| From | Thomas Gleixner <> | Subject | Re: [PATCHv6 05/30] x86/tdx: Exclude shared bit from __PHYSICAL_MASK | Date | Thu, 17 Mar 2022 01:16:00 +0100 |
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On Wed, Mar 16 2022 at 05:08, Kirill A. Shutemov wrote: > @@ -82,6 +82,14 @@ void __init tdx_early_init(void) > > cc_set_vendor(CC_VENDOR_INTEL); > > + /* > + * All bits above GPA width are reserved and kernel treats shared bit > + * as flag, not as part of physical address. > + * > + * Adjust physical mask to only cover valid GPA bits. > + */ > + physical_mask &= GENMASK_ULL(gpa_width - 2, 0); > +
Hrm. I forgot about the second use case for gpa_width, but my comment about ordering still stands. OTOH:
GENMASK_ULL(gpa_width - 2, 0) == BIT_UL(gpa_width - 1) - 1
right? So you really can consolidate on the fact that cc_mask is a single bit which is above the guests physical address space boundary.
I.e. make the code tell the story instead of adding lengthy comments explaining the obfuscation.
Thanks,
tglx
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