diff options
author | Oliver Upton <oliver.upton@linux.dev> | 2023-03-27 19:47:46 +0300 |
---|---|---|
committer | Marc Zyngier <maz@kernel.org> | 2023-03-29 16:08:31 +0300 |
commit | 4bba7f7def6f278266dadf845da472cfbfed784e (patch) | |
tree | 67890de6d6e2ead26bc81bdd90007db0a120ac33 /arch/arm64/kvm/hypercalls.c | |
parent | c43120afb5c66a3465c7468f5cf9806a26484cde (diff) | |
download | linux-4bba7f7def6f278266dadf845da472cfbfed784e.tar.xz |
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/hypercalls.c')
-rw-r--r-- | arch/arm64/kvm/hypercalls.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c index 5da884e11337..fbdbf4257f76 100644 --- a/arch/arm64/kvm/hypercalls.c +++ b/arch/arm64/kvm/hypercalls.c @@ -377,7 +377,7 @@ static int kvm_arm_set_fw_reg_bmap(struct kvm_vcpu *vcpu, u64 reg_id, u64 val) if (val & ~fw_reg_features) return -EINVAL; - mutex_lock(&kvm->lock); + mutex_lock(&kvm->arch.config_lock); if (test_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &kvm->arch.flags) && val != *fw_reg_bmap) { @@ -387,7 +387,7 @@ static int kvm_arm_set_fw_reg_bmap(struct kvm_vcpu *vcpu, u64 reg_id, u64 val) WRITE_ONCE(*fw_reg_bmap, val); out: - mutex_unlock(&kvm->lock); + mutex_unlock(&kvm->arch.config_lock); return ret; } |