| Message ID | 1427814488-28467-6-git-send-email-alex.bennee@linaro.org |
|---|---|
| State | New |
| Headers | show |
> 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. > > This also moves the conditional setting of the TDA bit from the hyp code > into the C code. > > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > > create mode 100644 arch/arm64/kvm/debug.c > > diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h > index 41008cd..8c01c97 100644 > --- a/arch/arm/include/asm/kvm_host.h > +++ b/arch/arm/include/asm/kvm_host.h > @@ -242,5 +242,7 @@ static inline void kvm_arch_hardware_unsetup(void) {} > static inline void kvm_arch_sync_events(struct kvm *kvm) {} > static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} > static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} > +static inline void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) {} > +static inline void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) {} Do you really want to call these functions "kvm_arch.." although they are not defined for other arch and not triggered by common code? kvm_setup ... or kvm_arm_setup... > > #endif /* __ARM_KVM_HOST_H__ */ > diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c > index 445933d..7ea8b0e 100644 > --- a/arch/arm/kvm/arm.c [...] > +#include <linux/kvm_host.h> > + > +#include <asm/kvm_arm.h> > +#include <asm/kvm_host.h> > + > +/** > + * kvm_arch_setup_debug - set-up debug related stuff > + * > + * @vcpu: the vcpu pointer > + * > + * This is called before each entry in to 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) > + * - Power down debug registers (MDCR_EL2_TDOSA) > + * > + * Additionally the hypervisor lazily saves/restores the debug > + * register state. If it is not currently doing so (arch.debug_flags) > + * then we also need to ensure we trap if the guest messes with them > + * so we know we need to save them. > + */ > + > +void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) > +{ > + vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM | MDCR_EL2_TPMCR); > + vcpu->arch.mdcr_el2 |= (MDCR_EL2_TDRA | MDCR_EL2_TDOSA); I'd put that into a single assignment. > + > + if (!vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY) > + vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA; > + else > + vcpu->arch.mdcr_el2 &= ~MDCR_EL2_TDA; > + > +} > + > +void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) > +{ > + /* Nothing to do yet */ Wonder if that would be the right place to clear MDCR_EL2_TDA unconditionally? But see my comment below. > +} > diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S > index 5befd01..be92bfe1 100644 > --- a/arch/arm64/kvm/hyp.S > +++ b/arch/arm64/kvm/hyp.S > @@ -768,17 +768,8 @@ > mov x2, #(1 << 15) // Trap CP15 Cr=15 > msr hstr_el2, x2 > > - mrs x2, mdcr_el2 > - and x2, x2, #MDCR_EL2_HPMN_MASK > - orr x2, x2, #(MDCR_EL2_TPM | MDCR_EL2_TPMCR) > - orr x2, x2, #(MDCR_EL2_TDRA | MDCR_EL2_TDOSA) > - > - // Check for KVM_ARM64_DEBUG_DIRTY, and set debug to trap > - // if not dirty. > - ldr x3, [x0, #VCPU_DEBUG_FLAGS] > - tbnz x3, #KVM_ARM64_DEBUG_DIRTY_SHIFT, 1f > - orr x2, x2, #MDCR_EL2_TDA > -1: *neither an assembler nor arm expert* The existing code always cleared all bits except MDCR_EL2_HPMN_MASK. So they remained set. We would now always overwrite these bits with the values from vcpu->arch.mdcr_el2, is that okay? > + // Monitor Debug Config - see kvm_arch_setup_debug() > + ldr x2, [x0, #VCPU_MDCR_EL2] > msr mdcr_el2, x2 > .endm > David
On Tue, Mar 31, 2015 at 04:08:03PM +0100, Alex Bennée wrote: > 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. > > This also moves the conditional setting of the TDA bit from the hyp code > into the C code. > > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > > create mode 100644 arch/arm64/kvm/debug.c > > diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h > index 41008cd..8c01c97 100644 > --- a/arch/arm/include/asm/kvm_host.h > +++ b/arch/arm/include/asm/kvm_host.h > @@ -242,5 +242,7 @@ static inline void kvm_arch_hardware_unsetup(void) {} > static inline void kvm_arch_sync_events(struct kvm *kvm) {} > static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} > static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} > +static inline void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) {} > +static inline void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) {} > > #endif /* __ARM_KVM_HOST_H__ */ > diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c > index 445933d..7ea8b0e 100644 > --- a/arch/arm/kvm/arm.c > +++ b/arch/arm/kvm/arm.c > @@ -523,6 +523,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) > > kvm_vgic_flush_hwstate(vcpu); > kvm_timer_flush_hwstate(vcpu); > + kvm_arch_setup_debug(vcpu); > > local_irq_disable(); > > @@ -569,6 +570,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) > * Back from guest > *************************************************************/ > > + kvm_arch_clear_debug(vcpu); > kvm_timer_sync_hwstate(vcpu); > kvm_vgic_sync_hwstate(vcpu); > > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index 8ac3c70..0631840 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -101,6 +101,7 @@ struct kvm_vcpu_arch { > > /* HYP configuration */ > u64 hcr_el2; > + u32 mdcr_el2; > > /* Exception Information */ > struct kvm_vcpu_fault_info fault; > @@ -257,4 +258,7 @@ static inline void kvm_arch_sync_events(struct kvm *kvm) {} > static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} > static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} > > +void kvm_arch_setup_debug(struct kvm_vcpu *vcpu); > +void kvm_arch_clear_debug(struct kvm_vcpu *vcpu); > + > #endif /* __ARM64_KVM_HOST_H__ */ > diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c > index f7fa65d..cd06209 100644 > --- a/arch/arm64/kernel/asm-offsets.c > +++ b/arch/arm64/kernel/asm-offsets.c > @@ -122,6 +122,7 @@ int main(void) > DEFINE(VCPU_HPFAR_EL2, offsetof(struct kvm_vcpu, arch.fault.hpfar_el2)); > DEFINE(VCPU_DEBUG_FLAGS, offsetof(struct kvm_vcpu, arch.debug_flags)); > DEFINE(VCPU_HCR_EL2, offsetof(struct kvm_vcpu, arch.hcr_el2)); > + DEFINE(VCPU_MDCR_EL2, offsetof(struct kvm_vcpu, arch.mdcr_el2)); > DEFINE(VCPU_IRQ_LINES, offsetof(struct kvm_vcpu, arch.irq_lines)); > DEFINE(VCPU_HOST_CONTEXT, offsetof(struct kvm_vcpu, arch.host_cpu_context)); > DEFINE(VCPU_TIMER_CNTV_CTL, offsetof(struct kvm_vcpu, arch.timer_cpu.cntv_ctl)); > diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile > index 4e6e09e..6796d4a 100644 > --- a/arch/arm64/kvm/Makefile > +++ b/arch/arm64/kvm/Makefile > @@ -17,7 +17,7 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(ARM)/psci.o $(ARM)/perf.o > > kvm-$(CONFIG_KVM_ARM_HOST) += emulate.o inject_fault.o regmap.o > kvm-$(CONFIG_KVM_ARM_HOST) += hyp.o hyp-init.o handle_exit.o > -kvm-$(CONFIG_KVM_ARM_HOST) += guest.o reset.o sys_regs.o sys_regs_generic_v8.o > +kvm-$(CONFIG_KVM_ARM_HOST) += guest.o debug.o reset.o sys_regs.o sys_regs_generic_v8.o > > kvm-$(CONFIG_KVM_ARM_VGIC) += $(KVM)/arm/vgic.o > kvm-$(CONFIG_KVM_ARM_VGIC) += $(KVM)/arm/vgic-v2.o > diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c > new file mode 100644 > index 0000000..8a29d0b > --- /dev/null > +++ b/arch/arm64/kvm/debug.c > @@ -0,0 +1,58 @@ > +/* > + * 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> > + > +#include <asm/kvm_arm.h> > +#include <asm/kvm_host.h> linux/kvm_host.h added above includes this asm/kvm_host already > + > +/** > + * kvm_arch_setup_debug - set-up debug related stuff > + * > + * @vcpu: the vcpu pointer > + * > + * This is called before each entry in to the hypervisor to setup any into > + * 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) > + * - Power down debug registers (MDCR_EL2_TDOSA) > + * > + * Additionally the hypervisor lazily saves/restores the debug > + * register state. If it is not currently doing so (arch.debug_flags) > + * then we also need to ensure we trap if the guest messes with them > + * so we know we need to save them. > + */ > + > +void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) > +{ > + vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM | MDCR_EL2_TPMCR); > + vcpu->arch.mdcr_el2 |= (MDCR_EL2_TDRA | MDCR_EL2_TDOSA); > + > + if (!vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY) missing () in the if (!(x & y)) condition > + vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA; > + else > + vcpu->arch.mdcr_el2 &= ~MDCR_EL2_TDA; > + > +} > + > +void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) > +{ > + /* Nothing to do yet */ > +} > diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S > index 5befd01..be92bfe1 100644 > --- a/arch/arm64/kvm/hyp.S > +++ b/arch/arm64/kvm/hyp.S > @@ -768,17 +768,8 @@ > mov x2, #(1 << 15) // Trap CP15 Cr=15 > msr hstr_el2, x2 > > - mrs x2, mdcr_el2 > - and x2, x2, #MDCR_EL2_HPMN_MASK > - orr x2, x2, #(MDCR_EL2_TPM | MDCR_EL2_TPMCR) > - orr x2, x2, #(MDCR_EL2_TDRA | MDCR_EL2_TDOSA) > - > - // Check for KVM_ARM64_DEBUG_DIRTY, and set debug to trap > - // if not dirty. > - ldr x3, [x0, #VCPU_DEBUG_FLAGS] > - tbnz x3, #KVM_ARM64_DEBUG_DIRTY_SHIFT, 1f > - orr x2, x2, #MDCR_EL2_TDA > -1: > + // Monitor Debug Config - see kvm_arch_setup_debug() > + ldr x2, [x0, #VCPU_MDCR_EL2] > msr mdcr_el2, x2 > .endm We lose the preservation of HPMN, as I see David points out as well. Based on the ARM ARM setting it to zero is most likely wrong, as that results in constrained unpredictable behavior. drew
On Wed, Apr 01, 2015 at 06:28:55PM +0200, David Hildenbrand wrote: > > 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. > > > > This also moves the conditional setting of the TDA bit from the hyp code > > into the C code. > > > > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > > > > create mode 100644 arch/arm64/kvm/debug.c > > > > diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h > > index 41008cd..8c01c97 100644 > > --- a/arch/arm/include/asm/kvm_host.h > > +++ b/arch/arm/include/asm/kvm_host.h > > @@ -242,5 +242,7 @@ static inline void kvm_arch_hardware_unsetup(void) {} > > static inline void kvm_arch_sync_events(struct kvm *kvm) {} > > static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} > > static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} > > +static inline void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) {} > > +static inline void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) {} > > Do you really want to call these functions "kvm_arch.." although they are not > defined for other arch and not triggered by common code? > Agreed. If other arches want something similar we can rename/refactor later. If these are arm-only functions, then we don't need the generic prefix, which is actually even a bit confusing. drew
Andrew Jones <drjones@redhat.com> writes: > On Wed, Apr 01, 2015 at 06:28:55PM +0200, David Hildenbrand wrote: >> > 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. >> > >> > This also moves the conditional setting of the TDA bit from the hyp code >> > into the C code. >> > >> > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> >> > >> > create mode 100644 arch/arm64/kvm/debug.c >> > >> > diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h >> > index 41008cd..8c01c97 100644 >> > --- a/arch/arm/include/asm/kvm_host.h >> > +++ b/arch/arm/include/asm/kvm_host.h >> > @@ -242,5 +242,7 @@ static inline void kvm_arch_hardware_unsetup(void) {} >> > static inline void kvm_arch_sync_events(struct kvm *kvm) {} >> > static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} >> > static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} >> > +static inline void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) {} >> > +static inline void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) {} >> >> Do you really want to call these functions "kvm_arch.." although they are not >> defined for other arch and not triggered by common code? >> > > Agreed. If other arches want something similar we can rename/refactor > later. If these are arm-only functions, then we don't need the generic > prefix, which is actually even a bit confusing. They are arm only but I was keeping in mind the need to add guest debug to ARMv7 at some point. > > drew
On Tue, Mar 31, 2015 at 04:08:03PM +0100, Alex Bennée wrote: > 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. > > This also moves the conditional setting of the TDA bit from the hyp code > into the C code. > > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > > create mode 100644 arch/arm64/kvm/debug.c > > diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h > index 41008cd..8c01c97 100644 > --- a/arch/arm/include/asm/kvm_host.h > +++ b/arch/arm/include/asm/kvm_host.h > @@ -242,5 +242,7 @@ static inline void kvm_arch_hardware_unsetup(void) {} > static inline void kvm_arch_sync_events(struct kvm *kvm) {} > static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} > static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} > +static inline void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) {} > +static inline void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) {} > > #endif /* __ARM_KVM_HOST_H__ */ > diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c > index 445933d..7ea8b0e 100644 > --- a/arch/arm/kvm/arm.c > +++ b/arch/arm/kvm/arm.c > @@ -523,6 +523,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) > > kvm_vgic_flush_hwstate(vcpu); > kvm_timer_flush_hwstate(vcpu); > + kvm_arch_setup_debug(vcpu); > > local_irq_disable(); > > @@ -569,6 +570,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) > * Back from guest > *************************************************************/ > > + kvm_arch_clear_debug(vcpu); > kvm_timer_sync_hwstate(vcpu); > kvm_vgic_sync_hwstate(vcpu); > > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index 8ac3c70..0631840 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -101,6 +101,7 @@ struct kvm_vcpu_arch { > > /* HYP configuration */ > u64 hcr_el2; > + u32 mdcr_el2; > > /* Exception Information */ > struct kvm_vcpu_fault_info fault; > @@ -257,4 +258,7 @@ static inline void kvm_arch_sync_events(struct kvm *kvm) {} > static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} > static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} > > +void kvm_arch_setup_debug(struct kvm_vcpu *vcpu); > +void kvm_arch_clear_debug(struct kvm_vcpu *vcpu); > + > #endif /* __ARM64_KVM_HOST_H__ */ > diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c > index f7fa65d..cd06209 100644 > --- a/arch/arm64/kernel/asm-offsets.c > +++ b/arch/arm64/kernel/asm-offsets.c > @@ -122,6 +122,7 @@ int main(void) > DEFINE(VCPU_HPFAR_EL2, offsetof(struct kvm_vcpu, arch.fault.hpfar_el2)); > DEFINE(VCPU_DEBUG_FLAGS, offsetof(struct kvm_vcpu, arch.debug_flags)); > DEFINE(VCPU_HCR_EL2, offsetof(struct kvm_vcpu, arch.hcr_el2)); > + DEFINE(VCPU_MDCR_EL2, offsetof(struct kvm_vcpu, arch.mdcr_el2)); > DEFINE(VCPU_IRQ_LINES, offsetof(struct kvm_vcpu, arch.irq_lines)); > DEFINE(VCPU_HOST_CONTEXT, offsetof(struct kvm_vcpu, arch.host_cpu_context)); > DEFINE(VCPU_TIMER_CNTV_CTL, offsetof(struct kvm_vcpu, arch.timer_cpu.cntv_ctl)); > diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile > index 4e6e09e..6796d4a 100644 > --- a/arch/arm64/kvm/Makefile > +++ b/arch/arm64/kvm/Makefile > @@ -17,7 +17,7 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(ARM)/psci.o $(ARM)/perf.o > > kvm-$(CONFIG_KVM_ARM_HOST) += emulate.o inject_fault.o regmap.o > kvm-$(CONFIG_KVM_ARM_HOST) += hyp.o hyp-init.o handle_exit.o > -kvm-$(CONFIG_KVM_ARM_HOST) += guest.o reset.o sys_regs.o sys_regs_generic_v8.o > +kvm-$(CONFIG_KVM_ARM_HOST) += guest.o debug.o reset.o sys_regs.o sys_regs_generic_v8.o > > kvm-$(CONFIG_KVM_ARM_VGIC) += $(KVM)/arm/vgic.o > kvm-$(CONFIG_KVM_ARM_VGIC) += $(KVM)/arm/vgic-v2.o > diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c > new file mode 100644 > index 0000000..8a29d0b > --- /dev/null > +++ b/arch/arm64/kvm/debug.c > @@ -0,0 +1,58 @@ > +/* > + * 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> > + > +#include <asm/kvm_arm.h> > +#include <asm/kvm_host.h> > + > +/** > + * kvm_arch_setup_debug - set-up debug related stuff nit: I think you want "set up" when it's a verb. > + * > + * @vcpu: the vcpu pointer > + * > + * This is called before each entry in to the hypervisor to setup any s/in to/into/ s/setup/set up/ > + * debug related registers. Currently this just ensures we will trap > + * access to: guest accesses to: > + * - Performance monitors (MDCR_EL2_TPM/MDCR_EL2_TPMCR) > + * - Debug ROM Address (MDCR_EL2_TDRA) > + * - Power down debug registers (MDCR_EL2_TDOSA) > + * > + * Additionally the hypervisor lazily saves/restores the debug > + * register state. If it is not currently doing so (arch.debug_flags) > + * then we also need to ensure we trap if the guest messes with them > + * so we know we need to save them. This paragraph is a little hard to make sense of. If I understand it correctly, the point is that when debugging the guest we need to make sure guest accesses to the debug registers traps? If so, I would suggest something like: 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. > + */ > + > +void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) > +{ > + vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM | MDCR_EL2_TPMCR); > + vcpu->arch.mdcr_el2 |= (MDCR_EL2_TDRA | MDCR_EL2_TDOSA); > + > + if (!vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY) > + vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA; > + else > + vcpu->arch.mdcr_el2 &= ~MDCR_EL2_TDA; > + > +} > + > +void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) > +{ > + /* Nothing to do yet */ > +} > diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S > index 5befd01..be92bfe1 100644 > --- a/arch/arm64/kvm/hyp.S > +++ b/arch/arm64/kvm/hyp.S > @@ -768,17 +768,8 @@ > mov x2, #(1 << 15) // Trap CP15 Cr=15 > msr hstr_el2, x2 > > - mrs x2, mdcr_el2 > - and x2, x2, #MDCR_EL2_HPMN_MASK > - orr x2, x2, #(MDCR_EL2_TPM | MDCR_EL2_TPMCR) > - orr x2, x2, #(MDCR_EL2_TDRA | MDCR_EL2_TDOSA) > - > - // Check for KVM_ARM64_DEBUG_DIRTY, and set debug to trap > - // if not dirty. > - ldr x3, [x0, #VCPU_DEBUG_FLAGS] > - tbnz x3, #KVM_ARM64_DEBUG_DIRTY_SHIFT, 1f > - orr x2, x2, #MDCR_EL2_TDA > -1: > + // Monitor Debug Config - see kvm_arch_setup_debug() > + ldr x2, [x0, #VCPU_MDCR_EL2] > msr mdcr_el2, x2 > .endm > As the other reviewers noted, this is now setting the number of PMU counters accessible to 0. I'm fine with always setting mdcr_el2 from memory, but I think we need to add code in hyp-init.S to read PMCR_EL0.N and store that in a per-cpu (not vcpu) variable and configure mdcr_el2 using that value in kvm_arch_set_debug(), but then you need to call kvm_arch_set_debug() from a non-preemptible section, which is probably a good idea anyway. Note that I couldn't see that we are initializing MDCR_EL2 anywhere, so that should probably be a separate fix. Thanks, -Christoffer
On Mon, Apr 13, 2015 at 04:36:23PM +0200, Christoffer Dall wrote: [...] > > + > > +/** > > + * kvm_arch_setup_debug - set-up debug related stuff > > nit: I think you want "set up" when it's a verb. > > > + * > > + * @vcpu: the vcpu pointer > > + * > > + * This is called before each entry in to the hypervisor to setup any > > s/in to/into/ > s/setup/set up/ > > > + * debug related registers. Currently this just ensures we will trap > > + * access to: > > guest accesses to: > > > + * - Performance monitors (MDCR_EL2_TPM/MDCR_EL2_TPMCR) > > + * - Debug ROM Address (MDCR_EL2_TDRA) > > + * - Power down debug registers (MDCR_EL2_TDOSA) > > + * > > + * Additionally the hypervisor lazily saves/restores the debug > > + * register state. If it is not currently doing so (arch.debug_flags) > > + * then we also need to ensure we trap if the guest messes with them > > + * so we know we need to save them. > > This paragraph is a little hard to make sense of. If I understand it > correctly, the point is that when debugging the guest we need to make > sure guest accesses to the debug registers traps? If so, I would > suggest something like: > > 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. > thinking about this, I don't think we're enforcing this yet, but maybe that will come in the later patches or I misread the original paragraph. -Christoffer
Christoffer Dall <christoffer.dall@linaro.org> writes: > On Tue, Mar 31, 2015 at 04:08:03PM +0100, Alex Bennée wrote: >> 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. >> >> This also moves the conditional setting of the TDA bit from the hyp code >> into the C code. >> >> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> >> >> create mode 100644 arch/arm64/kvm/debug.c >> >> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h >> index 41008cd..8c01c97 100644 >> --- a/arch/arm/include/asm/kvm_host.h >> +++ b/arch/arm/include/asm/kvm_host.h >> @@ -242,5 +242,7 @@ static inline void kvm_arch_hardware_unsetup(void) {} >> static inline void kvm_arch_sync_events(struct kvm *kvm) {} >> static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} >> static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} >> +static inline void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) {} >> +static inline void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) {} >> >> #endif /* __ARM_KVM_HOST_H__ */ >> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c >> index 445933d..7ea8b0e 100644 >> --- a/arch/arm/kvm/arm.c >> +++ b/arch/arm/kvm/arm.c >> @@ -523,6 +523,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) >> >> kvm_vgic_flush_hwstate(vcpu); >> kvm_timer_flush_hwstate(vcpu); >> + kvm_arch_setup_debug(vcpu); >> >> local_irq_disable(); >> >> @@ -569,6 +570,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) >> * Back from guest >> *************************************************************/ >> >> + kvm_arch_clear_debug(vcpu); >> kvm_timer_sync_hwstate(vcpu); >> kvm_vgic_sync_hwstate(vcpu); >> >> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h >> index 8ac3c70..0631840 100644 >> --- a/arch/arm64/include/asm/kvm_host.h >> +++ b/arch/arm64/include/asm/kvm_host.h >> @@ -101,6 +101,7 @@ struct kvm_vcpu_arch { >> >> /* HYP configuration */ >> u64 hcr_el2; >> + u32 mdcr_el2; >> >> /* Exception Information */ >> struct kvm_vcpu_fault_info fault; >> @@ -257,4 +258,7 @@ static inline void kvm_arch_sync_events(struct kvm *kvm) {} >> static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} >> static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} >> >> +void kvm_arch_setup_debug(struct kvm_vcpu *vcpu); >> +void kvm_arch_clear_debug(struct kvm_vcpu *vcpu); >> + >> #endif /* __ARM64_KVM_HOST_H__ */ >> diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c >> index f7fa65d..cd06209 100644 >> --- a/arch/arm64/kernel/asm-offsets.c >> +++ b/arch/arm64/kernel/asm-offsets.c >> @@ -122,6 +122,7 @@ int main(void) >> DEFINE(VCPU_HPFAR_EL2, offsetof(struct kvm_vcpu, arch.fault.hpfar_el2)); >> DEFINE(VCPU_DEBUG_FLAGS, offsetof(struct kvm_vcpu, arch.debug_flags)); >> DEFINE(VCPU_HCR_EL2, offsetof(struct kvm_vcpu, arch.hcr_el2)); >> + DEFINE(VCPU_MDCR_EL2, offsetof(struct kvm_vcpu, arch.mdcr_el2)); >> DEFINE(VCPU_IRQ_LINES, offsetof(struct kvm_vcpu, arch.irq_lines)); >> DEFINE(VCPU_HOST_CONTEXT, offsetof(struct kvm_vcpu, arch.host_cpu_context)); >> DEFINE(VCPU_TIMER_CNTV_CTL, offsetof(struct kvm_vcpu, arch.timer_cpu.cntv_ctl)); >> diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile >> index 4e6e09e..6796d4a 100644 >> --- a/arch/arm64/kvm/Makefile >> +++ b/arch/arm64/kvm/Makefile >> @@ -17,7 +17,7 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(ARM)/psci.o $(ARM)/perf.o >> >> kvm-$(CONFIG_KVM_ARM_HOST) += emulate.o inject_fault.o regmap.o >> kvm-$(CONFIG_KVM_ARM_HOST) += hyp.o hyp-init.o handle_exit.o >> -kvm-$(CONFIG_KVM_ARM_HOST) += guest.o reset.o sys_regs.o sys_regs_generic_v8.o >> +kvm-$(CONFIG_KVM_ARM_HOST) += guest.o debug.o reset.o sys_regs.o sys_regs_generic_v8.o >> >> kvm-$(CONFIG_KVM_ARM_VGIC) += $(KVM)/arm/vgic.o >> kvm-$(CONFIG_KVM_ARM_VGIC) += $(KVM)/arm/vgic-v2.o >> diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c >> new file mode 100644 >> index 0000000..8a29d0b >> --- /dev/null >> +++ b/arch/arm64/kvm/debug.c >> @@ -0,0 +1,58 @@ >> +/* >> + * 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> >> + >> +#include <asm/kvm_arm.h> >> +#include <asm/kvm_host.h> >> + >> +/** >> + * kvm_arch_setup_debug - set-up debug related stuff > > nit: I think you want "set up" when it's a verb. > >> + * >> + * @vcpu: the vcpu pointer >> + * >> + * This is called before each entry in to the hypervisor to setup any > > s/in to/into/ > s/setup/set up/ > >> + * debug related registers. Currently this just ensures we will trap >> + * access to: > > guest accesses to: > >> + * - Performance monitors (MDCR_EL2_TPM/MDCR_EL2_TPMCR) >> + * - Debug ROM Address (MDCR_EL2_TDRA) >> + * - Power down debug registers (MDCR_EL2_TDOSA) >> + * >> + * Additionally the hypervisor lazily saves/restores the debug >> + * register state. If it is not currently doing so (arch.debug_flags) >> + * then we also need to ensure we trap if the guest messes with them >> + * so we know we need to save them. > > This paragraph is a little hard to make sense of. If I understand it > correctly, the point is that when debugging the guest we need to make > sure guest accesses to the debug registers traps? If so, I would > suggest something like: > > 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. > >> + */ >> + >> +void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) >> +{ >> + vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM | MDCR_EL2_TPMCR); >> + vcpu->arch.mdcr_el2 |= (MDCR_EL2_TDRA | MDCR_EL2_TDOSA); >> + >> + if (!vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY) >> + vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA; >> + else >> + vcpu->arch.mdcr_el2 &= ~MDCR_EL2_TDA; >> + >> +} >> + >> +void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) >> +{ >> + /* Nothing to do yet */ >> +} >> diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S >> index 5befd01..be92bfe1 100644 >> --- a/arch/arm64/kvm/hyp.S >> +++ b/arch/arm64/kvm/hyp.S >> @@ -768,17 +768,8 @@ >> mov x2, #(1 << 15) // Trap CP15 Cr=15 >> msr hstr_el2, x2 >> >> - mrs x2, mdcr_el2 >> - and x2, x2, #MDCR_EL2_HPMN_MASK >> - orr x2, x2, #(MDCR_EL2_TPM | MDCR_EL2_TPMCR) >> - orr x2, x2, #(MDCR_EL2_TDRA | MDCR_EL2_TDOSA) >> - >> - // Check for KVM_ARM64_DEBUG_DIRTY, and set debug to trap >> - // if not dirty. >> - ldr x3, [x0, #VCPU_DEBUG_FLAGS] >> - tbnz x3, #KVM_ARM64_DEBUG_DIRTY_SHIFT, 1f >> - orr x2, x2, #MDCR_EL2_TDA >> -1: >> + // Monitor Debug Config - see kvm_arch_setup_debug() >> + ldr x2, [x0, #VCPU_MDCR_EL2] >> msr mdcr_el2, x2 >> .endm >> > > As the other reviewers noted, this is now setting the number of PMU > counters accessible to 0. I'm fine with always setting mdcr_el2 from > memory, but I think we need to add code in hyp-init.S to read PMCR_EL0.N > and store that in a per-cpu (not vcpu) variable and configure mdcr_el2 > using that value in kvm_arch_set_debug(), but then you need to call > kvm_arch_set_debug() from a non-preemptible section, which is probably a > good idea anyway. Note that I couldn't see that we are initializing > MDCR_EL2 anywhere, so that should probably be a separate fix. Yeah because I couldn't see it being set I figured it was OK to blat it with zeros. But you are right we should set it up properly if we are going to mess with it. > > Thanks, > -Christoffer
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index 41008cd..8c01c97 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -242,5 +242,7 @@ static inline void kvm_arch_hardware_unsetup(void) {} static inline void kvm_arch_sync_events(struct kvm *kvm) {} static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} +static inline void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) {} +static inline void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) {} #endif /* __ARM_KVM_HOST_H__ */ diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index 445933d..7ea8b0e 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -523,6 +523,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) kvm_vgic_flush_hwstate(vcpu); kvm_timer_flush_hwstate(vcpu); + kvm_arch_setup_debug(vcpu); local_irq_disable(); @@ -569,6 +570,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) * Back from guest *************************************************************/ + kvm_arch_clear_debug(vcpu); kvm_timer_sync_hwstate(vcpu); kvm_vgic_sync_hwstate(vcpu); diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 8ac3c70..0631840 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -101,6 +101,7 @@ struct kvm_vcpu_arch { /* HYP configuration */ u64 hcr_el2; + u32 mdcr_el2; /* Exception Information */ struct kvm_vcpu_fault_info fault; @@ -257,4 +258,7 @@ static inline void kvm_arch_sync_events(struct kvm *kvm) {} static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} +void kvm_arch_setup_debug(struct kvm_vcpu *vcpu); +void kvm_arch_clear_debug(struct kvm_vcpu *vcpu); + #endif /* __ARM64_KVM_HOST_H__ */ diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c index f7fa65d..cd06209 100644 --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -122,6 +122,7 @@ int main(void) DEFINE(VCPU_HPFAR_EL2, offsetof(struct kvm_vcpu, arch.fault.hpfar_el2)); DEFINE(VCPU_DEBUG_FLAGS, offsetof(struct kvm_vcpu, arch.debug_flags)); DEFINE(VCPU_HCR_EL2, offsetof(struct kvm_vcpu, arch.hcr_el2)); + DEFINE(VCPU_MDCR_EL2, offsetof(struct kvm_vcpu, arch.mdcr_el2)); DEFINE(VCPU_IRQ_LINES, offsetof(struct kvm_vcpu, arch.irq_lines)); DEFINE(VCPU_HOST_CONTEXT, offsetof(struct kvm_vcpu, arch.host_cpu_context)); DEFINE(VCPU_TIMER_CNTV_CTL, offsetof(struct kvm_vcpu, arch.timer_cpu.cntv_ctl)); diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile index 4e6e09e..6796d4a 100644 --- a/arch/arm64/kvm/Makefile +++ b/arch/arm64/kvm/Makefile @@ -17,7 +17,7 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(ARM)/psci.o $(ARM)/perf.o kvm-$(CONFIG_KVM_ARM_HOST) += emulate.o inject_fault.o regmap.o kvm-$(CONFIG_KVM_ARM_HOST) += hyp.o hyp-init.o handle_exit.o -kvm-$(CONFIG_KVM_ARM_HOST) += guest.o reset.o sys_regs.o sys_regs_generic_v8.o +kvm-$(CONFIG_KVM_ARM_HOST) += guest.o debug.o reset.o sys_regs.o sys_regs_generic_v8.o kvm-$(CONFIG_KVM_ARM_VGIC) += $(KVM)/arm/vgic.o kvm-$(CONFIG_KVM_ARM_VGIC) += $(KVM)/arm/vgic-v2.o diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c new file mode 100644 index 0000000..8a29d0b --- /dev/null +++ b/arch/arm64/kvm/debug.c @@ -0,0 +1,58 @@ +/* + * 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> + +#include <asm/kvm_arm.h> +#include <asm/kvm_host.h> + +/** + * kvm_arch_setup_debug - set-up debug related stuff + * + * @vcpu: the vcpu pointer + * + * This is called before each entry in to 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) + * - Power down debug registers (MDCR_EL2_TDOSA) + * + * Additionally the hypervisor lazily saves/restores the debug + * register state. If it is not currently doing so (arch.debug_flags) + * then we also need to ensure we trap if the guest messes with them + * so we know we need to save them. + */ + +void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) +{ + vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM | MDCR_EL2_TPMCR); + vcpu->arch.mdcr_el2 |= (MDCR_EL2_TDRA | MDCR_EL2_TDOSA); + + if (!vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY) + vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA; + else + vcpu->arch.mdcr_el2 &= ~MDCR_EL2_TDA; + +} + +void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) +{ + /* Nothing to do yet */ +} diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S index 5befd01..be92bfe1 100644 --- a/arch/arm64/kvm/hyp.S +++ b/arch/arm64/kvm/hyp.S @@ -768,17 +768,8 @@ mov x2, #(1 << 15) // Trap CP15 Cr=15 msr hstr_el2, x2 - mrs x2, mdcr_el2 - and x2, x2, #MDCR_EL2_HPMN_MASK - orr x2, x2, #(MDCR_EL2_TPM | MDCR_EL2_TPMCR) - orr x2, x2, #(MDCR_EL2_TDRA | MDCR_EL2_TDOSA) - - // Check for KVM_ARM64_DEBUG_DIRTY, and set debug to trap - // if not dirty. - ldr x3, [x0, #VCPU_DEBUG_FLAGS] - tbnz x3, #KVM_ARM64_DEBUG_DIRTY_SHIFT, 1f - orr x2, x2, #MDCR_EL2_TDA -1: + // Monitor Debug Config - see kvm_arch_setup_debug() + ldr x2, [x0, #VCPU_MDCR_EL2] msr mdcr_el2, x2 .endm
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. This also moves the conditional setting of the TDA bit from the hyp code into the C code. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> create mode 100644 arch/arm64/kvm/debug.c