September 2025 - Linux-kselftest-mirror

[PATCH 1/2] selftests/acct: add cleanup for leftover process_log binary

by Madhur Kumar

Some kselftests generate temporary binaries that are not tracked by TEST_GEN_PROGS. Add EXTRA_CLEAN entry to remove process_log during `make kselftest-clean`. Signed-off-by: Madhur Kumar <madhurkumar004(a)gmail.com> --- tools/testing/selftests/acct/Makefile | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/acct/Makefile b/tools/testing/selftests/acct/Makefile index 7e025099cf65..16eb97079e63 100644 --- a/tools/testing/selftests/acct/Makefile +++ b/tools/testing/selftests/acct/Makefile @@ -1,5 +1,6 @@ # SPDX-License-Identifier: GPL-2.0 TEST_GEN_PROGS := acct_syscall CFLAGS += -Wall +EXTRA_CLEAN := process_log -include ../lib.mk \ No newline at end of file +include ../lib.mk -- 2.51.0

2 days, 7 hours

2
8
0 0

[PATCH net-next 0/8] mptcp: receive path improvement

by Matthieu Baerts (NGI0)

This series includes several changes to the MPTCP RX path. The main goals are improving the RX performances, and increase the long term maintainability. Some changes reflects recent(ish) improvements introduced in the TCP stack: patch 1, 2 and 3 are the MPTCP counter part of SKB deferral free and auto-tuning improvements. Note that patch 3 could possibly fix additional issues, and overall such patch should protect from similar issues to arise in the future. Patches 4-7 are aimed at introducing the socket backlog usage which will be done in a later series to process the packets received by the different subflows while the msk socket is owned. Patch 8 is not related to the RX path, but it contains additional tests for new features recently introduced in net-next. Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org> --- Notes: - Sorry for sending this series that late, we had quite a few patches to upstream during this cycle. This is the last batch, and it has been heavily tested the last 2 weeks. - If there are some issues with some patches, but not with 1-3, it would be nice, if possible, if these 3 first patches can be accepted, to reduce the recently introduced gap with TCP. - Patches can be grouped like this if needed: 1-3, 4-5, 6-7, 8. 6-7 are preparing the ground for future on-going work, they can be dropped if there are issues with them. --- Matthieu Baerts (NGI0) (1): selftests: mptcp: join: validate new laminar endp Paolo Abeni (7): mptcp: leverage skb deferral free tcp: make tcp_rcvbuf_grow() accessible to mptcp code mptcp: rcvbuf auto-tuning improvement mptcp: introduce the mptcp_init_skb helper mptcp: remove unneeded mptcp_move_skb() mptcp: factor out a basic skb coalesce helper mptcp: minor move_skbs_to_msk() cleanup include/net/tcp.h | 1 + net/ipv4/tcp_input.c | 2 +- net/mptcp/protocol.c | 187 ++++++++++++------------ net/mptcp/protocol.h | 4 +- tools/testing/selftests/net/mptcp/mptcp_join.sh | 69 +++++++++ tools/testing/selftests/net/mptcp/pm_nl_ctl.c | 9 ++ 6 files changed, 177 insertions(+), 95 deletions(-) --- base-commit: 1493c18fe8696bfc758a97130a485fc4e08387f5 change-id: 20250927-net-next-mptcp-rcv-path-imp-192d8c24c9c7 Best regards, -- Matthieu Baerts (NGI0) <matttbe(a)kernel.org>

2 days, 13 hours

1
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[PATCH v3 net-next 00/12] AccECN protocol case handling series

by chia-yu.chang＠nokia-bell-labs.com

From: Chia-Yu Chang <chia-yu.chang(a)nokia-bell-labs.com> Hello, Plesae find the v2 AccECN case handling patch series, which covers several excpetional case handling of Accurate ECN spec (RFC9768), adds new identifiers to be used by CC modules, adds ecn_delta into rate_sample, and keeps the ACE counter for computation, etc. This patch series is part of the full AccECN patch series, which is available at https://github.com/L4STeam/linux-net-next/commits/upstream_l4steam/ Best regards, Chia-Yu --- v3: - Add additional min() check if pkts_acked_ewma is not initialized in #1. - Change TCP_CONG_WANTS_ECT_1 into individual flag add helper function INET_ECN_xmit_wants_ect_1() in #3. - Add empty line between variable declarations and code in #4. - Update commit message to fix old AccECN commits in #5. - Remove unnecessary brackets in #10. - Move patch #3 in v2 to a later Prague patch serise and remove patch #13 in v2. --- Chia-Yu Chang (10): tcp: L4S ECT(1) identifier and NEEDS_ACCECN for CC modules tcp: disable RFC3168 fallback identifier for CC modules tcp: accecn: handle unexpected AccECN negotiation feedback tcp: accecn: retransmit downgraded SYN in AccECN negotiation tcp: move increment of num_retrans tcp: accecn: retransmit SYN/ACK without AccECN option or non-AccECN SYN/ACK tcp: accecn: unset ECT if receive or send ACE=0 in AccECN negotiaion tcp: accecn: fallback outgoing half link to non-AccECN tcp: accecn: verify ACE counter in 1st ACK after AccECN negotiation tcp: accecn: enable AccECN Ilpo Järvinen (2): tcp: try to avoid safer when ACKs are thinned gro: flushing when CWR is set negatively affects AccECN .../networking/net_cachelines/tcp_sock.rst | 1 + include/linux/tcp.h | 1 + include/net/inet_ecn.h | 20 ++++- include/net/tcp.h | 32 ++++++- include/net/tcp_ecn.h | 90 +++++++++++++------ net/ipv4/sysctl_net_ipv4.c | 2 +- net/ipv4/tcp.c | 2 + net/ipv4/tcp_cong.c | 10 ++- net/ipv4/tcp_input.c | 49 ++++++++-- net/ipv4/tcp_minisocks.c | 40 ++++++--- net/ipv4/tcp_offload.c | 3 +- net/ipv4/tcp_output.c | 35 +++++--- 12 files changed, 218 insertions(+), 67 deletions(-) -- 2.34.1

2 days, 14 hours

1
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[PATCH net-next 00/13] selftests: Mark auto-deferring functions clearly

by Petr Machata

selftests/net/lib.sh contains a suite of iproute2 wrappers that automatically schedule the corresponding cleanup through defer. The fact they do so is however not immediately obvious, one needs to know which functions are handling the deferral behind the scenes, and which expect the caller to handle cleanups themselves. A convention for these auto-deferring functions would help both writing and patch review. This patchset does so by marking these functions with an adf_ prefix. We already have a few such functions: forwarding/lib.sh has adf_mcd_start() and a few selftests add private helpers that conform to this convention. Patches #1 to #8 gradually convert individual functions, one per patch. Patch #9 renames an auto-deferring private helpers named dfr_* to adf_*. The plan is not to retro-rename all private helpers, but I happened to know about this one. Patches #10 to #12 introduce several autodefer helpers for commonly used forwarding/lib.sh functions, and opportunistically convert straightforward instances of 'action; defer counteraction' to the new helpers. Patch #13 adds some README verbiage to pitch defer and the adf_* convention. Petr Machata (13): selftests: net: lib: Rename ip_link_add() to adf_* selftests: net: lib: Rename ip_link_set_master() to adf_* selftests: net: lib: Rename ip_link_set_addr() to adf_* selftests: net: lib: Rename ip_link_set_up() to adf_* selftests: net: lib: Rename ip_link_set_down() to adf_* selftests: net: lib: Rename ip_addr_add() to adf_* selftests: net: lib: Rename ip_route_add() to adf_* selftests: net: lib: Rename bridge_vlan_add() to adf_* selftests: net: vlan_bridge_binding: Rename dfr_set_binding_*() to adf_* selftests: forwarding: lib: Add an autodefer variant of vrf_prepare() selftests: forwarding: lib: Add an autodefer variant of simple_if_init() selftests: forwarding: lib: Add an autodefer variant of forwarding_enable() selftests: forwarding: README: Mention defer, adf_ .../drivers/net/mlxsw/devlink_trap_policer.sh | 9 +- .../drivers/net/mlxsw/qos_ets_strict.sh | 12 +- .../drivers/net/mlxsw/qos_max_descriptors.sh | 9 +- .../drivers/net/mlxsw/qos_mc_aware.sh | 12 +- .../drivers/net/mlxsw/sch_red_core.sh | 6 +- tools/testing/selftests/net/fdb_notify.sh | 26 ++-- tools/testing/selftests/net/forwarding/README | 15 ++ .../net/forwarding/bridge_activity_notify.sh | 21 ++- .../net/forwarding/bridge_fdb_local_vlan_0.sh | 65 ++++---- tools/testing/selftests/net/forwarding/lib.sh | 18 +++ .../selftests/net/forwarding/sch_ets_core.sh | 9 +- .../selftests/net/forwarding/sch_red.sh | 12 +- .../selftests/net/forwarding/sch_tbf_core.sh | 6 +- .../net/forwarding/vxlan_bridge_1q_mc_ul.sh | 141 +++++++++--------- .../net/forwarding/vxlan_reserved.sh | 33 ++-- tools/testing/selftests/net/lib.sh | 16 +- .../net/test_vxlan_fdb_changelink.sh | 8 +- .../selftests/net/vlan_bridge_binding.sh | 44 +++--- 18 files changed, 225 insertions(+), 237 deletions(-) -- 2.49.0

2 days, 21 hours

3
27
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[PATCH net-next 00/15] mptcp: pm: special case for c-flag + luminar endp

by Matthieu Baerts (NGI0)

Here are some patches for the MPTCP PM, including some refactoring that I thought it would be best to send at the end of a cycle to avoid conflicts between net and net-next that could last a few weeks. The most interesting changes are in the first and last patch, the rest are patches refactoring the code & tests to validate the modifications. - Patches 1 & 2: When servers set the C-flag in their MP_CAPABLE to tell clients not to create subflows to the initial address and port -- e.g. a deployment behind a L4 load balancer like a typical CDN deployment -- clients will not use their other endpoints when default settings are used. That's because the in-kernel path-manager uses the 'subflow' endpoints to create subflows only to the initial address and port. The first patch fixes that (for >=v5.14), and the second one validates it. - Patches 3-14: various patches refactoring the code around the in-kernel PM (mainly): split too long functions, rename variables and functions to avoid confusions, reduce structure size, and compare IDs instead of IP addresses. Note that one patch modifies one internal variable used in one BPF selftest. - Patch 15: ability to control endpoints that are used in reaction to a new address announced by the other peer. With that, endpoints can be used only once. Signed-off-by: Matthieu Baerts (NGI0) <matttbe(a)kernel.org> --- Notes: - Patches 1 & 2 are sent to net-next on purpose: to delay a bit the backports, just in case. Plus we are at the end of a cycle, and not to delay the other refactoring patches. - Sorry, I wanted to send this series earlier on, but due to some unrelated issues (and holiday), it got delayed. Most patches are pure refactoring ones. --- Matthieu Baerts (NGI0) (15): mptcp: pm: in-kernel: usable client side with C-flag selftests: mptcp: join: validate C-flag + def limit mptcp: pm: in-kernel: refactor fill_local_addresses_vec mptcp: pm: in-kernel: refactor fill_remote_addresses_vec mptcp: pm: rename 'subflows' to 'extra_subflows' mptcp: pm: in-kernel: rename 'subflows_max' to 'limit_extra_subflows' mptcp: pm: in-kernel: rename 'add_addr_signal_max' to 'endp_signal_max' mptcp: pm: in-kernel: rename 'add_addr_accept_max' to 'limit_add_addr_accepted' mptcp: pm: in-kernel: rename 'local_addr_max' to 'endp_subflow_max' mptcp: pm: in-kernel: rename 'local_addr_list' to 'endp_list' mptcp: pm: in-kernel: rename 'addrs' to 'endpoints' mptcp: pm: in-kernel: remove stale_loss_cnt mptcp: pm: in-kernel: reduce pernet struct size mptcp: pm: in-kernel: compare IDs instead of addresses mptcp: pm: in-kernel: add laminar endpoints include/uapi/linux/mptcp.h | 11 +- net/mptcp/pm.c | 32 +- net/mptcp/pm_kernel.c | 569 ++++++++++++++-------- net/mptcp/pm_userspace.c | 2 +- net/mptcp/protocol.h | 21 +- net/mptcp/sockopt.c | 22 +- tools/testing/selftests/bpf/progs/mptcp_subflow.c | 2 +- tools/testing/selftests/net/mptcp/mptcp_join.sh | 11 + 8 files changed, 441 insertions(+), 229 deletions(-) --- base-commit: a1f1f2422e098485b09e55a492de05cf97f9954d change-id: 20250925-net-next-mptcp-c-flag-laminar-f8442e4d4bd9 Best regards, -- Matthieu Baerts (NGI0) <matttbe(a)kernel.org>

2 days, 21 hours

2
16
0 0

[PATCH RFC bpf-next v2 0/5] Add the the capability to load HW RX checsum in eBPF programs

by Lorenzo Bianconi

Introduce bpf_xdp_metadata_rx_checksum() kfunc in order to load the HW RX cheksum results in the eBPF program binded to the NIC. Implement xmo_rx_checksum callback for veth and ice drivers. Please note ice support changes are just compile-tested at the moment. --- Changes in RFC v2: - Squash patch 1/6 and 2/6 - Introduce enum xdp_checksum definitions - Rework ice support to reuse ice_rx_csum codebase --- Lorenzo Bianconi (5): netlink: specs: Add XDP RX checksum capability to XDP metadata specs net: veth: Add xmo_rx_checksum callback to veth driver net: ice: Add xmo_rx_checksum callback selftests/bpf: Add selftest support for bpf_xdp_metadata_rx_checksum selftests/bpf: Add bpf_xdp_metadata_rx_checksum support to xdp_hw_metadat prog Documentation/netlink/specs/netdev.yaml | 5 + drivers/net/ethernet/intel/ice/ice_base.c | 1 + drivers/net/ethernet/intel/ice/ice_txrx.h | 1 + drivers/net/ethernet/intel/ice/ice_txrx_lib.c | 125 +++++++++++++-------- drivers/net/veth.c | 20 ++++ include/net/xdp.h | 14 +++ net/core/xdp.c | 29 +++++ .../selftests/bpf/prog_tests/xdp_metadata.c | 7 ++ .../testing/selftests/bpf/progs/xdp_hw_metadata.c | 7 ++ tools/testing/selftests/bpf/progs/xdp_metadata.c | 1 + tools/testing/selftests/bpf/xdp_hw_metadata.c | 27 +++++ tools/testing/selftests/bpf/xdp_metadata.h | 13 +++ 12 files changed, 206 insertions(+), 44 deletions(-) --- base-commit: 5e3fee34f626a8cb8715f5b5409416c481714ebf change-id: 20250925-bpf-xdp-meta-rxcksum-900685e2909d Best regards, -- Lorenzo Bianconi <lorenzo(a)kernel.org>

2 days, 22 hours

5
17
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[PATCH v2] selftest: net: Fix error message if empty variable

by Alessandro Zanni

Fix to avoid cases where the `res` shell variable is empty in script comparisons. The comparison has been modified into string comparison to handle other possible values the variable could assume. The issue can be reproduced with the command: make kselftest TARGETS=net It solves the error: ./tfo_passive.sh: line 98: [: -eq: unary operator expected Signed-off-by: Alessandro Zanni <alessandro.zanni87(a)gmail.com> --- Notes: v2: edit condition to handle strings tools/testing/selftests/net/tfo_passive.sh | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/net/tfo_passive.sh b/tools/testing/selftests/net/tfo_passive.sh index 80bf11fdc046..a4550511830a 100755 --- a/tools/testing/selftests/net/tfo_passive.sh +++ b/tools/testing/selftests/net/tfo_passive.sh @@ -95,7 +95,7 @@ wait res=$(cat $out_file) rm $out_file -if [ $res -eq 0 ]; then +if [ "$res" = "0" ]; then echo "got invalid NAPI ID from passive TFO socket" cleanup_ns exit 1 -- 2.43.0

3 days

3
2
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[PATCH net-next] selftests: drv-net: Enable BTF

by Stanislav Fomichev

Commit fec2e55bdef ("selftests: drv-net: Pull data before parsing headers") added __ksym external symbol to xdp_native.bpf.c which now requires a kernel with BTF. Enable BTF for driver selftests. Before: # TAP version 13 # 1..10 # # Exception| Traceback (most recent call last): # # Exception| File "/home/sdf/src/linux/tools/testing/selftests/net/lib/py/ksft.py", line 244, in ksft_run # # Exception| case(*args) # # Exception| ~~~~^^^^^^^ # # Exception| File "/home/sdf/src/linux/tools/testing/selftests/drivers/net/./xdp.py", line 231, in test_xdp_native_pass_sb # # Exception| _test_pass(cfg, bpf_info, 256) # # Exception| ~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^ # # Exception| File "/home/sdf/src/linux/tools/testing/selftests/drivers/net/./xdp.py", line 209, in _test_pass # # Exception| prog_info = _load_xdp_prog(cfg, bpf_info) # # Exception| File "/home/sdf/src/linux/tools/testing/selftests/drivers/net/./xdp.py", line 114, in _load_xdp_prog # # Exception| cmd( # # Exception| ~~~^ # # Exception| f"ip link set dev {cfg.ifname} mtu {bpf_info.mtu} xdpdrv obj {abs_path} sec {bpf_info.xdp_sec}", # # Exception| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ # # Exception| shell=True # # Exception| ^^^^^^^^^^ # # Exception| ) # # Exception| ^ # # Exception| File "/home/sdf/src/linux/tools/testing/selftests/net/lib/py/utils.py", line 75, in __init__ # # Exception| self.process(terminate=False, fail=fail, timeout=timeout) # # Exception| ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ # # Exception| File "/home/sdf/src/linux/tools/testing/selftests/net/lib/py/utils.py", line 95, in process # # Exception| raise CmdExitFailure("Command failed: %s\nSTDOUT: %s\nSTDERR: %s" % # # Exception| (self.proc.args, stdout, stderr), self) # # Exception| net.lib.py.utils.CmdExitFailure: Command failed: ip link set dev eni30773np1 mtu 1500 xdpdrv obj /home/sdf/src/linux/tools/testing/selftests/net/lib/xdp_native.bpf.o sec xdp # # Exception| STDOUT: b'' # # Exception| STDERR: b"libbpf: kernel BTF is missing at '/sys/kernel/btf/vmlinux', was CONFIG_DEBUG_INFO_BTF enabled?\nlibbpf: failed to find '.BTF' ELF section in /lib/modules/6.17.0-rc6-virtme/build/vmlinux\nlibbpf: failed to find valid kernel BTF\nlib bpf: Error loading vmlinux BTF: -3\nlibbpf: failed to load object '/home/sdf/src/linux/tools/testing/selftests/net/lib/xdp_native.bpf.o'\n" # not ok 1 xdp.test_xdp_native_pass_sb ... After: # TAP version 13 # 1..10 # ok 1 xdp.test_xdp_native_pass_sb # ok 2 xdp.test_xdp_native_pass_mb # ok 3 xdp.test_xdp_native_drop_sb # ok 4 xdp.test_xdp_native_drop_mb # ok 5 xdp.test_xdp_native_tx_sb # ok 6 xdp.test_xdp_native_tx_mb # # Ignoring SIGTERM (cnt: 2), already exiting... # # Ignoring SIGTERM (cnt: 3), already exiting... # # Exception| Traceback (most recent call last): # # Exception| File "/home/sdf/src/linux/tools/testing/selftests/net/lib/py/ksft.py", line 244, in ksft_run # # Exception| case(*args) # # Exception| ~~~~^^^^^^^ # # Exception| File "/home/sdf/src/linux/tools/testing/selftests/drivers/net/./xdp.py", line 506, in test_xdp_native_adjst_taa # # Exception| res = _test_xdp_native_tail_adjst( # # Exception| cfg, # # Exception| pkt_sz_lst, # # Exception| offset_lst, # # Exception| ) # # Exception| File "/home/sdf/src/linux/tools/testing/selftests/drivers/net/./xdp.py", line 467, in _test_xdp_native_tail_adt # # Exception| recvd_str = _exchg_udp(cfg, port, test_str) # # Exception| File "/home/sdf/src/linux/tools/testing/selftests/drivers/net/./xdp.py", line 72, in _exchg_udp # # Exception| with bkg(rx_udp_cmd, exit_wait=True) as nc: # # Exception| ~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^ # # Exception| File "/home/sdf/src/linux/tools/testing/selftests/net/lib/py/utils.py", line 137, in __exit__ # # Exception| return self.process(terminate=terminate, fail=self.check_fail) # # Exception| ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ # # Exception| File "/home/sdf/src/linux/tools/testing/selftests/net/lib/py/utils.py", line 85, in process # # Exception| stdout, stderr = self.proc.communicate(timeout) # # Exception| ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^ # # Exception| File "/usr/lib/python3.13/subprocess.py", line 1222, in communicate # # Exception| stdout, stderr = self._communicate(input, endtime, timeout) # # Exception| ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^ # # Exception| File "/usr/lib/python3.13/subprocess.py", line 2128, in _communicate # # Exception| ready = selector.select(timeout) # # Exception| File "/usr/lib/python3.13/selectors.py", line 398, in select # # Exception| fd_event_list = self._selector.poll(timeout) # # Exception| File "/home/sdf/src/linux/tools/testing/selftests/net/lib/py/ksft.py", line 208, in _ksft_intr # # Exception| raise KsftTerminate() # # Exception| net.lib.py.ksft.KsftTerminate # # Stopping tests due to KsftTerminate. # not ok 7 xdp.test_xdp_native_adjst_tail_grow_data # # Totals: pass:6 fail:1 xfail:0 xpass:0 skip:0 error:0 Signed-off-by: Stanislav Fomichev <sdf(a)fomichev.me> --- tools/testing/selftests/drivers/net/config | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/testing/selftests/drivers/net/config b/tools/testing/selftests/drivers/net/config index f27172ddee0a..da5a5a94fa6a 100644 --- a/tools/testing/selftests/drivers/net/config +++ b/tools/testing/selftests/drivers/net/config @@ -5,3 +5,5 @@ CONFIG_NETCONSOLE=m CONFIG_NETCONSOLE_DYNAMIC=y CONFIG_NETCONSOLE_EXTENDED_LOG=y CONFIG_XDP_SOCKETS=y +CONFIG_DEBUG_INFO_BTF=y +CONFIG_DEBUG_INFO_BTF_MODULES=n -- 2.51.0

3 days, 1 hour

2
1
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[PATCH v19 00/27] riscv control-flow integrity for usermode

by Deepak Gupta

Basics and overview =================== Software with larger attack surfaces (e.g. network facing apps like databases, browsers or apps relying on browser runtimes) suffer from memory corruption issues which can be utilized by attackers to bend control flow of the program to eventually gain control (by making their payload executable). Attackers are able to perform such attacks by leveraging call-sites which rely on indirect calls or return sites which rely on obtaining return address from stack memory. To mitigate such attacks, risc-v extension zicfilp enforces that all indirect calls must land on a landing pad instruction `lpad` else cpu will raise software check exception (a new cpu exception cause code on riscv). Similarly for return flow, risc-v extension zicfiss extends architecture with - `sspush` instruction to push return address on a shadow stack - `sspopchk` instruction to pop return address from shadow stack and compare with input operand (i.e. return address on stack) - `sspopchk` to raise software check exception if comparision above was a mismatch - Protection mechanism using which shadow stack is not writeable via regular store instructions More information an details can be found at extensions github repo [1]. Equivalent to landing pad (zicfilp) on x86 is `ENDBRANCH` instruction in Intel CET [3] and branch target identification (BTI) [4] on arm. Similarly x86's Intel CET has shadow stack [5] and arm64 has guarded control stack (GCS) [6] which are very similar to risc-v's zicfiss shadow stack. x86 and arm64 support for user mode shadow stack is already in mainline. Kernel awareness for user control flow integrity ================================================ This series picks up Samuel Holland's envcfg changes [2] as well. So if those are being applied independently, they should be removed from this series. Enabling: In order to maintain compatibility and not break anything in user mode, kernel doesn't enable control flow integrity cpu extensions on binary by default. Instead exposes a prctl interface to enable, disable and lock the shadow stack or landing pad feature for a task. This allows userspace (loader) to enumerate if all objects in its address space are compiled with shadow stack and landing pad support and accordingly enable the feature. Additionally if a subsequent `dlopen` happens on a library, user mode can take a decision again to disable the feature (if incoming library is not compiled with support) OR terminate the task (if user mode policy is strict to have all objects in address space to be compiled with control flow integirty cpu feature). prctl to enable shadow stack results in allocating shadow stack from virtual memory and activating for user address space. x86 and arm64 are also following same direction due to similar reason(s). clone/fork: On clone and fork, cfi state for task is inherited by child. Shadow stack is part of virtual memory and is a writeable memory from kernel perspective (writeable via a restricted set of instructions aka shadow stack instructions) Thus kernel changes ensure that this memory is converted into read-only when fork/clone happens and COWed when fault is taken due to sspush, sspopchk or ssamoswap. In case `CLONE_VM` is specified and shadow stack is to be enabled, kernel will automatically allocate a shadow stack for that clone call. map_shadow_stack: x86 introduced `map_shadow_stack` system call to allow user space to explicitly map shadow stack memory in its address space. It is useful to allocate shadow for different contexts managed by a single thread (green threads or contexts) risc-v implements this system call as well. signal management: If shadow stack is enabled for a task, kernel performs an asynchronous control flow diversion to deliver the signal and eventually expects userspace to issue sigreturn so that original execution can be resumed. Even though resume context is prepared by kernel, it is in user space memory and is subject to memory corruption and corruption bugs can be utilized by attacker in this race window to perform arbitrary sigreturn and eventually bypass cfi mechanism. Another issue is how to ensure that cfi related state on sigcontext area is not trampled by legacy apps or apps compiled with old kernel headers. In order to mitigate control-flow hijacting, kernel prepares a token and place it on shadow stack before signal delivery and places address of token in sigcontext structure. During sigreturn, kernel obtains address of token from sigcontext struture, reads token from shadow stack and validates it and only then allow sigreturn to succeed. Compatiblity issue is solved by adopting dynamic sigcontext management introduced for vector extension. This series re-factor the code little bit to allow future sigcontext management easy (as proposed by Andy Chiu from SiFive) config and compilation: Introduce a new risc-v config option `CONFIG_RISCV_USER_CFI`. Selecting this config option picks the kernel support for user control flow integrity. This optin is presented only if toolchain has shadow stack and landing pad support. And is on purpose guarded by toolchain support. Reason being that eventually vDSO also needs to be compiled in with shadow stack and landing pad support. vDSO compile patches are not included as of now because landing pad labeling scheme is yet to settle for usermode runtime. To get more information on kernel interactions with respect to zicfilp and zicfiss, patch series adds documentation for `zicfilp` and `zicfiss` in following: Documentation/arch/riscv/zicfiss.rst Documentation/arch/riscv/zicfilp.rst How to test this series ======================= Toolchain --------- $ git clone git@github.com:sifive/riscv-gnu-toolchain.git -b cfi-dev $ riscv-gnu-toolchain/configure --prefix=<path-to-where-to-build> --with-arch=rv64gc_zicfilp_zicfiss --enable-linux --disable-gdb --with-extra-multilib-test="rv64gc_zicfilp_zicfiss-lp64d:-static" $ make -j$(nproc) Qemu ---- Get the lastest qemu $ cd qemu $ mkdir build $ cd build $ ../configure --target-list=riscv64-softmmu $ make -j$(nproc) Opensbi ------- $ git clone git@github.com:deepak0414/opensbi.git -b v6_cfi_spec_split_opensbi $ make CROSS_COMPILE=<your riscv toolchain> -j$(nproc) PLATFORM=generic Linux ----- Running defconfig is fine. CFI is enabled by default if the toolchain supports it. $ make ARCH=riscv CROSS_COMPILE=<path-to-cfi-riscv-gnu-toolchain>/build/bin/riscv64-unknown-linux-gnu- -j$(nproc) defconfig $ make ARCH=riscv CROSS_COMPILE=<path-to-cfi-riscv-gnu-toolchain>/build/bin/riscv64-unknown-linux-gnu- -j$(nproc) In case you're building your own rootfs using toolchain, please make sure you pick following patch to ensure that vDSO compiled with lpad and shadow stack. "arch/riscv: compile vdso with landing pad" Branch where above patch can be picked https://github.com/deepak0414/linux-riscv-cfi/tree/vdso_user_cfi_v6.12-rc1 Running ------- Modify your qemu command to have: -bios <path-to-cfi-opensbi>/build/platform/generic/firmware/fw_dynamic.bin -cpu rv64,zicfilp=true,zicfiss=true,zimop=true,zcmop=true vDSO related Opens (in the flux) ================================= I am listing these opens for laying out plan and what to expect in future patch sets. And of course for the sake of discussion. Shadow stack and landing pad enabling in vDSO ---------------------------------------------- vDSO must have shadow stack and landing pad support compiled in for task to have shadow stack and landing pad support. This patch series doesn't enable that (yet). Enabling shadow stack support in vDSO should be straight forward (intend to do that in next versions of patch set). Enabling landing pad support in vDSO requires some collaboration with toolchain folks to follow a single label scheme for all object binaries. This is necessary to ensure that all indirect call-sites are setting correct label and target landing pads are decorated with same label scheme. How many vDSOs --------------- Shadow stack instructions are carved out of zimop (may be operations) and if CPU doesn't implement zimop, they're illegal instructions. Kernel could be running on a CPU which may or may not implement zimop. And thus kernel will have to carry 2 different vDSOs and expose the appropriate one depending on whether CPU implements zimop or not. References ========== [1] - https://github.com/riscv/riscv-cfi [2] - https://lore.kernel.org/all/20240814081126.956287-1-samuel.holland@sifive.c… [3] - https://lwn.net/Articles/889475/ [4] - https://developer.arm.com/documentation/109576/0100/Branch-Target-Identific… [5] - https://www.intel.com/content/dam/develop/external/us/en/documents/catc17-i… [6] - https://lwn.net/Articles/940403/ To: Thomas Gleixner <tglx(a)linutronix.de> To: Ingo Molnar <mingo(a)redhat.com> To: Borislav Petkov <bp(a)alien8.de> To: Dave Hansen <dave.hansen(a)linux.intel.com> To: x86(a)kernel.org To: H. Peter Anvin <hpa(a)zytor.com> To: Andrew Morton <akpm(a)linux-foundation.org> To: Liam R. Howlett <Liam.Howlett(a)oracle.com> To: Vlastimil Babka <vbabka(a)suse.cz> To: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> To: Paul Walmsley <paul.walmsley(a)sifive.com> To: Palmer Dabbelt <palmer(a)dabbelt.com> To: Albert Ou <aou(a)eecs.berkeley.edu> To: Conor Dooley <conor(a)kernel.org> To: Rob Herring <robh(a)kernel.org> To: Krzysztof Kozlowski <krzk+dt(a)kernel.org> To: Arnd Bergmann <arnd(a)arndb.de> To: Christian Brauner <brauner(a)kernel.org> To: Peter Zijlstra <peterz(a)infradead.org> To: Oleg Nesterov <oleg(a)redhat.com> To: Eric Biederman <ebiederm(a)xmission.com> To: Kees Cook <kees(a)kernel.org> To: Jonathan Corbet <corbet(a)lwn.net> To: Shuah Khan <shuah(a)kernel.org> To: Jann Horn <jannh(a)google.com> To: Conor Dooley <conor+dt(a)kernel.org> To: Miguel Ojeda <ojeda(a)kernel.org> To: Alex Gaynor <alex.gaynor(a)gmail.com> To: Boqun Feng <boqun.feng(a)gmail.com> To: Gary Guo <gary(a)garyguo.net> To: Björn Roy Baron <bjorn3_gh(a)protonmail.com> To: Benno Lossin <benno.lossin(a)proton.me> To: Andreas Hindborg <a.hindborg(a)kernel.org> To: Alice Ryhl <aliceryhl(a)google.com> To: Trevor Gross <tmgross(a)umich.edu> Cc: linux-kernel(a)vger.kernel.org Cc: linux-fsdevel(a)vger.kernel.org Cc: linux-mm(a)kvack.org Cc: linux-riscv(a)lists.infradead.org Cc: devicetree(a)vger.kernel.org Cc: linux-arch(a)vger.kernel.org Cc: linux-doc(a)vger.kernel.org Cc: linux-kselftest(a)vger.kernel.org Cc: alistair.francis(a)wdc.com Cc: richard.henderson(a)linaro.org Cc: jim.shu(a)sifive.com Cc: andybnac(a)gmail.com Cc: kito.cheng(a)sifive.com Cc: charlie(a)rivosinc.com Cc: atishp(a)rivosinc.com Cc: evan(a)rivosinc.com Cc: cleger(a)rivosinc.com Cc: alexghiti(a)rivosinc.com Cc: samitolvanen(a)google.com Cc: broonie(a)kernel.org Cc: rick.p.edgecombe(a)intel.com Cc: rust-for-linux(a)vger.kernel.org changelog --------- v19: - riscv_nousercfi was `int`. changed it to unsigned long. Thanks to Alex Ghiti for reporting it. It was a bug. - ELP is cleared on trap entry only when CONFIG_64BIT. - restore ssp back on return to usermode was being done before `riscv_v_context_nesting_end` on trap exit path. If kernel shadow stack were enabled this would result in kernel operating on user shadow stack and panic (as I found in my testing of kcfi patch series). So fixed that. v18: - rebased on 6.16-rc1 - uprobe handling clears ELP in sstatus image in pt_regs - vdso was missing shadow stack elf note for object files. added that. Additional asm file for vdso needed the elf marker flag. toolchain should complain if `-fcf-protection=full` and marker is missing for object generated from asm file. Asked toolchain folks to fix this. Although no reason to gate the merge on that. - Split up compile options for march and fcf-protection in vdso Makefile - CONFIG_RISCV_USER_CFI option is moved under "Kernel features" menu Added `arch/riscv/configs/hardening.config` fragment which selects CONFIG_RISCV_USER_CFI v17: - fixed warnings due to empty macros in usercfi.h (reported by alexg) - fixed prefixes in commit titles reported by alexg - took below uprobe with fcfi v2 patch from Zong Li and squashed it with "riscv/traps: Introduce software check exception and uprobe handling" https://lore.kernel.org/all/20250604093403.10916-1-zong.li@sifive.com/ v16: - If FWFT is not implemented or returns error for shadow stack activation, then no_usercfi is set to disable shadow stack. Although this should be picked up by extension validation and activation. Fixed this bug for zicfilp and zicfiss both. Thanks to Charlie Jenkins for reporting this. - If toolchain doesn't support cfi, cfi kselftest shouldn't build. Suggested by Charlie Jenkins. - Default for CONFIG_RISCV_USER_CFI is set to no. Charlie/Atish suggested to keep it off till we have more hardware availibility with RVA23 profile and zimop/zcmop implemented. Else this will start breaking people's workflow - Includes the fix if "!RV64 and !SBI" then definitions for FWFT in asm-offsets.c error. v15: - Toolchain has been updated to include `-fcf-protection` flag. This exists for x86 as well. Updated kernel patches to compile vDSO and selftest to compile with `fcf-protection=full` flag. - selecting CONFIG_RISCV_USERCFI selects CONFIG_RISCV_SBI. - Patch to enable shadow stack for kernel wasn't hidden behind CONFIG_RISCV_USERCFI and CONFIG_RISCV_SBI. fixed that. v14: - rebased on top of palmer/sbi-v3. Thus dropped clement's FWFT patches Updated RISCV_ISA_EXT_XXXX in hwcap and hwprobe constants. - Took Radim's suggestions on bitfields. - Placed cfi_state at the end of thread_info block so that current situation is not disturbed with respect to member fields of thread_info in single cacheline. v13: - cpu_supports_shadow_stack/cpu_supports_indirect_br_lp_instr uses riscv_has_extension_unlikely() - uses nops(count) to create nop slide - RISCV_ACQUIRE_BARRIER is not needed in `amo_user_shstk`. Removed it - changed ternaries to simply use implicit casting to convert to bool. - kernel command line allows to disable zicfilp and zicfiss independently. updated kernel-parameters.txt. - ptrace user abi for cfi uses bitmasks instead of bitfields. Added ptrace kselftest. - cosmetic and grammatical changes to documentation. v12: - It seems like I had accidently squashed arch agnostic indirect branch tracking prctl and riscv implementation of those prctls. Split them again. - set_shstk_status/set_indir_lp_status perform CSR writes only when CPU support is available. As suggested by Zong Li. - Some minor clean up in kselftests as suggested by Zong Li. v11: - patch "arch/riscv: compile vdso with landing pad" was unconditionally selecting `_zicfilp` for vDSO compile. fixed that. Changed `lpad 1` to to `lpad 0`. v10: - dropped "mm: helper `is_shadow_stack_vma` to check shadow stack vma". This patch is not that interesting to this patch series for risc-v. There are instances in arch directories where VM_SHADOW_STACK flag is anyways used. Dropping this patch to expedite merging in riscv tree. - Took suggestions from `Clement` on "riscv: zicfiss / zicfilp enumeration" to validate presence of cfi based on config. - Added a patch for vDSO to have `lpad 0`. I had omitted this earlier to make sure we add single vdso object with cfi enabled. But a vdso object with scheme of zero labeled landing pad is least common denominator and should work with all objects of zero labeled as well as function-signature labeled objects. v9: - rebased on master (39a803b754d5 fix braino in "9p: fix ->rename_sem exclusion") - dropped "mm: Introduce ARCH_HAS_USER_SHADOW_STACK" (master has it from arm64/gcs) - dropped "prctl: arch-agnostic prctl for shadow stack" (master has it from arm64/gcs) v8: - rebased on palmer/for-next - dropped samuel holland's `envcfg` context switch patches. they are in parlmer/for-next v7: - Removed "riscv/Kconfig: enable HAVE_EXIT_THREAD for riscv" Instead using `deactivate_mm` flow to clean up. see here for more context https://lore.kernel.org/all/20230908203655.543765-1-rick.p.edgecombe@intel.… - Changed the header include in `kselftest`. Hopefully this fixes compile issue faced by Zong Li at SiFive. - Cleaned up an orphaned change to `mm/mmap.c` in below patch "riscv/mm : ensure PROT_WRITE leads to VM_READ | VM_WRITE" - Lock interfaces for shadow stack and indirect branch tracking expect arg == 0 Any future evolution of this interface should accordingly define how arg should be setup. - `mm/map.c` has an instance of using `VM_SHADOW_STACK`. Fixed it to use helper `is_shadow_stack_vma`. - Link to v6: https://lore.kernel.org/r/20241008-v5_user_cfi_series-v6-0-60d9fe073f37@riv… v6: - Picked up Samuel Holland's changes as is with `envcfg` placed in `thread` instead of `thread_info` - fixed unaligned newline escapes in kselftest - cleaned up messages in kselftest and included test output in commit message - fixed a bug in clone path reported by Zong Li - fixed a build issue if CONFIG_RISCV_ISA_V is not selected (this was introduced due to re-factoring signal context management code) v5: - rebased on v6.12-rc1 - Fixed schema related issues in device tree file - Fixed some of the documentation related issues in zicfilp/ss.rst (style issues and added index) - added `SHADOW_STACK_SET_MARKER` so that implementation can define base of shadow stack. - Fixed warnings on definitions added in usercfi.h when CONFIG_RISCV_USER_CFI is not selected. - Adopted context header based signal handling as proposed by Andy Chiu - Added support for enabling kernel mode access to shadow stack using FWFT (https://github.com/riscv-non-isa/riscv-sbi-doc/blob/master/src/ext-firmware…) - Link to v5: https://lore.kernel.org/r/20241001-v5_user_cfi_series-v1-0-3ba65b6e550f@riv… (Note: I had an issue in my workflow due to which version number wasn't picked up correctly while sending out patches) v4: - rebased on 6.11-rc6 - envcfg: Converged with Samuel Holland's patches for envcfg management on per- thread basis. - vma_is_shadow_stack is renamed to is_vma_shadow_stack - picked up Mark Brown's `ARCH_HAS_USER_SHADOW_STACK` patch - signal context: using extended context management to maintain compatibility. - fixed `-Wmissing-prototypes` compiler warnings for prctl functions - Documentation fixes and amending typos. - Link to v4: https://lore.kernel.org/all/20240912231650.3740732-1-debug@rivosinc.com/ v3: - envcfg logic to pick up base envcfg had a bug where `ENVCFG_CBZE` could have been picked on per task basis, even though CPU didn't implement it. Fixed in this series. - dt-bindings As suggested, split into separate commit. fixed the messaging that spec is in public review - arch_is_shadow_stack change arch_is_shadow_stack changed to vma_is_shadow_stack - hwprobe zicfiss / zicfilp if present will get enumerated in hwprobe - selftests As suggested, added object and binary filenames to .gitignore Selftest binary anyways need to be compiled with cfi enabled compiler which will make sure that landing pad and shadow stack are enabled. Thus removed separate enable/disable tests. Cleaned up tests a bit. - Link to v3: https://lore.kernel.org/lkml/20240403234054.2020347-1-debug@rivosinc.com/ v2: - Using config `CONFIG_RISCV_USER_CFI`, kernel support for riscv control flow integrity for user mode programs can be compiled in the kernel. - Enabling of control flow integrity for user programs is left to user runtime - This patch series introduces arch agnostic `prctls` to enable shadow stack and indirect branch tracking. And implements them on riscv. --- Changes in v19: - Link to v18: https://lore.kernel.org/r/20250711-v5_user_cfi_series-v18-0-a8ee62f9f38e@ri… Changes in v18: - Link to v17: https://lore.kernel.org/r/20250604-v5_user_cfi_series-v17-0-4565c2cf869f@ri… Changes in v17: - Link to v16: https://lore.kernel.org/r/20250522-v5_user_cfi_series-v16-0-64f61a35eee7@ri… Changes in v16: - Link to v15: https://lore.kernel.org/r/20250502-v5_user_cfi_series-v15-0-914966471885@ri… Changes in v15: - changelog posted just below cover letter - Link to v14: https://lore.kernel.org/r/20250429-v5_user_cfi_series-v14-0-5239410d012a@ri… Changes in v14: - changelog posted just below cover letter - Link to v13: https://lore.kernel.org/r/20250424-v5_user_cfi_series-v13-0-971437de586a@ri… Changes in v13: - changelog posted just below cover letter - Link to v12: https://lore.kernel.org/r/20250314-v5_user_cfi_series-v12-0-e51202b53138@ri… Changes in v12: - changelog posted just below cover letter - Link to v11: https://lore.kernel.org/r/20250310-v5_user_cfi_series-v11-0-86b36cbfb910@ri… Changes in v11: - changelog posted just below cover letter - Link to v10: https://lore.kernel.org/r/20250210-v5_user_cfi_series-v10-0-163dcfa31c60@ri… --- Andy Chiu (1): riscv: signal: abstract header saving for setup_sigcontext Deepak Gupta (25): mm: VM_SHADOW_STACK definition for riscv dt-bindings: riscv: zicfilp and zicfiss in dt-bindings (extensions.yaml) riscv: zicfiss / zicfilp enumeration riscv: zicfiss / zicfilp extension csr and bit definitions riscv: usercfi state for task and save/restore of CSR_SSP on trap entry/exit riscv/mm : ensure PROT_WRITE leads to VM_READ | VM_WRITE riscv/mm: manufacture shadow stack pte riscv/mm: teach pte_mkwrite to manufacture shadow stack PTEs riscv/mm: write protect and shadow stack riscv/mm: Implement map_shadow_stack() syscall riscv/shstk: If needed allocate a new shadow stack on clone riscv: Implements arch agnostic shadow stack prctls prctl: arch-agnostic prctl for indirect branch tracking riscv: Implements arch agnostic indirect branch tracking prctls riscv/traps: Introduce software check exception and uprobe handling riscv/signal: save and restore of shadow stack for signal riscv/kernel: update __show_regs to print shadow stack register riscv/ptrace: riscv cfi status and state via ptrace and in core files riscv/hwprobe: zicfilp / zicfiss enumeration in hwprobe riscv: kernel command line option to opt out of user cfi riscv: enable kernel access to shadow stack memory via FWFT sbi call riscv: create a config for shadow stack and landing pad instr support riscv: Documentation for landing pad / indirect branch tracking riscv: Documentation for shadow stack on riscv kselftest/riscv: kselftest for user mode cfi Jim Shu (1): arch/riscv: compile vdso with landing pad and shadow stack note Documentation/admin-guide/kernel-parameters.txt | 8 + Documentation/arch/riscv/index.rst | 2 + Documentation/arch/riscv/zicfilp.rst | 115 +++++ Documentation/arch/riscv/zicfiss.rst | 179 +++++++ .../devicetree/bindings/riscv/extensions.yaml | 14 + arch/riscv/Kconfig | 21 + arch/riscv/Makefile | 5 +- arch/riscv/configs/hardening.config | 4 + arch/riscv/include/asm/asm-prototypes.h | 1 + arch/riscv/include/asm/assembler.h | 44 ++ arch/riscv/include/asm/cpufeature.h | 12 + arch/riscv/include/asm/csr.h | 16 + arch/riscv/include/asm/entry-common.h | 2 + arch/riscv/include/asm/hwcap.h | 2 + arch/riscv/include/asm/mman.h | 26 + arch/riscv/include/asm/mmu_context.h | 7 + arch/riscv/include/asm/pgtable.h | 30 +- arch/riscv/include/asm/processor.h | 1 + arch/riscv/include/asm/thread_info.h | 3 + arch/riscv/include/asm/usercfi.h | 95 ++++ arch/riscv/include/asm/vector.h | 3 + arch/riscv/include/uapi/asm/hwprobe.h | 2 + arch/riscv/include/uapi/asm/ptrace.h | 34 ++ arch/riscv/include/uapi/asm/sigcontext.h | 1 + arch/riscv/kernel/Makefile | 1 + arch/riscv/kernel/asm-offsets.c | 10 + arch/riscv/kernel/cpufeature.c | 27 + arch/riscv/kernel/entry.S | 38 ++ arch/riscv/kernel/head.S | 27 + arch/riscv/kernel/process.c | 27 +- arch/riscv/kernel/ptrace.c | 95 ++++ arch/riscv/kernel/signal.c | 148 +++++- arch/riscv/kernel/sys_hwprobe.c | 2 + arch/riscv/kernel/sys_riscv.c | 10 + arch/riscv/kernel/traps.c | 54 ++ arch/riscv/kernel/usercfi.c | 545 +++++++++++++++++++++ arch/riscv/kernel/vdso/Makefile | 11 +- arch/riscv/kernel/vdso/flush_icache.S | 4 + arch/riscv/kernel/vdso/getcpu.S | 4 + arch/riscv/kernel/vdso/rt_sigreturn.S | 4 + arch/riscv/kernel/vdso/sys_hwprobe.S | 4 + arch/riscv/kernel/vdso/vgetrandom-chacha.S | 5 +- arch/riscv/mm/init.c | 2 +- arch/riscv/mm/pgtable.c | 16 + include/linux/cpu.h | 4 + include/linux/mm.h | 7 + include/uapi/linux/elf.h | 2 + include/uapi/linux/prctl.h | 27 + kernel/sys.c | 30 ++ tools/testing/selftests/riscv/Makefile | 2 +- tools/testing/selftests/riscv/cfi/.gitignore | 3 + tools/testing/selftests/riscv/cfi/Makefile | 16 + tools/testing/selftests/riscv/cfi/cfi_rv_test.h | 82 ++++ tools/testing/selftests/riscv/cfi/riscv_cfi_test.c | 173 +++++++ tools/testing/selftests/riscv/cfi/shadowstack.c | 385 +++++++++++++++ tools/testing/selftests/riscv/cfi/shadowstack.h | 27 + 56 files changed, 2389 insertions(+), 30 deletions(-) --- base-commit: a2a05801de77ca5122fc34e3eb84d6359ef70389 change-id: 20240930-v5_user_cfi_series-3dc332f8f5b2 -- - 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[PATCH kvm-next V11 0/7] Add NUMA mempolicy support for KVM guest-memfd

by Shivank Garg

This series introduces NUMA-aware memory placement support for KVM guests with guest_memfd memory backends. It builds upon Fuad Tabba's work (V17) that enabled host-mapping for guest_memfd memory [1] and can be applied directly applied on KVM tree [2] (branch kvm-next, base commit: a6ad5413, Merge branch 'guest-memfd-mmap' into HEAD) == Background == KVM's guest-memfd memory backend currently lacks support for NUMA policy enforcement, causing guest memory allocations to be distributed across host nodes according to kernel's default behavior, irrespective of any policy specified by the VMM. This limitation arises because conventional userspace NUMA control mechanisms like mbind(2) don't work since the memory isn't directly mapped to userspace when allocations occur. Fuad's work [1] provides the necessary mmap capability, and this series leverages it to enable mbind(2). == Implementation == This series implements proper NUMA policy support for guest-memfd by: 1. Adding mempolicy-aware allocation APIs to the filemap layer. 2. Introducing custom inodes (via a dedicated slab-allocated inode cache, kvm_gmem_inode_info) to store NUMA policy and metadata for guest memory. 3. Implementing get/set_policy vm_ops in guest_memfd to support NUMA policy. With these changes, VMMs can now control guest memory placement by mapping guest_memfd file descriptor and using mbind(2) to specify: - Policy modes: default, bind, interleave, or preferred - Host NUMA nodes: List of target nodes for memory allocation These Policies affect only future allocations and do not migrate existing memory. This matches mbind(2)'s default behavior which affects only new allocations unless overridden with MPOL_MF_MOVE/MPOL_MF_MOVE_ALL flags (Not supported for guest_memfd as it is unmovable by design). == Upstream Plan == Phased approach as per David's guest_memfd extension overview [3] and community calls [4]: Phase 1 (this series): 1. Focuses on shared guest_memfd support (non-CoCo VMs). 2. Builds on Fuad's host-mapping work [1]. Phase2 (future work): 1. NUMA support for private guest_memfd (CoCo VMs). 2. Depends on SNP in-place conversion support [5]. This series provides a clean integration path for NUMA-aware memory management for guest_memfd and lays the groundwork for future confidential computing NUMA capabilities. Thanks, Shivank == Changelog == - v1,v2: Extended the KVM_CREATE_GUEST_MEMFD IOCTL to pass mempolicy. - v3: Introduced fbind() syscall for VMM memory-placement configuration. - v4-v6: Current approach using shared_policy support and vm_ops (based on suggestions from David [6] and guest_memfd bi-weekly upstream call discussion [7]). - v7: Use inodes to store NUMA policy instead of file [8]. - v8: Rebase on top of Fuad's V12: Host mmaping for guest_memfd memory. - v9: Rebase on top of Fuad's V13 and incorporate review comments - V10: Rebase on top of Fuad's V17. Use latest guest_memfd inode patch from Ackerley (with David's review comments). Use newer kmem_cache_create() API variant with arg parameter (Vlastimil) - V11: Rebase on kvm-next, remove RFC tag, use Ackerley's latest patch and fix a rcu race bug during kvm module unload. [1] https://lore.kernel.org/all/20250729225455.670324-1-seanjc@google.com [2] https://git.kernel.org/pub/scm/virt/kvm/kvm.git/log/?h=next [3] https://lore.kernel.org/all/c1c9591d-218a-495c-957b-ba356c8f8e09@redhat.com [4] https://docs.google.com/document/d/1M6766BzdY1Lhk7LiR5IqVR8B8mG3cr-cxTxOrAo… [5] https://lore.kernel.org/all/20250613005400.3694904-1-michael.roth@amd.com [6] https://lore.kernel.org/all/6fbef654-36e2-4be5-906e-2a648a845278@redhat.com [7] https://lore.kernel.org/all/2b77e055-98ac-43a1-a7ad-9f9065d7f38f@amd.com [8] https://lore.kernel.org/all/diqzbjumm167.fsf@ackerleytng-ctop.c.googlers.com Ackerley Tng (1): KVM: guest_memfd: Use guest mem inodes instead of anonymous inodes Matthew Wilcox (Oracle) (2): mm/filemap: Add NUMA mempolicy support to filemap_alloc_folio() mm/filemap: Extend __filemap_get_folio() to support NUMA memory policies Shivank Garg (4): mm/mempolicy: Export memory policy symbols KVM: guest_memfd: Add slab-allocated inode cache KVM: guest_memfd: Enforce NUMA mempolicy using shared policy KVM: guest_memfd: selftests: Add tests for mmap and NUMA policy support fs/bcachefs/fs-io-buffered.c | 2 +- fs/btrfs/compression.c | 4 +- fs/btrfs/verity.c | 2 +- fs/erofs/zdata.c | 2 +- fs/f2fs/compress.c | 2 +- include/linux/pagemap.h | 18 +- include/uapi/linux/magic.h | 1 + mm/filemap.c | 23 +- mm/mempolicy.c | 6 + mm/readahead.c | 2 +- tools/testing/selftests/kvm/Makefile.kvm | 1 + .../testing/selftests/kvm/guest_memfd_test.c | 121 ++++++++ virt/kvm/guest_memfd.c | 262 ++++++++++++++++-- virt/kvm/kvm_main.c | 7 +- virt/kvm/kvm_mm.h | 9 +- 15 files changed, 412 insertions(+), 50 deletions(-) -- 2.43.0 --- == Earlier Postings == v10: https://lore.kernel.org/all/20250811090605.16057-2-shivankg@amd.com v9: https://lore.kernel.org/all/20250713174339.13981-2-shivankg@amd.com v8: https://lore.kernel.org/all/20250618112935.7629-1-shivankg@amd.com v7: https://lore.kernel.org/all/20250408112402.181574-1-shivankg@amd.com v6: https://lore.kernel.org/all/20250226082549.6034-1-shivankg@amd.com v5: https://lore.kernel.org/all/20250219101559.414878-1-shivankg@amd.com v4: https://lore.kernel.org/all/20250210063227.41125-1-shivankg@amd.com v3: https://lore.kernel.org/all/20241105164549.154700-1-shivankg@amd.com v2: https://lore.kernel.org/all/20240919094438.10987-1-shivankg@amd.com v1: https://lore.kernel.org/all/20240916165743.201087-1-shivankg@amd.com

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