From: Julien Grall <julien.grall@arm.com>
To: Andrii Anisov <andrii.anisov@gmail.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: "Oleksandr_Tyshchenko@epam.com" <Oleksandr_Tyshchenko@epam.com>,
nd <nd@arm.com>,
"Andrii_Anisov@epam.com" <Andrii_Anisov@epam.com>,
"sstabellini@kernel.org" <sstabellini@kernel.org>
Subject: Re: [PATCH 2/7] xen/arm: Remove flush_xen_text_tlb_local()
Date: Fri, 26 Apr 2019 15:31:11 +0100 [thread overview]
Message-ID: <7c231a06-bac3-1a76-2fc8-73042a900953@arm.com> (raw)
In-Reply-To: <eb656a28-7910-c65a-bf50-1c62494f5acd@gmail.com>
On 26/04/2019 15:15, Andrii Anisov wrote:
> Julien,
>
> Sorry, reply format is broken. It should be as following:
>
> On 26.04.19 16:50, Andrii Anisov wrote:
>>> To be honest, I am not entirely sure whether the isb() is necessary
>>> here. At worst, an entry of an existing mappings is not cached with the
>>> SCTLR_EL2.WXN set. This may only defer the problem is an entry is
>>> incorrectly configured before the flush. This is done early at boot (and
>>> will be done much earlier in [1]).
>
>
> Well, following this logic we may finish with TLB flush is not needed here at
> all. Because entries, already reached TLB, were configured before, and are
> believed valid. All the next will have WXN set.
> But in this case, ISB is needed as an exact point from which all new TLB entries
> will have WXN.
I am not sure to follow your point here. It wasn't clear to me whether the isb()
between setting SCTLR_EL2.WXN and TLB flush is strictly necessary. The TLB flush
contain an isb() so, it may has well be enough here.
However, speaking with Mark Rutland, it would be best to keep the sequence
suggest in this patch. So SCTLR_EL2.WXN is visible before the flush and the
flush will ensure all current entries are removed. So none of the entries should
have WXN cleared.
So I will keep this patch as is.
Cheers,
--
Julien Grall
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel
WARNING: multiple messages have this Message-ID (diff)
From: Julien Grall <julien.grall@arm.com>
To: Andrii Anisov <andrii.anisov@gmail.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: "Oleksandr_Tyshchenko@epam.com" <Oleksandr_Tyshchenko@epam.com>,
nd <nd@arm.com>,
"Andrii_Anisov@epam.com" <Andrii_Anisov@epam.com>,
"sstabellini@kernel.org" <sstabellini@kernel.org>
Subject: Re: [Xen-devel] [PATCH 2/7] xen/arm: Remove flush_xen_text_tlb_local()
Date: Fri, 26 Apr 2019 15:31:11 +0100 [thread overview]
Message-ID: <7c231a06-bac3-1a76-2fc8-73042a900953@arm.com> (raw)
Message-ID: <20190426143111.meMnMMnecDccubheR6cc2_waO5RYZlAK7qpKluyRI00@z> (raw)
In-Reply-To: <eb656a28-7910-c65a-bf50-1c62494f5acd@gmail.com>
On 26/04/2019 15:15, Andrii Anisov wrote:
> Julien,
>
> Sorry, reply format is broken. It should be as following:
>
> On 26.04.19 16:50, Andrii Anisov wrote:
>>> To be honest, I am not entirely sure whether the isb() is necessary
>>> here. At worst, an entry of an existing mappings is not cached with the
>>> SCTLR_EL2.WXN set. This may only defer the problem is an entry is
>>> incorrectly configured before the flush. This is done early at boot (and
>>> will be done much earlier in [1]).
>
>
> Well, following this logic we may finish with TLB flush is not needed here at
> all. Because entries, already reached TLB, were configured before, and are
> believed valid. All the next will have WXN set.
> But in this case, ISB is needed as an exact point from which all new TLB entries
> will have WXN.
I am not sure to follow your point here. It wasn't clear to me whether the isb()
between setting SCTLR_EL2.WXN and TLB flush is strictly necessary. The TLB flush
contain an isb() so, it may has well be enough here.
However, speaking with Mark Rutland, it would be best to keep the sequence
suggest in this patch. So SCTLR_EL2.WXN is visible before the flush and the
flush will ensure all current entries are removed. So none of the entries should
have WXN cleared.
So I will keep this patch as is.
Cheers,
--
Julien Grall
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel
next prev parent reply other threads:[~2019-04-26 14:31 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-17 17:58 [PATCH 0/7] xen/arm: TLB flush helpers rework Julien Grall
2019-04-17 17:58 ` [Xen-devel] " Julien Grall
2019-04-17 17:58 ` [PATCH 1/7] xen/arm: mm: Consolidate setting SCTLR_EL2.WXN in a single place Julien Grall
2019-04-17 17:58 ` [Xen-devel] " Julien Grall
2019-04-25 18:00 ` Andrii Anisov
2019-04-25 18:00 ` [Xen-devel] " Andrii Anisov
2019-04-25 20:26 ` Julien Grall
2019-04-25 20:26 ` [Xen-devel] " Julien Grall
2019-04-26 13:48 ` Andrii Anisov
2019-04-26 13:48 ` [Xen-devel] " Andrii Anisov
2019-04-17 17:58 ` [PATCH 2/7] xen/arm: Remove flush_xen_text_tlb_local() Julien Grall
2019-04-17 17:58 ` [Xen-devel] " Julien Grall
2019-04-25 18:00 ` Andrii Anisov
2019-04-25 18:00 ` [Xen-devel] " Andrii Anisov
2019-04-25 20:37 ` Julien Grall
2019-04-25 20:37 ` [Xen-devel] " Julien Grall
2019-04-26 13:50 ` Andrii Anisov
2019-04-26 13:50 ` [Xen-devel] " Andrii Anisov
2019-04-26 14:15 ` Andrii Anisov
2019-04-26 14:15 ` [Xen-devel] " Andrii Anisov
2019-04-26 14:31 ` Julien Grall [this message]
2019-04-26 14:31 ` Julien Grall
2019-04-26 15:08 ` Andrii Anisov
2019-04-26 15:08 ` [Xen-devel] " Andrii Anisov
2019-04-17 17:58 ` [PATCH 3/7] xen/arm: tlbflush: Clarify the TLB helpers name Julien Grall
2019-04-17 17:58 ` [Xen-devel] " Julien Grall
2019-04-25 18:00 ` Andrii Anisov
2019-04-25 18:00 ` [Xen-devel] " Andrii Anisov
2019-04-17 17:58 ` [PATCH 4/7] xen/arm: page: Clarify the Xen TLBs " Julien Grall
2019-04-17 17:58 ` [Xen-devel] " Julien Grall
2019-04-25 18:00 ` Andrii Anisov
2019-04-25 18:00 ` [Xen-devel] " Andrii Anisov
2019-04-17 17:58 ` [PATCH 5/7] xen/arm: Gather all TLB flush helpers in tlbflush.h Julien Grall
2019-04-17 17:58 ` [Xen-devel] " Julien Grall
2019-04-25 18:01 ` Andrii Anisov
2019-04-25 18:01 ` [Xen-devel] " Andrii Anisov
2019-04-17 17:58 ` [PATCH 6/7] xen/arm: tlbflush: Rework TLB helpers Julien Grall
2019-04-17 17:58 ` [Xen-devel] " Julien Grall
2019-04-25 18:01 ` Andrii Anisov
2019-04-25 18:01 ` [Xen-devel] " Andrii Anisov
2019-04-25 20:42 ` Julien Grall
2019-04-25 20:42 ` [Xen-devel] " Julien Grall
2019-04-26 13:49 ` Andrii Anisov
2019-04-26 13:49 ` [Xen-devel] " Andrii Anisov
2019-04-26 14:06 ` Julien Grall
2019-04-26 14:06 ` [Xen-devel] " Julien Grall
2019-04-26 15:17 ` Andrii Anisov
2019-04-26 15:17 ` [Xen-devel] " Andrii Anisov
2019-04-17 17:58 ` [PATCH 7/7] xen/arm: mm: Flush the TLBs even if a mapping failed in create_xen_entries Julien Grall
2019-04-17 17:58 ` [Xen-devel] " Julien Grall
2019-04-25 18:03 ` Andrii Anisov
2019-04-25 18:03 ` [Xen-devel] " Andrii Anisov
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=7c231a06-bac3-1a76-2fc8-73042a900953@arm.com \
--to=julien.grall@arm.com \
--cc=Andrii_Anisov@epam.com \
--cc=Oleksandr_Tyshchenko@epam.com \
--cc=andrii.anisov@gmail.com \
--cc=nd@arm.com \
--cc=sstabellini@kernel.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.