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.bhus...@freescale.com
---
v2-v3
- Corrected no debug interrupt if only DBSR_IDE event set
- DBSR_MRR cleanup on kvm init
- no arch-shadow_dbg_reg as per previous patch
arch/powerpc/include/asm/kvm_ppc.h | 3 +
arch/powerpc/include/asm/reg_booke.h | 2 +
arch/powerpc/kvm/booke.c | 38 -
arch/powerpc/kvm/booke_emulate.c | 148 +++
4 files changed, 190 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 0x8000 /* Imprecise Debug Event */
+#define DBSR_MRR 0x3000 /* Most Recent Reset */
#define DBSR_IC0x0800 /* Instruction Completion */
#define DBSR_BT0x0400 /* Branch Taken */
#define DBSR_IRPT 0x0200 /* Exception Debug Event */
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 074b7fc..02d3677 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 +745,32 @@ static int kvmppc_handle_debug(struct kvm_run *run, struct
kvm_vcpu *vcpu)
struct debug_reg *dbg_reg = (vcpu-arch.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 is not injected
+*/
+ if (dbsr DBSR_IDE) {
+ dbsr = ~DBSR_IDE;
+ if (!dbsr)
+ 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)
+*/
vcpu-arch.dbsr = 0;
run-debug.arch.status = 0;
run-debug.arch.address = vcpu-arch.pc;
@@ -1249,6 +1284,7 @@ int kvmppc_subarch_vcpu_init(struct kvm_vcpu *vcpu)
setup_timer(vcpu-arch.wdt_timer, kvmppc_watchdog_func,
(unsigned long)vcpu);
+ kvmppc_clear_dbsr();
return 0;
}
diff --git a/arch/powerpc/kvm/booke_emulate.c b/arch/powerpc/kvm/booke_emulate.c
index 92bc668..a82f645 100644
---
