6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sebastian Ene <sebastianene@xxxxxxxxxx> commit 10c02aad111df02088d1a81792a709f6a7eca6cc upstream. The rule inside kvm enforces that the vcpu->mutex is taken *inside* kvm->lock. The rule is violated by the pkvm_create_hyp_vm() which acquires the kvm->lock while already holding the vcpu->mutex lock from kvm_vcpu_ioctl(). Avoid the circular locking dependency altogether by protecting the hyp vm handle with the config_lock, much like we already do for other forms of VM-scoped data. Signed-off-by: Sebastian Ene <sebastianene@xxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Reviewed-by: Oliver Upton <oliver.upton@xxxxxxxxx> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx> Link: https://lore.kernel.org/r/20240124091027.1477174-2-sebastianene@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/arm64/kvm/pkvm.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) --- a/arch/arm64/kvm/pkvm.c +++ b/arch/arm64/kvm/pkvm.c @@ -101,6 +101,17 @@ void __init kvm_hyp_reserve(void) hyp_mem_base); } +static void __pkvm_destroy_hyp_vm(struct kvm *host_kvm) +{ + if (host_kvm->arch.pkvm.handle) { + WARN_ON(kvm_call_hyp_nvhe(__pkvm_teardown_vm, + host_kvm->arch.pkvm.handle)); + } + + host_kvm->arch.pkvm.handle = 0; + free_hyp_memcache(&host_kvm->arch.pkvm.teardown_mc); +} + /* * Allocates and donates memory for hypervisor VM structs at EL2. * @@ -181,7 +192,7 @@ static int __pkvm_create_hyp_vm(struct k return 0; destroy_vm: - pkvm_destroy_hyp_vm(host_kvm); + __pkvm_destroy_hyp_vm(host_kvm); return ret; free_vm: free_pages_exact(hyp_vm, hyp_vm_sz); @@ -194,23 +205,19 @@ int pkvm_create_hyp_vm(struct kvm *host_ { int ret = 0; - mutex_lock(&host_kvm->lock); + mutex_lock(&host_kvm->arch.config_lock); if (!host_kvm->arch.pkvm.handle) ret = __pkvm_create_hyp_vm(host_kvm); - mutex_unlock(&host_kvm->lock); + mutex_unlock(&host_kvm->arch.config_lock); return ret; } void pkvm_destroy_hyp_vm(struct kvm *host_kvm) { - if (host_kvm->arch.pkvm.handle) { - WARN_ON(kvm_call_hyp_nvhe(__pkvm_teardown_vm, - host_kvm->arch.pkvm.handle)); - } - - host_kvm->arch.pkvm.handle = 0; - free_hyp_memcache(&host_kvm->arch.pkvm.teardown_mc); + mutex_lock(&host_kvm->arch.config_lock); + __pkvm_destroy_hyp_vm(host_kvm); + mutex_unlock(&host_kvm->arch.config_lock); } int pkvm_init_host_vm(struct kvm *host_kvm)
