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atapi: classify read_cd as conditionally returning data 

For the purposes of byte_count_limit verification, add a new flag that
identifies read_cd as sometimes returning data, then check the BCL in
its command handler after we know that it will indeed return data.

Reported-by: Hervé Poussineau <hpoussin@reactos.org>
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 1477970211-25754-2-git-send-email-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
This commit is contained in:
John Snow 2016-11-14 11:15:54 -05:00
parent 83c83f9a52
commit e7bd708ec8
1 changed files with 40 additions and 11 deletions
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51
hw/ide/atapi.c
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@ -637,6 +637,23 @@ static unsigned int event_status_media(IDEState *s,
return 8; /* We wrote to 4 extra bytes from the header */
}
/*
* Before transferring data or otherwise signalling acceptance of a command
* marked CONDDATA, we must check the validity of the byte_count_limit.
*/
static bool validate_bcl(IDEState *s)
{
/* TODO: Check IDENTIFY data word 125 for defacult BCL (currently 0) */
if (s->atapi_dma || atapi_byte_count_limit(s)) {
return true;
}
/* TODO: Move abort back into core.c and introduce proper error flow between
* ATAPI layer and IDE core layer */
ide_abort_command(s);
return false;
}
static void cmd_get_event_status_notification(IDEState *s,
uint8_t *buf)
{
@ -1028,12 +1045,19 @@ static void cmd_read_cd(IDEState *s, uint8_t* buf)
return;
}
transfer_request = buf[9];
switch(transfer_request & 0xf8) {
case 0x00:
transfer_request = buf[9] & 0xf8;
if (transfer_request == 0x00) {
/* nothing */
ide_atapi_cmd_ok(s);
break;
return;
}
/* Check validity of BCL before transferring data */
if (!validate_bcl(s)) {
return;
}
switch (transfer_request) {
case 0x10:
/* normal read */
ide_atapi_cmd_read(s, lba, nb_sectors, 2048);
@ -1266,6 +1290,14 @@ enum {
* See ATA8-ACS3 "7.21.5 Byte Count Limit"
*/
NONDATA = 0x04,
/*
* CONDDATA implies a command that transfers data only conditionally based
* on the presence of suboptions. It should be exempt from the BCL check at
* command validation time, but it needs to be checked at the command
* handler level instead.
*/
CONDDATA = 0x08,
};
static const struct AtapiCmd {
@ -1289,7 +1321,7 @@ static const struct AtapiCmd {
[ 0xad ] = { cmd_read_dvd_structure, CHECK_READY },
[ 0xbb ] = { cmd_set_speed, NONDATA },
[ 0xbd ] = { cmd_mechanism_status, 0 },
[ 0xbe ] = { cmd_read_cd, CHECK_READY },
[ 0xbe ] = { cmd_read_cd, CHECK_READY | CONDDATA },
/* [1] handler detects and reports not ready condition itself */
};
@ -1348,15 +1380,12 @@ void ide_atapi_cmd(IDEState *s)
return;
}
/* Nondata commands permit the byte_count_limit to be 0.
/* Commands that don't transfer DATA permit the byte_count_limit to be 0.
* If this is a data-transferring PIO command and BCL is 0,
* we abort at the /ATA/ level, not the ATAPI level.
* See ATA8 ACS3 section 7.17.6.49 and 7.21.5 */
if (cmd->handler && !(cmd->flags & NONDATA)) {
/* TODO: Check IDENTIFY data word 125 for default BCL (currently 0) */
if (!(atapi_byte_count_limit(s) || s->atapi_dma)) {
/* TODO: Move abort back into core.c and make static inline again */
ide_abort_command(s);
if (cmd->handler && !(cmd->flags & (NONDATA | CONDDATA))) {
if (!validate_bcl(s)) {
return;
}
}