Kernel commit 8fcc4b5923af ("kvm: nVMX: Introduce KVM_CAP_NESTED_STATE")
introduced new IOCTLs to extract and restore vCPU state related to
Intel VMX & AMD SVM.
Utilize these IOCTLs to add support for migration of VMs which are
running nested hypervisors.
Reviewed-by: Nikita Leshenko <address@hidden>
Signed-off-by: Liran Alon <address@hidden>
---
accel/kvm/kvm-all.c | 8 ++
include/sysemu/kvm.h | 1 +
target/i386/cpu.h | 3 +
target/i386/kvm.c | 80 +++++++++++++++++
target/i386/machine.c | 196 ++++++++++++++++++++++++++++++++++++++++++
5 files changed, 288 insertions(+)
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 59a3aa3a40da..4fdf5b04b131 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -88,6 +88,7 @@ struct KVMState
#ifdef KVM_CAP_SET_GUEST_DEBUG
QTAILQ_HEAD(, kvm_sw_breakpoint) kvm_sw_breakpoints;
#endif
+ int max_nested_state_len;
int many_ioeventfds;
int intx_set_mask;
bool sync_mmu;
@@ -1678,6 +1679,8 @@ static int kvm_init(MachineState *ms)
s->debugregs = kvm_check_extension(s, KVM_CAP_DEBUGREGS);
#endif
+ s->max_nested_state_len = kvm_check_extension(s, KVM_CAP_NESTED_STATE);
+
#ifdef KVM_CAP_IRQ_ROUTING
kvm_direct_msi_allowed = (kvm_check_extension(s, KVM_CAP_SIGNAL_MSI) > 0);
#endif
@@ -2245,6 +2248,11 @@ int kvm_has_debugregs(void)
return kvm_state->debugregs;
}
+int kvm_max_nested_state_length(void)
+{
+ return kvm_state->max_nested_state_len;
+}
+
int kvm_has_many_ioeventfds(void)
{
if (!kvm_enabled()) {
diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
index 64f55e519df7..acd90aebb6c4 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -210,6 +210,7 @@ bool kvm_has_sync_mmu(void);
int kvm_has_vcpu_events(void);
int kvm_has_robust_singlestep(void);
int kvm_has_debugregs(void);
+int kvm_max_nested_state_length(void);
int kvm_has_pit_state2(void);
int kvm_has_many_ioeventfds(void);
int kvm_has_gsi_routing(void);
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 79d9495ceb0c..a6bb71849869 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -1350,6 +1350,9 @@ typedef struct CPUX86State {
#if defined(CONFIG_KVM) || defined(CONFIG_HVF)
void *xsave_buf;
#endif
+#if defined(CONFIG_KVM)
+ struct kvm_nested_state *nested_state;
+#endif
#if defined(CONFIG_HVF)
HVFX86EmulatorState *hvf_emul;
#endif
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index f43e2d69859e..5950c3ed0d1c 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -931,6 +931,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
struct kvm_cpuid_entry2 *c;
uint32_t signature[3];
int kvm_base = KVM_CPUID_SIGNATURE;
+ int max_nested_state_len;
int r;
Error *local_err = NULL;
@@ -1331,6 +1332,24 @@ int kvm_arch_init_vcpu(CPUState *cs)
if (has_xsave) {
env->xsave_buf = qemu_memalign(4096, sizeof(struct kvm_xsave));
}
+
+ max_nested_state_len = kvm_max_nested_state_length();
+ if (max_nested_state_len > 0) {
+ assert(max_nested_state_len >= offsetof(struct kvm_nested_state,
data));
+ env->nested_state = g_malloc0(max_nested_state_len);
+
+ env->nested_state->size = max_nested_state_len;
+
+ if (IS_INTEL_CPU(env)) {
+ struct kvm_vmx_nested_state_hdr *vmx_hdr =
+ &env->nested_state->hdr.vmx;
+
+ vmx_hdr->vmxon_pa = -1ull;
+ vmx_hdr->vmcs12_pa = -1ull;
+ }
+
+ }
+
cpu->kvm_msr_buf = g_malloc0(MSR_BUF_SIZE);
if (!(env->features[FEAT_8000_0001_EDX] & CPUID_EXT2_RDTSCP)) {
@@ -1352,12 +1371,18 @@ int kvm_arch_init_vcpu(CPUState *cs)
int kvm_arch_destroy_vcpu(CPUState *cs)
{
X86CPU *cpu = X86_CPU(cs);
+ CPUX86State *env = &cpu->env;
if (cpu->kvm_msr_buf) {
g_free(cpu->kvm_msr_buf);
cpu->kvm_msr_buf = NULL;
}
+ if (env->nested_state) {
+ g_free(env->nested_state);
+ env->nested_state = NULL;
+ }
+
return 0;
}
@@ -3072,6 +3097,52 @@ static int kvm_get_debugregs(X86CPU *cpu)
return 0;
}
+static int kvm_put_nested_state(X86CPU *cpu)
+{
+ CPUX86State *env = &cpu->env;
+ int max_nested_state_len = kvm_max_nested_state_length();
+
+ if (max_nested_state_len <= 0) {
+ return 0;
+ }
+
+ assert(env->nested_state->size <= max_nested_state_len);
+ return kvm_vcpu_ioctl(CPU(cpu), KVM_SET_NESTED_STATE, env->nested_state);
+}
+
+static int kvm_get_nested_state(X86CPU *cpu)
+{
+ CPUX86State *env = &cpu->env;
+ int max_nested_state_len = kvm_max_nested_state_length();
+ int ret;
+
+ if (max_nested_state_len <= 0) {
+ return 0;
+ }
+
+ /*
+ * It is possible that migration restored a smaller size into
+ * nested_state->hdr.size than what our kernel support.
+ * We preserve migration origin nested_state->hdr.size for
+ * call to KVM_SET_NESTED_STATE but wish that our next call
+ * to KVM_GET_NESTED_STATE will use max size our kernel support.
+ */
+ env->nested_state->size = max_nested_state_len;
+
+ ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_NESTED_STATE, env->nested_state);
+ if (ret < 0) {
+ return ret;
+ }
+
+ if (env->nested_state->flags & KVM_STATE_NESTED_GUEST_MODE) {
+ env->hflags |= HF_GUEST_MASK;
+ } else {
+ env->hflags &= ~HF_GUEST_MASK;
+ }
+
+ return ret;
+}
+
int kvm_arch_put_registers(CPUState *cpu, int level)
{
X86CPU *x86_cpu = X86_CPU(cpu);
@@ -3079,6 +3150,11 @@ int kvm_arch_put_registers(CPUState *cpu, int level)
assert(cpu_is_stopped(cpu) || qemu_cpu_is_self(cpu));
+ ret = kvm_put_nested_state(x86_cpu);
+ if (ret < 0) {
+ return ret;
+ }
+
if (level >= KVM_PUT_RESET_STATE) {
ret = kvm_put_msr_feature_control(x86_cpu);
if (ret < 0) {
@@ -3194,6 +3270,10 @@ int kvm_arch_get_registers(CPUState *cs)
if (ret < 0) {
goto out;
}
+ ret = kvm_get_nested_state(cpu);
+ if (ret < 0) {
+ goto out;
+ }
ret = 0;
out:
cpu_sync_bndcs_hflags(&cpu->env);
diff --git a/target/i386/machine.c b/target/i386/machine.c
index 225b5d433bc4..95299ebff44a 100644
--- a/target/i386/machine.c
+++ b/target/i386/machine.c
@@ -231,6 +231,15 @@ static int cpu_pre_save(void *opaque)
env->segs[R_SS].flags &= ~(env->segs[R_SS].flags & DESC_DPL_MASK);
}
+#ifdef CONFIG_KVM
+ /* Verify we have nested virtualization state from kernel if required */
+ if (cpu_has_nested_virt(env) && !env->nested_state) {
+ error_report("Guest enabled nested virtualization but kernel "
+ "does not support saving of nested state");
+ return -EINVAL;
+ }
+#endif
+
return 0;
}
@@ -278,6 +287,16 @@ static int cpu_post_load(void *opaque, int version_id)
env->hflags &= ~HF_CPL_MASK;
env->hflags |= (env->segs[R_SS].flags >> DESC_DPL_SHIFT) & HF_CPL_MASK;
+#ifdef CONFIG_KVM
+ if ((env->hflags & HF_GUEST_MASK) &&
+ (!env->nested_state ||
+ !(env->nested_state->flags & KVM_STATE_NESTED_GUEST_MODE))) {
+ error_report("vCPU set in guest-mode inconsistent with "
+ "migrated kernel nested state");
+ return -EINVAL;
+ }
+#endif
+
env->fpstt = (env->fpus_vmstate >> 11) & 7;
env->fpus = env->fpus_vmstate & ~0x3800;
env->fptag_vmstate ^= 0xff;
@@ -851,6 +870,180 @@ static const VMStateDescription vmstate_tsc_khz = {
}
};
+#ifdef CONFIG_KVM
+
+static bool vmx_vmcs12_needed(void *opaque)
+{
+ struct kvm_nested_state *nested_state = opaque;
+ return (nested_state->size >
+ offsetof(struct kvm_nested_state, data.vmx[0].vmcs12));
+}
+
+static const VMStateDescription vmstate_vmx_vmcs12 = {
+ .name = "cpu/kvm_nested_state/vmx/vmcs12",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .needed = vmx_vmcs12_needed,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT8_ARRAY(data.vmx[0].vmcs12,
+ struct kvm_nested_state, 0x1000),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+static bool vmx_shadow_vmcs12_needed(void *opaque)
+{
+ struct kvm_nested_state *nested_state = opaque;
+ return (nested_state->size >
+ offsetof(struct kvm_nested_state, data.vmx[0].shadow_vmcs12));
+}
+
+static const VMStateDescription vmstate_vmx_shadow_vmcs12 = {
+ .name = "cpu/kvm_nested_state/vmx/shadow_vmcs12",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .needed = vmx_shadow_vmcs12_needed,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT8_ARRAY(data.vmx[0].shadow_vmcs12,
+ struct kvm_nested_state, 0x1000),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+static bool vmx_nested_state_needed(void *opaque)
+{
+ struct kvm_nested_state *nested_state = opaque;
+
+ return ((nested_state->format == KVM_STATE_NESTED_FORMAT_VMX) &&
+ ((nested_state->hdr.vmx.vmxon_pa != -1ull) ||
+ (nested_state->hdr.vmx.smm.flags & KVM_STATE_NESTED_SMM_VMXON)));
+}
+
+static const VMStateDescription vmstate_vmx_nested_state = {
+ .name = "cpu/kvm_nested_state/vmx",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .needed = vmx_nested_state_needed,
+ .fields = (VMStateField[]) {
+ VMSTATE_U64(hdr.vmx.vmxon_pa, struct kvm_nested_state),
+ VMSTATE_U64(hdr.vmx.vmcs12_pa, struct kvm_nested_state),
+ VMSTATE_U16(hdr.vmx.smm.flags, struct kvm_nested_state),
+ VMSTATE_END_OF_LIST()
+ },
+ .subsections = (const VMStateDescription*[]) {
+ &vmstate_vmx_vmcs12,
+ &vmstate_vmx_shadow_vmcs12,
+ NULL,
+ }
+};
+
+static bool svm_nested_state_needed(void *opaque)
+{
+ struct kvm_nested_state *nested_state = opaque;
+
+ return (nested_state->format == KVM_STATE_NESTED_FORMAT_SVM);
+}
+
+static const VMStateDescription vmstate_svm_nested_state = {
+ .name = "cpu/kvm_nested_state/svm",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .needed = svm_nested_state_needed,
+ .fields = (VMStateField[]) {
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+static bool nested_state_needed(void *opaque)
+{
+ X86CPU *cpu = opaque;
+ CPUX86State *env = &cpu->env;
+
+ return (env->nested_state &&
+ (vmx_nested_state_needed(env->nested_state) ||
+ svm_nested_state_needed(env->nested_state)));
+}
+
+static int nested_state_post_load(void *opaque, int version_id)
+{
+ X86CPU *cpu = opaque;
+ CPUX86State *env = &cpu->env;
+ struct kvm_nested_state *nested_state = env->nested_state;
+ int min_nested_state_len = offsetof(struct kvm_nested_state, data);
+ int max_nested_state_len = kvm_max_nested_state_length();
+
+ /*
+ * If our kernel don't support setting nested state
+ * and we have received nested state from migration stream,
+ * we need to fail migration
+ */
+ if (max_nested_state_len <= 0) {
+ error_report("Received nested state when kernel cannot restore it");
+ return -EINVAL;
+ }
+
+ /*
+ * Verify that the size of received nested_state struct
+ * at least cover required header and is not larger
+ * than the max size that our kernel support
+ */
+ if (nested_state->size < min_nested_state_len) {
+ error_report("Received nested state size less than min: "
+ "len=%d, min=%d",
+ nested_state->size, min_nested_state_len);
+ return -EINVAL;
+ }
+ if (nested_state->size > max_nested_state_len) {
+ error_report("Recieved unsupported nested state size: "
+ "nested_state->size=%d, max=%d",
+ nested_state->size, max_nested_state_len);
+ return -EINVAL;
+ }
+
+ /* Verify format is valid */
+ if ((nested_state->format != KVM_STATE_NESTED_FORMAT_VMX) &&
+ (nested_state->format != KVM_STATE_NESTED_FORMAT_SVM)) {
+ error_report("Received invalid nested state format: %d",
+ nested_state->format);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static const VMStateDescription vmstate_kvm_nested_state = {
+ .name = "cpu/kvm_nested_state",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .fields = (VMStateField[]) {
+ VMSTATE_U16(flags, struct kvm_nested_state),
+ VMSTATE_U16(format, struct kvm_nested_state),
+ VMSTATE_U32(size, struct kvm_nested_state),
+ VMSTATE_END_OF_LIST()
+ },
+ .subsections = (const VMStateDescription*[]) {
+ &vmstate_vmx_nested_state,
+ &vmstate_svm_nested_state,
+ NULL
+ }
+};
+
+static const VMStateDescription vmstate_nested_state = {
+ .name = "cpu/nested_state",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .needed = nested_state_needed,
+ .post_load = nested_state_post_load,
+ .fields = (VMStateField[]) {
+ VMSTATE_STRUCT_POINTER(env.nested_state, X86CPU,
+ vmstate_kvm_nested_state,
+ struct kvm_nested_state),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+#endif
+
static bool mcg_ext_ctl_needed(void *opaque)
{
X86CPU *cpu = opaque;
@@ -1089,6 +1282,9 @@ VMStateDescription vmstate_x86_cpu = {
&vmstate_msr_intel_pt,
&vmstate_msr_virt_ssbd,
&vmstate_svm_npt,
+#ifdef CONFIG_KVM
+ &vmstate_nested_state,
+#endif
NULL
}
};