Re: [PATCHv6 25/30] x86/tdx: Make pages shared in ioremap()

Dave Hansen
2022-03-16T22:06:57Z

On 3/15/22 19:08, Kirill A. Shutemov wrote:
> In TDX guests, guest memory is protected from host access. If a guest
> performs I/O, it needs to explicitly share the I/O memory with the host.
>
> Make all ioremap()ed pages that are not backed by normal memory
> (IORES_DESC_NONE or IORES_DESC_RESERVED) mapped as shared.
>
> The permissions in PAGE_KERNEL_IO already work for "decrypted" memory
> on AMD SEV/SME systems. That means that they have no need to make a
> pgprot_decrypted() call.
>
> TDX guests, on the other hand, _need_ change to PAGE_KERNEL_IO for
> "decrypted" mappings. Add a pgprot_decrypted() for TDX.

Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>