<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/linux.git, branch v6.12.21</title>
<subtitle>Linux kernel stable tree (mirror)</subtitle>
<id>https://git.radix-linux.su/kernel/linux.git/atom?h=v6.12.21</id>
<link rel='self' href='https://git.radix-linux.su/kernel/linux.git/atom?h=v6.12.21'/>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/'/>
<updated>2025-03-28T21:03:33+00:00</updated>
<entry>
<title>Linux 6.12.21</title>
<updated>2025-03-28T21:03:33+00:00</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2025-03-28T21:03:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=3423cae6907838f760aada1a72bb6e378ebaa16d'/>
<id>urn:sha1:3423cae6907838f760aada1a72bb6e378ebaa16d</id>
<content type='text'>
Link: https://lore.kernel.org/r/20250325122149.207086105@linuxfoundation.org
Tested-by: Florian Fainelli &lt;florian.fainelli@broadcom.com&gt;
Tested-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
Tested-by: Pavel Machek (CIP) &lt;pavel@denx.de&gt;
Link: https://lore.kernel.org/r/20250326154546.724728617@linuxfoundation.org
Tested-by: Florian Fainelli &lt;florian.fainelli@broadcom.com&gt;
Tested-by: Hardik Garg &lt;hargar@linux.microsoft.com&gt;
Tested-by: Peter Schneider &lt;pschneider1968@googlemail.com&gt;
Tested-by: Ron Economos &lt;re@w6rz.net&gt;
Tested-by: Mark Brown &lt;broonie@kernel.org&gt;
Tested-by: Jon Hunter &lt;jonathanh@nvidia.com&gt;
Tested-by: Harshit Mogalapalli &lt;harshit.m.mogalapalli@oracle.com&gt;
Tested-by: Harshit Mogalapalli &amp;lt;harshit.m.mogalapalli@oracle.com&amp;gt;&lt;br&gt;
Tested-by: Harshit Mogalapalli &lt;harshit.m.mogalapalli@oracle.com&gt;
Tested-by: Linux Kernel Functional Testing &lt;lkft@linaro.org&gt;
Tested-by: Pavel Machek (CIP) &lt;pavel@denx.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mptcp: Fix data stream corruption in the address announcement</title>
<updated>2025-03-28T21:03:33+00:00</updated>
<author>
<name>Arthur Mongodin</name>
<email>amongodin@randorisec.fr</email>
</author>
<published>2025-03-14T20:11:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=2fa52cd829c194c86f3c324d2a49018393bf70d1'/>
<id>urn:sha1:2fa52cd829c194c86f3c324d2a49018393bf70d1</id>
<content type='text'>
commit 2c1f97a52cb827a5f2768e67a9dddffae1ed47ab upstream.

Because of the size restriction in the TCP options space, the MPTCP
ADD_ADDR option is exclusive and cannot be sent with other MPTCP ones.
For this reason, in the linked mptcp_out_options structure, group of
fields linked to different options are part of the same union.

There is a case where the mptcp_pm_add_addr_signal() function can modify
opts-&gt;addr, but not ended up sending an ADD_ADDR. Later on, back in
mptcp_established_options, other options will be sent, but with
unexpected data written in other fields due to the union, e.g. in
opts-&gt;ext_copy. This could lead to a data stream corruption in the next
packet.

Using an intermediate variable, prevents from corrupting previously
established DSS option. The assignment of the ADD_ADDR option
parameters is now done once we are sure this ADD_ADDR option can be set
in the packet, e.g. after having dropped other suboptions.

Fixes: 1bff1e43a30e ("mptcp: optimize out option generation")
Cc: stable@vger.kernel.org
Suggested-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Signed-off-by: Arthur Mongodin &lt;amongodin@randorisec.fr&gt;
Reviewed-by: Matthieu Baerts (NGI0) &lt;matttbe@kernel.org&gt;
[ Matt: the commit message has been updated: long lines splits and some
  clarifications. ]
Signed-off-by: Matthieu Baerts (NGI0) &lt;matttbe@kernel.org&gt;
Reviewed-by: Simon Horman &lt;horms@kernel.org&gt;
Link: https://patch.msgid.link/20250314-net-mptcp-fix-data-stream-corr-sockopt-v1-1-122dbb249db3@kernel.org
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>mm/huge_memory: drop beyond-EOF folios with the right number of refs</title>
<updated>2025-03-28T21:03:33+00:00</updated>
<author>
<name>Zi Yan</name>
<email>ziy@nvidia.com</email>
</author>
<published>2025-03-10T15:57:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=86368616a9ce51f6b41efa251b6e066893851d67'/>
<id>urn:sha1:86368616a9ce51f6b41efa251b6e066893851d67</id>
<content type='text'>
commit 14efb4793519d73fb2902bb0ece319b886e4b4b9 upstream.

When an after-split folio is large and needs to be dropped due to EOF,
folio_put_refs(folio, folio_nr_pages(folio)) should be used to drop all
page cache refs.  Otherwise, the folio will not be freed, causing memory
leak.

This leak would happen on a filesystem with blocksize &gt; page_size and a
truncate is performed, where the blocksize makes folios split to &gt;0 order
ones, causing truncated folios not being freed.

Link: https://lkml.kernel.org/r/20250310155727.472846-1-ziy@nvidia.com
Fixes: c010d47f107f ("mm: thp: split huge page to any lower order pages")
Signed-off-by: Zi Yan &lt;ziy@nvidia.com&gt;
Reported-by: Hugh Dickins &lt;hughd@google.com&gt;
Closes: https://lore.kernel.org/all/fcbadb7f-dd3e-21df-f9a7-2853b53183c4@google.com/
Cc: Baolin Wang &lt;baolin.wang@linux.alibaba.com&gt;
Cc: David Hildenbrand &lt;david@redhat.com&gt;
Cc: John Hubbard &lt;jhubbard@nvidia.com&gt;
Cc: Kefeng Wang &lt;wangkefeng.wang@huawei.com&gt;
Cc: Kirill A. Shuemov &lt;kirill.shutemov@linux.intel.com&gt;
Cc: Luis Chamberalin &lt;mcgrof@kernel.org&gt;
Cc: Matthew Wilcow (Oracle) &lt;willy@infradead.org&gt;
Cc: Miaohe Lin &lt;linmiaohe@huawei.com&gt;
Cc: Pankaj Raghav &lt;p.raghav@samsung.com&gt;
Cc: Ryan Roberts &lt;ryan.roberts@arm.com&gt;
Cc: Yang Shi &lt;yang@os.amperecomputing.com&gt;
Cc: Yu Zhao &lt;yuzhao@google.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>arm64: dts: rockchip: fix u2phy1_host status for NanoPi R4S</title>
<updated>2025-03-28T21:03:33+00:00</updated>
<author>
<name>Justin Klaassen</name>
<email>justin@tidylabs.net</email>
</author>
<published>2025-02-25T17:03:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=e7940c5794c3e936b5517b00c1668c6e0cc1bc09'/>
<id>urn:sha1:e7940c5794c3e936b5517b00c1668c6e0cc1bc09</id>
<content type='text'>
commit 38f4aa34a5f737ea8588dac320d884cc2e762c03 upstream.

The u2phy1_host should always have the same status as usb_host1_ehci
and usb_host1_ohci, otherwise the EHCI and OHCI drivers may be
initialized for a disabled usb port.

Per the NanoPi R4S schematic, the phy-supply for u2phy1_host is set to
the vdd_5v regulator.

Fixes: db792e9adbf8 ("rockchip: rk3399: Add support for FriendlyARM NanoPi R4S")
Cc: stable@vger.kernel.org
Signed-off-by: Justin Klaassen &lt;justin@tidylabs.net&gt;
Reviewed-by: Dragan Simic &lt;dsimic@manjaro.org&gt;
Link: https://lore.kernel.org/r/20250225170420.3898-1-justin@tidylabs.net
Signed-off-by: Heiko Stuebner &lt;heiko@sntech.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>libsubcmd: Silence compiler warning</title>
<updated>2025-03-28T21:03:33+00:00</updated>
<author>
<name>Eder Zulian</name>
<email>ezulian@redhat.com</email>
</author>
<published>2024-10-22T17:23:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=9aaffd3718293523727e650b292963df3e1c1be0'/>
<id>urn:sha1:9aaffd3718293523727e650b292963df3e1c1be0</id>
<content type='text'>
commit 7a4ffec9fd54ea27395e24dff726dbf58e2fe06b upstream.

Initialize the pointer 'o' in options__order to NULL to prevent a
compiler warning/error which is observed when compiling with the '-Og'
option, but is not emitted by the compiler with the current default
compilation options.

For example, when compiling libsubcmd with

 $ make "EXTRA_CFLAGS=-Og" -C tools/lib/subcmd/ clean all

Clang version 17.0.6 and GCC 13.3.1 fail to compile parse-options.c due
to following error:

  parse-options.c: In function ‘options__order’:
  parse-options.c:832:9: error: ‘o’ may be used uninitialized [-Werror=maybe-uninitialized]
    832 |         memcpy(&amp;ordered[nr_opts], o, sizeof(*o));
        |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  parse-options.c:810:30: note: ‘o’ was declared here
    810 |         const struct option *o, *p = opts;
        |                              ^
  cc1: all warnings being treated as errors

Signed-off-by: Eder Zulian &lt;ezulian@redhat.com&gt;
Signed-off-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Acked-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Acked-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20241022172329.3871958-4-ezulian@redhat.com
Signed-off-by: Bin Lan &lt;bin.lan.cn@windriver.com&gt;
Signed-off-by: He Zhe &lt;zhe.he@windriver.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>Revert "sched/core: Reduce cost of sched_move_task when config autogroup"</title>
<updated>2025-03-28T21:03:33+00:00</updated>
<author>
<name>Dietmar Eggemann</name>
<email>dietmar.eggemann@arm.com</email>
</author>
<published>2025-03-14T15:13:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=8ece5abd74902edd5711cab8d1cc25f635733eff'/>
<id>urn:sha1:8ece5abd74902edd5711cab8d1cc25f635733eff</id>
<content type='text'>
commit 76f970ce51c80f625eb6ddbb24e9cb51b977b598 upstream.

This reverts commit eff6c8ce8d4d7faef75f66614dd20bb50595d261.

Hazem reported a 30% drop in UnixBench spawn test with commit
eff6c8ce8d4d ("sched/core: Reduce cost of sched_move_task when config
autogroup") on a m6g.xlarge AWS EC2 instance with 4 vCPUs and 16 GiB RAM
(aarch64) (single level MC sched domain):

  https://lkml.kernel.org/r/20250205151026.13061-1-hagarhem@amazon.com

There is an early bail from sched_move_task() if p-&gt;sched_task_group is
equal to p's 'cpu cgroup' (sched_get_task_group()). E.g. both are
pointing to taskgroup '/user.slice/user-1000.slice/session-1.scope'
(Ubuntu '22.04.5 LTS').

So in:

  do_exit()

    sched_autogroup_exit_task()

      sched_move_task()

        if sched_get_task_group(p) == p-&gt;sched_task_group
          return

        /* p is enqueued */
        dequeue_task()              \
        sched_change_group()        |
          task_change_group_fair()  |
            detach_task_cfs_rq()    |                              (1)
            set_task_rq()           |
            attach_task_cfs_rq()    |
        enqueue_task()              /

(1) isn't called for p anymore.

Turns out that the regression is related to sgs-&gt;group_util in
group_is_overloaded() and group_has_capacity(). If (1) isn't called for
all the 'spawn' tasks then sgs-&gt;group_util is ~900 and
sgs-&gt;group_capacity = 1024 (single CPU sched domain) and this leads to
group_is_overloaded() returning true (2) and group_has_capacity() false
(3) much more often compared to the case when (1) is called.

I.e. there are much more cases of 'group_is_overloaded' and
'group_fully_busy' in WF_FORK wakeup sched_balance_find_dst_cpu() which
then returns much more often a CPU != smp_processor_id() (5).

This isn't good for these extremely short running tasks (FORK + EXIT)
and also involves calling sched_balance_find_dst_group_cpu() unnecessary
(single CPU sched domain).

Instead if (1) is called for 'p-&gt;flags &amp; PF_EXITING' then the path
(4),(6) is taken much more often.

  select_task_rq_fair(..., wake_flags = WF_FORK)

    cpu = smp_processor_id()

    new_cpu = sched_balance_find_dst_cpu(..., cpu, ...)

      group = sched_balance_find_dst_group(..., cpu)

        do {

          update_sg_wakeup_stats()

            sgs-&gt;group_type = group_classify()

              if group_is_overloaded()                             (2)
                return group_overloaded

              if !group_has_capacity()                             (3)
                return group_fully_busy

              return group_has_spare                               (4)

        } while group

        if local_sgs.group_type &gt; idlest_sgs.group_type
          return idlest                                            (5)

        case group_has_spare:

          if local_sgs.idle_cpus &gt;= idlest_sgs.idle_cpus
            return NULL                                            (6)

Unixbench Tests './Run -c 4 spawn' on:

(a) VM AWS instance (m7gd.16xlarge) with v6.13 ('maxcpus=4 nr_cpus=4')
    and Ubuntu 22.04.5 LTS (aarch64).

    Shell &amp; test run in '/user.slice/user-1000.slice/session-1.scope'.

    w/o patch	w/ patch
    21005	27120

(b) i7-13700K with tip/sched/core ('nosmt maxcpus=8 nr_cpus=8') and
    Ubuntu 22.04.5 LTS (x86_64).

    Shell &amp; test run in '/A'.

    w/o patch	w/ patch
    67675	88806

CONFIG_SCHED_AUTOGROUP=y &amp; /sys/proc/kernel/sched_autogroup_enabled equal
0 or 1.

Reported-by: Hazem Mohamed Abuelfotoh &lt;abuehaze@amazon.com&gt;
Signed-off-by: Dietmar Eggemann &lt;dietmar.eggemann@arm.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Reviewed-by: Vincent Guittot &lt;vincent.guittot@linaro.org&gt;
Tested-by: Hagar Hemdan &lt;hagarhem@amazon.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Link: https://lore.kernel.org/r/20250314151345.275739-1-dietmar.eggemann@arm.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>KVM: arm64: Eagerly switch ZCR_EL{1,2}</title>
<updated>2025-03-28T21:03:32+00:00</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2025-03-21T00:13:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=c7762348038b3a2557c136032d65a3a4ca61f181'/>
<id>urn:sha1:c7762348038b3a2557c136032d65a3a4ca61f181</id>
<content type='text'>
[ Upstream commit 59419f10045bc955d2229819c7cf7a8b0b9c5b59 ]

In non-protected KVM modes, while the guest FPSIMD/SVE/SME state is live on the
CPU, the host's active SVE VL may differ from the guest's maximum SVE VL:

* For VHE hosts, when a VM uses NV, ZCR_EL2 contains a value constrained
  by the guest hypervisor, which may be less than or equal to that
  guest's maximum VL.

  Note: in this case the value of ZCR_EL1 is immaterial due to E2H.

* For nVHE/hVHE hosts, ZCR_EL1 contains a value written by the guest,
  which may be less than or greater than the guest's maximum VL.

  Note: in this case hyp code traps host SVE usage and lazily restores
  ZCR_EL2 to the host's maximum VL, which may be greater than the
  guest's maximum VL.

This can be the case between exiting a guest and kvm_arch_vcpu_put_fp().
If a softirq is taken during this period and the softirq handler tries
to use kernel-mode NEON, then the kernel will fail to save the guest's
FPSIMD/SVE state, and will pend a SIGKILL for the current thread.

This happens because kvm_arch_vcpu_ctxsync_fp() binds the guest's live
FPSIMD/SVE state with the guest's maximum SVE VL, and
fpsimd_save_user_state() verifies that the live SVE VL is as expected
before attempting to save the register state:

| if (WARN_ON(sve_get_vl() != vl)) {
|         force_signal_inject(SIGKILL, SI_KERNEL, 0, 0);
|         return;
| }

Fix this and make this a bit easier to reason about by always eagerly
switching ZCR_EL{1,2} at hyp during guest&lt;-&gt;host transitions. With this
happening, there's no need to trap host SVE usage, and the nVHE/nVHE
__deactivate_cptr_traps() logic can be simplified to enable host access
to all present FPSIMD/SVE/SME features.

In protected nVHE/hVHE modes, the host's state is always saved/restored
by hyp, and the guest's state is saved prior to exit to the host, so
from the host's PoV the guest never has live FPSIMD/SVE/SME state, and
the host's ZCR_EL1 is never clobbered by hyp.

Fixes: 8c8010d69c132273 ("KVM: arm64: Save/restore SVE state for nVHE")
Fixes: 2e3cf82063a00ea0 ("KVM: arm64: nv: Ensure correct VL is loaded before saving SVE state")
Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Reviewed-by: Mark Brown &lt;broonie@kernel.org&gt;
Tested-by: Mark Brown &lt;broonie@kernel.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Fuad Tabba &lt;tabba@google.com&gt;
Cc: Marc Zyngier &lt;maz@kernel.org&gt;
Cc: Oliver Upton &lt;oliver.upton@linux.dev&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Reviewed-by: Oliver Upton &lt;oliver.upton@linux.dev&gt;
Link: https://lore.kernel.org/r/20250210195226.1215254-9-mark.rutland@arm.com
Signed-off-by: Marc Zyngier &lt;maz@kernel.org&gt;
Signed-off-by: Mark Brown &lt;broonie@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>KVM: arm64: Mark some header functions as inline</title>
<updated>2025-03-28T21:03:32+00:00</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2025-03-21T00:13:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=4a397bf077e76ad061ccbf4e31e7f45fb6f1c0ce'/>
<id>urn:sha1:4a397bf077e76ad061ccbf4e31e7f45fb6f1c0ce</id>
<content type='text'>
[ Upstream commit f9dd00de1e53a47763dfad601635d18542c3836d ]

The shared hyp switch header has a number of static functions which
might not be used by all files that include the header, and when unused
they will provoke compiler warnings, e.g.

| In file included from arch/arm64/kvm/hyp/nvhe/hyp-main.c:8:
| ./arch/arm64/kvm/hyp/include/hyp/switch.h:703:13: warning: 'kvm_hyp_handle_dabt_low' defined but not used [-Wunused-function]
|   703 | static bool kvm_hyp_handle_dabt_low(struct kvm_vcpu *vcpu, u64 *exit_code)
|       |             ^~~~~~~~~~~~~~~~~~~~~~~
| ./arch/arm64/kvm/hyp/include/hyp/switch.h:682:13: warning: 'kvm_hyp_handle_cp15_32' defined but not used [-Wunused-function]
|   682 | static bool kvm_hyp_handle_cp15_32(struct kvm_vcpu *vcpu, u64 *exit_code)
|       |             ^~~~~~~~~~~~~~~~~~~~~~
| ./arch/arm64/kvm/hyp/include/hyp/switch.h:662:13: warning: 'kvm_hyp_handle_sysreg' defined but not used [-Wunused-function]
|   662 | static bool kvm_hyp_handle_sysreg(struct kvm_vcpu *vcpu, u64 *exit_code)
|       |             ^~~~~~~~~~~~~~~~~~~~~
| ./arch/arm64/kvm/hyp/include/hyp/switch.h:458:13: warning: 'kvm_hyp_handle_fpsimd' defined but not used [-Wunused-function]
|   458 | static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code)
|       |             ^~~~~~~~~~~~~~~~~~~~~
| ./arch/arm64/kvm/hyp/include/hyp/switch.h:329:13: warning: 'kvm_hyp_handle_mops' defined but not used [-Wunused-function]
|   329 | static bool kvm_hyp_handle_mops(struct kvm_vcpu *vcpu, u64 *exit_code)
|       |             ^~~~~~~~~~~~~~~~~~~

Mark these functions as 'inline' to suppress this warning. This
shouldn't result in any functional change.

At the same time, avoid the use of __alias() in the header and alias
kvm_hyp_handle_iabt_low() and kvm_hyp_handle_watchpt_low() to
kvm_hyp_handle_memory_fault() using CPP, matching the style in the rest
of the kernel. For consistency, kvm_hyp_handle_memory_fault() is also
marked as 'inline'.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Reviewed-by: Mark Brown &lt;broonie@kernel.org&gt;
Tested-by: Mark Brown &lt;broonie@kernel.org&gt;
Acked-by: Will Deacon &lt;will@kernel.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Fuad Tabba &lt;tabba@google.com&gt;
Cc: Marc Zyngier &lt;maz@kernel.org&gt;
Cc: Oliver Upton &lt;oliver.upton@linux.dev&gt;
Reviewed-by: Oliver Upton &lt;oliver.upton@linux.dev&gt;
Link: https://lore.kernel.org/r/20250210195226.1215254-8-mark.rutland@arm.com
Signed-off-by: Marc Zyngier &lt;maz@kernel.org&gt;
Signed-off-by: Mark Brown &lt;broonie@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>KVM: arm64: Refactor exit handlers</title>
<updated>2025-03-28T21:03:32+00:00</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2025-03-21T00:13:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=2e4f2c20db53fc38abdc442f6c3e0e4e252c7332'/>
<id>urn:sha1:2e4f2c20db53fc38abdc442f6c3e0e4e252c7332</id>
<content type='text'>
[ Upstream commit 9b66195063c5a145843547b1d692bd189be85287 ]

The hyp exit handling logic is largely shared between VHE and nVHE/hVHE,
with common logic in arch/arm64/kvm/hyp/include/hyp/switch.h. The code
in the header depends on function definitions provided by
arch/arm64/kvm/hyp/vhe/switch.c and arch/arm64/kvm/hyp/nvhe/switch.c
when they include the header.

This is an unusual header dependency, and prevents the use of
arch/arm64/kvm/hyp/include/hyp/switch.h in other files as this would
result in compiler warnings regarding missing definitions, e.g.

| In file included from arch/arm64/kvm/hyp/nvhe/hyp-main.c:8:
| ./arch/arm64/kvm/hyp/include/hyp/switch.h:733:31: warning: 'kvm_get_exit_handler_array' used but never defined
|   733 | static const exit_handler_fn *kvm_get_exit_handler_array(struct kvm_vcpu *vcpu);
|       |                               ^~~~~~~~~~~~~~~~~~~~~~~~~~
| ./arch/arm64/kvm/hyp/include/hyp/switch.h:735:13: warning: 'early_exit_filter' used but never defined
|   735 | static void early_exit_filter(struct kvm_vcpu *vcpu, u64 *exit_code);
|       |             ^~~~~~~~~~~~~~~~~

Refactor the logic such that the header doesn't depend on anything from
the C files. There should be no functional change as a result of this
patch.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Reviewed-by: Mark Brown &lt;broonie@kernel.org&gt;
Tested-by: Mark Brown &lt;broonie@kernel.org&gt;
Acked-by: Will Deacon &lt;will@kernel.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Fuad Tabba &lt;tabba@google.com&gt;
Cc: Marc Zyngier &lt;maz@kernel.org&gt;
Cc: Oliver Upton &lt;oliver.upton@linux.dev&gt;
Reviewed-by: Oliver Upton &lt;oliver.upton@linux.dev&gt;
Link: https://lore.kernel.org/r/20250210195226.1215254-7-mark.rutland@arm.com
Signed-off-by: Marc Zyngier &lt;maz@kernel.org&gt;
Signed-off-by: Mark Brown &lt;broonie@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>KVM: arm64: Remove VHE host restore of CPACR_EL1.SMEN</title>
<updated>2025-03-28T21:03:32+00:00</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2025-03-21T00:13:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=cb53828d6911d1c5890484b364c2403a19c30e1b'/>
<id>urn:sha1:cb53828d6911d1c5890484b364c2403a19c30e1b</id>
<content type='text'>
[ Upstream commit 407a99c4654e8ea65393f412c421a55cac539f5b ]

When KVM is in VHE mode, the host kernel tries to save and restore the
configuration of CPACR_EL1.SMEN (i.e. CPTR_EL2.SMEN when HCR_EL2.E2H=1)
across kvm_arch_vcpu_load_fp() and kvm_arch_vcpu_put_fp(), since the
configuration may be clobbered by hyp when running a vCPU. This logic
has historically been broken, and is currently redundant.

This logic was originally introduced in commit:

  861262ab86270206 ("KVM: arm64: Handle SME host state when running guests")

At the time, the VHE hyp code would reset CPTR_EL2.SMEN to 0b00 when
returning to the host, trapping host access to SME state. Unfortunately,
this was unsafe as the host could take a softirq before calling
kvm_arch_vcpu_put_fp(), and if a softirq handler were to use kernel mode
NEON the resulting attempt to save the live FPSIMD/SVE/SME state would
result in a fatal trap.

That issue was limited to VHE mode. For nVHE/hVHE modes, KVM always
saved/restored the host kernel's CPACR_EL1 value, and configured
CPTR_EL2.TSM to 0b0, ensuring that host usage of SME would not be
trapped.

The issue above was incidentally fixed by commit:

  375110ab51dec5dc ("KVM: arm64: Fix resetting SME trap values on reset for (h)VHE")

That commit changed the VHE hyp code to configure CPTR_EL2.SMEN to 0b01
when returning to the host, permitting host kernel usage of SME,
avoiding the issue described above. At the time, this was not identified
as a fix for commit 861262ab86270206.

Now that the host eagerly saves and unbinds its own FPSIMD/SVE/SME
state, there's no need to save/restore the state of the EL0 SME trap.
The kernel can safely save/restore state without trapping, as described
above, and will restore userspace state (including trap controls) before
returning to userspace.

Remove the redundant logic.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Reviewed-by: Mark Brown &lt;broonie@kernel.org&gt;
Tested-by: Mark Brown &lt;broonie@kernel.org&gt;
Acked-by: Will Deacon &lt;will@kernel.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Fuad Tabba &lt;tabba@google.com&gt;
Cc: Marc Zyngier &lt;maz@kernel.org&gt;
Cc: Oliver Upton &lt;oliver.upton@linux.dev&gt;
Reviewed-by: Oliver Upton &lt;oliver.upton@linux.dev&gt;
Link: https://lore.kernel.org/r/20250210195226.1215254-5-mark.rutland@arm.com
Signed-off-by: Marc Zyngier &lt;maz@kernel.org&gt;
[Update for rework of flags storage -- broonie]
Signed-off-by: Mark Brown &lt;broonie@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
</feed>
