[PATCH v15 11/23] KVM: selftests: Set shared attributes for ucall guest_memfd pages

From: Lisa Wang

Date: Thu Oct 01 2026 - 15:40:14 EST


The default attributes for guest_memfd pages without in-place conversion
is private. However, the ucall pages need to be shared between the host
and the guest. Thus, set them as shared.

Signed-off-by: Lisa Wang <wyihan@xxxxxxxxxx>
---
tools/testing/selftests/kvm/lib/ucall_common.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/tools/testing/selftests/kvm/lib/ucall_common.c b/tools/testing/selftests/kvm/lib/ucall_common.c
index 029ce21f9f2f..c03dfc763172 100644
--- a/tools/testing/selftests/kvm/lib/ucall_common.c
+++ b/tools/testing/selftests/kvm/lib/ucall_common.c
@@ -27,6 +27,7 @@ static struct ucall_header *ucall_pool;

void ucall_init(struct kvm_vm *vm, gpa_t mmio_gpa)
{
+ struct userspace_mem_region *region;
struct ucall_header *hdr;
struct ucall *uc;
gva_t gva;
@@ -37,6 +38,13 @@ void ucall_init(struct kvm_vm *vm, gpa_t mmio_gpa)
hdr = (struct ucall_header *)addr_gva2hva(vm, gva);
memset(hdr, 0, sizeof(*hdr));

+ region = vm_get_mem_region(vm, MEM_REGION_DATA);
+ if (region->region.flags & KVM_MEM_GUEST_MEMFD) {
+ size_t aligned_sz = align_up(sizeof(*hdr), vm->page_size);
+
+ vm_mem_set_shared(vm, addr_gva2gpa(vm, gva), aligned_sz);
+ }
+
for (i = 0; i < KVM_MAX_VCPUS; ++i) {
uc = &hdr->ucalls[i];
uc->hva = uc;

--
2.56.0.rc1.315.gc6ed9934b7-goog