Commit 5d81f7dc authored by Marc Zyngier's avatar Marc Zyngier Committed by Catalin Marinas
Browse files

arm64: KVM: Add ARCH_WORKAROUND_2 discovery through ARCH_FEATURES_FUNC_ID 



Now that all our infrastructure is in place, let's expose the
availability of ARCH_WORKAROUND_2 to guests. We take this opportunity
to tidy up a couple of SMCCC constants.

Acked-by: default avatarChristoffer Dall <christoffer.dall@arm.com>
Reviewed-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent b4f18c06

arch/arm/include/asm/kvm_host.h

+12 −0
Original line number Diff line number Diff line
@@ -315,6 +315,18 @@ static inline bool kvm_arm_harden_branch_predictor(void) 
	return false;

}



#define KVM_SSBD_UNKNOWN		-1

#define KVM_SSBD_FORCE_DISABLE		0

#define KVM_SSBD_KERNEL		1

#define KVM_SSBD_FORCE_ENABLE		2

#define KVM_SSBD_MITIGATED		3



static inline int kvm_arm_have_ssbd(void)

{

	/* No way to detect it yet, pretend it is not there. */

	return KVM_SSBD_UNKNOWN;

}



static inline void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu) {}

static inline void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu) {}

arch/arm64/include/asm/kvm_host.h

+23 −0
Original line number Diff line number Diff line
@@ -455,6 +455,29 @@ static inline bool kvm_arm_harden_branch_predictor(void) 
	return cpus_have_const_cap(ARM64_HARDEN_BRANCH_PREDICTOR);

}



#define KVM_SSBD_UNKNOWN		-1

#define KVM_SSBD_FORCE_DISABLE		0

#define KVM_SSBD_KERNEL		1

#define KVM_SSBD_FORCE_ENABLE		2

#define KVM_SSBD_MITIGATED		3



static inline int kvm_arm_have_ssbd(void)

{

	switch (arm64_get_ssbd_state()) {

	case ARM64_SSBD_FORCE_DISABLE:

		return KVM_SSBD_FORCE_DISABLE;

	case ARM64_SSBD_KERNEL:

		return KVM_SSBD_KERNEL;

	case ARM64_SSBD_FORCE_ENABLE:

		return KVM_SSBD_FORCE_ENABLE;

	case ARM64_SSBD_MITIGATED:

		return KVM_SSBD_MITIGATED;

	case ARM64_SSBD_UNKNOWN:

	default:

		return KVM_SSBD_UNKNOWN;

	}

}



void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu);

void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu);

arch/arm64/kvm/reset.c

+4 −0
Original line number Diff line number Diff line
@@ -122,6 +122,10 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu) 
	/* Reset PMU */

	kvm_pmu_vcpu_reset(vcpu);



	/* Default workaround setup is enabled (if supported) */

	if (kvm_arm_have_ssbd() == KVM_SSBD_KERNEL)

		vcpu->arch.workaround_flags |= VCPU_WORKAROUND_2_FLAG;



	/* Reset timer */

	return kvm_timer_vcpu_reset(vcpu);

}

virt/kvm/arm/psci.c

+16 −2
Original line number Diff line number Diff line
@@ -405,7 +405,7 @@ static int kvm_psci_call(struct kvm_vcpu *vcpu) 
int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)

{

	u32 func_id = smccc_get_function(vcpu);

	u32 val = PSCI_RET_NOT_SUPPORTED;

	u32 val = SMCCC_RET_NOT_SUPPORTED;

	u32 feature;



	switch (func_id) {
@@ -417,7 +417,21 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) 
		switch(feature) {

		case ARM_SMCCC_ARCH_WORKAROUND_1:

			if (kvm_arm_harden_branch_predictor())

				val = 0;

				val = SMCCC_RET_SUCCESS;

			break;

		case ARM_SMCCC_ARCH_WORKAROUND_2:

			switch (kvm_arm_have_ssbd()) {

			case KVM_SSBD_FORCE_DISABLE:

			case KVM_SSBD_UNKNOWN:

				break;

			case KVM_SSBD_KERNEL:

				val = SMCCC_RET_SUCCESS;

				break;

			case KVM_SSBD_FORCE_ENABLE:

			case KVM_SSBD_MITIGATED:

				val = SMCCC_RET_NOT_REQUIRED;

				break;

			}

			break;

		}

		break;

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