When CONFIG_DMA_DIRECT_REMAP is enabled, atomic pool pages are
remapped via dma_common_contiguous_remap() using the supplied
pgprot. Currently, the mapping uses
pgprot_dmacoherent(PAGE_KERNEL), which leaves the memory encrypted
on systems with memory encryption enabled (e.g., ARM CCA Realms).
This can cause the DMA layer to fail or crash when accessing the
memory, as the underlying physical pages are not configured as
expected.
Fix this by requesting a decrypted mapping in the vmap() call:
pgprot_decrypted(pgprot_dmacoherent(PAGE_KERNEL))
This ensures that atomic pool memory is consistently mapped
unencrypted.
Cc: stable(a)vger.kernel.org
Signed-off-by: Shanker Donthineni <sdonthineni(a)nvidia.com>
---
kernel/dma/pool.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
index 7b04f7575796b..ee45dee33d491 100644
--- a/kernel/dma/pool.c
+++ b/kernel/dma/pool.c
@@ -102,8 +102,8 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
#ifdef CONFIG_DMA_DIRECT_REMAP
addr = dma_common_contiguous_remap(page, pool_size,
- pgprot_dmacoherent(PAGE_KERNEL),
- __builtin_return_address(0));
+ pgprot_decrypted(pgprot_dmacoherent(PAGE_KERNEL)),
+ __builtin_return_address(0));
if (!addr)
goto free_page;
#else
--
2.25.1
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On Tue, 12 Aug 2025 15:28:58 +0200 Przemek Kitszel wrote:
> Summary:
> Split ice_virtchnl.c into two more files (+headers), in a way
> that git-blame works better.
> Then move virtchnl files into a new subdir.
> No logic changes.
>
> I have developed (or discovered ;)) how to split a file in a way that
> both old and new are nice in terms of git-blame
> There were no much disscussion on [RFC], so I would like to propose
> to go forward with this approach.
>
> There is more commits needed to have it nice, so it forms a git-log vs
> git-blame tradeoff, but (after the brief moment that this is on the top)
> we spend orders of magnitude more time looking at the blame output (and
> commit messages linked from that) - so I find it much better to see
> actual logic changes instead of "move xx to yy" stuff (typical for
> "squashed/single-commit splits").
>
> Cherry-picks/rebases work the same with this method as with simple
> "squashed/single-commit" approach (literally all commits squashed into
> one (to have better git-log, but shitty git-blame output).
>
> Rationale for the split itself is, as usual, "file is big and we want to
> extend it".
>
> This series is available on my github (just rebased from any
> earlier mentions):
> https://github.com/pkitszel/linux/tree/virtchnl-split-Aug12
> (the simple git-email view flattens this series, removing two
> merges from the view).
>
>
> [RFC]:
> https://lore.kernel.org/netdev/5b94d14e-a0e7-47bd-82fc-c85171cbf26e@intel.c…
>
> (I would really look at my fork via your preferred git interaction tool
> instead of looking at the patches below).
UI tools aside I wish you didn't cut off the diffstat from the cover
letter :/ It'd make it much easier to understand what you're splitting.
Greg, Sasha, I suspect stable will suffer the most from any file split /
movement. Do you have any recommendation on what should be allowed?
The patch titled
Subject: iov_iter: iterate_folioq: fix handling of offset >= folio size
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
iov_iter-iterate_folioq-fix-handling-of-offset-=-folio-size.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche…
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Dominique Martinet <asmadeus(a)codewreck.org>
Subject: iov_iter: iterate_folioq: fix handling of offset >= folio size
Date: Mon, 11 Aug 2025 16:39:05 +0900
So we've had this regression in 9p for.. almost a year, which is way too
long, but there was no "easy" reproducer until yesterday (thank you
again!!)
It turned out to be a bug with iov_iter on folios,
iov_iter_get_pages_alloc2() would advance the iov_iter correctly up to the
end edge of a folio and the later copy_to_iter() fails on the
iterate_folioq() bug.
Happy to consider alternative ways of fixing this, now there's a
reproducer it's all much clearer; for the bug to be visible we basically
need to make and IO with non-contiguous folios in the iov_iter which is
not obvious to test with synthetic VMs, with size that triggers a
zero-copy read followed by a non-zero-copy read.
It's apparently possible to get an iov forwarded all the way up to the end
of the current page we're looking at, e.g.
(gdb) p *iter
$24 = {iter_type = 4 '\004', nofault = false, data_source = false, iov_offset = 4096, {__ubuf_iovec = {
iov_base = 0xffff88800f5bc000, iov_len = 655}, {{__iov = 0xffff88800f5bc000, kvec = 0xffff88800f5bc000,
bvec = 0xffff88800f5bc000, folioq = 0xffff88800f5bc000, xarray = 0xffff88800f5bc000,
ubuf = 0xffff88800f5bc000}, count = 655}}, {nr_segs = 2, folioq_slot = 2 '\002', xarray_start = 2}}
Where iov_offset is 4k with 4k-sized folios
This should have been because we're only in the 2nd slot and there's
another one after this, but iterate_folioq should not try to map a folio
that skips the whole size, and more importantly part here does not end up
zero (because 'PAGE_SIZE - skip % PAGE_SIZE' ends up PAGE_SIZE and not
zero..), so skip forward to the "advance to next folio" code.
Link: https://lkml.kernel.org/r/20250811-iot_iter_folio-v1-0-d9c223adf93c@codewre…
Link: https://lkml.kernel.org/r/20250811-iot_iter_folio-v1-1-d9c223adf93c@codewre…
Link: https://lkml.kernel.org/r/D4LHHUNLG79Y.12PI0X6BEHRHW@mbosch.me/
Fixes: db0aa2e9566f ("mm: Define struct folio_queue and ITER_FOLIOQ to handle a sequence of folios")
Signed-off-by: Dominique Martinet <asmadeus(a)codewreck.org>
Reported-by: Maximilian Bosch <maximilian(a)mbosch.me>
Reported-by: Ryan Lahfa <ryan(a)lahfa.xyz>
Reported-by: Christian Theune <ct(a)flyingcircus.io>
Reported-by: Arnout Engelen <arnout(a)bzzt.net>
Cc: Al Viro <viro(a)zeniv.linux.org.uk>
Cc: Christian Brauner <brauner(a)kernel.org>
Cc: David Howells <dhowells(a)redhat.com>
Cc: Ryan Lahfa <ryan(a)lahfa.xyz>
Cc: <stable(a)vger.kernel.org> [v6.12+]
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
include/linux/iov_iter.h | 3 +++
1 file changed, 3 insertions(+)
--- a/include/linux/iov_iter.h~iov_iter-iterate_folioq-fix-handling-of-offset-=-folio-size
+++ a/include/linux/iov_iter.h
@@ -168,6 +168,8 @@ size_t iterate_folioq(struct iov_iter *i
break;
fsize = folioq_folio_size(folioq, slot);
+ if (skip >= fsize)
+ goto next;
base = kmap_local_folio(folio, skip);
part = umin(len, PAGE_SIZE - skip % PAGE_SIZE);
remain = step(base, progress, part, priv, priv2);
@@ -177,6 +179,7 @@ size_t iterate_folioq(struct iov_iter *i
progress += consumed;
skip += consumed;
if (skip >= fsize) {
+next:
skip = 0;
slot++;
if (slot == folioq_nr_slots(folioq) && folioq->next) {
_
Patches currently in -mm which might be from asmadeus(a)codewreck.org are
iov_iter-iterate_folioq-fix-handling-of-offset-=-folio-size.patch
iov_iter-iov_folioq_get_pages-dont-leave-empty-slot-behind.patch