The set_p4d() and set_pgd() functions (in 4-level or 5-level page table setups
respectively) assume that the root page table is actually a 8KiB allocation,
with the userspace root immediately after the kernel root page table (so that
the former can enforce NX on on all the subordinate page tables, which are
actually shared).
However, users of the kernel_ident_mapping_init() code do not give it an 8KiB
allocation for its PGD. Both swsusp_arch_resume() and acpi_mp_setup_reset()
allocate only a single 4KiB page. The kexec code on x86_64 currently gets
away with it purely by chance, because it allocates 8KiB for its "control
code page" and then actually uses the first half for the PGD, then copies the
actual trampoline code into the second half only after the identmap code has
finished scribbling over it.
Fix this by defining a _PAGE_NOPTISHADOW bit (which can use the same bit as
_PAGE_SAVED_DIRTY since one is only for the PGD/P4D root and the other is
exclusively for leaf PTEs.). This instructs __pti_set_user_pgtbl() not to
write to the userspace 'shadow' PGD.
Strictly, the _PAGE_NOPTISHADOW bit doesn't need to be written out to the
actual page tables; since __pti_set_user_pgtbl() returns the value to be
written to the kernel page table, it could be filtered out. But there seems
to be no benefit to actually doing so.
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/412c90a4df7aef077141d9f68d19cbe5602d6c6d.camel@infradead.org
Cc: stable@kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Pull x86 fixes from Borislav Petkov:
- Add a terminating zero end-element to the array describing AMD CPUs
affected by erratum 1386 so that the matching loop actually
terminates instead of going off into the weeds
- Update the boot protocol documentation to mention the fact that the
preferred address to load the kernel to is considered in the
relocatable kernel case too
- Flush the memory buffer containing the microcode patch after applying
microcode on AMD Zen1 and Zen2, to avoid unnecessary slowdowns
- Make sure the PPIN CPU feature flag is cleared on all CPUs if PPIN
has been disabled
* tag 'x86_urgent_for_v6.13_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/CPU/AMD: Terminate the erratum_1386_microcode array
x86/Documentation: Update algo in init_size description of boot protocol
x86/microcode/AMD: Flush patch buffer mapping after application
x86/mm: Carve out INVLPG inline asm for use by others
x86/cpu: Fix PPIN initialization
Pull rust trace event support from Steven Rostedt:
"Allow Rust code to have trace events
Trace events is a popular way to debug what is happening inside the
kernel or just to find out what is happening. Rust code is being added
to the Linux kernel but it currently does not support the tracing
infrastructure. Add support of trace events inside Rust code"
* tag 'trace-rust-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
rust: jump_label: skip formatting generated file
jump_label: rust: pass a mut ptr to `static_key_count`
samples: rust: fix `rust_print` build making it a combined module
rust: add arch_static_branch
jump_label: adjust inline asm to be consistent
rust: samples: add tracepoint to Rust sample
rust: add tracepoint support
rust: add static_branch_unlikely for static_key_false
Josh Poimboeuf reports that he got a "will-it-scale.per_process_ops 1.9%
improvement" report for his patch that changed __get_user() to use
pointer masking instead of the explicit speculation barrier. However,
that patch doesn't actually work in the general case, because some (very
bad) architecture-specific code actually depends on __get_user() also
working on kernel addresses.
A profile showed that the offending __get_user() was the futex code,
which really should be fixed up to not use that horrid legacy case.
Rewrite futex_get_value_locked() to use the modern user acccess helpers,
and inline it so that the compiler not only avoids the function call for
a few instructions, but can do CSE on the address masking.
It also turns out the x86 futex functions have unnecessary barriers in
other places, so let's fix those up too.
Link: https://lore.kernel.org/all/20241115230653.hfvzyf3aqqntgp63@jpoimboe/
Reported-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull kvm updates from Paolo Bonzini:
"The biggest change here is eliminating the awful idea that KVM had of
essentially guessing which pfns are refcounted pages.
The reason to do so was that KVM needs to map both non-refcounted
pages (for example BARs of VFIO devices) and VM_PFNMAP/VM_MIXMEDMAP
VMAs that contain refcounted pages.
However, the result was security issues in the past, and more recently
the inability to map VM_IO and VM_PFNMAP memory that _is_ backed by
struct page but is not refcounted. In particular this broke virtio-gpu
blob resources (which directly map host graphics buffers into the
guest as "vram" for the virtio-gpu device) with the amdgpu driver,
because amdgpu allocates non-compound higher order pages and the tail
pages could not be mapped into KVM.
This requires adjusting all uses of struct page in the
per-architecture code, to always work on the pfn whenever possible.
The large series that did this, from David Stevens and Sean
Christopherson, also cleaned up substantially the set of functions
that provided arch code with the pfn for a host virtual addresses.
The previous maze of twisty little passages, all different, is
replaced by five functions (__gfn_to_page, __kvm_faultin_pfn, the
non-__ versions of these two, and kvm_prefetch_pages) saving almost
200 lines of code.
ARM:
- Support for stage-1 permission indirection (FEAT_S1PIE) and
permission overlays (FEAT_S1POE), including nested virt + the
emulated page table walker
- Introduce PSCI SYSTEM_OFF2 support to KVM + client driver. This
call was introduced in PSCIv1.3 as a mechanism to request
hibernation, similar to the S4 state in ACPI
- Explicitly trap + hide FEAT_MPAM (QoS controls) from KVM guests. As
part of it, introduce trivial initialization of the host's MPAM
context so KVM can use the corresponding traps
- PMU support under nested virtualization, honoring the guest
hypervisor's trap configuration and event filtering when running a
nested guest
- Fixes to vgic ITS serialization where stale device/interrupt table
entries are not zeroed when the mapping is invalidated by the VM
- Avoid emulated MMIO completion if userspace has requested
synchronous external abort injection
- Various fixes and cleanups affecting pKVM, vCPU initialization, and
selftests
LoongArch:
- Add iocsr and mmio bus simulation in kernel.
- Add in-kernel interrupt controller emulation.
- Add support for virtualization extensions to the eiointc irqchip.
PPC:
- Drop lingering and utterly obsolete references to PPC970 KVM, which
was removed 10 years ago.
- Fix incorrect documentation references to non-existing ioctls
RISC-V:
- Accelerate KVM RISC-V when running as a guest
- Perf support to collect KVM guest statistics from host side
s390:
- New selftests: more ucontrol selftests and CPU model sanity checks
- Support for the gen17 CPU model
- List registers supported by KVM_GET/SET_ONE_REG in the
documentation
x86:
- Cleanup KVM's handling of Accessed and Dirty bits to dedup code,
improve documentation, harden against unexpected changes.
Even if the hardware A/D tracking is disabled, it is possible to
use the hardware-defined A/D bits to track if a PFN is Accessed
and/or Dirty, and that removes a lot of special cases.
- Elide TLB flushes when aging secondary PTEs, as has been done in
x86's primary MMU for over 10 years.
- Recover huge pages in-place in the TDP MMU when dirty page logging
is toggled off, instead of zapping them and waiting until the page
is re-accessed to create a huge mapping. This reduces vCPU jitter.
- Batch TLB flushes when dirty page logging is toggled off. This
reduces the time it takes to disable dirty logging by ~3x.
- Remove the shrinker that was (poorly) attempting to reclaim shadow
page tables in low-memory situations.
- Clean up and optimize KVM's handling of writes to
MSR_IA32_APICBASE.
- Advertise CPUIDs for new instructions in Clearwater Forest
- Quirk KVM's misguided behavior of initialized certain feature MSRs
to their maximum supported feature set, which can result in KVM
creating invalid vCPU state. E.g. initializing PERF_CAPABILITIES to
a non-zero value results in the vCPU having invalid state if
userspace hides PDCM from the guest, which in turn can lead to
save/restore failures.
- Fix KVM's handling of non-canonical checks for vCPUs that support
LA57 to better follow the "architecture", in quotes because the
actual behavior is poorly documented. E.g. most MSR writes and
descriptor table loads ignore CR4.LA57 and operate purely on
whether the CPU supports LA57.
- Bypass the register cache when querying CPL from kvm_sched_out(),
as filling the cache from IRQ context is generally unsafe; harden
the cache accessors to try to prevent similar issues from occuring
in the future. The issue that triggered this change was already
fixed in 6.12, but was still kinda latent.
- Advertise AMD_IBPB_RET to userspace, and fix a related bug where
KVM over-advertises SPEC_CTRL when trying to support cross-vendor
VMs.
- Minor cleanups
- Switch hugepage recovery thread to use vhost_task.
These kthreads can consume significant amounts of CPU time on
behalf of a VM or in response to how the VM behaves (for example
how it accesses its memory); therefore KVM tried to place the
thread in the VM's cgroups and charge the CPU time consumed by that
work to the VM's container.
However the kthreads did not process SIGSTOP/SIGCONT, and therefore
cgroups which had KVM instances inside could not complete freezing.
Fix this by replacing the kthread with a PF_USER_WORKER thread, via
the vhost_task abstraction. Another 100+ lines removed, with
generally better behavior too like having these threads properly
parented in the process tree.
- Revert a workaround for an old CPU erratum (Nehalem/Westmere) that
didn't really work; there was really nothing to work around anyway:
the broken patch was meant to fix nested virtualization, but the
PERF_GLOBAL_CTRL MSR is virtualized and therefore unaffected by the
erratum.
- Fix 6.12 regression where CONFIG_KVM will be built as a module even
if asked to be builtin, as long as neither KVM_INTEL nor KVM_AMD is
'y'.
x86 selftests:
- x86 selftests can now use AVX.
Documentation:
- Use rST internal links
- Reorganize the introduction to the API document
Generic:
- Protect vcpu->pid accesses outside of vcpu->mutex with a rwlock
instead of RCU, so that running a vCPU on a different task doesn't
encounter long due to having to wait for all CPUs become quiescent.
In general both reads and writes are rare, but userspace that
supports confidential computing is introducing the use of "helper"
vCPUs that may jump from one host processor to another. Those will
be very happy to trigger a synchronize_rcu(), and the effect on
performance is quite the disaster"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (298 commits)
KVM: x86: Break CONFIG_KVM_X86's direct dependency on KVM_INTEL || KVM_AMD
KVM: x86: add back X86_LOCAL_APIC dependency
Revert "KVM: VMX: Move LOAD_IA32_PERF_GLOBAL_CTRL errata handling out of setup_vmcs_config()"
KVM: x86: switch hugepage recovery thread to vhost_task
KVM: x86: expose MSR_PLATFORM_INFO as a feature MSR
x86: KVM: Advertise CPUIDs for new instructions in Clearwater Forest
Documentation: KVM: fix malformed table
irqchip/loongson-eiointc: Add virt extension support
LoongArch: KVM: Add irqfd support
LoongArch: KVM: Add PCHPIC user mode read and write functions
LoongArch: KVM: Add PCHPIC read and write functions
LoongArch: KVM: Add PCHPIC device support
LoongArch: KVM: Add EIOINTC user mode read and write functions
LoongArch: KVM: Add EIOINTC read and write functions
LoongArch: KVM: Add EIOINTC device support
LoongArch: KVM: Add IPI user mode read and write function
LoongArch: KVM: Add IPI read and write function
LoongArch: KVM: Add IPI device support
LoongArch: KVM: Add iocsr and mmio bus simulation in kernel
KVM: arm64: Pass on SVE mapping failures
...
Pull MM updates from Andrew Morton:
- The series "zram: optimal post-processing target selection" from
Sergey Senozhatsky improves zram's post-processing selection
algorithm. This leads to improved memory savings.
- Wei Yang has gone to town on the mapletree code, contributing several
series which clean up the implementation:
- "refine mas_mab_cp()"
- "Reduce the space to be cleared for maple_big_node"
- "maple_tree: simplify mas_push_node()"
- "Following cleanup after introduce mas_wr_store_type()"
- "refine storing null"
- The series "selftests/mm: hugetlb_fault_after_madv improvements" from
David Hildenbrand fixes this selftest for s390.
- The series "introduce pte_offset_map_{ro|rw}_nolock()" from Qi Zheng
implements some rationaizations and cleanups in the page mapping
code.
- The series "mm: optimize shadow entries removal" from Shakeel Butt
optimizes the file truncation code by speeding up the handling of
shadow entries.
- The series "Remove PageKsm()" from Matthew Wilcox completes the
migration of this flag over to being a folio-based flag.
- The series "Unify hugetlb into arch_get_unmapped_area functions" from
Oscar Salvador implements a bunch of consolidations and cleanups in
the hugetlb code.
- The series "Do not shatter hugezeropage on wp-fault" from Dev Jain
takes away the wp-fault time practice of turning a huge zero page
into small pages. Instead we replace the whole thing with a THP. More
consistent cleaner and potentiall saves a large number of pagefaults.
- The series "percpu: Add a test case and fix for clang" from Andy
Shevchenko enhances and fixes the kernel's built in percpu test code.
- The series "mm/mremap: Remove extra vma tree walk" from Liam Howlett
optimizes mremap() by avoiding doing things which we didn't need to
do.
- The series "Improve the tmpfs large folio read performance" from
Baolin Wang teaches tmpfs to copy data into userspace at the folio
size rather than as individual pages. A 20% speedup was observed.
- The series "mm/damon/vaddr: Fix issue in
damon_va_evenly_split_region()" fro Zheng Yejian fixes DAMON
splitting.
- The series "memcg-v1: fully deprecate charge moving" from Shakeel
Butt removes the long-deprecated memcgv2 charge moving feature.
- The series "fix error handling in mmap_region() and refactor" from
Lorenzo Stoakes cleanup up some of the mmap() error handling and
addresses some potential performance issues.
- The series "x86/module: use large ROX pages for text allocations"
from Mike Rapoport teaches x86 to use large pages for
read-only-execute module text.
- The series "page allocation tag compression" from Suren Baghdasaryan
is followon maintenance work for the new page allocation profiling
feature.
- The series "page->index removals in mm" from Matthew Wilcox remove
most references to page->index in mm/. A slow march towards shrinking
struct page.
- The series "damon/{self,kunit}tests: minor fixups for DAMON debugfs
interface tests" from Andrew Paniakin performs maintenance work for
DAMON's self testing code.
- The series "mm: zswap swap-out of large folios" from Kanchana Sridhar
improves zswap's batching of compression and decompression. It is a
step along the way towards using Intel IAA hardware acceleration for
this zswap operation.
- The series "kasan: migrate the last module test to kunit" from
Sabyrzhan Tasbolatov completes the migration of the KASAN built-in
tests over to the KUnit framework.
- The series "implement lightweight guard pages" from Lorenzo Stoakes
permits userapace to place fault-generating guard pages within a
single VMA, rather than requiring that multiple VMAs be created for
this. Improved efficiencies for userspace memory allocators are
expected.
- The series "memcg: tracepoint for flushing stats" from JP Kobryn uses
tracepoints to provide increased visibility into memcg stats flushing
activity.
- The series "zram: IDLE flag handling fixes" from Sergey Senozhatsky
fixes a zram buglet which potentially affected performance.
- The series "mm: add more kernel parameters to control mTHP" from
Maíra Canal enhances our ability to control/configuremultisize THP
from the kernel boot command line.
- The series "kasan: few improvements on kunit tests" from Sabyrzhan
Tasbolatov has a couple of fixups for the KASAN KUnit tests.
- The series "mm/list_lru: Split list_lru lock into per-cgroup scope"
from Kairui Song optimizes list_lru memory utilization when lockdep
is enabled.
* tag 'mm-stable-2024-11-18-19-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (215 commits)
cma: enforce non-zero pageblock_order during cma_init_reserved_mem()
mm/kfence: add a new kunit test test_use_after_free_read_nofault()
zram: fix NULL pointer in comp_algorithm_show()
memcg/hugetlb: add hugeTLB counters to memcg
vmstat: call fold_vm_zone_numa_events() before show per zone NUMA event
mm: mmap_lock: check trace_mmap_lock_$type_enabled() instead of regcount
zram: ZRAM_DEF_COMP should depend on ZRAM
MAINTAINERS/MEMORY MANAGEMENT: add document files for mm
Docs/mm/damon: recommend academic papers to read and/or cite
mm: define general function pXd_init()
kmemleak: iommu/iova: fix transient kmemleak false positive
mm/list_lru: simplify the list_lru walk callback function
mm/list_lru: split the lock to per-cgroup scope
mm/list_lru: simplify reparenting and initial allocation
mm/list_lru: code clean up for reparenting
mm/list_lru: don't export list_lru_add
mm/list_lru: don't pass unnecessary key parameters
kasan: add kunit tests for kmalloc_track_caller, kmalloc_node_track_caller
kasan: change kasan_atomics kunit test as KUNIT_CASE_SLOW
kasan: use EXPORT_SYMBOL_IF_KUNIT to export symbols
...
Pull tdx updates from Dave Hansen:
"These essentially refine some interactions between TDX guests and
VMMs.
The first leverages a new TDX module feature to runtime disable the
ability for a VM to inject #VE exceptions. Before this feature, there
was only a static on/off switch and the guest had to panic if it was
configured in a bad state.
The second lets the guest opt in to be able to access the topology
CPUID leaves. Before this, accesses to those leaves would #VE.
For both of these, it would have been nicest to just change the
default behavior, but some pesky "other" OSes evidently need to retain
the legacy behavior.
Summary:
- Add new infrastructure for reading TDX metadata
- Use the newly-available metadata to:
- Disable potentially nasty #VE exceptions
- Get more complete CPU topology information from the VMM"
* tag 'x86_tdx_for_6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/tdx: Enable CPU topology enumeration
x86/tdx: Dynamically disable SEPT violations from causing #VEs
x86/tdx: Rename tdx_parse_tdinfo() to tdx_setup()
x86/tdx: Introduce wrappers to read and write TD metadata
Pull misc x86 updates from Dave Hansen:
"As usual for this branch, these are super random: a compile fix for
some newish LLVM checks and making sure a Kconfig text reference to
'RSB' matches the normal definition:
- Rework some CPU setup code to keep LLVM happy on 32-bit
- Correct RSB terminology in Kconfig text"
* tag 'x86_misc_for_6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/cpu: Make sure flag_is_changeable_p() is always being used
x86/bugs: Correct RSB terminology in Kconfig
Pull asm-generic updates from Arnd Bergmann:
"These are a number of unrelated cleanups, generally simplifying the
architecture specific header files:
- A series from Al Viro simplifies asm/vga.h, after it turns out that
most of it can be generalized.
- A series from Julian Vetter adds a common version of
memcpy_{to,from}io() and memset_io() and changes most architectures
to use that instead of their own implementation
- A series from Niklas Schnelle concludes his work to make PC style
inb()/outb() optional
- Nicolas Pitre contributes improvements for the generic do_div()
helper
- Christoph Hellwig adds a generic version of page_to_phys() and
phys_to_page(), replacing the slightly different architecture
specific definitions.
- Uwe Kleine-Koenig has a minor cleanup for ioctl definitions"
* tag 'asm-generic-3.13' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: (24 commits)
empty include/asm-generic/vga.h
sparc: get rid of asm/vga.h
asm/vga.h: don't bother with scr_mem{cpy,move}v() unless we need to
vt_buffer.h: get rid of dead code in default scr_...() instances
tty: serial: export serial_8250_warn_need_ioport
lib/iomem_copy: fix kerneldoc format style
hexagon: simplify asm/io.h for !HAS_IOPORT
loongarch: Use new fallback IO memcpy/memset
csky: Use new fallback IO memcpy/memset
arm64: Use new fallback IO memcpy/memset
New implementation for IO memcpy and IO memset
watchdog: Add HAS_IOPORT dependency for SBC8360 and SBC7240
__arch_xprod64(): make __always_inline when optimizing for performance
ARM: div64: improve __arch_xprod_64()
asm-generic/div64: optimize/simplify __div64_const32()
lib/math/test_div64: add some edge cases relevant to __div64_const32()
asm-generic: add an optional pfn_valid check to page_to_phys
asm-generic: provide generic page_to_phys and phys_to_page implementations
asm-generic/io.h: Remove I/O port accessors for HAS_IOPORT=n
tty: serial: handle HAS_IOPORT dependencies
...
Pull ftrace updates from Steven Rostedt:
- Restructure the function graph shadow stack to prepare it for use
with kretprobes
With the goal of merging the shadow stack logic of function graph and
kretprobes, some more restructuring of the function shadow stack is
required.
Move out function graph specific fields from the fgraph
infrastructure and store it on the new stack variables that can pass
data from the entry callback to the exit callback.
Hopefully, with this change, the merge of kretprobes to use fgraph
shadow stacks will be ready by the next merge window.
- Make shadow stack 4k instead of using PAGE_SIZE.
Some architectures have very large PAGE_SIZE values which make its
use for shadow stacks waste a lot of memory.
- Give shadow stacks its own kmem cache.
When function graph is started, every task on the system gets a
shadow stack. In the future, shadow stacks may not be 4K in size.
Have it have its own kmem cache so that whatever size it becomes will
still be efficient in allocations.
- Initialize profiler graph ops as it will be needed for new updates to
fgraph
- Convert to use guard(mutex) for several ftrace and fgraph functions
- Add more comments and documentation
- Show function return address in function graph tracer
Add an option to show the caller of a function at each entry of the
function graph tracer, similar to what the function tracer does.
- Abstract out ftrace_regs from being used directly like pt_regs
ftrace_regs was created to store a partial pt_regs. It holds only the
registers and stack information to get to the function arguments and
return values. On several archs, it is simply a wrapper around
pt_regs. But some users would access ftrace_regs directly to get the
pt_regs which will not work on all archs. Make ftrace_regs an
abstract structure that requires all access to its fields be through
accessor functions.
- Show how long it takes to do function code modifications
When code modification for function hooks happen, it always had the
time recorded in how long it took to do the conversion. But this
value was never exported. Recently the code was touched due to new
ROX modification handling that caused a large slow down in doing the
modifications and had a significant impact on boot times.
Expose the timings in the dyn_ftrace_total_info file. This file was
created a while ago to show information about memory usage and such
to implement dynamic function tracing. It's also an appropriate file
to store the timings of this modification as well. This will make it
easier to see the impact of changes to code modification on boot up
timings.
- Other clean ups and small fixes
* tag 'ftrace-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (22 commits)
ftrace: Show timings of how long nop patching took
ftrace: Use guard to take ftrace_lock in ftrace_graph_set_hash()
ftrace: Use guard to take the ftrace_lock in release_probe()
ftrace: Use guard to lock ftrace_lock in cache_mod()
ftrace: Use guard for match_records()
fgraph: Use guard(mutex)(&ftrace_lock) for unregister_ftrace_graph()
fgraph: Give ret_stack its own kmem cache
fgraph: Separate size of ret_stack from PAGE_SIZE
ftrace: Rename ftrace_regs_return_value to ftrace_regs_get_return_value
selftests/ftrace: Fix check of return value in fgraph-retval.tc test
ftrace: Use arch_ftrace_regs() for ftrace_regs_*() macros
ftrace: Consolidate ftrace_regs accessor functions for archs using pt_regs
ftrace: Make ftrace_regs abstract from direct use
fgragh: No need to invoke the function call_filter_check_discard()
fgraph: Simplify return address printing in function graph tracer
function_graph: Remove unnecessary initialization in ftrace_graph_ret_addr()
function_graph: Support recording and printing the function return address
ftrace: Have calltime be saved in the fgraph storage
ftrace: Use a running sleeptime instead of saving on shadow stack
fgraph: Use fgraph data to store subtime for profiler
...
Pull timer updates from Thomas Gleixner:
"A rather large update for timekeeping and timers:
- The final step to get rid of auto-rearming posix-timers
posix-timers are currently auto-rearmed by the kernel when the
signal of the timer is ignored so that the timer signal can be
delivered once the corresponding signal is unignored.
This requires to throttle the timer to prevent a DoS by small
intervals and keeps the system pointlessly out of low power states
for no value. This is a long standing non-trivial problem due to
the lock order of posix-timer lock and the sighand lock along with
life time issues as the timer and the sigqueue have different life
time rules.
Cure this by:
- Embedding the sigqueue into the timer struct to have the same
life time rules. Aside of that this also avoids the lookup of
the timer in the signal delivery and rearm path as it's just a
always valid container_of() now.
- Queuing ignored timer signals onto a seperate ignored list.
- Moving queued timer signals onto the ignored list when the
signal is switched to SIG_IGN before it could be delivered.
- Walking the ignored list when SIG_IGN is lifted and requeue the
signals to the actual signal lists. This allows the signal
delivery code to rearm the timer.
This also required to consolidate the signal delivery rules so they
are consistent across all situations. With that all self test
scenarios finally succeed.
- Core infrastructure for VFS multigrain timestamping
This is required to allow the kernel to use coarse grained time
stamps by default and switch to fine grained time stamps when inode
attributes are actively observed via getattr().
These changes have been provided to the VFS tree as well, so that
the VFS specific infrastructure could be built on top.
- Cleanup and consolidation of the sleep() infrastructure
- Move all sleep and timeout functions into one file
- Rework udelay() and ndelay() into proper documented inline
functions and replace the hardcoded magic numbers by proper
defines.
- Rework the fsleep() implementation to take the reality of the
timer wheel granularity on different HZ values into account.
Right now the boundaries are hard coded time ranges which fail
to provide the requested accuracy on different HZ settings.
- Update documentation for all sleep/timeout related functions
and fix up stale documentation links all over the place
- Fixup a few usage sites
- Rework of timekeeping and adjtimex(2) to prepare for multiple PTP
clocks
A system can have multiple PTP clocks which are participating in
seperate and independent PTP clock domains. So far the kernel only
considers the PTP clock which is based on CLOCK TAI relevant as
that's the clock which drives the timekeeping adjustments via the
various user space daemons through adjtimex(2).
The non TAI based clock domains are accessible via the file
descriptor based posix clocks, but their usability is very limited.
They can't be accessed fast as they always go all the way out to
the hardware and they cannot be utilized in the kernel itself.
As Time Sensitive Networking (TSN) gains traction it is required to
provide fast user and kernel space access to these clocks.
The approach taken is to utilize the timekeeping and adjtimex(2)
infrastructure to provide this access in a similar way how the
kernel provides access to clock MONOTONIC, REALTIME etc.
Instead of creating a duplicated infrastructure this rework
converts timekeeping and adjtimex(2) into generic functionality
which operates on pointers to data structures instead of using
static variables.
This allows to provide time accessors and adjtimex(2) functionality
for the independent PTP clocks in a subsequent step.
- Consolidate hrtimer initialization
hrtimers are set up by initializing the data structure and then
seperately setting the callback function for historical reasons.
That's an extra unnecessary step and makes Rust support less
straight forward than it should be.
Provide a new set of hrtimer_setup*() functions and convert the
core code and a few usage sites of the less frequently used
interfaces over.
The bulk of the htimer_init() to hrtimer_setup() conversion is
already prepared and scheduled for the next merge window.
- Drivers:
- Ensure that the global timekeeping clocksource is utilizing the
cluster 0 timer on MIPS multi-cluster systems.
Otherwise CPUs on different clusters use their cluster specific
clocksource which is not guaranteed to be synchronized with
other clusters.
- Mostly boring cleanups, fixes, improvements and code movement"
* tag 'timers-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (140 commits)
posix-timers: Fix spurious warning on double enqueue versus do_exit()
clocksource/drivers/arm_arch_timer: Use of_property_present() for non-boolean properties
clocksource/drivers/gpx: Remove redundant casts
clocksource/drivers/timer-ti-dm: Fix child node refcount handling
dt-bindings: timer: actions,owl-timer: convert to YAML
clocksource/drivers/ralink: Add Ralink System Tick Counter driver
clocksource/drivers/mips-gic-timer: Always use cluster 0 counter as clocksource
clocksource/drivers/timer-ti-dm: Don't fail probe if int not found
clocksource/drivers:sp804: Make user selectable
clocksource/drivers/dw_apb: Remove unused dw_apb_clockevent functions
hrtimers: Delete hrtimer_init_on_stack()
alarmtimer: Switch to use hrtimer_setup() and hrtimer_setup_on_stack()
io_uring: Switch to use hrtimer_setup_on_stack()
sched/idle: Switch to use hrtimer_setup_on_stack()
hrtimers: Delete hrtimer_init_sleeper_on_stack()
wait: Switch to use hrtimer_setup_sleeper_on_stack()
timers: Switch to use hrtimer_setup_sleeper_on_stack()
net: pktgen: Switch to use hrtimer_setup_sleeper_on_stack()
futex: Switch to use hrtimer_setup_sleeper_on_stack()
fs/aio: Switch to use hrtimer_setup_sleeper_on_stack()
...
Pull vdso data page handling updates from Thomas Gleixner:
"First steps of consolidating the VDSO data page handling.
The VDSO data page handling is architecture specific for historical
reasons, but there is no real technical reason to do so.
Aside of that VDSO data has become a dump ground for various
mechanisms and fail to provide a clear separation of the
functionalities.
Clean this up by:
- consolidating the VDSO page data by getting rid of architecture
specific warts especially in x86 and PowerPC.
- removing the last includes of header files which are pulling in
other headers outside of the VDSO namespace.
- seperating timekeeping and other VDSO data accordingly.
Further consolidation of the VDSO page handling is done in subsequent
changes scheduled for the next merge window.
This also lays the ground for expanding the VDSO time getters for
independent PTP clocks in a generic way without making every
architecture add support seperately"
* tag 'timers-vdso-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (42 commits)
x86/vdso: Add missing brackets in switch case
vdso: Rename struct arch_vdso_data to arch_vdso_time_data
powerpc: Split systemcfg struct definitions out from vdso
powerpc: Split systemcfg data out of vdso data page
powerpc: Add kconfig option for the systemcfg page
powerpc/pseries/lparcfg: Use num_possible_cpus() for potential processors
powerpc/pseries/lparcfg: Fix printing of system_active_processors
powerpc/procfs: Propagate error of remap_pfn_range()
powerpc/vdso: Remove offset comment from 32bit vdso_arch_data
x86/vdso: Split virtual clock pages into dedicated mapping
x86/vdso: Delete vvar.h
x86/vdso: Access vdso data without vvar.h
x86/vdso: Move the rng offset to vsyscall.h
x86/vdso: Access rng vdso data without vvar.h
x86/vdso: Access timens vdso data without vvar.h
x86/vdso: Allocate vvar page from C code
x86/vdso: Access rng data from kernel without vvar
x86/vdso: Place vdso_data at beginning of vvar page
x86/vdso: Use __arch_get_vdso_data() to access vdso data
x86/mm/mmap: Remove arch_vma_name()
...
Pull x86 splitlock updates from Ingo Molnar:
- Move Split and Bus lock code to a dedicated file (Ravi Bangoria)
- Add split/bus lock support for AMD (Ravi Bangoria)
* tag 'x86-splitlock-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/bus_lock: Add support for AMD
x86/split_lock: Move Split and Bus lock code to a dedicated file
Pull performance events updates from Ingo Molnar:
"Uprobes:
- Add BPF session support (Jiri Olsa)
- Switch to RCU Tasks Trace flavor for better performance (Andrii
Nakryiko)
- Massively increase uretprobe SMP scalability by SRCU-protecting
the uretprobe lifetime (Andrii Nakryiko)
- Kill xol_area->slot_count (Oleg Nesterov)
Core facilities:
- Implement targeted high-frequency profiling by adding the ability
for an event to "pause" or "resume" AUX area tracing (Adrian
Hunter)
VM profiling/sampling:
- Correct perf sampling with guest VMs (Colton Lewis)
New hardware support:
- x86/intel: Add PMU support for Intel ArrowLake-H CPUs (Dapeng Mi)
Misc fixes and enhancements:
- x86/intel/pt: Fix buffer full but size is 0 case (Adrian Hunter)
- x86/amd: Warn only on new bits set (Breno Leitao)
- x86/amd/uncore: Avoid a false positive warning about snprintf
truncation in amd_uncore_umc_ctx_init (Jean Delvare)
- uprobes: Re-order struct uprobe_task to save some space
(Christophe JAILLET)
- x86/rapl: Move the pmu allocation out of CPU hotplug (Kan Liang)
- x86/rapl: Clean up cpumask and hotplug (Kan Liang)
- uprobes: Deuglify xol_get_insn_slot/xol_free_insn_slot paths (Oleg
Nesterov)"
* tag 'perf-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (32 commits)
perf/core: Correct perf sampling with guest VMs
perf/x86: Refactor misc flag assignments
perf/powerpc: Use perf_arch_instruction_pointer()
perf/core: Hoist perf_instruction_pointer() and perf_misc_flags()
perf/arm: Drop unused functions
uprobes: Re-order struct uprobe_task to save some space
perf/x86/amd/uncore: Avoid a false positive warning about snprintf truncation in amd_uncore_umc_ctx_init
perf/x86/intel: Do not enable large PEBS for events with aux actions or aux sampling
perf/x86/intel/pt: Add support for pause / resume
perf/core: Add aux_pause, aux_resume, aux_start_paused
perf/x86/intel/pt: Fix buffer full but size is 0 case
uprobes: SRCU-protect uretprobe lifetime (with timeout)
uprobes: allow put_uprobe() from non-sleepable softirq context
perf/x86/rapl: Clean up cpumask and hotplug
perf/x86/rapl: Move the pmu allocation out of CPU hotplug
uprobe: Add support for session consumer
uprobe: Add data pointer to consumer handlers
perf/x86/amd: Warn only on new bits set
uprobes: fold xol_take_insn_slot() into xol_get_insn_slot()
uprobes: kill xol_area->slot_count
...
Pull x86 cpuid updates from Borislav Petkov:
- Add a feature flag which denotes AMD CPUs supporting workload
classification with the purpose of using such hints when making
scheduling decisions
- Determine the boost enumerator for each AMD core based on its type:
efficiency or performance, in the cppc driver
- Add the type of a CPU to the topology CPU descriptor with the goal of
supporting and making decisions based on the type of the respective
core
- Add a feature flag to denote AMD cores which have heterogeneous
topology and enable SD_ASYM_PACKING for those
- Check microcode revisions before disabling PCID on Intel
- Cleanups and fixlets
* tag 'x86_cpu_for_v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/cpu: Remove redundant CONFIG_NUMA guard around numa_add_cpu()
x86/cpu: Fix FAM5_QUARK_X1000 to use X86_MATCH_VFM()
x86/cpu: Fix formatting of cpuid_bits[] in scattered.c
x86/cpufeatures: Add X86_FEATURE_AMD_WORKLOAD_CLASS feature bit
x86/amd: Use heterogeneous core topology for identifying boost numerator
x86/cpu: Add CPU type to struct cpuinfo_topology
x86/cpu: Enable SD_ASYM_PACKING for PKG domain on AMD
x86/cpufeatures: Add X86_FEATURE_AMD_HETEROGENEOUS_CORES
x86/cpufeatures: Rename X86_FEATURE_FAST_CPPC to have AMD prefix
x86/mm: Don't disable PCID when INVLPG has been fixed by microcode
Pull x86 SEV updates from Borislav Petkov:
- Do the proper memory conversion of guest memory in order to be able
to kexec kernels in SNP guests along with other adjustments and
cleanups to that effect
- Start converting and moving functionality from the sev-guest driver
into core code with the purpose of supporting the secure TSC SNP
feature where the hypervisor cannot influence the TSC exposed to the
guest anymore
- Add a "nosnp" cmdline option in order to be able to disable SNP
support in the hypervisor and thus free-up resources which are not
going to be used
- Cleanups
[ Reminding myself about the endless TLA's again: SEV is the AMD Secure
Encrypted Virtualization - Linus ]
* tag 'x86_sev_for_v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/sev: Cleanup vc_handle_msr()
x86/sev: Convert shared memory back to private on kexec
x86/mm: Refactor __set_clr_pte_enc()
x86/boot: Skip video memory access in the decompressor for SEV-ES/SNP
virt: sev-guest: Carve out SNP message context structure
virt: sev-guest: Reduce the scope of SNP command mutex
virt: sev-guest: Consolidate SNP guest messaging parameters to a struct
x86/sev: Cache the secrets page address
x86/sev: Handle failures from snp_init()
virt: sev-guest: Use AES GCM crypto library
x86/virt: Provide "nosnp" boot option for sev kernel command line
x86/virt: Move SEV-specific parsing into arch/x86/virt/svm
Pull RAS updates from Borislav Petkov:
- Log and handle twp new AMD-specific MCA registers: SYND1 and SYND2
and report the Field Replaceable Unit text info reported through them
- Add support for handling variable-sized SMCA BERT records
- Add the capability for reporting vendor-specific RAS error info
without adding vendor-specific fields to struct mce
- Cleanups
* tag 'ras_core_for_v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
EDAC/mce_amd: Add support for FRU text in MCA
x86/mce/apei: Handle variable SMCA BERT record size
x86/MCE/AMD: Add support for new MCA_SYND{1,2} registers
tracing: Add __print_dynamic_array() helper
x86/mce: Add wrapper for struct mce to export vendor specific info
x86/mce/intel: Use MCG_BANKCNT_MASK instead of 0xff
x86/mce/mcelog: Use xchg() to get and clear the flags
Pull x86 fixes from Borislav Petkov:
- Make sure a kdump kernel with CONFIG_IMA_KEXEC enabled and booted on
an AMD SME enabled hardware properly decrypts the ima_kexec buffer
information passed to it from the previous kernel
- Fix building the kernel with Clang where a non-TLS definition of the
stack protector guard cookie leads to bogus code generation
- Clear a wrongly advertised virtualized VMLOAD/VMSAVE feature flag on
some Zen4 client systems as those insns are not supported on client
* tag 'x86_urgent_for_v6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm: Fix a kdump kernel failure on SME system when CONFIG_IMA_KEXEC=y
x86/stackprotector: Work around strict Clang TLS symbol requirements
x86/CPU/AMD: Clear virtualized VMLOAD/VMSAVE on Zen4 client
kvm_vm_create_worker_thread() is meant to be used for kthreads that
can consume significant amounts of CPU time on behalf of a VM or in
response to how the VM behaves (for example how it accesses its memory).
Therefore it wants to charge the CPU time consumed by that work to
the VM's container.
However, because of these threads, cgroups which have kvm instances
inside never complete freezing. This can be trivially reproduced:
root@test ~# mkdir /sys/fs/cgroup/test
root@test ~# echo $$ > /sys/fs/cgroup/test/cgroup.procs
root@test ~# qemu-system-x86_64 -nographic -enable-kvm
and in another terminal:
root@test ~# echo 1 > /sys/fs/cgroup/test/cgroup.freeze
root@test ~# cat /sys/fs/cgroup/test/cgroup.events
populated 1
frozen 0
The cgroup freezing happens in the signal delivery path but
kvm_nx_huge_page_recovery_worker, while joining non-root cgroups, never
calls into the signal delivery path and thus never gets frozen. Because
the cgroup freezer determines whether a given cgroup is frozen by
comparing the number of frozen threads to the total number of threads
in the cgroup, the cgroup never becomes frozen and users waiting for
the state transition may hang indefinitely.
Since the worker kthread is tied to a user process, it's better if
it behaves similarly to user tasks as much as possible, including
being able to send SIGSTOP and SIGCONT. In fact, vhost_task is all
that kvm_vm_create_worker_thread() wanted to be and more: not only it
inherits the userspace process's cgroups, it has other niceties like
being parented properly in the process tree. Use it instead of the
homegrown alternative.
Incidentally, the new code is also better behaved when you flip recovery
back and forth to disabled and back to enabled. If your recovery period
is 1 minute, it will run the next recovery after 1 minute independent
of how many times you flipped the parameter.
(Commit message based on emails from Tejun).
Reported-by: Tejun Heo <tj@kernel.org>
Reported-by: Luca Boccassi <bluca@debian.org>
Acked-by: Tejun Heo <tj@kernel.org>
Tested-by: Luca Boccassi <bluca@debian.org>
Cc: stable@vger.kernel.org
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
LoongArch KVM changes for v6.13
1. Add iocsr and mmio bus simulation in kernel.
2. Add in-kernel interrupt controller emulation.
3. Add virt extension support for eiointc irqchip.
Latest Intel platform Clearwater Forest has introduced new instructions
enumerated by CPUIDs of SHA512, SM3, SM4 and AVX-VNNI-INT16. Advertise
these CPUIDs to userspace so that guests can query them directly.
SHA512, SM3 and SM4 are on an expected-dense CPUID leaf and some other
bits on this leaf have kernel usages. Considering they have not truly
kernel usages, hide them in /proc/cpuinfo.
These new instructions only operate in xmm, ymm registers and have no new
VMX controls, so there is no additional host enabling required for guests
to use these instructions, i.e. advertising these CPUIDs to userspace is
safe.
Tested-by: Jiaan Lu <jiaan.lu@intel.com>
Tested-by: Xuelian Guo <xuelian.guo@intel.com>
Signed-off-by: Tao Su <tao1.su@linux.intel.com>
Message-ID: <20241105054825.870939-1-tao1.su@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
- Drop obsolete references to PPC970 KVM, which was removed 10 years ago.
- Fix incorrect references to non-existing ioctls
- List registers supported by KVM_GET/SET_ONE_REG on s390
- Use rST internal links
- Reorganize the introduction to the API document
KVM x86 misc changes for 6.13
- Clean up and optimize KVM's handling of writes to MSR_IA32_APICBASE.
- Quirk KVM's misguided behavior of initialized certain feature MSRs to
their maximum supported feature set, which can result in KVM creating
invalid vCPU state. E.g. initializing PERF_CAPABILITIES to a non-zero
value results in the vCPU having invalid state if userspace hides PDCM
from the guest, which can lead to save/restore failures.
- Fix KVM's handling of non-canonical checks for vCPUs that support LA57
to better follow the "architecture", in quotes because the actual
behavior is poorly documented. E.g. most MSR writes and descriptor
table loads ignore CR4.LA57 and operate purely on whether the CPU
supports LA57.
- Bypass the register cache when querying CPL from kvm_sched_out(), as
filling the cache from IRQ context is generally unsafe, and harden the
cache accessors to try to prevent similar issues from occuring in the
future.
- Advertise AMD_IBPB_RET to userspace, and fix a related bug where KVM
over-advertises SPEC_CTRL when trying to support cross-vendor VMs.
- Minor cleanups
KVM x86 MMU changes for 6.13
- Cleanup KVM's handling of Accessed and Dirty bits to dedup code, improve
documentation, harden against unexpected changes, and to simplify
A/D-disabled MMUs by using the hardware-defined A/D bits to track if a
PFN is Accessed and/or Dirty.
- Elide TLB flushes when aging SPTEs, as has been done in x86's primary
MMU for over 10 years.
- Batch TLB flushes when zapping collapsible TDP MMU SPTEs, i.e. when
dirty logging is toggled off, which reduces the time it takes to disable
dirty logging by ~3x.
- Recover huge pages in-place in the TDP MMU instead of zapping the SP
and waiting until the page is re-accessed to create a huge mapping.
Proactively installing huge pages can reduce vCPU jitter in extreme
scenarios.
- Remove support for (poorly) reclaiming page tables in shadow MMUs via
the primary MMU's shrinker interface.
When flag_is_changeable_p() is unused, it prevents kernel builds
with clang, `make W=1` and CONFIG_WERROR=y:
arch/x86/kernel/cpu/common.c:351:19: error: unused function 'flag_is_changeable_p' [-Werror,-Wunused-function]
351 | static inline int flag_is_changeable_p(u32 flag)
| ^~~~~~~~~~~~~~~~~~~~
Fix this by moving core around to make sure flag_is_changeable_p() is
always being used.
See also commit 6863f5643d ("kbuild: allow Clang to find unused static
inline functions for W=1 build").
While at it, fix the argument type to be unsigned long along with
the local variables, although it currently only runs in 32-bit cases.
Besides that, makes it return boolean instead of int. This induces
the change of the returning type of have_cpuid_p() to be boolean
as well.
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Link: https://lore.kernel.org/all/20241108153105.1578186-1-andriy.shevchenko%40linux.intel.com
GCC and Clang both implement stack protector support based on Thread Local
Storage (TLS) variables, and this is used in the kernel to implement per-task
stack cookies, by copying a task's stack cookie into a per-CPU variable every
time it is scheduled in.
Both now also implement -mstack-protector-guard-symbol=, which permits the TLS
variable to be specified directly. This is useful because it will allow to
move away from using a fixed offset of 40 bytes into the per-CPU area on
x86_64, which requires a lot of special handling in the per-CPU code and the
runtime relocation code.
However, while GCC is rather lax in its implementation of this command line
option, Clang actually requires that the provided symbol name refers to a TLS
variable (i.e., one declared with __thread), although it also permits the
variable to be undeclared entirely, in which case it will use an implicit
declaration of the right type.
The upshot of this is that Clang will emit the correct references to the stack
cookie variable in most cases, e.g.,
10d: 64 a1 00 00 00 00 mov %fs:0x0,%eax
10f: R_386_32 __stack_chk_guard
However, if a non-TLS definition of the symbol in question is visible in the
same compilation unit (which amounts to the whole of vmlinux if LTO is
enabled), it will drop the per-CPU prefix and emit a load from a bogus
address.
Work around this by using a symbol name that never occurs in C code, and emit
it as an alias in the linker script.
Fixes: 3fb0fdb3bb ("x86/stackprotector/32: Make the canary into a regular percpu variable")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Cc: stable@vger.kernel.org
Link: https://github.com/ClangBuiltLinux/linux/issues/1854
Link: https://lore.kernel.org/r/20241105155801.1779119-2-brgerst@gmail.com
TDX 1.0 defines baseline behaviour of TDX guest platform. TDX 1.0
generates a #VE when accessing topology-related CPUID leafs (0xB and
0x1F) and the X2APIC_APICID MSR. The kernel returns all zeros on CPUID
topology. In practice, this means that the kernel can only boot with a
plain topology. Any complications will cause problems.
The ENUM_TOPOLOGY feature allows the VMM to provide topology
information to the guest. Enabling the feature eliminates
topology-related #VEs: the TDX module virtualizes accesses to
the CPUID leafs and the MSR.
Enable ENUM_TOPOLOGY if it is available.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/all/20241104103803.195705-5-kirill.shutemov%40linux.intel.com
Memory access #VEs are hard for Linux to handle in contexts like the
entry code or NMIs. But other OSes need them for functionality.
There's a static (pre-guest-boot) way for a VMM to choose one or the
other. But VMMs don't always know which OS they are booting, so they
choose to deliver those #VEs so the "other" OSes will work. That,
unfortunately has left us in the lurch and exposed to these
hard-to-handle #VEs.
The TDX module has introduced a new feature. Even if the static
configuration is set to "send nasty #VEs", the kernel can dynamically
request that they be disabled. Once they are disabled, access to private
memory that is not in the Mapped state in the Secure-EPT (SEPT) will
result in an exit to the VMM rather than injecting a #VE.
Check if the feature is available and disable SEPT #VE if possible.
If the TD is allowed to disable/enable SEPT #VEs, the ATTR_SEPT_VE_DISABLE
attribute is no longer reliable. It reflects the initial state of the
control for the TD, but it will not be updated if someone (e.g. bootloader)
changes it before the kernel starts. Kernel must check TDCS_TD_CTLS bit to
determine if SEPT #VEs are enabled or disabled.
[ dhansen: remove 'return' at end of function ]
Fixes: 373e715e31 ("x86/tdx: Panic on bad configs that #VE on "private" memory access")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/all/20241104103803.195705-4-kirill.shutemov%40linux.intel.com
The TDG_VM_WR TDCALL is used to ask the TDX module to change some
TD-specific VM configuration. There is currently only one user in the
kernel of this TDCALL leaf. More will be added shortly.
Refactor to make way for more users of TDG_VM_WR who will need to modify
other TD configuration values.
Add a wrapper for the TDG_VM_RD TDCALL that requests TD-specific
metadata from the TDX module. There are currently no users for
TDG_VM_RD. Mark it as __maybe_unused until the first user appears.
This is preparation for enumeration and enabling optional TD features.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Link: https://lore.kernel.org/all/20241104103803.195705-2-kirill.shutemov%40linux.intel.com
Patch series "percpu: Add a test case and fix for clang", v2.
Add a test case to percpu to check a corner case with the specific 64-bit
unsigned value. This test case shows why the first patch is done in the
way it's done.
The before and after has been tested with binary comparison of the
percpu_test module and runnig it on the real Intel system.
This patch (of 2):
When percpu_add_op() is used with an unsigned argument, it prevents kernel
builds with clang, `make W=1` and CONFIG_WERROR=y:
net/ipv4/tcp_output.c:187:3: error: result of comparison of constant -1 with expression of type 'u8' (aka 'unsigned char') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
187 | NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPACKCOMPRESSED,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
188 | tp->compressed_ack);
| ~~~~~~~~~~~~~~~~~~~
...
arch/x86/include/asm/percpu.h:238:31: note: expanded from macro 'percpu_add_op'
238 | ((val) == 1 || (val) == -1)) ? \
| ~~~~~ ^ ~~
Fix this by casting -1 to the type of the parameter and then compare.
Link: https://lkml.kernel.org/r/20241016182635.1156168-1-andriy.shevchenko@linux.intel.com
Link: https://lkml.kernel.org/r/20241016182635.1156168-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
For clarity. It's increasingly hard to reason about the code, when KASLR
is moving around the boundaries. In this case where KASLR is randomizing
the location of the kernel image within physical memory, the maximum
number of address bits for physical memory has not changed.
What has changed is the ending address of memory that is allowed to be
directly mapped by the kernel.
Let's name the variable, and the associated macro accordingly.
Also, enhance the comment above the direct_map_physmem_end definition,
to further clarify how this all works.
Link: https://lkml.kernel.org/r/20241009025024.89813-1-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Jordan Niethe <jniethe@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
arch_init_invariance_cppc() is called at the end of
acpi_cppc_processor_probe() in order to configure frequency invariance
based upon the values from _CPC.
This however doesn't work on AMD CPPC shared memory designs that have
AMD preferred cores enabled because _CPC needs to be analyzed from all
cores to judge if preferred cores are enabled.
This issue manifests to users as a warning since commit 21fb59ab4b
("ACPI: CPPC: Adjust debug messages in amd_set_max_freq_ratio() to warn"):
```
Could not retrieve highest performance (-19)
```
However the warning isn't the cause of this, it was actually
commit 279f838a61 ("x86/amd: Detect preferred cores in
amd_get_boost_ratio_numerator()") which exposed the issue.
To fix this problem, change arch_init_invariance_cppc() into a new weak
symbol that is called at the end of acpi_processor_driver_init().
Each architecture that supports it can declare the symbol to override
the weak one.
Define it for x86, in arch/x86/kernel/acpi/cppc.c, and for all of the
architectures using the generic arch_topology.c code.
Fixes: 279f838a61 ("x86/amd: Detect preferred cores in amd_get_boost_ratio_numerator()")
Reported-by: Ivan Shapovalov <intelfx@intelfx.name>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219431
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://patch.msgid.link/20241104222855.3959267-1-superm1@kernel.org
[ rjw: Changelog edit ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Drop the per-VM zapped_obsolete_pages list now that the usage from the
defunct mmu_shrinker is gone, and instead use a local list to track pages
in kvm_zap_obsolete_pages(), the sole remaining user of
zapped_obsolete_pages.
Opportunistically add an assertion to verify and document that slots_lock
must be held, i.e. that there can only be one active instance of
kvm_zap_obsolete_pages() at any given time, and by doing so also prove
that using a local list instead of a per-VM list doesn't change any
functionality (beyond trivialities like list initialization).
Signed-off-by: Vipin Sharma <vipinsh@google.com>
Link: https://lore.kernel.org/r/20241101201437.1604321-2-vipinsh@google.com
[sean: split to separate patch, write changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Recover TDP MMU huge page mappings in-place instead of zapping them when
dirty logging is disabled, and rename functions that recover huge page
mappings when dirty logging is disabled to move away from the "zap
collapsible spte" terminology.
Before KVM flushes TLBs, guest accesses may be translated through either
the (stale) small SPTE or the (new) huge SPTE. This is already possible
when KVM is doing eager page splitting (where TLB flushes are also
batched), and when vCPUs are faulting in huge mappings (where TLBs are
flushed after the new huge SPTE is installed).
Recovering huge pages reduces the number of page faults when dirty
logging is disabled:
$ perf stat -e kvm:kvm_page_fault -- ./dirty_log_perf_test -s anonymous_hugetlb_2mb -v 64 -e -b 4g
Before: 393,599 kvm:kvm_page_fault
After: 262,575 kvm:kvm_page_fault
vCPU throughput and the latency of disabling dirty-logging are about
equal compared to zapping, but avoiding faults can be beneficial to
remove vCPU jitter in extreme scenarios.
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20240823235648.3236880-5-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
