Messages in this thread | | | Subject | Re: [PATCH v7 9/10] KVM: arm64: docs: document KVM support of pointer authentication | From | Amit Daniel Kachhap <> | Date | Thu, 28 Mar 2019 15:43:07 +0530 |
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Hi Dave,
On 3/27/19 7:20 PM, Dave Martin wrote: > On Wed, Mar 27, 2019 at 05:19:28PM +0530, Amit Daniel Kachhap wrote: >> Hi, >> >> On 3/27/19 4:14 PM, Dave Martin wrote: >>> On Mon, Mar 25, 2019 at 08:05:49PM +0000, Kristina Martsenko wrote: >>>> On 19/03/2019 08:30, Amit Daniel Kachhap wrote: >>>>> This adds sections for KVM API extension for pointer authentication. >>>>> A brief description about usage of pointer authentication for KVM guests >>>>> is added in the arm64 documentations. >>>>> >>>>> Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com> >>>>> Cc: Mark Rutland <mark.rutland@arm.com> >>>>> Cc: Christoffer Dall <christoffer.dall@arm.com> >>>>> Cc: Marc Zyngier <marc.zyngier@arm.com> >>>>> Cc: kvmarm@lists.cs.columbia.edu >>>> >>>> I think it makes sense to also update the Kconfig symbol description for >>>> CONFIG_ARM64_PTR_AUTH, since it currently only mentions userspace >>>> support, but now the option also enables KVM guest support. >>>> >>>> It's also worth mentioning that CONFIG_ARM64_VHE=y is required for guest >>>> support. >>> >>> Is it worth making this dependency explicit in Kconfig? >> Currently there is discrepancy that userspace supports ptrauth in both >> nVHE/VHE mode and KVM guest only in VHE mode. I suppose adding explicit >> dependency flag here makes both of them similar. > > Looking at the history, for SVE this Kconfig restriction has always been > present. Since ptrauth initially upstreamed without an equivalent > restriction in Kconfig, adding it now could be seen as a regression. ok it makes sense to keep it this way. > > So, maybe it's not worth it here. > > You could add a separate option, say > > config ARM64_PTR_AUTH_KVM > bool "Pointer authentication support for KVM guests" > default y > depends on ARM64_PTR_AUTH && ARM64_VHE && KVM > > ...but that may be overkill. I was thinking for adding some details for this in virtualization section in Documentation/arm64/pointer-authentication.txt along with brief comment in arch/arm64/Kconfig.
Thanks, Amit D > > Cheers, > ---Dave >
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