vfio: Use the vfio-binding FAM wrappers

It's less unsafe and makes the code more readable.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

Cargo.lock

@@ -1040,7 +1040,7 @@ dependencies = [
  "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "pci 0.1.0",
- "vfio-bindings 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "vfio-bindings 0.1.0 (git+https://github.com/rust-vmm/vfio-bindings)",
  "vm-allocator 0.1.0",
  "vm-device 0.1.0",
  "vm-memory 0.1.0 (git+https://github.com/rust-vmm/vm-memory)",
@@ -1050,9 +1050,9 @@ dependencies = [
 [[package]]
 name = "vfio-bindings"
 version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
+source = "git+https://github.com/rust-vmm/vfio-bindings#46ef9d418e8d75b6a4b96f3bbc04e6eb47fef54b"
 dependencies = [
- "vmm-sys-util 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "vmm-sys-util 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1219,14 +1219,6 @@ dependencies = [
  "vmm-sys-util 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "vmm-sys-util"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "vmm-sys-util"
 version = "0.4.0"
@@ -1392,11 +1384,10 @@ dependencies = [
 "checksum utf8-ranges 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "b4ae116fef2b7fea257ed6440d3cfcff7f190865f170cdad00bb6465bf18ecba"
 "checksum vcpkg 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "3fc439f2794e98976c88a2a2dafce96b930fe8010b0a256b3c2199a773933168"
 "checksum vec_map 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "05c78687fb1a80548ae3250346c3db86a80a7cdd77bda190189f2d0a0987c81a"
-"checksum vfio-bindings 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "df0379abaedb35cac2636dd2ee75496ab921430fa5775b90f13bbda3e2abaf66"
+"checksum vfio-bindings 0.1.0 (git+https://github.com/rust-vmm/vfio-bindings)" = "<none>"
 "checksum virtio-bindings 0.1.0 (git+https://github.com/rust-vmm/virtio-bindings)" = "<none>"
 "checksum virtio-bindings 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3ff512178285488516ed85f15b5d0113a7cdb89e9e8a760b269ae4f02b84bd6b"
 "checksum vm-memory 0.1.0 (git+https://github.com/rust-vmm/vm-memory)" = "<none>"
-"checksum vmm-sys-util 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "46996f56aeae31fbc0532ae57a944e00089302f03b18c10c76eebfd9249f4a6c"
 "checksum vmm-sys-util 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "048b10a74f061d87dacca196a1964052a7135651641ab8d100aef21e58f33571"
 "checksum wasi 0.9.0+wasi-snapshot-preview1 (registry+https://github.com/rust-lang/crates.io-index)" = "cccddf32554fecc6acb585f82a32a72e28b48f8c4c1883ddfeeeaa96f7d8e519"
 "checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"

vfio/Cargo.toml

@@ -12,7 +12,6 @@ kvm-ioctls = "0.5.0"
 libc = "0.2.60"
 log = "0.4.8"
 pci = { path = "../pci" }
-vfio-bindings = "0.1.0"
 vm-allocator = { path = "../vm-allocator" }
 vm-device = { path = "../vm-device" }
 vmm-sys-util = ">=0.3.1"
@@ -20,3 +19,7 @@ vmm-sys-util = ">=0.3.1"
 [dependencies.vm-memory]
 git = "https://github.com/rust-vmm/vm-memory"
 features = ["backend-mmap"]
+
+[dependencies.vfio-bindings]
+git = "https://github.com/rust-vmm/vfio-bindings"
+features = ["fam-wrappers"]

vfio/src/vfio_device.rs

@@ -21,10 +21,12 @@ use std::result;
 use std::sync::Arc;
 use std::u32;
 use vfio_bindings::bindings::vfio::*;
+use vfio_bindings::bindings::IrqSet;
 use vfio_ioctls::*;
 use vm_device::{get_host_address_range, ExternalDmaMapping};
 use vm_memory::{Address, GuestAddress, GuestMemory, GuestMemoryMmap, GuestMemoryRegion};
 use vmm_sys_util::eventfd::EventFd;
+use vmm_sys_util::fam::FamStruct;
 use vmm_sys_util::ioctl::*;
 
 #[derive(Debug)]
@@ -645,34 +647,25 @@ impl VfioDevice {
             return Err(VfioError::VfioDeviceSetIrq);
         }
 
-        let mut irq_set = vec_with_array_field::<vfio_irq_set, u32>(event_fds.len());
-        irq_set[0].argsz = mem::size_of::<vfio_irq_set>() as u32
-            + (event_fds.len() * mem::size_of::<u32>()) as u32;
-        irq_set[0].flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER;
-        irq_set[0].index = irq_index;
-        irq_set[0].start = 0;
-        irq_set[0].count = irq.count;
+        let mut irq_set_wrapper = IrqSet::new(event_fds.len() * mem::size_of::<u32>());
+        let mut irq_set = irq_set_wrapper.as_mut_fam_struct();
+        let fds = irq_set.as_mut_slice();
 
-        {
-            // irq_set.data could be none, bool or fd according to flags, so irq_set.data
-            // is u8 default, here irq_set.data is a vector of fds as u32, so 4 default u8
-            // are combined together as u32 for each fd.
-            // It is safe as enough space is reserved through
-            // vec_with_array_field(u32)<event_fds.len()>.
-            let fds = unsafe {
-                irq_set[0]
-                    .data
-                    .as_mut_slice(event_fds.len() * mem::size_of::<u32>())
-            };
-            for (index, event_fd) in event_fds.iter().enumerate() {
-                let fds_offset = index * mem::size_of::<u32>();
-                let fd = &mut fds[fds_offset..fds_offset + mem::size_of::<u32>()];
-                LittleEndian::write_u32(fd, event_fd.as_raw_fd() as u32);
-            }
+        for (index, event_fd) in event_fds.iter().enumerate() {
+            let fds_offset = index * mem::size_of::<u32>();
+            let fd = &mut fds[fds_offset..fds_offset + mem::size_of::<u32>()];
+            LittleEndian::write_u32(fd, event_fd.as_raw_fd() as u32);
         }
 
+        irq_set.argsz = mem::size_of::<vfio_irq_set>() as u32
+            + (event_fds.len() * mem::size_of::<u32>()) as u32;
+        irq_set.flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER;
+        irq_set.index = irq_index;
+        irq_set.start = 0;
+        irq_set.count = irq.count;
+
         // Safe as we are the owner of self and irq_set which are valid value
-        let ret = unsafe { ioctl_with_ref(self, VFIO_DEVICE_SET_IRQS(), &irq_set[0]) };
+        let ret = unsafe { ioctl_with_ref(self, VFIO_DEVICE_SET_IRQS(), irq_set) };
         if ret < 0 {
             return Err(VfioError::VfioDeviceSetIrq);
         }