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KVM: arm64: Relax invariance of KVM_ARM_VCPU_POWER_OFF

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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 <oliver.upton@linux.dev>
This commit is contained in:
Oliver Upton 2023-06-09 19:00:45 +00:00
parent a7a2c72ae0
commit e3c1c0cae3
1 changed files with 12 additions and 1 deletions
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13
arch/arm64/kvm/arm.c
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@ -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);