Re: [edk2-devel] [PATCH v3 08/24] OvmfPkg/BaseMemEncryptSevLib: Re-organize page state change support

["Gerd Hoffmann" <kraxel@redhat.com>]

On Fri, Mar 08, 2024 at 07:31:11AM -0800, Lendacky, Thomas via groups.io wrote:
> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4654
> 
> In preparation for running under an SVSM at VMPL1 or higher (higher
> numerically, lower privilege), re-organize the way a page state change
> is performed in order to free up the GHCB for use by the SVSM support.
> 
> Currently, the page state change logic directly uses the GHCB shared
> buffer to build the page state change structures. However, this will be
> in conflict with the use of the GHCB should an SVSM call be required.
> 
> Instead, use a separate buffer (an area in the workarea during SEC and
> an allocated page during PEI/DXE) to hold the page state change request
> and only update the GHCB shared buffer as needed.
> 
> Since the information is copied to, and operated on, in the GHCB shared
> buffer this has the added benefit of not requiring to save the start and
> end entries for use when validating the memory during the page state
> change sequence.
> 
> Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
> Cc: Erdem Aktas <erdemaktas@google.com>
> Cc: Gerd Hoffmann <kraxel@redhat.com>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Laszlo Ersek <lersek@redhat.com>
> Cc: Michael Roth <michael.roth@amd.com>
> Cc: Min Xu <min.m.xu@intel.com>
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>

Acked-by: Gerd Hoffmann <kraxel@redhat.com>



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