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vmm/amd: improve iteration over IVHD (type 10h) entries in IVRS table

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Many 8-byte entries have zero at byte 4, so the second 4-byte part is
skipped as a 4-byte padding entry.  But not all 8-byte entries have that
property and they get misinterpreted.

A real example:
    48 00 00 00 ff 01 00 01
This an 8-byte ACPI_IVRS_TYPE_SPECIAL entry for IOAPIC with ID 255 (bogus).
It is reported as:
    ivhd0: Unknown dev entry:0xff
Fortunately, it was completely harmless.

Also, bail out early if we encounter an entry of a variable length type.
We do not have proper handling for those yet.

Reviewed by:	anish
This commit is contained in:
Andriy Gapon 2017-11-24 11:10:36 +00:00
parent fd74a38251
commit 8523ad24ba
1 changed files with 19 additions and 7 deletions
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26
sys/amd64/vmm/amd/ivrs_drv.c
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@ -186,7 +186,8 @@ ivhd_dev_add_entry(struct amdvi_softc *softc, uint32_t start_id,
static int
ivhd_dev_parse(ACPI_IVRS_HARDWARE * ivhd, struct amdvi_softc *softc)
{
ACPI_IVRS_DE_HEADER *de, *end;
ACPI_IVRS_DE_HEADER *de;
uint8_t *p, *end;
int range_start_id = 0, range_end_id = 0;
uint32_t *extended;
uint8_t all_data = 0, range_data = 0;
@ -195,12 +196,15 @@ ivhd_dev_parse(ACPI_IVRS_HARDWARE * ivhd, struct amdvi_softc *softc)
softc->start_dev_rid = ~0;
softc->end_dev_rid = 0;
de = (ACPI_IVRS_DE_HEADER *) ((uint8_t *)ivhd +
sizeof(ACPI_IVRS_HARDWARE));
end = (ACPI_IVRS_DE_HEADER *) ((uint8_t *)ivhd +
ivhd->Header.Length);
/*
* XXX The following actually depends on Header.Type and
* is only true for 0x10.
*/
p = (uint8_t *)ivhd + sizeof(ACPI_IVRS_HARDWARE);
end = (uint8_t *)ivhd + ivhd->Header.Length;
while (de < (ACPI_IVRS_DE_HEADER *) end) {
while (p < end) {
de = (ACPI_IVRS_DE_HEADER *)p;
softc->start_dev_rid = MIN(softc->start_dev_rid, de->Id);
softc->end_dev_rid = MAX(softc->end_dev_rid, de->Id);
switch (de->Type) {
@ -263,7 +267,15 @@ ivhd_dev_parse(ACPI_IVRS_HARDWARE * ivhd, struct amdvi_softc *softc)
"WARN Too many device entries.\n");
return (EINVAL);
}
de++;
if (de->Type < 0x40)
p += sizeof(ACPI_IVRS_DEVICE4);
else if (de->Type < 0x80)
p += sizeof(ACPI_IVRS_DEVICE8A);
else {
printf("Variable size IVHD type 0x%x not supported\n",
de->Type);
break;
}
}
KASSERT((softc->end_dev_rid >= softc->start_dev_rid),