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Add implementation of adding vCPUs to VMM
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Actually add the vCPUS to the VMM via API PUT requests to hotplug
endpoint. Must add at least 1 vCPU, and the total number of vCPUs after
hotplug must not exceed MAX_SUPPORTED_VCPUS (currently 32).

Signed-off-by: James Curtis <[email protected]>
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@JamesC1305 @roypat
JamesC1305 authored and roypat committed Aug 7, 2024
1 parent 5eaa199 commit 4faee33
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Showing 3 changed files with 154 additions and 27 deletions.
10 changes: 5 additions & 5 deletions src/vmm/src/lib.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -610,24 +610,24 @@ impl Vmm {
config: HotplugVcpuConfig,
) -> Result<MachineConfigUpdate, HotplugVcpuError> {
use crate::logger::IncMetric;
if config.vcpu_count < 1 {
if config.add < 1 {
return Err(HotplugVcpuError::VcpuCountTooLow);
} else if self
.vcpus_handles
.len()
.checked_add(config.vcpu_count.into())
.checked_add(config.add.into())
.ok_or(HotplugVcpuError::VcpuCountTooHigh)?
> MAX_SUPPORTED_VCPUS.into()
{
return Err(HotplugVcpuError::VcpuCountTooHigh);
}

// Create and start new vcpus
let mut vcpus = Vec::with_capacity(config.vcpu_count.into());
let mut vcpus = Vec::with_capacity(config.add.into());

#[allow(clippy::cast_possible_truncation)]
let start_idx = self.vcpus_handles.len().try_into().unwrap();
for cpu_idx in start_idx..(start_idx + config.vcpu_count) {
for cpu_idx in start_idx..(start_idx + config.add) {
let exit_evt = self
.vcpus_exit_evt
.try_clone()
Expand All @@ -647,7 +647,7 @@ impl Vmm {
.map_err(HotplugVcpuError::VcpuStart)?;

#[allow(clippy::cast_lossless)]
METRICS.hotplug.vcpus_added.add(config.vcpu_count.into());
METRICS.hotplug.vcpus_added.add(config.add.into());

// Update VM config to reflect new CPUs added
#[allow(clippy::cast_possible_truncation)]
Expand Down
169 changes: 147 additions & 22 deletions src/vmm/src/rpc_interface.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -670,7 +670,7 @@ impl RuntimeApiController {
self.vmm.lock().expect("Poisoned lock").version(),
)),
#[cfg(target_arch = "x86_64")]
HotplugRequest(config) => Ok(VmmData::Empty),
HotplugRequest(request_type) => self.handle_hotplug_request(request_type),
PatchMMDS(value) => self.patch_mmds(value),
Pause => self.pause(),
PutMMDS(value) => self.put_mmds(value),
Expand Down Expand Up @@ -867,6 +867,31 @@ impl RuntimeApiController {
.map_err(NetworkInterfaceError::DeviceUpdate)
.map_err(VmmActionError::NetworkConfig)
}

#[cfg(target_arch = "x86_64")]
fn handle_hotplug_request(
&mut self,
cfg: HotplugRequestConfig,
) -> Result<VmmData, VmmActionError> {
match cfg {
HotplugRequestConfig::Vcpu(cfg) => {
let result = self.vmm.lock().expect("Poisoned lock").hotplug_vcpus(cfg);
result
.map_err(|err| VmmActionError::HotplugRequest(HotplugRequestError::Vcpu(err)))
.and_then(|machine_cfg_update| self.update_vm_config(machine_cfg_update))
}
}
}

// Currently, this method is only used for vCPU hotplugging, which is not implemented for
// aarch64, hence we must allow `dead_code`
#[allow(dead_code)]
fn update_vm_config(&mut self, cfg: MachineConfigUpdate) -> Result<VmmData, VmmActionError> {
self.vm_resources
.update_vm_config(&cfg)
.map(|()| VmmData::Empty)
.map_err(VmmActionError::MachineConfig)
}
}

#[cfg(test)]
Expand All @@ -875,8 +900,14 @@ mod tests {
use std::path::PathBuf;

use seccompiler::BpfThreadMap;
#[cfg(target_arch = "x86_64")]
use vmm_config::hotplug::HotplugVcpuError;

use super::*;
// Currently, default_vmm only used for testing hotplugging, which is only implemented for
// x86_64, so `unused_imports` must be allowed for aarch64 systems
#[cfg(target_arch = "x86_64")]
use crate::builder::tests::default_vmm;
use crate::cpu_config::templates::test_utils::build_test_template;
use crate::cpu_config::templates::{CpuTemplateType, StaticCpuTemplate};
use crate::devices::virtio::balloon::{BalloonConfig, BalloonError};
Expand All @@ -885,6 +916,8 @@ mod tests {
use crate::devices::virtio::vsock::VsockError;
use crate::mmds::data_store::MmdsVersion;
use crate::vmm_config::balloon::BalloonBuilder;
#[cfg(target_arch = "x86_64")]
use crate::vmm_config::hotplug::HotplugVcpuConfig;
use crate::vmm_config::machine_config::VmConfig;
use crate::vmm_config::snapshot::{MemBackendConfig, MemBackendType};
use crate::vmm_config::vsock::VsockBuilder;
Expand All @@ -893,27 +926,55 @@ mod tests {
impl PartialEq for VmmActionError {
fn eq(&self, other: &VmmActionError) -> bool {
use VmmActionError::*;
matches!(
(self, other),
(BalloonConfig(_), BalloonConfig(_))
| (BootSource(_), BootSource(_))
| (CreateSnapshot(_), CreateSnapshot(_))
| (DriveConfig(_), DriveConfig(_))
| (InternalVmm(_), InternalVmm(_))
| (LoadSnapshot(_), LoadSnapshot(_))
| (MachineConfig(_), MachineConfig(_))
| (Metrics(_), Metrics(_))
| (Mmds(_), Mmds(_))
| (MmdsLimitExceeded(_), MmdsLimitExceeded(_))
| (MmdsConfig(_), MmdsConfig(_))
| (NetworkConfig(_), NetworkConfig(_))
| (NotSupported(_), NotSupported(_))
| (OperationNotSupportedPostBoot, OperationNotSupportedPostBoot)
| (OperationNotSupportedPreBoot, OperationNotSupportedPreBoot)
| (StartMicrovm(_), StartMicrovm(_))
| (VsockConfig(_), VsockConfig(_))
| (EntropyDevice(_), EntropyDevice(_))
)
#[cfg(target_arch = "x86_64")]
{
matches!(
(self, other),
(BalloonConfig(_), BalloonConfig(_))
| (BootSource(_), BootSource(_))
| (CreateSnapshot(_), CreateSnapshot(_))
| (DriveConfig(_), DriveConfig(_))
| (HotplugRequest(_), HotplugRequest(_))
| (InternalVmm(_), InternalVmm(_))
| (LoadSnapshot(_), LoadSnapshot(_))
| (MachineConfig(_), MachineConfig(_))
| (Metrics(_), Metrics(_))
| (Mmds(_), Mmds(_))
| (MmdsLimitExceeded(_), MmdsLimitExceeded(_))
| (MmdsConfig(_), MmdsConfig(_))
| (NetworkConfig(_), NetworkConfig(_))
| (NotSupported(_), NotSupported(_))
| (OperationNotSupportedPostBoot, OperationNotSupportedPostBoot)
| (OperationNotSupportedPreBoot, OperationNotSupportedPreBoot)
| (StartMicrovm(_), StartMicrovm(_))
| (VsockConfig(_), VsockConfig(_))
| (EntropyDevice(_), EntropyDevice(_))
)
}
#[cfg(target_arch = "aarch64")]
{
matches!(
(self, other),
(BalloonConfig(_), BalloonConfig(_))
| (BootSource(_), BootSource(_))
| (CreateSnapshot(_), CreateSnapshot(_))
| (DriveConfig(_), DriveConfig(_))
| (InternalVmm(_), InternalVmm(_))
| (LoadSnapshot(_), LoadSnapshot(_))
| (MachineConfig(_), MachineConfig(_))
| (Metrics(_), Metrics(_))
| (Mmds(_), Mmds(_))
| (MmdsLimitExceeded(_), MmdsLimitExceeded(_))
| (MmdsConfig(_), MmdsConfig(_))
| (NetworkConfig(_), NetworkConfig(_))
| (NotSupported(_), NotSupported(_))
| (OperationNotSupportedPostBoot, OperationNotSupportedPostBoot)
| (OperationNotSupportedPreBoot, OperationNotSupportedPreBoot)
| (StartMicrovm(_), StartMicrovm(_))
| (VsockConfig(_), VsockConfig(_))
| (EntropyDevice(_), EntropyDevice(_))
)
}
}
}

Expand Down Expand Up @@ -1106,6 +1167,8 @@ mod tests {
pub update_block_device_path_called: bool,
pub update_block_device_vhost_user_config_called: bool,
pub update_net_rate_limiters_called: bool,
#[cfg(target_arch = "x86_64")]
pub hotplug_vcpus_called: bool,
// when `true`, all self methods are forced to fail
pub force_errors: bool,
}
Expand Down Expand Up @@ -1216,6 +1279,24 @@ mod tests {
Ok(())
}

#[cfg(target_arch = "x86_64")]
pub fn hotplug_vcpus(
&mut self,
_: HotplugVcpuConfig,
) -> Result<MachineConfigUpdate, HotplugVcpuError> {
if self.force_errors {
return Err(HotplugVcpuError::VcpuCountTooHigh);
}
self.hotplug_vcpus_called = true;
Ok(MachineConfigUpdate {
vcpu_count: Some(1),
mem_size_mib: None,
smt: None,
cpu_template: None,
track_dirty_pages: None,
huge_pages: None,
})
}
pub fn instance_info(&self) -> InstanceInfo {
InstanceInfo::default()
}
Expand Down Expand Up @@ -1830,6 +1911,12 @@ mod tests {
VmmAction::SendCtrlAltDel,
VmmActionError::OperationNotSupportedPreBoot,
);

#[cfg(target_arch = "x86_64")]
check_preboot_request_err(
VmmAction::HotplugRequest(HotplugRequestConfig::Vcpu(HotplugVcpuConfig { add: 4 })),
VmmActionError::OperationNotSupportedPreBoot,
);
}

fn check_runtime_request<F>(request: VmmAction, check_success: F)
Expand Down Expand Up @@ -2059,6 +2146,44 @@ mod tests {
);
}

#[test]
#[cfg(target_arch = "x86_64")]
fn test_runtime_hotplug_vcpu() {
// Case 1. Valid input
let mut vmm = default_vmm();
let config = HotplugVcpuConfig { add: 4 };
let result = vmm.hotplug_vcpus(config);
assert_eq!(vmm.vcpus_handles.len(), 4);
result.unwrap();

// Case 2. Vcpu count too low
let mut vmm = default_vmm();
vmm.hotplug_vcpus(HotplugVcpuConfig { add: 1 }).unwrap();
assert_eq!(vmm.vcpus_handles.len(), 1);
let config = HotplugVcpuConfig { add: 0 };
let result = vmm.hotplug_vcpus(config);
result.unwrap_err();
assert_eq!(vmm.vcpus_handles.len(), 1);

// Case 3. Vcpu count too high
let mut vmm = default_vmm();
vmm.hotplug_vcpus(HotplugVcpuConfig { add: 1 }).unwrap();
assert_eq!(vmm.vcpus_handles.len(), 1);
let config = HotplugVcpuConfig { add: 33 };
let result = vmm.hotplug_vcpus(config);
result.unwrap_err();
assert_eq!(vmm.vcpus_handles.len(), 1);

// Case 4. Attempted overflow of vcpus
let mut vmm = default_vmm();
vmm.hotplug_vcpus(HotplugVcpuConfig { add: 2 }).unwrap();
assert_eq!(vmm.vcpus_handles.len(), 2);
let config = HotplugVcpuConfig { add: 255 };
let result = vmm.hotplug_vcpus(config);
result.unwrap_err();
assert_eq!(vmm.vcpus_handles.len(), 2);
}

#[test]
fn test_runtime_disallowed() {
check_runtime_request_err(
Expand Down
2 changes: 2 additions & 0 deletions src/vmm/src/vmm_config/hotplug.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,8 @@ pub enum HotplugVcpuError {
VcpuCreate(VcpuError),
/// Failed to start vCPUs
VcpuStart(StartVcpusError),
/// No seccomp filter for thread category: {0}
MissingSeccompFilters(String),
}

/// Config for hotplugging vCPUS
Expand Down

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