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    SubjectRe: [PATCH v6 5/5] x86/sev: Add SNP-specific unaccepted memory support
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    On 12/8/22 16:12, Kirill A. Shutemov wrote:
    > On Thu, Dec 08, 2022 at 09:29:13AM -0600, Tom Lendacky wrote:
    >> Add SNP-specific hooks to the unaccepted memory support in the boot
    >> path (__accept_memory()) and the core kernel (accept_memory()) in order
    >> to support booting SNP guests when unaccepted memory is present. Without
    >> this support, SNP guests will fail to boot and/or panic() when unaccepted
    >> memory is present in the EFI memory map.
    >>
    >> The process of accepting memory under SNP involves invoking the hypervisor
    >> to perform a page state change for the page to private memory and then
    >> issuing a PVALIDATE instruction to accept the page.
    >>
    >> Since the boot path and the core kernel paths perform similar operations,
    >> move the pvalidate_pages() and vmgexit_psc() functions into sev-shared.c
    >> to avoid code duplication.
    >>
    >> Create the new header file arch/x86/boot/compressed/sev.h because adding
    >> the function declaration to any of the existing SEV related header files
    >> pulls in too many other header files, causing the build to fail.
    >>
    >> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
    >> ---
    >> arch/x86/Kconfig | 1 +
    >> arch/x86/boot/compressed/mem.c | 3 +
    >> arch/x86/boot/compressed/sev.c | 54 ++++++++++++++-
    >> arch/x86/boot/compressed/sev.h | 23 +++++++
    >> arch/x86/include/asm/sev.h | 3 +
    >> arch/x86/kernel/sev-shared.c | 103 +++++++++++++++++++++++++++++
    >> arch/x86/kernel/sev.c | 112 ++++----------------------------
    >> arch/x86/mm/unaccepted_memory.c | 4 ++
    >> 8 files changed, 204 insertions(+), 99 deletions(-)
    >> create mode 100644 arch/x86/boot/compressed/sev.h
    >>
    >> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
    >> index d88f61940aa7..0704d4795919 100644
    >> --- a/arch/x86/Kconfig
    >> +++ b/arch/x86/Kconfig
    >> @@ -1549,6 +1549,7 @@ config AMD_MEM_ENCRYPT
    >> select INSTRUCTION_DECODER
    >> select ARCH_HAS_CC_PLATFORM
    >> select X86_MEM_ENCRYPT
    >> + select UNACCEPTED_MEMORY
    >> help
    >> Say yes to enable support for the encryption of system memory.
    >> This requires an AMD processor that supports Secure Memory
    >
    > I think it misses "depends on EFI_STUB".

    Ah, good catch, thanks. I'll update the series to add that.

    Thanks,
    Tom

    >
    > The code I've submitted contains "select EFI_STUB", but it causes build
    > issues for some configurations. I've changed it to "depends on" in git.
    >

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