Removes hard-coded RAM size (#1038)

gui/kvm.cpp

@@ -9,29 +9,6 @@
 #include <stdint.h>
 #include <string.h>
 
-extern "C" int kvm_set_user_memory_region(
-    int vm,
-    uint32_t slot,
-    uint64_t addr,
-    uint64_t len,
-    void *mem)
-{
-    kvm_userspace_memory_region mr;
-
-    memset(&mr, 0, sizeof(mr));
-
-    mr.slot = slot;
-    mr.guest_phys_addr = addr;
-    mr.memory_size = len;
-    mr.userspace_addr = reinterpret_cast<uint64_t>(mem);
-
-    if (ioctl(vm, KVM_SET_USER_MEMORY_REGION, &mr) < 0) {
-        return errno;
-    }
-
-    return 0;
-}
-
 extern "C" int kvm_run(int vcpu)
 {
     return ioctl(vcpu, KVM_RUN, 0);

gui/src/vmm/debug/controller.rs

@@ -92,7 +92,11 @@ impl<T> Debugger<T> {
 
         if matches!(s.deref(), DataState::None) {
             *s = DataState::DebuggerOwned(v);
-            return ResponseHandle(&self.0);
+
+            return ResponseHandle {
+                data: &self.0,
+                taken: false,
+            };
         }
 
         // Once the debugger has been requested the data it will wait for the data and a signal from
@@ -121,27 +125,47 @@ impl<T> Debugger<T> {
         // wake them up. Condvar::notify_one do nothing if there are no any thread waiting on it.
         self.0.signal.notify_one();
 
-        ResponseHandle(&self.0)
+        ResponseHandle {
+            data: &self.0,
+            taken: false,
+        }
     }
 }
 
 /// Provides method to get a response from the debugger.
-pub struct ResponseHandle<'a, T>(&'a Data<T>);
+pub struct ResponseHandle<'a, T> {
+    data: &'a Data<T>,
+    taken: bool,
+}
 
 impl<'a, T> ResponseHandle<'a, T> {
-    pub fn into_response(self) -> T {
-        let mut s = self.0.state.lock().unwrap();
+    pub fn into_response(mut self) -> T {
+        let mut s = self.data.state.lock().unwrap();
         let v = match std::mem::take(s.deref_mut()) {
             DataState::DebuggeeOwned(v) => v,
             _ => panic!("the debugger did not release the data"),
         };
 
+        self.taken = true;
+
+        v
+    }
+}
+
+impl<'a, T> Drop for ResponseHandle<'a, T> {
+    fn drop(&mut self) {
+        if !self.taken {
+            let mut s = self.data.state.lock().unwrap();
+
+            if !matches!(std::mem::take(s.deref_mut()), DataState::DebuggeeOwned(_)) {
+                panic!("the debugger did not release the data");
+            }
+        }
+
         // It is possible for this method to get called after the debugger has reacquired the lock
         // so we need to wake them up. Condvar::notify_one do nothing if there are no any thread
         // waiting on it.
-        self.0.signal.notify_one();
-
-        v
+        self.data.signal.notify_one();
     }
 }
 

gui/src/vmm/hv/linux/ffi.rs

@@ -1,10 +1,11 @@
-use std::ffi::{c_int, c_ulong, c_void};
+use std::ffi::{c_int, c_ulong};
 
 pub const KVM_GET_API_VERSION: c_ulong = _IO(KVMIO, 0x00);
 pub const KVM_CREATE_VM: c_ulong = _IO(KVMIO, 0x01);
 pub const KVM_CHECK_EXTENSION: c_ulong = _IO(KVMIO, 0x03);
 pub const KVM_GET_VCPU_MMAP_SIZE: c_ulong = _IO(KVMIO, 0x04);
 pub const KVM_CREATE_VCPU: c_ulong = _IO(KVMIO, 0x41);
+pub const KVM_SET_USER_MEMORY_REGION: c_ulong = _IOW::<KvmUserspaceMemoryRegion>(KVMIO, 0x46);
 #[cfg(target_arch = "aarch64")]
 pub const KVM_GET_ONE_REG: c_ulong = _IOW::<KvmOneReg<()>>(KVMIO, 0xab);
 #[cfg(target_arch = "aarch64")]
@@ -78,6 +79,15 @@ const fn _IOC(dir: c_ulong, ty: c_ulong, nr: c_ulong, size: c_ulong) -> c_ulong
         | (size << _IOC_SIZESHIFT)
 }
 
+#[repr(C)]
+pub struct KvmUserspaceMemoryRegion {
+    pub slot: u32,
+    pub flags: u32,
+    pub guest_phys_addr: u64,
+    pub memory_size: u64,
+    pub userspace_addr: u64,
+}
+
 #[cfg(target_arch = "aarch64")]
 #[repr(C)]
 pub struct KvmOneReg<'a, T> {
@@ -93,12 +103,5 @@ pub struct KvmVcpuInit {
 }
 
 extern "C" {
-    pub fn kvm_set_user_memory_region(
-        vm: c_int,
-        slot: u32,
-        addr: u64,
-        len: u64,
-        mem: *mut c_void,
-    ) -> c_int;
     pub fn kvm_run(vcpu: c_int) -> c_int;
 }

gui/src/vmm/hv/linux/mod.rs

@@ -1,8 +1,9 @@
 // SPDX-License-Identifier: MIT OR Apache-2.0
 use self::cpu::KvmCpu;
 use self::ffi::{
-    kvm_set_user_memory_region, KVM_API_VERSION, KVM_CAP_MAX_VCPUS, KVM_CHECK_EXTENSION,
+    KvmUserspaceMemoryRegion, KVM_API_VERSION, KVM_CAP_MAX_VCPUS, KVM_CHECK_EXTENSION,
     KVM_CREATE_VCPU, KVM_CREATE_VM, KVM_GET_API_VERSION, KVM_GET_VCPU_MMAP_SIZE,
+    KVM_SET_USER_MEMORY_REGION,
 };
 use super::{CpuFeats, Hypervisor};
 use crate::vmm::ram::Ram;
@@ -81,13 +82,16 @@ pub fn new(cpu: usize, ram: Ram) -> Result<Kvm, VmmError> {
     };
 
     // Set RAM.
-    let slot = 0;
-    let len = ram.len().try_into().unwrap();
-    let mem = ram.host_addr().cast_mut().cast();
+    let mr = KvmUserspaceMemoryRegion {
+        slot: 0,
+        flags: 0,
+        guest_phys_addr: 0,
+        memory_size: ram.len().get().try_into().unwrap(),
+        userspace_addr: (ram.host_addr() as usize).try_into().unwrap(),
+    };
 
-    match unsafe { kvm_set_user_memory_region(vm.as_raw_fd(), slot, 0, len, mem) } {
-        0 => {}
-        v => return Err(VmmError::MapRamFailed(Error::from_raw_os_error(v))),
+    if unsafe { ioctl(vm.as_raw_fd(), KVM_SET_USER_MEMORY_REGION, &mr) } < 0 {
+        return Err(VmmError::MapRamFailed(Error::last_os_error()));
     }
 
     // AArch64 require all CPU to be created before calling KVM_ARM_VCPU_INIT.

gui/src/vmm/hv/macos/mod.rs

@@ -46,7 +46,7 @@ pub fn new(_: usize, ram: Ram) -> Result<Hvf, VmmError> {
 
     // Set RAM.
     let host = hv.ram.host_addr().cast_mut().cast();
-    let len = hv.ram.len().try_into().unwrap();
+    let len = hv.ram.len().get().try_into().unwrap();
     let ret = unsafe {
         hv_vm_map(
             host,

gui/src/vmm/hv/windows/mod.rs

@@ -19,7 +19,11 @@ pub fn new(cpu: usize, ram: Ram) -> Result<Whp, VmmError> {
     part.setup().map_err(VmmError::SetupPartitionFailed)?;
 
     // Map memory.
-    part.map_gpa(ram.host_addr().cast(), 0, ram.len().try_into().unwrap())
+    part.map_gpa(
+        ram.host_addr().cast(),
+        0,
+        ram.len().get().try_into().unwrap(),
+    )
     .map_err(VmmError::MapRamFailed)?;
 
     Ok(Whp {

gui/src/vmm/mod.rs

@@ -329,7 +329,7 @@ pub unsafe extern "C" fn vmm_start(
     };
 
     // Setup RAM.
-    let ram = match Ram::new(block_size) {
+    let ram = match Ram::new(NonZero::new(1024 * 1024 * 1024 * 8).unwrap(), block_size) {
         Ok(v) => v,
         Err(e) => {
             *err = RustError::with_source("couldn't create a RAM", e).into_c();
@@ -337,6 +337,10 @@ pub unsafe extern "C" fn vmm_start(
         }
     };
 
+    // Setup virtual devices.
+    let event = VmmEventHandler { fp: event, cx };
+    let devices = Arc::new(setup_devices(ram.len().get(), block_size, event));
+
     // Setup hypervisor.
     let mut hv = match self::hv::new(8, ram) {
         Ok(v) => v,
@@ -401,8 +405,6 @@ pub unsafe extern "C" fn vmm_start(
     }
 
     // Allocate arguments.
-    let event = VmmEventHandler { fp: event, cx };
-    let devices = Arc::new(setup_devices(Ram::SIZE, block_size, event));
     let env = BootEnv::Vm(Vm {
         vmm: devices.vmm().addr(),
         console: devices.console().addr(),

gui/src/vmm/ram/mod.rs

@@ -16,15 +16,14 @@ mod builder;
 /// RAM always started at address 0.
 pub struct Ram {
     mem: *mut u8,
+    len: NonZero<usize>,
     block_size: NonZero<usize>,
 }
 
 impl Ram {
-    pub(crate) const SIZE: usize = 1024 * 1024 * 1024 * 8; // 8GB
-
     /// # Safety
     /// `block_size` must be greater or equal host page size.
-    pub unsafe fn new(block_size: NonZero<usize>) -> Result<Self, Error> {
+    pub unsafe fn new(len: NonZero<usize>, block_size: NonZero<usize>) -> Result<Self, Error> {
         use std::io::Error;
 
         // Reserve memory range.
@@ -35,7 +34,7 @@ impl Ram {
 
             let mem = mmap(
                 null_mut(),
-                Self::SIZE,
+                len.get(),
                 PROT_NONE,
                 MAP_PRIVATE | MAP_ANON,
                 -1,
@@ -54,7 +53,7 @@ impl Ram {
             use std::ptr::null;
             use windows_sys::Win32::System::Memory::{VirtualAlloc, MEM_RESERVE, PAGE_NOACCESS};
 
-            let mem = VirtualAlloc(null(), Self::SIZE, MEM_RESERVE, PAGE_NOACCESS);
+            let mem = VirtualAlloc(null(), len.get(), MEM_RESERVE, PAGE_NOACCESS);
 
             if mem.is_null() {
                 return Err(Error::last_os_error());
@@ -63,15 +62,19 @@ impl Ram {
             mem.cast()
         };
 
-        Ok(Self { mem, block_size })
+        Ok(Self {
+            mem,
+            len,
+            block_size,
+        })
     }
 
     pub fn host_addr(&self) -> *const u8 {
         self.mem
     }
 
-    pub fn len(&self) -> usize {
-        Self::SIZE
+    pub fn len(&self) -> NonZero<usize> {
+        self.len
     }
 
     pub fn builder(&mut self) -> RamBuilder {
@@ -88,7 +91,10 @@ impl Ram {
         assert_eq!(addr % self.block_size, 0);
         assert_eq!(len.get() % self.block_size, 0);
 
-        if !addr.checked_add(len.get()).is_some_and(|v| v <= Self::SIZE) {
+        if !addr
+            .checked_add(len.get())
+            .is_some_and(|v| v <= self.len.get())
+        {
             return Err(RamError::InvalidAddr);
         }
 
@@ -106,7 +112,10 @@ impl Ram {
         assert_eq!(addr % self.block_size, 0);
         assert_eq!(len.get() % self.block_size, 0);
 
-        if !addr.checked_add(len.get()).is_some_and(|v| v <= Self::SIZE) {
+        if !addr
+            .checked_add(len.get())
+            .is_some_and(|v| v <= self.len.get())
+        {
             return Err(RamError::InvalidAddr);
         }
 
@@ -174,7 +183,7 @@ impl Drop for Ram {
     fn drop(&mut self) {
         use libc::munmap;
 
-        if unsafe { munmap(self.mem.cast(), Self::SIZE) } < 0 {
+        if unsafe { munmap(self.mem.cast(), self.len.get()) } < 0 {
             panic!(
                 "failed to unmap RAM at {:p}: {}",
                 self.mem,