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[PATCH v7 00/12] Direct Map Removal Support for guest_memfd

by Patrick Roy

From: Patrick Roy <roypat(a)amazon.co.uk> [ based on kvm/next ] Unmapping virtual machine guest memory from the host kernel's direct map is a successful mitigation against Spectre-style transient execution issues: If the kernel page tables do not contain entries pointing to guest memory, then any attempted speculative read through the direct map will necessarily be blocked by the MMU before any observable microarchitectural side-effects happen. This means that Spectre-gadgets and similar cannot be used to target virtual machine memory. Roughly 60% of speculative execution issues fall into this category [1, Table 1]. This patch series extends guest_memfd with the ability to remove its memory from the host kernel's direct map, to be able to attain the above protection for KVM guests running inside guest_memfd. Additionally, a Firecracker branch with support for these VMs can be found on GitHub [2]. For more details, please refer to the v5 cover letter [v5]. No substantial changes in design have taken place since. === Changes Since v6 === - Drop patch for passing struct address_space to ->free_folio(), due to possible races with freeing of the address_space. (Hugh) - Stop using PG_uptodate / gmem preparedness tracking to keep track of direct map state. Instead, use the lowest bit of folio->private. (Mike, David) - Do direct map removal when establishing mapping of gmem folio instead of at allocation time, due to impossibility of handling direct map removal errors in kvm_gmem_populate(). (Patrick) - Do TLB flushes after direct map removal, and provide a module parameter to opt out from them, and a new patch to export flush_tlb_kernel_range() to KVM. (Will) [1]: https://download.vusec.net/papers/quarantine_raid23.pdf [2]: https://github.com/firecracker-microvm/firecracker/tree/feature/secret-hidi… [RFCv1]: https://lore.kernel.org/kvm/20240709132041.3625501-1-roypat@amazon.co.uk/ [RFCv2]: https://lore.kernel.org/kvm/20240910163038.1298452-1-roypat@amazon.co.uk/ [RFCv3]: https://lore.kernel.org/kvm/20241030134912.515725-1-roypat@amazon.co.uk/ [v4]: https://lore.kernel.org/kvm/20250221160728.1584559-1-roypat@amazon.co.uk/ [v5]: https://lore.kernel.org/kvm/20250828093902.2719-1-roypat@amazon.co.uk/ [v6]: https://lore.kernel.org/kvm/20250912091708.17502-1-roypat@amazon.co.uk/ Patrick Roy (12): arch: export set_direct_map_valid_noflush to KVM module x86/tlb: export flush_tlb_kernel_range to KVM module mm: introduce AS_NO_DIRECT_MAP KVM: guest_memfd: Add stub for kvm_arch_gmem_invalidate KVM: guest_memfd: Add flag to remove from direct map KVM: guest_memfd: add module param for disabling TLB flushing KVM: selftests: load elf via bounce buffer KVM: selftests: set KVM_MEM_GUEST_MEMFD in vm_mem_add() if guest_memfd != -1 KVM: selftests: Add guest_memfd based vm_mem_backing_src_types KVM: selftests: cover GUEST_MEMFD_FLAG_NO_DIRECT_MAP in existing selftests KVM: selftests: stuff vm_mem_backing_src_type into vm_shape KVM: selftests: Test guest execution from direct map removed gmem Documentation/virt/kvm/api.rst | 5 ++ arch/arm64/include/asm/kvm_host.h | 12 ++++ arch/arm64/mm/pageattr.c | 1 + arch/loongarch/mm/pageattr.c | 1 + arch/riscv/mm/pageattr.c | 1 + arch/s390/mm/pageattr.c | 1 + arch/x86/include/asm/tlbflush.h | 3 +- arch/x86/mm/pat/set_memory.c | 1 + arch/x86/mm/tlb.c | 1 + include/linux/kvm_host.h | 9 +++ include/linux/pagemap.h | 16 +++++ include/linux/secretmem.h | 18 ----- include/uapi/linux/kvm.h | 2 + lib/buildid.c | 4 +- mm/gup.c | 19 ++---- mm/mlock.c | 2 +- mm/secretmem.c | 8 +-- .../testing/selftests/kvm/guest_memfd_test.c | 2 + .../testing/selftests/kvm/include/kvm_util.h | 37 ++++++++--- .../testing/selftests/kvm/include/test_util.h | 8 +++ tools/testing/selftests/kvm/lib/elf.c | 8 +-- tools/testing/selftests/kvm/lib/io.c | 23 +++++++ tools/testing/selftests/kvm/lib/kvm_util.c | 61 +++++++++-------- tools/testing/selftests/kvm/lib/test_util.c | 8 +++ tools/testing/selftests/kvm/lib/x86/sev.c | 1 + .../selftests/kvm/pre_fault_memory_test.c | 1 + .../selftests/kvm/set_memory_region_test.c | 50 ++++++++++++-- .../kvm/x86/private_mem_conversions_test.c | 7 +- virt/kvm/guest_memfd.c | 66 +++++++++++++++++-- virt/kvm/kvm_main.c | 8 +++ 30 files changed, 290 insertions(+), 94 deletions(-) base-commit: a6ad54137af92535cfe32e19e5f3bc1bb7dbd383 -- 2.51.0

2 weeks, 3 days

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[PATCH v2] selftest/mm: fix pointer comparison in mremap_test

by Ankit Khushwaha

Pointer arthemitic with 'void * addr' and 'ulong dest_alignment' triggers following warning: mremap_test.c:1035:31: warning: pointer comparison always evaluates to false [-Wtautological-compare] 1035 | if (addr + c.dest_alignment < addr) { | ^ this warning is raised from clang version 20.1.8 (Fedora 20.1.8-4.fc42). use 'void *tmp_addr' to do the pointer arthemitic. Signed-off-by: Ankit Khushwaha <ankitkhushwaha.linux(a)gmail.com> --- Changelog: v2: - use 'void *tmp_addr' for pointer arthemitic instead of typecasting 'addr' to 'unsigned long long' as suggested by Andrew. v1: https://lore.kernel.org/linux-kselftest/20251106104917.39890-1-ankitkhushwa… --- tools/testing/selftests/mm/mremap_test.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/mm/mremap_test.c b/tools/testing/selftests/mm/mremap_test.c index a95c0663a011..308576437228 100644 --- a/tools/testing/selftests/mm/mremap_test.c +++ b/tools/testing/selftests/mm/mremap_test.c @@ -994,7 +994,7 @@ static void mremap_move_multi_invalid_vmas(FILE *maps_fp, unsigned long page_siz static long long remap_region(struct config c, unsigned int threshold_mb, char *rand_addr) { - void *addr, *src_addr, *dest_addr, *dest_preamble_addr = NULL; + void *addr, *tmp_addr, *src_addr, *dest_addr, *dest_preamble_addr = NULL; unsigned long long t, d; struct timespec t_start = {0, 0}, t_end = {0, 0}; long long start_ns, end_ns, align_mask, ret, offset; @@ -1032,7 +1032,8 @@ static long long remap_region(struct config c, unsigned int threshold_mb, /* Don't destroy existing mappings unless expected to overlap */ while (!is_remap_region_valid(addr, c.region_size) && !c.overlapping) { /* Check for unsigned overflow */ - if (addr + c.dest_alignment < addr) { + tmp_addr = addr + c.dest_alignment; + if (tmp_addr < addr) { ksft_print_msg("Couldn't find a valid region to remap to\n"); ret = -1; goto clean_up_src; -- 2.51.1

2 weeks, 3 days

3
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[PATCH net-next 0/3] Add YNL test framework and library improvements

by Hangbin Liu

This series enhances YNL tools with some functionalities and adds YNL selftest framework. Changes include: - Add MAC address parsing support in YNL library - Fix rt-rule spec consistency with other rt-* families - Add selftests covering CLI and ethtool functionality The tests provide usage examples and regression testing for YNL tools. Hangbin Liu (3): tools: ynl: Add MAC address parsing support netlink: specs: update rt-rule src/dst attribute types to support IPv4 addresses selftests: net: add YNL test framework Documentation/netlink/specs/rt-rule.yaml | 6 +- tools/net/ynl/pyynl/lib/ynl.py | 9 + tools/testing/selftests/Makefile | 1 + tools/testing/selftests/net/ynl/Makefile | 18 ++ tools/testing/selftests/net/ynl/cli.sh | 234 +++++++++++++++++++++ tools/testing/selftests/net/ynl/config | 6 + tools/testing/selftests/net/ynl/ethtool.sh | 188 +++++++++++++++++ tools/testing/selftests/net/ynl/settings | 1 + 8 files changed, 461 insertions(+), 2 deletions(-) create mode 100644 tools/testing/selftests/net/ynl/Makefile create mode 100755 tools/testing/selftests/net/ynl/cli.sh create mode 100644 tools/testing/selftests/net/ynl/config create mode 100755 tools/testing/selftests/net/ynl/ethtool.sh create mode 100644 tools/testing/selftests/net/ynl/settings -- 2.50.1

2 weeks, 4 days

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[PATCH] tools/nolibc: add support for fchdir()

by Thomas Weißschuh

Add support for the file descriptor based variant of chdir(). Signed-off-by: Thomas Weißschuh <thomas.weissschuh(a)linutronix.de> --- tools/include/nolibc/sys.h | 13 +++++++++++++ tools/testing/selftests/nolibc/nolibc-test.c | 2 ++ 2 files changed, 15 insertions(+) diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h index c5564f57deec88b8aa70291fcf6f9ca4dbc1d03f..a4b0fdb9b641230174f5e62d62762f59af81a00e 100644 --- a/tools/include/nolibc/sys.h +++ b/tools/include/nolibc/sys.h @@ -118,6 +118,7 @@ void *sbrk(intptr_t inc) /* * int chdir(const char *path); + * int fchdir(int fildes); */ static __attribute__((unused)) @@ -132,6 +133,18 @@ int chdir(const char *path) return __sysret(sys_chdir(path)); } +static __attribute__((unused)) +int sys_fchdir(int fildes) +{ + return my_syscall1(__NR_fchdir, fildes); +} + +static __attribute__((unused)) +int fchdir(int fildes) +{ + return __sysret(sys_fchdir(fildes)); +} + /* * int chmod(const char *path, mode_t mode); diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c index 29de21595fc95341c2aa975375a8d471cb3933fc..5927a84466cc0ede3b99611e134a8c6b8ab91e72 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -1343,6 +1343,8 @@ int run_syscall(int min, int max) CASE_TEST(dup3_0); tmp = dup3(0, 100, 0); EXPECT_SYSNE(1, tmp, -1); close(tmp); break; CASE_TEST(dup3_m1); tmp = dup3(-1, 100, 0); EXPECT_SYSER(1, tmp, -1, EBADF); if (tmp != -1) close(tmp); break; CASE_TEST(execve_root); EXPECT_SYSER(1, execve("/", (char*[]){ [0] = "/", [1] = NULL }, NULL), -1, EACCES); break; + CASE_TEST(fchdir_stdin); EXPECT_SYSER(1, fchdir(STDIN_FILENO), -1, ENOTDIR); break; + CASE_TEST(fchdir_badfd); EXPECT_SYSER(1, fchdir(-1), -1, EBADF); break; CASE_TEST(file_stream); EXPECT_SYSZR(1, test_file_stream()); break; CASE_TEST(fork); EXPECT_SYSZR(1, test_fork(FORK_STANDARD)); break; CASE_TEST(getdents64_root); EXPECT_SYSNE(1, test_getdents64("/"), -1); break; --- base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787 change-id: 20251107-nolibc-fchdir-2645c298a538 Best regards, -- Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>

2 weeks, 5 days

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[PATCH net-next v3 0/5] psp: track stats from core and provide a driver stats api

by Daniel Zahka

This series introduces stats counters for psp. Device key rotations, and so called 'stale-events' are common to all drivers and are tracked by the core. A driver facing api is provided for reporting stats required by the "Implementation Requirements" section of the PSP Architecture Specification. Drivers must implement these stats. Lastly, implementations of the driver stats api for mlx5 and netdevsim are included. Here is the output of running the psp selftest suite and then printing out stats with the ynl cli on system with a psp-capable CX7: $ ./ksft-psp-stats/drivers/net/psp.py TAP version 13 1..28 ok 1 psp.test_case # SKIP Test requires IPv4 connectivity ok 2 psp.data_basic_send_v0_ip6 ok 3 psp.test_case # SKIP Test requires IPv4 connectivity ok 4 psp.data_basic_send_v1_ip6 ok 5 psp.test_case # SKIP Test requires IPv4 connectivity ok 6 psp.data_basic_send_v2_ip6 # SKIP ('PSP version not supported', 'hdr0-aes-gmac-128') ok 7 psp.test_case # SKIP Test requires IPv4 connectivity ok 8 psp.data_basic_send_v3_ip6 # SKIP ('PSP version not supported', 'hdr0-aes-gmac-256') ok 9 psp.test_case # SKIP Test requires IPv4 connectivity ok 10 psp.data_mss_adjust_ip6 ok 11 psp.dev_list_devices ok 12 psp.dev_get_device ok 13 psp.dev_get_device_bad ok 14 psp.dev_rotate ok 15 psp.dev_rotate_spi ok 16 psp.assoc_basic ok 17 psp.assoc_bad_dev ok 18 psp.assoc_sk_only_conn ok 19 psp.assoc_sk_only_mismatch ok 20 psp.assoc_sk_only_mismatch_tx ok 21 psp.assoc_sk_only_unconn ok 22 psp.assoc_version_mismatch ok 23 psp.assoc_twice ok 24 psp.data_send_bad_key ok 25 psp.data_send_disconnect ok 26 psp.data_stale_key ok 27 psp.removal_device_rx # XFAIL Test only works on netdevsim ok 28 psp.removal_device_bi # XFAIL Test only works on netdevsim # Totals: pass:19 fail:0 xfail:2 xpass:0 skip:7 error:0 # # Responder logs (0): # STDERR: # Set PSP enable on device 1 to 0x3 # Set PSP enable on device 1 to 0x0 $ cd ynl/ $ ./pyynl/cli.py --spec netlink/specs/psp.yaml --dump get-stats [{'dev-id': 1, 'key-rotations': 5, 'rx-auth-fail': 21, 'rx-bad': 0, 'rx-bytes': 11844, 'rx-error': 0, 'rx-packets': 94, 'stale-events': 6, 'tx-bytes': 1128456, 'tx-error': 0, 'tx-packets': 780}] CHANGES: v3: - simplify error path in accel_psp_fs_init_tx() - avoid casting argument in mlx5e_accel_psp_fs_get_stats_fill() - delete unused member stats member in mlx5e_psp - remove zero length array from psp_dev_stats v2: https://lore.kernel.org/netdev/20251028000018.3869664-1-daniel.zahka@gmail.… - don't return skb->len from psp_nl_get_stats_dumpit() on success and EMSGSIZE - use %pe to print PTR_ERR() v1: https://lore.kernel.org/netdev/20251022193739.1376320-1-daniel.zahka@gmail.… Daniel Zahka (2): selftests: drv-net: psp: add assertions on core-tracked psp dev stats netdevsim: implement psp device stats Jakub Kicinski (3): psp: report basic stats from the core psp: add stats from psp spec to driver facing api net/mlx5e: Add PSP stats support for Rx/Tx flows Documentation/netlink/specs/psp.yaml | 95 +++++++ .../mellanox/mlx5/core/en_accel/psp.c | 233 ++++++++++++++++-- .../mellanox/mlx5/core/en_accel/psp.h | 16 ++ .../mellanox/mlx5/core/en_accel/psp_rxtx.c | 1 + .../net/ethernet/mellanox/mlx5/core/en_main.c | 5 + drivers/net/netdevsim/netdevsim.h | 5 + drivers/net/netdevsim/psp.c | 27 ++ include/net/psp/types.h | 32 +++ include/uapi/linux/psp.h | 18 ++ net/psp/psp-nl-gen.c | 19 ++ net/psp/psp-nl-gen.h | 2 + net/psp/psp_main.c | 3 +- net/psp/psp_nl.c | 93 +++++++ net/psp/psp_sock.c | 4 +- tools/testing/selftests/drivers/net/psp.py | 13 + 15 files changed, 549 insertions(+), 17 deletions(-) -- 2.47.3

2 weeks, 6 days

2
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[PATCH net v3] selftests: net: local_termination: Wait for interfaces to come up

by A. Sverdlin

From: Alexander Sverdlin <alexander.sverdlin(a)siemens.com> It seems that most of the tests prepare the interfaces once before the test run (setup_prepare()), rely on setup_wait() to wait for link and only then run the test(s). local_termination brings the physical interfaces down and up during test run but never wait for them to come up. If the auto-negotiation takes some seconds, first test packets are being lost, which leads to false-negative test results. Use setup_wait() in run_test() to make sure auto-negotiation has been completed after all simple_if_init() calls on physical interfaces and test packets will not be lost because of the race against link establishment. Fixes: 90b9566aa5cd3f ("selftests: forwarding: add a test for local_termination.sh") Reviewed-by: Vladimir Oltean <vladimir.oltean(a)nxp.com> Signed-off-by: Alexander Sverdlin <alexander.sverdlin(a)siemens.com> --- Changelog: v3: - moved setup_wait() from individual test groups into run_test() v2: - replaced "setup_wait_dev $h1; setup_wait_dev $h2" with setup_wait() tools/testing/selftests/net/forwarding/local_termination.sh | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/testing/selftests/net/forwarding/local_termination.sh b/tools/testing/selftests/net/forwarding/local_termination.sh index ecd34f364125c..892895659c7e4 100755 --- a/tools/testing/selftests/net/forwarding/local_termination.sh +++ b/tools/testing/selftests/net/forwarding/local_termination.sh @@ -176,6 +176,8 @@ run_test() local rcv_dmac=$(mac_get $rcv_if_name) local should_receive + setup_wait + tcpdump_start $rcv_if_name mc_route_prepare $send_if_name -- 2.51.1

2 weeks, 6 days

2
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[PATCH net-next 0/4] netconsole: Allow userdata buffer to grow dynamically

by Gustavo Luiz Duarte

The current netconsole implementation allocates a static buffer for extradata (userdata + sysdata) with a fixed size of MAX_EXTRADATA_ENTRY_LEN * MAX_EXTRADATA_ITEMS bytes for every target, regardless of whether userspace actually uses this feature. This forces us to keep MAX_EXTRADATA_ITEMS small (16), which is restrictive for users who need to attach more metadata to their log messages. This patch series enables dynamic allocation of the userdata buffer, allowing it to grow on-demand based on actual usage. The series: 1. Refactors send_fragmented_body() to simplify handling of separated userdata and sysdata (patch 1/4) 2. Splits userdata and sysdata into separate buffers (patch 2/4) 3. Implements dynamic allocation for the userdata buffer (patch 3/4) 4. Increases MAX_USERDATA_ITEMS from 16 to 256 now that we can do so without memory waste (patch 4/4) Benefits: - No memory waste when userdata is not used - Targets that use userdata only consume what they need - Users can attach significantly more metadata without impacting systems that don't use this feature Signed-off-by: Gustavo Luiz Duarte <gustavold(a)gmail.com> --- Gustavo Luiz Duarte (4): netconsole: Simplify send_fragmented_body() netconsole: Split userdata and sysdata netconsole: Dynamic allocation of userdata buffer netconsole: Increase MAX_USERDATA_ITEMS drivers/net/netconsole.c | 338 +++++++++------------ .../selftests/drivers/net/netcons_overflow.sh | 2 +- 2 files changed, 152 insertions(+), 188 deletions(-) --- base-commit: 89aec171d9d1ab168e43fcf9754b82e4c0aef9b9 change-id: 20251007-netconsole_dynamic_extradata-21bd9d726568 Best regards, -- Gustavo Duarte <gustavold(a)meta.com>

2 weeks, 6 days

2
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[PATCH] kselftest/arm64: Align zt-test register dumps

by Mark Rutland

The zt-test output is awkward to read, as the 'Expected' value isn't dumped on its own line and isn't aligned with the 'Got' value beneath. For example: Mismatch: PID=5281, iteration=3270249 Expected [00a1146901a1146902a1146903a1146904a1146905a1146906a1146907a1146908a1146909a114690aa114690ba114690ca114690da114690ea114690fa11469] Got [00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000] SVCR: 2 Add a newline, matching the other FPSIMD/SVE/SME tests, so that we get output that can be read more easily: Mismatch: PID=5281, iteration=3270249 Expected [00a1146901a1146902a1146903a1146904a1146905a1146906a1146907a1146908a1146909a114690aa114690ba114690ca114690da114690ea114690fa11469] Got [00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000] SVCR: 2 Admittedly this isn't all that important when the 'Got' value is all zeroes, but otherwise this would be a major help for identifying which portion of the 'Got' value is not as expected. Signed-off-by: Mark Rutland <mark.rutland(a)arm.com> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: Mark Brown <broonie(a)kernel.org> Cc: Shuah Khan <shuah(a)kernel.org> Cc: Will Deacon <will(a)kernel.org> Cc: linux-arm-kernel(a)lists.infradead.org Cc: linux-kselftest(a)vger.kernel.org --- tools/testing/selftests/arm64/fp/zt-test.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/arm64/fp/zt-test.S b/tools/testing/selftests/arm64/fp/zt-test.S index 38080f3c32804..a8df057716707 100644 --- a/tools/testing/selftests/arm64/fp/zt-test.S +++ b/tools/testing/selftests/arm64/fp/zt-test.S @@ -276,7 +276,7 @@ function barf bl putdec puts ", iteration=" mov x0, x22 - bl putdec + bl putdecn puts "\tExpected [" mov x0, x10 mov x1, x12 -- 2.30.2

2 weeks, 6 days

3
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[PATCH v6 0/2] KVM: guest_memfd: use write for population

by Kalyazin, Nikita

[ based on kvm/next ] Implement guest_memfd population via the write syscall. This is useful in non-CoCo use cases where the host can access guest memory. Even though the same can also be achieved via userspace mapping and memcpying from userspace, write provides a more performant option because it does not need to set page tables and it does not cause a page fault for every page like memcpy would. Note that memcpy cannot be accelerated via MADV_POPULATE_WRITE as it is not supported by guest_memfd and relies on GUP. Populating 512MiB of guest_memfd on a x86 machine: - via memcpy: 436 ms - via write: 202 ms (-54%) The write syscall support is conditional on kvm_gmem_supports_mmap. When in-place shared/private conversion is supported, write should only be allowed on shared pages. v6: - Make write support conditional on mmap support instead of relying on the up-to-date flag to decide whether writing to a page is allowed - James: Remove depenendencies on folio_test_large - James: Remove page alignment restriction - James: Formatting fixes v5: - https://lore.kernel.org/kvm/20250902111951.58315-1-kalyazin@amazon.com/ - Replace the call to the unexported filemap_remove_folio with zeroing the bytes that could not be copied - Fix checkpatch findings v4: - https://lore.kernel.org/kvm/20250828153049.3922-1-kalyazin@amazon.com - Switch from implementing the write callback to write_iter - Remove conditional compilation v3: - https://lore.kernel.org/kvm/20250303130838.28812-1-kalyazin@amazon.com - David/Mike D: Only compile support for the write syscall if CONFIG_KVM_GMEM_SHARED_MEM (now gone) is enabled. v2: - https://lore.kernel.org/kvm/20241129123929.64790-1-kalyazin@amazon.com - Switch from an ioctl to the write syscall to implement population v1: - https://lore.kernel.org/kvm/20241024095429.54052-1-kalyazin@amazon.com Nikita Kalyazin (2): KVM: guest_memfd: add generic population via write KVM: selftests: update guest_memfd write tests .../testing/selftests/kvm/guest_memfd_test.c | 51 ++++++++++++++++--- virt/kvm/guest_memfd.c | 49 ++++++++++++++++++ 2 files changed, 94 insertions(+), 6 deletions(-) base-commit: 6b36119b94d0b2bb8cea9d512017efafd461d6ac -- 2.50.1

2 weeks, 6 days

4
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[PATCH v11 0/9] support FEAT_LSUI

by Yeoreum Yun

Since Armv9.6, FEAT_LSUI supplies the load/store instructions for previleged level to access to access user memory without clearing PSTATE.PAN bit. This patchset support FEAT_LSUI and applies in futex atomic operation and user_swpX emulation where can replace from ldxr/st{l}xr pair implmentation with clearing PSTATE.PAN bit to correspondant load/store unprevileged atomic operation without clearing PSTATE.PAN bit. Patch Sequences ================ Patch #1 adds cpufeature for FEAT_LSUI Patch #2-#3 expose FEAT_LSUI to guest Patch #4 adds Kconfig for FEAT_LSUI Patch #5-#6 support futex atomic-op with FEAT_LSUI Patch #7-#9 support user_swpX emulation with FEAT_LSUI Patch History ============== from v10 to v11: - use cast instruction to emulate deprecated swpb instruction - https://lore.kernel.org/all/20251103163224.818353-1-yeoreum.yun@arm.com/ from v9 to v10: - apply FEAT_LSUI to user_swpX emulation. - add test coverage for LSUI bit in ID_AA64ISAR3_EL1 - rebase to v6.18-rc4 - https://lore.kernel.org/all/20250922102244.2068414-1-yeoreum.yun@arm.com/ from v8 to v9: - refotoring __lsui_cmpxchg64() - rebase to v6.17-rc7 - https://lore.kernel.org/all/20250917110838.917281-1-yeoreum.yun@arm.com/ from v7 to v8: - implements futex_atomic_eor() and futex_atomic_cmpxchg() with casalt with C helper. - Drop the small optimisation on ll/sc futex_atomic_set operation. - modify some commit message. - https://lore.kernel.org/all/20250816151929.197589-1-yeoreum.yun@arm.com/ from v6 to v7: - wrap FEAT_LSUI with CONFIG_AS_HAS_LSUI in cpufeature - remove unnecessary addition of indentation. - remove unnecessary mte_tco_enable()/disable() on LSUI operation. - https://lore.kernel.org/all/20250811163635.1562145-1-yeoreum.yun@arm.com/ from v5 to v6: - rebase to v6.17-rc1 - https://lore.kernel.org/all/20250722121956.1509403-1-yeoreum.yun@arm.com/ from v4 to v5: - remove futex_ll_sc.h futext_lsui and lsui.h and move them to futex.h - reorganize the patches. - https://lore.kernel.org/all/20250721083618.2743569-1-yeoreum.yun@arm.com/ from v3 to v4: - rebase to v6.16-rc7 - modify some patch's title. - https://lore.kernel.org/all/20250617183635.1266015-1-yeoreum.yun@arm.com/ from v2 to v3: - expose FEAT_LUSI to guest - add help section for LUSI Kconfig - https://lore.kernel.org/all/20250611151154.46362-1-yeoreum.yun@arm.com/ from v1 to v2: - remove empty v9.6 menu entry - locate HAS_LUSI in cpucaps in order - https://lore.kernel.org/all/20250611104916.10636-1-yeoreum.yun@arm.com/ Yeoreum Yun (9): arm64: cpufeature: add FEAT_LSUI KVM: arm64: expose FEAT_LSUI to guest KVM: arm64: kselftest: set_id_regs: add test for FEAT_LSUI arm64: Kconfig: Detect toolchain support for LSUI arm64: futex: refactor futex atomic operation arm64: futex: support futex with FEAT_LSUI arm64: separate common LSUI definitions into lsui.h arm64: armv8_deprecated: convert user_swpX to inline function arm64: armv8_deprecated: apply FEAT_LSUI for swpX emulation. arch/arm64/Kconfig | 5 + arch/arm64/include/asm/futex.h | 291 +++++++++++++++--- arch/arm64/include/asm/lsui.h | 25 ++ arch/arm64/kernel/armv8_deprecated.c | 111 +++++-- arch/arm64/kernel/cpufeature.c | 10 + arch/arm64/kvm/sys_regs.c | 3 +- arch/arm64/tools/cpucaps | 1 + .../testing/selftests/kvm/arm64/set_id_regs.c | 1 + 8 files changed, 381 insertions(+), 66 deletions(-) create mode 100644 arch/arm64/include/asm/lsui.h base-commit: 6146a0f1dfae5d37442a9ddcba012add260bceb0 -- LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}

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