[PATCH v4 0/3] Fix broken SNP support with KVM module built-in

[Ashish Kalra <Ashish.Kalra@amd.com>]

From: Ashish Kalra <ashish.kalra@amd.com>

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 currently 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.

This patch-set adds support to call snp_rmptable_init() early and
directly from iommu_snp_enable() (after checking and enabling IOMMU
SNP support) which enables SNP host support before KVM initialization
with kvm_amd module built-in.

Additionally the patch-set adds support to initialize PSP SEV driver
during KVM module probe time.

This patch-set has been tested with the following cases/scenarios:
1). kvm_amd module and PSP driver built-in.
2). kvm_amd module built-in with intremap=off kernel command line.
3). kvm_amd module built-in with iommu=off kernel command line.
4). kvm_amd and PSP driver built as modules.
5). kvm_amd built as module with iommu=off kernel command line.
6). kvm_amd module as built-in and PSP driver as module.
7). kvm_amd build as a module and PSP driver as built-in.

v4:
- Add warning if SNP support has been checked on IOMMUs and host
SNP support has been enabled but late IOMMU initialization fails
subsequently.
- Add reviewed-by's.

v3:
- Ensure that dropping the device_initcall() happens in the same
patch that wires up the IOMMU code to invoke snp_rmptable_init()
which then makes sure that snp_rmptable_init() is still getting
called and also merge patches 3 & 4.
- Fix commit logs.

v2:
- Drop calling iommu_snp_enable() early before enabling IOMMUs as
IOMMU subsystem gets initialized via subsys_initcall() and hence
snp_rmptable_init() cannot be invoked via subsys_initcall().
- Instead add support to call snp_rmptable_init() early and
directly via iommu_snp_enable().
- Fix commit logs.

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 is initialized if KVM module is built-in

 arch/x86/include/asm/sev.h  |  2 ++
 arch/x86/kvm/svm/sev.c      | 10 ++++++++++
 arch/x86/virt/svm/sev.c     | 23 +++++++----------------
 drivers/crypto/ccp/sp-dev.c | 14 ++++++++++++++
 drivers/iommu/amd/init.c    | 34 ++++++++++++++++++++++++++++++----
 include/linux/psp-sev.h     |  9 +++++++++
 6 files changed, 72 insertions(+), 20 deletions(-)

-- 
2.34.1