From e33e05787511572beced7077cc5b891943eb0b54 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= <marcandre.lureau@redhat.com>
Date: Tue, 14 Jan 2025 18:33:43 +0400
Subject: [PATCH] qemu-display: add back manual win32 mmap
MIME-Version: 1.0
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It's not yet possible to map from a mapping object in memmap2...

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 qemu-display/src/audio.rs            | 19 +++++-----
 qemu-display/src/console.rs          |  4 +--
 qemu-display/src/console_listener.rs | 11 +++++-
 qemu-display/src/win32.rs            | 52 +++++++++++++++++++++++++++-
 qemu-rdw/src/display.rs              |  2 --
 5 files changed, 70 insertions(+), 18 deletions(-)

diff --git a/qemu-display/src/audio.rs b/qemu-display/src/audio.rs
index d6bb221..65cb1e9 100644
--- a/qemu-display/src/audio.rs
+++ b/qemu-display/src/audio.rs
@@ -269,11 +269,10 @@ impl Audio {
             &p0,
         )?;
         self.proxy.register_out_listener(p0).await?;
-        let conn = zbus::connection::Builder::unix_stream(p1).p2p()
-            .serve_at(
-                "/org/qemu/Display1/AudioOutListener",
-                AudioOutListener { handler },
-            )?;
+        let conn = zbus::connection::Builder::unix_stream(p1).p2p().serve_at(
+            "/org/qemu/Display1/AudioOutListener",
+            AudioOutListener { handler },
+        )?;
         #[cfg(windows)]
         let conn = conn.auth_mechanism(zbus::AuthMechanism::Anonymous);
         let conn = conn.build().await?;
@@ -289,12 +288,10 @@ impl Audio {
             &p0,
         )?;
         self.proxy.register_in_listener(p0).await?;
-        let conn = zbus::connection::Builder::unix_stream(p1)
-            .p2p()
-            .serve_at(
-                "/org/qemu/Display1/AudioInListener",
-                AudioInListener { handler },
-            )?;
+        let conn = zbus::connection::Builder::unix_stream(p1).p2p().serve_at(
+            "/org/qemu/Display1/AudioInListener",
+            AudioInListener { handler },
+        )?;
         #[cfg(windows)]
         let conn = conn.auth_mechanism(zbus::AuthMechanism::Anonymous);
         let conn = conn.build().await?;
diff --git a/qemu-display/src/console.rs b/qemu-display/src/console.rs
index 3b8104a..3a3ca61 100644
--- a/qemu-display/src/console.rs
+++ b/qemu-display/src/console.rs
@@ -118,9 +118,7 @@ impl Console {
             .serve_at("/org/qemu/Display1/Listener", ConsoleListener::new(handler))?;
         #[cfg(windows)]
         let conn = conn.auth_mechanism(zbus::AuthMechanism::Anonymous);
-        let conn = conn
-            .build()
-            .await?;
+        let conn = conn.build().await?;
         *self.listener.write().unwrap() = Some(conn);
         Ok(())
     }
diff --git a/qemu-display/src/console_listener.rs b/qemu-display/src/console_listener.rs
index 2ae2c19..7c72952 100644
--- a/qemu-display/src/console_listener.rs
+++ b/qemu-display/src/console_listener.rs
@@ -1,6 +1,7 @@
 #[cfg(windows)]
-use crate::win32::Fd;
+use crate::win32::{Fd, Mmap};
 use derivative::Derivative;
+#[cfg(unix)]
 use memmap2::Mmap;
 use std::ops::Drop;
 #[cfg(windows)]
@@ -66,6 +67,7 @@ impl ScanoutMap {
         #[cfg(windows)]
         let desc = self.handle.as_raw_handle();
 
+        #[cfg(unix)]
         let mmap = unsafe {
             memmap2::MmapOptions::new()
                 .len(len)
@@ -73,6 +75,13 @@ impl ScanoutMap {
                 .map(desc)?
         };
 
+        #[cfg(windows)]
+        let mmap = {
+            use windows::Win32::Foundation::HANDLE;
+            let handle = HANDLE(desc as _);
+            Mmap::new(handle, offset.try_into().unwrap(), len)?
+        };
+
         Ok(ScanoutMmap {
             scanout: self,
             mmap,
diff --git a/qemu-display/src/win32.rs b/qemu-display/src/win32.rs
index 1692970..a09fce5 100644
--- a/qemu-display/src/win32.rs
+++ b/qemu-display/src/win32.rs
@@ -1,9 +1,13 @@
 use std::io;
+use tracing::warn;
 
 use windows::Win32::{
     Foundation::{CloseHandle, HANDLE},
     Networking::WinSock::{WSADuplicateSocketW, SOCKET, WSAPROTOCOL_INFOW},
-    System::Threading::PROCESS_ACCESS_RIGHTS,
+    System::{
+        Memory::{MapViewOfFile, UnmapViewOfFile, FILE_MAP_READ, MEMORY_MAPPED_VIEW_ADDRESS},
+        Threading::PROCESS_ACCESS_RIGHTS,
+    },
 };
 
 #[cfg(feature = "qmp")]
@@ -118,3 +122,49 @@ pub(crate) fn unix_stream_get_peer_pid(stream: &UnixStream) -> Result<u32, std::
 
     Ok(ret)
 }
+
+#[derive(Debug)]
+pub(crate) struct Mmap {
+    handle: HANDLE,
+    ptr: MEMORY_MAPPED_VIEW_ADDRESS,
+    offset: isize,
+    size: usize,
+}
+
+#[cfg(windows)]
+impl Drop for Mmap {
+    fn drop(&mut self) {
+        unsafe {
+            if let Err(err) = UnmapViewOfFile(self.ptr) {
+                warn!("error while unmap: {}", err);
+            }
+            if let Err(err) = CloseHandle(self.handle) {
+                warn!("error while closing mmap: {}", err);
+            }
+        }
+    }
+}
+
+#[cfg(windows)]
+impl Mmap {
+    // FIXME: remove and replace with memmap2, use offset properly
+    // https://github.com/RazrFalcon/memmap2-rs/issues/138
+    pub(crate) fn new(handle: HANDLE, offset: usize, size: usize) -> std::io::Result<Self> {
+        let ptr = unsafe { MapViewOfFile(handle, FILE_MAP_READ, 0, 0, offset + size) };
+        if ptr.Value.is_null() {
+            return Err(io::Error::last_os_error());
+        }
+        Ok(Self {
+            handle,
+            ptr,
+            offset: offset.try_into().unwrap(),
+            size,
+        })
+    }
+
+    pub(crate) fn as_ref(&self) -> &[u8] {
+        unsafe {
+            std::slice::from_raw_parts(self.ptr.Value.cast::<u8>().offset(self.offset), self.size)
+        }
+    }
+}
diff --git a/qemu-rdw/src/display.rs b/qemu-rdw/src/display.rs
index be6dc59..bc2d09c 100644
--- a/qemu-rdw/src/display.rs
+++ b/qemu-rdw/src/display.rs
@@ -504,12 +504,10 @@ impl ConsoleListenerMapHandler for ConsoleHandler {
 #[cfg(windows)]
 #[async_trait::async_trait]
 impl ConsoleListenerD3d11Handler for ConsoleHandler {
-    #[cfg(windows)]
     async fn scanout_texture2d(&mut self, scanout: qemu_display::ScanoutD3dTexture2d) {
         self.send(ConsoleEvent::ScanoutD3dTexture2d(scanout));
     }
 
-    #[cfg(windows)]
     async fn update_texture2d(&mut self, update: qemu_display::UpdateD3dTexture2d) {
         let (wait_tx, wait_rx) = futures::channel::oneshot::channel();
         self.send(ConsoleEvent::UpdateD3dTexture2d { update, wait_tx });