[PATCH 08/10] kvm: selftests: add test for nested state save/restore

From: Paolo Bonzini
Date: Sat Jul 28 2018 - 19:10:32 EST

Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
tools/testing/selftests/kvm/include/vmx.h | 32 +++++++++++++
tools/testing/selftests/kvm/lib/x86.c | 27 ++++++++++-
tools/testing/selftests/kvm/state_test.c | 75 ++++++++++++++++++++++++++++++-
3 files changed, 131 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/vmx.h b/tools/testing/selftests/kvm/include/vmx.h
index 9caaf56696a4..2b37f9b6f7df 100644
--- a/tools/testing/selftests/kvm/include/vmx.h
+++ b/tools/testing/selftests/kvm/include/vmx.h
@@ -380,6 +380,30 @@ static inline int vmptrld(uint64_t vmcs_pa)
return ret;
}

+static inline int vmptrst(uint64_t *value)
+{
+ uint64_t tmp;
+ uint8_t ret;
+
+ __asm__ __volatile__("vmptrst %[value]; setna %[ret]"
+ : [value]"=m"(tmp), [ret]"=rm"(ret)
+ : : "cc", "memory");
+
+ *value = tmp;
+ return ret;
+}
+
+/*
+ * A wrapper around vmptrst that ignores errors and returns zero if the
+ * vmptrst instruction fails.
+ */
+static inline uint64_t vmptrstz(void)
+{
+ uint64_t value = 0;
+ vmptrst(&value);
+ return value;
+}
+
/*
* No guest state (e.g. GPRs) is established by this vmlaunch.
*/
@@ -444,6 +468,15 @@ static inline int vmresume(void)
return ret;
}

+static inline void vmcall(void)
+{
+ /* Currently, L1 destroys our GPRs during vmexits. */
+ __asm__ __volatile__("push %%rbp; vmcall; pop %%rbp" : : :
+ "rax", "rbx", "rcx", "rdx",
+ "rsi", "rdi", "r8", "r9", "r10", "r11", "r12",
+ "r13", "r14", "r15");
+}
+
static inline int vmread(uint64_t encoding, uint64_t *value)
{
uint64_t tmp;
diff --git a/tools/testing/selftests/kvm/lib/x86.c b/tools/testing/selftests/kvm/lib/x86.c
index 78aabcb91de1..e38345252df5 100644
--- a/tools/testing/selftests/kvm/lib/x86.c
+++ b/tools/testing/selftests/kvm/lib/x86.c
@@ -736,6 +736,10 @@ struct kvm_x86_state {
struct kvm_xcrs xcrs;
struct kvm_sregs sregs;
struct kvm_debugregs debugregs;
+ union {
+ struct kvm_nested_state nested;
+ char nested_[16384];
+ };
struct kvm_msrs msrs;
};

@@ -764,6 +762,14 @@ struct kvm_x86_state *vcpu_save_state(struct kvm_vm *vm, uint32_t vcpuid)
struct kvm_msr_list *list;
struct kvm_x86_state *state;
int nmsrs, r, i;
+ static int nested_size = -1;
+
+ if (nested_size == -1) {
+ nested_size = kvm_check_cap(KVM_CAP_NESTED_STATE);
+ TEST_ASSERT(nested_size <= sizeof(state->nested_),
+ "Nested state size too big, %i > %zi",
+ nested_size, sizeof(state->nested_));
+ }

nmsrs = kvm_get_num_msrs(vm);
list = malloc(sizeof(*list) + nmsrs * sizeof(list->indices[0]));
@@ -797,6 +803,17 @@ struct kvm_x86_state *vcpu_save_state(struct kvm_vm *vm, uint32_t vcpuid)
TEST_ASSERT(r == 0, "Unexpected result from KVM_GET_SREGS, r: %i",
r);

+ if (nested_size) {
+ state->nested.size = sizeof(state->nested_);
+ r = ioctl(vcpu->fd, KVM_GET_NESTED_STATE, &state->nested);
+ TEST_ASSERT(r == 0, "Unexpected result from KVM_GET_NESTED_STATE, r: %i",
+ r);
+ TEST_ASSERT(state->nested.size <= nested_size,
+ "Nested state size too big, %i (KVM_CHECK_CAP gave %i)",
+ state->nested.size, nested_size);
+ } else
+ state->nested.size = 0;
+
state->msrs.nmsrs = nmsrs;
for (i = 0; i < nmsrs; i++)
state->msrs.entries[i].index = list->indices[i];
@@ -817,6 +834,12 @@ void vcpu_load_state(struct kvm_vm *vm, uint32_t vcpuid, struct kvm_x86_state *s
struct vcpu *vcpu = vcpu_find(vm, vcpuid);
int r;

+ if (state->nested.size) {
+ r = ioctl(vcpu->fd, KVM_SET_NESTED_STATE, &state->nested);
+ TEST_ASSERT(r == 0, "Unexpected result from KVM_SET_NESTED_STATE, r: %i",
+ r);
+ }
+
r = ioctl(vcpu->fd, KVM_SET_XSAVE, &state->xsave);
TEST_ASSERT(r == 0, "Unexpected result from KVM_SET_XSAVE, r: %i",
r);
diff --git a/tools/testing/selftests/kvm/state_test.c b/tools/testing/selftests/kvm/state_test.c
index e47b27b5406e..447da4f76b56 100644
--- a/tools/testing/selftests/kvm/state_test.c
+++ b/tools/testing/selftests/kvm/state_test.c
@@ -18,6 +18,7 @@

#include "kvm_util.h"
#include "x86.h"
+#include "vmx.h"

#define VCPU_ID 5
#define PORT_SYNC 0x1000
@@ -45,16 +46,75 @@ static inline void __exit_to_l0(uint16_t port, uint64_t arg0, uint64_t arg1)

static bool have_nested_state;

-void guest_code(void)
+void l2_guest_code(void)
+{
+ GUEST_SYNC(5);
+
+ /* Exit to L1 */
+ vmcall();
+
+ GUEST_SYNC(7);
+
+ /* Done, exit to L1 and never come back. */
+ vmcall();
+}
+
+void l1_guest_code(struct vmx_pages *vmx_pages)
+{
+#define L2_GUEST_STACK_SIZE 64
+ unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
+
+ GUEST_ASSERT(vmx_pages->vmcs_gpa);
+ GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
+ GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);
+
+ GUEST_SYNC(3);
+ GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);
+
+ prepare_vmcs(vmx_pages, l2_guest_code,
+ &l2_guest_stack[L2_GUEST_STACK_SIZE]);
+
+ GUEST_SYNC(4);
+ GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);
+ GUEST_ASSERT(!vmlaunch());
+ GUEST_ASSERT(vmptrstz() == vmx_pages->vmcs_gpa);
+ GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
+
+ /* Check that the launched state is preserved. */
+ GUEST_ASSERT(vmlaunch());
+
+ GUEST_ASSERT(!vmresume());
+ GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
+
+ GUEST_SYNC(6);
+ GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
+
+ GUEST_ASSERT(!vmresume());
+ GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
+
+ vmwrite(GUEST_RIP, vmreadz(GUEST_RIP) + 3);
+
+ GUEST_ASSERT(!vmresume());
+ GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
+ GUEST_SYNC(8);
+}
+
+void guest_code(struct vmx_pages *vmx_pages)
{
GUEST_SYNC(1);
GUEST_SYNC(2);

+ if (vmx_pages)
+ l1_guest_code(vmx_pages);
+
exit_to_l0(PORT_DONE, 0, 0);
}

int main(int argc, char *argv[])
{
+ struct vmx_pages *vmx_pages = NULL;
+ vm_vaddr_t vmx_pages_gva = 0;
+
struct kvm_regs regs1, regs2;
struct kvm_vm *vm;
struct kvm_run *run;
@@ -69,6 +133,15 @@ int main(int argc, char *argv[])
run = vcpu_state(vm, VCPU_ID);

vcpu_regs_get(vm, VCPU_ID, &regs1);
+
+ if (kvm_check_cap(KVM_CAP_NESTED_STATE)) {
+ vmx_pages = vcpu_alloc_vmx(vm, &vmx_pages_gva);
+ vcpu_args_set(vm, VCPU_ID, 1, vmx_pages_gva);
+ } else {
+ printf("will skip nested state checks\n");
+ vcpu_args_set(vm, VCPU_ID, 1, 0);
+ }
+
for (stage = 1;; stage++) {
_vcpu_run(vm, VCPU_ID);
TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
--
1.8.3.1