diff options
| author | Oliver Upton <oliver.upton@linux.dev> | 2023-03-27 16:47:46 +0000 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2023-03-29 14:08:31 +0100 |
| commit | 4bba7f7def6f278266dadf845da472cfbfed784e (patch) | |
| tree | 67890de6d6e2ead26bc81bdd90007db0a120ac33 /arch/arm64/kvm/guest.c | |
| parent | c43120afb5c66a3465c7468f5cf9806a26484cde (diff) | |
KVM: arm64: Use config_lock to protect data ordered against KVM_RUN
There are various bits of VM-scoped data that can only be configured
before the first call to KVM_RUN, such as the hypercall bitmaps and
the PMU. As these fields are protected by the kvm->lock and accessed
while holding vcpu->mutex, this is yet another example of lock
inversion.
Change out the kvm->lock for kvm->arch.config_lock in all of these
instances. Opportunistically simplify the locking mechanics of the
PMU configuration by holding the config_lock for the entirety of
kvm_arm_pmu_v3_set_attr().
Note that this also addresses a couple of bugs. There is an unguarded
read of the PMU version in KVM_ARM_VCPU_PMU_V3_FILTER which could race
with KVM_ARM_VCPU_PMU_V3_SET_PMU. Additionally, until now writes to the
per-vCPU vPMU irq were not serialized VM-wide, meaning concurrent calls
to KVM_ARM_VCPU_PMU_V3_IRQ could lead to a false positive in
pmu_irq_is_valid().
Cc: stable@vger.kernel.org
Tested-by: Jeremy Linton <jeremy.linton@arm.com>
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230327164747.2466958-4-oliver.upton@linux.dev
Diffstat (limited to 'arch/arm64/kvm/guest.c')
| -rw-r--r-- | arch/arm64/kvm/guest.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c index 07444fa22888..481c79cf22cd 100644 --- a/arch/arm64/kvm/guest.c +++ b/arch/arm64/kvm/guest.c @@ -957,7 +957,9 @@ int kvm_arm_vcpu_arch_set_attr(struct kvm_vcpu *vcpu, switch (attr->group) { case KVM_ARM_VCPU_PMU_V3_CTRL: + mutex_lock(&vcpu->kvm->arch.config_lock); ret = kvm_arm_pmu_v3_set_attr(vcpu, attr); + mutex_unlock(&vcpu->kvm->arch.config_lock); break; case KVM_ARM_VCPU_TIMER_CTRL: ret = kvm_arm_timer_set_attr(vcpu, attr); |