Add a guest_memfd testcase to verify that a vCPU can fault-in guest_memfd memory that supports mmap(), but that is not currently mapped into host userspace and/or has a userspace address (in the memslot) that points at something other than the target guest_memfd range. Mapping guest_memfd memory into the guest is supposed to operate completely independently from any userspace mappings. Signed-off-by: Sean Christopherson --- .../testing/selftests/kvm/guest_memfd_test.c | 64 +++++++++++++++++++ 1 file changed, 64 insertions(+) diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c index 088053d5f0f5..b86bf89a71e0 100644 --- a/tools/testing/selftests/kvm/guest_memfd_test.c +++ b/tools/testing/selftests/kvm/guest_memfd_test.c @@ -13,6 +13,7 @@ #include #include +#include #include #include #include @@ -21,6 +22,7 @@ #include "kvm_util.h" #include "test_util.h" +#include "ucall_common.h" static void test_file_read_write(int fd) { @@ -298,6 +300,66 @@ static void test_guest_memfd(unsigned long vm_type) kvm_vm_free(vm); } +static void guest_code(uint8_t *mem, uint64_t size) +{ + size_t i; + + for (i = 0; i < size; i++) + __GUEST_ASSERT(mem[i] == 0xaa, + "Guest expected 0xaa at offset %lu, got 0x%x", i, mem[i]); + + memset(mem, 0xff, size); + GUEST_DONE(); +} + +static void test_guest_memfd_guest(void) +{ + /* + * Skip the first 4gb and slot0. slot0 maps <1gb and is used to back + * the guest's code, stack, and page tables, and low memory contains + * the PCI hole and other MMIO regions that need to be avoided. + */ + const uint64_t gpa = SZ_4G; + const int slot = 1; + + struct kvm_vcpu *vcpu; + struct kvm_vm *vm; + uint8_t *mem; + size_t size; + int fd, i; + + if (!kvm_has_cap(KVM_CAP_GUEST_MEMFD_MMAP)) + return; + + vm = __vm_create_shape_with_one_vcpu(VM_SHAPE_DEFAULT, &vcpu, 1, guest_code); + + TEST_ASSERT(vm_check_cap(vm, KVM_CAP_GUEST_MEMFD_MMAP), + "Default VM type should always support guest_memfd mmap()"); + + size = vm->page_size; + fd = vm_create_guest_memfd(vm, size, GUEST_MEMFD_FLAG_MMAP); + vm_set_user_memory_region2(vm, slot, KVM_MEM_GUEST_MEMFD, gpa, size, NULL, fd, 0); + + mem = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + TEST_ASSERT(mem != MAP_FAILED, "mmap() on guest_memfd failed"); + memset(mem, 0xaa, size); + munmap(mem, size); + + virt_pg_map(vm, gpa, gpa); + vcpu_args_set(vcpu, 2, gpa, size); + vcpu_run(vcpu); + + TEST_ASSERT_EQ(get_ucall(vcpu, NULL), UCALL_DONE); + + mem = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + TEST_ASSERT(mem != MAP_FAILED, "mmap() on guest_memfd failed"); + for (i = 0; i < size; i++) + TEST_ASSERT_EQ(mem[i], 0xff); + + close(fd); + kvm_vm_free(vm); +} + int main(int argc, char *argv[]) { unsigned long vm_types, vm_type; @@ -314,4 +376,6 @@ int main(int argc, char *argv[]) for_each_set_bit(vm_type, &vm_types, BITS_PER_TYPE(vm_types)) test_guest_memfd(vm_type); + + test_guest_memfd_guest(); } -- 2.50.1.552.g942d659e1b-goog