Re: [PATCH v2 2/2] selftests: kvm: Add mem_slot_test test
From: Wainer dos Santos Moschetta
Date: Mon Apr 06 2020 - 13:11:08 EST
On 4/4/20 4:32 AM, Andrew Jones wrote:
On Fri, Apr 03, 2020 at 02:24:28PM -0300, Wainer dos Santos Moschetta wrote:
This patch introduces the mem_slot_test test which checks
an VM can have added memory slots up to the limit defined in
KVM_CAP_NR_MEMSLOTS. Then attempt to add one more slot to
verify it fails as expected.
Signed-off-by: Wainer dos Santos Moschetta <wainersm@xxxxxxxxxx>
---
tools/testing/selftests/kvm/.gitignore | 1 +
tools/testing/selftests/kvm/Makefile | 3 +
tools/testing/selftests/kvm/mem_slot_test.c | 85 +++++++++++++++++++++
3 files changed, 89 insertions(+)
create mode 100644 tools/testing/selftests/kvm/mem_slot_test.c
diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index 16877c3daabf..232f24d6931a 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -22,3 +22,4 @@
/dirty_log_test
/kvm_create_max_vcpus
/steal_time
+/mem_slot_test
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 712a2ddd2a27..69b44178f48b 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -33,12 +33,14 @@ TEST_GEN_PROGS_x86_64 += demand_paging_test
TEST_GEN_PROGS_x86_64 += dirty_log_test
TEST_GEN_PROGS_x86_64 += kvm_create_max_vcpus
TEST_GEN_PROGS_x86_64 += steal_time
+TEST_GEN_PROGS_x86_64 += mem_slot_test
TEST_GEN_PROGS_aarch64 += clear_dirty_log_test
TEST_GEN_PROGS_aarch64 += demand_paging_test
TEST_GEN_PROGS_aarch64 += dirty_log_test
TEST_GEN_PROGS_aarch64 += kvm_create_max_vcpus
TEST_GEN_PROGS_aarch64 += steal_time
+TEST_GEN_PROGS_aarch64 += mem_slot_test
kvm selftests has a bad case of OCD when it comes to lists of tests. In
the .gitignore and the Makefile we keep our tests in alphabetical order.
Maybe we should stop, because it's a bit annoying to maintain, but my
personal OCD won't allow it to be on my watch. Please fix the above
three lists.
I will fix it on v3.
Kind of related... has ever been discussed a naming convention for kvm
selftests? It would allow the use of regex on both .gitignore and
Makefile...and bye-bye those sorted lists.
TEST_GEN_PROGS_s390x = s390x/memop
TEST_GEN_PROGS_s390x += s390x/resets
@@ -46,6 +48,7 @@ TEST_GEN_PROGS_s390x += s390x/sync_regs_test
TEST_GEN_PROGS_s390x += demand_paging_test
TEST_GEN_PROGS_s390x += dirty_log_test
TEST_GEN_PROGS_s390x += kvm_create_max_vcpus
+TEST_GEN_PROGS_s390x += mem_slot_test
TEST_GEN_PROGS += $(TEST_GEN_PROGS_$(UNAME_M))
LIBKVM += $(LIBKVM_$(UNAME_M))
diff --git a/tools/testing/selftests/kvm/mem_slot_test.c b/tools/testing/selftests/kvm/mem_slot_test.c
new file mode 100644
index 000000000000..eef6f506f41d
--- /dev/null
+++ b/tools/testing/selftests/kvm/mem_slot_test.c
@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * mem_slot_test
+ *
+ * Copyright (C) 2020, Red Hat, Inc.
+ *
+ * Test suite for memory region operations.
+ */
+#define _GNU_SOURCE /* for program_invocation_short_name */
+#include <linux/kvm.h>
+#include <sys/mman.h>
+
+#include "test_util.h"
+#include "kvm_util.h"
+
+/*
+ * Test it can be added memory slots up to KVM_CAP_NR_MEMSLOTS, then any
+ * tentative to add further slots should fail.
+ */
+static void test_add_max_slots(void)
+{
+ struct kvm_vm *vm;
+ uint32_t max_mem_slots;
+ uint32_t slot;
+ uint64_t mem_reg_npages;
+ uint64_t mem_reg_size;
+ uint32_t mem_reg_flags;
+ uint64_t guest_addr;
+ int ret;
+
+ max_mem_slots = kvm_check_cap(KVM_CAP_NR_MEMSLOTS);
+ TEST_ASSERT(max_mem_slots > 0,
+ "KVM_CAP_NR_MEMSLOTS should be greater than 0");
+ pr_info("Allowed number of memory slots: %i\n", max_mem_slots);
+
+ vm = vm_create(VM_MODE_DEFAULT, 0, O_RDWR);
+
+ /*
+ * Uses 1MB sized/aligned memory region since this is the minimal
+ * required on s390x.
+ */
+ mem_reg_size = 0x100000;
+ mem_reg_npages = vm_calc_num_guest_pages(VM_MODE_DEFAULT, mem_reg_size);
+
+ mem_reg_flags = kvm_check_cap(KVM_CAP_READONLY_MEM) ? KVM_MEM_READONLY :
+ KVM_MEM_LOG_DIRTY_PAGES;
I still don't see why we're setting a flag at all, and now we're setting
different flags depending on what's available, so the test isn't the
same for every environment. I would just have mem->flags = 0 for this
test.
I thought I had to set a memory flag always. If mem->flags = 0 works
across the arches, then I change this on v3.
+
+ guest_addr = 0x0;
+
+ /* Check it can be added memory slots up to the maximum allowed */
+ pr_info("Adding slots 0..%i, each memory region with %ldK size\n",
+ (max_mem_slots - 1), mem_reg_size >> 10);
+ for (slot = 0; slot < max_mem_slots; slot++) {
+ vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
+ guest_addr, slot, mem_reg_npages,
+ mem_reg_flags);
+ guest_addr += mem_reg_size;
+ }
+
+ /* Check it cannot be added memory slots beyond the limit */
+ void *mem = mmap(NULL, mem_reg_size, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ TEST_ASSERT(mem != NULL, "Failed to mmap() host");
This should be testing mem != MAP_FAILED
Ok.
+
+ struct kvm_userspace_memory_region kvm_region = {
+ .slot = slot,
+ .flags = mem_reg_flags,
+ .guest_phys_addr = guest_addr,
+ .memory_size = mem_reg_size,
+ .userspace_addr = (uint64_t) mem,
+ };
Declaring kvm_region in the middle of the block. I don't really care
myself, but it's inconsistent with all the other variables which are
declared at the top.
Makes sense.
+
+ ret = ioctl(vm_get_fd(vm), KVM_SET_USER_MEMORY_REGION, &kvm_region);
+ TEST_ASSERT(ret == -1, "Adding one more memory slot should fail");
+ TEST_ASSERT(errno == EINVAL, "Should return EINVAL errno");
Please make the second assert message more specific. Or better would be
to combine the asserts
TEST_ASSERT(ret == -1 && errno == EINVAL, "Adding one more memory slot should fail with EINVAL");
Yeah, I was unsure about and'ing the checks. I will change it on v3.
Thanks!
Wainer
+
+ munmap(mem, mem_reg_size);
+ kvm_vm_free(vm);
+}
+
+int main(int argc, char *argv[])
+{
+ test_add_max_slots();
+ return 0;
+}
--
2.17.2
Thanks,
drew