[PATCH v7 09/11] KVM: selftests: Factor out calculation of pages needed for a VM

Ben Gardon
2022-05-03T18:31:34Z

Factor out the calculation of the number of pages needed for a VM to
make it easier to separate creating the VM and adding vCPUs.

Reviewed-by: David Matlack <dmatlack@google.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Ben Gardon <bgardon@google.com>
---
.../selftests/kvm/include/kvm_util_base.h | 4 ++
tools/testing/selftests/kvm/lib/kvm_util.c | 59 ++++++++++++++-----
2 files changed, 47 insertions(+), 16 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
index 001b55ae25f8..1dac3c6607f1 100644
--- a/tools/testing/selftests/kvm/include/kvm_util_base.h
+++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
@@ -312,6 +312,10 @@ vm_paddr_t vm_phy_pages_alloc(struct kvm_vm *vm, size_t num,
vm_paddr_t paddr_min, uint32_t memslot);
vm_paddr_t vm_alloc_page_table(struct kvm_vm *vm);

+uint64_t vm_pages_needed(enum vm_guest_mode mode, uint32_t nr_vcpus,
+ uint64_t slot0_mem_pages, uint64_t extra_mem_pages,
+ uint32_t num_percpu_pages);
+
/*
* Create a VM with reasonable defaults
*
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 6930ba298170..27ffd2537df6 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -377,7 +377,7 @@ struct kvm_vm *vm_create_without_vcpus(enum vm_guest_mode mode, uint64_t pages)
}

/*
- * VM Create with customized parameters
+ * Get the number of pages needed for a VM
*
* Input Args:
* mode - VM Mode (e.g. VM_MODE_P52V48_4K)
@@ -385,27 +385,17 @@ struct kvm_vm *vm_create_without_vcpus(enum vm_guest_mode mode, uint64_t pages)
* 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.
+ * The number of pages needed for the VM.
*/
-struct kvm_vm *vm_create_with_vcpus(enum vm_guest_mode mode, uint32_t nr_vcpus,
- uint64_t slot0_mem_pages, uint64_t extra_mem_pages,
- uint32_t num_percpu_pages, void *guest_code,
- uint32_t vcpuids[])
+uint64_t vm_pages_needed(enum vm_guest_mode mode, uint32_t nr_vcpus,
+ uint64_t slot0_mem_pages, uint64_t extra_mem_pages,
+ uint32_t num_percpu_pages)
{
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)
@@ -421,11 +411,48 @@ struct kvm_vm *vm_create_with_vcpus(enum vm_guest_mode mode, uint32_t 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;

+ pages = vm_adjust_num_guest_pages(mode, pages);
+
+ return pages;
+}
+
+/*
+ * 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 slot0_mem_pages, uint64_t extra_mem_pages,
+ uint32_t num_percpu_pages, void *guest_code,
+ uint32_t vcpuids[])
+{
+ uint64_t pages;
+ struct kvm_vm *vm;
+ int i;
+
TEST_ASSERT(nr_vcpus <= kvm_check_cap(KVM_CAP_MAX_VCPUS),
"nr_vcpus = %d too large for host, max-vcpus = %d",
nr_vcpus, kvm_check_cap(KVM_CAP_MAX_VCPUS));

- pages = vm_adjust_num_guest_pages(mode, pages);
+ pages = vm_pages_needed(mode, nr_vcpus, slot0_mem_pages,
+ extra_mem_pages, num_percpu_pages);

vm = vm_create_without_vcpus(mode, pages);

--
2.36.0.464.gb9c8b46e94-goog