Hi Lorenzo,
On 05/23/2017 06:06 PM, Lorenzo Pieralisi wrote:
[+Al]
On Tue, May 23, 2017 at 05:40:28PM +0100, Julien Grall wrote:
Hi all,
I am currently looking at adding support of ACPI 5.1 in Xen.
When trying to boot DOM00 I get a panic in Linux (for the full
log see [1]):
(XEN) DOM0: [ 0.000000] No valid GICC entries exist
The error message is coming from gic_v2_acpi_init.
Digging down in the code, it is failing because of
BAD_MADT_GICC_ENTRY is returning false in
gic_acpi_parse_madt_cpu:
/* Macros for consistency checks of the GICC subtable of MADT */
#define ACPI_MADT_GICC_LENGTH \
(acpi_gbl_FADT.header.revision < 6 ? 76 : 80)
#define BAD_MADT_GICC_ENTRY(entry, end)
\
(!(entry) || (unsigned long)(entry) + sizeof(*(entry)) > (end) || \
(entry)->header.length != ACPI_MADT_GICC_LENGTH)
The 'end' parameter corresponds to the end of the MADT table.
In the case of ACPI 5.1, the size of GICC is smaller compare
to 6.0+ (76 vs 80 bytes) but the parameter 'entry' is type
of acpi_madt_generic_interrupt (sizeof(...) = 80).
#define BAD_MADT_GICC_ENTRY(entry, end) \
(!(entry) || (entry)->header.length != ACPI_MADT_GICC_LENGTH || \
((unsigned long)(entry) + ACPI_MADT_GICC_LENGTH) > (end))
Would this solve it ?
Yes, I am now able to boot DOM0 up to the prompt. My concern with this
solution is the code will still use the acpi_madt_generic_interrupt
code. If someone tries to access field not existing in 5.1 (such as
efficiency_class), it may return wrong value or even worst crash.
Although, I don't see any user of efficiency_class in Linux so far.
Cheers,
--
Julien Grall
