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From: Andre Przywara <andre.przywara@arm.com>
To: Stefano Stabellini <sstabellini@kernel.org>
Cc: xen-devel@lists.xenproject.org,
	Julien Grall <julien.grall@arm.com>,
	Shanker Donthineni <shankerd@codeaurora.org>,
	Vijay Kilari <vijay.kilari@gmail.com>
Subject: Re: [PATCH v3 02/26] ARM: GICv3: allocate LPI pending and property table
Date: Mon, 3 Apr 2017 10:05:31 +0100	[thread overview]
Message-ID: <4a85303a-e5a8-ff48-a93e-32fb73b6d85a@arm.com> (raw)
In-Reply-To: <alpine.DEB.2.10.1703311557380.3287@sstabellini-ThinkPad-X260>

Hi,

On 31/03/17 23:59, Stefano Stabellini wrote:
> On Fri, 31 Mar 2017, Andre Przywara wrote:
>> The ARM GICv3 provides a new kind of interrupt called LPIs.
>> The pending bits and the configuration data (priority, enable bits) for
>> those LPIs are stored in tables in normal memory, which software has to
>> provide to the hardware.
>> Allocate the required memory, initialize it and hand it over to each
>> redistributor. The maximum number of LPIs to be used can be adjusted with
>> the command line option "max_lpi_bits", which defaults to 20 bits,
>> covering about one million LPIs.
>>
>> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
>> ---

[...]

>> +static unsigned int max_lpi_bits = 20;
>> +integer_param("max_lpi_bits", max_lpi_bits);
> 
> The only thing missing is checking that the user has passed max_lpi_bits
> or warn if she has not (or if the memory usage is too high).

Right, I was missing that.
So I went with the "if memory usage is too high" version here, since the
default of 20 bits results in a 16KB first level table only. I would
then start warning if the bits exceed 24 (which is 256KB).
From what I could learn, the ARM GIC-500 provides 16 bits of LPIs, and
Cavium advertises 20 bits, AFAIK (hence the default).
I don't know about other platforms or future machines, though, so we
should keep this in.

> Look at the way dom0_mem is implemented.

Thanks!
Andre.

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  reply	other threads:[~2017-04-03  9:03 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-31 18:04 [PATCH v3 00/26] arm64: Dom0 ITS emulation Andre Przywara
2017-03-31 18:05 ` [PATCH v3 01/26] ARM: GICv3 ITS: parse and store ITS subnodes from hardware DT Andre Przywara
2017-03-31 23:08   ` Stefano Stabellini
2017-03-31 18:05 ` [PATCH v3 02/26] ARM: GICv3: allocate LPI pending and property table Andre Przywara
2017-03-31 22:59   ` Stefano Stabellini
2017-04-03  9:05     ` Andre Przywara [this message]
2017-04-03 18:16       ` Stefano Stabellini
2017-04-03 13:53   ` Julien Grall
2017-04-03 14:01     ` Julien Grall
2017-03-31 18:05 ` [PATCH v3 03/26] ARM: GICv3 ITS: allocate device and collection table Andre Przywara
2017-03-31 23:06   ` Stefano Stabellini
2017-04-03 15:38   ` Julien Grall
2017-04-03 17:22     ` Julien Grall
2017-04-03 19:39       ` Andre Przywara
2017-04-03 20:46         ` Julien Grall
2017-03-31 18:05 ` [PATCH v3 04/26] ARM: GICv3 ITS: map ITS command buffer Andre Przywara
2017-03-31 23:10   ` Stefano Stabellini
2017-04-03 16:00   ` Julien Grall
2017-03-31 18:05 ` [PATCH v3 05/26] ARM: GICv3 ITS: introduce ITS command handling Andre Przywara
2017-03-31 23:16   ` Stefano Stabellini
2017-04-03 17:32   ` Julien Grall
2017-03-31 18:05 ` [PATCH v3 06/26] ARM: GICv3 ITS: introduce device mapping Andre Przywara
2017-03-31 23:20   ` Stefano Stabellini
2017-04-01  8:01   ` Vijay Kilari
2017-04-03 18:33     ` Julien Grall
2017-04-03 18:56   ` Julien Grall
2017-03-31 18:05 ` [PATCH v3 07/26] ARM: GICv3 ITS: introduce host LPI array Andre Przywara
2017-03-31 23:24   ` Stefano Stabellini
2017-03-31 18:05 ` [PATCH v3 08/26] ARM: GICv3: introduce separate pending_irq structs for LPIs Andre Przywara
2017-03-31 18:05 ` [PATCH v3 09/26] ARM: GICv3: forward pending LPIs to guests Andre Przywara
2017-03-31 18:05 ` [PATCH v3 10/26] ARM: GICv3: enable ITS and LPIs on the host Andre Przywara
2017-03-31 18:05 ` [PATCH v3 11/26] ARM: vGICv3: handle virtual LPI pending and property tables Andre Przywara
2017-04-04 12:55   ` Julien Grall
2017-04-04 12:56     ` Julien Grall
2017-03-31 18:05 ` [PATCH v3 12/26] ARM: vGICv3: Handle disabled LPIs Andre Przywara
2017-03-31 18:05 ` [PATCH v3 13/26] ARM: vGICv3: introduce basic ITS emulation bits Andre Przywara
2017-03-31 18:05 ` [PATCH v3 14/26] ARM: vITS: introduce translation table walks Andre Przywara
2017-03-31 18:05 ` [PATCH v3 15/26] ARM: vITS: handle CLEAR command Andre Przywara
2017-03-31 18:05 ` [PATCH v3 16/26] ARM: vITS: handle INT command Andre Przywara
2017-03-31 18:05 ` [PATCH v3 17/26] ARM: vITS: handle MAPC command Andre Przywara
2017-03-31 18:05 ` [PATCH v3 18/26] ARM: vITS: handle MAPD command Andre Przywara
2017-03-31 18:05 ` [PATCH v3 19/26] ARM: vITS: handle MAPTI command Andre Przywara
2017-04-01  8:32   ` Vijay Kilari
2017-03-31 18:05 ` [PATCH v3 20/26] ARM: vITS: handle MOVI command Andre Przywara
2017-03-31 18:05 ` [PATCH v3 21/26] ARM: vITS: handle DISCARD command Andre Przywara
2017-03-31 18:05 ` [PATCH v3 22/26] ARM: vITS: handle INV command Andre Przywara
2017-03-31 18:05 ` [PATCH v3 23/26] ARM: vITS: handle INVALL command Andre Przywara
2017-03-31 18:05 ` [PATCH v3 24/26] ARM: vITS: create and initialize virtual ITSes for Dom0 Andre Przywara
2017-03-31 18:05 ` [PATCH v3 25/26] ARM: vITS: create ITS subnodes for Dom0 DT Andre Przywara
2017-03-31 18:05 ` [PATCH v3 26/26] ARM: vGIC: advertise LPI support Andre Przywara
2017-04-04 17:06   ` Julien Grall
2017-04-01 20:37 ` [PATCH v3 00/26] arm64: Dom0 ITS emulation Julien Grall

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