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Subject[PATCH v5 12/12] KVM: arm64: add trace points for guest_debug debug
Date
This includes trace points for:
kvm_arch_setup_guest_debug
kvm_arch_clear_guest_debug

I've also added some generic register setting trace events and also a
trace point to dump the array of hardware registers.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

---
v3
- add trace event for debug access.
- remove short trace #define, rename trace events
- use __print_array with fixed array instead of own func
- rationalise trace points (only one per register changed)
- add vcpu ptr to the debug_setup trace
- remove :: in prints
v4
- u32/u64 split on debug registers
- fix for renames
- add tracing of traps/set_guest_debug
- remove handle_guest_debug trace
v5
- minor print fmt fix
- rm pstate traces
---
arch/arm/kvm/arm.c | 2 +
arch/arm/kvm/trace.h | 17 ++++++++
arch/arm64/kvm/debug.c | 35 +++++++++++++++-
arch/arm64/kvm/sys_regs.c | 10 +++++
arch/arm64/kvm/trace.h | 105 ++++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 168 insertions(+), 1 deletion(-)

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 6df47c1..a939a4e 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -323,6 +323,8 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
struct kvm_guest_debug *dbg)
{
+ trace_kvm_set_guest_debug(vcpu, dbg->control);
+
if (dbg->control & ~KVM_GUESTDBG_VALID_MASK)
return -EINVAL;

diff --git a/arch/arm/kvm/trace.h b/arch/arm/kvm/trace.h
index 0ec3539..3e346a6 100644
--- a/arch/arm/kvm/trace.h
+++ b/arch/arm/kvm/trace.h
@@ -317,6 +317,23 @@ TRACE_EVENT(kvm_toggle_cache,
__entry->now ? "on" : "off")
);

+TRACE_EVENT(kvm_set_guest_debug,
+ TP_PROTO(struct kvm_vcpu *vcpu, __u32 guest_debug),
+ TP_ARGS(vcpu, guest_debug),
+
+ TP_STRUCT__entry(
+ __field(struct kvm_vcpu *, vcpu)
+ __field(__u32, guest_debug)
+ ),
+
+ TP_fast_assign(
+ __entry->vcpu = vcpu;
+ __entry->guest_debug = guest_debug;
+ ),
+
+ TP_printk("vcpu: %p, flags: 0x%08x", __entry->vcpu, __entry->guest_debug)
+);
+
#endif /* _TRACE_KVM_H */

#undef TRACE_INCLUDE_PATH
diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c
index 3c0daae..97204b5 100644
--- a/arch/arm64/kvm/debug.c
+++ b/arch/arm64/kvm/debug.c
@@ -24,6 +24,8 @@
#include <asm/kvm_arm.h>
#include <asm/kvm_emulate.h>

+#include "trace.h"
+
/* These are the bits of MDSCR_EL1 we may manipulate */
#define MDSCR_EL1_DEBUG_MASK (DBG_MDSCR_SS | \
DBG_MDSCR_KDE | \
@@ -46,11 +48,17 @@ static DEFINE_PER_CPU(u32, mdcr_el2);
static void save_guest_debug_regs(struct kvm_vcpu *vcpu)
{
vcpu->arch.guest_debug_preserved.mdscr_el1 = vcpu_sys_reg(vcpu, MDSCR_EL1);
+
+ trace_kvm_arm_set_dreg32("Saved MDSCR_EL1",
+ vcpu->arch.guest_debug_preserved.mdscr_el1);
}

static void restore_guest_debug_regs(struct kvm_vcpu *vcpu)
{
vcpu_sys_reg(vcpu, MDSCR_EL1) = vcpu->arch.guest_debug_preserved.mdscr_el1;
+
+ trace_kvm_arm_set_dreg32("Restored MDSCR_EL1",
+ vcpu_sys_reg(vcpu, MDSCR_EL1));
}

/**
@@ -92,6 +100,8 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
{
bool trap_debug = !(vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY);

+ trace_kvm_arm_setup_debug(vcpu, vcpu->guest_debug);
+
vcpu->arch.mdcr_el2 = __this_cpu_read(mdcr_el2) & MDCR_EL2_HPMN_MASK;
vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM |
MDCR_EL2_TPMCR |
@@ -121,6 +131,8 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
vcpu_sys_reg(vcpu, MDSCR_EL1) &= ~DBG_MDSCR_SS;
}

+ trace_kvm_arm_set_dreg32("SPSR_EL2", *vcpu_cpsr(vcpu));
+
/*
* HW Break/Watch points
*
@@ -137,16 +149,29 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
vcpu->arch.debug_ptr = &vcpu->arch.external_debug_state;
vcpu->arch.debug_flags |= KVM_ARM64_DEBUG_DIRTY;
trap_debug = true;
+
+ trace_kvm_arm_set_regset("BKPTS", get_num_brps(),
+ &vcpu->arch.debug_ptr->dbg_bcr[0],
+ &vcpu->arch.debug_ptr->dbg_bvr[0]);
+
+ trace_kvm_arm_set_regset("WAPTS", get_num_wrps(),
+ &vcpu->arch.debug_ptr->dbg_wcr[0],
+ &vcpu->arch.debug_ptr->dbg_wvr[0]);
}
}

/* Trap debug register access */
if (trap_debug)
vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA;
+
+ trace_kvm_arm_set_dreg32("MDCR_EL2", vcpu->arch.mdcr_el2);
+ trace_kvm_arm_set_dreg32("MDSCR_EL1", vcpu_sys_reg(vcpu, MDSCR_EL1));
}

void kvm_arm_clear_debug(struct kvm_vcpu *vcpu)
{
+ trace_kvm_arm_clear_debug(vcpu->guest_debug);
+
if (vcpu->guest_debug) {
restore_guest_debug_regs(vcpu);

@@ -154,8 +179,16 @@ void kvm_arm_clear_debug(struct kvm_vcpu *vcpu)
* If we were using HW debug we need to restore the
* debug_ptr to the guest debug state.
*/
- if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
+ if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
vcpu->arch.debug_ptr = &vcpu->arch.vcpu_debug_state;

+ trace_kvm_arm_set_regset("BKPTS", get_num_brps(),
+ &vcpu->arch.debug_ptr->dbg_bcr[0],
+ &vcpu->arch.debug_ptr->dbg_bvr[0]);
+
+ trace_kvm_arm_set_regset("WAPTS", get_num_wrps(),
+ &vcpu->arch.debug_ptr->dbg_wcr[0],
+ &vcpu->arch.debug_ptr->dbg_wvr[0]);
+ }
}
}
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 405403e..15bc851 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -38,6 +38,8 @@

#include "sys_regs.h"

+#include "trace.h"
+
/*
* All of this file is extremly similar to the ARM coproc.c, but the
* types are different. My gut feeling is that it should be pretty
@@ -208,6 +210,8 @@ static bool trap_debug_regs(struct kvm_vcpu *vcpu,
*vcpu_reg(vcpu, p->Rt) = vcpu_sys_reg(vcpu, r->reg);
}

+ trace_trap_reg(__func__, r->reg, p->is_write, *vcpu_reg(vcpu, p->Rt));
+
return true;
}

@@ -223,6 +227,8 @@ static inline bool trap_debug32(struct kvm_vcpu *vcpu,
*vcpu_reg(vcpu, p->Rt) = *r;
}

+ trace_trap_reg(__func__, rd->reg, p->is_write, *r);
+
return true;
}

@@ -238,6 +244,8 @@ static inline bool trap_debug64(struct kvm_vcpu *vcpu,
*vcpu_reg(vcpu, p->Rt) = *r;
}

+ trace_trap_reg(__func__, rd->reg, p->is_write, *r);
+
return true;
}

@@ -1031,6 +1039,8 @@ int kvm_handle_sys_reg(struct kvm_vcpu *vcpu, struct kvm_run *run)
struct sys_reg_params params;
unsigned long esr = kvm_vcpu_get_hsr(vcpu);

+ trace_kvm_handle_sys_reg(esr);
+
params.is_aarch32 = false;
params.is_32bit = false;
params.Op0 = (esr >> 20) & 3;
diff --git a/arch/arm64/kvm/trace.h b/arch/arm64/kvm/trace.h
index 157416e9..5122a55 100644
--- a/arch/arm64/kvm/trace.h
+++ b/arch/arm64/kvm/trace.h
@@ -44,6 +44,111 @@ TRACE_EVENT(kvm_hvc_arm64,
__entry->vcpu_pc, __entry->r0, __entry->imm)
);

+TRACE_EVENT(kvm_arm_setup_debug,
+ TP_PROTO(struct kvm_vcpu *vcpu, __u32 guest_debug),
+ TP_ARGS(vcpu, guest_debug),
+
+ TP_STRUCT__entry(
+ __field(struct kvm_vcpu *, vcpu)
+ __field(__u32, guest_debug)
+ ),
+
+ TP_fast_assign(
+ __entry->vcpu = vcpu;
+ __entry->guest_debug = guest_debug;
+ ),
+
+ TP_printk("vcpu: %p, flags: 0x%08x", __entry->vcpu, __entry->guest_debug)
+);
+
+TRACE_EVENT(kvm_arm_clear_debug,
+ TP_PROTO(__u32 guest_debug),
+ TP_ARGS(guest_debug),
+
+ TP_STRUCT__entry(
+ __field(__u32, guest_debug)
+ ),
+
+ TP_fast_assign(
+ __entry->guest_debug = guest_debug;
+ ),
+
+ TP_printk("flags: 0x%08x", __entry->guest_debug)
+);
+
+TRACE_EVENT(kvm_arm_set_dreg32,
+ TP_PROTO(const char *name, __u32 value),
+ TP_ARGS(name, value),
+
+ TP_STRUCT__entry(
+ __field(const char *, name)
+ __field(__u32, value)
+ ),
+
+ TP_fast_assign(
+ __entry->name = name;
+ __entry->value = value;
+ ),
+
+ TP_printk("%s: 0x%08x", __entry->name, __entry->value)
+);
+
+TRACE_EVENT(kvm_arm_set_regset,
+ TP_PROTO(const char *type, int len, __u32 *control, __u64 *value),
+ TP_ARGS(type, len, control, value),
+ TP_STRUCT__entry(
+ __field(const char *, name)
+ __field(int, len)
+ __array(u32, ctrls, 16)
+ __array(u64, values, 16)
+ ),
+ TP_fast_assign(
+ __entry->name = type;
+ __entry->len = len;
+ memcpy(__entry->ctrls, control, len << 2);
+ memcpy(__entry->values, value, len << 3);
+ ),
+ TP_printk("%d %s CTRL:%s VALUE:%s", __entry->len, __entry->name,
+ __print_array(__entry->ctrls, __entry->len, sizeof(__u32)),
+ __print_array(__entry->values, __entry->len, sizeof(__u64)))
+);
+
+TRACE_EVENT(trap_reg,
+ TP_PROTO(const char *fn, int reg, bool is_write, u64 write_value),
+ TP_ARGS(fn, reg, is_write, write_value),
+
+ TP_STRUCT__entry(
+ __field(const char *, fn)
+ __field(int, reg)
+ __field(bool, is_write)
+ __field(u64, write_value)
+ ),
+
+ TP_fast_assign(
+ __entry->fn = fn;
+ __entry->reg = reg;
+ __entry->is_write = is_write;
+ __entry->write_value = write_value;
+ ),
+
+ TP_printk("%s %s reg %d (0x%08llx)", __entry->fn, __entry->is_write?"write to":"read from", __entry->reg, __entry->write_value)
+);
+
+TRACE_EVENT(kvm_handle_sys_reg,
+ TP_PROTO(unsigned long hsr),
+ TP_ARGS(hsr),
+
+ TP_STRUCT__entry(
+ __field(unsigned long, hsr)
+ ),
+
+ TP_fast_assign(
+ __entry->hsr = hsr;
+ ),
+
+ TP_printk("HSR 0x%08lx", __entry->hsr)
+);
+
#endif /* _TRACE_ARM64_KVM_H */

#undef TRACE_INCLUDE_PATH
--
2.4.1


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