Re: PCI Express

From: Colin Ngam <>
Date: 2005-03-10 05:12:37
Nguyen, Tom L wrote:

>On Tue, Mar 08, 2005 at 05:29:13PM -0800, Jesse Barnes wrote:
>>An MSI should behave like a processor sending an IPI to itself since
>>address can be targeted at the processor's interrupt block and set to 
>>generate a local interrupt.  Is that right, Tom & Grant?
>MSI address is programmed at 0xfeex_xxxx (based on PCI Specs) to
Hi Tom,

The MSI address portion allows 64bits for the address.  It should be an 
address whereby a specific Platform has configured with sufficient 
information to generate an Interrupt to the targeted "cpu" with the 
payload - IRQ.

I am very much interested in your assertion that the MSI address is 
defined by PCI Spec to be 0xfeex_xxxx.  Can you kindly point me to the 
relevent section?  Perhaps if you have an online copy, can you cut and 
paste the relevent section?



>generate a memory write to FSB. This address can be configured to target
>a platform interrupt controller (like IOAPIC for example), which in turn
>generates a memory write to a FSB, or be configured to send a memory
>write directly to FSB. Existing MSI support implements a direct
>memory-write mechanism (generic solution without platform dependency and
>limitation to MSI-X support as an example). With existing direct
>memory-write mechanism, a device's MSI address is configured with
>current running CPU as a target. MSI support also implements MSI SMP
>affinity, which supports IRQ rebalance and allows user to select which
>CPU target through /proc/irq/...
>I hope it helps.

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Received on Wed Mar 9 13:15:05 2005

This archive was generated by hypermail 2.1.8 : 2005-08-02 09:20:36 EST