From e928e9cb3601ce240189bfea05b67ebd391c85ae Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Fri, 20 Mar 2015 20:39:41 +1100 Subject: 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 Signed-off-by: Paul Mackerras Signed-off-by: Alexander Graf --- arch/powerpc/include/asm/archrandom.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'arch/powerpc/include/asm/archrandom.h') diff --git a/arch/powerpc/include/asm/archrandom.h b/arch/powerpc/include/asm/archrandom.h index bde531103638..0cc6eedc4780 100644 --- a/arch/powerpc/include/asm/archrandom.h +++ b/arch/powerpc/include/asm/archrandom.h @@ -30,8 +30,6 @@ static inline int arch_has_random(void) return !!ppc_md.get_random_long; } -int powernv_get_random_long(unsigned long *v); - static inline int arch_get_random_seed_long(unsigned long *v) { return 0; @@ -47,4 +45,13 @@ static inline int arch_has_random_seed(void) #endif /* CONFIG_ARCH_RANDOM */ +#ifdef CONFIG_PPC_POWERNV +int powernv_hwrng_present(void); +int powernv_get_random_long(unsigned long *v); +int powernv_get_random_real_mode(unsigned long *v); +#else +static inline int powernv_hwrng_present(void) { return 0; } +static inline int powernv_get_random_real_mode(unsigned long *v) { return 0; } +#endif + #endif /* _ASM_POWERPC_ARCHRANDOM_H */ -- cgit v1.2.3