Add SMBIOS OEM Strings support (aarch64 only)

Add a new API `krun_set_smbios_oem_strings()` to set SMBIOS
OEM Strings (type 11), and all the internal machinery to
provide them to the firmware. The EDK2 firmware expect the
SMBIOS tables on address 0x4000_F000.

Currently, this is only supported on aarch64 architectures.

Signed-off-by: German Maglione <gmaglione@redhat.com>

include/libkrun.h

@@ -243,6 +243,18 @@ int32_t krun_set_snd_device(uint32_t ctx_id, bool enable);
  */
 int32_t krun_set_rlimits(uint32_t ctx_id, const char *const rlimits[]);
 
+/**
+ * Sets the SMBIOS OEM Strings.
+ *
+ * Arguments:
+ *  "ctx_id"      - the configuration context ID.
+ *  "oem_strings" - an array of string pointers. Must be terminated with an additional NULL pointer.
+ *
+ * Returns:
+ *  Zero on success or a negative error number on failure.
+ */
+int32_t krun_set_smbios_oem_strings(uint32_t ctx_id, const char *const oem_strings[]);
+
 /**
  * Sets the working directory for the executable to be run inside the microVM.
  *

src/arch/Cargo.toml

@@ -14,6 +14,7 @@ libc = ">=0.2.39"
 vm-memory = { version = ">=0.13", features = ["backend-mmap"] }
 
 arch_gen = { path = "../arch_gen" }
+smbios = { path = "../smbios" }
 utils = { path = "../utils" }
 
 [target.'cfg(target_os = "linux")'.dependencies]

src/arch/src/aarch64/layout.rs

@@ -89,3 +89,6 @@ pub const GTIMER_PHYS: u32 = 12;
 pub const MAPPED_IO_START: u64 = 1 << 30; // 1 GB
 #[cfg(feature = "efi")]
 pub const MAPPED_IO_START: u64 = 0x0a00_0000;
+
+#[cfg(feature = "efi")]
+pub const SMBIOS_START: u64 = 0x4000_F000;

src/arch/src/aarch64/mod.rs

@@ -24,13 +24,20 @@ use self::gic::GICDevice;
 use crate::ArchMemoryInfo;
 use vm_memory::{Address, GuestAddress, GuestMemory, GuestMemoryMmap};
 
+#[cfg(feature = "efi")]
+use smbios;
+
 /// Errors thrown while configuring aarch64 system.
 #[derive(Debug)]
 pub enum Error {
     /// Failed to create a Flattened Device Tree for this aarch64 microVM.
     SetupFDT(fdt::Error),
     /// Failed to compute the initrd address.
     InitrdAddress,
+
+    #[cfg(feature = "efi")]
+    /// SMBIOS Error
+    Smbios(smbios::Error),
 }
 
 /// The start of the memory area reserved for MMIO devices.
@@ -80,6 +87,7 @@ pub fn arch_memory_regions(size: usize) -> (ArchMemoryInfo, Vec<(GuestAddress, u
 /// * `device_info` - A hashmap containing the attached devices for building FDT device nodes.
 /// * `gic_device` - The GIC device.
 /// * `initrd` - Information about an optional initrd.
+#[allow(clippy::too_many_arguments)]
 pub fn configure_system<T: DeviceInfoForFDT + Clone + Debug>(
     guest_mem: &GuestMemoryMmap,
     arch_memory_info: &ArchMemoryInfo,
@@ -88,6 +96,7 @@ pub fn configure_system<T: DeviceInfoForFDT + Clone + Debug>(
     device_info: &HashMap<(DeviceType, String), T>,
     gic_device: &Box<dyn GICDevice>,
     initrd: &Option<super::InitrdConfig>,
+    _smbios_oem_strings: &Option<Vec<String>>,
 ) -> super::Result<()> {
     fdt::create_fdt(
         guest_mem,
@@ -99,6 +108,11 @@ pub fn configure_system<T: DeviceInfoForFDT + Clone + Debug>(
         initrd,
     )
     .map_err(Error::SetupFDT)?;
+
+    #[cfg(feature = "efi")]
+    smbios::setup_smbios(guest_mem, layout::SMBIOS_START, _smbios_oem_strings)
+        .map_err(Error::Smbios)?;
+
     Ok(())
 }
 

src/libkrun/src/lib.rs

@@ -891,6 +891,38 @@ pub unsafe extern "C" fn krun_set_console_output(ctx_id: u32, c_filepath: *const
     }
 }
 
+#[allow(clippy::missing_safety_doc)]
+#[no_mangle]
+pub unsafe extern "C" fn krun_set_smbios_oem_strings(
+    ctx_id: u32,
+    oem_strings: *const *const c_char,
+) -> i32 {
+    if oem_strings.is_null() {
+        return -libc::EINVAL;
+    }
+
+    let cstr_ptr_slice = slice::from_raw_parts(oem_strings, MAX_ARGS);
+
+    let mut oem_strings = Vec::new();
+
+    for cstr_ptr in cstr_ptr_slice.iter().take_while(|p| !p.is_null()) {
+        let Ok(s) = CStr::from_ptr(*cstr_ptr).to_str() else {
+            return -libc::EINVAL;
+        };
+        oem_strings.push(s.to_string());
+    }
+
+    match CTX_MAP.lock().unwrap().entry(ctx_id) {
+        Entry::Occupied(mut ctx_cfg) => {
+            ctx_cfg.get_mut().vmr.smbios_oem_strings =
+                (!oem_strings.is_empty()).then_some(oem_strings)
+        }
+        Entry::Vacant(_) => return -libc::ENOENT,
+    }
+
+    KRUN_SUCCESS
+}
+
 #[cfg(feature = "net")]
 fn create_virtio_net(ctx_cfg: &mut ContextConfig, backend: VirtioNetBackend) {
     let mac = if let Some(mac) = ctx_cfg.mac {

src/vmm/src/builder.rs

@@ -638,8 +638,12 @@ pub fn build_microvm(
     #[cfg(not(feature = "tee"))]
     let initrd_config = None;
 
-    vmm.configure_system(vcpus.as_slice(), &initrd_config)
-        .map_err(StartMicrovmError::Internal)?;
+    vmm.configure_system(
+        vcpus.as_slice(),
+        &initrd_config,
+        &vm_resources.smbios_oem_strings,
+    )
+    .map_err(StartMicrovmError::Internal)?;
 
     #[cfg(feature = "tee")]
     {

src/vmm/src/lib.rs

@@ -261,7 +261,12 @@ impl Vmm {
     }
 
     /// Configures the system for boot.
-    pub fn configure_system(&self, vcpus: &[Vcpu], initrd: &Option<InitrdConfig>) -> Result<()> {
+    pub fn configure_system(
+        &self,
+        vcpus: &[Vcpu],
+        initrd: &Option<InitrdConfig>,
+        _smbios_oem_strings: &Option<Vec<String>>,
+    ) -> Result<()> {
         #[cfg(target_arch = "x86_64")]
         {
             let cmdline_len = if cfg!(feature = "tee") {
@@ -292,6 +297,7 @@ impl Vmm {
                 self.mmio_device_manager.get_device_info(),
                 self.vm.get_irqchip(),
                 initrd,
+                _smbios_oem_strings,
             )
             .map_err(Error::ConfigureSystem)?;
         }
@@ -307,6 +313,7 @@ impl Vmm {
                 self.mmio_device_manager.get_device_info(),
                 self.vm.get_irqchip(),
                 initrd,
+                _smbios_oem_strings,
             )
             .map_err(Error::ConfigureSystem)?;
         }

src/vmm/src/resources.rs

@@ -115,6 +115,8 @@ pub struct VmResources {
     pub snd_device: bool,
     /// File to send console output.
     pub console_output: Option<PathBuf>,
+    /// SMBIOS OEM Strings
+    pub smbios_oem_strings: Option<Vec<String>>,
 }
 
 impl VmResources {
@@ -327,6 +329,7 @@ mod tests {
             #[cfg(feature = "snd")]
             enable_snd: False,
             console_output: None,
+            smbios_oem_strings: None,
         }
     }