diff options
| author | Peng Hao <flyingpeng@tencent.com> | 2022-11-08 11:50:54 +0800 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2022-11-30 16:00:02 -0800 |
| commit | 4265df667bbdc71c640e43c905bd9aeeead92365 (patch) | |
| tree | ba2beb9e7e3c566280e874252b54f33f695b5a79 /arch/x86/kvm | |
| parent | eb3992e833d3a17f9b0a3e0371d0b1d3d566f740 (diff) | |
| download | linux-4265df667bbdc71c640e43c905bd9aeeead92365.tar.bz2 | |
KVM: x86: Keep the lock order consistent between SRCU and gpc spinlock
Acquire SRCU before taking the gpc spinlock in wait_pending_event() so as
to be consistent with all other functions that acquire both locks. It's
not illegal to acquire SRCU inside a spinlock, nor is there deadlock
potential, but in general it's preferable to order locks from least
restrictive to most restrictive, e.g. if wait_pending_event() needed to
sleep for whatever reason, it could do so while holding SRCU, but would
need to drop the spinlock.
Signed-off-by: Peng Hao <flyingpeng@tencent.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/CAPm50a++Cb=QfnjMZ2EnCj-Sb9Y4UM-=uOEtHAcjnNLCAAf-dQ@mail.gmail.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86/kvm')
| -rw-r--r-- | arch/x86/kvm/xen.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c index 9187d024d006..2f21fa5ee7de 100644 --- a/arch/x86/kvm/xen.c +++ b/arch/x86/kvm/xen.c @@ -1165,8 +1165,8 @@ static bool wait_pending_event(struct kvm_vcpu *vcpu, int nr_ports, bool ret = true; int idx, i; - read_lock_irqsave(&gpc->lock, flags); idx = srcu_read_lock(&kvm->srcu); + read_lock_irqsave(&gpc->lock, flags); if (!kvm_gpc_check(kvm, gpc, gpc->gpa, PAGE_SIZE)) goto out_rcu; @@ -1187,8 +1187,8 @@ static bool wait_pending_event(struct kvm_vcpu *vcpu, int nr_ports, } out_rcu: - srcu_read_unlock(&kvm->srcu, idx); read_unlock_irqrestore(&gpc->lock, flags); + srcu_read_unlock(&kvm->srcu, idx); return ret; } |