diff mbox series

[v2,06/11] KVM: selftests: Add NX huge pages test

Message ID 20220321234844.1543161-7-bgardon@google.com (mailing list archive)
State New, archived
Headers show
Series KVM: x86: Add a cap to disable NX hugepages on a VM | expand

Commit Message

Ben Gardon March 21, 2022, 11:48 p.m. UTC 
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@google.com>

Signed-off-by: Ben Gardon <bgardon@google.com>
---
 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

Comments

David Matlack March 28, 2022, 6:57 p.m. UTC | #1 
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@google.com>
> 
> Signed-off-by: Ben Gardon <bgardon@google.com>
> ---
>  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, &regs);
> +	regs.rip = (uint64_t)guest_code;
> +	vcpu_regs_set(vm, 0, &regs);
> +	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 $RET
> -- 
> 2.35.1.894.gb6a874cedc-goog
>
Ben Gardon March 28, 2022, 10:17 p.m. UTC | #2 
On Mon, Mar 28, 2022 at 11:57 AM David Matlack <dmatlack@google.com> wrote:
>
> On Mon, Mar 21, 2022 at 04:48:39PM -0700, Ben Gardon wrote:
> > There's currently no test coverage of NX hugepages in KVM selftests, so
> > add a basic test to ensure that the feature works as intended.
> >
> > Reviewed-by: David Dunn <daviddunn@google.com>
> >
> > Signed-off-by: Ben Gardon <bgardon@google.com>
> > ---
> >  tools/testing/selftests/kvm/Makefile          |   3 +-
> >  .../kvm/lib/x86_64/nx_huge_pages_guest.S      |  45 ++++++
> >  .../selftests/kvm/x86_64/nx_huge_pages_test.c | 133 ++++++++++++++++++
> >  .../kvm/x86_64/nx_huge_pages_test.sh          |  25 ++++
> >  4 files changed, 205 insertions(+), 1 deletion(-)
> >  create mode 100644 tools/testing/selftests/kvm/lib/x86_64/nx_huge_pages_guest.S
> >  create mode 100644 tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.c
> >  create mode 100755 tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.sh
> >
> > diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
> > index 04099f453b59..6ee30c0df323 100644
> > --- a/tools/testing/selftests/kvm/Makefile
> > +++ b/tools/testing/selftests/kvm/Makefile
> > @@ -38,7 +38,7 @@ ifeq ($(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

Oh awesome, thank you for the tip! I'll try that.

>
> >  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, &regs);
> > +     regs.rip = (uint64_t)guest_code;
> > +     vcpu_regs_set(vm, 0, &regs);
> > +     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
> >
diff mbox series

Patch

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
 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, &regs);
+	regs.rip = (uint64_t)guest_code;
+	vcpu_regs_set(vm, 0, &regs);
+	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