From: Ackerley Tng <[email protected]> Update tdx_gmem_post_populate() to handle cases where a source page is not explicitly provided. Instead of returning -EOPNOTSUPP when src_page is NULL, default to using the page associated with the destination PFN.
This change allows for in-place memory conversion where the data is already present in the target PFN, ensuring the TDX module has a valid source page reference for the TDH.MEM.PAGE.ADD operation. Signed-off-by: Ackerley Tng <[email protected]> Signed-off-by: Sean Christopherson <[email protected]> --- Documentation/virt/kvm/x86/intel-tdx.rst | 4 ++++ arch/x86/kvm/vmx/tdx.c | 11 ++++++++--- 2 files changed, 12 insertions(+), 3 deletions(-) diff --git a/Documentation/virt/kvm/x86/intel-tdx.rst b/Documentation/virt/kvm/x86/intel-tdx.rst index 6a222e9d09541..74357fe87f9ec 100644 --- a/Documentation/virt/kvm/x86/intel-tdx.rst +++ b/Documentation/virt/kvm/x86/intel-tdx.rst @@ -158,6 +158,10 @@ KVM_TDX_INIT_MEM_REGION Initialize @nr_pages TDX guest private memory starting from @gpa with userspace provided data from @source_addr. @source_addr must be PAGE_SIZE-aligned. +If guest_memfd in-place conversion is enabled, pass NULL for @source_addr to +initialize the memory region using memory contents already populated in +guest_memfd memory. + Note, before calling this sub command, memory attribute of the range [gpa, gpa + nr_pages] needs to be private. Userspace can use KVM_SET_MEMORY_ATTRIBUTES to set the attribute. diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index ffe9d0db58c59..56d10333c61a7 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -3198,8 +3198,12 @@ static int tdx_gmem_post_populate(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, if (KVM_BUG_ON(kvm_tdx->page_add_src, kvm)) return -EIO; - if (!src_page) - return -EOPNOTSUPP; + if (!src_page) { + if (!gmem_in_place_conversion) + return -EOPNOTSUPP; + + src_page = pfn_to_page(pfn); + } kvm_tdx->page_add_src = src_page; ret = kvm_tdp_mmu_map_private_pfn(arg->vcpu, gfn, pfn); @@ -3278,7 +3282,8 @@ static int tdx_vcpu_init_mem_region(struct kvm_vcpu *vcpu, struct kvm_tdx_cmd *c break; } - region.source_addr += PAGE_SIZE; + if (region.source_addr) + region.source_addr += PAGE_SIZE; region.gpa += PAGE_SIZE; region.nr_pages--; -- 2.55.0.rc0.738.g0c8ab3ebcc-goog
