Messages in this thread | | | Subject | Re: [RFC v2-fix-v2 1/1] x86: Introduce generic protected guest abstractionn | From | Tom Lendacky <> | Date | Fri, 4 Jun 2021 17:01:31 -0500 |
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On 6/3/21 1:15 PM, Borislav Petkov wrote: > From f1e9f051c86b09fe660f49b0307bc7c6cec5e6f4 Mon Sep 17 00:00:00 2001 > From: Borislav Petkov <bp@suse.de> > Date: Thu, 3 Jun 2021 20:03:31 +0200 > Subject: Convert sme_active() > > */ > - if (sme_active()) > + if (protected_guest_has(VM_HOST_MEM_ENCRYPT)) > swiotlb = 1;
I still feel this is confusing. SME is a host/bare-metal technology, so calling protected_guest_has() seems odd and using VM_HOST_MEM_ENCRYPT, where I assume VM is short for virtual machine, also seems odd.
How about just protected_os_has()? Then you could have - HOST_MEM_ENCRYPT for host memory encryption - GUEST_MEM_ENCRYPT for guest memory encryption - MEM_ENCRYPT for either host or guest memory encryption.
The first is analogous to sme_active(), the second to sev_active() and the third to mem_encrypt_active(). Just my opinion, though...
> > return swiotlb; > diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c > index 01a224fdb897..3aa2658ced52 100644 > --- a/arch/x86/kernel/sev.c > +++ b/arch/x86/kernel/sev.c > @@ -1409,6 +1409,11 @@ bool sev_protected_guest_has(unsigned long flag) > case VM_MEM_ENCRYPT: > case VM_MEM_ENCRYPT_ACTIVE: > return true; > + case VM_HOST_MEM_ENCRYPT: > + return sme_me_mask && !sev_active(); > + default: > + WARN_ON_ONCE(1); > + return false;
I don't think you want a WARN_ON_ONCE() here. The code will be written to work with either SEV or TDX, so we shouldn't warn on a check for a TDX supported feature when running on AMD (or vice-versa).
Thanks, Tom
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