_EL1 and trap access to it to ensure we don't affect the apparent state of the guest. As we have to enable trapping of all software debug exceptions we suppress the ability of the guest to single-step itself. If we didn't we would have to deal with the exception arriving while the guest was in kernelspace when the guest is expecting to single-step userspace. This is something we don't want to unwind in the kernel. Once the host is no longer debugging the guest its ability to single-step userspace is restored. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:58 -06:00
}
KVM: arm64: enable KVM_CAP_SET_GUEST_DEBUG Finally advertise the KVM capability for SET_GUEST_DEBUG. Once arm support is added this check can be moved to the common kvm_vm_ioctl_check_extension() code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:02 -06:00
BUG_ON(!vcpu->guest_debug &&
vcpu->arch.debug_ptr != &vcpu->arch.vcpu_debug_state);
/* Trap debug register access */
if (trap_debug)
vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA;
KVM: arm64: add trace points for guest_debug debug 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 <christoffer.dall@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:03 -06:00
trace_kvm_arm_set_dreg32("MDCR_EL2", vcpu->arch.mdcr_el2);
trace_kvm_arm_set_dreg32("MDSCR_EL1", vcpu_sys_reg(vcpu, MDSCR_EL1));
KVM: arm: introduce kvm_arm_init/setup/clear_debug This is a precursor for later patches which will need to do more to setup debug state before entering the hyp.S switch code. The existing functionality for setting mdcr_el2 has been moved out of hyp.S and now uses the value kept in vcpu->arch.mdcr_el2. As the assembler used to previously mask and preserve MDCR_EL2.HPMN I've had to add a mechanism to save the value of mdcr_el2 as a per-cpu variable during the initialisation code. The kernel never sets this number so we are assuming the bootcode has set up the correct value here. This also moves the conditional setting of the TDA bit from the hyp code into the C code which is currently used for the lazy debug register context switch code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:56 -06:00
}
void kvm_arm_clear_debug(struct kvm_vcpu *vcpu)
{
KVM: arm64: add trace points for guest_debug debug 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 <christoffer.dall@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:03 -06:00
trace_kvm_arm_clear_debug(vcpu->guest_debug);
KVM: arm64: enable KVM_CAP_SET_GUEST_DEBUG Finally advertise the KVM capability for SET_GUEST_DEBUG. Once arm support is added this check can be moved to the common kvm_vm_ioctl_check_extension() code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:02 -06:00
if (vcpu->guest_debug) {
KVM: arm64: guest debug, add support for single-step This adds support for single-stepping the guest. To do this we need to manipulate the guests PSTATE.SS and MDSCR_EL1.SS bits to trigger stepping. We take care to preserve MDSCR_EL1 and trap access to it to ensure we don't affect the apparent state of the guest. As we have to enable trapping of all software debug exceptions we suppress the ability of the guest to single-step itself. If we didn't we would have to deal with the exception arriving while the guest was in kernelspace when the guest is expecting to single-step userspace. This is something we don't want to unwind in the kernel. Once the host is no longer debugging the guest its ability to single-step userspace is restored. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:58 -06:00
restore_guest_debug_regs(vcpu);
KVM: arm64: enable KVM_CAP_SET_GUEST_DEBUG Finally advertise the KVM capability for SET_GUEST_DEBUG. Once arm support is added this check can be moved to the common kvm_vm_ioctl_check_extension() code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:02 -06:00
/*
* If we were using HW debug we need to restore the
* debug_ptr to the guest debug state.
*/
KVM: arm64: add trace points for guest_debug debug 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 <christoffer.dall@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:03 -06:00
if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW) {
KVM: arm64: enable KVM_CAP_SET_GUEST_DEBUG Finally advertise the KVM capability for SET_GUEST_DEBUG. Once arm support is added this check can be moved to the common kvm_vm_ioctl_check_extension() code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:02 -06:00
kvm_arm_reset_debug_ptr(vcpu);
KVM: arm64: add trace points for guest_debug debug 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 <christoffer.dall@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:03 -06:00
trace_kvm_arm_set_regset("BKPTS", get_num_brps(),
&vcpu->arch.debug_ptr->dbg_bcr[0],
&vcpu->arch.debug_ptr->dbg_bvr[0]);
trace_kvm_arm_set_regset("WAPTS", get_num_wrps(),
&vcpu->arch.debug_ptr->dbg_wcr[0],
&vcpu->arch.debug_ptr->dbg_wvr[0]);
}
KVM: arm64: enable KVM_CAP_SET_GUEST_DEBUG Finally advertise the KVM capability for SET_GUEST_DEBUG. Once arm support is added this check can be moved to the common kvm_vm_ioctl_check_extension() code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:30:02 -06:00
}
KVM: arm: introduce kvm_arm_init/setup/clear_debug This is a precursor for later patches which will need to do more to setup debug state before entering the hyp.S switch code. The existing functionality for setting mdcr_el2 has been moved out of hyp.S and now uses the value kept in vcpu->arch.mdcr_el2. As the assembler used to previously mask and preserve MDCR_EL2.HPMN I've had to add a mechanism to save the value of mdcr_el2 as a per-cpu variable during the initialisation code. The kernel never sets this number so we are assuming the bootcode has set up the correct value here. This also moves the conditional setting of the TDA bit from the hyp code into the C code which is currently used for the lazy debug register context switch code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-07-07 10:29:56 -06:00
}
Reference in a new issue Copy permalink