Messages in this thread | | | Date | Tue, 26 Apr 2022 07:16:16 +0200 | From | Juergen Gross <> | Subject | Re: [PATCH V1 3/6] xen/virtio: Add option to restrict memory access under Xen |
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On 25.04.22 23:25, Borislav Petkov wrote: > On Mon, Apr 25, 2022 at 11:38:36PM +0300, Oleksandr wrote: >> diff --git a/include/linux/cc_platform.h b/include/linux/cc_platform.h >> index efd8205..d06bc7a 100644 >> --- a/include/linux/cc_platform.h >> +++ b/include/linux/cc_platform.h >> @@ -72,6 +72,19 @@ enum cc_attr { >> * Examples include TDX guest & SEV. >> */ >> CC_ATTR_GUEST_UNROLL_STRING_IO, >> + >> + /** >> + * @CC_ATTR_GUEST_MEM_ACCESS_RESTRICTED: Restricted memory access to >> + * Guest memory is active >> + * >> + * The platform/OS is running as a guest/virtual machine and uses >> + * the restricted access to its memory. This attribute is set if >> either >> + * Guest memory encryption or restricted memory access using Xen >> grant >> + * mappings is active. >> + * >> + * Examples include Xen guest and SEV. > > Wait, whaaat? > > The cc_platform* stuff is for *confidential computing* guests to check > different platform aspects. > > From quickly skimming over this, this looks like a misuse to me.
Christoph suggested (rather firmly) this would be the way to go.
> > Why can't you query this from the hypervisor just like you do your other > querying about what is supported, etc? Hypercalls, CPUID, whatever...
This is needed on guest side at a rather hypervisor independent place.
So a capability of some sort seems appropriate.
Another suggestion of mine was to have a callback (or flag) in struct x86_hyper_runtime for that purpose.
Juergen [unhandled content-type:application/pgp-keys][unhandled content-type:application/pgp-signature] | |