> -----Original Message----- > From: H. Peter Anvin [mailto:hpa@xxxxxxxxx] > Sent: Tuesday, July 23, 2013 10:48 AM > To: KY Srinivasan > Cc: Jason Wang; tglx@xxxxxxxxxxxxx; mingo@xxxxxxxxxx; x86@xxxxxxxxxx; > gleb@xxxxxxxxxx; pbonzini@xxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx > Subject: Re: [PATCH 4/4] x86: properly handle kvm emulation of hyperv > > On 07/23/2013 06:55 AM, KY Srinivasan wrote: > > > > This strategy of hypervisor detection based on some detection order IMHO is > not > > a robust detection strategy. The current scheme works since the only > hypervisor emulated > > (by other hypervisors happens to be Hyper-V). What if this were to change. > > > > One strategy would be to pick the *last* one in the CPUID list, since > the ones before it are logically the one(s) being emulated... Is it always possible to guarantee this ordering. As a hypothetical, what if hypervisor A emulates Hypervisor B and Hypervisor B emulates Hypervisor A. In this case we cannot have any "order" based detection that can yield "correct" detection. I define "correctness" as follows: If a guest can run on both the hypervisors, the guest should detect the true native Hypervisor. Regards, K. Y -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
