Re: [PATCH 2/4] KVM: nSVM: propagate the NPF EXITINFO to the guest

From: Paolo Bonzini
Date: Tue Sep 02 2014 - 13:01:31 EST


Il 02/09/2014 18:46, Paolo Bonzini ha scritto:
>> > How about an io-port emulated on
>> > L1 but passed through to L2 by the nested hypervisor. On emulation of
>> > INS or OUTS, KVM would need to read/write to an L2 address space,
> It would need to read/write to *L1* (that's where the VMCB's IOIO map
> lies), which could result into a regular page fault injected into L1.

Nevermind, the VMCB's IO bitmap is a guest physical address. I see what
you mean now. nested_svm_intercept_ioio would return NESTED_EXIT_HOST
and proceed to emulate the read/write. This could indeed cause a NPF.
For now I'll remove the WARN_ON.

Paolo
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