Messages in this thread | | | Date | Tue, 22 Feb 2022 01:10:49 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCHv3.1 2.1/2] x86/coco: Add API to handle encryption mask |
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On Mon, Feb 21, 2022 at 10:05:20PM +0100, Borislav Petkov wrote: > On Sat, Feb 19, 2022 at 03:13:05AM +0300, Kirill A. Shutemov wrote: > > AMD SME/SEV uses a bit in the page table entries to indicate that the > > page is encrypted and not accessible to the VMM. > > > > TDX uses a similar approach, but the polarity of the mask is opposite to > > AMD: if the bit is set the page is accessible to VMM. > > > > Provide vendor-neutral API to deal with the mask: > > > > - cc_mkenc() and cc_mkdec() modify given address to make it > > encrypted/decrypted. It can be applied to phys_addr_t, pgprotval_t > > or page table entry value. > > > > - cc_get_mask() returns encryption or decrypthion mask. It is useful > > Unknown word [encrypthion] in commit message. > Suggestions: ['encryption', 'decryption'] > > Unknown word [decrypthion] in commit message. > Suggestions: ['decryption', 'encryption']
Ughh. Sorry. Will fix.
> > diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c > > index eb7fbd85b77e..fa758247ab57 100644 > > --- a/arch/x86/mm/mem_encrypt_identity.c > > +++ b/arch/x86/mm/mem_encrypt_identity.c > > @@ -603,5 +603,5 @@ void __init sme_enable(struct boot_params *bp) > > out: > > physical_mask &= ~sme_me_mask; > > if (sme_me_mask) > > - cc_init(CC_VENDOR_AMD); > > + cc_init(CC_VENDOR_AMD, sme_me_mask); > > I'm wondering why this is looking weird... an init function with two > arguments which get assigned. I think it would be better if you do: > > cc_set_vendor(CC_VENDOR_XXX); > cc_set_mask(mask); > > and those helpers simply assign to __ro_after_init, local variables. > > IOW, simple setter functions.
I'm not sure it is a good idea. It leaves room for code between these two calls. I believe they conceptually has to initialized in one shot. That's the only way we get consistent state.
-- Kirill A. Shutemov
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