lib: implement reference TSC enlightenment (#856)

Add a Hyper-V reference time enlightenment to the Hyper-V stack. See the
new tsc module's doc comment for details about how the enlightenment
operates.

Add PHD tests that try to verify both that the enlightenment is present
(by querying the current clocksource) and that it keeps time roughly
correctly (by comparing host and guest time readings). The latter test
also takes readings over a migration to help get some coverage of the
time data phase of live migration (though the migration is not currently
cross-machine, so this is a little less interesting than it might
otherwise be).

Author: gjcolombo

Cargo.lock

@@ -19,7 +19,7 @@ use newtype_uuid::{GenericUuid, TypedUuid, TypedUuidKind, TypedUuidTag};
 use propolis_client::support::nvme_serial_from_str;
 use propolis_client::types::{
     BlobStorageBackend, Board, Chipset, ComponentV0, CrucibleStorageBackend,
-    GuestHypervisorInterface, I440Fx, InstanceEnsureRequest,
+    GuestHypervisorInterface, HyperVFeatureFlag, I440Fx, InstanceEnsureRequest,
     InstanceInitializationMethod, InstanceMetadata, InstanceSpecGetResponse,
     InstanceSpecV0, NvmeDisk, QemuPvpanic, ReplacementComponent, SerialPort,
     SerialPortNumber, VirtioDisk,
@@ -298,7 +298,9 @@ impl VmConfig {
                 cpus: self.vcpus,
                 memory_mb: self.memory,
                 guest_hv_interface: if self.hyperv {
-                    Some(GuestHypervisorInterface::HyperV { features: vec![] })
+                    Some(GuestHypervisorInterface::HyperV {
+                        features: vec![HyperVFeatureFlag::ReferenceTsc],
+                    })
                 } else {
                     None
                 },

bin/propolis-cli/src/main.rs

@@ -94,10 +94,14 @@ use std::sync::Arc;
 use oximeter::types::ProducerRegistry;
 use oximeter_instruments::kstat::KstatSampler;
 use propolis::enlightenment::{
-    bhyve::BhyveGuestInterface, hyperv::HyperV, Enlightenment,
+    bhyve::BhyveGuestInterface,
+    hyperv::{Features as HyperVFeatures, HyperV},
+    Enlightenment,
 };
 use propolis_api_types::{
-    instance_spec::components::board::GuestHypervisorInterface,
+    instance_spec::components::board::{
+        GuestHypervisorInterface, HyperVFeatureFlag,
+    },
     InstanceEnsureResponse, InstanceMigrateInitiateResponse,
     InstanceProperties, InstanceState,
 };
@@ -492,14 +496,23 @@ async fn initialize_vm_objects(
     let vmm_log = log.new(slog::o!("component" => "vmm"));
 
     let (guest_hv_interface, guest_hv_lifecycle) =
-        match spec.board.guest_hv_interface {
+        match &spec.board.guest_hv_interface {
             GuestHypervisorInterface::Bhyve => {
                 let bhyve = Arc::new(BhyveGuestInterface);
                 let lifecycle = bhyve.clone();
                 (bhyve as Arc<dyn Enlightenment>, lifecycle.as_lifecycle())
             }
-            GuestHypervisorInterface::HyperV { .. } => {
-                let hyperv = Arc::new(HyperV::new(&vmm_log));
+            GuestHypervisorInterface::HyperV { features } => {
+                let mut hv_features = HyperVFeatures::default();
+                for f in features {
+                    match f {
+                        HyperVFeatureFlag::ReferenceTsc => {
+                            hv_features.reference_tsc = true
+                        }
+                    }
+                }
+
+                let hyperv = Arc::new(HyperV::new(&vmm_log, hv_features));
                 let lifecycle = hyperv.clone();
                 (hyperv as Arc<dyn Enlightenment>, lifecycle.as_lifecycle())
             }

bin/propolis-server/src/lib/vm/ensure.rs

@@ -115,7 +115,9 @@ pub struct CpuidEntry {
     PartialEq,
 )]
 #[serde(deny_unknown_fields)]
-pub enum HyperVFeatureFlag {}
+pub enum HyperVFeatureFlag {
+    ReferenceTsc,
+}
 
 /// A hypervisor interface to expose to the guest.
 #[derive(Clone, Deserialize, Serialize, Debug, JsonSchema, Default)]

crates/propolis-api-types/src/instance_spec/components/board.rs

@@ -7,6 +7,8 @@
 //! This interface supplies no special enlightenments; it merely identifies
 //! itself as a bhyve hypervisor in CPUID leaf 0x4000_0000.
 
+use std::sync::Arc;
+
 use cpuid_utils::{
     bits::HYPERVISOR_BASE_LEAF, CpuidIdent, CpuidSet, CpuidValues,
 };
@@ -16,6 +18,7 @@ use crate::{
     common::{Lifecycle, VcpuId},
     enlightenment::{AddCpuidError, Enlightenment},
     msr::{MsrId, RdmsrOutcome, WrmsrOutcome},
+    vmm::VmmHdl,
 };
 
 /// An implementation of the bhyve guest-hypervisor interface. This interface
@@ -59,5 +62,5 @@ impl Enlightenment for BhyveGuestInterface {
         WrmsrOutcome::NotHandled
     }
 
-    fn attach(&self, _parent: &MemAccessor) {}
+    fn attach(&self, _parent: &MemAccessor, _vmm_hdl: Arc<VmmHdl>) {}
 }

lib/propolis/src/enlightenment/bhyve.rs

@@ -108,7 +108,7 @@ pub(super) const HYPERV_LEAF_5_VALUES: CpuidValues =
 pub(super) const HV_X64_MSR_GUEST_OS_ID: u32 = 0x4000_0000;
 
 /// Specifies the guest physical address at which the guest would like to place
-/// the hypercall page. See TLFS section 3.13 and the [`MsrHypercalLValue`]
+/// the hypercall page. See TLFS section 3.13 and the [`MsrHypercallValue`]
 /// struct.
 ///
 /// Read-write; requires the [`HyperVLeaf3Eax::HYPERCALL`] privilege.
@@ -121,3 +121,20 @@ pub(super) const HV_X64_MSR_HYPERCALL: u32 = 0x4000_0001;
 ///
 /// Read-only; requires the [`HyperVLeaf3Eax::VP_INDEX`] privilege.
 pub(super) const HV_X64_MSR_VP_INDEX: u32 = 0x4000_0002;
+
+/// Guests may read this register to obtain the time since this VM was created,
+/// in 100-nanosecond units.
+///
+/// Read-only; requires the [`HyperVLeaf3Eax::PARTITION_REFERENCE_COUNTER`]
+/// privilege.
+pub(super) const HV_X64_MSR_TIME_REF_COUNT: u32 = 0x4000_0020;
+
+/// Specifies the guest physical address at which the guest would like to place
+/// the reference TSC page. See TLFS section 12.7 and the
+/// [`MsrReferenceTscValue`] struct.
+///
+/// Read-write; requires the [`HyperVLeaf3Eax::PARTITION_REFERENCE_TSC`]
+/// privilege.
+///
+/// [`MsrReferenceTscValue`]: super::tsc::MsrReferenceTscValue
+pub(super) const HV_X64_MSR_REFERENCE_TSC: u32 = 0x4000_0021;