Commit e10ecb4d authored by Oliver Upton's avatar Oliver Upton Committed by Marc Zyngier
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KVM: arm64: Enforce reserved bits for PSCI target affinities 



According to the PSCI specification, ARM DEN 0022D, 5.1.4 "CPU_ON", the
CPU_ON function takes a target_cpu argument that is bit-compatible with
the affinity fields in MPIDR_EL1. All other bits in the argument are
RES0. Note that the same constraints apply to the target_affinity
argument for the AFFINITY_INFO call.

Enforce the spec by returning INVALID_PARAMS if a guest incorrectly sets
a RES0 bit.

Signed-off-by: default avatarOliver Upton <oupton@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210818202133.1106786-4-oupton@google.com
parent 6826c684

arch/arm64/kvm/psci.c

+12 −3
Original line number Diff line number Diff line
@@ -59,6 +59,12 @@ static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu) 
	kvm_vcpu_kick(vcpu);

}



static inline bool kvm_psci_valid_affinity(struct kvm_vcpu *vcpu,

					   unsigned long affinity)

{

	return !(affinity & ~MPIDR_HWID_BITMASK);

}



static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)

{

	struct vcpu_reset_state *reset_state;
@@ -66,9 +72,9 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu) 
	struct kvm_vcpu *vcpu = NULL;

	unsigned long cpu_id;



	cpu_id = smccc_get_arg1(source_vcpu) & MPIDR_HWID_BITMASK;

	if (vcpu_mode_is_32bit(source_vcpu))

		cpu_id &= ~((u32) 0);

	cpu_id = smccc_get_arg1(source_vcpu);

	if (!kvm_psci_valid_affinity(source_vcpu, cpu_id))

		return PSCI_RET_INVALID_PARAMS;



	vcpu = kvm_mpidr_to_vcpu(kvm, cpu_id);
@@ -126,6 +132,9 @@ static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu) 
	target_affinity = smccc_get_arg1(vcpu);

	lowest_affinity_level = smccc_get_arg2(vcpu);



	if (!kvm_psci_valid_affinity(vcpu, target_affinity))

		return PSCI_RET_INVALID_PARAMS;



	/* Determine target affinity mask */

	target_affinity_mask = psci_affinity_mask(lowest_affinity_level);

	if (!target_affinity_mask)