On 14.03.2013, at 06:18, Bhushan Bharat-R65777 wrote: > > >> -----Original Message----- >> From: Alexander Graf [mailto:agraf@xxxxxxx] >> Sent: Thursday, March 07, 2013 7:09 PM >> To: Bhushan Bharat-R65777 >> Cc: kvm-ppc@xxxxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; Wood Scott-B07421; Bhushan >> Bharat-R65777 >> Subject: Re: [PATCH 7/7] KVM: PPC: Add userspace debug stub support >> >> >> On 28.02.2013, at 05:13, 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. >>> >>> Signed-off-by: Bharat Bhushan <bharat.bhushan@xxxxxxxxxxxxx> >>> --- >>> arch/powerpc/include/uapi/asm/kvm.h | 22 +++++- >>> arch/powerpc/kvm/booke.c | 143 +++++++++++++++++++++++++++++++--- >>> arch/powerpc/kvm/e500_emulate.c | 6 ++ >>> arch/powerpc/kvm/e500mc.c | 3 +- >>> 4 files changed, 155 insertions(+), 19 deletions(-) >>> >>> diff --git a/arch/powerpc/include/uapi/asm/kvm.h >>> b/arch/powerpc/include/uapi/asm/kvm.h >>> index 15f9a00..d7ce449 100644 >>> --- a/arch/powerpc/include/uapi/asm/kvm.h >>> +++ b/arch/powerpc/include/uapi/asm/kvm.h >>> @@ -25,6 +25,7 @@ >>> /* Select powerpc specific features in <linux/kvm.h> */ #define >>> __KVM_HAVE_SPAPR_TCE #define __KVM_HAVE_PPC_SMT >>> +#define __KVM_HAVE_GUEST_DEBUG >>> >>> struct kvm_regs { >>> __u64 pc; >>> @@ -267,7 +268,24 @@ struct kvm_fpu { >>> __u64 fpr[32]; >>> }; >>> >>> +/* >>> + * Defines for h/w breakpoint, watchpoint (read, write or both) and >>> + * software breakpoint. >>> + * These are used as "type" in KVM_SET_GUEST_DEBUG ioctl and "status" >>> + * for KVM_DEBUG_EXIT. >>> + */ >>> +#define KVMPPC_DEBUG_NONE 0x0 >>> +#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1) >>> +#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2) >>> +#define KVMPPC_DEBUG_WATCH_READ (1UL << 3) >>> struct kvm_debug_exit_arch { >>> + __u64 address; >>> + /* >>> + * exiting to userspace because of h/w breakpoint, watchpoint >>> + * (read, write or both) and software breakpoint. >>> + */ >>> + __u32 status; >>> + __u32 reserved; >>> }; >>> >>> /* for KVM_SET_GUEST_DEBUG */ >>> @@ -279,10 +297,6 @@ struct kvm_guest_debug_arch { >>> * Type denotes h/w breakpoint, read watchpoint, write >>> * watchpoint or watchpoint (both read and write). >>> */ >>> -#define KVMPPC_DEBUG_NOTYPE 0x0 >>> -#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1) >>> -#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2) >>> -#define KVMPPC_DEBUG_WATCH_READ (1UL << 3) >>> __u32 type; >>> __u32 reserved; >>> } bp[16]; >>> diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c index >>> 1de93a8..21b0313 100644 >>> --- a/arch/powerpc/kvm/booke.c >>> +++ b/arch/powerpc/kvm/booke.c >>> @@ -133,6 +133,30 @@ 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. Do not allow guest to change MSR[DE]. >>> + */ >>> + vcpu->arch.shared->msr |= MSR_DE; >>> + mtspr(SPRN_MSRP, mfspr(SPRN_MSRP) | MSRP_DEP); #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 +174,7 @@ 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, @@ >>> -736,6 +761,13 @@ static int emulation_exit(struct kvm_run *run, struct >> kvm_vcpu *vcpu) >>> run->exit_reason = KVM_EXIT_DCR; >>> return RESUME_HOST; >>> >>> + case EMULATE_EXIT_USER: >>> + run->exit_reason = KVM_EXIT_DEBUG; >>> + run->debug.arch.address = vcpu->arch.pc; >>> + run->debug.arch.status = 0; >>> + kvmppc_account_exit(vcpu, DEBUG_EXITS); >> >> As mentioned previously, this is wrong and needs to go into the instruction >> emulation code for that opcode. > > ok > >> >>> + return RESUME_HOST; >>> + >>> case EMULATE_FAIL: >>> printk(KERN_CRIT "%s: emulation at %lx failed (%08x)\n", >>> __func__, vcpu->arch.pc, vcpu->arch.last_inst); @@ -751,6 >>> +783,28 @@ 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) { >>> + u32 dbsr = vcpu->arch.dbsr; >>> + run->debug.arch.status = 0; >>> + run->debug.arch.address = vcpu->arch.pc; >> >> This should go into the if(breakpoint) branch. > > Can there be the case when do breakpoint and debug interrupt happen? At least not according to the code below :). If that's a valid case, then quite a bit of code would need to be remodeled. I'd say ignore the possibility for now. > >> >>> + >>> + 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 = vcpu->arch.shadow_dbg_reg.dac[0]; >>> + else if (dbsr & (DBSR_DAC2R | DBSR_DAC2W)) >>> + run->debug.arch.address = vcpu->arch.shadow_dbg_reg.dac[1]; >>> + } >>> + >>> + return RESUME_HOST; >>> +} >>> + >>> static void kvmppc_fill_pt_regs(struct pt_regs *regs) { >>> ulong r1, ip, msr, lr; >>> @@ -1110,18 +1164,11 @@ 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; >>> } >>> >>> @@ -1172,7 +1219,7 @@ 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 >>> @@ -1527,10 +1574,80 @@ int kvm_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu, >> struct kvm_one_reg *reg) >>> return r; >>> } >>> >>> +#define BP_NUM KVMPPC_BOOKE_IAC_NUM >>> +#define WP_NUM KVMPPC_BOOKE_DAC_NUM >>> + >>> int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu, >>> struct kvm_guest_debug *dbg) >>> { >>> - return -EINVAL; >>> + >>> + if (!(dbg->control & KVM_GUESTDBG_ENABLE)) { >>> + /* Clear All debug events */ >>> + vcpu->arch.shadow_dbg_reg.dbcr0 = 0; >>> + vcpu->guest_debug = 0; >>> + return 0; >>> + } >>> + >>> + vcpu->guest_debug = dbg->control; >>> + vcpu->arch.shadow_dbg_reg.dbcr0 = 0; >>> + /* Set DBCR0_EDM in guest visible DBCR0 register. */ >>> + vcpu->arch.dbg_reg.dbcr0 = DBCR0_EDM; >>> + >>> + if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) >>> + vcpu->arch.shadow_dbg_reg.dbcr0 |= DBCR0_IDM | DBCR0_IC; >>> + >>> + if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) { >> >> if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)) { >> /* Code below handles only HW breakpoints */ >> return 0; >> } > > ok > >> >>> + struct kvmppc_booke_debug_reg *gdbgr = >>> + &(vcpu->arch.shadow_dbg_reg); >>> + int n, b = 0, w = 0; >>> + const u32 bp_code[] = { >>> + DBCR0_IAC1 | DBCR0_IDM, >>> + DBCR0_IAC2 | DBCR0_IDM, >>> + DBCR0_IAC3 | DBCR0_IDM, >>> + DBCR0_IAC4 | DBCR0_IDM >>> + }; >>> + const u32 wp_code[] = { >>> + DBCR0_DAC1W | DBCR0_IDM, >>> + DBCR0_DAC2W | DBCR0_IDM, >>> + DBCR0_DAC1R | DBCR0_IDM, >>> + DBCR0_DAC2R | DBCR0_IDM >>> + }; >>> + >>> +#ifndef CONFIG_KVM_BOOKE_HV >> >> Please no double negation. > You mean we should use > #ifdef CONFIG_KVM_BOOKE_HV > gdbgr->dbcr1 = 0; > gdbgr->dbcr2 = 0; > #else > gdbgr->dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US | > DBCR1_IAC3US | DBCR1_IAC4US; > gdbgr->dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US; > #endif > >> Also, what is this about? > > This These bits says that IAC1-4 and DAC1-2 can happen when MSR.PR is set of not. > On BOOKE (e500v2); MSR.PR = 1 when guest is running. So we need to set these bits > On BOOKE-HV (e500mc+); MSR.PR = 0 when guest is running. So we do not need these bits to be set. Ah, please add a comment explaining this here. > >> >>> + gdbgr->dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US | >>> + DBCR1_IAC3US | DBCR1_IAC4US; >>> + gdbgr->dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US; #else >>> + gdbgr->dbcr1 = 0; >>> + gdbgr->dbcr2 = 0; >>> +#endif >>> + >>> + for (n = 0; n < (BP_NUM + WP_NUM); n++) { >>> + u32 type = dbg->arch.bp[n].type; >>> + >>> + if (!type) >>> + break; >>> + >>> + if (type & (KVMPPC_DEBUG_WATCH_READ | >>> + KVMPPC_DEBUG_WATCH_WRITE)) { >>> + if (w < WP_NUM) { >>> + if (type & KVMPPC_DEBUG_WATCH_READ) >>> + gdbgr->dbcr0 |= wp_code[w + 2]; >>> + if (type & KVMPPC_DEBUG_WATCH_WRITE) >>> + gdbgr->dbcr0 |= wp_code[w]; >>> + gdbgr->dac[w] = dbg->arch.bp[n].addr; >>> + w++; >>> + } >>> + } else if (type & KVMPPC_DEBUG_BREAKPOINT) { >>> + if (b < BP_NUM) { >>> + gdbgr->dbcr0 |= bp_code[b]; >>> + gdbgr->iac[b] = dbg->arch.bp[n].addr; >>> + b++; >>> + } >>> + } >>> + } >>> + } >>> + return 0; >>> } >>> >>> int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu >>> *fpu) diff --git a/arch/powerpc/kvm/e500_emulate.c >>> b/arch/powerpc/kvm/e500_emulate.c index e78f353..83ac877 100644 >>> --- a/arch/powerpc/kvm/e500_emulate.c >>> +++ b/arch/powerpc/kvm/e500_emulate.c >>> @@ -26,6 +26,7 @@ >>> #define XOP_TLBRE 946 >>> #define XOP_TLBWE 978 >>> #define XOP_TLBILX 18 >>> +#define XOP_EHPRIV 270 >>> >>> #ifdef CONFIG_KVM_E500MC >>> static int dbell2prio(ulong param) >>> @@ -130,6 +131,11 @@ int kvmppc_core_emulate_op(struct kvm_run *run, struct >> kvm_vcpu *vcpu, >>> emulated = kvmppc_e500_emul_tlbivax(vcpu, ea); >>> break; >>> >>> + case XOP_EHPRIV: >>> + emulated = EMULATE_EXIT_USER; >>> + *advance = 0; >>> + break; >>> + >>> default: >>> emulated = EMULATE_FAIL; >>> } >>> diff --git a/arch/powerpc/kvm/e500mc.c b/arch/powerpc/kvm/e500mc.c >>> index 1f89d26..f5fc6f5 100644 >>> --- a/arch/powerpc/kvm/e500mc.c >>> +++ b/arch/powerpc/kvm/e500mc.c >>> @@ -182,8 +182,7 @@ int kvmppc_core_vcpu_setup(struct kvm_vcpu *vcpu) >>> { >>> struct kvmppc_vcpu_e500 *vcpu_e500 = to_e500(vcpu); >>> >>> - vcpu->arch.shadow_epcr = SPRN_EPCR_DSIGS | SPRN_EPCR_DGTMI | \ >>> - SPRN_EPCR_DUVD; >>> + vcpu->arch.shadow_epcr = SPRN_EPCR_DSIGS | SPRN_EPCR_DGTMI; >> >> Doesn't this route all debug events through the host? > > No; This means that debug events can occur in hypervisor state or not. > > EPCR.DUVD = 0 ; Debug events can occur in the hypervisor state. > > EPCR.DUVD = 1 ; Debug events cannot occur in the hypervisor state. > > So we allow debug events to occur in hypervisor state. Why do we care about debug events in our entry/exit code and didn't care about them before? If anything, this is a completely separate patch, orthogonal to this patch series, and requires a good bit of explanation. Alex > On lightweight exit we set ECPU.DUVD (if guest using debug facility) so debug events will not come during guest entry/exit code. On guest exit we clear this bit (after restoring host state) so hypervisor can use debug features. > > Thanks > -Bharat >> >> >> Alex >> >>> #ifdef CONFIG_64BIT >>> vcpu->arch.shadow_epcr |= SPRN_EPCR_ICM; #endif >>> -- >>> 1.7.0.4 >>> >>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in >>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
