feat(acpi): add RSDP discovery from BIOS memory regions.

kernel/Cargo.toml

@@ -36,8 +36,8 @@ fifo_demo = []
 
 # 运行时依赖项
 [dependencies]
-acpi = { git = "https://git.mirrors.dragonos.org.cn/DragonOS-Community/acpi-rs.git", rev = "282df2af7b" }
-aml = { git = "https://git.mirrors.dragonos.org.cn/DragonOS-Community/acpi-rs.git", rev = "282df2af7b" }
+acpi = { git = "https://git.mirrors.dragonos.org.cn/DragonOS-Community/acpi-rs.git", rev = "1bbdc9767ac72725fa7bdbc53260b5b6baa2bce1" }
+aml = { git = "https://git.mirrors.dragonos.org.cn/DragonOS-Community/acpi-rs.git", rev = "1bbdc9767ac72725fa7bdbc53260b5b6baa2bce1" }
 asm_macros = { path = "crates/asm_macros" }
 atomic_enum = "=0.2.0"
 bit_field = "=0.10"

kernel/src/arch/x86_64/init/mod.rs

@@ -27,6 +27,7 @@ use super::{
 mod boot;
 mod multiboot2;
 mod pvh;
+mod rsdp;
 
 mod boot_params;
 

kernel/src/arch/x86_64/init/multiboot2.rs

@@ -22,12 +22,23 @@ use crate::{
     mm::{memblock::mem_block_manager, PhysAddr},
 };
 
+use super::rsdp::{cache_bios_rsdp_result, cached_bios_rsdp};
+
 pub(super) const MULTIBOOT2_ENTRY_MAGIC: u32 = multiboot2::MAGIC;
 static MB2_INFO: Lazy<BootInformation> = Lazy::new();
 const MB2_RAW_INFO_MAX_SIZE: usize = 4096;
 
 static mut MB2_RAW_INFO: [u8; MB2_RAW_INFO_MAX_SIZE] = [0u8; MB2_RAW_INFO_MAX_SIZE];
 
+fn has_efi_context(boot_info: &BootInformation) -> bool {
+    boot_info.efi_sdt32_tag().is_some()
+        || boot_info.efi_sdt64_tag().is_some()
+        || boot_info.efi_memory_map_tag().is_some()
+        || boot_info.efi_bs_not_exited_tag().is_some()
+        || boot_info.efi_ih32_tag().is_some()
+        || boot_info.efi_ih64_tag().is_some()
+}
+
 fn mb2_rsdp_v1_tag_to_rsdp_struct(tag: &RsdpV1Tag) -> Rsdp {
     Rsdp {
         signature: tag.signature,
@@ -70,17 +81,23 @@ impl BootCallbacks for Mb2Callback {
     }
 
     fn init_acpi_args(&self) -> Result<BootloaderAcpiArg, SystemError> {
-        if let Some(v1_tag) = MB2_INFO.get().rsdp_v1_tag() {
-            Ok(BootloaderAcpiArg::Rsdt(mb2_rsdp_v1_tag_to_rsdp_struct(
-                v1_tag,
-            )))
-        } else if let Some(v2_tag) = MB2_INFO.get().rsdp_v2_tag() {
-            Ok(BootloaderAcpiArg::Xsdt(mb2_rsdp_v2_tag_to_rsdp_struct(
+        let boot_info = MB2_INFO.get();
+        if let Some(v2_tag) = boot_info.rsdp_v2_tag() {
+            return Ok(BootloaderAcpiArg::Xsdt(mb2_rsdp_v2_tag_to_rsdp_struct(
                 v2_tag,
-            )))
-        } else {
-            Ok(BootloaderAcpiArg::NotProvided)
+            )));
+        }
+        if let Some(v1_tag) = boot_info.rsdp_v1_tag() {
+            return Ok(BootloaderAcpiArg::Rsdt(mb2_rsdp_v1_tag_to_rsdp_struct(
+                v1_tag,
+            )));
+        }
+        if let Some(paddr) = cached_bios_rsdp()? {
+            log::info!("multiboot2: found RSDP at {:#x}", paddr.data());
+            return Ok(BootloaderAcpiArg::Rsdp(paddr));
         }
+
+        Ok(BootloaderAcpiArg::NotProvided)
     }
 
     fn init_kernel_cmdline(&self) -> Result<(), SystemError> {
@@ -209,6 +226,16 @@ impl BootCallbacks for Mb2Callback {
         // setup kernel load base
         self.setup_kernel_load_base();
 
+        // Legacy BIOS fallback is valid only when no ACPI tag and no EFI
+        // context were supplied. UEFI systems must use their configuration
+        // table and must not probe the fixed Legacy BIOS regions.
+        if mb2_info.rsdp_v2_tag().is_none()
+            && mb2_info.rsdp_v1_tag().is_none()
+            && !has_efi_context(mb2_info)
+        {
+            cache_bios_rsdp_result();
+        }
+
         Ok(())
     }
 

kernel/src/arch/x86_64/init/pvh/mod.rs

@@ -21,6 +21,8 @@ use crate::{
 
 mod param;
 
+use super::rsdp::{cache_bios_rsdp_result, cached_bios_rsdp};
+
 static START_INFO: Lazy<HvmStartInfo> = Lazy::new();
 
 struct PvhBootCallback;
@@ -31,12 +33,29 @@ impl BootCallbacks for PvhBootCallback {
     }
 
     fn init_acpi_args(&self) -> Result<BootloaderAcpiArg, SystemError> {
-        let rsdp_paddr = PhysAddr::new(START_INFO.get().rsdp_paddr as usize);
+        let si = START_INFO.get();
+        log::info!(
+            "pvh: HvmStartInfo: magic={:#010x} version={} flags={:#x} nr_modules={} rsdp_paddr={:#x} memmap_paddr={:#x} memmap_entries={}",
+            si.magic, si.version, si.flags, si.nr_modules,
+            si.rsdp_paddr, si.memmap_paddr, si.memmap_entries
+        );
+
+        let rsdp_paddr = PhysAddr::new(si.rsdp_paddr as usize);
+
+        // if RSDP has been provided
         if rsdp_paddr.data() != 0 {
-            Ok(BootloaderAcpiArg::Rsdp(rsdp_paddr))
-        } else {
-            Ok(BootloaderAcpiArg::NotProvided)
+            return Ok(BootloaderAcpiArg::Rsdp(rsdp_paddr));
         }
+
+        // The bootloader did not provide an RSDP. Consume the shared x86
+        // early-discovery result without touching EarlyIoRemap after mm_init.
+        if let Some(paddr) = cached_bios_rsdp()? {
+            log::info!("pvh: found RSDP at {:#x}", paddr.data());
+            return Ok(BootloaderAcpiArg::Rsdp(paddr));
+        }
+
+        log::warn!("pvh: RSDP not found");
+        Ok(BootloaderAcpiArg::NotProvided)
     }
 
     fn init_kernel_cmdline(&self) -> Result<(), SystemError> {
@@ -86,7 +105,7 @@ impl BootCallbacks for PvhBootCallback {
 
                 total_mem_size += size;
                 match typ {
-                    param::E820Type::Ram => {
+                    E820Type::Ram => {
                         usable_mem_size += size;
                         mem_block_manager()
                             .add_block(start, size)
@@ -121,6 +140,16 @@ impl BootCallbacks for PvhBootCallback {
             total_mem_size,
             usable_mem_size
         );
+
+        // Discover the RSDP here, in the early boot stage: the bootstrap page
+        // table is still active and mm_init has not run yet, so EarlyIoRemap may
+        // be used safely (this mirrors Linux, which scans the RSDP in setup_arch
+        // via early_memremap). If the bootloader already provided rsdp_paddr we
+        // skip the scan. The result is cached for init_acpi_args.
+        if start_info.rsdp_paddr == 0 {
+            cache_bios_rsdp_result();
+        }
+
         Ok(())
     }
 

kernel/src/arch/x86_64/init/pvh/param.rs

@@ -160,7 +160,7 @@ pub struct HvmMemmapTableEntry {
 }
 
 /// The E820 types known to the kernel.
-#[derive(Copy, Clone, Debug)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 #[repr(u32)]
 pub enum E820Type {
     Ram = 1,