Commit 2194d317 authored by Vincent Donnefort's avatar Vincent Donnefort Committed by Marc Zyngier
Browse files

KVM: arm64: Add trace reset to the nVHE/pKVM hyp 



Make the hypervisor reset either the whole tracing buffer or a specific
ring-buffer, on remotes/hypervisor/trace or per_cpu/<cpu>/trace write
access.

Signed-off-by: default avatarVincent Donnefort <vdonnefort@google.com>
Link: https://patch.msgid.link/20260309162516.2623589-27-vdonnefort@google.com


Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent b2288891

arch/arm64/include/asm/kvm_asm.h

+1 −0
Original line number Diff line number Diff line
@@ -94,6 +94,7 @@ enum __kvm_host_smccc_func { 
	__KVM_HOST_SMCCC_FUNC___tracing_enable,

	__KVM_HOST_SMCCC_FUNC___tracing_swap_reader,

	__KVM_HOST_SMCCC_FUNC___tracing_update_clock,

	__KVM_HOST_SMCCC_FUNC___tracing_reset,

};



#define DECLARE_KVM_VHE_SYM(sym)	extern char sym[]

arch/arm64/kvm/hyp/include/nvhe/trace.h

+2 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ void __tracing_unload(void); 
int __tracing_enable(bool enable);

int __tracing_swap_reader(unsigned int cpu);

void __tracing_update_clock(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc);

int __tracing_reset(unsigned int cpu);

#else

static inline void *tracing_reserve_entry(unsigned long length) { return NULL; }

static inline void tracing_commit_entry(void) { }
@@ -21,5 +22,6 @@ static inline void __tracing_unload(void) { } 
static inline int __tracing_enable(bool enable) { return -ENODEV; }

static inline int __tracing_swap_reader(unsigned int cpu) { return -ENODEV; }

static inline void __tracing_update_clock(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc) { }

static inline int __tracing_reset(unsigned int cpu) { return -ENODEV; }

#endif

#endif

arch/arm64/kvm/hyp/nvhe/hyp-main.c

+8 −0
Original line number Diff line number Diff line
@@ -625,6 +625,13 @@ static void handle___tracing_update_clock(struct kvm_cpu_context *host_ctxt) 
	__tracing_update_clock(mult, shift, epoch_ns, epoch_cyc);

}



static void handle___tracing_reset(struct kvm_cpu_context *host_ctxt)

{

	DECLARE_REG(unsigned int, cpu, host_ctxt, 1);



	cpu_reg(host_ctxt, 1) = __tracing_reset(cpu);

}



typedef void (*hcall_t)(struct kvm_cpu_context *);



#define HANDLE_FUNC(x)	[__KVM_HOST_SMCCC_FUNC_##x] = (hcall_t)handle_##x
@@ -671,6 +678,7 @@ static const hcall_t host_hcall[] = { 
	HANDLE_FUNC(__tracing_enable),

	HANDLE_FUNC(__tracing_swap_reader),

	HANDLE_FUNC(__tracing_update_clock),

	HANDLE_FUNC(__tracing_reset),

};



static void handle_host_hcall(struct kvm_cpu_context *host_ctxt)

arch/arm64/kvm/hyp/nvhe/trace.c

+17 −0
Original line number Diff line number Diff line
@@ -287,3 +287,20 @@ void __tracing_update_clock(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc) 
	/* ...we can now override the old one and swap. */

	trace_clock_update(mult, shift, epoch_ns, epoch_cyc);

}



int __tracing_reset(unsigned int cpu)

{

	int ret = -ENODEV;



	if (cpu >= hyp_nr_cpus)

		return -EINVAL;



	hyp_spin_lock(&trace_buffer.lock);



	if (hyp_trace_buffer_loaded(&trace_buffer))

		ret = simple_ring_buffer_reset(per_cpu_ptr(trace_buffer.simple_rbs, cpu));



	hyp_spin_unlock(&trace_buffer.lock);



	return ret;

}

arch/arm64/kvm/hyp_trace.c

+1 −1
Original line number Diff line number Diff line
@@ -313,7 +313,7 @@ static int hyp_trace_swap_reader_page(unsigned int cpu, void *priv) 


static int hyp_trace_reset(unsigned int cpu, void *priv)

{

	return 0;

	return kvm_call_hyp_nvhe(__tracing_reset, cpu);

}



static int hyp_trace_enable_event(unsigned short id, bool enable, void *priv)