Hi Denis, Thank you for the patch.
On Tue, Sep 9, 2025 at 12:12 AM <[email protected]> wrote: > > From: Denis Mukhin <[email protected]> > > Add SCR register emulation to the I/O port handler. > Firmware (e.g. OVMF) may use SCR during the guest OS boot. > > Signed-off-by: Denis Mukhin <[email protected]> > --- > Changes since v6: > - default handling of non-DLL/DLM registers moved to the previous patch > --- > xen/common/emul/vuart/ns16x50.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/xen/common/emul/vuart/ns16x50.c b/xen/common/emul/vuart/ns16x50.c > index da8583a1dc93..5643ef4cc01e 100644 > --- a/xen/common/emul/vuart/ns16x50.c > +++ b/xen/common/emul/vuart/ns16x50.c > @@ -106,6 +106,11 @@ static int ns16x50_io_write8( > { > switch ( reg ) > { > + /* NB: Firmware (e.g. OVMF) may rely on SCR presence. */ > + case UART_SCR: > + regs[UART_SCR] = val; > + break; > + > default: > rc = -EINVAL; > break; > @@ -177,6 +182,10 @@ static int ns16x50_io_read8( > { > switch ( reg ) > { > + case UART_SCR: > + val = regs[UART_SCR]; > + break; > + > default: > rc = -EINVAL; > break; > -- > 2.51.0 > > Reviewed-by: Mykola Kvach <[email protected]> Best regards, Mykola
