[PATCH v5 7/7] KVM: selftests: x86: Add test for KVM_PRE_FAULT_MEMORY
From: Paolo Bonzini
Date: Wed Jul 10 2024 - 13:45:54 EST
From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
Add a test case to exercise KVM_PRE_FAULT_MEMORY and run the guest to access the
pre-populated area. It tests KVM_PRE_FAULT_MEMORY ioctl for KVM_X86_DEFAULT_VM
and KVM_X86_SW_PROTECTED_VM.
Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
Message-ID: <32427791ef42e5efaafb05d2ac37fa4372715f47.1712785629.git.isaku.yamahata@xxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
tools/include/uapi/linux/kvm.h | 14 +-
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/pre_fault_memory_test.c | 146 ++++++++++++++++++
3 files changed, 159 insertions(+), 2 deletions(-)
create mode 100644 tools/testing/selftests/kvm/pre_fault_memory_test.c
diff --git a/tools/include/uapi/linux/kvm.h b/tools/include/uapi/linux/kvm.h
index ea32b101b999..e5af8c692dc0 100644
--- a/tools/include/uapi/linux/kvm.h
+++ b/tools/include/uapi/linux/kvm.h
@@ -917,6 +917,7 @@ struct kvm_enable_cap {
#define KVM_CAP_MEMORY_ATTRIBUTES 233
#define KVM_CAP_GUEST_MEMFD 234
#define KVM_CAP_VM_TYPES 235
+#define KVM_CAP_PRE_FAULT_MEMORY 236
struct kvm_irq_routing_irqchip {
__u32 irqchip;
@@ -1221,9 +1222,9 @@ struct kvm_vfio_spapr_tce {
/* Available with KVM_CAP_SPAPR_RESIZE_HPT */
#define KVM_PPC_RESIZE_HPT_PREPARE _IOR(KVMIO, 0xad, struct kvm_ppc_resize_hpt)
#define KVM_PPC_RESIZE_HPT_COMMIT _IOR(KVMIO, 0xae, struct kvm_ppc_resize_hpt)
-/* Available with KVM_CAP_PPC_RADIX_MMU or KVM_CAP_PPC_MMU_HASH_V3 */
+/* Available with KVM_CAP_PPC_MMU_RADIX or KVM_CAP_PPC_MMU_HASH_V3 */
#define KVM_PPC_CONFIGURE_V3_MMU _IOW(KVMIO, 0xaf, struct kvm_ppc_mmuv3_cfg)
-/* Available with KVM_CAP_PPC_RADIX_MMU */
+/* Available with KVM_CAP_PPC_MMU_RADIX */
#define KVM_PPC_GET_RMMU_INFO _IOW(KVMIO, 0xb0, struct kvm_ppc_rmmu_info)
/* Available with KVM_CAP_PPC_GET_CPU_CHAR */
#define KVM_PPC_GET_CPU_CHAR _IOR(KVMIO, 0xb1, struct kvm_ppc_cpu_char)
@@ -1548,4 +1549,13 @@ struct kvm_create_guest_memfd {
__u64 reserved[6];
};
+#define KVM_PRE_FAULT_MEMORY _IOWR(KVMIO, 0xd5, struct kvm_pre_fault_memory)
+
+struct kvm_pre_fault_memory {
+ __u64 gpa;
+ __u64 size;
+ __u64 flags;
+ __u64 padding[5];
+};
+
#endif /* __LINUX_KVM_H */
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index ce8ff8e8ce3a..e915d4ae1793 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -145,6 +145,7 @@ TEST_GEN_PROGS_x86_64 += set_memory_region_test
TEST_GEN_PROGS_x86_64 += steal_time
TEST_GEN_PROGS_x86_64 += kvm_binary_stats_test
TEST_GEN_PROGS_x86_64 += system_counter_offset_test
+TEST_GEN_PROGS_x86_64 += pre_fault_memory_test
# Compiled outputs used by test targets
TEST_GEN_PROGS_EXTENDED_x86_64 += x86_64/nx_huge_pages_test
diff --git a/tools/testing/selftests/kvm/pre_fault_memory_test.c b/tools/testing/selftests/kvm/pre_fault_memory_test.c
new file mode 100644
index 000000000000..0350a8896a2f
--- /dev/null
+++ b/tools/testing/selftests/kvm/pre_fault_memory_test.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2024, Intel, Inc
+ *
+ * Author:
+ * Isaku Yamahata <isaku.yamahata at gmail.com>
+ */
+#include <linux/sizes.h>
+
+#include <test_util.h>
+#include <kvm_util.h>
+#include <processor.h>
+
+/* Arbitrarily chosen values */
+#define TEST_SIZE (SZ_2M + PAGE_SIZE)
+#define TEST_NPAGES (TEST_SIZE / PAGE_SIZE)
+#define TEST_SLOT 10
+
+static void guest_code(uint64_t base_gpa)
+{
+ volatile uint64_t val __used;
+ int i;
+
+ for (i = 0; i < TEST_NPAGES; i++) {
+ uint64_t *src = (uint64_t *)(base_gpa + i * PAGE_SIZE);
+
+ val = *src;
+ }
+
+ GUEST_DONE();
+}
+
+static void pre_fault_memory(struct kvm_vcpu *vcpu, u64 gpa, u64 size,
+ u64 left)
+{
+ struct kvm_pre_fault_memory range = {
+ .gpa = gpa,
+ .size = size,
+ .flags = 0,
+ };
+ u64 prev;
+ int ret, save_errno;
+
+ do {
+ prev = range.size;
+ ret = __vcpu_ioctl(vcpu, KVM_PRE_FAULT_MEMORY, &range);
+ save_errno = errno;
+ TEST_ASSERT((range.size < prev) ^ (ret < 0),
+ "%sexpecting range.size to change on %s",
+ ret < 0 ? "not " : "",
+ ret < 0 ? "failure" : "success");
+ } while (ret >= 0 ? range.size : save_errno == EINTR);
+
+ TEST_ASSERT(range.size == left,
+ "Completed with %lld bytes left, expected %" PRId64,
+ range.size, left);
+
+ if (left == 0)
+ __TEST_ASSERT_VM_VCPU_IOCTL(!ret, "KVM_PRE_FAULT_MEMORY", ret, vcpu->vm);
+ else
+ /* No memory slot causes RET_PF_EMULATE. it results in -ENOENT. */
+ __TEST_ASSERT_VM_VCPU_IOCTL(ret && save_errno == ENOENT,
+ "KVM_PRE_FAULT_MEMORY", ret, vcpu->vm);
+}
+
+static void __test_pre_fault_memory(unsigned long vm_type, bool private)
+{
+ const struct vm_shape shape = {
+ .mode = VM_MODE_DEFAULT,
+ .type = vm_type,
+ };
+ struct kvm_vcpu *vcpu;
+ struct kvm_run *run;
+ struct kvm_vm *vm;
+ struct ucall uc;
+
+ uint64_t guest_test_phys_mem;
+ uint64_t guest_test_virt_mem;
+ uint64_t alignment, guest_page_size;
+
+ vm = vm_create_shape_with_one_vcpu(shape, &vcpu, guest_code);
+
+ alignment = guest_page_size = vm_guest_mode_params[VM_MODE_DEFAULT].page_size;
+ guest_test_phys_mem = (vm->max_gfn - TEST_NPAGES) * guest_page_size;
+#ifdef __s390x__
+ alignment = max(0x100000UL, guest_page_size);
+#else
+ alignment = SZ_2M;
+#endif
+ guest_test_phys_mem = align_down(guest_test_phys_mem, alignment);
+ guest_test_virt_mem = guest_test_phys_mem & ((1ULL << (vm->va_bits - 1)) - 1);
+
+ vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
+ guest_test_phys_mem, TEST_SLOT, TEST_NPAGES,
+ private ? KVM_MEM_GUEST_MEMFD : 0);
+ virt_map(vm, guest_test_virt_mem, guest_test_phys_mem, TEST_NPAGES);
+
+ if (private)
+ vm_mem_set_private(vm, guest_test_phys_mem, TEST_SIZE);
+ pre_fault_memory(vcpu, guest_test_phys_mem, SZ_2M, 0);
+ pre_fault_memory(vcpu, guest_test_phys_mem + SZ_2M, PAGE_SIZE * 2, PAGE_SIZE);
+ pre_fault_memory(vcpu, guest_test_phys_mem + TEST_SIZE, PAGE_SIZE, PAGE_SIZE);
+
+ vcpu_args_set(vcpu, 1, guest_test_virt_mem);
+ vcpu_run(vcpu);
+
+ run = vcpu->run;
+ TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
+ "Wanted KVM_EXIT_IO, got exit reason: %u (%s)",
+ run->exit_reason, exit_reason_str(run->exit_reason));
+
+ switch (get_ucall(vcpu, &uc)) {
+ case UCALL_ABORT:
+ REPORT_GUEST_ASSERT(uc);
+ break;
+ case UCALL_DONE:
+ break;
+ default:
+ TEST_FAIL("Unknown ucall 0x%lx.", uc.cmd);
+ break;
+ }
+
+ kvm_vm_free(vm);
+}
+
+static void test_pre_fault_memory(unsigned long vm_type, bool private)
+{
+ if (vm_type && !(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(vm_type))) {
+ pr_info("Skipping tests for vm_type 0x%lx\n", vm_type);
+ return;
+ }
+
+ __test_pre_fault_memory(vm_type, private);
+}
+
+int main(int argc, char *argv[])
+{
+ TEST_REQUIRE(kvm_check_cap(KVM_CAP_PRE_FAULT_MEMORY));
+
+ test_pre_fault_memory(0, false);
+#ifdef __x86_64__
+ test_pre_fault_memory(KVM_X86_SW_PROTECTED_VM, false);
+ test_pre_fault_memory(KVM_X86_SW_PROTECTED_VM, true);
+#endif
+ return 0;
+}
--
2.43.0