On Thu, 2024-10-10 at 21:53 +0000, Edgecombe, Rick P wrote: > On Thu, 2024-10-10 at 10:33 -0700, Sean Christopherson wrote: > > > > > > 1st: "fault->is_private != kvm_mem_is_private(kvm, fault->gfn)" is found. > > > 2nd-6th: try_cmpxchg64() fails on each level SPTEs (5 levels in total) > > Isn't there a more general scenario: > > vcpu0 vcpu1 > 1. Freezes PTE > 2. External op to do the SEAMCALL > 3. Faults same PTE, hits frozen PTE > 4. Retries N times, triggers zero-step > 5. Finally finishes external op > > Am I missing something? I must be missing something. I thought KVM is going to retry internally for step 4 (retries N times) because it sees the frozen PTE, but will never go back to guest after the fault is resolved? How can step 4 triggers zero-step?
