Not really, no. Sent from my tablet, pardon any formatting problems.
> On Sep 22, 2014, at 06:31, Christopher Covington <c...@codeaurora.org> wrote: > >> On 09/19/2014 05:46 PM, H. Peter Anvin wrote: >> On 09/19/2014 01:46 PM, Andy Lutomirski wrote: >>>> >>>> However, it sounds to me that at least for KVM, it is very easy just to >>>> emulate the RDRAND instruction. The hypervisor would report to the guest >>>> that RDRAND is supported in CPUID and the emulate the instruction when >>>> guest executes it. KVM already traps guest #UD (which would occur if >>>> RDRAND executed while it is not supported) - so this scheme wouldn’t >>>> introduce additional overhead over RDMSR. >>> >>> Because then guest user code will think that rdrand is there and will >>> try to use it, resulting in abysmal performance. >> >> Yes, the presence of RDRAND implies a cheap and inexhaustible entropy >> source. > > A guest kernel couldn't make it look like RDRAND is not present to guest > userspace? > > Christopher > > -- > Employee of Qualcomm Innovation Center, Inc. > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, > hosted by the Linux Foundation. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
