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ahci.c: mask unused flags when reading size PRDT DBC

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The data byte count(DBC) read from the description information is defined for
bits 21:00. Bits 30:22 are reserved and bit 31 is the Interrupt on Completion
(I) flag.

Completion interrupts are triggered after every transaction instead of on
I-flag in QEMU. tbl_entry_size is a signed integer and improperly reading the
DBC leads to a negative offset that causes sglist allocation to fail.

Signed-off-by: Reza Jelveh <reza.jelveh@tuhh.de>
Reviewed-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Reza Jelveh 2014-07-01 13:13:27 +02:00 committed by Stefan Hajnoczi
parent 37253e1ec8
commit d02f8adc6d
2 changed files with 10 additions and 3 deletions
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11
hw/ide/ahci.c
View File

@ -639,6 +639,11 @@ static void ahci_write_fis_d2h(AHCIDevice *ad, uint8_t *cmd_fis)
}
}
static int prdt_tbl_entry_size(const AHCI_SG *tbl)
{
return (le32_to_cpu(tbl->flags_size) & AHCI_PRDT_SIZE_MASK) + 1;
}
static int ahci_populate_sglist(AHCIDevice *ad, QEMUSGList *sglist, int offset)
{
AHCICmdHdr *cmd = ad->cur_cmd;
@ -681,7 +686,7 @@ static int ahci_populate_sglist(AHCIDevice *ad, QEMUSGList *sglist, int offset)
sum = 0;
for (i = 0; i < sglist_alloc_hint; i++) {
/* flags_size is zero-based */
tbl_entry_size = (le32_to_cpu(tbl[i].flags_size) + 1);
tbl_entry_size = prdt_tbl_entry_size(&tbl[i]);
if (offset <= (sum + tbl_entry_size)) {
off_idx = i;
off_pos = offset - sum;
@ -700,12 +705,12 @@ static int ahci_populate_sglist(AHCIDevice *ad, QEMUSGList *sglist, int offset)
qemu_sglist_init(sglist, qbus->parent, (sglist_alloc_hint - off_idx),
ad->hba->as);
qemu_sglist_add(sglist, le64_to_cpu(tbl[off_idx].addr + off_pos),
le32_to_cpu(tbl[off_idx].flags_size) + 1 - off_pos);
prdt_tbl_entry_size(&tbl[off_idx]) - off_pos);
for (i = off_idx + 1; i < sglist_alloc_hint; i++) {
/* flags_size is zero-based */
qemu_sglist_add(sglist, le64_to_cpu(tbl[i].addr),
le32_to_cpu(tbl[i].flags_size) + 1);
prdt_tbl_entry_size(&tbl[i]));
}
}

2
hw/ide/ahci.h
View File

@ -201,6 +201,8 @@
#define AHCI_COMMAND_TABLE_ACMD 0x40
#define AHCI_PRDT_SIZE_MASK 0x3fffff
#define IDE_FEATURE_DMA 1
#define READ_FPDMA_QUEUED 0x60