Commit 0bbe4ced authored by Adrian Huang's avatar Adrian Huang Committed by Joerg Roedel
Browse files

iommu/amd: Fix the overwritten field in IVMD header 



Commit 387caf0b ("iommu/amd: Treat per-device exclusion
ranges as r/w unity-mapped regions") accidentally overwrites
the 'flags' field in IVMD (struct ivmd_header) when the I/O
virtualization memory definition is associated with the
exclusion range entry. This leads to the corrupted IVMD table
(incorrect checksum). The kdump kernel reports the invalid checksum:

ACPI BIOS Warning (bug): Incorrect checksum in table [IVRS] - 0x5C, should be 0x60 (20200717/tbprint-177)
AMD-Vi: [Firmware Bug]: IVRS invalid checksum

Fix the above-mentioned issue by modifying the 'struct unity_map_entry'
member instead of the IVMD header.

Cleanup: The *exclusion_range* functions are not used anymore, so
get rid of them.

Fixes: 387caf0b ("iommu/amd: Treat per-device exclusion ranges as r/w unity-mapped regions")
Reported-and-tested-by: default avatarBaoquan He <bhe@redhat.com>
Signed-off-by: default avatarAdrian Huang <ahuang12@lenovo.com>
Cc: Jerry Snitselaar <jsnitsel@redhat.com>
Link: https://lore.kernel.org/r/20200926102602.19177-1-adrianhuang0701@gmail.com


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 1a260449

drivers/iommu/amd/init.c

+10 −46
Original line number Diff line number Diff line
@@ -1103,25 +1103,6 @@ static int __init add_early_maps(void) 
	return 0;

}



/*

 * Reads the device exclusion range from ACPI and initializes the IOMMU with

 * it

 */

static void __init set_device_exclusion_range(u16 devid, struct ivmd_header *m)

{

	if (!(m->flags & IVMD_FLAG_EXCL_RANGE))

		return;



	/*

	 * Treat per-device exclusion ranges as r/w unity-mapped regions

	 * since some buggy BIOSes might lead to the overwritten exclusion

	 * range (exclusion_start and exclusion_length members). This

	 * happens when there are multiple exclusion ranges (IVMD entries)

	 * defined in ACPI table.

	 */

	m->flags = (IVMD_FLAG_IW | IVMD_FLAG_IR | IVMD_FLAG_UNITY_MAP);

}



/*

 * Takes a pointer to an AMD IOMMU entry in the ACPI table and

 * initializes the hardware and our data structures with it.
@@ -2073,30 +2054,6 @@ static void __init free_unity_maps(void) 
	}

}



/* called when we find an exclusion range definition in ACPI */

static int __init init_exclusion_range(struct ivmd_header *m)

{

	int i;



	switch (m->type) {

	case ACPI_IVMD_TYPE:

		set_device_exclusion_range(m->devid, m);

		break;

	case ACPI_IVMD_TYPE_ALL:

		for (i = 0; i <= amd_iommu_last_bdf; ++i)

			set_device_exclusion_range(i, m);

		break;

	case ACPI_IVMD_TYPE_RANGE:

		for (i = m->devid; i <= m->aux; ++i)

			set_device_exclusion_range(i, m);

		break;

	default:

		break;

	}



	return 0;

}



/* called for unity map ACPI definition */

static int __init init_unity_map_range(struct ivmd_header *m)

{
@@ -2107,9 +2064,6 @@ static int __init init_unity_map_range(struct ivmd_header *m) 
	if (e == NULL)

		return -ENOMEM;



	if (m->flags & IVMD_FLAG_EXCL_RANGE)

		init_exclusion_range(m);



	switch (m->type) {

	default:

		kfree(e);
@@ -2133,6 +2087,16 @@ static int __init init_unity_map_range(struct ivmd_header *m) 
	e->address_end = e->address_start + PAGE_ALIGN(m->range_length);

	e->prot = m->flags >> 1;



	/*

	 * Treat per-device exclusion ranges as r/w unity-mapped regions

	 * since some buggy BIOSes might lead to the overwritten exclusion

	 * range (exclusion_start and exclusion_length members). This

	 * happens when there are multiple exclusion ranges (IVMD entries)

	 * defined in ACPI table.

	 */

	if (m->flags & IVMD_FLAG_EXCL_RANGE)

		e->prot = (IVMD_FLAG_IW | IVMD_FLAG_IR) >> 1;



	DUMP_printk("%s devid_start: %02x:%02x.%x devid_end: %02x:%02x.%x"

		    " range_start: %016llx range_end: %016llx flags: %x\n", s,

		    PCI_BUS_NUM(e->devid_start), PCI_SLOT(e->devid_start),

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