Messages in this thread | | | Subject | Re: irqchip/irq-gic: BAD_MADT_GICC_ENTRY may fail when booting with ACPI 5.1 | From | Julien Grall <> | Date | Wed, 24 May 2017 12:18:09 +0100 |
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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
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