Re: [Minios-devel] [UNIKRAFT PATCH 2/2] plat/kvm: Update VGA console cursor location

[Florian Schmidt <florian@xxxxxxxxx>]

On 07/29/2018 12:39 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
And I just realized this isn't very clear. This of course sets the 
"Cursor Location {High,Low}" registers, but it doesn't set the "Cursor 
{Start,End}" registers. I won't send a v2 for just that. Waiting for 
other potential comments instead.
> get is the blinking underline character, not the full-size block
> character.
>
> Signed-off-by: Florian Schmidt <florian.schmidt@xxxxxxxxx>
> ---
>   plat/kvm/x86/vga_console.c | 33 +++++++++++++++++++++++++++++++++
>   1 file changed, 33 insertions(+)
>
> diff --git a/plat/kvm/x86/vga_console.c b/plat/kvm/x86/vga_console.c
> index a1b5cf7..efcddde 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. */
> @@ -109,6 +111,36 @@ static void vga_scroll(void)
>                         = vga_entry(' ', terminal_color);
>   }
>   
> +static void vga_update_cursor(void)
> +{
> +       unsigned long irq_flags;
> +       uint8_t old;
> +       uint8_t ioas;  // VGA Input/Output select
> +       uint16_t areg; // VGA address register
> +       uint16_t dreg; // VGA data register
> +
> +       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.
> +        */
> +       ioas = inb(0x3cc) & 0x1;
> +       if (ioas) {
> +               areg = 0x3d4;
> +               dreg = 0x3d5;
> +       } else {
> +               areg = 0x3b4;
> +               dreg = 0x3b5;
> +       }
> +
> +       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)
> @@ -160,4 +192,5 @@ void _libkvmplat_vga_putc(char c)
>                 }
>                 break;
>         }
> +       vga_update_cursor();
>   }
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