Xen-Devel Archive on lore.kernel.org
 help / color / Atom feed
From: Stefano Stabellini <sstabellini@kernel.org>
To: Julien Grall <julien.grall@arm.com>
Cc: xen-devel@lists.xenproject.org,
	Stefano Stabellini <sstabellini@kernel.org>,
	Stefano Stabellini <stefanos@xilinx.com>
Subject: Re: [Xen-devel] [PATCH v2 08/10] xen/arm: keep track of reserved-memory regions
Date: Fri, 21 Jun 2019 16:47:46 -0700 (PDT)
Message-ID: <alpine.DEB.2.21.1906211532220.25730@sstabellini-ThinkPad-T480s> (raw)
In-Reply-To: <a897193b-8dd2-2874-ea62-c9f404d14936@arm.com>

On Wed, 1 May 2019, Julien Grall wrote:
> Hi Stefano,
> 
> On 30/04/2019 22:02, Stefano Stabellini wrote:
> > As we parse the device tree in Xen, keep track of the reserved-memory
> > regions as they need special treatment (follow-up patches will make use
> > of the stored information.)
> > 
> > Reuse process_memory_node to add reserved-memory regions to the
> > bootinfo.reserved_mem array. Remove the warning if there is no reg in
> > process_memory_node because it is a normal condition for
> > reserved-memory.
> 
> And it is not a normal condition for /memory... So your argument here is not
> sufficient for me to not keep the warning here for /memory.
 
You are right, I'll put the warning back in place.


> Rather than trying to re-purpose process_memory_node, I would prefer if you
> move out the parsing of "reg" and then provide 2 functions (one for /memory
> and one for /reserved-memory).
> 
> The parsing function will return an error if "reg" is not present, but it can
> be ignored by /reserved-memory and a warning is added for /memory.

I am OK with making this change, but I gave a look at the code for some
time and I cannot exactly figure out the interface you have in mind. I
understand completely separating the functions as I did in v1, but not
the partial split you are suggesting here.

I managed to address your other comments keeping a single function. I
suggest you take a look at the new version, then maybe write some
psedo-code to help me figure out what you would like me to do?


> > 
> > Signed-off-by: Stefano Stabellini <stefanos@xilinx.com>
> > 
> > ---
> > 
> > Not done: create an e820-like structure on ARM.
> > 
> > Changes in v2:
> > - call process_memory_node from process_reserved_memory_node to avoid
> >    duplication
> > ---
> >   xen/arch/arm/bootfdt.c      | 30 ++++++++++++++++++++++--------
> >   xen/include/asm-arm/setup.h |  1 +
> >   2 files changed, 23 insertions(+), 8 deletions(-)
> > 
> > diff --git a/xen/arch/arm/bootfdt.c b/xen/arch/arm/bootfdt.c
> > index b6600ab..9355a6e 100644
> > --- a/xen/arch/arm/bootfdt.c
> > +++ b/xen/arch/arm/bootfdt.c
> > @@ -135,6 +135,8 @@ static int __init process_memory_node(const void *fdt,
> > int node,
> >       const __be32 *cell;
> >       paddr_t start, size;
> >       u32 reg_cells = address_cells + size_cells;
> > +    struct meminfo *mem;
> > +    bool reserved = (bool)data;
> >         if ( address_cells < 1 || size_cells < 1 )
> >       {
> > @@ -143,29 +145,39 @@ static int __init process_memory_node(const void *fdt,
> > int node,
> >           return 0;
> >       }
> >   +    if ( reserved )
> > +        mem = &bootinfo.reserved_mem;
> > +    else
> > +        mem = &bootinfo.mem;
> > +
> >       prop = fdt_get_property(fdt, node, "reg", NULL);
> >       if ( !prop )
> > -    {
> > -        printk("fdt: node `%s': missing `reg' property\n", name);
> >           return 0;
> > -    }
> >         cell = (const __be32 *)prop->data;
> >       banks = fdt32_to_cpu(prop->len) / (reg_cells * sizeof (u32));
> >   -    for ( i = 0; i < banks && bootinfo.mem.nr_banks < NR_MEM_BANKS; i++ )
> > +    for ( i = 0; i < banks && mem->nr_banks < NR_MEM_BANKS; i++ )
> 
> As I pointed out on v1, this is pretty fragile. While ignoring /memory bank is
> fine if we have no more space, for /reserved-region this may mean using them
> in Xen allocator with the consequences we all know.

Yeah, we don't want that.


> If you split the function properly, then you will be able to treat
> reserved-regions and memory differently.

I did so, but without splitting the functions.

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

  parent reply index

Thread overview: 86+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-30 21:02 [PATCH v2 0/10] iomem memory policy Stefano Stabellini
2019-04-30 21:02 ` [Xen-devel] " Stefano Stabellini
2019-04-30 21:02 ` [PATCH v2 01/10] xen: add a p2mt parameter to map_mmio_regions Stefano Stabellini
2019-04-30 21:02   ` [Xen-devel] " Stefano Stabellini
2019-05-02 14:59   ` Jan Beulich
2019-05-02 14:59     ` [Xen-devel] " Jan Beulich
2019-05-02 18:49     ` Stefano Stabellini
2019-05-02 18:49       ` [Xen-devel] " Stefano Stabellini
2019-05-15 13:39   ` Oleksandr
2019-05-15 13:39     ` [Xen-devel] " Oleksandr
2019-04-30 21:02 ` [PATCH v2 02/10] xen: rename un/map_mmio_regions to un/map_regions Stefano Stabellini
2019-04-30 21:02   ` [Xen-devel] " Stefano Stabellini
2019-05-01  9:22   ` Julien Grall
2019-05-01  9:22     ` [Xen-devel] " Julien Grall
2019-06-17 21:24     ` Stefano Stabellini
2019-06-18 11:05       ` Julien Grall
2019-06-18 20:19         ` Stefano Stabellini
2019-05-02 15:03   ` Jan Beulich
2019-05-02 15:03     ` [Xen-devel] " Jan Beulich
2019-05-02 18:55     ` Stefano Stabellini
2019-05-02 18:55       ` [Xen-devel] " Stefano Stabellini
2019-04-30 21:02 ` [PATCH v2 03/10] xen: extend XEN_DOMCTL_memory_mapping to handle memory policy Stefano Stabellini
2019-04-30 21:02   ` [Xen-devel] " Stefano Stabellini
2019-05-02 15:12   ` Jan Beulich
2019-05-02 15:12     ` [Xen-devel] " Jan Beulich
2019-06-17 21:28     ` Stefano Stabellini
2019-06-18  8:59       ` Jan Beulich
2019-06-18 20:32         ` Stefano Stabellini
2019-06-18 23:15           ` Stefano Stabellini
2019-06-19  6:53             ` Jan Beulich
2019-05-07 16:41   ` Julien Grall
2019-05-07 16:41     ` [Xen-devel] " Julien Grall
2019-06-17 22:43     ` Stefano Stabellini
2019-06-18 11:13       ` Julien Grall
2019-05-15 14:40   ` Oleksandr
2019-05-15 14:40     ` [Xen-devel] " Oleksandr
2019-04-30 21:02 ` [PATCH v2 04/10] libxc: introduce xc_domain_mem_map_policy Stefano Stabellini
2019-04-30 21:02   ` [Xen-devel] " Stefano Stabellini
2019-04-30 21:02 ` [PATCH v2 05/10] libxl/xl: add memory policy option to iomem Stefano Stabellini
2019-04-30 21:02   ` [Xen-devel] " Stefano Stabellini
2019-05-01  9:42   ` Julien Grall
2019-05-01  9:42     ` [Xen-devel] " Julien Grall
2019-06-17 22:32     ` Stefano Stabellini
2019-06-18 11:09       ` Julien Grall
2019-06-18 11:15   ` Julien Grall
2019-06-18 22:07     ` Stefano Stabellini
2019-06-18 22:20       ` Julien Grall
2019-06-18 22:46         ` Stefano Stabellini
2019-04-30 21:02 ` [PATCH v2 06/10] xen/arm: extend device_tree_for_each_node Stefano Stabellini
2019-04-30 21:02   ` [Xen-devel] " Stefano Stabellini
2019-05-07 17:12   ` Julien Grall
2019-05-07 17:12     ` [Xen-devel] " Julien Grall
2019-04-30 21:02 ` [PATCH v2 07/10] xen/arm: make process_memory_node a device_tree_node_func Stefano Stabellini
2019-04-30 21:02   ` [Xen-devel] " Stefano Stabellini
2019-05-01  9:47   ` Julien Grall
2019-05-01  9:47     ` [Xen-devel] " Julien Grall
2019-04-30 21:02 ` [PATCH v2 08/10] xen/arm: keep track of reserved-memory regions Stefano Stabellini
2019-04-30 21:02   ` [Xen-devel] " Stefano Stabellini
2019-05-01 10:03   ` Julien Grall
2019-05-01 10:03     ` [Xen-devel] " Julien Grall
2019-06-21 23:47     ` Stefano Stabellini [this message]
2019-05-07 17:21   ` Julien Grall
2019-05-07 17:21     ` [Xen-devel] " Julien Grall
2019-04-30 21:02 ` [PATCH v2 09/10] xen/arm: map reserved-memory regions as normal memory in dom0 Stefano Stabellini
2019-04-30 21:02   ` [Xen-devel] " Stefano Stabellini
2019-05-07 19:52   ` Julien Grall
2019-05-07 19:52     ` [Xen-devel] " Julien Grall
2019-04-30 21:02 ` [PATCH v2 10/10] xen/arm: add reserved-memory regions to the dom0 memory node Stefano Stabellini
2019-04-30 21:02   ` [Xen-devel] " Stefano Stabellini
2019-05-07 20:15   ` Julien Grall
2019-05-07 20:15     ` [Xen-devel] " Julien Grall
2019-05-10 20:51     ` Stefano Stabellini
2019-05-10 20:51       ` [Xen-devel] " Stefano Stabellini
2019-05-10 21:43       ` Julien Grall
2019-05-10 21:43         ` [Xen-devel] " Julien Grall
2019-05-11 12:40         ` Julien Grall
2019-05-11 12:40           ` [Xen-devel] " Julien Grall
2019-05-20 21:26           ` Stefano Stabellini
2019-05-20 21:26             ` [Xen-devel] " Stefano Stabellini
2019-05-20 22:38             ` Julien Grall
2019-05-20 22:38               ` [Xen-devel] " Julien Grall
2019-06-05 16:30               ` Julien Grall
2019-06-21 23:47                 ` Stefano Stabellini
2019-05-16 16:52 ` [PATCH v2 0/10] iomem memory policy Oleksandr
2019-05-16 16:52   ` [Xen-devel] " Oleksandr
2019-06-21 23:48   ` Stefano Stabellini

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=alpine.DEB.2.21.1906211532220.25730@sstabellini-ThinkPad-T480s \
    --to=sstabellini@kernel.org \
    --cc=julien.grall@arm.com \
    --cc=stefanos@xilinx.com \
    --cc=xen-devel@lists.xenproject.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Xen-Devel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/xen-devel/0 xen-devel/git/0.git
	git clone --mirror https://lore.kernel.org/xen-devel/1 xen-devel/git/1.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 xen-devel xen-devel/ https://lore.kernel.org/xen-devel \
		xen-devel@lists.xenproject.org xen-devel@archiver.kernel.org
	public-inbox-index xen-devel


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.xenproject.lists.xen-devel


AGPL code for this site: git clone https://public-inbox.org/ public-inbox