> -----Original Message----- > From: Alexander Graf [mailto:ag...@suse.de] > Sent: Monday, June 24, 2013 4:13 PM > To: Bhushan Bharat-R65777 > Cc: kvm-ppc@vger.kernel.org; k...@vger.kernel.org; Wood Scott-B07421; > tiejun.c...@windriver.com; Bhushan Bharat-R65777 > Subject: Re: [PATCH 6/6 v5] KVM: PPC: Add userspace debug stub support > > > On 24.06.2013, at 11:08, Bharat Bhushan wrote: > > > This patch adds the debug stub support on booke/bookehv. > > Now QEMU debug stub can use hw breakpoint, watchpoint and software > > breakpoint to debug guest. > > > > This is how we save/restore debug register context when switching > > between guest, userspace and kernel user-process: > > > > When QEMU is running > > -> thread->debug_reg == QEMU debug register context. > > -> Kernel will handle switching the debug register on context switch. > > -> no vcpu_load() called > > > > QEMU makes ioctls (except RUN) > > -> This will call vcpu_load() > > -> should not change context. > > -> Some ioctls can change vcpu debug register, context saved in > > -> vcpu->debug_regs > > > > QEMU Makes RUN ioctl > > -> Save thread->debug_reg on STACK > > -> Store thread->debug_reg == vcpu->debug_reg load thread->debug_reg > > -> RUN VCPU ( So thread points to vcpu context ) > > > > Context switch happens When VCPU running > > -> makes vcpu_load() should not load any context kernel loads the vcpu > > -> context as thread->debug_regs points to vcpu context. > > > > On heavyweight_exit > > -> Load the context saved on stack in thread->debug_reg > > > > Currently we do not support debug resource emulation to guest, On > > debug exception, always exit to user space irrespective of user space > > is expecting the debug exception or not. If this is unexpected > > exception (breakpoint/watchpoint event not set by > > userspace) then let us leave the action on user space. This is similar > > to what it was before, only thing is that now we have proper exit > > state available to user space. > > > > Signed-off-by: Bharat Bhushan <bharat.bhus...@freescale.com> > > --- > > arch/powerpc/include/asm/kvm_host.h | 3 + > > arch/powerpc/include/uapi/asm/kvm.h | 1 + > > arch/powerpc/kvm/booke.c | 233 > > ++++++++++++++++++++++++++++++++--- > > arch/powerpc/kvm/booke.h | 5 + > > 4 files changed, 224 insertions(+), 18 deletions(-) > > > > diff --git a/arch/powerpc/include/asm/kvm_host.h > > b/arch/powerpc/include/asm/kvm_host.h > > index 838a577..aeb490d 100644 > > --- a/arch/powerpc/include/asm/kvm_host.h > > +++ b/arch/powerpc/include/asm/kvm_host.h > > @@ -524,7 +524,10 @@ struct kvm_vcpu_arch { > > u32 eptcfg; > > u32 epr; > > u32 crit_save; > > + /* guest debug registers*/ > > struct debug_reg dbg_reg; > > + /* hardware visible debug registers when in guest state */ > > + struct debug_reg shadow_dbg_reg; > > #endif > > gpa_t paddr_accessed; > > gva_t vaddr_accessed; > > diff --git a/arch/powerpc/include/uapi/asm/kvm.h > > b/arch/powerpc/include/uapi/asm/kvm.h > > index ded0607..f5077c2 100644 > > --- a/arch/powerpc/include/uapi/asm/kvm.h > > +++ b/arch/powerpc/include/uapi/asm/kvm.h > > @@ -27,6 +27,7 @@ > > #define __KVM_HAVE_PPC_SMT > > #define __KVM_HAVE_IRQCHIP > > #define __KVM_HAVE_IRQ_LINE > > +#define __KVM_HAVE_GUEST_DEBUG > > > > struct kvm_regs { > > __u64 pc; > > diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c index > > 3e9fc1d..8be3502 100644 > > --- a/arch/powerpc/kvm/booke.c > > +++ b/arch/powerpc/kvm/booke.c > > @@ -133,6 +133,29 @@ static void kvmppc_vcpu_sync_fpu(struct kvm_vcpu > > *vcpu) #endif } > > > > +static void kvmppc_vcpu_sync_debug(struct kvm_vcpu *vcpu) { > > + /* Synchronize guest's desire to get debug interrupts into shadow > > +MSR */ #ifndef CONFIG_KVM_BOOKE_HV > > + vcpu->arch.shadow_msr &= ~MSR_DE; > > + vcpu->arch.shadow_msr |= vcpu->arch.shared->msr & MSR_DE; #endif > > + > > + /* Force enable debug interrupts when user space wants to debug */ > > + if (vcpu->guest_debug) { > > +#ifdef CONFIG_KVM_BOOKE_HV > > + /* > > + * Since there is no shadow MSR, sync MSR_DE into the guest > > + * visible MSR. > > + */ > > + vcpu->arch.shared->msr |= MSR_DE; > > +#else > > + vcpu->arch.shadow_msr |= MSR_DE; > > + vcpu->arch.shared->msr &= ~MSR_DE; > > +#endif > > + } > > +} > > + > > /* > > * Helper function for "full" MSR writes. No need to call this if > > only > > * EE/CE/ME/DE/RI are changing. > > @@ -150,6 +173,7 @@ void kvmppc_set_msr(struct kvm_vcpu *vcpu, u32 new_msr) > > kvmppc_mmu_msr_notify(vcpu, old_msr); > > kvmppc_vcpu_sync_spe(vcpu); > > kvmppc_vcpu_sync_fpu(vcpu); > > + kvmppc_vcpu_sync_debug(vcpu); > > } > > > > static void kvmppc_booke_queue_irqprio(struct kvm_vcpu *vcpu, @@ > > -655,6 +679,7 @@ int kvmppc_core_check_requests(struct kvm_vcpu *vcpu) > > int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu) { > > int ret, s; > > + struct thread_struct thread; > > #ifdef CONFIG_PPC_FPU > > unsigned int fpscr; > > int fpexc_mode; > > @@ -698,12 +723,21 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, > > struct kvm_vcpu *vcpu) > > > > kvmppc_load_guest_fp(vcpu); > > #endif > > + /* Switch to guest debug context */ > > + thread.debug = vcpu->arch.shadow_dbg_reg; > > + switch_booke_debug_regs(&thread); > > + thread.debug = current->thread.debug; > > + current->thread.debug = vcpu->arch.shadow_dbg_reg; > > > > ret = __kvmppc_vcpu_run(kvm_run, vcpu); > > > > /* No need for kvm_guest_exit. It's done in handle_exit. > > We also get here with interrupts enabled. */ > > > > + /* Switch back to user space debug context */ > > + switch_booke_debug_regs(&thread); > > + current->thread.debug = thread.debug; > > + > > #ifdef CONFIG_PPC_FPU > > kvmppc_save_guest_fp(vcpu); > > > > @@ -759,6 +793,30 @@ static int emulation_exit(struct kvm_run *run, struct > kvm_vcpu *vcpu) > > } > > } > > > > +static int kvmppc_handle_debug(struct kvm_run *run, struct kvm_vcpu > > +*vcpu) { > > + struct debug_reg *dbg_reg = &(vcpu->arch.shadow_dbg_reg); > > + u32 dbsr = vcpu->arch.dbsr; > > + > > + run->debug.arch.status = 0; > > + run->debug.arch.address = vcpu->arch.pc; > > + > > + if (dbsr & (DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4)) { > > + run->debug.arch.status |= KVMPPC_DEBUG_BREAKPOINT; > > + } else { > > + if (dbsr & (DBSR_DAC1W | DBSR_DAC2W)) > > + run->debug.arch.status |= KVMPPC_DEBUG_WATCH_WRITE; > > + else if (dbsr & (DBSR_DAC1R | DBSR_DAC2R)) > > + run->debug.arch.status |= KVMPPC_DEBUG_WATCH_READ; > > + if (dbsr & (DBSR_DAC1R | DBSR_DAC1W)) > > + run->debug.arch.address = dbg_reg->dac1; > > + else if (dbsr & (DBSR_DAC2R | DBSR_DAC2W)) > > + run->debug.arch.address = dbg_reg->dac2; > > + } > > + > > + return RESUME_HOST; > > +} > > + > > static void kvmppc_fill_pt_regs(struct pt_regs *regs) { > > ulong r1, ip, msr, lr; > > @@ -819,6 +877,11 @@ static void kvmppc_restart_interrupt(struct kvm_vcpu > *vcpu, > > case BOOKE_INTERRUPT_CRITICAL: > > unknown_exception(®s); > > break; > > + case BOOKE_INTERRUPT_DEBUG: > > + /* Save DBSR before preemption is enabled */ > > + vcpu->arch.dbsr = mfspr(SPRN_DBSR); > > + kvmppc_clear_dbsr(); > > + break; > > } > > } > > > > @@ -1118,18 +1181,10 @@ int kvmppc_handle_exit(struct kvm_run *run, struct > kvm_vcpu *vcpu, > > } > > > > case BOOKE_INTERRUPT_DEBUG: { > > - u32 dbsr; > > - > > - vcpu->arch.pc = mfspr(SPRN_CSRR0); > > - > > - /* clear IAC events in DBSR register */ > > - dbsr = mfspr(SPRN_DBSR); > > - dbsr &= DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4; > > - mtspr(SPRN_DBSR, dbsr); > > - > > - run->exit_reason = KVM_EXIT_DEBUG; > > + r = kvmppc_handle_debug(run, vcpu); > > + if (r == RESUME_HOST) > > + run->exit_reason = KVM_EXIT_DEBUG; > > kvmppc_account_exit(vcpu, DEBUG_EXITS); > > - r = RESUME_HOST; > > break; > > } > > > > @@ -1180,7 +1235,7 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu) > > kvmppc_set_msr(vcpu, 0); > > > > #ifndef CONFIG_KVM_BOOKE_HV > > - vcpu->arch.shadow_msr = MSR_USER | MSR_DE | MSR_IS | MSR_DS; > > + vcpu->arch.shadow_msr = MSR_USER | MSR_IS | MSR_DS; > > vcpu->arch.shadow_pid = 1; > > vcpu->arch.shared->msr = 0; > > #endif > > @@ -1557,12 +1612,6 @@ int kvm_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu, > struct kvm_one_reg *reg) > > return r; > > } > > > > -int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu, > > - struct kvm_guest_debug *dbg) > > -{ > > - return -EINVAL; > > -} > > - > > int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu > > *fpu) { > > return -ENOTSUPP; > > @@ -1668,6 +1717,151 @@ void kvmppc_decrementer_func(unsigned long data) > > kvmppc_set_tsr_bits(vcpu, TSR_DIS); > > } > > > > +static int kvmppc_booke_add_breakpoint(struct debug_reg *dbg_reg, > > + uint64_t addr, int index) > > +{ > > + switch (index) { > > + case 0: > > + dbg_reg->dbcr0 |= DBCR0_IAC1; > > + dbg_reg->iac1 = addr; > > + break; > > + case 1: > > + dbg_reg->dbcr0 |= DBCR0_IAC2; > > + dbg_reg->iac2 = addr; > > + break; > > +#if CONFIG_PPC_ADV_DEBUG_IACS > 2 > > + case 2: > > + dbg_reg->dbcr0 |= DBCR0_IAC3; > > + dbg_reg->iac3 = addr; > > + break; > > + case 3: > > + dbg_reg->dbcr0 |= DBCR0_IAC4; > > + dbg_reg->iac4 = addr; > > + break; > > +#endif > > + default: > > + return -EINVAL; > > + } > > + > > + dbg_reg->dbcr0 |= DBCR0_IDM; > > + return 0; > > +} > > + > > +static int kvmppc_booke_add_watchpoint(struct debug_reg *dbg_reg, uint64_t > addr, > > + int type, int index) > > +{ > > + switch (index) { > > + case 0: > > + if (type & KVMPPC_DEBUG_WATCH_READ) > > + dbg_reg->dbcr0 |= DBCR0_DAC1R; > > + if (type & KVMPPC_DEBUG_WATCH_WRITE) > > + dbg_reg->dbcr0 |= DBCR0_DAC1W; > > + dbg_reg->dac1 = addr; > > + break; > > + case 1: > > + if (type & KVMPPC_DEBUG_WATCH_READ) > > + dbg_reg->dbcr0 |= DBCR0_DAC2R; > > + if (type & KVMPPC_DEBUG_WATCH_WRITE) > > + dbg_reg->dbcr0 |= DBCR0_DAC2W; > > + dbg_reg->dac2 = addr; > > + break; > > + default: > > + return -EINVAL; > > + } > > + > > + dbg_reg->dbcr0 |= DBCR0_IDM; > > + return 0; > > +} > > + > > +#ifdef CONFIG_KVM_BOOKE_HV > > +void kvm_guest_may_change_msr_de(struct kvm_vcpu *vcpu, bool > > +may_change) { > > + if (may_change) > > + /* Allow guest to change MSR.DE */ > > + vcpu->arch.shadow_msrp &= ~MSRP_DEP; > > + else > > + /* Don't allow guest to change MSR.DE */ > > + vcpu->arch.shadow_msrp |= MSRP_DEP; > > + > > +} > > +#endif > > Could you please provide this function regardless of CONFIG_KVM_BOOKE_HV? For > PR, just save a bool away somewhere and emulate the same behavior (guest may > not > modify MSR.DE).
You mean modify kvmppc_set_msr() (kvmppc_vcpu_sync_debug()) to consider this bool to change/not_change msr.de? Thanks -Bharat > > That way we ensure consistency between the targets and get rid of ugly > #ifdef's > :). > > > Alex > -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
