[0/4] Fix broken SNP support with KVM module built-in

Message

Ashish Kalra Jan. 22, 2025, 12:59 a.m. UTC

From: Ashish Kalra <[e-mail]>

This patch-set fixes the current SNP host enabling code and effectively SNP
which is broken with respect to the KVM module being built-in.

Essentially SNP host enabling code should be invoked before KVM
initialization, which is currently not the case when KVM is built-in.

SNP host support is enabled in snp_rmptable_init() which is invoked as a
device_initcall(). Here device_initcall() is used as snp_rmptable_init()
expects AMD IOMMU SNP support to be enabled prior to it and the AMD
IOMMU driver enables SNP support after PCI bus enumeration.

The first pre-patch in this patch-set is the AMD IOMMU driver patch
which moves SNP enable check before enabling IOMMUs. With this patch
applied, the final patch in this patch-set calls snp_rmptable_init()
early with subsys_initcall() which then enables SNP host support before
KVM initialization with kvm_amd module built-in. The other two pre-patches
in the patch-set ensure that the dependent PSP SEV driver is initialized
before KVM module if KVM module is built-in.

Fixes: c3b86e61b756 ("x86/cpufeatures: Enable/unmask SEV-SNP CPU feature")

Ashish Kalra (1):
  x86/sev: Fix broken SNP support with KVM module built-in

Sean Christopherson (2):
  crypto: ccp: Add external API interface for PSP module initialization
  KVM: SVM: Ensure PSP module initialized before built-in KVM module

Vasant Hegde (1):
  iommu/amd: Check SNP support before enabling IOMMU

 arch/x86/kvm/svm/sev.c      | 10 ++++++++++
 arch/x86/virt/svm/sev.c     |  2 +-
 drivers/crypto/ccp/sp-dev.c | 12 ++++++++++++
 drivers/crypto/ccp/sp-dev.h |  1 +
 drivers/iommu/amd/init.c    |  3 ++-
 include/linux/psp-sev.h     | 11 +++++++++++
 6 files changed, 37 insertions(+), 2 deletions(-)