Messages in this thread | | | Subject | Re: [PATCH Part2 v5 34/45] KVM: SVM: Do not use long-lived GHCB map while setting scratch area | From | Brijesh Singh <> | Date | Fri, 15 Oct 2021 11:11:19 -0500 |
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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 ?
-Brijesh
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