[PATCH] docs/system: clarify pflash0 and pflash1 are virt-only options

[Linisha <linisha232@gmail.com>]

The pflash0 and pflash1 machine options shown in the Aarch64 virt example are only available for virt machine types on Arm, RISC-V, and LoongArch architectures. Add a note to clarify this for users who may try these options on x86 machines and be confused when they are not available.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3254
Signed-off-by: Linisha <linisha232@gmail.com>
---
 docs/system/introduction.rst | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/docs/system/introduction.rst b/docs/system/introduction.rst
index bec7291e47..0c400aefb6 100644
--- a/docs/system/introduction.rst
+++ b/docs/system/introduction.rst
@@ -158,6 +158,12 @@ virtualisation so we can use KVM inside the emulated guest. As the
 ``virt`` machine comes with some built in pflash devices we give them
 names so we can override the defaults later.
 
+.. note::
+   The ``pflash0`` and ``pflash1`` machine options are specific to the
+   ``virt`` machine type on Arm, RISC-V, and LoongArch architectures.
+   They are not available on x86 machines, which use ``-bios`` or
+   ``-pflash`` for firmware instead.
+
 .. code::
 
  $ qemu-system-aarch64 \
-- 
2.47.0.windows.1