On Wed, Jun 10, 2020 at 07:55:31PM +0200, Vitaly Kuznetsov wrote: > schedule_work() returns 'false' only when the work is already on the queue > and this can't happen as kvm_setup_async_pf() always allocates a new one. > Also, to avoid potential race, it makes sense to to schedule_work() at the > very end after we've added it to the queue. > > While on it, do some minor cleanup. gfn_to_pfn_async() mentioned in a > comment does not currently exist and, moreover, we can check > kvm_is_error_hva() at the very beginning, before we try to allocate work so > 'retry_sync' label can go away completely. > > Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> > --- > virt/kvm/async_pf.c | 19 ++++++------------- > 1 file changed, 6 insertions(+), 13 deletions(-) > > diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c > index f1e07fae84e9..ba080088da76 100644 > --- a/virt/kvm/async_pf.c > +++ b/virt/kvm/async_pf.c > @@ -164,7 +164,9 @@ int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, > if (vcpu->async_pf.queued >= ASYNC_PF_PER_VCPU) > return 0; > > - /* setup delayed work */ > + /* Arch specific code should not do async PF in this case */ > + if (unlikely(kvm_is_error_hva(hva))) This feels like it should be changed to a WARN_ON_ONCE in a follow-up. With the WARN, the comment could probably be dropped. I'd also be in favor of changing the return type to a boolean. I think you alluded to it earlier, the current semantics are quite confusing as they invert the normal "return 0 on success". For this patch: Reviewed-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
