Re: [Minios-devel] [UNIKRAFT PATCH v2 1/1] plat/kvm: Update VGA console cursor location

[Simon Kuenzer <simon.kuenzer@xxxxxxxxx>]

Reviewed-by: Simon Kuenzer <simon.kuenzer@xxxxxxxxx>

On 22.08.2018 15:54, Florian Schmidt wrote:
> On 08/22/2018 03:51 PM, Florian Schmidt wrote:
> > Update the location of the cursor as data is written to the console.
> > Note that this does not set the cursor location registers, hence all we
> > get is the blinking underline character, not the full-size block
> > character.
> ... aaand I forgot to update the commit message. Just ignore the second 
> sentence, it should only be the first one.
It is fine. I am going to remove the second sentence from the message.

> Sorry,
> Florian
Thanks,

Simon

> > Signed-off-by: Florian Schmidt <florian.schmidt@xxxxxxxxx>
> > ---
> >   plat/kvm/x86/vga_console.c | 47 ++++++++++++++++++++++++++++++++++++++
> >   1 file changed, 47 insertions(+)
> >
> > diff --git a/plat/kvm/x86/vga_console.c b/plat/kvm/x86/vga_console.c
> > index ff825e3..f565b1c 100644
> > --- a/plat/kvm/x86/vga_console.c
> > +++ b/plat/kvm/x86/vga_console.c
> > @@ -29,6 +29,8 @@
> >   #include <sys/types.h>
> >   #include <stdint.h>
> >   #include <string.h>
> > +#include <x86/cpu.h>
> > +#include <x86/irq.h>
> >   #include <kvm-x86/vga_console.h>
> >   /* Hardware text mode color constants. */
> > @@ -69,6 +71,8 @@ static size_t terminal_row;
> >   static size_t terminal_column;
> >   static uint8_t terminal_color;
> >   static uint16_t *terminal_buffer;
> > +static uint16_t areg;   /* VGA address register */
> > +static uint16_t dreg;   /* VGA data register */
> >   static void clear_terminal(void)
> >   {
> > @@ -83,9 +87,36 @@ static void clear_terminal(void)
> >   void _libkvmplat_init_vga_console(void)
> >   {
> > +    unsigned long irq_flags;
> > +
> >       terminal_row = 0;
> >       terminal_column = 0;
> >       terminal_color = vga_entry_color(VGA_COLOR_LIGHT_GREY, 
> > VGA_COLOR_BLACK);
> > +
> > +    local_irq_save(irq_flags);
> > +    /* Location of the address and data registers is variable and 
> > denoted
> > +     * by the least significant bit in the Input/Output register located
> > +     * at 0x3cc. For our emulated color display, they should always be
> > +     * 0x3d{4,5}, but better safe than sorry, so let's check at init 
> > time.
> > +     */
> > +    if (inb(0x3cc) & 0x1) {
> > +        areg = 0x3d4;
> > +        dreg = 0x3d5;
> > +    } else {
> > +        areg = 0x3b4;
> > +        dreg = 0x3b5;
> > +    }
> > +
> > +    /* Initialize cursor appearance. Setting CURSOR_START (0x0a) to 0x0e
> > +     * and CURSOR_END (0x0b) to 0x0f enables the cursor and produces
> > +     * a blinking underscore.
> > +     */
> > +    outb(areg, 0x0a);
> > +    outb(dreg, 0x0e);
> > +    outb(areg, 0x0b);
> > +    outb(dreg, 0x0f);
> > +    local_irq_restore(irq_flags);
> > +
> >       terminal_buffer = (uint16_t *) 0xb8000;
> >       clear_terminal();
> >   }
> > @@ -109,6 +140,21 @@ static void vga_scroll(void)
> >               = vga_entry(' ', terminal_color);
> >   }
> > +static void vga_update_cursor(void)
> > +{
> > +    unsigned long irq_flags;
> > +    uint8_t old;
> > +
> > +    local_irq_save(irq_flags);
> > +    old = inb(areg);
> > +    outb(areg, 0x0e); // Cursor Location High
> > +    outb(dreg, ((terminal_row * VGA_WIDTH) + terminal_column) >> 8);
> > +    outb(areg, 0x0f); // Cursor Location Low
> > +    outb(dreg, ((terminal_row * VGA_WIDTH) + terminal_column) & 0xff);
> > +    outb(areg, old);
> > +    local_irq_restore(irq_flags);
> > +}
> > +
> >   static void vga_newline(void)
> >   {
> >       if (terminal_row == VGA_HEIGHT - 1)
> > @@ -157,4 +203,5 @@ void _libkvmplat_vga_putc(char c)
> >           }
> >           break;
> >       }
> > +    vga_update_cursor();
> >   }
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