diff mbox series

[04/11] rust: add support for migration in device models

Message ID 20241024-rust-round-2-v1-4-051e7a25b978@linaro.org
State New
Headers show
Series Rust device model patches and misc cleanups | expand

Commit Message

Manos Pitsidianakis Oct. 24, 2024, 2:03 p.m. UTC
This commit adds support for declaring migration state to device models
in Rust. This is done through different but related parts:

- The Device derive macro gains new attributes `vmstate_fields` and
  `vmstate_subsections`. This allows the device declaration to include
  the vmstate fields directly at the struct definition.
- a new qemu_api module, `vmstate` was added. There a bunch of Rust
  macros declared there that are equivalent in spirit to the C macros
  declared in include/migration/vmstate.h.

  For example the Rust of equivalent of the C macro:

    VMSTATE_UINT32(field_name, struct_name)

  is:

    vmstate_uint32!(field_name, StructName)

This breathtaking development now allows us to not have to define
VMStateDescription ourselves but split the notion of migration to two
parts:

- A Migrateable trait that allows a type to define version_ids, name,
  priority, override methods like pre_load, post_load, pre_save etc.
- Define the actual vmstate fields and subsections through the Device
  derive macro right there with the struct definition:

  ------------------------ >8 ------------------------
 #[repr(C)]
 #[derive(Debug, qemu_api_macros::Object, qemu_api_macros::Device)]
+#[device(
+    class_name_override = PL011Class,
+    vmstate_fields = vmstate_fields!{
+        vmstate_unused!(u32::BITS as u64),
+        vmstate_uint32!(flags, PL011State),
+        vmstate_uint32!(line_control, PL011State),
+        vmstate_uint32!(receive_status_error_clear, PL011State),
+        vmstate_uint32!(control, PL011State),
+        vmstate_uint32!(dmacr, PL011State),
+        vmstate_uint32!(int_enabled, PL011State),
+        vmstate_uint32!(int_level, PL011State),
+        vmstate_uint32_array!(read_fifo, PL011State, PL011_FIFO_DEPTH),
+        vmstate_uint32!(ilpr, PL011State),
+        vmstate_uint32!(ibrd, PL011State),
+        vmstate_uint32!(fbrd, PL011State),
+        vmstate_uint32!(ifl, PL011State),
+        vmstate_int32!(read_pos, PL011State),
+        vmstate_int32!(read_count, PL011State),
+        vmstate_int32!(read_trigger, PL011State),
+    },
+    vmstate_subsections = vmstate_subsections!{
+        VMSTATE_PL011_CLOCK
+    }
+)]
 /// PL011 Device Model in QEMU
 pub struct PL011State {
     pub parent_obj: SysBusDevice,
  ------------------------ >8 ------------------------

Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
---
 rust/hw/char/pl011/src/device.rs    |  92 +++++++-
 rust/qemu-api-macros/src/device.rs  | 111 +++-------
 rust/qemu-api-macros/src/lib.rs     |   1 +
 rust/qemu-api-macros/src/symbols.rs |   2 +
 rust/qemu-api-macros/src/vmstate.rs | 113 ++++++++++
 rust/qemu-api/meson.build           |   1 +
 rust/qemu-api/src/lib.rs            |   3 +
 rust/qemu-api/src/vmstate.rs        | 403 ++++++++++++++++++++++++++++++++++++
 8 files changed, 637 insertions(+), 89 deletions(-)
diff mbox series

Patch

diff --git a/rust/hw/char/pl011/src/device.rs b/rust/hw/char/pl011/src/device.rs
index c469877b1ca70dd1a02e3a2449c65ad3e57c93ae..57dc37dadef631fbccfa3049a3d8701b4e62b5b3 100644
--- a/rust/hw/char/pl011/src/device.rs
+++ b/rust/hw/char/pl011/src/device.rs
@@ -10,6 +10,8 @@ 
 use qemu_api::{
     bindings::{self, *},
     objects::*,
+    vmstate_clock, vmstate_fields, vmstate_int32, vmstate_subsections, vmstate_uint32,
+    vmstate_uint32_array, vmstate_unused,
 };
 
 use crate::{
@@ -20,14 +22,74 @@ 
 
 static PL011_ID_ARM: [c_uchar; 8] = [0x11, 0x10, 0x14, 0x00, 0x0d, 0xf0, 0x05, 0xb1];
 
+/// Integer Baud Rate Divider, `UARTIBRD`
+const IBRD_MASK: u32 = 0x3f;
+
+/// Fractional Baud Rate Divider, `UARTFBRD`
+const FBRD_MASK: u32 = 0xffff;
+
 const DATA_BREAK: u32 = 1 << 10;
 
 /// QEMU sourced constant.
 pub const PL011_FIFO_DEPTH: usize = 16_usize;
 
+#[no_mangle]
+extern "C" fn pl011_clock_needed(opaque: *mut c_void) -> bool {
+    unsafe {
+        debug_assert!(!opaque.is_null());
+        let state = NonNull::new_unchecked(opaque.cast::<PL011State>());
+        state.as_ref().migrate_clock
+    }
+}
+
+qemu_api::vmstate_description! {
+    /// Migration subsection for [`PL011State`] clock.
+    pub static VMSTATE_PL011_CLOCK: VMStateDescription = VMStateDescription {
+        name: c"pl011/clock",
+        unmigratable: false,
+        early_setup: false,
+        version_id: 1,
+        minimum_version_id: 1,
+        priority: MigrationPriority::MIG_PRI_DEFAULT,
+        pre_load: None,
+        post_load: None,
+        pre_save: None,
+        post_save: None,
+        needed: Some(pl011_clock_needed),
+        dev_unplug_pending: None,
+        fields: vmstate_fields!{
+            vmstate_clock!(clock, PL011State),
+        },
+        subsections: ::core::ptr::null(),
+    };
+}
+
 #[repr(C)]
 #[derive(Debug, qemu_api_macros::Object, qemu_api_macros::Device)]
-#[device(class_name_override = PL011Class)]
+#[device(
+    class_name_override = PL011Class,
+    vmstate_fields = vmstate_fields!{
+        vmstate_unused!(u32::BITS as u64),
+        vmstate_uint32!(flags, PL011State),
+        vmstate_uint32!(line_control, PL011State),
+        vmstate_uint32!(receive_status_error_clear, PL011State),
+        vmstate_uint32!(control, PL011State),
+        vmstate_uint32!(dmacr, PL011State),
+        vmstate_uint32!(int_enabled, PL011State),
+        vmstate_uint32!(int_level, PL011State),
+        vmstate_uint32_array!(read_fifo, PL011State, PL011_FIFO_DEPTH),
+        vmstate_uint32!(ilpr, PL011State),
+        vmstate_uint32!(ibrd, PL011State),
+        vmstate_uint32!(fbrd, PL011State),
+        vmstate_uint32!(ifl, PL011State),
+        vmstate_int32!(read_pos, PL011State),
+        vmstate_int32!(read_count, PL011State),
+        vmstate_int32!(read_trigger, PL011State),
+    },
+    vmstate_subsections = vmstate_subsections!{
+        VMSTATE_PL011_CLOCK
+    }
+)]
 /// PL011 Device Model in QEMU
 pub struct PL011State {
     pub parent_obj: SysBusDevice,
@@ -165,7 +227,33 @@  fn reset(&mut self) {
     }
 }
 
-impl qemu_api::objects::Migrateable for PL011State {}
+impl qemu_api::objects::Migrateable for PL011State {
+    const NAME: Option<&'static CStr> = Some(c"pl011");
+    const UNMIGRATABLE: bool = false;
+    const VERSION_ID: c_int = 2;
+    const MINIMUM_VERSION_ID: c_int = 2;
+
+    unsafe fn post_load(&mut self, _version_id: c_int) -> c_int {
+        /* Sanity-check input state */
+        if self.read_pos >= self.read_fifo.len() || self.read_count > self.read_fifo.len() {
+            return -1;
+        }
+
+        if !self.fifo_enabled() && self.read_count > 0 && self.read_pos > 0 {
+            // Older versions of PL011 didn't ensure that the single
+            // character in the FIFO in FIFO-disabled mode is in
+            // element 0 of the array; convert to follow the current
+            // code's assumptions.
+            self.read_fifo[0] = self.read_fifo[self.read_pos];
+            self.read_pos = 0;
+        }
+
+        self.ibrd &= IBRD_MASK;
+        self.fbrd &= FBRD_MASK;
+
+        0
+    }
+}
 
 #[used]
 pub static CLK_NAME: &CStr = c"clk";
diff --git a/rust/qemu-api-macros/src/device.rs b/rust/qemu-api-macros/src/device.rs
index 3b965576a065601cd5c97d5ab6a2501f96d16a61..a666c64087715b9dc0d9ebe33f2b22d965381c64 100644
--- a/rust/qemu-api-macros/src/device.rs
+++ b/rust/qemu-api-macros/src/device.rs
@@ -10,11 +10,13 @@ 
 };
 use syn::{parse_macro_input, DeriveInput};
 
-use crate::{symbols::*, utilities::*};
+use crate::{symbols::*, utilities::*, vmstate};
 
 #[derive(Debug, Default)]
 struct DeriveContainer {
     category: Option<syn::Path>,
+    vmstate_fields: Option<syn::Expr>,
+    vmstate_subsections: Option<syn::Expr>,
     class_name: Option<syn::Ident>,
     class_name_override: Option<syn::Ident>,
 }
@@ -27,6 +29,8 @@  fn parse(input: ParseStream) -> Result<Self> {
         assert_eq!(DEVICE, bracketed.parse::<syn::Ident>()?);
         let mut retval = Self {
             category: None,
+            vmstate_fields: None,
+            vmstate_subsections: None,
             class_name: None,
             class_name_override: None,
         };
@@ -54,6 +58,20 @@  fn parse(input: ParseStream) -> Result<Self> {
                 let lit: syn::LitStr = content.parse()?;
                 let path: syn::Path = lit.parse()?;
                 retval.category = Some(path);
+            } else if value == VMSTATE_FIELDS {
+                let _: syn::Token![=] = content.parse()?;
+                if retval.vmstate_fields.is_some() {
+                    panic!("{} can only be used at most once", VMSTATE_FIELDS);
+                }
+                let expr: syn::Expr = content.parse()?;
+                retval.vmstate_fields = Some(expr);
+            } else if value == VMSTATE_SUBSECTIONS {
+                let _: syn::Token![=] = content.parse()?;
+                if retval.vmstate_subsections.is_some() {
+                    panic!("{} can only be used at most once", VMSTATE_SUBSECTIONS);
+                }
+                let expr: syn::Expr = content.parse()?;
+                retval.vmstate_subsections = Some(expr);
             } else {
                 panic!("unrecognized token `{}`", value);
             }
@@ -272,7 +290,11 @@  pub struct #class_name {
     let class_base_init_fn = format_ident!("__{}_class_base_init_generated", class_name);
 
     let (vmsd, vmsd_impl) = {
-        let (i, vmsd) = make_vmstate(name);
+        let (i, vmsd) = vmstate::make_vmstate(
+            name,
+            derive_container.vmstate_fields,
+            derive_container.vmstate_subsections,
+        );
         (quote! { &#i }, vmsd)
     };
     let category = if let Some(category) = derive_container.category {
@@ -346,88 +368,3 @@  unsafe impl ::qemu_api::objects::ClassImplUnsafe for #class_name {
         #vmsd_impl
     }
 }
-
-fn make_vmstate(name: &syn::Ident) -> (syn::Ident, proc_macro2::TokenStream) {
-    let vmstate_description_ident = format_ident!("__VMSTATE_{}", name);
-
-    let pre_load = format_ident!("__{}_pre_load_generated", name);
-    let post_load = format_ident!("__{}_post_load_generated", name);
-    let pre_save = format_ident!("__{}_pre_save_generated", name);
-    let post_save = format_ident!("__{}_post_save_generated", name);
-    let needed = format_ident!("__{}_needed_generated", name);
-    let dev_unplug_pending = format_ident!("__{}_dev_unplug_pending_generated", name);
-
-    let migrateable_fish = quote! {<#name as ::qemu_api::objects::Migrateable>};
-    let vmstate_description = quote! {
-        #[used]
-        #[allow(non_upper_case_globals)]
-        pub static #vmstate_description_ident: ::qemu_api::bindings::VMStateDescription = ::qemu_api::bindings::VMStateDescription {
-            name: if let Some(name) = #migrateable_fish::NAME {
-                name.as_ptr()
-            } else {
-                <#name as ::qemu_api::objects::ObjectImplUnsafe>::TYPE_INFO.name
-            },
-            unmigratable: #migrateable_fish::UNMIGRATABLE,
-            early_setup: #migrateable_fish::EARLY_SETUP,
-            version_id: #migrateable_fish::VERSION_ID,
-            minimum_version_id: #migrateable_fish::MINIMUM_VERSION_ID,
-            priority: #migrateable_fish::PRIORITY,
-            pre_load: Some(#pre_load),
-            post_load: Some(#post_load),
-            pre_save: Some(#pre_save),
-            post_save: Some(#post_save),
-            needed: Some(#needed),
-            dev_unplug_pending: Some(#dev_unplug_pending),
-            fields: ::core::ptr::null(),
-            subsections: ::core::ptr::null(),
-        };
-
-        #[no_mangle]
-        pub unsafe extern "C" fn #pre_load(opaque: *mut ::core::ffi::c_void) -> ::core::ffi::c_int {
-            let mut instance = NonNull::new(opaque.cast::<#name>()).expect(concat!("Expected opaque to be a non-null pointer of type ", stringify!(#name), "::Object"));
-            unsafe {
-                ::qemu_api::objects::Migrateable::pre_load(instance.as_mut())
-            }
-        }
-        #[no_mangle]
-        pub unsafe extern "C" fn #post_load(opaque: *mut ::core::ffi::c_void, version_id: core::ffi::c_int) -> ::core::ffi::c_int {
-            let mut instance = NonNull::new(opaque.cast::<#name>()).expect(concat!("Expected opaque to be a non-null pointer of type ", stringify!(#name), "::Object"));
-            unsafe {
-                ::qemu_api::objects::Migrateable::post_load(instance.as_mut(), version_id)
-            }
-        }
-        #[no_mangle]
-        pub unsafe extern "C" fn #pre_save(opaque: *mut ::core::ffi::c_void) -> ::core::ffi::c_int {
-            let mut instance = NonNull::new(opaque.cast::<#name>()).expect(concat!("Expected opaque to be a non-null pointer of type ", stringify!(#name), "::Object"));
-            unsafe {
-                ::qemu_api::objects::Migrateable::pre_save(instance.as_mut())
-            }
-        }
-        #[no_mangle]
-        pub unsafe extern "C" fn #post_save(opaque: *mut ::core::ffi::c_void) -> ::core::ffi::c_int {
-            let mut instance = NonNull::new(opaque.cast::<#name>()).expect(concat!("Expected opaque to be a non-null pointer of type ", stringify!(#name), "::Object"));
-            unsafe {
-                ::qemu_api::objects::Migrateable::post_save(instance.as_mut())
-            }
-        }
-        #[no_mangle]
-        pub unsafe extern "C" fn #needed(opaque: *mut ::core::ffi::c_void) -> bool {
-            let mut instance = NonNull::new(opaque.cast::<#name>()).expect(concat!("Expected opaque to be a non-null pointer of type ", stringify!(#name), "::Object"));
-            unsafe {
-                ::qemu_api::objects::Migrateable::needed(instance.as_mut())
-            }
-        }
-        #[no_mangle]
-        pub unsafe extern "C" fn #dev_unplug_pending(opaque: *mut ::core::ffi::c_void) -> bool {
-            let mut instance = NonNull::new(opaque.cast::<#name>()).expect(concat!("Expected opaque to be a non-null pointer of type ", stringify!(#name), "::Object"));
-            unsafe {
-                ::qemu_api::objects::Migrateable::dev_unplug_pending(instance.as_mut())
-            }
-        }
-    };
-
-    let expanded = quote! {
-        #vmstate_description
-    };
-    (vmstate_description_ident, expanded)
-}
diff --git a/rust/qemu-api-macros/src/lib.rs b/rust/qemu-api-macros/src/lib.rs
index 7753a853fae72fc87e6dc642cf076c6d0c736345..7b5c0c044da879241b05bba75edcb17b498e5d5a 100644
--- a/rust/qemu-api-macros/src/lib.rs
+++ b/rust/qemu-api-macros/src/lib.rs
@@ -10,6 +10,7 @@ 
 mod object;
 mod symbols;
 mod utilities;
+mod vmstate;
 
 #[proc_macro_derive(Object)]
 pub fn derive_object(input: TokenStream) -> TokenStream {
diff --git a/rust/qemu-api-macros/src/symbols.rs b/rust/qemu-api-macros/src/symbols.rs
index f73768d228ed2b4d478c18336db56cb11e70f012..79c242cf069d5de1dd0cd61b2a5c7814564af47e 100644
--- a/rust/qemu-api-macros/src/symbols.rs
+++ b/rust/qemu-api-macros/src/symbols.rs
@@ -15,6 +15,8 @@ 
 pub const CLASS_NAME_OVERRIDE: Symbol = Symbol("class_name_override");
 pub const QDEV_PROP: Symbol = Symbol("qdev_prop");
 pub const MIGRATEABLE: Symbol = Symbol("migrateable");
+pub const VMSTATE_FIELDS: Symbol = Symbol("vmstate_fields");
+pub const VMSTATE_SUBSECTIONS: Symbol = Symbol("vmstate_subsections");
 pub const PROPERTIES: Symbol = Symbol("properties");
 pub const PROPERTY: Symbol = Symbol("property");
 
diff --git a/rust/qemu-api-macros/src/vmstate.rs b/rust/qemu-api-macros/src/vmstate.rs
new file mode 100644
index 0000000000000000000000000000000000000000..2d72bf13b5acc861fac0814d749762ddb76824d5
--- /dev/null
+++ b/rust/qemu-api-macros/src/vmstate.rs
@@ -0,0 +1,113 @@ 
+// Copyright 2024, Linaro Limited
+// Author(s): Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+use quote::{format_ident, quote};
+
+pub fn make_vmstate(
+    name: &syn::Ident,
+    vmstate_fields: Option<syn::Expr>,
+    vmstate_subsections: Option<syn::Expr>,
+) -> (syn::Ident, proc_macro2::TokenStream) {
+    let vmstate_description_ident = format_ident!("__VMSTATE_{}", name);
+
+    let pre_load = format_ident!("__{}_pre_load_generated", name);
+    let post_load = format_ident!("__{}_post_load_generated", name);
+    let pre_save = format_ident!("__{}_pre_save_generated", name);
+    let post_save = format_ident!("__{}_post_save_generated", name);
+    let needed = format_ident!("__{}_needed_generated", name);
+    let dev_unplug_pending = format_ident!("__{}_dev_unplug_pending_generated", name);
+
+    let migrateable_fish = quote! {<#name as ::qemu_api::objects::Migrateable>};
+    let vmstate_fields = if let Some(fields) = vmstate_fields {
+        quote! {
+            #fields
+        }
+    } else {
+        quote! {
+            ::core::ptr::null()
+        }
+    };
+    let vmstate_subsections = if let Some(subsections) = vmstate_subsections {
+        quote! {
+            #subsections
+        }
+    } else {
+        quote! {
+            ::core::ptr::null()
+        }
+    };
+
+    let vmstate_description = quote! {
+        #[used]
+        #[allow(non_upper_case_globals)]
+        pub static #vmstate_description_ident: ::qemu_api::bindings::VMStateDescription = ::qemu_api::bindings::VMStateDescription {
+            name: if let Some(name) = #migrateable_fish::NAME {
+                name.as_ptr()
+            } else {
+                <#name as ::qemu_api::objects::ObjectImplUnsafe>::TYPE_INFO.name
+            },
+            unmigratable: #migrateable_fish::UNMIGRATABLE,
+            early_setup: #migrateable_fish::EARLY_SETUP,
+            version_id: #migrateable_fish::VERSION_ID,
+            minimum_version_id: #migrateable_fish::MINIMUM_VERSION_ID,
+            priority: #migrateable_fish::PRIORITY,
+            pre_load: Some(#pre_load),
+            post_load: Some(#post_load),
+            pre_save: Some(#pre_save),
+            post_save: Some(#post_save),
+            needed: Some(#needed),
+            dev_unplug_pending: Some(#dev_unplug_pending),
+            fields: #vmstate_fields,
+            subsections: #vmstate_subsections,
+        };
+
+        #[no_mangle]
+        pub unsafe extern "C" fn #pre_load(opaque: *mut ::core::ffi::c_void) -> ::core::ffi::c_int {
+            let mut instance = NonNull::new(opaque.cast::<#name>()).expect(concat!("Expected opaque to be a non-null pointer of type ", stringify!(#name), "::Object"));
+            unsafe {
+                ::qemu_api::objects::Migrateable::pre_load(instance.as_mut())
+            }
+        }
+        #[no_mangle]
+        pub unsafe extern "C" fn #post_load(opaque: *mut ::core::ffi::c_void, version_id: core::ffi::c_int) -> ::core::ffi::c_int {
+            let mut instance = NonNull::new(opaque.cast::<#name>()).expect(concat!("Expected opaque to be a non-null pointer of type ", stringify!(#name), "::Object"));
+            unsafe {
+                ::qemu_api::objects::Migrateable::post_load(instance.as_mut(), version_id)
+            }
+        }
+        #[no_mangle]
+        pub unsafe extern "C" fn #pre_save(opaque: *mut ::core::ffi::c_void) -> ::core::ffi::c_int {
+            let mut instance = NonNull::new(opaque.cast::<#name>()).expect(concat!("Expected opaque to be a non-null pointer of type ", stringify!(#name), "::Object"));
+            unsafe {
+                ::qemu_api::objects::Migrateable::pre_save(instance.as_mut())
+            }
+        }
+        #[no_mangle]
+        pub unsafe extern "C" fn #post_save(opaque: *mut ::core::ffi::c_void) -> ::core::ffi::c_int {
+            let mut instance = NonNull::new(opaque.cast::<#name>()).expect(concat!("Expected opaque to be a non-null pointer of type ", stringify!(#name), "::Object"));
+            unsafe {
+                ::qemu_api::objects::Migrateable::post_save(instance.as_mut())
+            }
+        }
+        #[no_mangle]
+        pub unsafe extern "C" fn #needed(opaque: *mut ::core::ffi::c_void) -> bool {
+            let mut instance = NonNull::new(opaque.cast::<#name>()).expect(concat!("Expected opaque to be a non-null pointer of type ", stringify!(#name), "::Object"));
+            unsafe {
+                ::qemu_api::objects::Migrateable::needed(instance.as_mut())
+            }
+        }
+        #[no_mangle]
+        pub unsafe extern "C" fn #dev_unplug_pending(opaque: *mut ::core::ffi::c_void) -> bool {
+            let mut instance = NonNull::new(opaque.cast::<#name>()).expect(concat!("Expected opaque to be a non-null pointer of type ", stringify!(#name), "::Object"));
+            unsafe {
+                ::qemu_api::objects::Migrateable::dev_unplug_pending(instance.as_mut())
+            }
+        }
+    };
+
+    let expanded = quote! {
+        #vmstate_description
+    };
+    (vmstate_description_ident, expanded)
+}
diff --git a/rust/qemu-api/meson.build b/rust/qemu-api/meson.build
index 0bd70b59afcc005251135802897954789b068e6e..11984abb878bef18be3c819f61da24ce1405ea59 100644
--- a/rust/qemu-api/meson.build
+++ b/rust/qemu-api/meson.build
@@ -4,6 +4,7 @@  _qemu_api_rs = static_library(
     [
       'src/lib.rs',
       'src/objects.rs',
+      'src/vmstate.rs',
     ],
     {'.' : bindings_rs},
   ),
diff --git a/rust/qemu-api/src/lib.rs b/rust/qemu-api/src/lib.rs
index b94adc15288cdc62de7679988f549ebd80f895d7..d276adfb6622eee6e42494e089e1f20b0b5cdf08 100644
--- a/rust/qemu-api/src/lib.rs
+++ b/rust/qemu-api/src/lib.rs
@@ -26,8 +26,11 @@  unsafe impl Send for bindings::Property {}
 unsafe impl Sync for bindings::Property {}
 unsafe impl Sync for bindings::TypeInfo {}
 unsafe impl Sync for bindings::VMStateDescription {}
+unsafe impl Sync for bindings::VMStateField {}
+unsafe impl Sync for bindings::VMStateInfo {}
 
 pub mod objects;
+pub mod vmstate;
 
 use std::alloc::{GlobalAlloc, Layout};
 
diff --git a/rust/qemu-api/src/vmstate.rs b/rust/qemu-api/src/vmstate.rs
new file mode 100644
index 0000000000000000000000000000000000000000..4478febc9ac2768cca3e638ebae27b042edb1bf2
--- /dev/null
+++ b/rust/qemu-api/src/vmstate.rs
@@ -0,0 +1,403 @@ 
+// Copyright 2024, Linaro Limited
+// Author(s): Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Helper macros to declare migration state for device models.
+//!
+//! Some macros are direct equivalents to the C macros declared in `include/migration/vmstate.h`
+//! while [`vmstate_description`], [`vmstate_subsections`] and [`vmstate_fields`] are meant to be
+//! used when declaring a device model state struct with the [`Device`](qemu_api_macros::Device)
+//! `Derive` macro.
+
+#[doc(alias = "VMSTATE_UNUSED_BUFFER")]
+#[macro_export]
+macro_rules! vmstate_unused_buffer {
+    ($field_exists_fn:expr, $version_id:expr, $size:expr) => {{
+        $crate::bindings::VMStateField {
+            name: c"unused".as_ptr(),
+            err_hint: ::core::ptr::null(),
+            offset: 0,
+            size: $size,
+            start: 0,
+            num: 0,
+            num_offset: 0,
+            size_offset: 0,
+            info: unsafe { ::core::ptr::addr_of!($crate::bindings::vmstate_info_unused_buffer) },
+            flags: VMStateFlags::VMS_BUFFER,
+            vmsd: ::core::ptr::null(),
+            version_id: $version_id,
+            struct_version_id: 0,
+            field_exists: $field_exists_fn,
+        }
+    }};
+}
+
+#[doc(alias = "VMSTATE_UNUSED_V")]
+#[macro_export]
+macro_rules! vmstate_unused_v {
+    ($version_id:expr, $size:expr) => {{
+        $crate::vmstate_unused_buffer!(None, $version_id, $size)
+    }};
+}
+
+#[doc(alias = "VMSTATE_UNUSED")]
+#[macro_export]
+macro_rules! vmstate_unused {
+    ($size:expr) => {{
+        $crate::vmstate_unused_v!(0, $size)
+    }};
+}
+
+#[doc(alias = "VMSTATE_SINGLE_TEST")]
+#[macro_export]
+macro_rules! vmstate_single_test {
+    ($field_name:ident, $struct_name:ty, $field_exists_fn:expr, $version_id:expr, $info:block, $size:expr) => {{
+        $crate::bindings::VMStateField {
+            name: ::core::concat!(::core::stringify!($field_name), 0)
+                .as_bytes()
+                .as_ptr() as *const ::core::ffi::c_char,
+            err_hint: ::core::ptr::null(),
+            offset: ::core::mem::offset_of!($struct_name, $field_name) as _,
+            size: $size,
+            start: 0,
+            num: 0,
+            num_offset: 0,
+            size_offset: 0,
+            info: $info,
+            flags: VMStateFlags::VMS_SINGLE,
+            vmsd: ::core::ptr::null(),
+            version_id: $version_id,
+            struct_version_id: 0,
+            field_exists: $field_exists_fn,
+        }
+    }};
+}
+
+#[doc(alias = "VMSTATE_SINGLE")]
+#[macro_export]
+macro_rules! vmstate_single {
+    ($field_name:ident, $struct_name:ty, $version_id:expr, $info:block, $size:expr) => {{
+        $crate::vmstate_single_test!($field_name, $struct_name, None, $version_id, $info, $size)
+    }};
+}
+
+#[doc(alias = "VMSTATE_UINT32_V")]
+#[macro_export]
+macro_rules! vmstate_uint32_v {
+    ($field_name:ident, $struct_name:ty, $version_id:expr) => {{
+        $crate::vmstate_single!(
+            $field_name,
+            $struct_name,
+            $version_id,
+            { unsafe { ::core::ptr::addr_of!($crate::bindings::vmstate_info_uint32) } },
+            u32::BITS as u64
+        )
+    }};
+}
+
+#[doc(alias = "VMSTATE_UINT32")]
+#[macro_export]
+macro_rules! vmstate_uint32 {
+    ($field_name:ident, $struct_name:ty) => {{
+        $crate::vmstate_uint32_v!($field_name, $struct_name, 0)
+    }};
+}
+
+#[doc(alias = "VMSTATE_INT32_V")]
+#[macro_export]
+macro_rules! vmstate_int32_v {
+    ($field_name:ident, $struct_name:ty, $version_id:expr) => {{
+        $crate::vmstate_single!(
+            $field_name,
+            $struct_name,
+            $version_id,
+            { unsafe { ::core::ptr::addr_of!($crate::bindings::vmstate_info_int32) } },
+            i32::BITS as u64
+        )
+    }};
+}
+
+#[doc(alias = "VMSTATE_INT32")]
+#[macro_export]
+macro_rules! vmstate_int32 {
+    ($field_name:ident, $struct_name:ty) => {{
+        $crate::vmstate_int32_v!($field_name, $struct_name, 0)
+    }};
+}
+
+#[doc(alias = "VMSTATE_ARRAY")]
+#[macro_export]
+macro_rules! vmstate_array {
+    ($field_name:ident, $struct_name:ty, $length:expr, $version_id:expr, $info:block, $size:expr) => {{
+        $crate::bindings::VMStateField {
+            name: ::core::concat!(::core::stringify!($field_name), 0)
+                .as_bytes()
+                .as_ptr() as *const ::core::ffi::c_char,
+            err_hint: ::core::ptr::null(),
+            offset: ::core::mem::offset_of!($struct_name, $field_name) as _,
+            size: $size,
+            start: 0,
+            num: $length as _,
+            num_offset: 0,
+            size_offset: 0,
+            info: $info,
+            flags: VMStateFlags::VMS_ARRAY,
+            vmsd: ::core::ptr::null(),
+            version_id: $version_id,
+            struct_version_id: 0,
+            field_exists: None,
+        }
+    }};
+}
+
+#[doc(alias = "VMSTATE_UINT32_ARRAY_V")]
+#[macro_export]
+macro_rules! vmstate_uint32_array_v {
+    ($field_name:ident, $struct_name:ty, $length:expr, $version_id:expr) => {{
+        $crate::vmstate_array!(
+            $field_name,
+            $struct_name,
+            $length,
+            $version_id,
+            { unsafe { ::core::ptr::addr_of!($crate::bindings::vmstate_info_uint32) } },
+            u32::BITS as u64
+        )
+    }};
+}
+
+#[doc(alias = "VMSTATE_UINT32_ARRAY")]
+#[macro_export]
+macro_rules! vmstate_uint32_array {
+    ($field_name:ident, $struct_name:ty, $length:expr) => {{
+        $crate::vmstate_uint32_array_v!($field_name, $struct_name, $length, 0)
+    }};
+}
+
+#[doc(alias = "VMSTATE_STRUCT_POINTER_V")]
+#[macro_export]
+macro_rules! vmstate_struct_pointer_v {
+    ($field_name:ident, $struct_name:ty, $version_id:expr, $vmsd:expr, $type:ty) => {{
+        $crate::bindings::VMStateField {
+            name: ::core::concat!(::core::stringify!($field_name), 0)
+                .as_bytes()
+                .as_ptr() as *const ::core::ffi::c_char,
+            err_hint: ::core::ptr::null(),
+            offset: ::core::mem::offset_of!($struct_name, $field_name) as _,
+            size: ::core::mem::size_of::<*const $type>() as _,
+            start: 0,
+            num: 0,
+            num_offset: 0,
+            size_offset: 0,
+            info: ::core::ptr::null(),
+            flags: VMStateFlags(VMStateFlags::VMS_STRUCT.0 | VMStateFlags::VMS_POINTER.0),
+            vmsd: $vmsd,
+            version_id: $version_id,
+            struct_version_id: 0,
+            field_exists: None,
+        }
+    }};
+}
+
+#[doc(alias = "VMSTATE_ARRAY_OF_POINTER")]
+#[macro_export]
+macro_rules! vmstate_array_of_pointer {
+    ($field_name:ident, $struct_name:ty, $num:expr, $version_id:expr, $info:expr, $type:ty) => {{
+        $crate::bindings::VMStateField {
+            name: ::core::concat!(::core::stringify!($field_name), 0)
+                .as_bytes()
+                .as_ptr() as *const ::core::ffi::c_char,
+            version_id: $version_id,
+            num: $num,
+            info: $info,
+            size: ::core::mem::size_of::<*const $type>() as _,
+            flags: VMStateFlags(VMStateFlags::VMS_ARRAY.0 | VMStateFlags::VMS_ARRAY_OF_POINTER.0),
+            offset: ::core::mem::offset_of!($struct_name, $field_name) as _,
+            err_hint: ::core::ptr::null(),
+            start: 0,
+            num_offset: 0,
+            size_offset: 0,
+            vmsd: ::core::ptr::null(),
+            struct_version_id: 0,
+            field_exists: None,
+        }
+    }};
+}
+
+#[doc(alias = "VMSTATE_ARRAY_OF_POINTER_TO_STRUCT")]
+#[macro_export]
+macro_rules! vmstate_array_of_pointer_to_struct {
+    ($field_name:ident, $struct_name:ty, $num:expr, $version_id:expr, $vmsd:expr, $type:ty) => {{
+        $crate::bindings::VMStateField {
+            name: ::core::concat!(::core::stringify!($field_name), 0)
+                .as_bytes()
+                .as_ptr() as *const ::core::ffi::c_char,
+            version_id: $version_id,
+            num: $num,
+            vmsd: $vmsd,
+            size: ::core::mem::size_of::<*const $type>() as _,
+            flags: VMStateFlags(
+                VMStateFlags::VMS_ARRAY.0
+                    | VMStateFlags::VMS_STRUCT.0
+                    | VMStateFlags::VMS_ARRAY_OF_POINTER.0,
+            ),
+            offset: ::core::mem::offset_of!($struct_name, $field_name) as _,
+            err_hint: ::core::ptr::null(),
+            start: 0,
+            num_offset: 0,
+            size_offset: 0,
+            vmsd: ::core::ptr::null(),
+            struct_version_id: 0,
+            field_exists: None,
+        }
+    }};
+}
+
+#[doc(alias = "VMSTATE_CLOCK_V")]
+#[macro_export]
+macro_rules! vmstate_clock_v {
+    ($field_name:ident, $struct_name:ty, $version_id:expr) => {{
+        $crate::vmstate_struct_pointer_v!(
+            $field_name,
+            $struct_name,
+            $version_id,
+            { unsafe { ::core::ptr::addr_of!($crate::bindings::vmstate_clock) } },
+            $crate::bindings::Clock
+        )
+    }};
+}
+
+#[doc(alias = "VMSTATE_CLOCK")]
+#[macro_export]
+macro_rules! vmstate_clock {
+    ($field_name:ident, $struct_name:ty) => {{
+        $crate::vmstate_clock_v!($field_name, $struct_name, 0)
+    }};
+}
+
+#[doc(alias = "VMSTATE_ARRAY_CLOCK_V")]
+#[macro_export]
+macro_rules! vmstate_array_clock_v {
+    ($field_name:ident, $struct_name:ty, $num:expr, $version_id:expr) => {{
+        $crate::vmstate_array_of_pointer_to_struct!(
+            $field_name,
+            $struct_name,
+            $num,
+            $version_id,
+            { unsafe { ::core::ptr::addr_of!($crate::bindings::vmstate_clock) } },
+            $crate::bindings::Clock
+        )
+    }};
+}
+
+#[doc(alias = "VMSTATE_ARRAY_CLOCK")]
+#[macro_export]
+macro_rules! vmstate_array_clock {
+    ($field_name:ident, $struct_name:ty, $num:expr) => {{
+        $crate::vmstate_array_clock_v!($field_name, $struct_name, $name, 0)
+    }};
+}
+
+/// Helper macro to declare a list of
+/// ([`VMStateField`](`crate::bindings::VMStateField`)) into a static and return a
+/// pointer to the array of values it created.
+#[macro_export]
+macro_rules! vmstate_fields {
+    ($($field:expr),*$(,)*) => {{
+        #[used]
+        static _FIELDS: &[$crate::bindings::VMStateField] = &[
+            $($field),*,
+            $crate::bindings::VMStateField {
+                name: ::core::ptr::null(),
+                err_hint: ::core::ptr::null(),
+                offset: 0,
+                size: 0,
+                start: 0,
+                num: 0,
+                num_offset: 0,
+                size_offset: 0,
+                info: ::core::ptr::null(),
+                flags: VMStateFlags::VMS_END,
+                vmsd: ::core::ptr::null(),
+                version_id: 0,
+                struct_version_id: 0,
+                field_exists: None,
+            }
+        ];
+        _FIELDS.as_ptr()
+    }}
+}
+
+/// A transparent wrapper type for the `subsections` field of
+/// [`VMStateDescription`](crate::bindings::VMStateDescription).
+///
+/// This is necessary to be able to declare subsection descriptions as statics, because the only
+/// way to implement `Sync` for a foreign type (and `*const` pointers are foreign types in Rust) is
+/// to create a wrapper struct and `unsafe impl Sync` for it.
+///
+/// This struct is used in the [`vmstate_subsections`] macro implementation.
+#[repr(transparent)]
+pub struct VMStateSubsectionsWrapper(pub &'static [*const crate::bindings::VMStateDescription]);
+
+unsafe impl Sync for VMStateSubsectionsWrapper {}
+
+/// Helper macro to declare a list of subsections
+/// ([`VMStateDescription`](`crate::bindings::VMStateDescription`)) into a static and return a
+/// pointer to the array of pointers it created.
+#[macro_export]
+macro_rules! vmstate_subsections {
+    ($($subsection:expr),*$(,)*) => {{
+        #[used]
+        static _SUBSECTIONS: $crate::vmstate::VMStateSubsectionsWrapper = $crate::vmstate::VMStateSubsectionsWrapper(&[
+            $({
+                #[used]
+                static _SUBSECTION: $crate::bindings::VMStateDescription = $subsection;
+                ::core::ptr::addr_of!(_SUBSECTION)
+            }),*,
+            ::core::ptr::null()
+        ]);
+        _SUBSECTIONS.0.as_ptr()
+    }}
+}
+
+/// Thin macro to declare a valid [`VMStateDescription`](`crate::bindings::VMStateDescription`)
+/// static.
+#[macro_export]
+macro_rules! vmstate_description {
+    ($(#[$outer:meta])*
+     pub static $name:ident: VMStateDescription = VMStateDescription {
+         name: $vname:expr,
+         unmigratable: $um_val:expr,
+         early_setup: $early_setup:expr,
+         version_id: $version_id:expr,
+         minimum_version_id: $minimum_version_id:expr,
+         priority: $priority:expr,
+         pre_load: $pre_load_fn:expr,
+         post_load: $post_load_fn:expr,
+         pre_save: $pre_save_fn:expr,
+         post_save: $post_save_fn:expr,
+         needed: $needed_fn:expr,
+         dev_unplug_pending: $dev_unplug_pending_fn:expr,
+         fields: $fields:expr,
+         subsections: $subsections:expr$(,)*
+     };
+    ) => {
+        #[used]
+        $(#[$outer])*
+            pub static $name: $crate::bindings::VMStateDescription = $crate::bindings::VMStateDescription {
+                name: ::core::ffi::CStr::as_ptr($vname),
+                unmigratable: $um_val,
+                early_setup: $early_setup,
+                version_id: $version_id,
+                minimum_version_id: $minimum_version_id,
+                priority: $priority,
+                pre_load: None,
+                post_load: None,
+                pre_save: None,
+                post_save: None,
+                needed: None,
+                dev_unplug_pending: None,
+                fields: $fields,
+                subsections: $subsections,
+            };
+    }
+}