On Fri, Mar 03, 2023 at 12:31:42PM +0100, Thomas Huth wrote:
On 03/03/2023 12.16, Peter Maydell wrote:
On Thu, 2 Mar 2023 at 16:31, Thomas Huth <thuth@redhat.com> wrote:
qemu-system-aarch64 is a proper superset of qemu-system-arm, and the latter was mainly still required for 32-bit KVM support. But this 32-bit KVM arm support has been dropped in the Linux kernel a couple of years ago already, so we don't really need qemu-system-arm anymore, thus deprecated it now.
Signed-off-by: Thomas Huth <thuth@redhat.com> --- docs/about/deprecated.rst | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst index a30aa8dfdf..21ce70b5c9 100644 --- a/docs/about/deprecated.rst +++ b/docs/about/deprecated.rst @@ -45,6 +45,16 @@ run 32-bit guests by selecting a 32-bit CPU model, including KVM support on x86_64 hosts. Thus users are recommended to reconfigure their systems to use the ``qemu-system-x86_64`` binary instead.
+``qemu-system-arm`` binary (since 8.0) +'''''''''''''''''''''''''''''''''''''' + +``qemu-system-aarch64`` is a proper superset of ``qemu-system-arm``.
I think this is not quite true -- at the moment if you want "every feature we implement, 32-bit" the only way to get that is 'qemu-system-arm -cpu max'. The '-cpu max' on qemu-system-aarch64 is 64-bit, and we don't implement for TCG the "-cpu max,aarch64=off" syntax that we do for KVM that would let the user say "no 64-bit support".
Ok ... so what does that mean now? ... can we continue with this patch, e.g. after rephrasing the text a little bit, or do we need to implement "-cpu max,aarch64=off" for TCG first?
I think we need to have a way to request the max 32-bit CPU before we deprecate, because deprecation has to tell people what they should use instead. For qemu-system-i686 -cpu max, I guess we have lm=off to hide the 64-bit support, so that's OK from QEMU POV, but will need libvirt enhancement as I don't think we've taken that into account. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|