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* [PATCH 1/5] KVM: PPC: BOOKE: allow debug interrupt at "debug level"
@ 2014-08-04  7:55 ` Bharat Bhushan
  0 siblings, 0 replies; 16+ messages in thread
From: Bharat Bhushan @ 2014-08-04  7:52 UTC (permalink / raw)
  To: agraf, kvm-ppc; +Cc: kvm, scottwood, stuart.yoder, Bharat Bhushan

Debug interrupt can be either "critical level" or "debug level".
There are separate set of save/restore registers used for different level.
Example: DSRR0/DSRR1 are used for "debug level" and CSRR0/CSRR1
are used for critical level debug interrupt.

Using CPU_FTR_DEBUG_LVL_EXC to decide which interrupt level to be used.

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
---
 arch/powerpc/kvm/booke.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index b4c89fa..322da7d 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -377,7 +377,11 @@ static int kvmppc_booke_irqprio_deliver(struct kvm_vcpu *vcpu,
 		allowed = vcpu->arch.shared->msr & MSR_DE;
 		allowed = allowed && !crit;
 		msr_mask = MSR_ME;
-		int_class = INT_CLASS_CRIT;
+		if (cpu_has_feature(CPU_FTR_DEBUG_LVL_EXC))
+			int_class = INT_CLASS_DBG;
+		else
+			int_class = INT_CLASS_CRIT;
+
 		break;
 	}
 
-- 
1.9.3


^ permalink raw reply related	[flat|nested] 16+ messages in thread
* [PATCH 2/5] KVM: PPC: BOOKE : Emulate rfdi instruction
  2014-08-04  7:55 ` Bharat Bhushan
@ 2014-08-04  7:55   ` Bharat Bhushan
  -1 siblings, 0 replies; 16+ messages in thread
From: Bharat Bhushan @ 2014-08-04  7:52 UTC (permalink / raw)
  To: agraf, kvm-ppc; +Cc: kvm, scottwood, stuart.yoder, Bharat Bhushan

This patch adds "rfdi" instruction emulation which is required for
guest debug hander on BOOKE-HV

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
---
 arch/powerpc/include/asm/kvm_host.h |  1 +
 arch/powerpc/kvm/booke_emulate.c    | 13 +++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 98d9dd5..636b230 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -144,6 +144,7 @@ enum kvm_exit_types {
 	EMULATED_TLBWE_EXITS,
 	EMULATED_RFI_EXITS,
 	EMULATED_RFCI_EXITS,
+	EMULATED_RFDI_EXITS,
 	DEC_EXITS,
 	EXT_INTR_EXITS,
 	HALT_WAKEUP,
diff --git a/arch/powerpc/kvm/booke_emulate.c b/arch/powerpc/kvm/booke_emulate.c
index 28c1588..4b9a079 100644
--- a/arch/powerpc/kvm/booke_emulate.c
+++ b/arch/powerpc/kvm/booke_emulate.c
@@ -25,6 +25,7 @@
 
 #define OP_19_XOP_RFI     50
 #define OP_19_XOP_RFCI    51
+#define OP_19_XOP_RFDI    39
 
 #define OP_31_XOP_MFMSR   83
 #define OP_31_XOP_WRTEE   131
@@ -37,6 +38,12 @@ static void kvmppc_emul_rfi(struct kvm_vcpu *vcpu)
 	kvmppc_set_msr(vcpu, vcpu->arch.shared->srr1);
 }
 
+static void kvmppc_emul_rfdi(struct kvm_vcpu *vcpu)
+{
+	vcpu->arch.pc = vcpu->arch.dsrr0;
+	kvmppc_set_msr(vcpu, vcpu->arch.dsrr1);
+}
+
 static void kvmppc_emul_rfci(struct kvm_vcpu *vcpu)
 {
 	vcpu->arch.pc = vcpu->arch.csrr0;
@@ -65,6 +72,12 @@ int kvmppc_booke_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,
 			*advance = 0;
 			break;
 
+		case OP_19_XOP_RFDI:
+			kvmppc_emul_rfdi(vcpu);
+			kvmppc_set_exit_type(vcpu, EMULATED_RFDI_EXITS);
+			*advance = 0;
+			break;
+
 		default:
 			emulated = EMULATE_FAIL;
 			break;
-- 
1.9.3


^ permalink raw reply related	[flat|nested] 16+ messages in thread
* [PATCH 3/5] KVM: PPC: BOOKE: Allow guest to change MSR_DE
  2014-08-04  7:55 ` Bharat Bhushan
@ 2014-08-04  7:55   ` Bharat Bhushan
  -1 siblings, 0 replies; 16+ messages in thread
From: Bharat Bhushan @ 2014-08-04  7:52 UTC (permalink / raw)
  To: agraf, kvm-ppc; +Cc: kvm, scottwood, stuart.yoder, Bharat Bhushan

This patch changes the default behavior of MSRP_DEP, that is
guest is not allowed to change the MSR_DE, to guest can change
MSR_DE. When userspace is debugging guest then it override the
default behavior and set MSRP_DEP. This stops guest to change
MSR_DE when userspace is debugging guest.

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
---
 arch/powerpc/kvm/e500mc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/e500mc.c b/arch/powerpc/kvm/e500mc.c
index 164bad2..000cf82 100644
--- a/arch/powerpc/kvm/e500mc.c
+++ b/arch/powerpc/kvm/e500mc.c
@@ -194,7 +194,7 @@ int kvmppc_core_vcpu_setup(struct kvm_vcpu *vcpu)
 #ifdef CONFIG_64BIT
 	vcpu->arch.shadow_epcr |= SPRN_EPCR_ICM;
 #endif
-	vcpu->arch.shadow_msrp = MSRP_UCLEP | MSRP_DEP | MSRP_PMMP;
+	vcpu->arch.shadow_msrp = MSRP_UCLEP | MSRP_PMMP;
 	vcpu->arch.eplc = EPC_EGS | (vcpu->kvm->arch.lpid << EPC_ELPID_SHIFT);
 	vcpu->arch.epsc = vcpu->arch.eplc;
 
-- 
1.9.3

^ permalink raw reply related	[flat|nested] 16+ messages in thread
* [PATCH 4/5] KVM: PPC: BOOKE: Clear guest dbsr in userspace exit KVM_EXIT_DEBUG
  2014-08-04  7:55 ` Bharat Bhushan
@ 2014-08-04  7:55   ` Bharat Bhushan
  -1 siblings, 0 replies; 16+ messages in thread
From: Bharat Bhushan @ 2014-08-04  7:52 UTC (permalink / raw)
  To: agraf, kvm-ppc; +Cc: kvm, scottwood, stuart.yoder, Bharat Bhushan

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 not know guest ability to handle debug interrupt), so
  userspace will always clear DBSR.
  Now if userspace has to always clear DBSR in KVM_EXIT_DEBUG
  handling then clearing dbsr in kernel looks simple as this
  avoid doing SET_SREGS/set_one_reg() to clear DBSR

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
---
 arch/powerpc/kvm/booke.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 322da7d..5c2e26a 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -735,6 +735,17 @@ 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).
+	 * 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
+	 * not know guest ability to handle debug interrupt), so userspace
+	 * will always clear DBSR.
+	 * Now if userspace has to always clear DBSR in KVM_EXIT_DEBUG
+	 * handling then clearing here looks simple as this
+	 * avoid doing SET_SREGS/set_one_reg() to clear DBSR
+	 */
+	vcpu->arch.dbsr = 0;
 	run->debug.arch.status = 0;
 	run->debug.arch.address = vcpu->arch.pc;
 
-- 
1.9.3

^ permalink raw reply related	[flat|nested] 16+ messages in thread
* [PATCH 5/5] KVM: PPC: BOOKE: Emulate debug registers and exception
  2014-08-04  7:55 ` Bharat Bhushan
@ 2014-08-04  7:55   ` Bharat Bhushan
  -1 siblings, 0 replies; 16+ messages in thread
From: Bharat Bhushan @ 2014-08-04  7:52 UTC (permalink / raw)
  To: agraf, kvm-ppc; +Cc: kvm, scottwood, stuart.yoder, Bharat Bhushan

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@freescale.com>
---
 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

^ permalink raw reply related	[flat|nested] 16+ messages in thread
* [PATCH 3/5] KVM: PPC: BOOKE: Allow guest to change MSR_DE
@ 2014-08-04  7:55   ` Bharat Bhushan
  0 siblings, 0 replies; 16+ messages in thread
From: Bharat Bhushan @ 2014-08-04  7:55 UTC (permalink / raw)
  To: agraf, kvm-ppc; +Cc: kvm, scottwood, stuart.yoder, Bharat Bhushan

This patch changes the default behavior of MSRP_DEP, that is
guest is not allowed to change the MSR_DE, to guest can change
MSR_DE. When userspace is debugging guest then it override the
default behavior and set MSRP_DEP. This stops guest to change
MSR_DE when userspace is debugging guest.

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
---
 arch/powerpc/kvm/e500mc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/e500mc.c b/arch/powerpc/kvm/e500mc.c
index 164bad2..000cf82 100644
--- a/arch/powerpc/kvm/e500mc.c
+++ b/arch/powerpc/kvm/e500mc.c
@@ -194,7 +194,7 @@ int kvmppc_core_vcpu_setup(struct kvm_vcpu *vcpu)
 #ifdef CONFIG_64BIT
 	vcpu->arch.shadow_epcr |= SPRN_EPCR_ICM;
 #endif
-	vcpu->arch.shadow_msrp = MSRP_UCLEP | MSRP_DEP | MSRP_PMMP;
+	vcpu->arch.shadow_msrp = MSRP_UCLEP | MSRP_PMMP;
 	vcpu->arch.eplc = EPC_EGS | (vcpu->kvm->arch.lpid << EPC_ELPID_SHIFT);
 	vcpu->arch.epsc = vcpu->arch.eplc;
 
-- 
1.9.3


^ permalink raw reply related	[flat|nested] 16+ messages in thread
* [PATCH 5/5] KVM: PPC: BOOKE: Emulate debug registers and exception
@ 2014-08-04  7:55   ` Bharat Bhushan
  0 siblings, 0 replies; 16+ messages in thread
From: Bharat Bhushan @ 2014-08-04  7:55 UTC (permalink / raw)
  To: agraf, kvm-ppc; +Cc: kvm, scottwood, stuart.yoder, Bharat Bhushan

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@freescale.com>
---
 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


^ permalink raw reply related	[flat|nested] 16+ messages in thread
* [PATCH 1/5] KVM: PPC: BOOKE: allow debug interrupt at "debug level"
@ 2014-08-04  7:55 ` Bharat Bhushan
  0 siblings, 0 replies; 16+ messages in thread
From: Bharat Bhushan @ 2014-08-04  7:55 UTC (permalink / raw)
  To: agraf, kvm-ppc; +Cc: kvm, scottwood, stuart.yoder, Bharat Bhushan

Debug interrupt can be either "critical level" or "debug level".
There are separate set of save/restore registers used for different level.
Example: DSRR0/DSRR1 are used for "debug level" and CSRR0/CSRR1
are used for critical level debug interrupt.

Using CPU_FTR_DEBUG_LVL_EXC to decide which interrupt level to be used.

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
---
 arch/powerpc/kvm/booke.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index b4c89fa..322da7d 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -377,7 +377,11 @@ static int kvmppc_booke_irqprio_deliver(struct kvm_vcpu *vcpu,
 		allowed = vcpu->arch.shared->msr & MSR_DE;
 		allowed = allowed && !crit;
 		msr_mask = MSR_ME;
-		int_class = INT_CLASS_CRIT;
+		if (cpu_has_feature(CPU_FTR_DEBUG_LVL_EXC))
+			int_class = INT_CLASS_DBG;
+		else
+			int_class = INT_CLASS_CRIT;
+
 		break;
 	}
 
-- 
1.9.3


^ permalink raw reply related	[flat|nested] 16+ messages in thread
* [PATCH 4/5] KVM: PPC: BOOKE: Clear guest dbsr in userspace exit KVM_EXIT_DEBUG
@ 2014-08-04  7:55   ` Bharat Bhushan
  0 siblings, 0 replies; 16+ messages in thread
From: Bharat Bhushan @ 2014-08-04  7:55 UTC (permalink / raw)
  To: agraf, kvm-ppc; +Cc: kvm, scottwood, stuart.yoder, Bharat Bhushan

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 not know guest ability to handle debug interrupt), so
  userspace will always clear DBSR.
  Now if userspace has to always clear DBSR in KVM_EXIT_DEBUG
  handling then clearing dbsr in kernel looks simple as this
  avoid doing SET_SREGS/set_one_reg() to clear DBSR

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
---
 arch/powerpc/kvm/booke.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 322da7d..5c2e26a 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -735,6 +735,17 @@ 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).
+	 * 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
+	 * not know guest ability to handle debug interrupt), so userspace
+	 * will always clear DBSR.
+	 * Now if userspace has to always clear DBSR in KVM_EXIT_DEBUG
+	 * handling then clearing here looks simple as this
+	 * avoid doing SET_SREGS/set_one_reg() to clear DBSR
+	 */
+	vcpu->arch.dbsr = 0;
 	run->debug.arch.status = 0;
 	run->debug.arch.address = vcpu->arch.pc;
 
-- 
1.9.3


^ permalink raw reply related	[flat|nested] 16+ messages in thread
* [PATCH 2/5] KVM: PPC: BOOKE : Emulate rfdi instruction
@ 2014-08-04  7:55   ` Bharat Bhushan
  0 siblings, 0 replies; 16+ messages in thread
From: Bharat Bhushan @ 2014-08-04  7:55 UTC (permalink / raw)
  To: agraf, kvm-ppc; +Cc: kvm, scottwood, stuart.yoder, Bharat Bhushan

This patch adds "rfdi" instruction emulation which is required for
guest debug hander on BOOKE-HV

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
---
 arch/powerpc/include/asm/kvm_host.h |  1 +
 arch/powerpc/kvm/booke_emulate.c    | 13 +++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 98d9dd5..636b230 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -144,6 +144,7 @@ enum kvm_exit_types {
 	EMULATED_TLBWE_EXITS,
 	EMULATED_RFI_EXITS,
 	EMULATED_RFCI_EXITS,
+	EMULATED_RFDI_EXITS,
 	DEC_EXITS,
 	EXT_INTR_EXITS,
 	HALT_WAKEUP,
diff --git a/arch/powerpc/kvm/booke_emulate.c b/arch/powerpc/kvm/booke_emulate.c
index 28c1588..4b9a079 100644
--- a/arch/powerpc/kvm/booke_emulate.c
+++ b/arch/powerpc/kvm/booke_emulate.c
@@ -25,6 +25,7 @@
 
 #define OP_19_XOP_RFI     50
 #define OP_19_XOP_RFCI    51
+#define OP_19_XOP_RFDI    39
 
 #define OP_31_XOP_MFMSR   83
 #define OP_31_XOP_WRTEE   131
@@ -37,6 +38,12 @@ static void kvmppc_emul_rfi(struct kvm_vcpu *vcpu)
 	kvmppc_set_msr(vcpu, vcpu->arch.shared->srr1);
 }
 
+static void kvmppc_emul_rfdi(struct kvm_vcpu *vcpu)
+{
+	vcpu->arch.pc = vcpu->arch.dsrr0;
+	kvmppc_set_msr(vcpu, vcpu->arch.dsrr1);
+}
+
 static void kvmppc_emul_rfci(struct kvm_vcpu *vcpu)
 {
 	vcpu->arch.pc = vcpu->arch.csrr0;
@@ -65,6 +72,12 @@ int kvmppc_booke_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,
 			*advance = 0;
 			break;
 
+		case OP_19_XOP_RFDI:
+			kvmppc_emul_rfdi(vcpu);
+			kvmppc_set_exit_type(vcpu, EMULATED_RFDI_EXITS);
+			*advance = 0;
+			break;
+
 		default:
 			emulated = EMULATE_FAIL;
 			break;
-- 
1.9.3


^ permalink raw reply related	[flat|nested] 16+ messages in thread
* Re: [PATCH 4/5] KVM: PPC: BOOKE: Clear guest dbsr in userspace exit KVM_EXIT_DEBUG
  2014-08-04  7:55   ` Bharat Bhushan
@ 2014-08-04 22:46     ` Scott Wood
  -1 siblings, 0 replies; 16+ messages in thread
From: Scott Wood @ 2014-08-04 22:46 UTC (permalink / raw)
  To: Bharat Bhushan; +Cc: agraf, kvm-ppc, kvm, stuart.yoder

On Mon, 2014-08-04 at 13:22 +0530, Bharat Bhushan wrote:
> 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 not know guest ability to handle debug interrupt), so
>   userspace will always clear DBSR.
>   Now if userspace has to always clear DBSR in KVM_EXIT_DEBUG
>   handling then clearing dbsr in kernel looks simple as this
>   avoid doing SET_SREGS/set_one_reg() to clear DBSR
> 
> Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
> ---
>  arch/powerpc/kvm/booke.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
> index 322da7d..5c2e26a 100644
> --- a/arch/powerpc/kvm/booke.c
> +++ b/arch/powerpc/kvm/booke.c
> @@ -735,6 +735,17 @@ 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).
> +	 * 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
> +	 * not know guest ability to handle debug interrupt), so userspace
> +	 * will always clear DBSR.
> +	 * Now if userspace has to always clear DBSR in KVM_EXIT_DEBUG
> +	 * handling then clearing here looks simple as this
> +	 * avoid doing SET_SREGS/set_one_reg() to clear DBSR
> +	 */
> +	vcpu->arch.dbsr = 0;
>  	run->debug.arch.status = 0;
>  	run->debug.arch.address = vcpu->arch.pc;
>  

I think the changelog is adequate -- I don't think we need to be so
verbose in the code itself.  The question was just whether this was a
userspace-visible change, and it isn't.

FWIW, I think dbsr should be visible to userspace in general (regardless
of whether it's cleared here), because all guest registers should be
visible to userspace.  I may be debugging a guest through means that
don't require owning debug resources, such as stopping and inspecting a
guest that has hung or crashed.

-Scott

^ permalink raw reply	[flat|nested] 16+ messages in thread
* Re: [PATCH 4/5] KVM: PPC: BOOKE: Clear guest dbsr in userspace exit KVM_EXIT_DEBUG
@ 2014-08-04 22:46     ` Scott Wood
  0 siblings, 0 replies; 16+ messages in thread
From: Scott Wood @ 2014-08-04 22:46 UTC (permalink / raw)
  To: Bharat Bhushan; +Cc: agraf, kvm-ppc, kvm, stuart.yoder

On Mon, 2014-08-04 at 13:22 +0530, Bharat Bhushan wrote:
> 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 not know guest ability to handle debug interrupt), so
>   userspace will always clear DBSR.
>   Now if userspace has to always clear DBSR in KVM_EXIT_DEBUG
>   handling then clearing dbsr in kernel looks simple as this
>   avoid doing SET_SREGS/set_one_reg() to clear DBSR
> 
> Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
> ---
>  arch/powerpc/kvm/booke.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
> index 322da7d..5c2e26a 100644
> --- a/arch/powerpc/kvm/booke.c
> +++ b/arch/powerpc/kvm/booke.c
> @@ -735,6 +735,17 @@ 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).
> +	 * 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
> +	 * not know guest ability to handle debug interrupt), so userspace
> +	 * will always clear DBSR.
> +	 * Now if userspace has to always clear DBSR in KVM_EXIT_DEBUG
> +	 * handling then clearing here looks simple as this
> +	 * avoid doing SET_SREGS/set_one_reg() to clear DBSR
> +	 */
> +	vcpu->arch.dbsr = 0;
>  	run->debug.arch.status = 0;
>  	run->debug.arch.address = vcpu->arch.pc;
>  

I think the changelog is adequate -- I don't think we need to be so
verbose in the code itself.  The question was just whether this was a
userspace-visible change, and it isn't.

FWIW, I think dbsr should be visible to userspace in general (regardless
of whether it's cleared here), because all guest registers should be
visible to userspace.  I may be debugging a guest through means that
don't require owning debug resources, such as stopping and inspecting a
guest that has hung or crashed.

-Scott



^ permalink raw reply	[flat|nested] 16+ messages in thread
* RE: [PATCH 4/5] KVM: PPC: BOOKE: Clear guest dbsr in userspace exit KVM_EXIT_DEBUG
  2014-08-04 22:46     ` Scott Wood
@ 2014-08-05  3:33       ` Bharat.Bhushan
  -1 siblings, 0 replies; 16+ messages in thread
From: Bharat.Bhushan @ 2014-08-05  3:33 UTC (permalink / raw)
  To: Scott Wood; +Cc: agraf, kvm-ppc, kvm, Stuart Yoder



> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Tuesday, August 05, 2014 4:17 AM
> To: Bhushan Bharat-R65777
> Cc: agraf@suse.de; kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; Yoder Stuart-
> B08248
> Subject: Re: [PATCH 4/5] KVM: PPC: BOOKE: Clear guest dbsr in userspace exit
> KVM_EXIT_DEBUG
> 
> On Mon, 2014-08-04 at 13:22 +0530, Bharat Bhushan wrote:
> > 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 not know guest ability to handle debug interrupt), so
> >   userspace will always clear DBSR.
> >   Now if userspace has to always clear DBSR in KVM_EXIT_DEBUG
> >   handling then clearing dbsr in kernel looks simple as this
> >   avoid doing SET_SREGS/set_one_reg() to clear DBSR
> >
> > Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
> > ---
> >  arch/powerpc/kvm/booke.c | 11 +++++++++++
> >  1 file changed, 11 insertions(+)
> >
> > diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c index
> > 322da7d..5c2e26a 100644
> > --- a/arch/powerpc/kvm/booke.c
> > +++ b/arch/powerpc/kvm/booke.c
> > @@ -735,6 +735,17 @@ 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).
> > +	 * 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
> > +	 * not know guest ability to handle debug interrupt), so userspace
> > +	 * will always clear DBSR.
> > +	 * Now if userspace has to always clear DBSR in KVM_EXIT_DEBUG
> > +	 * handling then clearing here looks simple as this
> > +	 * avoid doing SET_SREGS/set_one_reg() to clear DBSR
> > +	 */
> > +	vcpu->arch.dbsr = 0;
> >  	run->debug.arch.status = 0;
> >  	run->debug.arch.address = vcpu->arch.pc;
> >
> 
> I think the changelog is adequate -- I don't think we need to be so verbose in
> the code itself.  The question was just whether this was a userspace-visible
> change, and it isn't.

Ok, will make a small comment.

> 
> FWIW, I think dbsr should be visible to userspace in general (regardless of
> whether it's cleared here), because all guest registers should be visible to
> userspace.  I may be debugging a guest through means that don't require owning
> debug resources, such as stopping and inspecting a guest that has hung or
> crashed.

Do you mean that we should also add a one-reg interface for DBSR ?

Thanks
-Bharat

> 
> -Scott
> 


^ permalink raw reply	[flat|nested] 16+ messages in thread
* RE: [PATCH 4/5] KVM: PPC: BOOKE: Clear guest dbsr in userspace exit KVM_EXIT_DEBUG
@ 2014-08-05  3:33       ` Bharat.Bhushan
  0 siblings, 0 replies; 16+ messages in thread
From: Bharat.Bhushan @ 2014-08-05  3:33 UTC (permalink / raw)
  To: Scott Wood; +Cc: agraf, kvm-ppc, kvm, Stuart Yoder

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^ permalink raw reply	[flat|nested] 16+ messages in thread
* Re: [PATCH 4/5] KVM: PPC: BOOKE: Clear guest dbsr in userspace exit KVM_EXIT_DEBUG
  2014-08-05  3:33       ` Bharat.Bhushan
@ 2014-08-05  3:36         ` Scott Wood
  -1 siblings, 0 replies; 16+ messages in thread
From: Scott Wood @ 2014-08-05  3:36 UTC (permalink / raw)
  To: Bhushan Bharat-R65777; +Cc: agraf, kvm-ppc, kvm, Yoder Stuart-B08248

On Mon, 2014-08-04 at 22:33 -0500, Bhushan Bharat-R65777 wrote:
> 
> > -----Original Message-----
> > From: Wood Scott-B07421
> > Sent: Tuesday, August 05, 2014 4:17 AM
> > To: Bhushan Bharat-R65777
> > Cc: agraf@suse.de; kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; Yoder Stuart-
> > B08248
> > Subject: Re: [PATCH 4/5] KVM: PPC: BOOKE: Clear guest dbsr in userspace exit
> > KVM_EXIT_DEBUG
> > 
> > FWIW, I think dbsr should be visible to userspace in general (regardless of
> > whether it's cleared here), because all guest registers should be visible to
> > userspace.  I may be debugging a guest through means that don't require owning
> > debug resources, such as stopping and inspecting a guest that has hung or
> > crashed.
> 
> Do you mean that we should also add a one-reg interface for DBSR ?

Yes.

-Scott



^ permalink raw reply	[flat|nested] 16+ messages in thread
* Re: [PATCH 4/5] KVM: PPC: BOOKE: Clear guest dbsr in userspace exit KVM_EXIT_DEBUG
@ 2014-08-05  3:36         ` Scott Wood
  0 siblings, 0 replies; 16+ messages in thread
From: Scott Wood @ 2014-08-05  3:36 UTC (permalink / raw)
  To: Bhushan Bharat-R65777; +Cc: agraf, kvm-ppc, kvm, Yoder Stuart-B08248

On Mon, 2014-08-04 at 22:33 -0500, Bhushan Bharat-R65777 wrote:
> 
> > -----Original Message-----
> > From: Wood Scott-B07421
> > Sent: Tuesday, August 05, 2014 4:17 AM
> > To: Bhushan Bharat-R65777
> > Cc: agraf@suse.de; kvm-ppc@vger.kernel.org; kvm@vger.kernel.org; Yoder Stuart-
> > B08248
> > Subject: Re: [PATCH 4/5] KVM: PPC: BOOKE: Clear guest dbsr in userspace exit
> > KVM_EXIT_DEBUG
> > 
> > FWIW, I think dbsr should be visible to userspace in general (regardless of
> > whether it's cleared here), because all guest registers should be visible to
> > userspace.  I may be debugging a guest through means that don't require owning
> > debug resources, such as stopping and inspecting a guest that has hung or
> > crashed.
> 
> Do you mean that we should also add a one-reg interface for DBSR ?

Yes.

-Scott



^ permalink raw reply	[flat|nested] 16+ messages in thread
end of thread, other threads:[~2014-08-05  3:36 UTC | newest]

Thread overview: 16+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-08-04  7:52 [PATCH 1/5] KVM: PPC: BOOKE: allow debug interrupt at "debug level" Bharat Bhushan
2014-08-04  7:55 ` Bharat Bhushan
2014-08-04  7:52 ` [PATCH 2/5] KVM: PPC: BOOKE : Emulate rfdi instruction Bharat Bhushan
2014-08-04  7:55   ` Bharat Bhushan
2014-08-04  7:52 ` [PATCH 3/5] KVM: PPC: BOOKE: Allow guest to change MSR_DE Bharat Bhushan
2014-08-04  7:55   ` Bharat Bhushan
2014-08-04  7:52 ` [PATCH 4/5] KVM: PPC: BOOKE: Clear guest dbsr in userspace exit KVM_EXIT_DEBUG Bharat Bhushan
2014-08-04  7:55   ` Bharat Bhushan
2014-08-04 22:46   ` Scott Wood
2014-08-04 22:46     ` Scott Wood
2014-08-05  3:33     ` Bharat.Bhushan
2014-08-05  3:33       ` Bharat.Bhushan
2014-08-05  3:36       ` Scott Wood
2014-08-05  3:36         ` Scott Wood
2014-08-04  7:52 ` [PATCH 5/5] KVM: PPC: BOOKE: Emulate debug registers and exception Bharat Bhushan
2014-08-04  7:55   ` Bharat Bhushan

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