From 6a0ab738ef42d87951b3980f61b1f4cbb14d4171 Mon Sep 17 00:00:00 2001 From: Hollis Blanchard Date: Fri, 25 Jul 2008 13:54:49 -0500 Subject: KVM: ppc: guest breakpoint support Allow host userspace to program hardware debug registers to set breakpoints inside guests. Signed-off-by: Jerone Young Signed-off-by: Hollis Blanchard Signed-off-by: Avi Kivity --- arch/powerpc/kvm/powerpc.c | 84 +++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 83 insertions(+), 1 deletion(-) (limited to 'arch/powerpc/kvm/powerpc.c') diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 53826a5f6c0..b75607180dd 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -239,18 +239,100 @@ void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) { } +/* Note: clearing MSR[DE] just means that the debug interrupt will not be + * delivered *immediately*. Instead, it simply sets the appropriate DBSR bits. + * If those DBSR bits are still set when MSR[DE] is re-enabled, the interrupt + * will be delivered as an "imprecise debug event" (which is indicated by + * DBSR[IDE]. + */ +static void kvmppc_disable_debug_interrupts(void) +{ + mtmsr(mfmsr() & ~MSR_DE); +} + +static void kvmppc_restore_host_debug_state(struct kvm_vcpu *vcpu) +{ + kvmppc_disable_debug_interrupts(); + + mtspr(SPRN_IAC1, vcpu->arch.host_iac[0]); + mtspr(SPRN_IAC2, vcpu->arch.host_iac[1]); + mtspr(SPRN_IAC3, vcpu->arch.host_iac[2]); + mtspr(SPRN_IAC4, vcpu->arch.host_iac[3]); + mtspr(SPRN_DBCR1, vcpu->arch.host_dbcr1); + mtspr(SPRN_DBCR2, vcpu->arch.host_dbcr2); + mtspr(SPRN_DBCR0, vcpu->arch.host_dbcr0); + mtmsr(vcpu->arch.host_msr); +} + +static void kvmppc_load_guest_debug_registers(struct kvm_vcpu *vcpu) +{ + struct kvm_guest_debug *dbg = &vcpu->guest_debug; + u32 dbcr0 = 0; + + vcpu->arch.host_msr = mfmsr(); + kvmppc_disable_debug_interrupts(); + + /* Save host debug register state. */ + vcpu->arch.host_iac[0] = mfspr(SPRN_IAC1); + vcpu->arch.host_iac[1] = mfspr(SPRN_IAC2); + vcpu->arch.host_iac[2] = mfspr(SPRN_IAC3); + vcpu->arch.host_iac[3] = mfspr(SPRN_IAC4); + vcpu->arch.host_dbcr0 = mfspr(SPRN_DBCR0); + vcpu->arch.host_dbcr1 = mfspr(SPRN_DBCR1); + vcpu->arch.host_dbcr2 = mfspr(SPRN_DBCR2); + + /* set registers up for guest */ + + if (dbg->bp[0]) { + mtspr(SPRN_IAC1, dbg->bp[0]); + dbcr0 |= DBCR0_IAC1 | DBCR0_IDM; + } + if (dbg->bp[1]) { + mtspr(SPRN_IAC2, dbg->bp[1]); + dbcr0 |= DBCR0_IAC2 | DBCR0_IDM; + } + if (dbg->bp[2]) { + mtspr(SPRN_IAC3, dbg->bp[2]); + dbcr0 |= DBCR0_IAC3 | DBCR0_IDM; + } + if (dbg->bp[3]) { + mtspr(SPRN_IAC4, dbg->bp[3]); + dbcr0 |= DBCR0_IAC4 | DBCR0_IDM; + } + + mtspr(SPRN_DBCR0, dbcr0); + mtspr(SPRN_DBCR1, 0); + mtspr(SPRN_DBCR2, 0); +} + void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) { + if (vcpu->guest_debug.enabled) + kvmppc_load_guest_debug_registers(vcpu); } void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) { + if (vcpu->guest_debug.enabled) + kvmppc_restore_host_debug_state(vcpu); } int kvm_arch_vcpu_ioctl_debug_guest(struct kvm_vcpu *vcpu, struct kvm_debug_guest *dbg) { - return -ENOTSUPP; + int i; + + vcpu->guest_debug.enabled = dbg->enabled; + if (vcpu->guest_debug.enabled) { + for (i=0; i < ARRAY_SIZE(vcpu->guest_debug.bp); i++) { + if (dbg->breakpoints[i].enabled) + vcpu->guest_debug.bp[i] = dbg->breakpoints[i].address; + else + vcpu->guest_debug.bp[i] = 0; + } + } + + return 0; } static void kvmppc_complete_dcr_load(struct kvm_vcpu *vcpu, -- cgit v1.2.3 From 83aae4a8098eb8a40a2e9dab3714354182143b4f Mon Sep 17 00:00:00 2001 From: Hollis Blanchard Date: Fri, 25 Jul 2008 13:54:52 -0500 Subject: KVM: ppc: Write only modified shadow entries into the TLB on exit Track which TLB entries need to be written, instead of overwriting everything below the high water mark. Typically only a single guest TLB entry will be modified in a single exit. Guest boot time performance improvement: about 15%. Signed-off-by: Hollis Blanchard Signed-off-by: Avi Kivity --- arch/powerpc/kvm/powerpc.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'arch/powerpc/kvm/powerpc.c') diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index b75607180dd..90a6fc422b2 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -27,6 +27,7 @@ #include #include #include +#include gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn) @@ -307,14 +308,28 @@ static void kvmppc_load_guest_debug_registers(struct kvm_vcpu *vcpu) void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) { + int i; + if (vcpu->guest_debug.enabled) kvmppc_load_guest_debug_registers(vcpu); + + /* Mark every guest entry in the shadow TLB entry modified, so that they + * will all be reloaded on the next vcpu run (instead of being + * demand-faulted). */ + for (i = 0; i <= tlb_44x_hwater; i++) + kvmppc_tlbe_set_modified(vcpu, i); } void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) { if (vcpu->guest_debug.enabled) kvmppc_restore_host_debug_state(vcpu); + + /* Don't leave guest TLB entries resident when being de-scheduled. */ + /* XXX It would be nice to differentiate between heavyweight exit and + * sched_out here, since we could avoid the TLB flush for heavyweight + * exits. */ + _tlbia(); } int kvm_arch_vcpu_ioctl_debug_guest(struct kvm_vcpu *vcpu, -- cgit v1.2.3