[PATCH 3/3] kvm: selftests: add basic test for state save and restore

From: Paolo Bonzini
Date: Thu Jul 26 2018 - 07:26:59 EST

Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
tools/testing/selftests/kvm/Makefile | 1 +
tools/testing/selftests/kvm/include/x86.h | 4 +
tools/testing/selftests/kvm/lib/kvm_util.c | 8 +-
.../selftests/kvm/lib/kvm_util_internal.h | 1 +
tools/testing/selftests/kvm/lib/x86.c | 118 +++++++++++++++++
tools/testing/selftests/kvm/state_test.c | 123 ++++++++++++++++++
6 files changed, 250 insertions(+), 5 deletions(-)
create mode 100644 tools/testing/selftests/kvm/state_test.c

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 65bda4fb0ad6..dd0e5163f01f 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -10,6 +10,7 @@ TEST_GEN_PROGS_x86_64 = set_sregs_test
TEST_GEN_PROGS_x86_64 += sync_regs_test
TEST_GEN_PROGS_x86_64 += vmx_tsc_adjust_test
TEST_GEN_PROGS_x86_64 += cr4_cpuid_sync_test
+TEST_GEN_PROGS_x86_64 += state_test

TEST_GEN_PROGS += $(TEST_GEN_PROGS_$(UNAME_M))
LIBKVM += $(LIBKVM_$(UNAME_M))
diff --git a/tools/testing/selftests/kvm/include/x86.h b/tools/testing/selftests/kvm/include/x86.h
index 4a5b2c4c1a0f..f73480e09770 100644
--- a/tools/testing/selftests/kvm/include/x86.h
+++ b/tools/testing/selftests/kvm/include/x86.h
@@ -303,6 +303,10 @@ static inline unsigned long get_xmm(int n)
return 0;
}

+struct kvm_x86_state;
+struct kvm_x86_state *vcpu_save_state(struct kvm_vm *vm, uint32_t vcpuid);
+void vcpu_load_state(struct kvm_vm *vm, uint32_t vcpuid, struct kvm_x86_state *state);
+
/*
* Basic CPU control in CR0
*/
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 4930b1bdce62..3fe259cd9eba 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -90,17 +90,15 @@ struct kvm_vm *vm_create(enum vm_guest_mode mode, uint64_t phy_pages, int perm)
TEST_ASSERT(vm != NULL, "Insufficent Memory");

vm->mode = mode;
- kvm_fd = open(KVM_DEV_PATH, perm);
- if (kvm_fd < 0)
+ vm->kvm_fd = open(KVM_DEV_PATH, perm);
+ if (vm->kvm_fd < 0)
exit(KSFT_SKIP);

/* Create VM. */
- vm->fd = ioctl(kvm_fd, KVM_CREATE_VM, NULL);
+ vm->fd = ioctl(vm->kvm_fd, KVM_CREATE_VM, NULL);
TEST_ASSERT(vm->fd >= 0, "KVM_CREATE_VM ioctl failed, "
"rc: %i errno: %i", vm->fd, errno);

- close(kvm_fd);
-
/* Setup mode specific traits. */
switch (vm->mode) {
case VM_MODE_FLAT48PG:
diff --git a/tools/testing/selftests/kvm/lib/kvm_util_internal.h b/tools/testing/selftests/kvm/lib/kvm_util_internal.h
index a0bd1980c81c..6ff6e10fb302 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util_internal.h
+++ b/tools/testing/selftests/kvm/lib/kvm_util_internal.h
@@ -43,6 +43,7 @@ struct vcpu {

struct kvm_vm {
int mode;
+ int kvm_fd;
int fd;
unsigned int page_size;
unsigned int page_shift;
diff --git a/tools/testing/selftests/kvm/lib/x86.c b/tools/testing/selftests/kvm/lib/x86.c
index 2f17675f4275..0d2ea4815975 100644
--- a/tools/testing/selftests/kvm/lib/x86.c
+++ b/tools/testing/selftests/kvm/lib/x86.c
@@ -698,3 +698,115 @@ struct kvm_vm *vm_create_default(uint32_t vcpuid, void *guest_code)

return vm;
}
+
+struct kvm_x86_state {
+ struct kvm_vcpu_events events;
+ struct kvm_mp_state mp_state;
+ struct kvm_regs regs;
+ struct kvm_xsave xsave;
+ struct kvm_xcrs xcrs;
+ struct kvm_sregs sregs;
+ struct kvm_debugregs debugregs;
+ struct kvm_msrs msrs;
+};
+
+static int kvm_get_num_msrs(struct kvm_vm *vm)
+{
+ struct kvm_msr_list nmsrs;
+ int r;
+
+ nmsrs.nmsrs = 0;
+ r = ioctl(vm->kvm_fd, KVM_GET_MSR_INDEX_LIST, &nmsrs);
+ TEST_ASSERT(r == -1 && errno == E2BIG, "Unexpected result from KVM_GET_MSR_INDEX_LIST probe, r: %i",
+ r);
+
+ return nmsrs.nmsrs;
+}
+
+struct kvm_x86_state *vcpu_save_state(struct kvm_vm *vm, uint32_t vcpuid)
+{
+ struct vcpu *vcpu = vcpu_find(vm, vcpuid);
+ struct kvm_msr_list *list;
+ struct kvm_x86_state *state;
+ int nmsrs, r, i;
+
+ nmsrs = kvm_get_num_msrs(vm);
+ list = malloc(sizeof(*list) + nmsrs * sizeof(list->indices[0]));
+ list->nmsrs = nmsrs;
+ r = ioctl(vm->kvm_fd, KVM_GET_MSR_INDEX_LIST, list);
+ TEST_ASSERT(r == 0, "Unexpected result from KVM_GET_MSR_INDEX_LIST, r: %i",
+ r);
+
+ state = malloc(sizeof(*state) + nmsrs * sizeof(state->msrs.entries[0]));
+ r = ioctl(vcpu->fd, KVM_GET_VCPU_EVENTS, &state->events);
+ TEST_ASSERT(r == 0, "Unexpected result from KVM_GET_VCPU_EVENTS, r: %i",
+ r);
+
+ r = ioctl(vcpu->fd, KVM_GET_MP_STATE, &state->mp_state);
+ TEST_ASSERT(r == 0, "Unexpected result from KVM_GET_MP_STATE, r: %i",
+ r);
+
+ r = ioctl(vcpu->fd, KVM_GET_REGS, &state->regs);
+ TEST_ASSERT(r == 0, "Unexpected result from KVM_GET_REGS, r: %i",
+ r);
+
+ r = ioctl(vcpu->fd, KVM_GET_XSAVE, &state->xsave);
+ TEST_ASSERT(r == 0, "Unexpected result from KVM_GET_XSAVE, r: %i",
+ r);
+
+ r = ioctl(vcpu->fd, KVM_GET_XCRS, &state->xcrs);
+ TEST_ASSERT(r == 0, "Unexpected result from KVM_GET_XCRS, r: %i",
+ r);
+
+ r = ioctl(vcpu->fd, KVM_GET_SREGS, &state->sregs);
+ TEST_ASSERT(r == 0, "Unexpected result from KVM_GET_SREGS, r: %i",
+ r);
+
+ state->msrs.nmsrs = nmsrs;
+ for (i = 0; i < nmsrs; i++)
+ state->msrs.entries[i].index = list->indices[i];
+ r = ioctl(vcpu->fd, KVM_GET_MSRS, &state->msrs);
+ TEST_ASSERT(r == nmsrs, "Unexpected result from KVM_GET_MSRS, r: %i (failed at %x)",
+ r, list->indices[r]);
+
+ r = ioctl(vcpu->fd, KVM_GET_DEBUGREGS, &state->debugregs);
+ TEST_ASSERT(r == 0, "Unexpected result from KVM_GET_DEBUGREGS, r: %i",
+ r);
+
+ free(list);
+ return state;
+}
+
+void vcpu_load_state(struct kvm_vm *vm, uint32_t vcpuid, struct kvm_x86_state *state)
+{
+ struct vcpu *vcpu = vcpu_find(vm, vcpuid);
+ int r;
+
+ r = ioctl(vcpu->fd, KVM_SET_XSAVE, &state->xsave);
+ TEST_ASSERT(r == 0, "Unexpected result from KVM_SET_XSAVE, r: %i",
+ r);
+
+ r = ioctl(vcpu->fd, KVM_SET_XCRS, &state->xcrs);
+ TEST_ASSERT(r == 0, "Unexpected result from KVM_SET_XCRS, r: %i",
+ r);
+
+ r = ioctl(vcpu->fd, KVM_SET_SREGS, &state->sregs);
+ TEST_ASSERT(r == 0, "Unexpected result from KVM_SET_SREGS, r: %i",
+ r);
+
+ r = ioctl(vcpu->fd, KVM_SET_MSRS, &state->msrs);
+ TEST_ASSERT(r == state->msrs.nmsrs, "Unexpected result from KVM_SET_MSRS, r: %i (failed at %x)",
+ r, state->msrs.entries[r].index);
+
+ r = ioctl(vcpu->fd, KVM_SET_VCPU_EVENTS, &state->events);
+ TEST_ASSERT(r == 0, "Unexpected result from KVM_SET_VCPU_EVENTS, r: %i",
+ r);
+
+ r = ioctl(vcpu->fd, KVM_SET_DEBUGREGS, &state->debugregs);
+ TEST_ASSERT(r == 0, "Unexpected result from KVM_SET_DEBUGREGS, r: %i",
+ r);
+
+ r = ioctl(vcpu->fd, KVM_SET_REGS, &state->regs);
+ TEST_ASSERT(r == 0, "Unexpected result from KVM_SET_REGS, r: %i",
+ r);
+}
diff --git a/tools/testing/selftests/kvm/state_test.c b/tools/testing/selftests/kvm/state_test.c
new file mode 100644
index 000000000000..1da3d173902c
--- /dev/null
+++ b/tools/testing/selftests/kvm/state_test.c
@@ -0,0 +1,123 @@
+/*
+ * KVM_SET_SREGS tests
+ *
+ * Copyright (C) 2018, Google LLC.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ *
+ * This is a regression test for the bug fixed by the following commit:
+ * d3802286fa0f ("kvm: x86: Disallow illegal IA32_APIC_BASE MSR values")
+ *
+ * That bug allowed a user-mode program that called the KVM_SET_SREGS
+ * ioctl to put a VCPU's local APIC into an invalid state.
+ *
+ */
+#define _GNU_SOURCE /* for program_invocation_short_name */
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+
+#include "test_util.h"
+
+#include "kvm_util.h"
+#include "x86.h"
+
+#define VCPU_ID 5
+#define PORT_HOST_SYNC 0x1000
+
+static void __exit_to_l0(uint16_t port, uint64_t arg0, uint64_t arg1)
+{
+ __asm__ __volatile__("in %[port], %%al"
+ :
+ : [port]"d"(port), "D"(arg0), "S"(arg1)
+ : "rax");
+}
+
+#define exit_to_l0(_port, _arg0, _arg1) \
+ __exit_to_l0(_port, (uint64_t) (_arg0), (uint64_t) (_arg1))
+
+#define GUEST_ASSERT(_condition) do { \
+ if (!(_condition)) \
+ exit_to_l0(PORT_ABORT, "Failed guest assert: " #_condition, 0);\
+} while (0)
+
+void guest_code(void)
+{
+ int i;
+ for (i = 0;; i++) {
+ exit_to_l0(PORT_HOST_SYNC, "hello", i);
+ }
+}
+
+void bad_code(void)
+{
+ for (;;)
+ exit_to_l0(PORT_HOST_SYNC, "goodbye", 0xdeadbeef);
+}
+
+int main(int argc, char *argv[])
+{
+ struct kvm_regs regs1, regs2;
+ struct kvm_vm *vm;
+ struct kvm_run *run;
+ struct kvm_x86_state *state;
+ ulong creation_rsp;
+ int rc;
+
+ /* Create VM */
+ vm = vm_create_default(VCPU_ID, guest_code);
+ run = vcpu_state(vm, VCPU_ID);
+
+ vcpu_regs_get(vm, VCPU_ID, &regs1);
+ creation_rsp = regs1.rsp;
+
+ _vcpu_run(vm, VCPU_ID);
+ TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
+ "Unexpected exit reason: %u (%s),\n",
+ run->exit_reason,
+ exit_reason_str(run->exit_reason));
+
+ memset(&regs1, 0, sizeof(regs1));
+ vcpu_regs_get(vm, VCPU_ID, &regs1);
+ TEST_ASSERT(!strcmp((const char *)regs1.rdi, "hello") &&
+ regs1.rsi == 0, "Unexpected register values after vmexit; rdi: %lx rsi: %lx",
+ (ulong) regs1.rdi, (ulong) regs1.rsi);
+
+ state = vcpu_save_state(vm, VCPU_ID);
+ kvm_vm_free(vm);
+
+ /* Restore state in VM. */
+ vm = vm_create_default(VCPU_ID, bad_code);
+ vcpu_regs_get(vm, VCPU_ID, &regs2);
+
+ /* stack_vaddr should be the same, or something is nondeterministic
+ * in VM state creation. Check just to be safe.
+ */
+ TEST_ASSERT(creation_rsp == regs2.rsp,
+ "Mismatching stack_vaddr - first %lx, second %lx",
+ (ulong) creation_rsp, (ulong) regs2.rsp);
+
+ vcpu_load_state(vm, VCPU_ID, state);
+ memset(&regs2, 0, sizeof(regs2));
+ vcpu_regs_get(vm, VCPU_ID, &regs2);
+ TEST_ASSERT(!memcmp(&regs1, &regs2, sizeof(regs2)),
+ "Unexpected register values after vcpu_load_state; rdi: %lx rsi: %lx",
+ (ulong) regs2.rdi, (ulong) regs2.rsi);
+
+ _vcpu_run(vm, VCPU_ID);
+ TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
+ "Unexpected exit reason: %u (%s),\n",
+ run->exit_reason,
+ exit_reason_str(run->exit_reason));
+
+ vcpu_regs_get(vm, VCPU_ID, &regs2);
+ TEST_ASSERT(!strcmp((const char *)regs2.rdi, "hello") &&
+ regs2.rsi == 1, "Unexpected register values after second vmexit; rdi: %lx rsi: %lx",
+ (ulong) regs2.rdi, (ulong) regs2.rsi);
+
+
+ kvm_vm_free(vm);
+ free(state);
+}
--
2.17.1