On Wed, May 22, 2019 at 08:05:50PM -0500, Katherine Rohl wrote:
> Hi,
>
> Adjusted NS8250 behavior in vmd(8) so it gets detected as an 8250 and not a
> 16450 by OpenBSD’s boot process. Also generalized some of the COM1-specific
> I/O address definitions to support adding COM2 (and COM3, and COM4…) in the
> future.
>
> Tested by logging into my VM with the virtual serial console and reinstalling
> 6.5, everything was fine. The boot process detected an NS8250.
>
Thanks for the vmd diff.
Please test with various Linux guests also. I added the scratch reg to make
this like an 8250A, IIRC, to support Linux guests. And you'll need to test
with a few, Alpine, Ubuntu, Centos, etc, as they all had different
behaviour. If those all work then we can get this in.
-ml
> Index: ns8250.c
> ===================================================================
> RCS file: /cvs/src/usr.sbin/vmd/ns8250.c,v
> retrieving revision 1.20
> diff -u -p -u -r1.20 ns8250.c
> --- ns8250.c 11 Mar 2019 17:08:52 -0000 1.20
> +++ ns8250.c 23 May 2019 00:52:15 -0000
> @@ -74,6 +74,7 @@ ns8250_init(int fd, uint32_t vmid)
> }
> com1_dev.fd = fd;
> com1_dev.irq = 4;
> + com1_dev.portid = NS8250_COM1;
> com1_dev.rcv_pending = 0;
> com1_dev.vmid = vmid;
> com1_dev.byte_out = 0;
> @@ -509,10 +510,10 @@ vcpu_process_com_scr(struct vm_exit *vei
> /*
> * vei_dir == VEI_DIR_OUT : out instruction
> *
> - * Write to SCR
> + * The 8250 does not have a scratch register.
> */
> if (vei->vei.vei_dir == VEI_DIR_OUT) {
> - com1_dev.regs.scr = vei->vei.vei_data;
> + com1_dev.regs.scr = 0xFF;
> } else {
> /*
> * vei_dir == VEI_DIR_IN : in instruction
> @@ -647,6 +648,7 @@ ns8250_restore(int fd, int con_fd, uint3
> }
> com1_dev.fd = con_fd;
> com1_dev.irq = 4;
> + com1_dev.portid = NS8250_COM1;
> com1_dev.rcv_pending = 0;
> com1_dev.vmid = vmid;
> com1_dev.byte_out = 0;
> Index: ns8250.h
> ===================================================================
> RCS file: /cvs/src/usr.sbin/vmd/ns8250.h,v
> retrieving revision 1.7
> diff -u -p -u -r1.7 ns8250.h
> --- ns8250.h 11 Mar 2019 17:08:52 -0000 1.7
> +++ ns8250.h 23 May 2019 00:52:15 -0000
> @@ -18,14 +18,30 @@
> /*
> * Emulated 8250 UART
> */
> -#define COM1_DATA 0x3f8
> -#define COM1_IER 0x3f9
> -#define COM1_IIR 0x3fa
> -#define COM1_LCR 0x3fb
> -#define COM1_MCR 0x3fc
> -#define COM1_LSR 0x3fd
> -#define COM1_MSR 0x3fe
> -#define COM1_SCR 0x3ff
> +#define COM1_BASE 0x3f8
> +#define COM1_DATA COM1_BASE+COM_OFFSET_DATA
> +#define COM1_IER COM1_BASE+COM_OFFSET_IER
> +#define COM1_IIR COM1_BASE+COM_OFFSET_IIR
> +#define COM1_LCR COM1_BASE+COM_OFFSET_LCR
> +#define COM1_MCR COM1_BASE+COM_OFFSET_MCR
> +#define COM1_LSR COM1_BASE+COM_OFFSET_LSR
> +#define COM1_MSR COM1_BASE+COM_OFFSET_MSR
> +#define COM1_SCR COM1_BASE+COM_OFFSET_SCR
> +
> +#define COM_OFFSET_DATA 0
> +#define COM_OFFSET_IER 1
> +#define COM_OFFSET_IIR 2
> +#define COM_OFFSET_LCR 3
> +#define COM_OFFSET_MCR 4
> +#define COM_OFFSET_LSR 5
> +#define COM_OFFSET_MSR 6
> +#define COM_OFFSET_SCR 7
> +
> +/* ns8250 port identifier */
> +enum ns8250_portid {
> + NS8250_COM1,
> + NS8250_COM2,
> +};
>
> /* ns8250 UART registers */
> struct ns8250_regs {
> @@ -50,6 +66,7 @@ struct ns8250_dev {
> struct event rate;
> struct event wake;
> struct timeval rate_tv;
> + enum ns8250_portid portid;
> int fd;
> int irq;
> int rcv_pending;
>
