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author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-08-04 14:59:54 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-08-04 14:59:54 -0700 |
commit | 7c5c3a6177fa9646884114fc7f2e970b0bc50dc9 (patch) | |
tree | 956857522574ae7cb07d2227dc16e53d7e9e00e7 /tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.c | |
parent | drm/amd/amdgpu: fix build failure due to implicit declaration (diff) | |
parent | selftests: kvm: set rax before vmcall (diff) | |
download | linux-dev-7c5c3a6177fa9646884114fc7f2e970b0bc50dc9.tar.xz linux-dev-7c5c3a6177fa9646884114fc7f2e970b0bc50dc9.zip |
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm updates from Paolo Bonzini:
"Quite a large pull request due to a selftest API overhaul and some
patches that had come in too late for 5.19.
ARM:
- Unwinder implementations for both nVHE modes (classic and
protected), complete with an overflow stack
- Rework of the sysreg access from userspace, with a complete rewrite
of the vgic-v3 view to allign with the rest of the infrastructure
- Disagregation of the vcpu flags in separate sets to better track
their use model.
- A fix for the GICv2-on-v3 selftest
- A small set of cosmetic fixes
RISC-V:
- Track ISA extensions used by Guest using bitmap
- Added system instruction emulation framework
- Added CSR emulation framework
- Added gfp_custom flag in struct kvm_mmu_memory_cache
- Added G-stage ioremap() and iounmap() functions
- Added support for Svpbmt inside Guest
s390:
- add an interface to provide a hypervisor dump for secure guests
- improve selftests to use TAP interface
- enable interpretive execution of zPCI instructions (for PCI
passthrough)
- First part of deferred teardown
- CPU Topology
- PV attestation
- Minor fixes
x86:
- Permit guests to ignore single-bit ECC errors
- Intel IPI virtualization
- Allow getting/setting pending triple fault with
KVM_GET/SET_VCPU_EVENTS
- PEBS virtualization
- Simplify PMU emulation by just using PERF_TYPE_RAW events
- More accurate event reinjection on SVM (avoid retrying
instructions)
- Allow getting/setting the state of the speaker port data bit
- Refuse starting the kvm-intel module if VM-Entry/VM-Exit controls
are inconsistent
- "Notify" VM exit (detect microarchitectural hangs) for Intel
- Use try_cmpxchg64 instead of cmpxchg64
- Ignore benign host accesses to PMU MSRs when PMU is disabled
- Allow disabling KVM's "MONITOR/MWAIT are NOPs!" behavior
- Allow NX huge page mitigation to be disabled on a per-vm basis
- Port eager page splitting to shadow MMU as well
- Enable CMCI capability by default and handle injected UCNA errors
- Expose pid of vcpu threads in debugfs
- x2AVIC support for AMD
- cleanup PIO emulation
- Fixes for LLDT/LTR emulation
- Don't require refcounted "struct page" to create huge SPTEs
- Miscellaneous cleanups:
- MCE MSR emulation
- Use separate namespaces for guest PTEs and shadow PTEs bitmasks
- PIO emulation
- Reorganize rmap API, mostly around rmap destruction
- Do not workaround very old KVM bugs for L0 that runs with nesting enabled
- new selftests API for CPUID
Generic:
- Fix races in gfn->pfn cache refresh; do not pin pages tracked by
the cache
- new selftests API using struct kvm_vcpu instead of a (vm, id)
tuple"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (606 commits)
selftests: kvm: set rax before vmcall
selftests: KVM: Add exponent check for boolean stats
selftests: KVM: Provide descriptive assertions in kvm_binary_stats_test
selftests: KVM: Check stat name before other fields
KVM: x86/mmu: remove unused variable
RISC-V: KVM: Add support for Svpbmt inside Guest/VM
RISC-V: KVM: Use PAGE_KERNEL_IO in kvm_riscv_gstage_ioremap()
RISC-V: KVM: Add G-stage ioremap() and iounmap() functions
KVM: Add gfp_custom flag in struct kvm_mmu_memory_cache
RISC-V: KVM: Add extensible CSR emulation framework
RISC-V: KVM: Add extensible system instruction emulation framework
RISC-V: KVM: Factor-out instruction emulation into separate sources
RISC-V: KVM: move preempt_disable() call in kvm_arch_vcpu_ioctl_run
RISC-V: KVM: Make kvm_riscv_guest_timer_init a void function
RISC-V: KVM: Fix variable spelling mistake
RISC-V: KVM: Improve ISA extension by using a bitmap
KVM, x86/mmu: Fix the comment around kvm_tdp_mmu_zap_leafs()
KVM: SVM: Dump Virtual Machine Save Area (VMSA) to klog
KVM: x86/mmu: Treat NX as a valid SPTE bit for NPT
KVM: x86: Do not block APIC write for non ICR registers
...
Diffstat (limited to 'tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.c')
-rw-r--r-- | tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.c | 269 |
1 files changed, 269 insertions, 0 deletions
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..cc6421716400 --- /dev/null +++ b/tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.c @@ -0,0 +1,269 @@ +// 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" +#include "processor.h" + +#define HPAGE_SLOT 10 +#define HPAGE_GPA (4UL << 30) /* 4G prevents collision w/ slot 0 */ +#define HPAGE_GVA HPAGE_GPA /* GVA is arbitrary, so use GPA. */ +#define PAGES_PER_2MB_HUGE_PAGE 512 +#define HPAGE_SLOT_NPAGES (3 * PAGES_PER_2MB_HUGE_PAGE) + +/* + * Passed by nx_huge_pages_test.sh to provide an easy warning if this test is + * being run without it. + */ +#define MAGIC_TOKEN 887563923 + +/* + * x86 opcode for the return instruction. Used to call into, and then + * immediately return from, memory backed with hugepages. + */ +#define RETURN_OPCODE 0xC3 + +/* Call the specified memory address. */ +static void guest_do_CALL(uint64_t target) +{ + ((void (*)(void)) target)(); +} + +/* + * Exit the VM after each memory access so that the userspace component of the + * test can make assertions about the pages backing the VM. + * + * See the below for an explanation of how each access should affect the + * backing mappings. + */ +void guest_code(void) +{ + uint64_t hpage_1 = HPAGE_GVA; + uint64_t hpage_2 = hpage_1 + (PAGE_SIZE * 512); + uint64_t hpage_3 = hpage_2 + (PAGE_SIZE * 512); + + READ_ONCE(*(uint64_t *)hpage_1); + GUEST_SYNC(1); + + READ_ONCE(*(uint64_t *)hpage_2); + GUEST_SYNC(2); + + guest_do_CALL(hpage_1); + GUEST_SYNC(3); + + guest_do_CALL(hpage_3); + GUEST_SYNC(4); + + READ_ONCE(*(uint64_t *)hpage_1); + GUEST_SYNC(5); + + READ_ONCE(*(uint64_t *)hpage_3); + GUEST_SYNC(6); +} + +static void check_2m_page_count(struct kvm_vm *vm, int expected_pages_2m) +{ + int actual_pages_2m; + + actual_pages_2m = vm_get_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_stat(vm, "nx_lpage_splits"); + + TEST_ASSERT(actual_splits == expected_splits, + "Unexpected NX huge page split count. Expected %d, got %d", + expected_splits, actual_splits); +} + +static void wait_for_reclaim(int reclaim_period_ms) +{ + long reclaim_wait_ms; + struct timespec ts; + + reclaim_wait_ms = reclaim_period_ms * 5; + ts.tv_sec = reclaim_wait_ms / 1000; + ts.tv_nsec = (reclaim_wait_ms - (ts.tv_sec * 1000)) * 1000000; + nanosleep(&ts, NULL); +} + +void run_test(int reclaim_period_ms, bool disable_nx_huge_pages, + bool reboot_permissions) +{ + struct kvm_vcpu *vcpu; + struct kvm_vm *vm; + void *hva; + int r; + + vm = vm_create(1); + + if (disable_nx_huge_pages) { + /* + * Cannot run the test without NX huge pages if the kernel + * does not support it. + */ + if (!kvm_check_cap(KVM_CAP_VM_DISABLE_NX_HUGE_PAGES)) + return; + + r = __vm_disable_nx_huge_pages(vm); + if (reboot_permissions) { + TEST_ASSERT(!r, "Disabling NX huge pages should succeed if process has reboot permissions"); + } else { + TEST_ASSERT(r == -1 && errno == EPERM, + "This process should not have permission to disable NX huge pages"); + return; + } + } + + vcpu = vm_vcpu_add(vm, 0, guest_code); + + vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS_HUGETLB, + HPAGE_GPA, HPAGE_SLOT, + HPAGE_SLOT_NPAGES, 0); + + virt_map(vm, HPAGE_GVA, HPAGE_GPA, HPAGE_SLOT_NPAGES); + + hva = addr_gpa2hva(vm, HPAGE_GPA); + memset(hva, RETURN_OPCODE, HPAGE_SLOT_NPAGES * PAGE_SIZE); + + check_2m_page_count(vm, 0); + check_split_count(vm, 0); + + /* + * The guest code will first read from the first hugepage, resulting + * in a huge page mapping being created. + */ + vcpu_run(vcpu); + check_2m_page_count(vm, 1); + check_split_count(vm, 0); + + /* + * Then the guest code will read from the second hugepage, resulting + * in another huge page mapping being created. + */ + vcpu_run(vcpu); + check_2m_page_count(vm, 2); + check_split_count(vm, 0); + + /* + * Next, the guest will execute from the first huge page, causing it + * to be remapped at 4k. + * + * If NX huge pages are disabled, this should have no effect. + */ + vcpu_run(vcpu); + check_2m_page_count(vm, disable_nx_huge_pages ? 2 : 1); + check_split_count(vm, disable_nx_huge_pages ? 0 : 1); + + /* + * Executing from the third huge page (previously unaccessed) will + * cause part to be mapped at 4k. + * + * If NX huge pages are disabled, it should be mapped at 2M. + */ + vcpu_run(vcpu); + check_2m_page_count(vm, disable_nx_huge_pages ? 3 : 1); + check_split_count(vm, disable_nx_huge_pages ? 0 : 2); + + /* Reading from the first huge page again should have no effect. */ + vcpu_run(vcpu); + check_2m_page_count(vm, disable_nx_huge_pages ? 3 : 1); + check_split_count(vm, disable_nx_huge_pages ? 0 : 2); + + /* Give recovery thread time to run. */ + wait_for_reclaim(reclaim_period_ms); + + /* + * Now that the reclaimer has run, all the split pages should be gone. + * + * If NX huge pages are disabled, the relaimer will not run, so + * nothing should change from here on. + */ + check_2m_page_count(vm, disable_nx_huge_pages ? 3 : 1); + check_split_count(vm, 0); + + /* + * The 4k mapping on hpage 3 should have been removed, so check that + * reading from it causes a huge page mapping to be installed. + */ + vcpu_run(vcpu); + check_2m_page_count(vm, disable_nx_huge_pages ? 3 : 2); + check_split_count(vm, 0); + + kvm_vm_free(vm); +} + +static void help(char *name) +{ + puts(""); + printf("usage: %s [-h] [-p period_ms] [-t token]\n", name); + puts(""); + printf(" -p: The NX reclaim period in miliseconds.\n"); + printf(" -t: The magic token to indicate environment setup is done.\n"); + printf(" -r: The test has reboot permissions and can disable NX huge pages.\n"); + puts(""); + exit(0); +} + +int main(int argc, char **argv) +{ + int reclaim_period_ms = 0, token = 0, opt; + bool reboot_permissions = false; + + while ((opt = getopt(argc, argv, "hp:t:r")) != -1) { + switch (opt) { + case 'p': + reclaim_period_ms = atoi(optarg); + break; + case 't': + token = atoi(optarg); + break; + case 'r': + reboot_permissions = true; + break; + case 'h': + default: + help(argv[0]); + break; + } + } + + if (token != MAGIC_TOKEN) { + print_skip("This test must be run with the magic token %d.\n" + "This is done by nx_huge_pages_test.sh, which\n" + "also handles environment setup for the test.", + MAGIC_TOKEN); + exit(KSFT_SKIP); + } + + if (!reclaim_period_ms) { + print_skip("The NX reclaim period must be specified and non-zero"); + exit(KSFT_SKIP); + } + + run_test(reclaim_period_ms, false, reboot_permissions); + run_test(reclaim_period_ms, true, reboot_permissions); + + return 0; +} + |