On Mon, Mar 21, 2022 at 04:48:39PM -0700, Ben Gardon wrote: > There's currently no test coverage of NX hugepages in KVM selftests, so > add a basic test to ensure that the feature works as intended. > > Reviewed-by: David Dunn <daviddunn@xxxxxxxxxx> > > Signed-off-by: Ben Gardon <bgardon@xxxxxxxxxx> > --- > tools/testing/selftests/kvm/Makefile | 3 +- > .../kvm/lib/x86_64/nx_huge_pages_guest.S | 45 ++++++ > .../selftests/kvm/x86_64/nx_huge_pages_test.c | 133 ++++++++++++++++++ > .../kvm/x86_64/nx_huge_pages_test.sh | 25 ++++ > 4 files changed, 205 insertions(+), 1 deletion(-) > create mode 100644 tools/testing/selftests/kvm/lib/x86_64/nx_huge_pages_guest.S > create mode 100644 tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.c > create mode 100755 tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.sh > > diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile > index 04099f453b59..6ee30c0df323 100644 > --- a/tools/testing/selftests/kvm/Makefile > +++ b/tools/testing/selftests/kvm/Makefile > @@ -38,7 +38,7 @@ ifeq ($(ARCH),riscv) > endif > > LIBKVM = lib/assert.c lib/elf.c lib/io.c lib/kvm_util.c lib/rbtree.c lib/sparsebit.c lib/test_util.c lib/guest_modes.c lib/perf_test_util.c > -LIBKVM_x86_64 = lib/x86_64/apic.c lib/x86_64/processor.c lib/x86_64/vmx.c lib/x86_64/svm.c lib/x86_64/ucall.c lib/x86_64/handlers.S > +LIBKVM_x86_64 = lib/x86_64/apic.c lib/x86_64/processor.c lib/x86_64/vmx.c lib/x86_64/svm.c lib/x86_64/ucall.c lib/x86_64/handlers.S lib/x86_64/nx_huge_pages_guest.S > LIBKVM_aarch64 = lib/aarch64/processor.c lib/aarch64/ucall.c lib/aarch64/handlers.S lib/aarch64/spinlock.c lib/aarch64/gic.c lib/aarch64/gic_v3.c lib/aarch64/vgic.c > LIBKVM_s390x = lib/s390x/processor.c lib/s390x/ucall.c lib/s390x/diag318_test_handler.c > LIBKVM_riscv = lib/riscv/processor.c lib/riscv/ucall.c > @@ -56,6 +56,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/kvm_clock_test > TEST_GEN_PROGS_x86_64 += x86_64/kvm_pv_test > TEST_GEN_PROGS_x86_64 += x86_64/mmio_warning_test > TEST_GEN_PROGS_x86_64 += x86_64/mmu_role_test > +TEST_GEN_PROGS_x86_64 += x86_64/nx_huge_pages_test This will make the selftest infrastructure treat nx_huge_pages_test as the selftest that gets run by default (e.g. if someone runs `make kselftest`). But you actually want nx_huge_pages_test.sh to be the selftest that gets run (nx_huge_pages_test is really just a helper binary). Is that correct? Take a look at [1] for how to set this up. Specifically I think you want to move nx_huge_pages_test to TEST_GEN_PROGS_EXTENDED and add nx_huge_pages_test.sh to TEST_PROGS. I'd love to have the infrastructure in place for doing this because I've been wanting to add some shell script wrappers for dirty_log_perf_test to set up HugeTLBFS and invoke it with various different arguments. [1] https://www.kernel.org/doc/html/latest/dev-tools/kselftest.html#contributing-new-tests-details > TEST_GEN_PROGS_x86_64 += x86_64/platform_info_test > TEST_GEN_PROGS_x86_64 += x86_64/pmu_event_filter_test > TEST_GEN_PROGS_x86_64 += x86_64/set_boot_cpu_id > diff --git a/tools/testing/selftests/kvm/lib/x86_64/nx_huge_pages_guest.S b/tools/testing/selftests/kvm/lib/x86_64/nx_huge_pages_guest.S > new file mode 100644 > index 000000000000..09c66b9562a3 > --- /dev/null > +++ b/tools/testing/selftests/kvm/lib/x86_64/nx_huge_pages_guest.S > @@ -0,0 +1,45 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * tools/testing/selftests/kvm/nx_huge_page_guest.S > + * > + * Copyright (C) 2022, Google LLC. > + */ > + > +.include "kvm_util.h" > + > +#define HPAGE_SIZE (2*1024*1024) > +#define PORT_SUCCESS 0x70 > + > +.global guest_code0 > +.global guest_code1 > + > +.align HPAGE_SIZE > +exit_vm: > + mov $0x1,%edi > + mov $0x2,%esi > + mov a_string,%edx > + mov $0x1,%ecx > + xor %eax,%eax > + jmp ucall > + > + > +guest_code0: > + mov data1, %eax > + mov data2, %eax > + jmp exit_vm > + > +.align HPAGE_SIZE > +guest_code1: > + mov data1, %eax > + mov data2, %eax > + jmp exit_vm > +data1: > +.quad 0 > + > +.align HPAGE_SIZE > +data2: > +.quad 0 > +a_string: > +.string "why does the ucall function take a string argument?" > + > + > diff --git a/tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.c b/tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.c > new file mode 100644 > index 000000000000..2bcbe4efdc6a > --- /dev/null > +++ b/tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.c > @@ -0,0 +1,133 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * tools/testing/selftests/kvm/nx_huge_page_test.c > + * > + * Usage: to be run via nx_huge_page_test.sh, which does the necessary > + * environment setup and teardown > + * > + * Copyright (C) 2022, Google LLC. > + */ > + > +#define _GNU_SOURCE > + > +#include <fcntl.h> > +#include <stdint.h> > +#include <time.h> > + > +#include <test_util.h> > +#include "kvm_util.h" > + > +#define HPAGE_SLOT 10 > +#define HPAGE_PADDR_START (10*1024*1024) > +#define HPAGE_SLOT_NPAGES (100*1024*1024/4096) > + > +/* Defined in nx_huge_page_guest.S */ > +void guest_code0(void); > +void guest_code1(void); > + > +static void run_guest_code(struct kvm_vm *vm, void (*guest_code)(void)) > +{ > + struct kvm_regs regs; > + > + vcpu_regs_get(vm, 0, ®s); > + regs.rip = (uint64_t)guest_code; > + vcpu_regs_set(vm, 0, ®s); > + vcpu_run(vm, 0); > +} > + > +static void check_2m_page_count(struct kvm_vm *vm, int expected_pages_2m) > +{ > + int actual_pages_2m; > + > + actual_pages_2m = vm_get_single_stat(vm, "pages_2m"); > + > + TEST_ASSERT(actual_pages_2m == expected_pages_2m, > + "Unexpected 2m page count. Expected %d, got %d", > + expected_pages_2m, actual_pages_2m); > +} > + > +static void check_split_count(struct kvm_vm *vm, int expected_splits) > +{ > + int actual_splits; > + > + actual_splits = vm_get_single_stat(vm, "nx_lpage_splits"); > + > + TEST_ASSERT(actual_splits == expected_splits, > + "Unexpected nx lpage split count. Expected %d, got %d", > + expected_splits, actual_splits); > +} > + > +int main(int argc, char **argv) > +{ > + struct kvm_vm *vm; > + struct timespec ts; > + > + vm = vm_create(VM_MODE_DEFAULT, DEFAULT_GUEST_PHY_PAGES, O_RDWR); > + > + vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS_HUGETLB, > + HPAGE_PADDR_START, HPAGE_SLOT, > + HPAGE_SLOT_NPAGES, 0); > + > + kvm_vm_elf_load_memslot(vm, program_invocation_name, HPAGE_SLOT); > + > + vm_vcpu_add_default(vm, 0, guest_code0); > + > + check_2m_page_count(vm, 0); > + check_split_count(vm, 0); > + > + /* > + * Running guest_code0 will access data1 and data2. > + * This should result in part of the huge page containing guest_code0, > + * and part of the hugepage containing the ucall function being mapped > + * at 4K. The huge pages containing data1 and data2 will be mapped > + * at 2M. > + */ > + run_guest_code(vm, guest_code0); > + check_2m_page_count(vm, 2); > + check_split_count(vm, 2); > + > + /* > + * guest_code1 is in the same huge page as data1, so it will cause > + * that huge page to be remapped at 4k. > + */ > + run_guest_code(vm, guest_code1); > + check_2m_page_count(vm, 1); > + check_split_count(vm, 3); > + > + /* Run guest_code0 again to check that is has no effect. */ > + run_guest_code(vm, guest_code0); > + check_2m_page_count(vm, 1); > + check_split_count(vm, 3); > + > + /* > + * Give recovery thread time to run. The wrapper script sets > + * recovery_period_ms to 100, so wait 1.5x that. > + */ > + ts.tv_sec = 0; > + ts.tv_nsec = 150000000; > + nanosleep(&ts, NULL); > + > + /* > + * Now that the reclaimer has run, all the split pages should be gone. > + */ > + check_2m_page_count(vm, 1); > + check_split_count(vm, 0); > + > + /* > + * The split 2M pages should have been reclaimed, so run guest_code0 > + * again to check that pages are mapped at 2M again. > + */ > + run_guest_code(vm, guest_code0); > + check_2m_page_count(vm, 2); > + check_split_count(vm, 2); > + > + /* Pages are once again split from running guest_code1. */ > + run_guest_code(vm, guest_code1); > + check_2m_page_count(vm, 1); > + check_split_count(vm, 3); > + > + kvm_vm_free(vm); > + > + return 0; > +} > + > diff --git a/tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.sh b/tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.sh > new file mode 100755 > index 000000000000..19fc95723fcb > --- /dev/null > +++ b/tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.sh > @@ -0,0 +1,25 @@ > +#!/bin/bash > +# SPDX-License-Identifier: GPL-2.0-only */ > + > +# tools/testing/selftests/kvm/nx_huge_page_test.sh > +# Copyright (C) 2022, Google LLC. > + > +NX_HUGE_PAGES=$(cat /sys/module/kvm/parameters/nx_huge_pages) > +NX_HUGE_PAGES_RECOVERY_RATIO=$(cat /sys/module/kvm/parameters/nx_huge_pages_recovery_ratio) > +NX_HUGE_PAGES_RECOVERY_PERIOD=$(cat /sys/module/kvm/parameters/nx_huge_pages_recovery_period_ms) > +HUGE_PAGES=$(cat /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages) > + > +echo 1 > /sys/module/kvm/parameters/nx_huge_pages > +echo 1 > /sys/module/kvm/parameters/nx_huge_pages_recovery_ratio > +echo 100 > /sys/module/kvm/parameters/nx_huge_pages_recovery_period_ms > +echo 200 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages > + > +./nx_huge_pages_test > +RET=$? > + > +echo $NX_HUGE_PAGES > /sys/module/kvm/parameters/nx_huge_pages > +echo $NX_HUGE_PAGES_RECOVERY_RATIO > /sys/module/kvm/parameters/nx_huge_pages_recovery_ratio > +echo $NX_HUGE_PAGES_RECOVERY_PERIOD > /sys/module/kvm/parameters/nx_huge_pages_recovery_period_ms > +echo $HUGE_PAGES > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages > + > +exit $RET > -- > 2.35.1.894.gb6a874cedc-goog >
