Merge patch series "x86: Improve operation under QEMU"

Simon Glass <sjg@chromium.org> says:

U-Boot can start and boot an OS in both qemu-x86 and qemu-x86_64 but it
is not perfect.

With both builds, executing the VESA ROM causes an intermittent hang, at
least on some AMD CPUs.

With qemu-x86_64 kvm cannot be used since the move to long mode (64-bit)
is done in a way that works on real hardware but not with QEMU. This
means that performance is 4-5x slower than it could be, at least on my
CPU.

We can work around the first problem by using Bochs, which is anyway a
better choice than VESA for QEMU. The second can be addressed by using
the same descriptor across the jump to long mode.

With an MTRR fix this allows booting into Ubuntu on qemu-x86_64

In v3 some e820 patches are included to make booting reliable and avoid
ACPI tables being dropped. Also, several MTTR problems are addressed, to
support memory sizes above 4GB reliably.

Link: https://lore.kernel.org/all/20250315142643.2600605-1-sjg@chromium.org/

1 files changed, 17 insertions, 8 deletions

diff --git a/test/py/console_base.py b/test/py/console_base.py
index 260df773bac..88d444b44b8 100644
--- a/test/py/console_base.py
+++ b/test/py/console_base.py
@@ -370,21 +370,30 @@ class ConsoleBase(object):
             output.append(self.run_command(cmd))
         return output
 
-    def ctrlc(self):
-        """Send a CTRL-C character to U-Boot.
+    def send(self, msg):
+        """Send characters without waiting for echo, etc."""
+        self.run_command(msg, wait_for_prompt=False, wait_for_echo=False,
+                         send_nl=False)
+
+    def ctrl(self, char):
+        """Send a CTRL- character to U-Boot.
 
         This is useful in order to stop execution of long-running synchronous
         commands such as "ums".
 
         Args:
-            None.
-
-        Returns:
-            Nothing.
+            char (str): Character to send, e.g. 'C' to send Ctrl-C
         """
+        self.log.action(f'Sending Ctrl-{char}')
+        self.send(chr(ord(char) - ord('@')))
 
-        self.log.action('Sending Ctrl-C')
-        self.run_command(chr(3), wait_for_echo=False, send_nl=False)
+    def ctrlc(self):
+        """Send a CTRL-C character to U-Boot.
+
+        This is useful in order to stop execution of long-running synchronous
+        commands such as "ums".
+        """
+        self.ctrl('C')
 
     def wait_for(self, text):
         """Wait for a pattern to be emitted by U-Boot.