Re: [Clax86list] Accessing Physical Memory & Other Process's Address Space

On Wed, 6 Feb 2008 10:00:52 -0800 (PST)
"mybwpp@xxxxxxxxxxxxxx" <spamtrap@xxxxxxxxxx> wrote:

What does 1234h imply here, is it the linear address (virtual memory
address) in the process own address space or physical address?

Virtual address.

how a process can
refer to the memory location in another process address space (both
operating at the same privilege level)?

Such a process would have to determine what physical address was
currently assigned to the target virtual address and map that physical
address into its own virtual address space, which would require both a
system privilege level, and a detailed knowledge of the OS internals.

On the other hand, the OS may offer such a service to processes which
wish to share a common memory range. In Linux, for example, this is done by
issuing an mmap request with the MAP_SHARED attribute.

Is there any way to directly refer to physical memory locations in
mov or similar instructions?

Not while paging is enabled.

--
Chuck
http://www.pacificsites.com/~ccrayne/charles.html

.

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