Commit 87c810160ed7 for kernel

commit 87c810160ed738cd983e4a65ebe9709927c702c9
Author: Sean Christopherson <seanjc@google.com>
Date:   Tue May 12 08:56:34 2026 -0700

    KVM: selftests: Ensure gmem file sizes are multiple of host page size

    When creating a guest_memfd file and associated memslot to validate shared
    guest memory, size the file+memslot to the maximum of the host or guest
    page size.  Attempting to allocate a single guest page will fail if the
    host page size is greater than the guest page size, as KVM requires that
    the size of memslots and guest_memfd files are a multiple of the host page
    size.

    For simplicity, verify the entire file can be shared between guest and host,
    e.g. instead of trying to validate "partial" mappings.

    Fixes: 42188667be38 ("KVM: selftests: Add guest_memfd testcase to fault-in on !mmap()'d memory")
    Reported-by: Zenghui Yu <zenghui.yu@linux.dev>
    Closes: https://lore.kernel.org/all/0064952b-048c-455d-ad89-e27e5cb82591@linux.dev
    Signed-off-by: Sean Christopherson <seanjc@google.com>
    Message-ID: <20260512155634.772602-1-seanjc@google.com>
    Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c
index d6528c6f5e03..253e748c1d4a 100644
--- a/tools/testing/selftests/kvm/guest_memfd_test.c
+++ b/tools/testing/selftests/kvm/guest_memfd_test.c
@@ -510,7 +510,12 @@ static void test_guest_memfd_guest(void)
 		    "Default VM type should support INIT_SHARED, supported flags = 0x%x",
 		    vm_check_cap(vm, KVM_CAP_GUEST_MEMFD_FLAGS));

-	size = vm->page_size;
+	/*
+	 * Use the max of the host or guest page size for all operations, as
+	 * KVM requires guest_memfd files and memslots to be sized to multiples
+	 * of the host page size.
+	 */
+	size = max_t(size_t, vm->page_size, page_size);
 	fd = vm_create_guest_memfd(vm, size, GUEST_MEMFD_FLAG_MMAP |
 					     GUEST_MEMFD_FLAG_INIT_SHARED);
 	vm_set_user_memory_region2(vm, slot, KVM_MEM_GUEST_MEMFD, gpa, size, NULL, fd, 0);
@@ -519,7 +524,7 @@ static void test_guest_memfd_guest(void)
 	memset(mem, 0xaa, size);
 	kvm_munmap(mem, size);

-	virt_pg_map(vm, gpa, gpa);
+	virt_map(vm, gpa, gpa, size / vm->page_size);
 	vcpu_args_set(vcpu, 2, gpa, size);
 	vcpu_run(vcpu);