From: Dan Williams <dan.j.williams@intel.com>
To: Ben Widawsky <ben.widawsky@intel.com>
Cc: linux-cxl@vger.kernel.org, patches@lists.linux.dev,
Alison Schofield <alison.schofield@intel.com>,
Ira Weiny <ira.weiny@intel.com>,
Jonathan Cameron <Jonathan.Cameron@huawei.com>,
Vishal Verma <vishal.l.verma@intel.com>,
Bjorn Helgaas <helgaas@kernel.org>,
Linux NVDIMM <nvdimm@lists.linux.dev>,
Linux PCI <linux-pci@vger.kernel.org>
Subject: Re: [PATCH v3 06/14] cxl/region: Address space allocation
Date: Fri, 18 Feb 2022 11:51:33 -0800 [thread overview]
Message-ID: <CAPcyv4jnbch=LdyNwMJ9WWQNGNnE3gqC5msLUBc3ncUXE6+15w@mail.gmail.com> (raw)
In-Reply-To: <20220128002707.391076-7-ben.widawsky@intel.com>
On Thu, Jan 27, 2022 at 4:27 PM Ben Widawsky <ben.widawsky@intel.com> wrote:
>
> When a region is not assigned a host physical address,
Curious, is there a way to pick one in the current ABI? Not that I
want one, in fact I think Linux should make it as difficult as
possible to create a region with a fixed address (per the 'HPA' field
of the region label) given all the problems it can cause with decoder
allocation ordering. Unless and until someone identifies a solid use
case for that capability it should be de-emphasized.
> one is picked by
> the driver. As the address will determine which CFMWS contains the
> region, it's usually a better idea to let the driver make this
> determination.
>
> Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
> ---
> drivers/cxl/region.c | 40 ++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 38 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/cxl/region.c b/drivers/cxl/region.c
> index cc41939a2f0a..5588873dd250 100644
> --- a/drivers/cxl/region.c
> +++ b/drivers/cxl/region.c
> @@ -1,6 +1,7 @@
> // SPDX-License-Identifier: GPL-2.0-only
> /* Copyright(c) 2021 Intel Corporation. All rights reserved. */
> #include <linux/platform_device.h>
> +#include <linux/genalloc.h>
> #include <linux/device.h>
> #include <linux/module.h>
> #include <linux/pci.h>
> @@ -64,6 +65,20 @@ static struct cxl_port *get_root_decoder(const struct cxl_memdev *endpoint)
> return NULL;
> }
>
> +static void release_cxl_region(void *r)
> +{
> + struct cxl_region *cxlr = (struct cxl_region *)r;
> + struct cxl_decoder *rootd = rootd_from_region(cxlr);
> + struct resource *res = &rootd->platform_res;
> + resource_size_t start, size;
> +
> + start = cxlr->res->start;
> + size = resource_size(cxlr->res);
> +
> + __release_region(res, start, size);
> + gen_pool_free(rootd->address_space, start, size);
If the need to keep the gen_pool in sync is dropped then this
open-coded devm release handler can be replaced with
__devm_request_region().
> +}
> +
> /**
> * sanitize_region() - Check is region is reasonably configured
> * @cxlr: The region to check
> @@ -129,8 +144,29 @@ static int sanitize_region(const struct cxl_region *cxlr)
> */
> static int allocate_address_space(struct cxl_region *cxlr)
> {
> - /* TODO */
The problem with TODOs is now I forget which context calls
allocate_address_space(). If the caller was added in this patch it
would be reviewable, as is, I need to go to another window to search
"allocate_address_space" to recall that it is called from
cxl_region_probe(). That's too late as someone defining a region
should know upfront a region creation time that space has been
reserved, or not.
> - return 0;
> + struct cxl_decoder *rootd = rootd_from_region(cxlr);
> + unsigned long start;
s/unsigned long/resource_size_t/?
> +
> + start = gen_pool_alloc(rootd->address_space, cxlr->config.size);
> + if (!start) {
> + dev_dbg(&cxlr->dev, "Couldn't allocate %lluM of address space",
> + cxlr->config.size >> 20);
> + return -ENOMEM;
> + }
> +
> + cxlr->res =
> + __request_region(&rootd->platform_res, start, cxlr->config.size,
> + dev_name(&cxlr->dev), IORESOURCE_MEM);
> + if (!cxlr->res) {
> + dev_dbg(&cxlr->dev, "Couldn't obtain region from %s (%pR)\n",
> + dev_name(&rootd->dev), &rootd->platform_res);
> + gen_pool_free(rootd->address_space, start, cxlr->config.size);
> + return -ENOMEM;
> + }
> +
> + dev_dbg(&cxlr->dev, "resource %pR", cxlr->res);
> +
> + return devm_add_action_or_reset(&cxlr->dev, release_cxl_region, cxlr);
> }
>
> /**
> --
> 2.35.0
>
next prev parent reply other threads:[~2022-02-18 19:51 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-28 0:26 [PATCH v3 00/14] CXL Region driver Ben Widawsky
2022-01-28 0:26 ` [PATCH v3 01/14] cxl/region: Add region creation ABI Ben Widawsky
2022-01-28 18:14 ` Dan Williams
2022-01-28 18:59 ` Dan Williams
2022-02-02 18:26 ` Ben Widawsky
2022-02-02 18:28 ` Ben Widawsky
2022-02-02 18:48 ` Ben Widawsky
2022-02-02 19:00 ` Dan Williams
2022-02-02 19:02 ` Ben Widawsky
2022-02-02 19:15 ` Dan Williams
2022-02-01 22:42 ` Ben Widawsky
2022-02-01 15:53 ` Jonathan Cameron
2022-02-17 17:10 ` [PATCH v4 " Ben Widawsky
2022-02-17 17:19 ` [PATCH v5 01/15] " Ben Widawsky
2022-02-17 17:33 ` Ben Widawsky
2022-02-17 17:58 ` Dan Williams
2022-02-17 18:58 ` Ben Widawsky
2022-02-17 20:26 ` Dan Williams
2022-02-17 22:22 ` Ben Widawsky
2022-02-17 23:32 ` Dan Williams
2022-02-18 16:41 ` Ben Widawsky
2022-01-28 0:26 ` [PATCH v3 02/14] cxl/region: Introduce concept of region configuration Ben Widawsky
2022-01-29 0:25 ` Dan Williams
2022-02-01 14:59 ` Ben Widawsky
2022-02-03 5:06 ` Dan Williams
2022-02-01 23:11 ` Ben Widawsky
2022-02-03 17:48 ` Dan Williams
2022-02-03 22:23 ` Ben Widawsky
2022-02-03 23:27 ` Dan Williams
2022-02-04 0:19 ` Ben Widawsky
2022-02-04 2:45 ` Dan Williams
2022-02-17 18:36 ` Ben Widawsky
2022-02-17 19:57 ` Dan Williams
2022-02-17 20:20 ` Ben Widawsky
2022-02-17 21:12 ` Dan Williams
2022-02-23 21:49 ` Ben Widawsky
2022-02-23 22:24 ` Dan Williams
2022-02-23 22:31 ` Ben Widawsky
2022-02-23 22:42 ` Dan Williams
2022-01-28 0:26 ` [PATCH v3 03/14] cxl/mem: Cache port created by the mem dev Ben Widawsky
2022-02-17 1:20 ` Dan Williams
2022-01-28 0:26 ` [PATCH v3 04/14] cxl/region: Introduce a cxl_region driver Ben Widawsky
2022-02-01 16:21 ` Jonathan Cameron
2022-02-17 6:04 ` Dan Williams
2022-01-28 0:26 ` [PATCH v3 05/14] cxl/acpi: Handle address space allocation Ben Widawsky
2022-02-18 19:17 ` Dan Williams
2022-01-28 0:26 ` [PATCH v3 06/14] cxl/region: Address " Ben Widawsky
2022-02-18 19:51 ` Dan Williams [this message]
2022-01-28 0:27 ` [PATCH v3 07/14] cxl/region: Implement XHB verification Ben Widawsky
2022-02-18 20:23 ` Dan Williams
2022-01-28 0:27 ` [PATCH v3 08/14] cxl/region: HB port config verification Ben Widawsky
2022-02-14 16:20 ` Jonathan Cameron
2022-02-14 17:51 ` Ben Widawsky
2022-02-14 18:09 ` Jonathan Cameron
2022-02-15 16:35 ` Jonathan Cameron
2022-02-18 21:04 ` Dan Williams
2022-01-28 0:27 ` [PATCH v3 09/14] cxl/region: Add infrastructure for decoder programming Ben Widawsky
2022-02-01 18:16 ` Jonathan Cameron
2022-02-18 21:53 ` Dan Williams
2022-01-28 0:27 ` [PATCH v3 10/14] cxl/region: Collect host bridge decoders Ben Widawsky
2022-02-01 18:21 ` Jonathan Cameron
2022-02-18 23:42 ` Dan Williams
2022-01-28 0:27 ` [PATCH v3 11/14] cxl/region: Add support for single switch level Ben Widawsky
2022-02-01 18:26 ` Jonathan Cameron
2022-02-15 16:10 ` Jonathan Cameron
2022-02-18 18:23 ` Jonathan Cameron
2022-01-28 0:27 ` [PATCH v3 12/14] cxl: Program decoders for regions Ben Widawsky
2022-02-24 0:08 ` Dan Williams
2022-01-28 0:27 ` [PATCH v3 13/14] cxl/pmem: Convert nvdimm bridge API to use dev Ben Widawsky
2022-01-28 0:27 ` [PATCH v3 14/14] cxl/region: Create an nd_region Ben Widawsky
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