Scatter gather list for data integrity
A system and method for improving message passing between a computer and peripheral devices is disclosed. The system and method for improving message passing between a computer and peripheral devices incorporate data checking on the command/message data and each scatter gather list element. The method in accordance with the present disclosure enables a peripheral device to check the integrity of the message and ownership of the scatter gather list element before the data is processed.
1. A method for generating a protected message with protected scatter gather list, the method comprising:
generating command data, the command data generated by a computer system for delivery to a peripheral device;
calculating a command protection value for the command data;
generating a scatter gather list element;
calculating a protection value for the scatter gather list element utilizing the command protection value for the command data as a seed value; and
sending the command data, the command protection value, the scatter gather list element and the protection value for the scatter gather list element to the peripheral device, wherein said calculating the command protection value and said calculating the protection value for the scatter gather list element match with at least one protection algorithm utilized by the peripheral device for calculating an expected command protection value and an expected protection value for the scatter gather list element, allowing the peripheral device to validate the command data and the scatter gather list element based on the command protection value and the protection value for the scatter gather list element and to perform a data operation specified in the scatter gather list element only when the command data and the scatter gather list element are validated.
2. The method of claim 1 , further comprising:
determining whether to generate an additional scatter gather list element;
generating the additional scatter gather list element;
calculating a protection value for the additional scatter gather list element utilizing the protection value for the first-mentioned scatter gather list element as the seed value; and
sending the command data, the command protection value, the scatter gather list elements and the protection values for the scatter gather list elements to the peripheral device.
3. The method of claim 1 , wherein the command data, the command protection value, the scatter gather list element and the protection value for the scatter gather list element are sent to the peripheral device via a system bus.
4. The method of claim 1 , wherein an application tag is utilized as an initial seed for calculating the command protection value for the command data.
5. A method for processing a message with scatter gather list, the method comprising:
receiving the message with scatter gather list from a computer system;
obtaining command data from the received message;
calculating an expected command protection value for the command data;
obtaining a command protection value from the received message;
determining whether the expected command protection value matches the command protection value obtained from the received message;
verifying data integrity of the scatter gather list when the expected command protection value matches the command protection value obtained from the received message, further comprising:
obtaining a scatter gather list element from the scatter gather list;
calculating an expected protection value for the scatter gather list element;
obtaining a protection value for the scatter gather list element from the received message;
determining whether the expected protection value for the scatter gather list element matches the protection value for the scatter gather list element obtained from the received message; and
performing a data operation specified in the scatter gather list element when the expected protection value for the scatter gather list element matches the protection value for the scatter gather list element obtained from the received message.
6. The method of claim 5 , wherein an application tag is utilized as an initial seed for calculating the expected command protection value for the command data.
7. The method of claim 5 , wherein the command protection value for the command data is utilized as a seed for calculating the expected protection value for the scatter gather list element.
8. The method of claim 5 , further comprising:
executing the command when the scatter gather list is verified successfully.
9. The method of claim 5 , further comprising:
halting the execution when the expected command protection value differs from the command protection value obtained from the received message.
10. The method of claim 5 , further comprising:
halting the execution and data operation when the expected protection value for the scatter gather list element differs from the protection value for the scatter gather list element obtained from the received message.
11. The method of claim 5 , further comprising:
obtaining an additional scatter gather list element from the scatter gather list;
calculating an expected protection value for the additional scatter gather list element;
obtaining a protection value for the additional scatter gather list element from the received message; and
determining whether the expected protection value for the additional scatter gather list element matches the protection value for the additional scatter gather list element obtained from the received message; and
performing an additional data operation specified in the additional scatter gather list element when the expected protection value for the additional scatter gather list element matches the protection value for the additional scatter gather list element obtained from the received message.
12. The method of claim 11 , further comprising:
halting the execution and data operation when the expected protection value for the additional scatter gather list element differs from the protection value for the additional scatter gather list element obtained from the received message.
13. The method of claim 11 , wherein the protection value for the first-mentioned scatter gather list element is utilized as the seed for calculating the expected protection value for the additional scatter gather list element.
14. A system, comprising:
a computer;
a peripheral device in communication with the computer via a system bus;
wherein the computer is configured for generating a message for delivery to the peripheral device, the message being generated according to the steps of:
generating command data;
calculating a command protection value for the command data;
generating at least one scatter gather list element;
calculating a protection value for the at least one scatter gather list element; and
sending the command data, the command protection value, the at least one scatter gather list element and the protection value for the at least one scatter gather list element to the peripheral device; and
wherein the peripheral device is configured for processing the message received from the computer, the message being processed according to the steps of:
obtaining the command data from the received message;
verifying data integrity of the command data;
obtaining the at least one scatter gather list element;
verifying data integrity of the at least one scatter gather list element; and
performing a data operation specified in the at least one scatter gather list element when the integrity of the at least one scatter gather list element is verified.
15. The system of claim 14 , wherein an application tag is utilized as an initial seed for calculating the command protection value for the command data.
16. The system of claim 14 , wherein the protection value for one of the at least one scatter gather list element is utilized as a seed for calculating the protection value for a subsequent one of the at least one scatter gather list element.
17. The system of claim 14 , wherein verifying data integrity of the command data comprises:
calculating an expected command protection value for the command data;
obtaining a command protection value from the received message; and
determining whether the expected command protection value matches the command protection value obtained from the received message.
18. The system of claim 17 , wherein the peripheral device is further configured for halting the execution when the expected command protection value differs from the command protection value obtained from the received message.
19. The system of claim 14 , wherein verifying data integrity of the at least one scatter gather list element comprises:
calculating an expected protection value for the at least one scatter gather list element;
obtaining a protection value for the at least one scatter gather list element from the received message;
determining whether the expected protection value for the at least one scatter gather list element matches the protection value for the scatter gather list element obtained from the received message.
20. The system of claim 19 , wherein the peripheral device is further configured for halting the execution and data operation when the expected protection value for the at least one scatter gather list element differs from the protection value for the at least one scatter gather list element obtained from the received message.