| Message ID | 1430929407-3487-6-git-send-email-alex.bennee@linaro.org |
|---|---|
| State | New |
| Headers | show |
On Wed, May 06, 2015 at 05:23:20PM +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. > > 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> > > --- > v3 > - rename fns from arch->arm > - preserve MDCR_EL2.HPMN setting > - re-word some of the comments > - fix some minor grammar nits > - merge setting of mdcr_el2 > - introduce trap_debug flag > - move setup/clear within the irq lock section > > 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 d71607c..746c0c69 100644 > --- a/arch/arm/include/asm/kvm_host.h > +++ b/arch/arm/include/asm/kvm_host.h > @@ -236,4 +236,8 @@ 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_arm_init_debug(void) {} > +static inline void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) {} > +static inline void kvm_arm_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 52a1d4d38..4a274e1 100644 > --- a/arch/arm/kvm/arm.c > +++ b/arch/arm/kvm/arm.c > @@ -570,6 +570,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) > continue; > } > > + kvm_arm_setup_debug(vcpu); > + > /************************************************************** > * Enter the guest > */ > @@ -582,7 +584,10 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) > vcpu->mode = OUTSIDE_GUEST_MODE; > kvm_guest_exit(); > trace_kvm_exit(kvm_vcpu_trap_get_class(vcpu), *vcpu_pc(vcpu)); > - /* > + > + kvm_arm_clear_debug(vcpu); > + > + /* > * We may have taken a host interrupt in HYP mode (ie > * while executing the guest). This interrupt is still > * pending, as we haven't serviced it yet! > @@ -930,6 +935,8 @@ static void cpu_init_hyp_mode(void *dummy) > vector_ptr = (unsigned long)__kvm_hyp_vector; > > __cpu_init_hyp_mode(boot_pgd_ptr, pgd_ptr, hyp_stack_ptr, vector_ptr); > + > + kvm_arm_init_debug(); > } > > static int hyp_init_cpu_notify(struct notifier_block *self, > diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h > index 4f7310f..d6b507e 100644 > --- a/arch/arm64/include/asm/kvm_asm.h > +++ b/arch/arm64/include/asm/kvm_asm.h > @@ -137,6 +137,8 @@ extern char __restore_vgic_v2_state[]; > extern char __save_vgic_v3_state[]; > extern char __restore_vgic_v3_state[]; > > +extern u32 __kvm_get_mdcr_el2(void); > + > #endif > > #endif /* __ARM_KVM_ASM_H__ */ > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index f0f58c9..7cb99b5 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -103,6 +103,7 @@ struct kvm_vcpu_arch { > > /* HYP configuration */ > u64 hcr_el2; > + u32 mdcr_el2; > > /* Exception Information */ > struct kvm_vcpu_fault_info fault; > @@ -250,4 +251,8 @@ 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_arm_init_debug(void); > +void kvm_arm_setup_debug(struct kvm_vcpu *vcpu); > +void kvm_arm_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 da675cc..dfb25a2 100644 > --- a/arch/arm64/kernel/asm-offsets.c > +++ b/arch/arm64/kernel/asm-offsets.c > @@ -117,6 +117,7 @@ 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 d5904f8..90e3f39 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_HOST) += $(KVM)/arm/vgic.o > kvm-$(CONFIG_KVM_ARM_HOST) += $(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..b1f8731 > --- /dev/null > +++ b/arch/arm64/kvm/debug.c > @@ -0,0 +1,83 @@ > +/* > + * 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> > + > +static DEFINE_PER_CPU(u32, mdcr_el2); > + > +/** > + * 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_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) > + * - Power down debug registers (MDCR_EL2_TDOSA) TDOSA traps more than the DBGPRCR_EL1 register, so "OS-related registers" is probably what you want here. > + * > + * 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); > + > + vcpu->arch.mdcr_el2 = __this_cpu_read(mdcr_el2) & MDCR_EL2_HPMN_MASK; > + vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM | > + MDCR_EL2_TPMCR | > + MDCR_EL2_TDRA | > + MDCR_EL2_TDOSA); > + > + /* Trap on access to debug registers? */ > + if (trap_debug) > + vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA; > + else > + vcpu->arch.mdcr_el2 &= ~MDCR_EL2_TDA; the else-clause shouldn't be necessary as you've just initialized the register with the HPMN_MASK. > + > +} > + > +void kvm_arm_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..15159aa 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() kvm_arm_setup_debug() ? > + ldr x2, [x0, #VCPU_MDCR_EL2] > msr mdcr_el2, x2 > .endm > > @@ -1295,4 +1286,10 @@ ENTRY(__kvm_hyp_vector) > ventry el1_error_invalid // Error 32-bit EL1 > ENDPROC(__kvm_hyp_vector) > > + > +ENTRY(__kvm_get_mdcr_el2) > + mrs x0, mdcr_el2 > + ret > +ENDPROC(__kvm_get_mdcr_el2) > + > .popsection > -- > 2.3.5 > Thanks, -Christoffer -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index d71607c..746c0c69 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -236,4 +236,8 @@ 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_arm_init_debug(void) {} +static inline void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) {} +static inline void kvm_arm_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 52a1d4d38..4a274e1 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -570,6 +570,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) continue; } + kvm_arm_setup_debug(vcpu); + /************************************************************** * Enter the guest */ @@ -582,7 +584,10 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) vcpu->mode = OUTSIDE_GUEST_MODE; kvm_guest_exit(); trace_kvm_exit(kvm_vcpu_trap_get_class(vcpu), *vcpu_pc(vcpu)); - /* + + kvm_arm_clear_debug(vcpu); + + /* * We may have taken a host interrupt in HYP mode (ie * while executing the guest). This interrupt is still * pending, as we haven't serviced it yet! @@ -930,6 +935,8 @@ static void cpu_init_hyp_mode(void *dummy) vector_ptr = (unsigned long)__kvm_hyp_vector; __cpu_init_hyp_mode(boot_pgd_ptr, pgd_ptr, hyp_stack_ptr, vector_ptr); + + kvm_arm_init_debug(); } static int hyp_init_cpu_notify(struct notifier_block *self, diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index 4f7310f..d6b507e 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -137,6 +137,8 @@ extern char __restore_vgic_v2_state[]; extern char __save_vgic_v3_state[]; extern char __restore_vgic_v3_state[]; +extern u32 __kvm_get_mdcr_el2(void); + #endif #endif /* __ARM_KVM_ASM_H__ */ diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index f0f58c9..7cb99b5 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -103,6 +103,7 @@ struct kvm_vcpu_arch { /* HYP configuration */ u64 hcr_el2; + u32 mdcr_el2; /* Exception Information */ struct kvm_vcpu_fault_info fault; @@ -250,4 +251,8 @@ 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_arm_init_debug(void); +void kvm_arm_setup_debug(struct kvm_vcpu *vcpu); +void kvm_arm_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 da675cc..dfb25a2 100644 --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -117,6 +117,7 @@ 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 d5904f8..90e3f39 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_HOST) += $(KVM)/arm/vgic.o kvm-$(CONFIG_KVM_ARM_HOST) += $(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..b1f8731 --- /dev/null +++ b/arch/arm64/kvm/debug.c @@ -0,0 +1,83 @@ +/* + * 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> + +static DEFINE_PER_CPU(u32, mdcr_el2); + +/** + * 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_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) + * - Power down debug registers (MDCR_EL2_TDOSA) + * + * 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); + + vcpu->arch.mdcr_el2 = __this_cpu_read(mdcr_el2) & MDCR_EL2_HPMN_MASK; + vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM | + MDCR_EL2_TPMCR | + MDCR_EL2_TDRA | + MDCR_EL2_TDOSA); + + /* Trap on access to debug registers? */ + if (trap_debug) + vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA; + else + vcpu->arch.mdcr_el2 &= ~MDCR_EL2_TDA; + +} + +void kvm_arm_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..15159aa 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 @@ -1295,4 +1286,10 @@ ENTRY(__kvm_hyp_vector) ventry el1_error_invalid // Error 32-bit EL1 ENDPROC(__kvm_hyp_vector) + +ENTRY(__kvm_get_mdcr_el2) + mrs x0, mdcr_el2 + ret +ENDPROC(__kvm_get_mdcr_el2) + .popsection
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> --- v3 - rename fns from arch->arm - preserve MDCR_EL2.HPMN setting - re-word some of the comments - fix some minor grammar nits - merge setting of mdcr_el2 - introduce trap_debug flag - move setup/clear within the irq lock section create mode 100644 arch/arm64/kvm/debug.c