Michael Kelley c7b5254bd8 x86/mm: Handle decryption/re-encryption of bss_decrypted consistently
sme_postprocess_startup() decrypts the bss_decrypted section when
sme_me_mask is non-zero.

mem_encrypt_free_decrypted_mem() re-encrypts the unused portion based
on CC_ATTR_MEM_ENCRYPT.

In a Hyper-V guest VM using vTOM, these conditions are not equivalent
as sme_me_mask is always zero when using vTOM. Consequently,
mem_encrypt_free_decrypted_mem() attempts to re-encrypt memory that was
never decrypted.

So check sme_me_mask in mem_encrypt_free_decrypted_mem() too.

Hyper-V guests using vTOM don't need the bss_decrypted section to be
decrypted, so skipping the decryption/re-encryption doesn't cause a
problem.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/1678329614-3482-5-git-send-email-mikelley@microsoft.com
2023-03-27 09:23:21 +02:00
2022-09-28 09:02:20 +02:00
2023-03-19 13:27:55 -07:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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