rust: pl011: fix migration stream

The Rust vmstate macros lack the type-safety of their C equivalents (so
safe, much abstraction), and therefore they were predictably wrong.

The registers have already been changed to 32-bits in the previous patch,
but read_pos/read_count/read_trigger also have to be u32 instead of usize.
The easiest way to do so is to let the FIFO use u32 indices instead
of usize.

My plan for making VMStateField typesafe is to have a trait to retrieve
a basic VMStateField; for example something like vmstate_uint32 would
become an implementation of the VMState trait on u32.  Then you'd write
something like "vmstate_of!(Type, field).with_version_id(2)".  That is,
vmstate_of retrieves the basic VMStateField and fills in the offset,
and then more changes can be applied on top.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/rust/hw/char/pl011/src/device.rs b/rust/hw/char/pl011/src/device.rs
index 090e5d6450481b20a3081218578adcf2b2896cd8..4d620b442edd68f13601c6a67dde1d11c0f0373d 100644 (file)
--- a/rust/hw/char/pl011/src/device.rs
+++ b/rust/hw/char/pl011/src/device.rs
@@ -31,7 +31,7 @@ const IBRD_MASK: u32 = 0xffff;
 const FBRD_MASK: u32 = 0x3f;
 
 /// QEMU sourced constant.
-pub const PL011_FIFO_DEPTH: usize = 16_usize;
+pub const PL011_FIFO_DEPTH: u32 = 16;
 
 #[derive(Clone, Copy, Debug)]
 enum DeviceId {
@@ -56,6 +56,32 @@ impl DeviceId {
     const PL011_ID_LUMINARY: [c_uchar; 8] = [0x11, 0x00, 0x18, 0x01, 0x0d, 0xf0, 0x05, 0xb1];
 }
 
+// FIFOs use 32-bit indices instead of usize, for compatibility with
+// the migration stream produced by the C version of this device.
+#[repr(transparent)]
+#[derive(Debug, Default)]
+pub struct Fifo([registers::Data; PL011_FIFO_DEPTH as usize]);
+
+impl Fifo {
+    const fn len(&self) -> u32 {
+        self.0.len() as u32
+    }
+}
+
+impl std::ops::IndexMut<u32> for Fifo {
+    fn index_mut(&mut self, idx: u32) -> &mut Self::Output {
+        &mut self.0[idx as usize]
+    }
+}
+
+impl std::ops::Index<u32> for Fifo {
+    type Output = registers::Data;
+
+    fn index(&self, idx: u32) -> &Self::Output {
+        &self.0[idx as usize]
+    }
+}
+
 #[repr(C)]
 #[derive(Debug, qemu_api_macros::Object, qemu_api_macros::offsets)]
 /// PL011 Device Model in QEMU
@@ -73,14 +99,14 @@ pub struct PL011State {
     pub dmacr: u32,
     pub int_enabled: u32,
     pub int_level: u32,
-    pub read_fifo: [registers::Data; PL011_FIFO_DEPTH],
+    pub read_fifo: Fifo,
     pub ilpr: u32,
     pub ibrd: u32,
     pub fbrd: u32,
     pub ifl: u32,
-    pub read_pos: usize,
-    pub read_count: usize,
-    pub read_trigger: usize,
+    pub read_pos: u32,
+    pub read_count: u32,
+    pub read_trigger: u32,
     #[doc(alias = "chr")]
     pub char_backend: CharBackend,
     /// QEMU interrupts
@@ -480,7 +506,7 @@ impl PL011State {
     }
 
     #[inline]
-    pub fn fifo_depth(&self) -> usize {
+    pub fn fifo_depth(&self) -> u32 {
         // Note: FIFO depth is expected to be power-of-2
         if self.fifo_enabled() {
             return PL011_FIFO_DEPTH;

diff --git a/rust/hw/char/pl011/src/device_class.rs b/rust/hw/char/pl011/src/device_class.rs
index 975c3d42be7db4d6cc549929611055a9a86e75bd..7f3ca8950716986f62c386172baa13de0efcca7a 100644 (file)
--- a/rust/hw/char/pl011/src/device_class.rs
+++ b/rust/hw/char/pl011/src/device_class.rs
@@ -6,8 +6,8 @@ use core::ptr::NonNull;
 use std::os::raw::{c_int, c_void};
 
 use qemu_api::{
-    bindings::*, c_str, vmstate_clock, vmstate_fields, vmstate_int32, vmstate_subsections,
-    vmstate_uint32, vmstate_uint32_array, vmstate_unused, zeroable::Zeroable,
+    bindings::*, c_str, vmstate_clock, vmstate_fields, vmstate_subsections, vmstate_uint32,
+    vmstate_uint32_array, vmstate_unused, zeroable::Zeroable,
 };
 
 use crate::device::{PL011State, PL011_FIFO_DEPTH};
@@ -64,9 +64,9 @@ pub static VMSTATE_PL011: VMStateDescription = VMStateDescription {
         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_uint32!(read_pos, PL011State),
+        vmstate_uint32!(read_count, PL011State),
+        vmstate_uint32!(read_trigger, PL011State),
     },
     subsections: vmstate_subsections! {
         VMSTATE_PL011_CLOCK

diff --git a/rust/qemu-api/src/vmstate.rs b/rust/qemu-api/src/vmstate.rs
index 25c68b703eab9c36d8373e702300b56fc08f5009..63c897abcdffae62cbc0d6978329ac923b498911 100644 (file)
--- a/rust/qemu-api/src/vmstate.rs
+++ b/rust/qemu-api/src/vmstate.rs
@@ -106,28 +106,6 @@ macro_rules! vmstate_uint32 {
     }};
 }
 
-#[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,
-            $version_id,
-            ::core::ptr::addr_of!($crate::bindings::vmstate_info_int32),
-            ::core::mem::size_of::<i32>()
-        )
-    }};
-}
-
-#[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 {