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KVM: arm64: Fix circular locking dependency 

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@google.com>
Cc: stable@vger.kernel.org
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240124091027.1477174-2-sebastianene@google.com
This commit is contained in:
Sebastian Ene 2024-01-24 09:10:28 +00:00 committed by Marc Zyngier
parent 6613476e22
commit 10c02aad11
1 changed files with 17 additions and 10 deletions
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27
arch/arm64/kvm/pkvm.c
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@ -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 kvm *host_kvm)
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_kvm)
{
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)