rust: add bindings for interrupt sources

The InterruptSource bindings let us call qemu_set_irq() and sysbus_init_irq()
as safe code.

Interrupt sources, qemu_irq in C code, are pointers to IRQState objects.
They are QOM link properties and can be written to outside the control
of the device (i.e. from a shared reference); therefore they must be
interior-mutable in Rust.  Since thread-safety is provided by the BQL,
what we want here is the newly-introduced BqlCell.  A pointer to the
contents of the BqlCell (an IRQState**, or equivalently qemu_irq*)
is then passed to the C sysbus_init_irq function.

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

1 files changed, 12 insertions, 10 deletions

diff --git a/rust/hw/char/pl011/src/device.rs b/rust/hw/char/pl011/src/device.rs
index 317a9b3c5a..c5c8c463d3 100644
--- a/rust/hw/char/pl011/src/device.rs
+++ b/rust/hw/char/pl011/src/device.rs
@@ -13,6 +13,7 @@ use qemu_api::{
     c_str,
     definitions::ObjectImpl,
     device_class::TYPE_SYS_BUS_DEVICE,
+    irq::InterruptSource,
 };
 
 use crate::{
@@ -94,7 +95,7 @@ pub struct PL011State {
     ///  * sysbus IRQ 5: `UARTEINTR` (error interrupt line)
     /// ```
     #[doc(alias = "irq")]
-    pub interrupts: [qemu_irq; 6usize],
+    pub interrupts: [InterruptSource; IRQMASK.len()],
     #[doc(alias = "clk")]
     pub clock: NonNull<Clock>,
     #[doc(alias = "migrate_clk")]
@@ -139,7 +140,8 @@ impl PL011State {
     unsafe fn init(&mut self) {
         const CLK_NAME: &CStr = c_str!("clk");
 
-        let dev = addr_of_mut!(*self).cast::<DeviceState>();
+        let sbd = unsafe { &mut *(addr_of_mut!(*self).cast::<SysBusDevice>()) };
+
         // SAFETY:
         //
         // self and self.iomem are guaranteed to be valid at this point since callers
@@ -153,12 +155,15 @@ impl PL011State {
                 Self::TYPE_INFO.name,
                 0x1000,
             );
-            let sbd = addr_of_mut!(*self).cast::<SysBusDevice>();
             sysbus_init_mmio(sbd, addr_of_mut!(self.iomem));
-            for irq in self.interrupts.iter_mut() {
-                sysbus_init_irq(sbd, irq);
-            }
         }
+
+        for irq in self.interrupts.iter() {
+            sbd.init_irq(irq);
+        }
+
+        let dev = addr_of_mut!(*self).cast::<DeviceState>();
+
         // SAFETY:
         //
         // self.clock is not initialized at this point; but since `NonNull<_>` is Copy,
@@ -498,10 +503,7 @@ impl PL011State {
     pub fn update(&self) {
         let flags = self.int_level & self.int_enabled;
         for (irq, i) in self.interrupts.iter().zip(IRQMASK) {
-            // SAFETY: self.interrupts have been initialized in init().
-            unsafe {
-                qemu_set_irq(*irq, i32::from(flags & i != 0));
-            }
+            irq.set(flags & i != 0);
         }
     }