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From: Haren Myneni <haren@linux.ibm.com>
To: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>,
	mpe@ellerman.id.au, hch@infradead.org, mikey@neuling.org,
	npiggin@gmail.com, herbert@gondor.apana.org.au,
	linuxppc-dev@lists.ozlabs.org, devicetree@vger.kernel.org,
	sukadev@linux.vnet.ibm.com
Subject: Re: [PATCH V2 00/13] powerpc/vas: Page fault handling for user space NX requests
Date: Wed, 11 Dec 2019 21:05:38 -0800	[thread overview]
Message-ID: <1576127138.16318.43.camel@hbabu-laptop> (raw)
In-Reply-To: <20191209083806.GA3152@gate.crashing.org>

On Mon, 2019-12-09 at 02:38 -0600, Segher Boessenkool wrote:
> Hi!
> 
> On Mon, Dec 09, 2019 at 06:37:09AM +0100, Christophe Leroy wrote:
> > What do you mean by NX ?
> 
> It is the Power9 "Nest Accelerator".  The patch series should ideally
> mention that right at the start, yeah.

Thanks, NX (Nest Accelerator) is introduced since power7+
(drivers/crypto/nx/)

Whereas on power9, VAS (Virtual Accelerator Switchboard) is introduced
which allows to open multiple channels to communicate with NX. kernel or
user space can interact with NX directly using copy/paste instructions.
Kernel support with NX-842 compression is already included in kernel. 

In the case of user space, NX can see page fault on the request buffer
and interrupts OS to handle this fault. This patch series adds page
fault handling in VAS for user space requests. 

I will repost this patch with more explanation on NX. 

> 
> > Up to now, NX has been standing for No-eXecute. That's a bit in segment 
> > registers on book3s/32 to forbid executing code.
> 
> That bit is called just N fwiw (and not really specific to 32-bit -- on
> 64-bit implementations it was part of segment table entries, and of SLB
> entries on newer machines).
> 
> 
> Segher



  reply	other threads:[~2019-12-12  5:08 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-09  3:18 [PATCH V2 00/13] powerpc/vas: Page fault handling for user space NX requests Haren Myneni
2019-12-09  3:26 ` [PATCH V2 01/13] powerpc/vas: Describe vas-port and interrupts properties Haren Myneni
2019-12-09  3:27 ` [PATCH V2 02/13] powerpc/vas: Define nx_fault_stamp in coprocessor_request_block Haren Myneni
2019-12-09  3:29 ` [PATCH V2 03/13] powerpc/vas: Read interrupts and vas-port device tree properties Haren Myneni
2019-12-09  3:30 ` [PATCH V2 04/13] powerpc/vas: Setup fault window per VAS instance Haren Myneni
2019-12-12 12:55   ` Christoph Hellwig
2019-12-09  3:31 ` [PATCH V2 05/13] powerpc/vas: Setup thread IRQ handler " Haren Myneni
2019-12-12 12:59   ` Christoph Hellwig
2019-12-09  3:32 ` [PATCH V2 06/13] powerpc/vas: Register NX with fault window ID and IRQ port value Haren Myneni
2019-12-09  3:32 ` [PATCH V2 07/13] powerpc/vas: Take reference to PID and mm for user space windows Haren Myneni
2019-12-12 13:02   ` Christoph Hellwig
2019-12-17  5:35     ` Haren Myneni
2019-12-09  3:33 ` [PATCH V2 08/13] powerpc/vas: Update CSB and notify process for fault CRBs Haren Myneni
2019-12-12 13:07   ` Christoph Hellwig
2019-12-09  3:34 ` [PATCH V2 09/13] powerpc/vas: Print CRB and FIFO values Haren Myneni
2019-12-09  3:34 ` [PATCH V2 10/13] powerpc/vas: Do not use default credits for receive window Haren Myneni
2019-12-09  3:35 ` [PATCH V2 11/13] powerpc/vas: Return credits after handling fault Haren Myneni
2019-12-09  3:36 ` [PATCH V2 12/13] powerpc/vas: Display process stuck message Haren Myneni
2019-12-09  3:37 ` [PATCH V2 13/13] powerpc/vas: Free send window in VAS instance after credits returned Haren Myneni
2019-12-09  5:37 ` [PATCH V2 00/13] powerpc/vas: Page fault handling for user space NX requests Christophe Leroy
2019-12-09  8:38   ` Segher Boessenkool
2019-12-12  5:05     ` Haren Myneni [this message]
2019-12-12  5:38 ` Haren Myneni

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