Files
linux/Documentation
Michael Ellerman e928e9cb36 KVM: PPC: Book3S HV: Add fast real-mode H_RANDOM implementation.
Some PowerNV systems include a hardware random-number generator.
This HWRNG is present on POWER7+ and POWER8 chips and is capable of
generating one 64-bit random number every microsecond.  The random
numbers are produced by sampling a set of 64 unstable high-frequency
oscillators and are almost completely entropic.

PAPR defines an H_RANDOM hypercall which guests can use to obtain one
64-bit random sample from the HWRNG.  This adds a real-mode
implementation of the H_RANDOM hypercall.  This hypercall was
implemented in real mode because the latency of reading the HWRNG is
generally small compared to the latency of a guest exit and entry for
all the threads in the same virtual core.

Userspace can detect the presence of the HWRNG and the H_RANDOM
implementation by querying the KVM_CAP_PPC_HWRNG capability.  The
H_RANDOM hypercall implementation will only be invoked when the guest
does an H_RANDOM hypercall if userspace first enables the in-kernel
H_RANDOM implementation using the KVM_CAP_PPC_ENABLE_HCALL capability.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
2015-04-21 15:21:29 +02:00
..
2014-10-09 22:26:02 -04:00
2014-05-05 15:32:05 +02:00
2014-02-28 15:12:08 -08:00
2014-08-25 03:28:09 -05:00
2014-02-10 16:01:40 -08:00
2014-12-10 17:41:10 -08:00
2013-01-10 01:27:46 +01:00
2014-06-19 17:45:14 -07:00
2015-02-02 14:23:42 -08:00
2015-02-27 11:44:24 -08:00
2014-05-05 15:32:05 +02:00
2013-12-02 14:48:28 +01:00
2014-03-21 13:16:58 +01:00
2014-12-08 09:07:11 -05:00
2013-12-02 14:45:19 +01:00
2014-11-21 19:48:50 +05:30
2014-05-05 15:32:05 +02:00
2014-05-05 15:32:05 +02:00
2014-09-23 23:44:16 -07:00