platform: fix page validation issues #512
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This causes a boot failure for me when launching the guest firmware: Please let me know if you need help debugging this further. |
The function `validate_virtual_page_range` is expected only to validate those addresses specified. If the base or end of the address range happens to fall within the middle of a 2 MB page, then the validation must be constrained only to those 4 KB pagees that fall within the requested range and must not include any portion of the 2 MB page that falls outside of that range. In addition, page invalidation is not expected to modify page contents. Signed-off-by: Jon Lange <[email protected]>
The behavior of `pvalidate` on a 2 MB page is undefined if the underlying virtual address mapping is a 4 KB mapping. The instruction requires that the virtual address be appropriately aligned, but if the virtual address is backed by 4 KB pages, the physical address may not be aligned, and the resulting behavior is not defined. To avoid problems, ensure that pvalidate is only attempted on a 2 MB page if the underlying mapping is a 2 MB mapping. Signed-off-by: Jon Lange <[email protected]>
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I see the problem. The logic was entirely wrong (both for the TDP and SNP fixes) but now both of them should work correctly. |
Tested again and it works now. Thanks for fixing this quickly. |
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Validating pages by virtual address may encounter a large span that is backed by 4 KB pages instead of 2 MB pages. If a span is mapped by 4 KB pages, it must always be validated as 4 KB pages regardless of the size and alignment of the virtual address range.