On Tue, Apr 5, 2022 at 3:38 PM David Matlack <dmatlack@xxxxxxxxxx> wrote: > > On Wed, Mar 30, 2022 at 10:46:16AM -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 | 7 +- > > .../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, 209 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 c9cdbd248727..c671224cf755 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 > > @@ -57,6 +57,8 @@ 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_EXTENDED_x86_64 += x86_64/nx_huge_pages_test > > +TEST_PROGS_x86_64 += x86_64/nx_huge_pages_test.sh > > Suggest brearking TEST_PROGS and TEST_GEN_PROGS_EXTENDED out into their > own separate blocks with newlines in between. They capture different > types of files so I think it makes sense to separate them in the > Makefile. I expect both lists will grow over time so the awkwardness of > having them off on their lonesome is temporary :). > > It'd also be nice to have some comments above each explaining when they > should be used. A short blurb is fine since the selftest documentation > is the authority. Will do. > > > 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 > > @@ -141,7 +143,9 @@ TEST_GEN_PROGS_riscv += kvm_page_table_test > > TEST_GEN_PROGS_riscv += set_memory_region_test > > TEST_GEN_PROGS_riscv += kvm_binary_stats_test > > > > +TEST_PROGS += $(TEST_PROGS_$(UNAME_M)) > > TEST_GEN_PROGS += $(TEST_GEN_PROGS_$(UNAME_M)) > > +TEST_GEN_PROGS_EXTENDED += $(TEST_GEN_PROGS_EXTENDED_$(UNAME_M)) > > LIBKVM += $(LIBKVM_$(UNAME_M)) > > > > INSTALL_HDR_PATH = $(top_srcdir)/usr > > @@ -192,6 +196,7 @@ $(OUTPUT)/libkvm.a: $(LIBKVM_OBJS) > > x := $(shell mkdir -p $(sort $(dir $(TEST_GEN_PROGS)))) > > all: $(STATIC_LIBS) > > $(TEST_GEN_PROGS): $(STATIC_LIBS) > > +$(TEST_GEN_PROGS_EXTENDED): $(STATIC_LIBS) > > > > cscope: include_paths = $(LINUX_TOOL_INCLUDE) $(LINUX_HDR_PATH) include lib .. > > cscope: > > 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 > > What do you think about my idea in [1] of using ret instructions and > function pointers to trigger execution on an arbitrary page? That would > avoid the need for this assembly file and we could probably share the > code between our tests. > > Feel free to take the idea and incorporate it directly if you agree, and > I'll rebase on top, since you're series is further along than mine. > > [1] https://lore.kernel.org/kvm/20220401233737.3021889-2-dmatlack@xxxxxxxxxx/ > Sigh, it means I have to rewrite a lot of the test, but it is the better way to write this test. > > + > > +.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. > > + */ > > So we give it an extra 50ms? That should probably be enough but I'm > paranoid so I'd probably bump it up to 500 ms. Will do. > > > + 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 > > -- > > 2.35.1.1021.g381101b075-goog > >
