On Tue, Oct 01, 2013 at 07:23:20PM +1000, Paul Mackerras wrote: > On Tue, Oct 01, 2013 at 11:39:08AM +0300, Gleb Natapov wrote: > > On Tue, Oct 01, 2013 at 06:34:26PM +1000, Michael Ellerman wrote: > > > On Thu, Sep 26, 2013 at 11:06:59AM +0200, Paolo Bonzini wrote: > > > > Il 26/09/2013 08:31, Michael Ellerman ha scritto: > > > > > Some powernv systems include a hwrng. Guests can access it via the > > > > > H_RANDOM hcall. > > > > > > > > Is there any reason to do this in the kernel? > > > > > > It's less code, and it's faster :) > > > > > > > It does not have to be a particularly fast path; > > > > > > Sure, but do we have to make it slow on purpose? > > > > > We do not put non performance critical devices into the kernel. > > It's not a device, it's a single hypercall, specified by PAPR, which > is the moral equivalent of x86's RDRAND. > OK. A couple of general questions. How guest knows when this hypercall is available? Is QEMU enable it when KVM_CAP_PPC_HWRNG is available (I haven't seen userspace patch that uses KVM_CAP_PPC_HWRNG)? What about QEMU TCG does it implement this hypercall or it emulates hwrng directly? -- Gleb. -- 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
