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KVM: arm64: Enforce reserved bits for PSCI target affinities

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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: Oliver Upton <oupton@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210818202133.1106786-4-oupton@google.com
This commit is contained in:
Oliver Upton 2021-08-18 20:21:32 +00:00 committed by Marc Zyngier
parent 6826c6849b
commit e10ecb4d6c
1 changed files with 12 additions and 3 deletions
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15
arch/arm64/kvm/psci.c
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@ -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)