From 0b9775016671f7e873a368d30597964e9b094741 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 14 Jun 2022 20:06:38 +0000 Subject: [PATCH] KVM: selftests: Remove the obsolete/dead MMU role test Remove the MMU role test, which was made obsolete by KVM commit e49d1db7e0d0 ("KVM: x86: Forbid KVM_SET_CPUID{,2} after KVM_RUN"). The ongoing costs of keeping the test updated far outweigh any benefits, e.g. the test _might_ be useful as an example or for documentation purposes, but otherwise the test is dead weight. Signed-off-by: Sean Christopherson Link: https://lore.kernel.org/r/20220614200707.3315957-14-seanjc@google.com --- tools/testing/selftests/kvm/.gitignore | 1 - tools/testing/selftests/kvm/Makefile | 1 - .../selftests/kvm/include/x86_64/processor.h | 3 - .../selftests/kvm/x86_64/mmu_role_test.c | 137 ------------------ 4 files changed, 142 deletions(-) delete mode 100644 tools/testing/selftests/kvm/x86_64/mmu_role_test.c diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore index f44ebf4013101..91429330faea0 100644 --- a/tools/testing/selftests/kvm/.gitignore +++ b/tools/testing/selftests/kvm/.gitignore @@ -27,7 +27,6 @@ /x86_64/hyperv_svm_test /x86_64/max_vcpuid_cap_test /x86_64/mmio_warning_test -/x86_64/mmu_role_test /x86_64/monitor_mwait_test /x86_64/nx_huge_pages_test /x86_64/platform_info_test diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index 4d6753aadfa0b..6b22fb1ce2b90 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -87,7 +87,6 @@ TEST_GEN_PROGS_x86_64 += x86_64/hyperv_svm_test 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/monitor_mwait_test TEST_GEN_PROGS_x86_64 += x86_64/platform_info_test TEST_GEN_PROGS_x86_64 += x86_64/pmu_event_filter_test diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h index 3b819bf673ac7..14342e68e0b5d 100644 --- a/tools/testing/selftests/kvm/include/x86_64/processor.h +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h @@ -142,9 +142,6 @@ struct kvm_x86_cpu_feature { #define CPUID_XSAVE (1ul << 26) #define CPUID_OSXSAVE (1ul << 27) -/* CPUID.0x8000_0001.EDX */ -#define CPUID_GBPAGES (1ul << 26) - /* CPUID.0x8000_000A.EDX */ #define CPUID_NRIPS BIT(3) diff --git a/tools/testing/selftests/kvm/x86_64/mmu_role_test.c b/tools/testing/selftests/kvm/x86_64/mmu_role_test.c deleted file mode 100644 index 383fff2c9587e..0000000000000 --- a/tools/testing/selftests/kvm/x86_64/mmu_role_test.c +++ /dev/null @@ -1,137 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 - -#include "kvm_util.h" -#include "processor.h" - -#define MMIO_GPA 0x100000000ull - -static void guest_code(void) -{ - (void)READ_ONCE(*((uint64_t *)MMIO_GPA)); - (void)READ_ONCE(*((uint64_t *)MMIO_GPA)); - - GUEST_ASSERT(0); -} - -static void guest_pf_handler(struct ex_regs *regs) -{ - /* PFEC == RSVD | PRESENT (read, kernel). */ - GUEST_ASSERT(regs->error_code == 0x9); - GUEST_DONE(); -} - -static void mmu_role_test(u32 *cpuid_reg, u32 evil_cpuid_val) -{ - u32 good_cpuid_val = *cpuid_reg; - struct kvm_vcpu *vcpu; - struct kvm_run *run; - struct kvm_vm *vm; - uint64_t cmd; - - /* Create VM */ - vm = vm_create_with_one_vcpu(&vcpu, guest_code); - run = vcpu->run; - - /* Map 1gb page without a backing memlot. */ - __virt_pg_map(vm, MMIO_GPA, MMIO_GPA, PG_LEVEL_1G); - - vcpu_run(vcpu); - - /* Guest access to the 1gb page should trigger MMIO. */ - TEST_ASSERT(run->exit_reason == KVM_EXIT_MMIO, - "Unexpected exit reason: %u (%s), expected MMIO exit (1gb page w/o memslot)\n", - run->exit_reason, exit_reason_str(run->exit_reason)); - - TEST_ASSERT(run->mmio.len == 8, "Unexpected exit mmio size = %u", run->mmio.len); - - TEST_ASSERT(run->mmio.phys_addr == MMIO_GPA, - "Unexpected exit mmio address = 0x%llx", run->mmio.phys_addr); - - /* - * Effect the CPUID change for the guest and re-enter the guest. Its - * access should now #PF due to the PAGE_SIZE bit being reserved or - * the resulting GPA being invalid. Note, kvm_get_supported_cpuid() - * returns the struct that contains the entry being modified. Eww. - */ - *cpuid_reg = evil_cpuid_val; - vcpu_set_cpuid(vcpu, kvm_get_supported_cpuid()); - - /* - * Add a dummy memslot to coerce KVM into bumping the MMIO generation. - * KVM does not "officially" support mucking with CPUID after KVM_RUN, - * and will incorrectly reuse MMIO SPTEs. Don't delete the memslot! - * KVM x86 zaps all shadow pages on memslot deletion. - */ - vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, - MMIO_GPA << 1, 10, 1, 0); - - /* Set up a #PF handler to eat the RSVD #PF and signal all done! */ - vm_init_descriptor_tables(vm); - vcpu_init_descriptor_tables(vcpu); - vm_install_exception_handler(vm, PF_VECTOR, guest_pf_handler); - - vcpu_run(vcpu); - - cmd = get_ucall(vcpu, NULL); - TEST_ASSERT(cmd == UCALL_DONE, - "Unexpected guest exit, exit_reason=%s, ucall.cmd = %lu\n", - exit_reason_str(run->exit_reason), cmd); - - /* - * Restore the happy CPUID value for the next test. Yes, changes are - * indeed persistent across VM destruction. - */ - *cpuid_reg = good_cpuid_val; - - kvm_vm_free(vm); -} - -int main(int argc, char *argv[]) -{ - struct kvm_cpuid_entry2 *entry; - int opt; - - /* - * All tests are opt-in because TDP doesn't play nice with reserved #PF - * in the GVA->GPA translation. The hardware page walker doesn't let - * software change GBPAGES or MAXPHYADDR, and KVM doesn't manually walk - * the GVA on fault for performance reasons. - */ - bool do_gbpages = false; - bool do_maxphyaddr = false; - - setbuf(stdout, NULL); - - while ((opt = getopt(argc, argv, "gm")) != -1) { - switch (opt) { - case 'g': - do_gbpages = true; - break; - case 'm': - do_maxphyaddr = true; - break; - case 'h': - default: - printf("usage: %s [-g (GBPAGES)] [-m (MAXPHYADDR)]\n", argv[0]); - break; - } - } - - __TEST_REQUIRE(do_gbpages || do_maxphyaddr, "No sub-tests selected"); - - entry = kvm_get_supported_cpuid_entry(0x80000001); - TEST_REQUIRE(entry->edx & CPUID_GBPAGES); - - if (do_gbpages) { - pr_info("Test MMIO after toggling CPUID.GBPAGES\n\n"); - mmu_role_test(&entry->edx, entry->edx & ~CPUID_GBPAGES); - } - - if (do_maxphyaddr) { - pr_info("Test MMIO after changing CPUID.MAXPHYADDR\n\n"); - entry = kvm_get_supported_cpuid_entry(0x80000008); - mmu_role_test(&entry->eax, (entry->eax & ~0xff) | 0x20); - } - - return 0; -} -- 2.39.5