minimal KVM abstraction + real mode guest example

1 files changed, 45 insertions, 0 deletions

diff --git a/src/vm.rs b/src/vm.rs
new file mode 100644
index 0000000..6f8a355
--- /dev/null
+++ b/src/vm.rs
@@ -0,0 +1,45 @@
+use std::fs;
+use std::io;
+use std::os::unix::io::FromRawFd;
+
+use crate::vcpu::Vcpu;
+use crate::{ioctl, kvm_sys, KvmRun, PhysAddr, UserMem};
+
+pub struct Vm {
+    vm: fs::File,
+    vcpu_mmap_size: usize,
+}
+
+impl Vm {
+    pub(crate) fn new(vm: fs::File, vcpu_mmap_size: usize) -> Vm {
+        Vm { vm, vcpu_mmap_size }
+    }
+
+    pub unsafe fn set_user_memory_region(
+        &self,
+        phys_addr: PhysAddr,
+        mem: &UserMem,
+    ) -> io::Result<()> {
+        // Create guest physical memory mapping for `slot : 0` at guest `phys addr : 0`.
+        let mut kvm_mem = kvm_sys::kvm_userspace_memory_region::default();
+        kvm_mem.userspace_addr = mem.ptr as u64;
+        kvm_mem.memory_size = mem.len as u64;
+        kvm_mem.guest_phys_addr = phys_addr.0;
+
+        ioctl(
+            &self.vm,
+            kvm_sys::KVM_SET_USER_MEMORY_REGION,
+            &kvm_mem as *const _ as u64,
+        )
+        .map(|_| ())
+    }
+
+    pub fn create_vpcu(&self, id: u64) -> io::Result<Vcpu> {
+        let vcpu = ioctl(&self.vm, kvm_sys::KVM_CREATE_VCPU, id)
+            .map(|fd| unsafe { fs::File::from_raw_fd(fd) })?;
+
+        let kvm_run = KvmRun::new(&vcpu, self.vcpu_mmap_size)?;
+
+        Ok(Vcpu::new(vcpu, kvm_run))
+    }
+}