selftests: kvm: Add support for customized slot0 memory size

Until commit 39fe2fc96694 ("selftests: kvm: make allocation of extra
memory take effect", 2021-05-27), parameter extra_mem_pages was used
only to calculate the page table size for all the memory chunks,
because real memory allocation happened with calls of
vm_userspace_mem_region_add() after vm_create_default().

Commit 39fe2fc96694 however changed the meaning of extra_mem_pages to
the size of memory slot 0.  This makes the memory allocation more
flexible, but makes it harder to account for the number of
pages needed for the page tables.  For example, memslot_perf_test
has a small amount of memory in slot 0 but a lot in other slots,
and adding that memory twice (both in slot 0 and with later
calls to vm_userspace_mem_region_add()) causes an error that
was fixed in commit 000ac4295339 ("selftests: kvm: fix overlapping
addresses in memslot_perf_test", 2021-05-29)

Since both uses are sensible, add a new parameter slot0_mem_pages
to vm_create_with_vcpus() and some comments to clarify the meaning of
slot0_mem_pages and extra_mem_pages.  With this change,
memslot_perf_test can go back to passing the number of memory
pages as extra_mem_pages.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Message-Id: <20210608233816.423958-4-zhenzhong.duan@intel.com>
[Squashed in a single patch and rewrote the commit message. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index b602552b1ed0981e647698aa40e94ba9030faf90..35739567189e09d8ad9533440d965e8592d70a9d 100644 (file)
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -286,10 +286,11 @@ struct kvm_vm *vm_create_default_with_vcpus(uint32_t nr_vcpus, uint64_t extra_me
                                            uint32_t num_percpu_pages, void *guest_code,
                                            uint32_t vcpuids[]);
 
-/* Like vm_create_default_with_vcpus, but accepts mode as a parameter */
+/* Like vm_create_default_with_vcpus, but accepts mode and slot0 memory as a parameter */
 struct kvm_vm *vm_create_with_vcpus(enum vm_guest_mode mode, uint32_t nr_vcpus,
-                                   uint64_t extra_mem_pages, uint32_t num_percpu_pages,
-                                   void *guest_code, uint32_t vcpuids[]);
+                                   uint64_t slot0_mem_pages, uint64_t extra_mem_pages,
+                                   uint32_t num_percpu_pages, void *guest_code,
+                                   uint32_t vcpuids[]);
 
 /*
  * Adds a vCPU with reasonable defaults (e.g. a stack)

diff --git a/tools/testing/selftests/kvm/kvm_page_table_test.c b/tools/testing/selftests/kvm/kvm_page_table_test.c
index 1c4753fff19e00a0e45a3c02e45a5ed30e451a9c..82171f17c1d7f4416667688b5c12a8466a9b9346 100644 (file)
--- a/tools/testing/selftests/kvm/kvm_page_table_test.c
+++ b/tools/testing/selftests/kvm/kvm_page_table_test.c
@@ -268,7 +268,7 @@ static struct kvm_vm *pre_init_before_test(enum vm_guest_mode mode, void *arg)
 
        /* Create a VM with enough guest pages */
        guest_num_pages = test_mem_size / guest_page_size;
-       vm = vm_create_with_vcpus(mode, nr_vcpus,
+       vm = vm_create_with_vcpus(mode, nr_vcpus, DEFAULT_GUEST_PHY_PAGES,
                                  guest_num_pages, 0, guest_code, NULL);
 
        /* Align down GPA of the testing memslot */

diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index b126fab6c4e1e7771be249aa15304ff5fb59a37e..5c70596dd1b9883421e9dfc03c8f1813c4bc940e 100644 (file)
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -313,21 +313,50 @@ struct kvm_vm *vm_create(enum vm_guest_mode mode, uint64_t phy_pages, int perm)
        return vm;
 }
 
+/*
+ * VM Create with customized parameters
+ *
+ * Input Args:
+ *   mode - VM Mode (e.g. VM_MODE_P52V48_4K)
+ *   nr_vcpus - VCPU count
+ *   slot0_mem_pages - Slot0 physical memory size
+ *   extra_mem_pages - Non-slot0 physical memory total size
+ *   num_percpu_pages - Per-cpu physical memory pages
+ *   guest_code - Guest entry point
+ *   vcpuids - VCPU IDs
+ *
+ * Output Args: None
+ *
+ * Return:
+ *   Pointer to opaque structure that describes the created VM.
+ *
+ * Creates a VM with the mode specified by mode (e.g. VM_MODE_P52V48_4K),
+ * with customized slot0 memory size, at least 512 pages currently.
+ * extra_mem_pages is only used to calculate the maximum page table size,
+ * no real memory allocation for non-slot0 memory in this function.
+ */
 struct kvm_vm *vm_create_with_vcpus(enum vm_guest_mode mode, uint32_t nr_vcpus,
-                                   uint64_t extra_mem_pages, uint32_t num_percpu_pages,
-                                   void *guest_code, uint32_t vcpuids[])
+                                   uint64_t slot0_mem_pages, uint64_t extra_mem_pages,
+                                   uint32_t num_percpu_pages, void *guest_code,
+                                   uint32_t vcpuids[])
 {
+       uint64_t vcpu_pages, extra_pg_pages, pages;
+       struct kvm_vm *vm;
+       int i;
+
+       /* Force slot0 memory size not small than DEFAULT_GUEST_PHY_PAGES */
+       if (slot0_mem_pages < DEFAULT_GUEST_PHY_PAGES)
+               slot0_mem_pages = DEFAULT_GUEST_PHY_PAGES;
+
        /* The maximum page table size for a memory region will be when the
         * smallest pages are used. Considering each page contains x page
         * table descriptors, the total extra size for page tables (for extra
         * N pages) will be: N/x+N/x^2+N/x^3+... which is definitely smaller
         * than N/x*2.
         */
-       uint64_t vcpu_pages = (DEFAULT_STACK_PGS + num_percpu_pages) * nr_vcpus;
-       uint64_t extra_pg_pages = (extra_mem_pages + vcpu_pages) / PTES_PER_MIN_PAGE * 2;
-       uint64_t pages = DEFAULT_GUEST_PHY_PAGES + extra_mem_pages + vcpu_pages + extra_pg_pages;
-       struct kvm_vm *vm;
-       int i;
+       vcpu_pages = (DEFAULT_STACK_PGS + num_percpu_pages) * nr_vcpus;
+       extra_pg_pages = (slot0_mem_pages + extra_mem_pages + vcpu_pages) / PTES_PER_MIN_PAGE * 2;
+       pages = slot0_mem_pages + vcpu_pages + extra_pg_pages;
 
        TEST_ASSERT(nr_vcpus <= kvm_check_cap(KVM_CAP_MAX_VCPUS),
                    "nr_vcpus = %d too large for host, max-vcpus = %d",
@@ -359,8 +388,8 @@ struct kvm_vm *vm_create_default_with_vcpus(uint32_t nr_vcpus, uint64_t extra_me
                                            uint32_t num_percpu_pages, void *guest_code,
                                            uint32_t vcpuids[])
 {
-       return vm_create_with_vcpus(VM_MODE_DEFAULT, nr_vcpus, extra_mem_pages,
-                                   num_percpu_pages, guest_code, vcpuids);
+       return vm_create_with_vcpus(VM_MODE_DEFAULT, nr_vcpus, DEFAULT_GUEST_PHY_PAGES,
+                                   extra_mem_pages, num_percpu_pages, guest_code, vcpuids);
 }
 
 struct kvm_vm *vm_create_default(uint32_t vcpuid, uint64_t extra_mem_pages,

diff --git a/tools/testing/selftests/kvm/lib/perf_test_util.c b/tools/testing/selftests/kvm/lib/perf_test_util.c
index abf381800a5909726f5391feeece8bbea352c518..7397ca2998358c09d737d174039df78c3ba469f1 100644 (file)
--- a/tools/testing/selftests/kvm/lib/perf_test_util.c
+++ b/tools/testing/selftests/kvm/lib/perf_test_util.c
@@ -69,7 +69,7 @@ struct kvm_vm *perf_test_create_vm(enum vm_guest_mode mode, int vcpus,
        TEST_ASSERT(vcpu_memory_bytes % perf_test_args.guest_page_size == 0,
                    "Guest memory size is not guest page size aligned.");
 
-       vm = vm_create_with_vcpus(mode, vcpus,
+       vm = vm_create_with_vcpus(mode, vcpus, DEFAULT_GUEST_PHY_PAGES,
                                  (vcpus * vcpu_memory_bytes) / perf_test_args.guest_page_size,
                                  0, guest_code, NULL);
 

diff --git a/tools/testing/selftests/kvm/memslot_perf_test.c b/tools/testing/selftests/kvm/memslot_perf_test.c
index 9307f25d8130e158684c0815cdbd7f1df0a19047..11239652d80574b8ac7c37306f28e4ba6e4a12ab 100644 (file)
--- a/tools/testing/selftests/kvm/memslot_perf_test.c
+++ b/tools/testing/selftests/kvm/memslot_perf_test.c
@@ -267,7 +267,7 @@ static bool prepare_vm(struct vm_data *data, int nslots, uint64_t *maxslots,
        data->hva_slots = malloc(sizeof(*data->hva_slots) * data->nslots);
        TEST_ASSERT(data->hva_slots, "malloc() fail");
 
-       data->vm = vm_create_default(VCPU_ID, 1024, guest_code);
+       data->vm = vm_create_default(VCPU_ID, mempages, guest_code);
 
        pr_info_v("Adding slots 1..%i, each slot with %"PRIu64" pages + %"PRIu64" extra pages last\n",
                max_mem_slots - 1, data->pages_per_slot, rempages);