Address translation for input/output devices using hierarchical translation tables

Method comprising:

• indexing a table structure by a source identifier of an input/output (I/O) transaction specifying a guest physical address and requested by an I/O device to map the I/O device to a domain assigned to the I/O device, indexing the table structure comprising indexing a root table storing root entries by the source identifier, and mapping the I/O device to the domain by referencing a context table using the root entries, the context table storing context entries, indexing the root table comprising indicating if the each of the root entries is present using a root present indicator, and referencing the context table using a context table pointer;
• and
• translating the guest physical address to a host physical address corresponding to the I/O transaction using an address translation structure;
• wherein mapping the I/O device comprises:
• indicating if the each of the context entries is present using a context present indicator;
• identifying the domain using a domain identifier;
• defining size of a physical address space of the domain using a guest address width;
• and
• defining base of the physical address space of the domain or a page table in the address translation structure using an address space root.

A system comprising:

• a memory;
• an input/output (I/O) device requesting an I/O transaction, the I/O device having a source identifier, the I/O transaction specifying a guest physical address;
• a chipset coupled to the I/O device, the chipset including a remapping circuit, the remapping circuit comprising:
• a table structure indexed by the source identifier to map the I/O device to a domain assigned to the I/O device in the memory, the table structure comprising a root table to store root entries indexed by the source identifier, and a context table coupled to the root table to store context entries referenced by the root entries, the context entries mapping the I/O device to the domain, each of the root entries comprising a root present indicator to indicate if the each of the root entries is present, and a context table pointer to reference the context table, and
• an address translation structure coupled to the table structure to translate the guest physical address to a host physical address corresponding to the I/O transaction;
• wherein each of the context entries comprises:
• a context present indicator to indicate if the each of the context entries is present;
• a domain identifier to identify the domain;
• a guest address width to define size of a physical address space of the domain;
• and
• an address space root to define base of the physical address space of the domain or a page table in the address translation structure.

An article of manufacture comprising:

• a machine-accessible storage medium including data that, when accessed by a machine, cause the machine to perform operations comprising:
• indexing a table structure by a source identifier of an input/output (I/O) transaction specifying a guest physical address and requested by an I/O device to map the I/O device to a domain assigned to the I/O device, indexing the table structure comprising indexing a root table storing root entries by the source identifier, and mapping the I/O device to the domain by referencing a context table using the root entries, the context table storing context entries, indexing the root table comprising indicating if the each of the root entries is present using a root present indicator, and referencing the context table using a context table pointer;
• and
• translating the guest physical address to a host physical address corresponding to the I/O transaction using an address translation structure;
• wherein the data causing the machine to perform mapping the I/O device comprises data that cause the machine to perform operations comprising:
• indicating if the each of the context entries is present using a context present indicator;
• identifying the domain using a domain identifier;
• defining size of a physical address space of the domain using a guest address width;
• and
• defining base of the physical address space of the domain or a page table in the address translation structure using an address space root.