From e3c1c0cae31ec9ebfdffeaa2c86ddeba6cf5c74c Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Fri, 9 Jun 2023 19:00:45 +0000 Subject: [PATCH] KVM: arm64: Relax invariance of KVM_ARM_VCPU_POWER_OFF Allow the value of KVM_ARM_VCPU_POWER_OFF to differ between calls to KVM_ARM_VCPU_INIT. Userspace can already change the state of the vCPU through the KVM_SET_MP_STATE ioctl, so making the bit invariant seems needlessly restrictive. Link: https://lore.kernel.org/r/20230609190054.1542113-3-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/arm.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index d529805..a9c18f4 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -1236,8 +1236,19 @@ static int kvm_vcpu_set_target(struct kvm_vcpu *vcpu, static int kvm_arch_vcpu_ioctl_vcpu_init(struct kvm_vcpu *vcpu, struct kvm_vcpu_init *init) { + bool power_off = false; int ret; + /* + * Treat the power-off vCPU feature as ephemeral. Clear the bit to avoid + * reflecting it in the finalized feature set, thus limiting its scope + * to a single KVM_ARM_VCPU_INIT call. + */ + if (init->features[0] & KVM_ARM_VCPU_POWER_OFF) { + init->features[0] &= ~KVM_ARM_VCPU_POWER_OFF; + power_off = true; + } + ret = kvm_vcpu_set_target(vcpu, init); if (ret) return ret; @@ -1266,7 +1277,7 @@ static int kvm_arch_vcpu_ioctl_vcpu_init(struct kvm_vcpu *vcpu, */ spin_lock(&vcpu->arch.mp_state_lock); - if (test_bit(KVM_ARM_VCPU_POWER_OFF, vcpu->arch.features)) + if (power_off) __kvm_arm_vcpu_power_off(vcpu); else WRITE_ONCE(vcpu->arch.mp_state.mp_state, KVM_MP_STATE_RUNNABLE); -- 2.7.4