On 25/05/2018 21:51, Stefano Stabellini wrote: > On Wed, 23 May 2018, Julien Grall wrote: >> Hi, >> >> On 05/23/2018 10:57 PM, Stefano Stabellini wrote: >>> On Tue, 22 May 2018, Julien Grall wrote: >>>> As for Spectre variant-2, we rely on SMCCC 1.1 to provide the discovery >>>> mechanism for detecting the SSBD mitigation. >>>> >>>> A new capability is also allocated for that purpose, and a config >>>> option. >>>> >>>> This is part of XSA-263. >>>> >>>> Signed-off-by: Julien Grall <julien.gr...@arm.com> >>>> --- >>>> xen/arch/arm/Kconfig | 10 ++++++++++ >>>> xen/arch/arm/cpuerrata.c | 39 >>>> +++++++++++++++++++++++++++++++++++++++ >>>> xen/include/asm-arm/cpuerrata.h | 21 +++++++++++++++++++++ >>>> xen/include/asm-arm/cpufeature.h | 3 ++- >>>> xen/include/asm-arm/smccc.h | 6 ++++++ >>>> 5 files changed, 78 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig >>>> index 8174c0c635..0e2d027060 100644 >>>> --- a/xen/arch/arm/Kconfig >>>> +++ b/xen/arch/arm/Kconfig >>>> @@ -73,6 +73,16 @@ config SBSA_VUART_CONSOLE >>>> Allows a guest to use SBSA Generic UART as a console. The >>>> SBSA Generic UART implements a subset of ARM PL011 UART. >>>> +config ARM_SSBD >>>> + bool "Speculative Store Bypass Disable" if EXPERT = "y" >>>> + depends on HAS_ALTERNATIVE >>>> + default y >>>> + help >>>> + This enables mitigation of bypassing of previous stores by >>>> speculative >>>> + loads. >>> I would add a reference to spectre v4. What do you think of: >>> >>> This enables the mitigation of Spectre v4 attacks based on bypassing >>> of previous memory stores by speculative loads. >> Well, the real name is SSBD (Speculative Store Bypass Disable). AFAIK, >> Spectre >> only refers to variant 1 and 2 so far. This one has no fancy name and the >> specifications is using SSBD. > Googling for Spectre Variant 4 returns twice as many results as Googling > for Speculative Store Bypass Disable. It doesn't matter what is the > official name for the security issue, I think we need to include a > reference to the most common name for it.
"Speculative Store Bypass" is the agreed vendor-neutral name for the issue. This is why all the mitigation is SSBD, where the D on the end is Disable. Google SP4 is a common name (but only covers one reporter of the issue), whereas Spectre has nothing to do with this issue, and is definitely wrong to use. If in doubt, use SSB(D). ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
