Fix two bugs I introduced when adding the enable_mmio_caching module param. Bug #1 is that KVM unintentionally makes disabling caching due to a config incompatibility "sticky", e.g. disabling caching because there are no reserved PA bits prevents KVM from enabling when "switching" to an EPT config (doesn't rely on PA bits) or when SVM adjusts the MMIO masks to account for C-bit shenanigans (even if MAXPHYADDR=52 and C-bit=51, there can be reserved PA bits due to the "real" MAXPHYADDR being reduced). Bug #2 is that KVM doesn't explicitly check that MMIO caching is enabled when doing SEV-ES setup. Prior to the module param, MMIO caching was guaranteed when SEV-ES could be enabled as SEV-ES-capable CPUs effectively guarantee there will be at least one reserved PA bit (see above). With the module param, userspace can explicitly disable MMIO caching, thus silently breaking SEV-ES. I believe I tested all combinations of things getting disabled and enabled by hacking kvm_mmu_reset_all_pte_masks() to disable MMIO caching on a much lower MAXPHYADDR, e.g. 43 instead of 52. That said, definitely wait for a thumbs up from the AMD folks before queueing. Sean Christopherson (4): KVM: x86: Tag kvm_mmu_x86_module_init() with __init KVM: x86/mmu: Fully re-evaluate MMIO caching when SPTE masks change KVM: SVM: Adjust MMIO masks (for caching) before doing SEV(-ES) setup KVM: SVM: Disable SEV-ES support if MMIO caching is disable arch/x86/include/asm/kvm_host.h | 2 +- arch/x86/kvm/mmu.h | 2 ++ arch/x86/kvm/mmu/mmu.c | 6 +++++- arch/x86/kvm/mmu/spte.c | 20 ++++++++++++++++++++ arch/x86/kvm/mmu/spte.h | 3 +-- arch/x86/kvm/svm/sev.c | 10 ++++++++++ arch/x86/kvm/svm/svm.c | 9 ++++++--- 7 files changed, 45 insertions(+), 7 deletions(-) base-commit: 1a4d88a361af4f2e91861d632c6a1fe87a9665c2 -- 2.37.1.455.g008518b4e5-goog
