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authorJim Mattson <jmattson@google.com>2020-10-26 11:09:22 -0700
committerPaolo Bonzini <pbonzini@redhat.com>2020-10-31 10:04:38 -0400
commit97a71a5455997d72adfd74e9d575d782d7c2ab9a (patch)
treee0457dba18b679dfb5fa2c5fee815104cfc46495
parentd383b3146d805a743658225c8973f5d38c6fedf4 (diff)
downloadlinux-97a71a5455997d72adfd74e9d575d782d7c2ab9a.tar.bz2
KVM: selftests: test behavior of unmapped L2 APIC-access address
Add a regression test for commit 671ddc700fd0 ("KVM: nVMX: Don't leak L1 MMIO regions to L2"). First, check to see that an L2 guest can be launched with a valid APIC-access address that is backed by a page of L1 physical memory. Next, set the APIC-access address to a (valid) L1 physical address that is not backed by memory. KVM can't handle this situation, so resuming L2 should result in a KVM exit for internal error (emulation). Signed-off-by: Jim Mattson <jmattson@google.com> Reviewed-by: Ricardo Koller <ricarkol@google.com> Reviewed-by: Peter Shier <pshier@google.com> Message-Id: <20201026180922.3120555-1-jmattson@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--tools/testing/selftests/kvm/.gitignore1
-rw-r--r--tools/testing/selftests/kvm/Makefile1
-rw-r--r--tools/testing/selftests/kvm/include/x86_64/vmx.h6
-rw-r--r--tools/testing/selftests/kvm/lib/x86_64/vmx.c9
-rw-r--r--tools/testing/selftests/kvm/x86_64/vmx_apic_access_test.c142
5 files changed, 159 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index 307ceaadbbb9..d2c2d6205008 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -15,6 +15,7 @@
/x86_64/vmx_preemption_timer_test
/x86_64/svm_vmcall_test
/x86_64/sync_regs_test
+/x86_64/vmx_apic_access_test
/x86_64/vmx_close_while_nested_test
/x86_64/vmx_dirty_log_test
/x86_64/vmx_set_nested_state_test
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 7ebe71fbca53..30afbad36cd5 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -49,6 +49,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/state_test
TEST_GEN_PROGS_x86_64 += x86_64/vmx_preemption_timer_test
TEST_GEN_PROGS_x86_64 += x86_64/svm_vmcall_test
TEST_GEN_PROGS_x86_64 += x86_64/sync_regs_test
+TEST_GEN_PROGS_x86_64 += x86_64/vmx_apic_access_test
TEST_GEN_PROGS_x86_64 += x86_64/vmx_close_while_nested_test
TEST_GEN_PROGS_x86_64 += x86_64/vmx_dirty_log_test
TEST_GEN_PROGS_x86_64 += x86_64/vmx_set_nested_state_test
diff --git a/tools/testing/selftests/kvm/include/x86_64/vmx.h b/tools/testing/selftests/kvm/include/x86_64/vmx.h
index 54d624dd6c10..e78d7e26ba61 100644
--- a/tools/testing/selftests/kvm/include/x86_64/vmx.h
+++ b/tools/testing/selftests/kvm/include/x86_64/vmx.h
@@ -573,6 +573,10 @@ struct vmx_pages {
void *eptp_hva;
uint64_t eptp_gpa;
void *eptp;
+
+ void *apic_access_hva;
+ uint64_t apic_access_gpa;
+ void *apic_access;
};
union vmx_basic {
@@ -615,5 +619,7 @@ void nested_map_memslot(struct vmx_pages *vmx, struct kvm_vm *vm,
uint32_t memslot, uint32_t eptp_memslot);
void prepare_eptp(struct vmx_pages *vmx, struct kvm_vm *vm,
uint32_t eptp_memslot);
+void prepare_virtualize_apic_accesses(struct vmx_pages *vmx, struct kvm_vm *vm,
+ uint32_t eptp_memslot);
#endif /* SELFTEST_KVM_VMX_H */
diff --git a/tools/testing/selftests/kvm/lib/x86_64/vmx.c b/tools/testing/selftests/kvm/lib/x86_64/vmx.c
index f1e00d43eea2..2448b30e8efa 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/vmx.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/vmx.c
@@ -542,3 +542,12 @@ void prepare_eptp(struct vmx_pages *vmx, struct kvm_vm *vm,
vmx->eptp_hva = addr_gva2hva(vm, (uintptr_t)vmx->eptp);
vmx->eptp_gpa = addr_gva2gpa(vm, (uintptr_t)vmx->eptp);
}
+
+void prepare_virtualize_apic_accesses(struct vmx_pages *vmx, struct kvm_vm *vm,
+ uint32_t eptp_memslot)
+{
+ vmx->apic_access = (void *)vm_vaddr_alloc(vm, getpagesize(),
+ 0x10000, 0, 0);
+ vmx->apic_access_hva = addr_gva2hva(vm, (uintptr_t)vmx->apic_access);
+ vmx->apic_access_gpa = addr_gva2gpa(vm, (uintptr_t)vmx->apic_access);
+}
diff --git a/tools/testing/selftests/kvm/x86_64/vmx_apic_access_test.c b/tools/testing/selftests/kvm/x86_64/vmx_apic_access_test.c
new file mode 100644
index 000000000000..1f65342d6cb7
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/vmx_apic_access_test.c
@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * vmx_apic_access_test
+ *
+ * Copyright (C) 2020, Google LLC.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ *
+ * The first subtest simply checks to see that an L2 guest can be
+ * launched with a valid APIC-access address that is backed by a
+ * page of L1 physical memory.
+ *
+ * The second subtest sets the APIC-access address to a (valid) L1
+ * physical address that is not backed by memory. KVM can't handle
+ * this situation, so resuming L2 should result in a KVM exit for
+ * internal error (emulation). This is not an architectural
+ * requirement. It is just a shortcoming of KVM. The internal error
+ * is unfortunate, but it's better than what used to happen!
+ */
+
+#include "test_util.h"
+#include "kvm_util.h"
+#include "processor.h"
+#include "vmx.h"
+
+#include <string.h>
+#include <sys/ioctl.h>
+
+#include "kselftest.h"
+
+#define VCPU_ID 0
+
+/* The virtual machine object. */
+static struct kvm_vm *vm;
+
+static void l2_guest_code(void)
+{
+ /* Exit to L1 */
+ __asm__ __volatile__("vmcall");
+}
+
+static void l1_guest_code(struct vmx_pages *vmx_pages, unsigned long high_gpa)
+{
+#define L2_GUEST_STACK_SIZE 64
+ unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
+ uint32_t control;
+
+ GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
+ GUEST_ASSERT(load_vmcs(vmx_pages));
+
+ /* Prepare the VMCS for L2 execution. */
+ prepare_vmcs(vmx_pages, l2_guest_code,
+ &l2_guest_stack[L2_GUEST_STACK_SIZE]);
+ control = vmreadz(CPU_BASED_VM_EXEC_CONTROL);
+ control |= CPU_BASED_ACTIVATE_SECONDARY_CONTROLS;
+ vmwrite(CPU_BASED_VM_EXEC_CONTROL, control);
+ control = vmreadz(SECONDARY_VM_EXEC_CONTROL);
+ control |= SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
+ vmwrite(SECONDARY_VM_EXEC_CONTROL, control);
+ vmwrite(APIC_ACCESS_ADDR, vmx_pages->apic_access_gpa);
+
+ /* Try to launch L2 with the memory-backed APIC-access address. */
+ GUEST_SYNC(vmreadz(APIC_ACCESS_ADDR));
+ GUEST_ASSERT(!vmlaunch());
+ GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
+
+ vmwrite(APIC_ACCESS_ADDR, high_gpa);
+
+ /* Try to resume L2 with the unbacked APIC-access address. */
+ GUEST_SYNC(vmreadz(APIC_ACCESS_ADDR));
+ GUEST_ASSERT(!vmresume());
+ GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
+
+ GUEST_DONE();
+}
+
+int main(int argc, char *argv[])
+{
+ unsigned long apic_access_addr = ~0ul;
+ unsigned int paddr_width;
+ unsigned int vaddr_width;
+ vm_vaddr_t vmx_pages_gva;
+ unsigned long high_gpa;
+ struct vmx_pages *vmx;
+ bool done = false;
+
+ nested_vmx_check_supported();
+
+ vm = vm_create_default(VCPU_ID, 0, (void *) l1_guest_code);
+ vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
+
+ kvm_get_cpu_address_width(&paddr_width, &vaddr_width);
+ high_gpa = (1ul << paddr_width) - getpagesize();
+ if ((unsigned long)DEFAULT_GUEST_PHY_PAGES * getpagesize() > high_gpa) {
+ print_skip("No unbacked physical page available");
+ exit(KSFT_SKIP);
+ }
+
+ vmx = vcpu_alloc_vmx(vm, &vmx_pages_gva);
+ prepare_virtualize_apic_accesses(vmx, vm, 0);
+ vcpu_args_set(vm, VCPU_ID, 2, vmx_pages_gva, high_gpa);
+
+ while (!done) {
+ volatile struct kvm_run *run = vcpu_state(vm, VCPU_ID);
+ struct ucall uc;
+
+ vcpu_run(vm, VCPU_ID);
+ if (apic_access_addr == high_gpa) {
+ TEST_ASSERT(run->exit_reason ==
+ KVM_EXIT_INTERNAL_ERROR,
+ "Got exit reason other than KVM_EXIT_INTERNAL_ERROR: %u (%s)\n",
+ run->exit_reason,
+ exit_reason_str(run->exit_reason));
+ TEST_ASSERT(run->internal.suberror ==
+ KVM_INTERNAL_ERROR_EMULATION,
+ "Got internal suberror other than KVM_INTERNAL_ERROR_EMULATION: %u\n",
+ run->internal.suberror);
+ break;
+ }
+ TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
+ "Got exit_reason other than KVM_EXIT_IO: %u (%s)\n",
+ run->exit_reason,
+ exit_reason_str(run->exit_reason));
+
+ switch (get_ucall(vm, VCPU_ID, &uc)) {
+ case UCALL_ABORT:
+ TEST_FAIL("%s at %s:%ld", (const char *)uc.args[0],
+ __FILE__, uc.args[1]);
+ /* NOT REACHED */
+ case UCALL_SYNC:
+ apic_access_addr = uc.args[1];
+ break;
+ case UCALL_DONE:
+ done = true;
+ break;
+ default:
+ TEST_ASSERT(false, "Unknown ucall %lu", uc.cmd);
+ }
+ }
+ kvm_vm_free(vm);
+ return 0;
+}