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MPAMCFG_MBW_PBM, MPAM Bandwidth Portion Bitmap Partition Configuration Register

The MPAMCFG_MBW_PBM characteristics are:


The MPAMCFG_MBW_PBM register is a read-write register that configures the cache portions that a PARTID is allowed to allocate. MPAMCFG_MBW_PBM_s controls the bandwidth portion bitmap for the Secure PARTID selected by the Secure instance of MPAMCFG_PART_SEL. MPAMCFG_MBW_PBM_ns controls the bandwidth portion bitmap for the Non-secure PARTID selected by the Non-secure instance of MPAMCFG_PART_SEL.

After setting MPAMCFG_PART_SEL with a PARTID, software (usually a hypervisor) writes to the MPAMCFG_CPBM register to configure which cache portions the PARTID is allowed to allocate.



This register is present only when MPAMF_IDR.HAS_MBW_PART == 1 and MPAMF_MBW_IDR.HAS_PBM == 1. Otherwise, direct accesses to MPAMCFG_MBW_PBM are RES0.


MPAMCFG_MBW_PBM is a 4096-bit register.

Field descriptions

The MPAMCFG_MBW_PBM bit assignments are:

BWPBM<n>, bit [n], for n = 0 to 4095

Each bit BWPBM<n> grants permission to the PARTID to allocate bandwidth within bandwidth portion n.


The PARTID is not permitted to allocate into bandwidth portion n.


The PARTID is permitted to allocate within bandwidth portion n.

The number of bits in the bandwidth portion partitioning bit map of this component is given in MPAMF_MBW_IDR.BWPBM_WD. BWPBM_WD contains a value from 1 to 212, inclusive. Values of BWPBM_WD greater than 32 require a group of 32-bit registers to access the BWPBM, up to 128 32-bit registers.

Bits BWPBM<n>, where n is greater than BWPBM_WD, are not required to be implemented.

Accessing the MPAMCFG_MBW_PBM

This register is within the MPAM feature page memory frames. In a system that supports Secure and Non-secure memory maps, there must be both Secure and Non-secure MPAM feature pages.

MPAMCFG_MBW_PBM_s must be accessible from the Secure MPAM feature page. MPAMCFG_MBW_PBM_ns must be accessible from the Non-secure MPAM feature page.

MPAMCFG_MBW_PBM_s and MPAMCFG_MBW_PBM_ns must be separate registers. The Secure instance (MPAMCFG_MBW_PBM_s) accesses the memory bandwidth portion bitmaps used for Secure PARTIDs, and the Non-secure instance (MPAMCFG_MBW_PBM_ns) accesses the memory bandwidth portion bitmaps used for Non-secure PARTIDs.

MPAMCFG_MBW_PBM can be accessed through the memory-mapped interfaces:


Accesses on this interface are RW.


Accesses on this interface are RW.

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