[PATCH v7 22/42] KVM: selftests: Create gmem fd before "regular" fd when adding memslot
From: Ackerley Tng via B4 Relay <devnull+ackerleytng.google.com@kernel.org>
Date: 2026-05-23 00:18:05
Also in:
b4-sent, kvm, linux-coco, linux-doc, linux-kselftest, linux-mm, lkml
Subsystem:
kernel selftest framework, kernel virtual machine (kvm), the rest · Maintainers:
Shuah Khan, Paolo Bonzini, Linus Torvalds
From: Sean Christopherson <seanjc@google.com> When adding a memslot associated a guest_memfd instance, create/dup the guest_memfd before creating the "normal" backing file. This will allow dup'ing the gmem fd as the normal fd when guest_memfd supports mmap(), i.e. to make guest_memfd the _only_ backing source for the memslot. Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Fuad Tabba <redacted> Signed-off-by: Ackerley Tng <redacted> --- tools/testing/selftests/kvm/lib/kvm_util.c | 45 +++++++++++++++--------------- 1 file changed, 23 insertions(+), 22 deletions(-)
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 2a76eca7029d3..df73b23a4c66a 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c@@ -1054,6 +1054,29 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type, if (alignment > 1) region->mmap_size += alignment; + if (flags & KVM_MEM_GUEST_MEMFD) { + if (guest_memfd < 0) { + u32 guest_memfd_flags = 0; + + TEST_ASSERT(!guest_memfd_offset, + "Offset must be zero when creating new guest_memfd"); + guest_memfd = vm_create_guest_memfd(vm, mem_size, guest_memfd_flags); + } else { + /* + * Install a unique fd for each memslot so that the fd + * can be closed when the region is deleted without + * needing to track if the fd is owned by the framework + * or by the caller. + */ + guest_memfd = kvm_dup(guest_memfd); + } + + region->region.guest_memfd = guest_memfd; + region->region.guest_memfd_offset = guest_memfd_offset; + } else { + region->region.guest_memfd = -1; + } + region->fd = -1; if (backing_src_is_shared(src_type)) region->fd = kvm_memfd_alloc(region->mmap_size,
@@ -1083,28 +1106,6 @@ void vm_mem_add(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type, region->backing_src_type = src_type; - if (flags & KVM_MEM_GUEST_MEMFD) { - if (guest_memfd < 0) { - u32 guest_memfd_flags = 0; - TEST_ASSERT(!guest_memfd_offset, - "Offset must be zero when creating new guest_memfd"); - guest_memfd = vm_create_guest_memfd(vm, mem_size, guest_memfd_flags); - } else { - /* - * Install a unique fd for each memslot so that the fd - * can be closed when the region is deleted without - * needing to track if the fd is owned by the framework - * or by the caller. - */ - guest_memfd = kvm_dup(guest_memfd); - } - - region->region.guest_memfd = guest_memfd; - region->region.guest_memfd_offset = guest_memfd_offset; - } else { - region->region.guest_memfd = -1; - } - region->unused_phy_pages = sparsebit_alloc(); if (vm_arch_has_protected_memory(vm)) region->protected_phy_pages = sparsebit_alloc();
--
2.54.0.794.g4f17f83d09-goog