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Message-Id: <20220614200707.3315957-14-seanjc@google.com>
Date: Tue, 14 Jun 2022 20:06:38 +0000
From: Sean Christopherson <seanjc@...gle.com>
To: Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
Sean Christopherson <seanjc@...gle.com>,
Jim Mattson <jmattson@...gle.com>
Subject: [PATCH v2 13/42] 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@...gle.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 dd5c88c11059..0ab0e255d292 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/platform_info_test
/x86_64/pmu_event_filter_test
/x86_64/set_boot_cpu_id
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index b52c130f7b2f..2ca5400220b9 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -83,7 +83,6 @@ 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/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/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index b5d2e6c69c1a..95d1b402da9b 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -140,9 +140,6 @@ 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 383fff2c9587..000000000000
--- 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;
-}
--
2.36.1.476.g0c4daa206d-goog
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