Messages in this thread | | | Date | Tue, 15 Feb 2022 09:55:16 -0600 | Subject | Re: [PATCHv2 22/29] x86/tdx: Make pages shared in ioremap() | From | Tom Lendacky <> |
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On 2/15/22 09:41, Kirill A. Shutemov wrote: > On Tue, Feb 15, 2022 at 08:49:34AM -0600, Tom Lendacky wrote: >> On 2/14/22 16:09, Kirill A. Shutemov wrote: >>> On Mon, Feb 07, 2022 at 06:28:04PM +0100, Borislav Petkov wrote: >>>> On Mon, Feb 07, 2022 at 08:57:39AM -0800, Dave Hansen wrote: >>>>> We can surely *do* this with cc_something() helpers. It's just not as >>>>> easy as making cc_set/cc_clear(). >>>> >>>> Sure, that's easy: cc_pgprot_{enc,dec}() or so. >>> >>> So, I've ended up with this in <asm/pgtable.h> >>> >>> /* >>> * Macros to add or remove encryption attribute >>> */ >>> #ifdef CONFIG_ARCH_HAS_CC_PLATFORM >>> pgprotval_t cc_enc(pgprotval_t protval); >>> pgprotval_t cc_dec(pgprotval_t protval); >>> #define pgprot_encrypted(prot) __pgprot(cc_enc(pgprot_val(prot))) >>> #define pgprot_decrypted(prot) __pgprot(cc_dec(pgprot_val(prot))) >>> #else >>> #define pgprot_encrypted(prot) (prot) >>> #define pgprot_decrypted(prot) (prot) >>> #endif >> >> A couple of things. I think cc_pgprot_enc() and cc_pgprot_dec() would be >> more descriptive/better names to use here. >> >> Also, can they be defined in include/linux/cc_platform.h (with two versions >> based on CONFIG_ARCH_HAS_CC_PLATFORM) and have that included here? Or is >> there some header file include issues when trying to include it? That would >> clean this block up into just two lines. > > Well, pgprotval_t is x86-specific. It cannot be used in generic headers.
Ah, right.
> We can use u64 here instead. It is wider than pgprotval_t on 2-level > paging x86, but should work.
Hmm..., yeah. Maybe unsigned long? CONFIG_ARCH_HAS_CC_PLATFORM is X86_64 only, so 2-level paging wouldn't be applicable when an unsigned long is 64-bits?
I'll let the maintainers weigh in on that.
> > But with u64 as type, I'm not sure 'pgprot' in the name is jutified.
Maybe cc_mask_{enc,dec}()? It just sounds like cc_{enc,dec}() is actually performing encryption or decryption and can be confusing.
Thanks, Tom
> > Hm? >
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