[v2] cxl: Add kernel API to allow a context to operate with relocate disabled
mpe at ellerman.id.au
Wed May 11 07:48:40 AEST 2016
On Fri, 2016-06-05 at 07:46:36 UTC, Ian Munsie wrote:
> From: Ian Munsie <imunsie at au1.ibm.com>
> cxl devices typically access memory using an MMU in much the same way as
> the CPU, and each context includes a state register much like the MSR in
> the CPU. Like the CPU, the state register includes a bit to enable
> relocation, which we currently always enable.
> In some cases, it may be desirable to allow a device to access memory
> using real addresses instead of effective addresses, so this adds a new
> API, cxl_set_translation_mode, that can be used to disable relocation
> on a given kernel context. This can allow for the creation of a special
> privileged context that the device can use if it needs relocation
> disabled, and can use regular contexts at times when it needs relocation
> This interface is only available to users of the kernel API for obvious
> reasons, and will never be supported in a virtualised environment.
> This will be used by the upcoming cxl support in the mlx5 driver.
> Signed-off-by: Ian Munsie <imunsie at au1.ibm.com>
Applied to powerpc next, thanks.
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