From: Ian Jackson <ian.jackson@citrix.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Anthony Perard <anthony.perard@citrix.com>,
Xen-devel <xen-devel@lists.xenproject.org>, Wei Liu <wl@xen.org>
Subject: Re: [Xen-devel] [PATCH 5/6] tools/libx[cl]: Don't use HVM_PARAM_PAE_ENABLED as a function parameter
Date: Tue, 11 Feb 2020 17:47:15 +0000 [thread overview]
Message-ID: <24130.59555.850210.126017@mariner.uk.xensource.com> (raw)
In-Reply-To: <20200205165056.11734-6-andrew.cooper3@citrix.com>
Andrew Cooper writes ("[PATCH 5/6] tools/libx[cl]: Don't use HVM_PARAM_PAE_ENABLED as a function parameter"):
> The sole use of HVM_PARAM_PAE_ENABLED is as a non-standard calling convention
> for xc_cpuid_apply_policy(). Pass PAE as a regular parameter instead.
>
> Leave a rather better explaination of why only HVM guests have a choice in PAE
> setting.
I am inclined believe you that this is right (since you are evidently
familiar with this whole area and I'm not), but the explanations leave
me confused.
> int xc_cpuid_apply_policy(xc_interface *xch, uint32_t domid,
> - const uint32_t *featureset, unsigned int nr_features)
> + const uint32_t *featureset, unsigned int nr_features,
> + bool pae)
> {
> int rc;
> xc_dominfo_t di;
> @@ -579,8 +580,6 @@ int xc_cpuid_apply_policy(xc_interface *xch, uint32_t domid,
> }
> else
> {
> - uint64_t val;
> -
> /*
> * Topology for HVM guests is entirely controlled by Xen. For now, we
> * hardcode APIC_ID = vcpu_id * 2 to give the illusion of no SMT.
> @@ -635,14 +634,10 @@ int xc_cpuid_apply_policy(xc_interface *xch, uint32_t domid,
> }
>
> /*
> - * HVM_PARAM_PAE_ENABLED is a parameter to this function, stashed in
> - * Xen. Nothing else has ever taken notice of the value.
> + * PAE used to be a parameter passed to this function by
> + * HVM_PARAM_PAE_ENABLED. It is now passed normally.
In particular, I don't understand what these comments mean by
"HVM_PARAM_PAE_ENABLED is a parameter to this function" and "PAE used
to be a parameter passed to this function by HVM_PARAM_PAE_ENABLED".
Maybe this is some loose use of the term "parameter" ?
If you could explain more clearly (ideally, explain the meaning of the
old comment in the commit message, and make the new comment
unambiguous) then that would be great.
Thanks,
Ian.
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel
next prev parent reply other threads:[~2020-02-11 17:47 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-05 16:50 [Xen-devel] [PATCH 0/6] tools: Rationalise legacy CPUID handling Andrew Cooper
2020-02-05 16:50 ` [Xen-devel] [PATCH 1/6] tools/libxl: Remove libxl_cpuid_{set, apply_policy}() from the API Andrew Cooper
2020-02-11 17:40 ` Ian Jackson
2020-02-05 16:50 ` [Xen-devel] [PATCH 2/6] tools/ocaml: Drop cpuid helpers Andrew Cooper
2020-02-06 14:25 ` Christian Lindig
2020-02-05 16:50 ` [Xen-devel] [PATCH 3/6] tools/python: " Andrew Cooper
2020-02-05 19:37 ` Marek Marczykowski-Górecki
2020-02-11 17:41 ` Ian Jackson
2020-02-05 16:50 ` [Xen-devel] [PATCH 4/6] tools/libxl: Combine legacy CPUID handling logic Andrew Cooper
2020-02-11 17:43 ` Ian Jackson
2020-02-05 16:50 ` [Xen-devel] [PATCH 5/6] tools/libx[cl]: Don't use HVM_PARAM_PAE_ENABLED as a function parameter Andrew Cooper
2020-02-11 17:47 ` Ian Jackson [this message]
2020-02-11 17:55 ` Andrew Cooper
2020-02-17 15:40 ` Ian Jackson
2020-02-17 17:57 ` [Xen-devel] [PATCH v2 " Andrew Cooper
2020-02-17 17:59 ` Ian Jackson
2020-02-05 16:50 ` [Xen-devel] [PATCH 6/6] xen/public: Obsolete HVM_PARAM_PAE_ENABLED Andrew Cooper
2020-02-06 9:28 ` Jan Beulich
2020-02-06 11:32 ` Andrew Cooper
2020-02-06 11:37 ` Jan Beulich
2020-02-06 12:25 ` Andrew Cooper
2020-02-08 12:12 ` Julien Grall
2020-02-08 12:15 ` Andrew Cooper
2020-02-11 17:49 ` Ian Jackson
2020-02-11 18:03 ` Andrew Cooper
Reply instructions:
You may reply publicly 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=24130.59555.850210.126017@mariner.uk.xensource.com \
--to=ian.jackson@citrix.com \
--cc=andrew.cooper3@citrix.com \
--cc=anthony.perard@citrix.com \
--cc=wl@xen.org \
--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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).