diff options
| author | Yong-Xuan Wang <yongxuan.wang@sifive.com> | 2024-04-17 15:45:25 +0800 |
|---|---|---|
| committer | Anup Patel <anup@brainfault.org> | 2024-04-22 10:37:11 +0530 |
| commit | 2121cadec45aaf61fa45b3aa3d99723ed4e6683a (patch) | |
| tree | 4e2988e18b8011af58bca07e987a3c48d73bea6b /arch/riscv/kvm/vcpu_sbi.c | |
| parent | f1c48c1ec73538a8e49695445a0fbc52156aac42 (diff) | |
RISCV: KVM: Introduce mp_state_lock to avoid lock inversion
Documentation/virt/kvm/locking.rst advises that kvm->lock should be
acquired outside vcpu->mutex and kvm->srcu. However, when KVM/RISC-V
handling SBI_EXT_HSM_HART_START, the lock ordering is vcpu->mutex,
kvm->srcu then kvm->lock.
Although the lockdep checking no longer complains about this after commit
f0f44752f5f6 ("rcu: Annotate SRCU's update-side lockdep dependencies"),
it's necessary to replace kvm->lock with a new dedicated lock to ensure
only one hart can execute the SBI_EXT_HSM_HART_START call for the target
hart simultaneously.
Additionally, this patch also rename "power_off" to "mp_state" with two
possible values. The vcpu->mp_state_lock also protects the access of
vcpu->mp_state.
Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20240417074528.16506-2-yongxuan.wang@sifive.com
Signed-off-by: Anup Patel <anup@brainfault.org>
Diffstat (limited to 'arch/riscv/kvm/vcpu_sbi.c')
| -rw-r--r-- | arch/riscv/kvm/vcpu_sbi.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c index 72a2ffb8dcd1..62f409d4176e 100644 --- a/arch/riscv/kvm/vcpu_sbi.c +++ b/arch/riscv/kvm/vcpu_sbi.c @@ -138,8 +138,11 @@ void kvm_riscv_vcpu_sbi_system_reset(struct kvm_vcpu *vcpu, unsigned long i; struct kvm_vcpu *tmp; - kvm_for_each_vcpu(i, tmp, vcpu->kvm) - tmp->arch.power_off = true; + kvm_for_each_vcpu(i, tmp, vcpu->kvm) { + spin_lock(&vcpu->arch.mp_state_lock); + WRITE_ONCE(tmp->arch.mp_state.mp_state, KVM_MP_STATE_STOPPED); + spin_unlock(&vcpu->arch.mp_state_lock); + } kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP); memset(&run->system_event, 0, sizeof(run->system_event)); |