Provide "nosnp" boot option via "sev=nosnp" kernel command line to
prevent SEV-SNP[1] capable host kernel from enabling SEV-SNP and
initializing Reverse Map Table (RMP) [1].

On providing sev=nosnp via kernel command line:
cat /sys/module/kvm_amd/parameters/sev_snp should be "N".

This patchset is based on tip/master.

Reference:
[1] https://www.amd.com/content/dam/amd/en/documents/processor-tech-docs/programmer-references/24593.pdf

Changelog:
v3->v4:
  * Remove an irrelevant header (Boris)
  * Rebase on latest tip/master
 
v2->v3:
  * Fix the build warning reported by kernel test robot
  * https://lore.kernel.org/all/20240905143056.48216-1-papaluri@amd.com/

v1->v2:
  * Pick R-b's from Tom.
  * Include only those headers that provide the necessary definitions (Boris)
  * Provide appropriate references to SEV, SNP and RMP (Matthew)
  * https://lore.kernel.org/all/20240903003511.1530454-1-papaluri@amd.com/

Pavan Kumar Paluri (2):
  x86, KVM:SVM: Move sev specific parsing into arch/x86/virt/svm
  x86 KVM:SVM: Provide "nosnp" boot option for sev kernel command line

 .../arch/x86/x86_64/boot-options.rst          |  3 ++
 arch/x86/coco/sev/core.c                      | 44 -------------------
 arch/x86/include/asm/sev-common.h             | 29 ++++++++++++
 arch/x86/virt/svm/Makefile                    |  1 +
 arch/x86/virt/svm/cmdline.c                   | 39 ++++++++++++++++
 5 files changed, 72 insertions(+), 44 deletions(-)
 create mode 100644 arch/x86/virt/svm/cmdline.c


base-commit: 6d3e8e28e20d250d2f3ebb3f5afb63848a2aebf9
-- 
2.34.1