mirror of
https://github.com/torvalds/linux.git
synced 2024-12-23 19:31:53 +00:00
e928e9cb36
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> |
||
|---|---|---|
| .. | ||
| devices | ||
| 00-INDEX | ||
| api.txt | ||
| cpuid.txt | ||
| hypercalls.txt | ||
| locking.txt | ||
| mmu.txt | ||
| msr.txt | ||
| nested-vmx.txt | ||
| ppc-pv.txt | ||
| review-checklist.txt | ||
| s390-diag.txt | ||
| timekeeping.txt | ||