> -----Original Message----- > From: Alexander Graf [mailto:ag...@suse.de] > Sent: Friday, January 25, 2013 5:13 PM > To: Bhushan Bharat-R65777 > Cc: kvm-ppc@vger.kernel.org; k...@vger.kernel.org; Bhushan Bharat-R65777 > Subject: Re: [PATCH 3/8] KVM: PPC: booke: Added debug handler > > > On 16.01.2013, at 09:24, Bharat Bhushan wrote: > > > From: Bharat Bhushan <bharat.bhus...@freescale.com> > > > > Installed debug handler will be used for guest debug support and debug > > facility emulation features (patches for these features will follow > > this patch). > > > > Signed-off-by: Liu Yu <yu....@freescale.com> > > [bharat.bhus...@freescale.com: Substantial changes] > > Signed-off-by: Bharat Bhushan <bharat.bhus...@freescale.com> > > --- > > arch/powerpc/include/asm/kvm_host.h | 1 + > > arch/powerpc/kernel/asm-offsets.c | 1 + > > arch/powerpc/kvm/booke_interrupts.S | 49 > > ++++++++++++++++++++++++++++++----- > > 3 files changed, 44 insertions(+), 7 deletions(-) > > > > diff --git a/arch/powerpc/include/asm/kvm_host.h > > b/arch/powerpc/include/asm/kvm_host.h > > index 8a72d59..f4ba881 100644 > > --- a/arch/powerpc/include/asm/kvm_host.h > > +++ b/arch/powerpc/include/asm/kvm_host.h > > @@ -503,6 +503,7 @@ struct kvm_vcpu_arch { > > u32 tlbcfg[4]; > > u32 mmucfg; > > u32 epr; > > + u32 crit_save; > > struct kvmppc_booke_debug_reg dbg_reg; #endif > > gpa_t paddr_accessed; > > diff --git a/arch/powerpc/kernel/asm-offsets.c > > b/arch/powerpc/kernel/asm-offsets.c > > index 46f6afd..02048f3 100644 > > --- a/arch/powerpc/kernel/asm-offsets.c > > +++ b/arch/powerpc/kernel/asm-offsets.c > > @@ -562,6 +562,7 @@ int main(void) > > DEFINE(VCPU_LAST_INST, offsetof(struct kvm_vcpu, arch.last_inst)); > > DEFINE(VCPU_FAULT_DEAR, offsetof(struct kvm_vcpu, arch.fault_dear)); > > DEFINE(VCPU_FAULT_ESR, offsetof(struct kvm_vcpu, arch.fault_esr)); > > + DEFINE(VCPU_CRIT_SAVE, offsetof(struct kvm_vcpu, arch.crit_save)); > > #endif /* CONFIG_PPC_BOOK3S */ > > #endif /* CONFIG_KVM */ > > > > diff --git a/arch/powerpc/kvm/booke_interrupts.S > > b/arch/powerpc/kvm/booke_interrupts.S > > index eae8483..dd9c5d4 100644 > > --- a/arch/powerpc/kvm/booke_interrupts.S > > +++ b/arch/powerpc/kvm/booke_interrupts.S > > @@ -52,12 +52,7 @@ > > (1<<BOOKE_INTERRUPT_PROGRAM) | \ > > (1<<BOOKE_INTERRUPT_DTLB_MISS)) > > > > -.macro KVM_HANDLER ivor_nr scratch srr0 > > -_GLOBAL(kvmppc_handler_\ivor_nr) > > - /* Get pointer to vcpu and record exit number. */ > > - mtspr \scratch , r4 > > - mfspr r4, SPRN_SPRG_THREAD > > - lwz r4, THREAD_KVM_VCPU(r4) > > +.macro __KVM_HANDLER ivor_nr scratch srr0 > > stw r3, VCPU_GPR(R3)(r4) > > stw r5, VCPU_GPR(R5)(r4) > > stw r6, VCPU_GPR(R6)(r4) > > @@ -74,6 +69,46 @@ _GLOBAL(kvmppc_handler_\ivor_nr) > > bctr > > .endm > > > > +.macro KVM_HANDLER ivor_nr scratch srr0 > > +_GLOBAL(kvmppc_handler_\ivor_nr) > > + /* Get pointer to vcpu and record exit number. */ > > + mtspr \scratch , r4 > > + mfspr r4, SPRN_SPRG_THREAD > > + lwz r4, THREAD_KVM_VCPU(r4) > > + __KVM_HANDLER \ivor_nr \scratch \srr0 .endm > > + > > +.macro KVM_DBG_HANDLER ivor_nr scratch srr0 > > +_GLOBAL(kvmppc_handler_\ivor_nr) > > + mtspr \scratch, r4 > > + mfspr r4, SPRN_SPRG_THREAD > > + lwz r4, THREAD_KVM_VCPU(r4) > > + stw r3, VCPU_CRIT_SAVE(r4) > > + mfcr r3 > > + mfspr r4, SPRN_CSRR1 > > + andi. r4, r4, MSR_PR > > + bne 1f > > > > + /* debug interrupt happened in enter/exit path */ > > + mfspr r4, SPRN_CSRR1 > > + rlwinm r4, r4, 0, ~MSR_DE > > + mtspr SPRN_CSRR1, r4 > > + lis r4, 0xffff > > + ori r4, r4, 0xffff > > + mtspr SPRN_DBSR, r4 > > + mfspr r4, SPRN_SPRG_THREAD > > + lwz r4, THREAD_KVM_VCPU(r4) > > + mtcr r3 > > + lwz r3, VCPU_CRIT_SAVE(r4) > > + mfspr r4, \scratch > > + rfci > > What is this part doing? Try to ignore the debug exit?
As BOOKE doesn't have hardware support for virtualization, hardware never know current pc is in guest or in host. So when enable hardware single step for guest, it cannot be disabled at the time guest exit. Thus, we'll see that an single step interrupt happens at the beginning of guest exit path. With the above code we recognize this kind of single step interrupt disable single step and rfci. > Why would we have MSR_DE > enabled in the first place when we can't handle it? When QEMU is using hardware debug resource then we always set MSR_DE during guest is running. > > > +1: /* debug interrupt happened in guest */ > > + mtcr r3 > > + mfspr r4, SPRN_SPRG_THREAD > > + lwz r4, THREAD_KVM_VCPU(r4) > > + lwz r3, VCPU_CRIT_SAVE(r4) > > + __KVM_HANDLER \ivor_nr \scratch \srr0 > > I don't think you need the __KVM_HANDLER split. This should be quite easily > refactorable into a simple DBG prolog. Can you please elaborate how you are envisioning this? Thanks -Bharat > > > Alex > > > +.endm > > + > > .macro KVM_HANDLER_ADDR ivor_nr > > .long kvmppc_handler_\ivor_nr > > .endm > > @@ -98,7 +133,7 @@ KVM_HANDLER BOOKE_INTERRUPT_FIT SPRN_SPRG_RSCRATCH0 > > SPRN_SRR0 KVM_HANDLER BOOKE_INTERRUPT_WATCHDOG SPRN_SPRG_RSCRATCH_CRIT > > SPRN_CSRR0 KVM_HANDLER BOOKE_INTERRUPT_DTLB_MISS SPRN_SPRG_RSCRATCH0 > > SPRN_SRR0 KVM_HANDLER BOOKE_INTERRUPT_ITLB_MISS SPRN_SPRG_RSCRATCH0 > > SPRN_SRR0 -KVM_HANDLER BOOKE_INTERRUPT_DEBUG SPRN_SPRG_RSCRATCH_CRIT > > SPRN_CSRR0 > > +KVM_DBG_HANDLER BOOKE_INTERRUPT_DEBUG SPRN_SPRG_RSCRATCH_CRIT > > +SPRN_CSRR0 > > KVM_HANDLER BOOKE_INTERRUPT_SPE_UNAVAIL SPRN_SPRG_RSCRATCH0 SPRN_SRR0 > > KVM_HANDLER BOOKE_INTERRUPT_SPE_FP_DATA SPRN_SPRG_RSCRATCH0 SPRN_SRR0 > > KVM_HANDLER BOOKE_INTERRUPT_SPE_FP_ROUND SPRN_SPRG_RSCRATCH0 SPRN_SRR0 > > -- > > 1.7.0.4 > > > > > -- 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
