This patch emulates debug registers and debug exception
to support guest using debug resource. This enables running
gdb/kgdb etc in guest.
On BOOKE architecture we cannot share debug resources between QEMU and
guest because:
When QEMU is using debug resources then debug exception must
be always enabled. To achieve this we set MSR_DE and also set
MSRP_DEP so guest cannot change MSR_DE.
When emulating debug resource for guest we want guest
to control MSR_DE (enable/disable debug interrupt on need).
So above mentioned two configuration cannot be supported
at the same time. So the result is that we cannot share
debug resources between QEMU and Guest on BOOKE architecture.
In the current design QEMU gets priority over guest, this means that if
QEMU is using debug resources then guest cannot use them and if guest is
using debug resource then QEMU can overwrite them.
Signed-off-by: Bharat Bhushan <Bharat.Bhushan@xxxxxxxxxxxxx>
---
v1->v2
- Clear DBCR0_EDM when userspace release debug resource
- change order of debug register and update in h/w register
- no debug interrupt on MRR/IDE debug event
arch/powerpc/include/asm/kvm_ppc.h | 3 +
arch/powerpc/include/asm/reg_booke.h | 2 +
arch/powerpc/kvm/booke.c | 35 +++++++-
arch/powerpc/kvm/booke_emulate.c | 157 +++++++++++++++++++++++++++++++++++
4 files changed, 196 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index fb86a22..05e58b6 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -206,6 +206,9 @@ extern int kvmppc_xics_get_xive(struct kvm *kvm, u32 irq, u32 *server,
extern int kvmppc_xics_int_on(struct kvm *kvm, u32 irq);
extern int kvmppc_xics_int_off(struct kvm *kvm, u32 irq);
+void kvmppc_core_dequeue_debug(struct kvm_vcpu *vcpu);
+void kvmppc_core_queue_debug(struct kvm_vcpu *vcpu);
+
union kvmppc_one_reg {
u32 wval;
u64 dval;
diff --git a/arch/powerpc/include/asm/reg_booke.h b/arch/powerpc/include/asm/reg_booke.h
index 464f108..150d485 100644
--- a/arch/powerpc/include/asm/reg_booke.h
+++ b/arch/powerpc/include/asm/reg_booke.h
@@ -307,6 +307,8 @@
* DBSR bits which have conflicting definitions on true Book E versus IBM 40x.
*/
#ifdef CONFIG_BOOKE
+#define DBSR_IDE 0x80000000 /* Imprecise Debug Event */
+#define DBSR_MRR 0x30000000 /* Most Recent Reset */
#define DBSR_IC 0x08000000 /* Instruction Completion */
#define DBSR_BT 0x04000000 /* Branch Taken */
#define DBSR_IRPT 0x02000000 /* Exception Debug Event */
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 5c2e26a..bd7d93f 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -267,6 +267,16 @@ static void kvmppc_core_dequeue_watchdog(struct kvm_vcpu *vcpu)
clear_bit(BOOKE_IRQPRIO_WATCHDOG, &vcpu->arch.pending_exceptions);
}
+void kvmppc_core_queue_debug(struct kvm_vcpu *vcpu)
+{
+ kvmppc_booke_queue_irqprio(vcpu, BOOKE_IRQPRIO_DEBUG);
+}
+
+void kvmppc_core_dequeue_debug(struct kvm_vcpu *vcpu)
+{
+ clear_bit(BOOKE_IRQPRIO_DEBUG, &vcpu->arch.pending_exceptions);
+}
+
static void set_guest_srr(struct kvm_vcpu *vcpu, unsigned long srr0, u32 srr1)
{
kvmppc_set_srr0(vcpu, srr0);
@@ -735,7 +745,27 @@ 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;
- /* Clear guest dbsr (vcpu->arch.dbsr).
+ if (vcpu->guest_debug == 0) {
+ /*
+ * Debug resources belong to Guest.
+ * Imprecise debug event are not injected
+ */
+ if (dbsr & DBSR_IDE)
+ return RESUME_GUEST;
+
+ if (dbsr && (vcpu->arch.shared->msr & MSR_DE) &&
+ (vcpu->arch.dbg_reg.dbcr0 & DBCR0_IDM))
+ kvmppc_core_queue_debug(vcpu);
+
+ /* Inject a program interrupt if trap debug is not allowed */
+ if ((dbsr & DBSR_TIE) && !(vcpu->arch.shared->msr & MSR_DE))
+ kvmppc_core_queue_program(vcpu, ESR_PTR);
+
+ return RESUME_GUEST;
+ }
+
+ /* Debug resource owned by userspace.
+ * Clear guest dbsr (vcpu->arch.dbsr).
* dbsr is not visible to userspace and we do not think any
* need to expose this to userspace because:
* Userspace cannot inject debug interrupt to guest (as this does
@@ -828,6 +858,8 @@ static void kvmppc_restart_interrupt(struct kvm_vcpu *vcpu,
case BOOKE_INTERRUPT_DEBUG:
/* Save DBSR before preemption is enabled */
vcpu->arch.dbsr = mfspr(SPRN_DBSR);
+ /* MASK out DBSR_MRR */
+ vcpu->arch.dbsr &= ~DBSR_MRR;
kvmppc_clear_dbsr();
break;
}
@@ -1858,6 +1890,7 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
if (!(dbg->control & KVM_GUESTDBG_ENABLE)) {
vcpu->arch.shadow_dbg_reg.dbcr0 = 0;
+ vcpu->arch.dbg_reg.dbcr0 = 0;
vcpu->guest_debug = 0;
kvm_guest_protect_msr(vcpu, MSR_DE, false);
return 0;
diff --git a/arch/powerpc/kvm/booke_emulate.c b/arch/powerpc/kvm/booke_emulate.c
index 4b9a079..c605897 100644
--- a/arch/powerpc/kvm/booke_emulate.c
+++ b/arch/powerpc/kvm/booke_emulate.c
@@ -131,6 +131,7 @@ int kvmppc_booke_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,
int kvmppc_booke_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, ulong spr_val)
{
int emulated = EMULATE_DONE;
+ bool debug_inst = false;
switch (sprn) {
case SPRN_DEAR:
@@ -145,14 +146,137 @@ int kvmppc_booke_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, ulong spr_val)
case SPRN_CSRR1:
vcpu->arch.csrr1 = spr_val;
break;
+ case SPRN_DSRR0:
+ vcpu->arch.dsrr0 = spr_val;
+ break;
+ case SPRN_DSRR1:
+ vcpu->arch.dsrr1 = spr_val;
+ break;
+ case SPRN_IAC1:
+ /*
+ * If userspace is debugging guest then guest
+ * can not access debug registers.
+ */
+ if (vcpu->guest_debug)
+ break;
+
+ debug_inst = true;
+ vcpu->arch.dbg_reg.iac1 = spr_val;
+ vcpu->arch.shadow_dbg_reg.iac1 = spr_val;
+ break;
+ case SPRN_IAC2:
+ /*
+ * If userspace is debugging guest then guest
+ * can not access debug registers.
+ */
+ if (vcpu->guest_debug)
+ break;
+
+ debug_inst = true;
+ vcpu->arch.dbg_reg.iac2 = spr_val;
+ vcpu->arch.shadow_dbg_reg.iac2 = spr_val;
+ break;
+#if CONFIG_PPC_ADV_DEBUG_IACS > 2
+ case SPRN_IAC3:
+ /*
+ * If userspace is debugging guest then guest
+ * can not access debug registers.
+ */
+ if (vcpu->guest_debug)
+ break;
+
+ debug_inst = true;
+ vcpu->arch.dbg_reg.iac3 = spr_val;
+ vcpu->arch.shadow_dbg_reg.iac3 = spr_val;
+ break;
+ case SPRN_IAC4:
+ /*
+ * If userspace is debugging guest then guest
+ * can not access debug registers.
+ */
+ if (vcpu->guest_debug)
+ break;
+
+ debug_inst = true;
+ vcpu->arch.dbg_reg.iac4 = spr_val;
+ vcpu->arch.shadow_dbg_reg.iac4 = spr_val;
+ break;
+#endif
+ case SPRN_DAC1:
+ /*
+ * If userspace is debugging guest then guest
+ * can not access debug registers.
+ */
+ if (vcpu->guest_debug)
+ break;
+
+ debug_inst = true;
+ vcpu->arch.dbg_reg.dac1 = spr_val;
+ vcpu->arch.shadow_dbg_reg.dac1 = spr_val;
+ break;
+ case SPRN_DAC2:
+ /*
+ * If userspace is debugging guest then guest
+ * can not access debug registers.
+ */
+ if (vcpu->guest_debug)
+ break;
+
+ debug_inst = true;
+ vcpu->arch.dbg_reg.dac2 = spr_val;
+ vcpu->arch.shadow_dbg_reg.dac2 = spr_val;
+ break;
case SPRN_DBCR0:
+ /*
+ * If userspace is debugging guest then guest
+ * can not access debug registers.
+ */
+ if (vcpu->guest_debug)
+ break;
+
+ debug_inst = true;
+ spr_val &= (DBCR0_IDM | DBCR0_IC | DBCR0_BT | DBCR0_TIE |
+ DBCR0_IAC1 | DBCR0_IAC2 | DBCR0_IAC3 | DBCR0_IAC4 |
+ DBCR0_DAC1R | DBCR0_DAC1W | DBCR0_DAC2R | DBCR0_DAC2W);
+
vcpu->arch.dbg_reg.dbcr0 = spr_val;
+ vcpu->arch.shadow_dbg_reg.dbcr0 = spr_val;
break;
case SPRN_DBCR1:
+ /*
+ * If userspace is debugging guest then guest
+ * can not access debug registers.
+ */
+ if (vcpu->guest_debug)
+ break;
+
+ debug_inst = true;
vcpu->arch.dbg_reg.dbcr1 = spr_val;
+ vcpu->arch.shadow_dbg_reg.dbcr1 = spr_val;
+ break;
+ case SPRN_DBCR2:
+ /*
+ * If userspace is debugging guest then guest
+ * can not access debug registers.
+ */
+ if (vcpu->guest_debug)
+ break;
+
+ debug_inst = true;
+ vcpu->arch.dbg_reg.dbcr2 = spr_val;
+ vcpu->arch.shadow_dbg_reg.dbcr2 = spr_val;
break;
case SPRN_DBSR:
+ /*
+ * If userspace is debugging guest then guest
+ * can not access debug registers.
+ */
+ if (vcpu->guest_debug)
+ break;
+
vcpu->arch.dbsr &= ~spr_val;
+ if (!(vcpu->arch.dbsr & ~DBSR_IDE))
+ kvmppc_core_dequeue_debug(vcpu);
break;
case SPRN_TSR:
kvmppc_clr_tsr_bits(vcpu, spr_val);
@@ -265,6 +389,10 @@ int kvmppc_booke_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, ulong spr_val)
emulated = EMULATE_FAIL;
}
+ if (debug_inst) {
+ current->thread.debug = vcpu->arch.shadow_dbg_reg;
+ switch_booke_debug_regs(&vcpu->arch.shadow_dbg_reg);
+ }
return emulated;
}
@@ -291,12 +419,41 @@ int kvmppc_booke_emulate_mfspr(struct kvm_vcpu *vcpu, int sprn, ulong *spr_val)
case SPRN_CSRR1:
*spr_val = vcpu->arch.csrr1;
break;
+ case SPRN_DSRR0:
+ *spr_val = vcpu->arch.dsrr0;
+ break;
+ case SPRN_DSRR1:
+ *spr_val = vcpu->arch.dsrr1;
+ break;
+ case SPRN_IAC1:
+ *spr_val = vcpu->arch.dbg_reg.iac1;
+ break;
+ case SPRN_IAC2:
+ *spr_val = vcpu->arch.dbg_reg.iac2;
+ break;
+#if CONFIG_PPC_ADV_DEBUG_IACS > 2
+ case SPRN_IAC3:
+ *spr_val = vcpu->arch.dbg_reg.iac3;
+ break;
+ case SPRN_IAC4:
+ *spr_val = vcpu->arch.dbg_reg.iac4;
+ break;
+#endif
+ case SPRN_DAC1:
+ *spr_val = vcpu->arch.dbg_reg.dac1;
+ break;
+ case SPRN_DAC2:
+ *spr_val = vcpu->arch.dbg_reg.dac2;
+ break;
case SPRN_DBCR0:
*spr_val = vcpu->arch.dbg_reg.dbcr0;
break;
case SPRN_DBCR1:
*spr_val = vcpu->arch.dbg_reg.dbcr1;
break;
+ case SPRN_DBCR2:
+ *spr_val = vcpu->arch.dbg_reg.dbcr2;
+ break;
case SPRN_DBSR:
*spr_val = vcpu->arch.dbsr;
break;
--
1.9.3
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