On Fri, Oct 15, 2021, Brijesh Singh wrote: > > On 10/13/21 2:20 PM, Sean Christopherson wrote: > > On Fri, Aug 20, 2021, Brijesh Singh wrote: > >> The setup_vmgexit_scratch() function may rely on a long-lived GHCB > >> mapping if the GHCB shared buffer area was used for the scratch area. > >> In preparation for eliminating the long-lived GHCB mapping, always > >> allocate a buffer for the scratch area so it can be accessed without > >> the GHCB mapping. > > Would it make sense to post this patch and the next (Remove the long-lived GHCB > > host map) in a separate mini-series? It's needed for SNP, but AFAICT there's > > nothing that depends on SNP. Getting this merged ahead of time would reduce the > > size of the SNP series by a smidge. > > While testing with random configs, I am seeing some might_sleep() warns. > This is happening mainly because during the vmrun the GHCB is accessed > with preempt disabled. The kvm_vcpu_map() -> kmap() reports the warning. > I am leaning towards creating a cache on the vmgexit and use that cache > instead of the doing a kmap() on every access. Does that sound okay to you ? Since SEV is 64-bit only, it should be ok to add a kvm_vcpu_map_atomic() variant.
