Re: [kvm-unit-tests PATCH 3/3] lib: s390x: sclp: Add line mode input handling

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

On Tue, 10 Oct 2023 07:38:55 +0000
Janosch Frank <frankja@linux.ibm.com> wrote:

> Time to add line-mode input so we can use input handling under LPAR if
> there's no access to a ASCII console.
> 
> Line-mode IO is pretty wild and the documentation could be improved a
> lot. Hence I've copied the input parsing functions from Linux.
> 
> For some reason output is a type 2 event but input is a type 1
> event. This also means that the input and output structures are
> different from each other.
> 
> The input can consist of multiple structures which don't contain text
> data before the input text data is reached. Hence we need a bunch of
> search functions to retrieve a pointer to the text data.
> 
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> ---
>  lib/s390x/sclp-console.c | 180 ++++++++++++++++++++++++++++++++++-----
>  lib/s390x/sclp.h         |  26 +++++-
>  2 files changed, 185 insertions(+), 21 deletions(-)
> 
> diff --git a/lib/s390x/sclp-console.c b/lib/s390x/sclp-console.c
> index 313be1e4..23c09b70 100644
> --- a/lib/s390x/sclp-console.c
> +++ b/lib/s390x/sclp-console.c
> @@ -1,8 +1,12 @@
>  /* SPDX-License-Identifier: GPL-2.0-or-later */
>  /*
> - * SCLP ASCII access driver
> + * SCLP line mode and ASCII console driver
>   *
>   * Copyright (c) 2013 Alexander Graf <agraf@suse.de>
> + *
> + * Copyright IBM Corp. 1999
> + * Author(s): Martin Peschke <mpeschke@de.ibm.com>
> + *	      Martin Schwidefsky <schwidefsky@de.ibm.com>

from the weird copyright notices that you are adding I deduce that you
copied those functions from the kernel. maybe add a line in the patch
description to say so? or at least explain better in the comment itself.

>   */
>  
>  #include <libcflat.h>
> @@ -86,6 +90,41 @@ static uint8_t _ascebc[256] = {
>       0x90, 0x3F, 0x3F, 0x3F, 0x3F, 0xEA, 0x3F, 0xFF
>  };
>  
> +static const uint8_t _ebcasc[] = {
> +	0x00, 0x01, 0x02, 0x03, 0x07, 0x09, 0x07, 0x7F,
> +	0x07, 0x07, 0x07, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
> +	0x10, 0x11, 0x12, 0x13, 0x07, 0x0A, 0x08, 0x07,
> +	0x18, 0x19, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
> +	0x07, 0x07, 0x1C, 0x07, 0x07, 0x0A, 0x17, 0x1B,
> +	0x07, 0x07, 0x07, 0x07, 0x07, 0x05, 0x06, 0x07,
> +	0x07, 0x07, 0x16, 0x07, 0x07, 0x07, 0x07, 0x04,
> +	0x07, 0x07, 0x07, 0x07, 0x14, 0x15, 0x07, 0x1A,
> +	0x20, 0xFF, 0x83, 0x84, 0x85, 0xA0, 0x07, 0x86,
> +	0x87, 0xA4, 0x5B, 0x2E, 0x3C, 0x28, 0x2B, 0x21,
> +	0x26, 0x82, 0x88, 0x89, 0x8A, 0xA1, 0x8C, 0x07,
> +	0x8D, 0xE1, 0x5D, 0x24, 0x2A, 0x29, 0x3B, 0x5E,
> +	0x2D, 0x2F, 0x07, 0x8E, 0x07, 0x07, 0x07, 0x8F,
> +	0x80, 0xA5, 0x07, 0x2C, 0x25, 0x5F, 0x3E, 0x3F,
> +	0x07, 0x90, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
> +	0x70, 0x60, 0x3A, 0x23, 0x40, 0x27, 0x3D, 0x22,
> +	0x07, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,
> +	0x68, 0x69, 0xAE, 0xAF, 0x07, 0x07, 0x07, 0xF1,
> +	0xF8, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F, 0x70,
> +	0x71, 0x72, 0xA6, 0xA7, 0x91, 0x07, 0x92, 0x07,
> +	0xE6, 0x7E, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,
> +	0x79, 0x7A, 0xAD, 0xAB, 0x07, 0x07, 0x07, 0x07,
> +	0x9B, 0x9C, 0x9D, 0xFA, 0x07, 0x07, 0x07, 0xAC,
> +	0xAB, 0x07, 0xAA, 0x7C, 0x07, 0x07, 0x07, 0x07,
> +	0x7B, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
> +	0x48, 0x49, 0x07, 0x93, 0x94, 0x95, 0xA2, 0x07,
> +	0x7D, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50,
> +	0x51, 0x52, 0x07, 0x96, 0x81, 0x97, 0xA3, 0x98,
> +	0x5C, 0xF6, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
> +	0x59, 0x5A, 0xFD, 0x07, 0x99, 0x07, 0x07, 0x07,
> +	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
> +	0x38, 0x39, 0x07, 0x07, 0x9A, 0x07, 0x07, 0x07,
> +};
> +
>  static bool lpar_ascii_compat;
>  
>  static char lm_buff[120];
> @@ -224,7 +263,8 @@ static void sclp_write_event_mask(int receive_mask, int send_mask)
>  
>  static void sclp_console_enable_read(void)
>  {
> -	sclp_write_event_mask(SCLP_EVENT_MASK_MSG_ASCII, SCLP_EVENT_MASK_MSG_ASCII | SCLP_EVENT_MASK_MSG);
> +	sclp_write_event_mask(SCLP_EVENT_MASK_MSG_ASCII | SCLP_EVENT_MASK_OPCMD,
> +			      SCLP_EVENT_MASK_MSG_ASCII | SCLP_EVENT_MASK_MSG);
>  }
>  
>  static void sclp_console_disable_read(void)
> @@ -262,37 +302,137 @@ void sclp_print(const char *str)
>  	sclp_print_lm(str);
>  }
>  
> +static char *console_read_ascii(struct EventBufferHeader *ebh, int *len)
> +{
> +	struct ReadEventDataAsciiConsole *evdata = (void *)ebh;
> +	const int max_event_buffer_len = SCCB_SIZE - offsetof(ReadEventDataAsciiConsole, ebh);
> +	const int event_buffer_ascii_recv_header_len = offsetof(ReadEventDataAsciiConsole, data);
> +
> +	assert(ebh->length <= max_event_buffer_len);
> +	assert(ebh->length > event_buffer_ascii_recv_header_len);
> +
> +	*len = ebh->length - event_buffer_ascii_recv_header_len;
> +	return evdata->data;
> +}
> +
> +
> +static struct gds_vector *sclp_find_gds_vector(void *start, void *end, uint16_t id)
> +{
> +	struct gds_vector *v;
> +
> +	for (v = start; (void *)v < end; v = (void *)v + v->length)
> +		if (v->gds_id == id)
> +			return v;
> +	return NULL;
> +}
> +
> +static struct gds_subvector *sclp_eval_selfdeftextmsg(struct gds_subvector *sv)
> +{
> +	void *end;
> +
> +	end = (void *)sv + sv->length;
> +	for (sv = sv + 1; (void *)sv < end; sv = (void *)sv + sv->length)
> +		if (sv->key == 0x30)
> +			return sv;
> +	return NULL;
> +}
> +
> +static struct gds_subvector *sclp_eval_textcmd(struct gds_vector *v)
> +{
> +	struct gds_subvector *sv;
> +	void *end;
> +
> +	end = (void *)v + v->length;
> +	for (sv = (struct gds_subvector *)(v + 1); (void *)sv < end;
> +	     sv = (void *)sv + sv->length)
> +		if (sv->key == GDS_KEY_SELFDEFTEXTMSG)
> +			return sclp_eval_selfdeftextmsg(sv);
> +	return NULL;
> +}
> +
> +static struct gds_subvector *sclp_eval_cpmsu(struct gds_vector *v)
> +{
> +	void *end;
> +
> +	end = (void *)v + v->length;
> +	for (v = v + 1; (void *)v < end; v = (void *)v + v->length)
> +		if (v->gds_id == GDS_ID_TEXTCMD)
> +			return sclp_eval_textcmd(v);
> +	return NULL;
> +}
> +
> +static struct gds_subvector *sclp_eval_mdsmu(struct gds_vector *v)
> +{
> +	v = sclp_find_gds_vector(v + 1, (void *)v + v->length, GDS_ID_CPMSU);
> +	if (v)
> +		return sclp_eval_cpmsu(v);
> +	return NULL;
> +}
> +
> +static char *console_read_lm(struct EventBufferHeader *ebh, int *len)
> +{
> +	struct gds_vector *v = (void *)ebh + sizeof(*ebh);
> +	struct gds_subvector *sv;
> +
> +	v = sclp_find_gds_vector(v, (void *)ebh + ebh->length,
> +				 GDS_ID_MDSMU);
> +	if (!v)
> +		return NULL;
> +
> +	sv = sclp_eval_mdsmu(v);
> +	if (!sv)
> +		return NULL;
> +
> +	*len = sv->length - (sizeof(*sv));
> +	return (char *)(sv + 1);
> +}
> +
> +static void ebc_to_asc(char *data, int len)
> +{
> +	int i;
> +
> +	for (i = 0; i < len; i++)
> +		data[i] = _ebcasc[(uint8_t)data[i]];
> +}
> +
>  static int console_refill_read_buffer(void)
>  {
> -	const int max_event_buffer_len = SCCB_SIZE - offsetof(ReadEventDataAsciiConsole, ebh);
> -	ReadEventDataAsciiConsole *sccb = (void *)_sccb;
> -	const int event_buffer_ascii_recv_header_len = sizeof(sccb->ebh) + sizeof(sccb->type);
> -	int ret = -1;
> +	struct SCCBHeader *sccb = (struct SCCBHeader *)_sccb;
> +	struct EventBufferHeader *ebh = (void *)_sccb + sizeof(struct SCCBHeader);
> +	char *data;
> +	int ret = -1, len;
>  
>  	sclp_console_enable_read();
>  
>  	sclp_mark_busy();
> -	memset(sccb, 0, SCCB_SIZE);
> -	sccb->h.length = PAGE_SIZE;
> -	sccb->h.function_code = SCLP_UNCONDITIONAL_READ;
> -	sccb->h.control_mask[2] = SCLP_CM2_VARIABLE_LENGTH_RESPONSE;
> +	memset(_sccb, 0, SCCB_SIZE);
> +	sccb->length = PAGE_SIZE;
> +	sccb->function_code = SCLP_UNCONDITIONAL_READ;
> +	sccb->control_mask[2] = SCLP_CM2_VARIABLE_LENGTH_RESPONSE;
>  
>  	sclp_service_call(SCLP_CMD_READ_EVENT_DATA, sccb);
>  
> -	if (sccb->h.response_code == SCLP_RC_NO_EVENT_BUFFERS_STORED ||
> -	    sccb->ebh.type != SCLP_EVENT_ASCII_CONSOLE_DATA ||
> -	    sccb->type != SCLP_EVENT_ASCII_TYPE_DATA_STREAM_FOLLOWS) {
> -		ret = -1;
> +	if (sccb->response_code == SCLP_RC_NO_EVENT_BUFFERS_STORED)
> +		goto out;
> +
> +	switch (ebh->type) {
> +	case SCLP_EVENT_OP_CMD:
> +		data = console_read_lm(ebh, &len);
> +		if (data)
> +			ebc_to_asc(data, len);
> +		break;
> +	case SCLP_EVENT_ASCII_CONSOLE_DATA:
> +		data = console_read_ascii(ebh, &len);
> +		break;
> +	default:
>  		goto out;
>  	}
>  
> -	assert(sccb->ebh.length <= max_event_buffer_len);
> -	assert(sccb->ebh.length > event_buffer_ascii_recv_header_len);
> +	if (!data)
> +		goto out;
>  
> -	read_buf_length = sccb->ebh.length - event_buffer_ascii_recv_header_len;
> -
> -	assert(read_buf_length <= sizeof(read_buf));
> -	memcpy(read_buf, sccb->data, read_buf_length);
> +	assert(len <= sizeof(read_buf));
> +	memcpy(read_buf, data, len);
>  
>  	read_index = 0;
>  	ret = 0;
> diff --git a/lib/s390x/sclp.h b/lib/s390x/sclp.h
> index 6a611bc3..22f120d1 100644
> --- a/lib/s390x/sclp.h
> +++ b/lib/s390x/sclp.h
> @@ -226,6 +226,7 @@ typedef struct SCCB {
>  } __attribute__((packed)) SCCB;
>  
>  /* SCLP event types */
> +#define SCLP_EVENT_OP_CMD			0x01
>  #define SCLP_EVENT_ASCII_CONSOLE_DATA           0x1a
>  #define SCLP_EVENT_SIGNAL_QUIESCE               0x1d
>  
> @@ -233,6 +234,7 @@ typedef struct SCCB {
>  #define SCLP_EVENT_MASK_SIGNAL_QUIESCE          0x00000008
>  #define SCLP_EVENT_MASK_MSG_ASCII               0x00000040
>  #define SCLP_EVENT_MASK_MSG          		0x40000000
> +#define SCLP_EVENT_MASK_OPCMD			0x80000000
>  
>  #define SCLP_UNCONDITIONAL_READ                 0x00
>  #define SCLP_SELECTIVE_READ                     0x01
> @@ -296,6 +298,23 @@ struct mdb {
>  	struct mto mto;
>  } __attribute__((packed));
>  
> +/* vector keys and ids */
> +#define GDS_ID_MDSMU		0x1310
> +#define GDS_ID_CPMSU		0x1212
> +#define GDS_ID_TEXTCMD		0x1320
> +#define GDS_KEY_SELFDEFTEXTMSG	0x31
> +#define EBC_MDB                 0xd4c4c240
> +
> +struct gds_vector {
> +	uint16_t     length;
> +	uint16_t     gds_id;
> +} __attribute__((packed));
> +
> +struct gds_subvector {
> +	uint8_t      length;
> +	uint8_t      key;
> +} __attribute__((packed));
> +
>  typedef struct EventBufferHeader {
>  	uint16_t length;
>  	uint8_t  type;
> @@ -320,12 +339,17 @@ typedef struct ReadEventData {
>  
>  #define SCLP_EVENT_ASCII_TYPE_DATA_STREAM_FOLLOWS 0
>  typedef struct ReadEventDataAsciiConsole {
> -	SCCBHeader h;
>  	EventBufferHeader ebh;
>  	uint8_t type;
>  	char data[];
>  } __attribute__((packed)) ReadEventDataAsciiConsole;
>  
> +struct ReadEventDataLMConsole {
> +	SCCBHeader h;
> +	EventBufferHeader ebh;
> +	struct gds_vector v[];
> +};
> +
>  extern char _sccb[];
>  void sclp_setup_int(void);
>  void sclp_handle_ext(void);