Commit 4b5d12b0 authored by Ben Gardon's avatar Ben Gardon Committed by Paolo Bonzini
Browse files

KVM: selftests: Factor code out of demand_paging_test 



Much of the code in demand_paging_test can be reused by other, similar
multi-vCPU-memory-touching-perfromance-tests. Factor that common code
out for reuse.

No functional change expected.

This series was tested by running the following invocations on an Intel
Skylake machine:
dirty_log_perf_test -b 20m -i 100 -v 64
dirty_log_perf_test -b 20g -i 5 -v 4
dirty_log_perf_test -b 4g -i 5 -v 32
demand_paging_test -b 20m -v 64
demand_paging_test -b 20g -v 4
demand_paging_test -b 4g -v 32
All behaved as expected.

Signed-off-by: default avatarBen Gardon <bgardon@google.com>
Message-Id: <20201027233733.1484855-2-bgardon@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent afdb1960

tools/testing/selftests/kvm/demand_paging_test.c

+23 −181
Original line number Diff line number Diff line
@@ -21,18 +21,12 @@ 
#include <linux/bitops.h>

#include <linux/userfaultfd.h>



#include "test_util.h"

#include "kvm_util.h"

#include "perf_test_util.h"

#include "processor.h"

#include "test_util.h"



#ifdef __NR_userfaultfd



/* The memory slot index demand page */

#define TEST_MEM_SLOT_INDEX		1



/* Default guest test virtual memory offset */

#define DEFAULT_GUEST_TEST_MEM		0xc0000000



#define DEFAULT_GUEST_TEST_MEM_SIZE (1 << 30) /* 1G */



#ifdef PRINT_PER_PAGE_UPDATES
@@ -47,75 +41,14 @@ 
#define PER_VCPU_DEBUG(...) _no_printf(__VA_ARGS__)

#endif



#define MAX_VCPUS 512



/*

 * Guest/Host shared variables. Ensure addr_gva2hva() and/or

 * sync_global_to/from_guest() are used when accessing from

 * the host. READ/WRITE_ONCE() should also be used with anything

 * that may change.

 */

static uint64_t host_page_size;

static uint64_t guest_page_size;



static char *guest_data_prototype;



/*

 * Guest physical memory offset of the testing memory slot.

 * This will be set to the topmost valid physical address minus

 * the test memory size.

 */

static uint64_t guest_test_phys_mem;



/*

 * Guest virtual memory offset of the testing memory slot.

 * Must not conflict with identity mapped test code.

 */

static uint64_t guest_test_virt_mem = DEFAULT_GUEST_TEST_MEM;



struct vcpu_args {

	uint64_t gva;

	uint64_t pages;



	/* Only used by the host userspace part of the vCPU thread */

	int vcpu_id;

	struct kvm_vm *vm;

};



static struct vcpu_args vcpu_args[MAX_VCPUS];



/*

 * Continuously write to the first 8 bytes of each page in the demand paging

 * memory region.

 */

static void guest_code(uint32_t vcpu_id)

{

	uint64_t gva;

	uint64_t pages;

	int i;



	/* Make sure vCPU args data structure is not corrupt. */

	GUEST_ASSERT(vcpu_args[vcpu_id].vcpu_id == vcpu_id);



	gva = vcpu_args[vcpu_id].gva;

	pages = vcpu_args[vcpu_id].pages;



	for (i = 0; i < pages; i++) {

		uint64_t addr = gva + (i * guest_page_size);



		addr &= ~(host_page_size - 1);

		*(uint64_t *)addr = 0x0123456789ABCDEF;

	}



	GUEST_SYNC(1);

}



static void *vcpu_worker(void *data)

{

	int ret;

	struct vcpu_args *args = (struct vcpu_args *)data;

	struct kvm_vm *vm = args->vm;

	int vcpu_id = args->vcpu_id;

	struct vcpu_args *vcpu_args = (struct vcpu_args *)data;

	int vcpu_id = vcpu_args->vcpu_id;

	struct kvm_vm *vm = perf_test_args.vm;

	struct kvm_run *run;

	struct timespec start, end, ts_diff;
@@ -141,39 +74,6 @@ static void *vcpu_worker(void *data) 
	return NULL;

}



#define PAGE_SHIFT_4K  12

#define PTES_PER_4K_PT 512



static struct kvm_vm *create_vm(enum vm_guest_mode mode, int vcpus,

				uint64_t vcpu_memory_bytes)

{

	struct kvm_vm *vm;

	uint64_t pages = DEFAULT_GUEST_PHY_PAGES;



	/* Account for a few pages per-vCPU for stacks */

	pages += DEFAULT_STACK_PGS * vcpus;



	/*

	 * Reserve twice the ammount of memory needed to map the test region and

	 * the page table / stacks region, at 4k, for page tables. Do the

	 * calculation with 4K page size: the smallest of all archs. (e.g., 64K

	 * page size guest will need even less memory for page tables).

	 */

	pages += (2 * pages) / PTES_PER_4K_PT;

	pages += ((2 * vcpus * vcpu_memory_bytes) >> PAGE_SHIFT_4K) /

		 PTES_PER_4K_PT;

	pages = vm_adjust_num_guest_pages(mode, pages);



	pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode));



	vm = _vm_create(mode, pages, O_RDWR);

	kvm_vm_elf_load(vm, program_invocation_name, 0, 0);

#ifdef __x86_64__

	vm_create_irqchip(vm);

#endif

	return vm;

}



static int handle_uffd_page_request(int uffd, uint64_t addr)

{

	pid_t tid;
@@ -186,7 +86,7 @@ static int handle_uffd_page_request(int uffd, uint64_t addr) 


	copy.src = (uint64_t)guest_data_prototype;

	copy.dst = addr;

	copy.len = host_page_size;

	copy.len = perf_test_args.host_page_size;

	copy.mode = 0;



	clock_gettime(CLOCK_MONOTONIC, &start);
@@ -203,7 +103,7 @@ static int handle_uffd_page_request(int uffd, uint64_t addr) 
	PER_PAGE_DEBUG("UFFDIO_COPY %d \t%ld ns\n", tid,

		       timespec_to_ns(timespec_sub(end, start)));

	PER_PAGE_DEBUG("Paged in %ld bytes at 0x%lx from thread %d\n",

		       host_page_size, addr, tid);

		       perf_test_args.host_page_size, addr, tid);



	return 0;

}
@@ -360,64 +260,21 @@ static void run_test(enum vm_guest_mode mode, bool use_uffd, 
	struct timespec start, end, ts_diff;

	int *pipefds = NULL;

	struct kvm_vm *vm;

	uint64_t guest_num_pages;

	int vcpu_id;

	int r;



	vm = create_vm(mode, vcpus, vcpu_memory_bytes);



	guest_page_size = vm_get_page_size(vm);



	TEST_ASSERT(vcpu_memory_bytes % guest_page_size == 0,

		    "Guest memory size is not guest page size aligned.");



	guest_num_pages = (vcpus * vcpu_memory_bytes) / guest_page_size;

	guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages);



	/*

	 * If there should be more memory in the guest test region than there

	 * can be pages in the guest, it will definitely cause problems.

	 */

	TEST_ASSERT(guest_num_pages < vm_get_max_gfn(vm),

		    "Requested more guest memory than address space allows.\n"

		    "    guest pages: %lx max gfn: %x vcpus: %d wss: %lx]\n",

		    guest_num_pages, vm_get_max_gfn(vm), vcpus,

		    vcpu_memory_bytes);



	host_page_size = getpagesize();

	TEST_ASSERT(vcpu_memory_bytes % host_page_size == 0,

		    "Guest memory size is not host page size aligned.");



	guest_test_phys_mem = (vm_get_max_gfn(vm) - guest_num_pages) *

			      guest_page_size;

	guest_test_phys_mem &= ~(host_page_size - 1);



#ifdef __s390x__

	/* Align to 1M (segment size) */

	guest_test_phys_mem &= ~((1 << 20) - 1);

#endif



	pr_info("guest physical test memory offset: 0x%lx\n", guest_test_phys_mem);



	/* Add an extra memory slot for testing demand paging */

	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,

				    guest_test_phys_mem,

				    TEST_MEM_SLOT_INDEX,

				    guest_num_pages, 0);



	/* Do mapping for the demand paging memory slot */

	virt_map(vm, guest_test_virt_mem, guest_test_phys_mem, guest_num_pages, 0);



	ucall_init(vm, NULL);



	guest_data_prototype = malloc(host_page_size);

	guest_data_prototype = malloc(perf_test_args.host_page_size);

	TEST_ASSERT(guest_data_prototype,

		    "Failed to allocate buffer for guest data pattern");

	memset(guest_data_prototype, 0xAB, host_page_size);

	memset(guest_data_prototype, 0xAB, perf_test_args.host_page_size);



	vcpu_threads = malloc(vcpus * sizeof(*vcpu_threads));

	TEST_ASSERT(vcpu_threads, "Memory allocation failed");



	add_vcpus(vm, vcpus, vcpu_memory_bytes);



	if (use_uffd) {

		uffd_handler_threads =

			malloc(vcpus * sizeof(*uffd_handler_threads));
@@ -428,14 +285,11 @@ static void run_test(enum vm_guest_mode mode, bool use_uffd, 


		pipefds = malloc(sizeof(int) * vcpus * 2);

		TEST_ASSERT(pipefds, "Unable to allocate memory for pipefd");

	}



		for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {

			vm_paddr_t vcpu_gpa;

			void *vcpu_hva;



		vm_vcpu_add_default(vm, vcpu_id, guest_code);



			vcpu_gpa = guest_test_phys_mem + (vcpu_id * vcpu_memory_bytes);

			PER_VCPU_DEBUG("Added VCPU %d with test mem gpa [%lx, %lx)\n",

				       vcpu_id, vcpu_gpa, vcpu_gpa + vcpu_memory_bytes);
@@ -443,7 +297,6 @@ static void run_test(enum vm_guest_mode mode, bool use_uffd, 
			/* Cache the HVA pointer of the region */

			vcpu_hva = addr_gpa2hva(vm, vcpu_gpa);



		if (use_uffd) {

			/*

			 * Set up user fault fd to handle demand paging

			 * requests.
@@ -460,22 +313,10 @@ static void run_test(enum vm_guest_mode mode, bool use_uffd, 
			if (r < 0)

				exit(-r);

		}



#ifdef __x86_64__

		vcpu_set_cpuid(vm, vcpu_id, kvm_get_supported_cpuid());

#endif



		vcpu_args[vcpu_id].vm = vm;

		vcpu_args[vcpu_id].vcpu_id = vcpu_id;

		vcpu_args[vcpu_id].gva = guest_test_virt_mem +

					 (vcpu_id * vcpu_memory_bytes);

		vcpu_args[vcpu_id].pages = vcpu_memory_bytes / guest_page_size;

	}



	/* Export the shared variables to the guest */

	sync_global_to_guest(vm, host_page_size);

	sync_global_to_guest(vm, guest_page_size);

	sync_global_to_guest(vm, vcpu_args);

	sync_global_to_guest(vm, perf_test_args);



	pr_info("Finished creating vCPUs and starting uffd threads\n");
@@ -483,7 +324,7 @@ static void run_test(enum vm_guest_mode mode, bool use_uffd, 


	for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {

		pthread_create(&vcpu_threads[vcpu_id], NULL, vcpu_worker,

			       &vcpu_args[vcpu_id]);

			       &perf_test_args.vcpu_args[vcpu_id]);

	}



	pr_info("Started all vCPUs\n");
@@ -514,7 +355,8 @@ static void run_test(enum vm_guest_mode mode, bool use_uffd, 
	pr_info("Total guest execution time: %ld.%.9lds\n",

		ts_diff.tv_sec, ts_diff.tv_nsec);

	pr_info("Overall demand paging rate: %f pgs/sec\n",

		guest_num_pages / ((double)ts_diff.tv_sec + (double)ts_diff.tv_nsec / 100000000.0));

		perf_test_args.vcpu_args[0].pages * vcpus /

		((double)ts_diff.tv_sec + (double)ts_diff.tv_nsec / 100000000.0));



	ucall_uninit(vm);

	kvm_vm_free(vm);

tools/testing/selftests/kvm/include/perf_test_util.h

0 → 100644
+187 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * tools/testing/selftests/kvm/include/perf_test_util.h

 *

 * Copyright (C) 2020, Google LLC.

 */



#ifndef SELFTEST_KVM_PERF_TEST_UTIL_H

#define SELFTEST_KVM_PERF_TEST_UTIL_H



#include "kvm_util.h"

#include "processor.h"



#define MAX_VCPUS 512



#define PAGE_SHIFT_4K  12

#define PTES_PER_4K_PT 512



#define TEST_MEM_SLOT_INDEX		1



/* Default guest test virtual memory offset */

#define DEFAULT_GUEST_TEST_MEM		0xc0000000



/*

 * Guest physical memory offset of the testing memory slot.

 * This will be set to the topmost valid physical address minus

 * the test memory size.

 */

static uint64_t guest_test_phys_mem;



/*

 * Guest virtual memory offset of the testing memory slot.

 * Must not conflict with identity mapped test code.

 */

static uint64_t guest_test_virt_mem = DEFAULT_GUEST_TEST_MEM;



struct vcpu_args {

	uint64_t gva;

	uint64_t pages;



	/* Only used by the host userspace part of the vCPU thread */

	int vcpu_id;

};



struct perf_test_args {

	struct kvm_vm *vm;

	uint64_t host_page_size;

	uint64_t guest_page_size;



	struct vcpu_args vcpu_args[MAX_VCPUS];

};



static struct perf_test_args perf_test_args;



/*

 * Continuously write to the first 8 bytes of each page in the

 * specified region.

 */

static void guest_code(uint32_t vcpu_id)

{

	struct vcpu_args *vcpu_args = &perf_test_args.vcpu_args[vcpu_id];

	uint64_t gva;

	uint64_t pages;

	int i;



	/* Make sure vCPU args data structure is not corrupt. */

	GUEST_ASSERT(vcpu_args->vcpu_id == vcpu_id);



	gva = vcpu_args->gva;

	pages = vcpu_args->pages;



	for (i = 0; i < pages; i++) {

		uint64_t addr = gva + (i * perf_test_args.guest_page_size);



		addr &= ~(perf_test_args.host_page_size - 1);

		*(uint64_t *)addr = 0x0123456789ABCDEF;

	}



	GUEST_SYNC(1);

}



static struct kvm_vm *create_vm(enum vm_guest_mode mode, int vcpus,

				uint64_t vcpu_memory_bytes)

{

	struct kvm_vm *vm;

	uint64_t pages = DEFAULT_GUEST_PHY_PAGES;

	uint64_t guest_num_pages;



	/* Account for a few pages per-vCPU for stacks */

	pages += DEFAULT_STACK_PGS * vcpus;



	/*

	 * Reserve twice the ammount of memory needed to map the test region and

	 * the page table / stacks region, at 4k, for page tables. Do the

	 * calculation with 4K page size: the smallest of all archs. (e.g., 64K

	 * page size guest will need even less memory for page tables).

	 */

	pages += (2 * pages) / PTES_PER_4K_PT;

	pages += ((2 * vcpus * vcpu_memory_bytes) >> PAGE_SHIFT_4K) /

		 PTES_PER_4K_PT;

	pages = vm_adjust_num_guest_pages(mode, pages);



	pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode));



	vm = _vm_create(mode, pages, O_RDWR);

	kvm_vm_elf_load(vm, program_invocation_name, 0, 0);

#ifdef __x86_64__

	vm_create_irqchip(vm);

#endif



	perf_test_args.vm = vm;

	perf_test_args.guest_page_size = vm_get_page_size(vm);

	perf_test_args.host_page_size = getpagesize();



	TEST_ASSERT(vcpu_memory_bytes % perf_test_args.guest_page_size == 0,

		    "Guest memory size is not guest page size aligned.");



	guest_num_pages = (vcpus * vcpu_memory_bytes) /

			  perf_test_args.guest_page_size;

	guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages);



	/*

	 * If there should be more memory in the guest test region than there

	 * can be pages in the guest, it will definitely cause problems.

	 */

	TEST_ASSERT(guest_num_pages < vm_get_max_gfn(vm),

		    "Requested more guest memory than address space allows.\n"

		    "    guest pages: %lx max gfn: %x vcpus: %d wss: %lx]\n",

		    guest_num_pages, vm_get_max_gfn(vm), vcpus,

		    vcpu_memory_bytes);



	TEST_ASSERT(vcpu_memory_bytes % perf_test_args.host_page_size == 0,

		    "Guest memory size is not host page size aligned.");



	guest_test_phys_mem = (vm_get_max_gfn(vm) - guest_num_pages) *

			      perf_test_args.guest_page_size;

	guest_test_phys_mem &= ~(perf_test_args.host_page_size - 1);



#ifdef __s390x__

	/* Align to 1M (segment size) */

	guest_test_phys_mem &= ~((1 << 20) - 1);

#endif



	pr_info("guest physical test memory offset: 0x%lx\n", guest_test_phys_mem);



	/* Add an extra memory slot for testing */

	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,

				    guest_test_phys_mem,

				    TEST_MEM_SLOT_INDEX,

				    guest_num_pages, 0);



	/* Do mapping for the demand paging memory slot */

	virt_map(vm, guest_test_virt_mem, guest_test_phys_mem, guest_num_pages, 0);



	ucall_init(vm, NULL);



	return vm;

}



static void add_vcpus(struct kvm_vm *vm, int vcpus, uint64_t vcpu_memory_bytes)

{

	vm_paddr_t vcpu_gpa;

	struct vcpu_args *vcpu_args;

	int vcpu_id;



	for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {

		vcpu_args = &perf_test_args.vcpu_args[vcpu_id];



		vm_vcpu_add_default(vm, vcpu_id, guest_code);



#ifdef __x86_64__

		vcpu_set_cpuid(vm, vcpu_id, kvm_get_supported_cpuid());

#endif



		vcpu_args->vcpu_id = vcpu_id;

		vcpu_args->gva = guest_test_virt_mem +

				 (vcpu_id * vcpu_memory_bytes);

		vcpu_args->pages = vcpu_memory_bytes /

				   perf_test_args.guest_page_size;



		vcpu_gpa = guest_test_phys_mem + (vcpu_id * vcpu_memory_bytes);

		pr_debug("Added VCPU %d with test mem gpa [%lx, %lx)\n",

			 vcpu_id, vcpu_gpa, vcpu_gpa + vcpu_memory_bytes);

	}

}



#endif /* SELFTEST_KVM_PERF_TEST_UTIL_H */