feature(xen): implement power management operations (#215)

crates/xen/xencall/Cargo.toml

@@ -33,3 +33,7 @@ path = "examples/domain_create.rs"
 [[example]]
 name = "xencall-version-capabilities"
 path = "examples/version_capabilities.rs"
+
+[[example]]
+name = "xencall-power-management"
+path = "examples/power_management.rs"

crates/xen/xencall/examples/power_management.rs

@@ -0,0 +1,19 @@
+use xencall::error::Result;
+use xencall::sys::CpuId;
+use xencall::XenCall;
+
+#[tokio::main]
+async fn main() -> Result<()> {
+    env_logger::init();
+
+    let call = XenCall::open(0)?;
+    let physinfo = call.phys_info().await?;
+    println!("{:?}", physinfo);
+    let topology = call.cpu_topology().await?;
+    println!("{:?}", topology);
+    call.set_cpufreq_gov(CpuId::All, "performance").await?;
+    call.set_cpufreq_gov(CpuId::Single(0), "performance")
+        .await?;
+    call.set_turbo_mode(CpuId::All, true).await?;
+    Ok(())
+}

crates/xen/xencall/src/error.rs

@@ -14,6 +14,8 @@ pub enum Error {
     PopulatePhysmapFailed,
     #[error("mmap batch failed: {0}")]
     MmapBatchFailed(nix::errno::Errno),
+    #[error("specified value is too long")]
+    ValueTooLong,
 }
 
 pub type Result<T> = std::result::Result<T, Error>;

crates/xen/xencall/src/lib.rs

@@ -25,9 +25,13 @@ use std::ffi::{c_long, c_uint, c_ulong, c_void};
 use std::sync::Arc;
 use std::time::Duration;
 use sys::{
-    E820Entry, ForeignMemoryMap, PhysdevMapPirq, VcpuGuestContextAny, HYPERVISOR_PHYSDEV_OP,
-    PHYSDEVOP_MAP_PIRQ, XEN_DOMCTL_MAX_INTERFACE_VERSION, XEN_DOMCTL_MIN_INTERFACE_VERSION,
-    XEN_MEM_SET_MEMORY_MAP,
+    CpuId, E820Entry, ForeignMemoryMap, PhysdevMapPirq, Sysctl, SysctlCputopo, SysctlCputopoinfo,
+    SysctlPhysinfo, SysctlPmOp, SysctlPmOpValue, SysctlSetCpuFreqGov, SysctlValue,
+    VcpuGuestContextAny, HYPERVISOR_PHYSDEV_OP, HYPERVISOR_SYSCTL, PHYSDEVOP_MAP_PIRQ,
+    XEN_DOMCTL_MAX_INTERFACE_VERSION, XEN_DOMCTL_MIN_INTERFACE_VERSION, XEN_MEM_SET_MEMORY_MAP,
+    XEN_SYSCTL_CPUTOPOINFO, XEN_SYSCTL_MAX_INTERFACE_VERSION, XEN_SYSCTL_MIN_INTERFACE_VERSION,
+    XEN_SYSCTL_PHYSINFO, XEN_SYSCTL_PM_OP, XEN_SYSCTL_PM_OP_DISABLE_TURBO,
+    XEN_SYSCTL_PM_OP_ENABLE_TURBO,
 };
 use tokio::sync::Semaphore;
 use tokio::time::sleep;
@@ -42,6 +46,7 @@ pub struct XenCall {
     pub handle: Arc<File>,
     semaphore: Arc<Semaphore>,
     domctl_interface_version: u32,
+    sysctl_interface_version: u32,
 }
 
 impl XenCall {
@@ -52,10 +57,12 @@ impl XenCall {
             .open("/dev/xen/privcmd")?;
         let domctl_interface_version =
             XenCall::detect_domctl_interface_version(&handle, current_domid)?;
+        let sysctl_interface_version = XenCall::detect_sysctl_interface_version(&handle)?;
         Ok(XenCall {
             handle: Arc::new(handle),
             semaphore: Arc::new(Semaphore::new(1)),
             domctl_interface_version,
+            sysctl_interface_version,
         })
     }
 
@@ -83,6 +90,32 @@ impl XenCall {
         Err(Error::XenVersionUnsupported)
     }
 
+    fn detect_sysctl_interface_version(handle: &File) -> Result<u32> {
+        for version in XEN_SYSCTL_MIN_INTERFACE_VERSION..XEN_SYSCTL_MAX_INTERFACE_VERSION + 1 {
+            let mut sysctl = Sysctl {
+                cmd: XEN_SYSCTL_CPUTOPOINFO,
+                interface_version: version,
+                value: SysctlValue {
+                    cputopoinfo: SysctlCputopoinfo {
+                        num_cpus: 0,
+                        handle: null_mut(),
+                    },
+                },
+            };
+            unsafe {
+                let mut call = Hypercall {
+                    op: HYPERVISOR_SYSCTL,
+                    arg: [addr_of_mut!(sysctl) as u64, 0, 0, 0, 0],
+                };
+                let result = sys::hypercall(handle.as_raw_fd(), &mut call).unwrap_or(-1);
+                if result == 0 {
+                    return Ok(version);
+                }
+            }
+        }
+        Err(Error::XenVersionUnsupported)
+    }
+
     pub async fn mmap(&self, addr: u64, len: u64) -> Option<u64> {
         let _permit = self.semaphore.acquire().await.ok()?;
         trace!(
@@ -917,4 +950,141 @@ impl XenCall {
             .await?;
         Ok(())
     }
+
+    pub async fn cpu_topology(&self) -> Result<Vec<SysctlCputopo>> {
+        let mut sysctl = Sysctl {
+            cmd: XEN_SYSCTL_CPUTOPOINFO,
+            interface_version: self.sysctl_interface_version,
+            value: SysctlValue {
+                cputopoinfo: SysctlCputopoinfo {
+                    num_cpus: 0,
+                    handle: null_mut(),
+                },
+            },
+        };
+        self.hypercall1(HYPERVISOR_SYSCTL, addr_of_mut!(sysctl) as c_ulong)
+            .await?;
+        let cpus = unsafe { sysctl.value.cputopoinfo.num_cpus };
+        let mut topos = vec![
+            SysctlCputopo {
+                core: 0,
+                socket: 0,
+                node: 0
+            };
+            cpus as usize
+        ];
+        let mut sysctl = Sysctl {
+            cmd: XEN_SYSCTL_CPUTOPOINFO,
+            interface_version: self.sysctl_interface_version,
+            value: SysctlValue {
+                cputopoinfo: SysctlCputopoinfo {
+                    num_cpus: cpus,
+                    handle: topos.as_mut_ptr(),
+                },
+            },
+        };
+        self.hypercall1(HYPERVISOR_SYSCTL, addr_of_mut!(sysctl) as c_ulong)
+            .await?;
+        Ok(topos)
+    }
+
+    pub async fn phys_info(&self) -> Result<SysctlPhysinfo> {
+        let mut sysctl = Sysctl {
+            cmd: XEN_SYSCTL_PHYSINFO,
+            interface_version: self.sysctl_interface_version,
+            value: SysctlValue {
+                phys_info: SysctlPhysinfo::default(),
+            },
+        };
+        self.hypercall1(HYPERVISOR_SYSCTL, addr_of_mut!(sysctl) as c_ulong)
+            .await?;
+        Ok(unsafe { sysctl.value.phys_info })
+    }
+
+    pub async fn set_cpufreq_gov(&self, cpuid: CpuId, gov: impl AsRef<str>) -> Result<()> {
+        match cpuid {
+            CpuId::All => {
+                let phys_info = self.phys_info().await?;
+                for cpuid in 0..phys_info.max_cpu_id + 1 {
+                    self.do_set_cpufreq_gov(cpuid, gov.as_ref()).await?;
+                }
+            }
+
+            CpuId::Single(id) => {
+                self.do_set_cpufreq_gov(id, gov).await?;
+            }
+        }
+        Ok(())
+    }
+
+    async fn do_set_cpufreq_gov(&self, cpuid: u32, gov: impl AsRef<str>) -> Result<()> {
+        let governor = gov.as_ref().as_bytes().to_vec();
+        if governor.len() > 15 {
+            return Err(Error::ValueTooLong);
+        }
+
+        let mut scaling_governor = [0u8; 16];
+
+        // leave space for the last byte to be zero at all times.
+        for i in 0..15usize {
+            if i >= governor.len() {
+                break;
+            }
+            scaling_governor[i] = governor[i];
+        }
+
+        let mut sysctl = Sysctl {
+            cmd: XEN_SYSCTL_PM_OP,
+            interface_version: self.sysctl_interface_version,
+            value: SysctlValue {
+                pm_op: SysctlPmOp {
+                    cmd: XEN_SYSCTL_PM_OP_ENABLE_TURBO,
+                    cpuid,
+                    value: SysctlPmOpValue {
+                        set_gov: SysctlSetCpuFreqGov { scaling_governor },
+                    },
+                },
+            },
+        };
+        self.hypercall1(HYPERVISOR_SYSCTL, addr_of_mut!(sysctl) as c_ulong)
+            .await?;
+        Ok(())
+    }
+
+    pub async fn set_turbo_mode(&self, cpuid: CpuId, enable: bool) -> Result<()> {
+        match cpuid {
+            CpuId::All => {
+                let phys_info = self.phys_info().await?;
+                for cpuid in 0..phys_info.max_cpu_id + 1 {
+                    self.do_set_turbo_mode(cpuid, enable).await?;
+                }
+            }
+
+            CpuId::Single(id) => {
+                self.do_set_turbo_mode(id, enable).await?;
+            }
+        }
+        Ok(())
+    }
+
+    async fn do_set_turbo_mode(&self, cpuid: u32, enable: bool) -> Result<()> {
+        let mut sysctl = Sysctl {
+            cmd: XEN_SYSCTL_PM_OP,
+            interface_version: self.sysctl_interface_version,
+            value: SysctlValue {
+                pm_op: SysctlPmOp {
+                    cmd: if enable {
+                        XEN_SYSCTL_PM_OP_ENABLE_TURBO
+                    } else {
+                        XEN_SYSCTL_PM_OP_DISABLE_TURBO
+                    },
+                    cpuid,
+                    value: SysctlPmOpValue { pad: [0u8; 128] },
+                },
+            },
+        };
+        self.hypercall1(HYPERVISOR_SYSCTL, addr_of_mut!(sysctl) as c_ulong)
+            .await?;
+        Ok(())
+    }
 }

crates/xen/xencall/src/sys.rs

@@ -712,3 +712,92 @@ pub struct HvmContext {
 pub struct PagingMempool {
     pub size: u64,
 }
+
+#[repr(C)]
+#[derive(Clone, Copy, Debug)]
+pub struct SysctlCputopo {
+    pub core: u32,
+    pub socket: u32,
+    pub node: u32,
+}
+
+#[repr(C)]
+#[derive(Clone, Copy, Debug)]
+pub struct SysctlSetCpuFreqGov {
+    pub scaling_governor: [u8; 16],
+}
+
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub union SysctlPmOpValue {
+    pub set_gov: SysctlSetCpuFreqGov,
+    pub opt_smt: u32,
+    pub pad: [u8; 128],
+}
+
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub struct SysctlPmOp {
+    pub cmd: u32,
+    pub cpuid: u32,
+    pub value: SysctlPmOpValue,
+}
+
+#[repr(C)]
+#[derive(Clone, Copy, Debug)]
+pub struct SysctlCputopoinfo {
+    pub num_cpus: u32,
+    pub handle: *mut SysctlCputopo,
+}
+
+#[repr(C)]
+pub union SysctlValue {
+    pub cputopoinfo: SysctlCputopoinfo,
+    pub pm_op: SysctlPmOp,
+    pub phys_info: SysctlPhysinfo,
+    pub pad: [u8; 128],
+}
+
+#[repr(C)]
+pub struct Sysctl {
+    pub cmd: u32,
+    pub interface_version: u32,
+    pub value: SysctlValue,
+}
+
+pub const XEN_SYSCTL_PHYSINFO: u32 = 3;
+pub const XEN_SYSCTL_PM_OP: u32 = 12;
+pub const XEN_SYSCTL_CPUTOPOINFO: u32 = 16;
+
+pub const XEN_SYSCTL_MIN_INTERFACE_VERSION: u32 = 0x00000015;
+pub const XEN_SYSCTL_MAX_INTERFACE_VERSION: u32 = 0x00000020;
+pub const XEN_SYSCTL_PM_OP_SET_SCHED_OPT_STMT: u32 = 0x21;
+pub const XEN_SYSCTL_PM_OP_ENABLE_TURBO: u32 = 0x26;
+pub const XEN_SYSCTL_PM_OP_DISABLE_TURBO: u32 = 0x27;
+
+#[derive(Clone, Copy, Debug)]
+pub enum CpuId {
+    All,
+    Single(u32),
+}
+
+#[repr(C)]
+#[derive(Clone, Copy, Debug, Default)]
+pub struct SysctlPhysinfo {
+    pub threads_per_core: u32,
+    pub cores_per_socket: u32,
+    pub nr_cpus: u32,
+    pub max_cpu_id: u32,
+    pub nr_nodes: u32,
+    pub max_node_id: u32,
+    pub cpu_khz: u32,
+    pub capabilities: u32,
+    pub arch_capabilities: u32,
+    pub pad: u32,
+    pub total_pages: u64,
+    pub free_pages: u64,
+    pub scrub_pages: u64,
+    pub outstanding_pages: u64,
+    pub max_mfn: u64,
+    pub hw_cap: [u32; 8],
+}