Re: [PATCH 3/7] target/i386: TCG supports RDSEED

[Richard Henderson]

On 6/18/23 23:51, Paolo Bonzini wrote:
> TCG implements RDSEED, and in fact uses qcrypto_random_bytes which is
> secure enough to match hardware behavior.  Expose it to guests.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>   target/i386/cpu.c | 5 ++---
>   1 file changed, 2 insertions(+), 3 deletions(-)

TCG protects both RDRAND and RDSEED with CPUID_EXT_RDRAND.
I guess we should use CPUID_7_0_EBX_RDSEED for RDSEED?


r~

> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index ff3dcd02dcb..fc4246223d4 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -657,11 +657,10 @@ void x86_cpu_vendor_words2str(char *dst, uint32_t vendor1,
>             CPUID_7_0_EBX_BMI1 | CPUID_7_0_EBX_BMI2 | CPUID_7_0_EBX_ADX | \
>             CPUID_7_0_EBX_PCOMMIT | CPUID_7_0_EBX_CLFLUSHOPT |            \
>             CPUID_7_0_EBX_CLWB | CPUID_7_0_EBX_MPX | CPUID_7_0_EBX_FSGSBASE | \
> -          CPUID_7_0_EBX_ERMS | CPUID_7_0_EBX_AVX2)
> +          CPUID_7_0_EBX_ERMS | CPUID_7_0_EBX_AVX2 | CPUID_7_0_EBX_RDSEED)
>             /* missing:
>             CPUID_7_0_EBX_HLE
> -          CPUID_7_0_EBX_INVPCID, CPUID_7_0_EBX_RTM,
> -          CPUID_7_0_EBX_RDSEED */
> +          CPUID_7_0_EBX_INVPCID, CPUID_7_0_EBX_RTM */
>   #define TCG_7_0_ECX_FEATURES (CPUID_7_0_ECX_UMIP | CPUID_7_0_ECX_PKU | \
>             /* CPUID_7_0_ECX_OSPKE is dynamic */ \
>             CPUID_7_0_ECX_LA57 | CPUID_7_0_ECX_PKS | CPUID_7_0_ECX_VAES)