KVM: selftests: Remove the obsolete/dead MMU role test

Remove the MMU role test, which was made obsolete by KVM commit
feb627e8d6f6 ("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 <seanjc@google.com>
Link: https://lore.kernel.org/r/20220614200707.3315957-14-seanjc@google.com

diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index f44ebf4..9142933 100644 (file)
--- 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 4d6753a..6b22fb1 100644 (file)
--- 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 3b819bf..14342e6 100644 (file)
--- 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 (file)
index 383fff2..0000000
--- 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;
-}