This is consistent with what llvm-objdump does (see [1]) and allows
the LLVM disassembler to disassemble instructions not in the base
instruction set.
[1] https://reviews.llvm.org/D127741
Link: https://linux-review.googlesource.com/id/I52e4fef18d2e12b45f875231fa9d3efff2538fd4
Signed-off-by: Peter Collingbourne <pcc@google.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
binding->dev is protected on the write-side in
mp_dmabuf_devmem_uninstall() against concurrent writes, but due to the
concurrent bare reads in net_devmem_get_binding() and
validate_xmit_unreadable_skb() it should be wrapped in a
READ_ONCE/WRITE_ONCE pair to make sure no compiler optimizations play
with the underlying register in unforeseen ways.
Doesn't present a critical bug because the known compiler optimizations
don't result in bad behavior. There is no tearing on u64, and load
omissions/invented loads would only break if additional binding->dev
references were inlined together (they aren't right now).
This just more strictly follows the linux memory model (i.e.,
"Lock-Protected Writes With Lockless Reads" in
tools/memory-model/Documentation/access-marking.txt).
Fixes: bd61848900 ("net: devmem: Implement TX path")
Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
Link: https://patch.msgid.link/20260302-devmem-membar-fix-v2-1-5b33c9cbc28b@meta.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When/if a NIC resets, queues are deactivated by dev_deactivate_many(),
then reactivated when the reset operation completes.
fq_reset() removes all the skbs from various queues.
If we do not clear q->band_pkt_count[], these counters keep growing
and can eventually reach sch->limit, preventing new packets to be queued.
Many thanks to Praveen for discovering the root cause.
Fixes: 29f834aa32 ("net_sched: sch_fq: add 3 bands and WRR scheduling")
Diagnosed-by: Praveen Kaligineedi <pkaligineedi@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20260304015640.961780-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Instead of using struct timespec64 in scm_timestamping_internal,
use ktime_t, saving 24 bytes in kernel stack.
This makes tcp_update_recv_tstamps() small enough to be inlined.
The ktime_t -> timespec64 conversions happen after socket lock
has been released in tcp_recvmsg(), and only if the application
requested them.
$ scripts/bloat-o-meter -t vmlinux.0 vmlinux
add/remove: 0/2 grow/shrink: 5/4 up/down: 146/-277 (-131)
Function old new delta
tcp_zerocopy_receive 2383 2425 +42
mptcp_recvmsg 1565 1607 +42
tcp_recvmsg_locked 3797 3823 +26
put_cmsg_scm_timestamping64 131 149 +18
put_cmsg_scm_timestamping 131 149 +18
__pfx_tcp_update_recv_tstamps 16 - -16
do_tcp_getsockopt 4024 4006 -18
tcp_recv_timestamp 474 430 -44
tcp_zc_handle_leftover 417 371 -46
__sock_recv_timestamp 1087 1031 -56
tcp_update_recv_tstamps 97 - -97
Total: Before=25223788, After=25223657, chg -0.00%
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Link: https://patch.msgid.link/20260304012747.881644-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Fix some kernel-doc warnings in openvswitch.h:
Mark enum placeholders that are not used as "private" so that kernel-doc
comments are not needed for them.
Correct names for 2 enum values:
Warning: include/uapi/linux/openvswitch.h:300 Excess enum value
'@OVS_VPORT_UPCALL_SUCCESS' description in 'ovs_vport_upcall_attr'
Warning: include/uapi/linux/openvswitch.h:300 Excess enum value
'@OVS_VPORT_UPCALL_FAIL' description in 'ovs_vport_upcall_attr'
Convert one comment from "/**" kernel-doc to a plain C "/*" comment:
Warning: include/uapi/linux/openvswitch.h:638 This comment starts with
'/**', but isn't a kernel-doc comment.
* Omit attributes for notifications.
Add more kernel-doc:
- add kernel-doc for kernel-only enums;
- add missing kernel-doc for enum ovs_datapath_attr;
- add missing kernel-doc for enum ovs_flow_attr;
- add missing kernel-doc for enum ovs_sample_attr;
- add kernel-doc for enum ovs_check_pkt_len_attr;
- add kernel-doc for enum ovs_action_attr;
- add kernel-doc for enum ovs_action_push_eth;
- add kernel-doc for enum ovs_vport_attr;
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Ilya Maximets <i.maximets@ovn.org>
Link: https://patch.msgid.link/20260304012437.469151-1-rdunlap@infradead.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
tcp_do_parse_auth_options() fast path user is tcp_inbound_hash().
Move tcp_do_parse_auth_options() right before tcp_inbound_hash()
so that it can be (auto)inlined by the compiler.
As a bonus, stack canary is removed from tcp_inbound_hash().
Also use EXPORT_IPV6_MOD(tcp_do_parse_auth_options).
$ scripts/bloat-o-meter -t vmlinux.0 vmlinux
add/remove: 0/0 grow/shrink: 1/0 up/down: 131/0 (131)
Function old new delta
tcp_inbound_hash 565 696 +131
Total: Before=25223788, After=25223919, chg +0.00%
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260303191243.557245-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This reverts 28ee1b746f ("secure_seq: downgrade to per-host timestamp offsets")
tcp_tw_recycle went away in 2017.
Zhouyan Deng reported off-path TCP source port leakage via
SYN cookie side-channel that can be fixed in multiple ways.
One of them is to bring back TCP ports in TS offset randomization.
As a bonus, we perform a single siphash() computation
to provide both an ISN and a TS offset.
Fixes: 28ee1b746f ("secure_seq: downgrade to per-host timestamp offsets")
Reported-by: Zhouyan Deng <dengzhouyan_nwpu@163.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Acked-by: Florian Westphal <fw@strlen.de>
Link: https://patch.msgid.link/20260302205527.1982836-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When shrinking the number of real tx queues,
netif_set_real_num_tx_queues() calls qdisc_reset_all_tx_gt() to flush
qdiscs for queues which will no longer be used.
qdisc_reset_all_tx_gt() currently serializes qdisc_reset() with
qdisc_lock(). However, for lockless qdiscs, the dequeue path is
serialized by qdisc_run_begin/end() using qdisc->seqlock instead, so
qdisc_reset() can run concurrently with __qdisc_run() and free skbs
while they are still being dequeued, leading to UAF.
This can easily be reproduced on e.g. virtio-net by imposing heavy
traffic while frequently changing the number of queue pairs:
iperf3 -ub0 -c $peer -t 0 &
while :; do
ethtool -L eth0 combined 1
ethtool -L eth0 combined 2
done
With KASAN enabled, this leads to reports like:
BUG: KASAN: slab-use-after-free in __qdisc_run+0x133f/0x1760
...
Call Trace:
<TASK>
...
__qdisc_run+0x133f/0x1760
__dev_queue_xmit+0x248f/0x3550
ip_finish_output2+0xa42/0x2110
ip_output+0x1a7/0x410
ip_send_skb+0x2e6/0x480
udp_send_skb+0xb0a/0x1590
udp_sendmsg+0x13c9/0x1fc0
...
</TASK>
Allocated by task 1270 on cpu 5 at 44.558414s:
...
alloc_skb_with_frags+0x84/0x7c0
sock_alloc_send_pskb+0x69a/0x830
__ip_append_data+0x1b86/0x48c0
ip_make_skb+0x1e8/0x2b0
udp_sendmsg+0x13a6/0x1fc0
...
Freed by task 1306 on cpu 3 at 44.558445s:
...
kmem_cache_free+0x117/0x5e0
pfifo_fast_reset+0x14d/0x580
qdisc_reset+0x9e/0x5f0
netif_set_real_num_tx_queues+0x303/0x840
virtnet_set_channels+0x1bf/0x260 [virtio_net]
ethnl_set_channels+0x684/0xae0
ethnl_default_set_doit+0x31a/0x890
...
Serialize qdisc_reset_all_tx_gt() against the lockless dequeue path by
taking qdisc->seqlock for TCQ_F_NOLOCK qdiscs, matching the
serialization model already used by dev_reset_queue().
Additionally clear QDISC_STATE_NON_EMPTY after reset so the qdisc state
reflects an empty queue, avoiding needless re-scheduling.
Fixes: 6b3ba9146f ("net: sched: allow qdiscs to handle locking")
Signed-off-by: Koichiro Den <den@valinux.co.jp>
Link: https://patch.msgid.link/20260228145307.3955532-1-den@valinux.co.jp
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Eric Dumazet says:
====================
rfs: use high-order allocations for hash tables
This series adds rps_tag_ptr which encodes both a pointer
and a size of a power-of-two hash table in a single long word.
RFS hash tables (global and per rx-queue) are converted to rps_tag_ptr.
This removes a cache line miss, and allows high-order allocations.
The global hash table can benefit from huge pages.
====================
Link: https://patch.msgid.link/20260302181432.1836150-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Instead of storing the @log at the beginning of rps_dev_flow_table
use 5 low order bits of the rps_tag_ptr to store the log of the size.
This removes a potential cache line miss (for light traffic).
This allows us to switch to one high-order allocation instead of vmalloc()
when CONFIG_RFS_ACCEL is not set.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260302181432.1836150-8-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Remove rps_dev_flow_table_release() in favor of kvfree_rcu_mightsleep().
In the following pach, we will remove "u8 @log" field
and 'struct rps_dev_flow_table' size will be a power-of-two.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260302181432.1836150-7-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Use unrcu_pointer() and xchg() in store_rps_dev_flow_table_cnt()
instead of a dedicated spinlock.
Make a similar change in rx_queue_release(), so that both
functions use a similar construct and synchronization.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260302181432.1836150-6-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Instead of storing the @mask at the beginning of rps_sock_flow_table,
use 5 low order bits of the rps_tag_ptr to store the log of the size.
This removes a potential cache line miss to fetch @mask.
More importantly, we can switch to vmalloc_huge() without wasting memory.
Tested with:
numactl --interleave=all bash -c "echo 4194304 >/proc/sys/net/core/rps_sock_flow_entries"
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260302181432.1836150-5-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
In preparation of the following patch, abstract access
to the @mask field in 'struct rps_sock_flow_table'.
Also cleanup rps_sock_flow_sysctl() a bit :
- Rename orig_sock_table to o_sock_table.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260302181432.1836150-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Removing rcu_head (and @mask in a following patch)
will allow a power-of-two allocation and thus high-order
allocation for better performance.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260302181432.1836150-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add a new rps_tag_ptr type to encode a pointer and a size
to a power-of-two table.
Three helpers are added converting an rps_tag_ptr to:
1) A log of the size.
2) A mask : (size - 1).
3) A pointer to the array.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260302181432.1836150-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
udp_flow_src_port() and psp_write_headers() use ip_local_port_range.
ip_local_port_range is inclusive : all ports between min and max
can be used.
Before this patch, if ip_local_port_range was set to 40000-40001
40001 would not be used as a source port.
Use reciprocal_scale() to help code readability.
Not tagged for stable trees, as this change could break user
expectations.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20260302163933.1754393-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The q54sj108a2_debugfs_read function suffers from a stack buffer overflow
due to incorrect arguments passed to bin2hex(). The function currently
passes 'data' as the destination and 'data_char' as the source.
Because bin2hex() converts each input byte into two hex characters, a
32-byte block read results in 64 bytes of output. Since 'data' is only
34 bytes (I2C_SMBUS_BLOCK_MAX + 2), this writes 30 bytes past the end
of the buffer onto the stack.
Additionally, the arguments were swapped: it was reading from the
zero-initialized 'data_char' and writing to 'data', resulting in
all-zero output regardless of the actual I2C read.
Fix this by:
1. Expanding 'data_char' to 66 bytes to safely hold the hex output.
2. Correcting the bin2hex() argument order and using the actual read count.
3. Using a pointer to select the correct output buffer for the final
simple_read_from_buffer call.
Fixes: d014538aa3 ("hwmon: (pmbus) Driver for Delta power supplies Q54SJ108A2")
Cc: stable@vger.kernel.org
Signed-off-by: Sanman Pradhan <psanman@juniper.net>
Link: https://lore.kernel.org/r/20260304235116.1045-1-sanman.p211993@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
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Merge tag 'linux-can-fixes-for-7.0-20260302' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can
Marc Kleine-Budde says:
====================
pull-request: can 2026-03-02
The first 2 patches are by Oliver Hartkopp. The first fixes the
locking for CAN Broadcast Manager op runtime updates, the second fixes
the packet statisctics for the CAN dummy driver.
Alban Bedel's patch fixes a potential problem in the error path of the
mcp251x's ndo_open callback.
A patch by Ziyi Guo add USB endpoint type validation to the esd_usb
driver.
The next 6 patches are by Greg Kroah-Hartman and fix URB data parsing
for the ems_usb and ucan driver, fix URB anchoring in the etas_es58x,
and in the f81604 driver fix URB data parsing, add URB error handling
and fix URB anchoring.
A patch by me targets the gs_usb driver and fixes interoperability
with the CANable-2.5 firmware by always configuring the bit rate
before starting the device.
The last patch is by Frank Li and fixes a CHECK_DTBS warning for the
nxp,sja1000 dt-binding.
* tag 'linux-can-fixes-for-7.0-20260302' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can:
dt-bindings: net: can: nxp,sja1000: add reference to mc-peripheral-props.yaml
can: gs_usb: gs_can_open(): always configure bitrates before starting device
can: usb: f81604: correctly anchor the urb in the read bulk callback
can: usb: f81604: handle bulk write errors properly
can: usb: f81604: handle short interrupt urb messages properly
can: usb: etas_es58x: correctly anchor the urb in the read bulk callback
can: ucan: Fix infinite loop from zero-length messages
can: ems_usb: ems_usb_read_bulk_callback(): check the proper length of a message
can: esd_usb: add endpoint type validation
can: mcp251x: fix deadlock in error path of mcp251x_open
can: dummy_can: dummy_can_init(): fix packet statistics
can: bcm: fix locking for bcm_op runtime updates
====================
Link: https://patch.msgid.link/20260302152755.1700177-1-mkl@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Jakub Kicinski says:
====================
tools: ynl: tests: adjust Makefile to mimic ksft
Make a few minor adjustments to tools/net/ynl/tests/Makefile
to align its behavior more with how real kselftests behave.
This series allows running the YNL tests in NIPA with little
extra integration effort.
If anyone already integrated these tests into their CI minor
adjustments to the integration may be needed (due to patch 2).
====================
Link: https://patch.msgid.link/20260303163504.2084981-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Executors will need kselftest-list.txt so create it when
tests are installed.
Acked-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Link: https://patch.msgid.link/20260303163504.2084981-5-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
We have modelled the YNL tests after ksft to be able to reuse
the NIPA wrappers. Make sure YNL honors INSTALL_PATH not just
DESTDIR, ksft uses INSTALL_PATH.
Acked-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Link: https://patch.msgid.link/20260303163504.2084981-4-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Until commit 790792ebc9 ("tools: ynl: don't install tests")
YNL selftests were installed with all the other YNL outputs.
That's no longer the case, as tests are not really production
artifacts. Let's not install them in /usr/bin at all, and
mirror kselftest format more closely:
For: make -C tools/net/ynl/tests/ install DESTDIR=tmp
tmp/usr/share/kselftest
├── ktap_helpers.sh
└── ynl
├── test_ynl_cli.sh
└── test_ynl_ethtool.sh
Acked-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Link: https://patch.msgid.link/20260303163504.2084981-3-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Use the standard kselftest variable naming for tests in the Makefile.
NIPA depends on being able to selectively target tests by setting
those variables on the CLI.
Acked-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Link: https://patch.msgid.link/20260303163504.2084981-2-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The use of the 'port' argument name for functions implementing the MDIO
bus operations is misleading as the port address isn't equal to the
PHY address.
Rename the MDIO operation argument name to match the prototypes of
mdiobus_write, mdiobus_read, mdiobus_c45_read and mdiobus_c45_write.
Suggested-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/e1f4cb3bcffc7df9af0f2c9b673b14c7e1201c9a.1772507674.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The ports in the example device tree should not have a 'label'
property. Labels for all user ports have been removed from an earlier
submission, but this was overlooked in the case of the CPU port.
Remove 'cpu' port label from the example.
Suggested-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/61579de297eb636ec5f1e6c97d453e26abb0625d.1772507210.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add a test that verifies KVM's newly introduced behavior of synthesizing
a triple fault in L1 if L2 clears EFER.SVME without an L1 interception
(which is architecturally undefined).
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Link: https://patch.msgid.link/20260209195142.2554532-3-yosry.ahmed@linux.dev
Signed-off-by: Sean Christopherson <seanjc@google.com>
KVM tracks when EFER.SVME is set and cleared to initialize and tear down
nested state. However, it doesn't differentiate if EFER.SVME is getting
toggled in L1 or L2+. If L2 clears EFER.SVME, and L1 does not intercept
the EFER write, KVM exits guest mode and tears down nested state while
L2 is running, executing L1 without injecting a proper #VMEXIT.
According to the APM:
The effect of turning off EFER.SVME while a guest is running is
undefined; therefore, the VMM should always prevent guests from
writing EFER.
Since the behavior is architecturally undefined, KVM gets to choose what
to do. Inject a triple fault into L1 as a more graceful option that
running L1 with corrupted state.
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
base-commit: 95deaec3557dced322e2540bfa426e60e5373d46
Link: https://patch.msgid.link/20260209195142.2554532-2-yosry.ahmed@linux.dev
Signed-off-by: Sean Christopherson <seanjc@google.com>
After commit dd26d1b5d6ed ("KVM: nSVM: Cache all used fields from VMCB12"),
vmcb_is_dirty() has no callers. Remove the function.
Signed-off-by: Jim Mattson <jmattson@google.com>
Link: https://patch.msgid.link/20260224005500.1471972-2-jmattson@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Add a test that verifies that KVM correctly injects a #GP for nested
VMRUN and a shutdown for nested #VMEXIT, if the GPA of vmcb12 cannot be
mapped.
Signed-off-by: Yosry Ahmed <yosry@kernel.org>
Link: https://patch.msgid.link/20260303003421.2185681-27-yosry@kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
The 'misc_ctl' field in VMCB02 is taken as-is from VMCB01. However, the
only bit that needs to copied is SVM_MISC_ENABLE_NP, as all other known
bits in misc_ctl are related to SEV guests, and KVM doesn't support
nested virtualization for SEV guests.
Only copy SVM_MISC_ENABLE_NP to harden against future bugs if/when other
bits are set for L1 but should not be set for L2.
Opportunistically add a comment explaining why SVM_MISC_ENABLE_NP is
taken from VMCB01 and not VMCB02.
Suggested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Yosry Ahmed <yosry@kernel.org>
Link: https://patch.msgid.link/20260303003421.2185681-26-yosry@kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Make sure all fields used from vmcb12 in creating the vmcb02 are
sanitized, such that no unhandled or reserved bits end up in the vmcb02.
The following control fields are read from vmcb12 and have bits that are
either reserved or not handled/advertised by KVM: tlb_ctl, int_ctl,
int_state, int_vector, event_inj, misc_ctl, and misc_ctl2.
The following fields do not require any extra sanitizing:
- tlb_ctl: already being sanitized.
- int_ctl: bits from vmcb12 are copied bit-by-bit as needed.
- misc_ctl: only used in consistency checks (particularly NP_ENABLE).
- misc_ctl2: bits from vmcb12 are copied bit-by-bit as needed.
For the remaining fields (int_vector, int_state, and event_inj), make
sure only defined bits are copied from L1's vmcb12 into KVM'cache by
defining appropriate masks where needed.
Suggested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Yosry Ahmed <yosry@kernel.org>
Link: https://patch.msgid.link/20260303003421.2185681-25-yosry@kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
The APM defines possible values for TLB_CONTROL as 0, 1, 3, and 7 -- all
of which are always allowed for KVM guests as KVM always supports
X86_FEATURE_FLUSHBYASID. Only copy bits 0 to 2 from vmcb12's
TLB_CONTROL, such that no unhandled or reserved bits end up in vmcb02.
Note that TLB_CONTROL in vmcb12 is currently ignored by KVM, as it nukes
the TLB on nested transitions anyway (see
nested_svm_transition_tlb_flush()). However, such sanitization will be
needed once the TODOs there are addressed, and it's minimal churn to add
it now.
Signed-off-by: Yosry Ahmed <yosry@kernel.org>
Link: https://patch.msgid.link/20260303003421.2185681-24-yosry@kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Use PAGE_MASK to drop the lower bits from IOPM_BASE_PA and MSRPM_BASE_PA
while copying them instead of dropping the bits afterward with a
hardcoded mask.
No functional change intended.
Signed-off-by: Yosry Ahmed <yosry@kernel.org>
Link: https://patch.msgid.link/20260303003421.2185681-23-yosry@kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
All accesses to the vmcb12 in the guest memory on nested VMRUN are
limited to nested_svm_vmrun() copying vmcb12 fields and writing them on
failed consistency checks. However, vmcb12 remains mapped throughout
nested_svm_vmrun(). Mapping and unmapping around usages is possible,
but it becomes easy-ish to introduce bugs where 'vmcb12' is used after
being unmapped.
Move reading the vmcb12, copying to cache, and consistency checks from
nested_svm_vmrun() into a new helper, nested_svm_copy_vmcb12_to_cache()
to limit the scope of the mapping.
Signed-off-by: Yosry Ahmed <yosry@kernel.org>
Link: https://patch.msgid.link/20260303003421.2185681-22-yosry@kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Currently, most fields used from VMCB12 are cached in
svm->nested.{ctl/save}. This is mainly to avoid TOC-TOU bugs. However,
for the save area, only the fields used in the consistency checks (i.e.
nested_vmcb_check_save()) were being cached. Other fields are read
directly from guest memory in nested_vmcb02_prepare_save().
While probably benign, this still makes it possible for TOC-TOU bugs to
happen. For example, RAX, RSP, and RIP are read twice, once to store in
VMCB02, and once to store in vcpu->arch.regs. It is possible for the
guest to modify the value between both reads, potentially causing nasty
bugs.
Harden against such bugs by caching everything in svm->nested.save.
Cache all the needed fields, and keep all accesses to the VMCB12
strictly in nested_svm_vmrun() for caching and early error injection.
Following changes will further limit the access to the VMCB12 in the
nested VMRUN path.
Introduce vmcb12_is_dirty() to use with the cached control fields
instead of vmcb_is_dirty(), similar to vmcb12_is_intercept().
Opportunistically order the copies in __nested_copy_vmcb_save_to_cache()
by the order in which the fields are defined in struct vmcb_save_area.
Signed-off-by: Yosry Ahmed <yosry@kernel.org>
Link: https://patch.msgid.link/20260303003421.2185681-21-yosry@kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
'virt' is confusing in the VMCB because it is relative and ambiguous.
The 'virt_ext' field includes bits for LBR virtualization and
VMSAVE/VMLOAD virtualization, so it's just another miscellaneous control
field. Name it as such.
While at it, move the definitions of the bits below those for
'misc_ctl' and rename them for consistency.
Signed-off-by: Yosry Ahmed <yosry@kernel.org>
Link: https://patch.msgid.link/20260303003421.2185681-20-yosry@kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
The 'nested_ctl' field is misnamed. Although the first bit is for nested
paging, the other defined bits are for SEV/SEV-ES. Other bits in the
same field according to the APM (but not defined by KVM) include "Guest
Mode Execution Trap", "Enable INVLPGB/TLBSYNC", and other control bits
unrelated to 'nested'.
There is nothing common among these bits, so just name the field
misc_ctl. Also rename the flags accordingly.
Signed-off-by: Yosry Ahmed <yosry@kernel.org>
Link: https://patch.msgid.link/20260303003421.2185681-19-yosry@kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Grab svm->nested.ctl as vmcb12_ctrl when preparing the vmcb02 controls to
make it more obvious that much of the data is coming from vmcb12 (or
rather, a snapshot of vmcb12 at the time of L1's VMRUN).
Opportunistically reorder the variable definitions to create a pretty
reverse fir tree.
No functional change intended.
Cc: Yosry Ahmed <yosry.ahmed@linux.dev>
Reviewed-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Link: https://patch.msgid.link/20260218230958.2877682-9-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Move "bus_lock_rip" from "vmcb_ctrl_area_cached" to "svm_nested_state" as
"last_bus_lock_rip" to more accurately reflect what it tracks, and because
it is NOT a cached vmcb12 control field. The misplaced field isn't all
that apparent in the current code base, as KVM uses "svm->nested.ctl"
broadly, but the bad placement becomes glaringly obvious if
"svm->nested.ctl" is captured as a local "vmcb12_ctrl" variable.
No functional change intended.
Reviewed-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Link: https://patch.msgid.link/20260218230958.2877682-8-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Use vmcb12_is_intercept() instead of open-coding the intercept check.
No functional change intended.
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Link: https://patch.msgid.link/20260218230958.2877682-7-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Now that nested_vmcb02_recalc_intercepts() is explicitly scoped to deal
with *only* recalculating vmcb02 intercepts, rename its local variables to
use more intuivite names. The current "c", "h", and "g" local variables,
for the current VMCB, vmcb01, and (cached) vmcb12 respectively, are short
and sweet, but don't do much to help unfamiliar readers understand what
the code is doing.
Use vmcb12_ctrl/vmcb01/vmcb02/vmcb12_ctrl in lieu of c/h/g to make it clear
the function is updating intercepts in vmcb02 based on the intercepts in
vmcb01 and (cached) vmcb12.
Opportunistically change the existing WARN_ON to a WARN_ON_ONCE so that a
KVM bug doesn't unintentionally DoS the host.
No functional change intended.
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
[sean: use WARN_ON_ONCE, keep local vmcb12 cache as vmcb12_ctrl]
Link: https://patch.msgid.link/20260218230958.2877682-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Now that nested_vmcb02_recalc_intercepts() provides guardrails against it
being incorrectly called without vmcb02 active, invoke it directly from
nested_vmcb02_recalc_intercepts() instead of bouncing through
svm_mark_intercepts_dirty(), which unnecessarily marks vmcb01 as dirty.
Reviewed-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Link: https://patch.msgid.link/20260218230958.2877682-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
