Re: [PATCH v3 04/25] KVM: x86/mmu: Add dedicated API to map guest_memfd pfn into TDP MMU
From: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
Date: 2025-10-21 00:10:20
Also in:
kvm, kvm-riscv, kvmarm, linux-arm-kernel, linux-coco, linux-mips, linux-riscv, lkml, loongarch
On Thu, 2025-10-16 at 17:32 -0700, Sean Christopherson wrote:
Add and use a new API for mapping a private pfn from guest_memfd into the TDP MMU from TDX's post-populate hook instead of partially open-coding the functionality into the TDX code. Sharing code with the pre-fault path sounded good on paper, but it's fatally flawed as simulating a fault loses the pfn, and calling back into gmem to re-retrieve the pfn creates locking problems, e.g. kvm_gmem_populate() already holds the gmem invalidation lock. Providing a dedicated API will also removing several MMU exports that ideally would not be exposed outside of the MMU, let alone to vendor code. On that topic, opportunistically drop the kvm_mmu_load() export. Leave kvm_tdp_mmu_gpa_is_mapped() alone for now; the entire commit that added kvm_tdp_mmu_gpa_is_mapped() will be removed in the near future. Cc: Michael Roth <redacted> Cc: Yan Zhao <redacted> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Vishal Annapurve <redacted> Cc: Rick Edgecombe <rick.p.edgecombe@intel.com> Link: https://lore.kernel.org/all/20250709232103.zwmufocd3l7sqk7y@amd.com (local) Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>