Commit 38131c02 authored by Oliver Upton's avatar Oliver Upton Committed by Marc Zyngier
Browse files

KVM: arm64: Track presence of SPE/TRBE in kvm_host_data instead of vCPU 



Add flags to kvm_host_data to track if SPE/TRBE is present +
programmable on a per-CPU basis. Set the flags up at init rather than
vcpu_load() as the programmability of these buffers is unlikely to
change.

Reviewed-by: default avatarJames Clark <james.clark@linaro.org>
Tested-by: default avatarJames Clark <james.clark@linaro.org>
Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241219224116.3941496-4-oliver.upton@linux.dev


Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent 2417218f

arch/arm64/include/asm/kvm_host.h

+11 −8
Original line number Diff line number Diff line
@@ -610,6 +610,10 @@ struct cpu_sve_state { 
 * field.

 */

struct kvm_host_data {

#define KVM_HOST_DATA_FLAG_HAS_SPE	0

#define KVM_HOST_DATA_FLAG_HAS_TRBE	1

	unsigned long flags;



	struct kvm_cpu_context host_ctxt;



	/*
@@ -911,10 +915,6 @@ struct kvm_vcpu_arch { 
#define EXCEPT_AA64_EL2_SERR	__vcpu_except_flags(7)

/* Guest debug is live */

#define DEBUG_DIRTY		__vcpu_single_flag(iflags, BIT(4))

/* Save SPE context if active  */

#define DEBUG_STATE_SAVE_SPE	__vcpu_single_flag(iflags, BIT(5))

/* Save TRBE context if active  */

#define DEBUG_STATE_SAVE_TRBE	__vcpu_single_flag(iflags, BIT(6))



/* SVE enabled for host EL0 */

#define HOST_SVE_ENABLED	__vcpu_single_flag(sflags, BIT(0))
@@ -1310,6 +1310,13 @@ DECLARE_KVM_HYP_PER_CPU(struct kvm_host_data, kvm_host_data); 
	 &this_cpu_ptr_hyp_sym(kvm_host_data)->f)

#endif



#define host_data_test_flag(flag)					\

	(test_bit(KVM_HOST_DATA_FLAG_##flag, host_data_ptr(flags)))

#define host_data_set_flag(flag)					\

	set_bit(KVM_HOST_DATA_FLAG_##flag, host_data_ptr(flags))

#define host_data_clear_flag(flag)					\

	clear_bit(KVM_HOST_DATA_FLAG_##flag, host_data_ptr(flags))



/* Check whether the FP regs are owned by the guest */

static inline bool guest_owns_fp_regs(void)

{
@@ -1370,10 +1377,6 @@ static inline bool kvm_pmu_counter_deferred(struct perf_event_attr *attr) 
	return (!has_vhe() && attr->exclude_host);

}



/* Flags for host debug state */

void kvm_arch_vcpu_load_debug_state_flags(struct kvm_vcpu *vcpu);

void kvm_arch_vcpu_put_debug_state_flags(struct kvm_vcpu *vcpu);



#ifdef CONFIG_KVM

void kvm_set_pmu_events(u64 set, struct perf_event_attr *attr);

void kvm_clr_pmu_events(u64 clr);

arch/arm64/kvm/arm.c

+0 −3
Original line number Diff line number Diff line
@@ -617,15 +617,12 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) 


	vcpu_set_pauth_traps(vcpu);



	kvm_arch_vcpu_load_debug_state_flags(vcpu);



	if (!cpumask_test_cpu(cpu, vcpu->kvm->arch.supported_cpus))

		vcpu_set_on_unsupported_cpu(vcpu);

}



void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)

{

	kvm_arch_vcpu_put_debug_state_flags(vcpu);

	kvm_arch_vcpu_put_fp(vcpu);

	if (has_vhe())

		kvm_vcpu_put_vhe(vcpu);

arch/arm64/kvm/debug.c

+9 −27
Original line number Diff line number Diff line
@@ -294,40 +294,22 @@ void kvm_arm_clear_debug(struct kvm_vcpu *vcpu) 
	}

}



void kvm_arch_vcpu_load_debug_state_flags(struct kvm_vcpu *vcpu)

void kvm_init_host_debug_data(void)

{

	u64 dfr0;

	u64 dfr0 = read_sysreg(id_aa64dfr0_el1);



	if (cpuid_feature_extract_signed_field(dfr0, ID_AA64DFR0_EL1_PMUVer_SHIFT) > 0)

		*host_data_ptr(nr_event_counters) = FIELD_GET(ARMV8_PMU_PMCR_N,

							      read_sysreg(pmcr_el0));



	/* For VHE, there is nothing to do */

	if (has_vhe())

		return;



	dfr0 = read_sysreg(id_aa64dfr0_el1);

	/*

	 * If SPE is present on this CPU and is available at current EL,

	 * we may need to check if the host state needs to be saved.

	 */

	if (cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_PMSVer_SHIFT) &&

	    !(read_sysreg_s(SYS_PMBIDR_EL1) & BIT(PMBIDR_EL1_P_SHIFT)))

		vcpu_set_flag(vcpu, DEBUG_STATE_SAVE_SPE);

	    !(read_sysreg_s(SYS_PMBIDR_EL1) & PMBIDR_EL1_P))

		host_data_set_flag(HAS_SPE);



	/* Check if we have TRBE implemented and available at the host */

	if (cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_TraceBuffer_SHIFT) &&

	    !(read_sysreg_s(SYS_TRBIDR_EL1) & TRBIDR_EL1_P))

		vcpu_set_flag(vcpu, DEBUG_STATE_SAVE_TRBE);

}



void kvm_arch_vcpu_put_debug_state_flags(struct kvm_vcpu *vcpu)

{

	vcpu_clear_flag(vcpu, DEBUG_STATE_SAVE_SPE);

	vcpu_clear_flag(vcpu, DEBUG_STATE_SAVE_TRBE);

}



void kvm_init_host_debug_data(void)

{

	u64 dfr0 = read_sysreg(id_aa64dfr0_el1);



	if (cpuid_feature_extract_signed_field(dfr0, ID_AA64DFR0_EL1_PMUVer_SHIFT) > 0)

		*host_data_ptr(nr_event_counters) = FIELD_GET(ARMV8_PMU_PMCR_N,

							      read_sysreg(pmcr_el0));

		host_data_set_flag(HAS_TRBE);

}

arch/arm64/kvm/hyp/nvhe/debug-sr.c

+4 −4
Original line number Diff line number Diff line
@@ -82,10 +82,10 @@ static void __debug_restore_trace(u64 trfcr_el1) 
void __debug_save_host_buffers_nvhe(struct kvm_vcpu *vcpu)

{

	/* Disable and flush SPE data generation */

	if (vcpu_get_flag(vcpu, DEBUG_STATE_SAVE_SPE))

	if (host_data_test_flag(HAS_SPE))

		__debug_save_spe(host_data_ptr(host_debug_state.pmscr_el1));

	/* Disable and flush Self-Hosted Trace generation */

	if (vcpu_get_flag(vcpu, DEBUG_STATE_SAVE_TRBE))

	if (host_data_test_flag(HAS_TRBE))

		__debug_save_trace(host_data_ptr(host_debug_state.trfcr_el1));

}
@@ -96,9 +96,9 @@ void __debug_switch_to_guest(struct kvm_vcpu *vcpu) 


void __debug_restore_host_buffers_nvhe(struct kvm_vcpu *vcpu)

{

	if (vcpu_get_flag(vcpu, DEBUG_STATE_SAVE_SPE))

	if (host_data_test_flag(HAS_SPE))

		__debug_restore_spe(*host_data_ptr(host_debug_state.pmscr_el1));

	if (vcpu_get_flag(vcpu, DEBUG_STATE_SAVE_TRBE))

	if (host_data_test_flag(HAS_TRBE))

		__debug_restore_trace(*host_data_ptr(host_debug_state.trfcr_el1));

}