On 2022/5/6 03:46, Steve Wahl wrote:
Increase DMAR_UNITS_SUPPORTED to support 64 sockets with 10 DMAR units
each, for a total of 640.
If the available hardware exceeds DMAR_UNITS_SUPPORTED (previously set
to MAX_IO_APICS, or 128), it causes these messages: "DMAR: Failed to
allocate seq_id", "DMAR: Parse DMAR table failure.", and "x2apic: IRQ
remapping doesn't support X2APIC mode x2apic disabled"; and the system
fails to boot.
Signed-off-by: Steve Wahl <steve.w...@hpe.com>
Reviewed-by: Mike Travis <mike.tra...@hpe.com>
---
Note that we could not find a reason for connecting
DMAR_UNITS_SUPPORTED to MAX_IO_APICS as was done previously. Perhaps
it seemed like the two would continue to match on earlier processors.
There doesn't appear to be kernel code that assumes that the value of
one is related to the other.
+Kevin
This maximum value was introduced by below commit. And I don't see any
hardware/software restrictions that we can't enlarge it after ten years.
commit 1b198bb04ad72669d4bd6575fc9945ed595bfee0
Author: Mike Travis <tra...@sgi.com>
Date: Mon Mar 5 15:05:16 2012 -0800
x86/iommu/intel: Increase the number of iommus supported to
MAX_IO_APICS
The number of IOMMUs supported should be the same as the number
of IO APICS. This limit comes into play when the IOMMUs are
identity mapped, thus the number of possible IOMMUs in the
"static identity" (si) domain should be this same number.
[...]
include/linux/dmar.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/dmar.h b/include/linux/dmar.h
index 45e903d84733..9d4867b8f42e 100644
--- a/include/linux/dmar.h
+++ b/include/linux/dmar.h
@@ -19,7 +19,7 @@
struct acpi_dmar_header;
#ifdef CONFIG_X86
-# define DMAR_UNITS_SUPPORTED MAX_IO_APICS
+# define DMAR_UNITS_SUPPORTED 640
#else
# define DMAR_UNITS_SUPPORTED 64
#endif
Best regards,
baolu
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