Currently, when a nested MMU is repurposed for some other MMU context,
KVM unmaps everything during vcpu_load() while holding the MMU lock for
write. This is quite a performance bottleneck for large nested VMs, as
all vCPU scheduling will spin until the unmap completes.
Start punting the MMU cleanup to a vCPU request, where it is then
possible to periodically release the MMU lock and CPU in the presence of
contention.
Ensure that no vCPU winds up using a stale MMU by tracking the pending
unmap on the S2 MMU itself and requesting an unmap on every vCPU that
finds it.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241007233028.2236133-4-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>
Right now the nested code allows unmap operations on a shadow stage-2 to
block unconditionally. This is wrong in a couple places, such as a
non-blocking MMU notifier or on the back of a sched_in() notifier as
part of shadow MMU recycling.
Carry through whether or not blocking is allowed to
kvm_pgtable_stage2_unmap(). This 'fixes' an issue where stage-2 MMU
reclaim would precipitate a stack overflow from a pile of kvm_sched_in()
callbacks, all trying to recycle a stage-2 MMU.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241007233028.2236133-3-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>
If a vCPU is scheduling out and not in WFI emulation, it is highly
likely it will get scheduled again soon and reuse the MMU it had before.
Dropping the MMU at vcpu_put() can have some unfortunate consequences,
as the MMU could get reclaimed and used in a different context, forcing
another 'cold start' on an otherwise active MMU.
Avoid that altogether by keeping a reference on the MMU if the vCPU is
scheduling out, ensuring that another vCPU cannot reclaim it while the
current vCPU is away. Since there are more MMUs than vCPUs, this does
not affect the guarantee that an unused MMU is available at any time.
Furthermore, this makes the vcpu->arch.hw_mmu ~stable in preemptible
code, at least for where it matters in the stage-2 abort path. Yes, the
MMU can change across WFI emulation, but there isn't even a use case
where this would matter.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241007233028.2236133-2-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>
this pull request are:
"Align kvrealloc() with krealloc()" from Danilo Krummrich. Adds
consistency to the APIs and behaviour of these two core allocation
functions. This also simplifies/enables Rustification.
"Some cleanups for shmem" from Baolin Wang. No functional changes - mode
code reuse, better function naming, logic simplifications.
"mm: some small page fault cleanups" from Josef Bacik. No functional
changes - code cleanups only.
"Various memory tiering fixes" from Zi Yan. A small fix and a little
cleanup.
"mm/swap: remove boilerplate" from Yu Zhao. Code cleanups and
simplifications and .text shrinkage.
"Kernel stack usage histogram" from Pasha Tatashin and Shakeel Butt. This
is a feature, it adds new feilds to /proc/vmstat such as
$ grep kstack /proc/vmstat
kstack_1k 3
kstack_2k 188
kstack_4k 11391
kstack_8k 243
kstack_16k 0
which tells us that 11391 processes used 4k of stack while none at all
used 16k. Useful for some system tuning things, but partivularly useful
for "the dynamic kernel stack project".
"kmemleak: support for percpu memory leak detect" from Pavel Tikhomirov.
Teaches kmemleak to detect leaksage of percpu memory.
"mm: memcg: page counters optimizations" from Roman Gushchin. "3
independent small optimizations of page counters".
"mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from David
Hildenbrand. Improves PTE/PMD splitlock detection, makes powerpc/8xx work
correctly by design rather than by accident.
"mm: remove arch_make_page_accessible()" from David Hildenbrand. Some
folio conversions which make arch_make_page_accessible() unneeded.
"mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David Finkel.
Cleans up and fixes our handling of the resetting of the cgroup/process
peak-memory-use detector.
"Make core VMA operations internal and testable" from Lorenzo Stoakes.
Rationalizaion and encapsulation of the VMA manipulation APIs. With a
view to better enable testing of the VMA functions, even from a
userspace-only harness.
"mm: zswap: fixes for global shrinker" from Takero Funaki. Fix issues in
the zswap global shrinker, resulting in improved performance.
"mm: print the promo watermark in zoneinfo" from Kaiyang Zhao. Fill in
some missing info in /proc/zoneinfo.
"mm: replace follow_page() by folio_walk" from David Hildenbrand. Code
cleanups and rationalizations (conversion to folio_walk()) resulting in
the removal of follow_page().
"improving dynamic zswap shrinker protection scheme" from Nhat Pham. Some
tuning to improve zswap's dynamic shrinker. Significant reductions in
swapin and improvements in performance are shown.
"mm: Fix several issues with unaccepted memory" from Kirill Shutemov.
Improvements to the new unaccepted memory feature,
"mm/mprotect: Fix dax puds" from Peter Xu. Implements mprotect on DAX
PUDs. This was missing, although nobody seems to have notied yet.
"Introduce a store type enum for the Maple tree" from Sidhartha Kumar.
Cleanups and modest performance improvements for the maple tree library
code.
"memcg: further decouple v1 code from v2" from Shakeel Butt. Move more
cgroup v1 remnants away from the v2 memcg code.
"memcg: initiate deprecation of v1 features" from Shakeel Butt. Adds
various warnings telling users that memcg v1 features are deprecated.
"mm: swap: mTHP swap allocator base on swap cluster order" from Chris Li.
Greatly improves the success rate of the mTHP swap allocation.
"mm: introduce numa_memblks" from Mike Rapoport. Moves various disparate
per-arch implementations of numa_memblk code into generic code.
"mm: batch free swaps for zap_pte_range()" from Barry Song. Greatly
improves the performance of munmap() of swap-filled ptes.
"support large folio swap-out and swap-in for shmem" from Baolin Wang.
With this series we no longer split shmem large folios into simgle-page
folios when swapping out shmem.
"mm/hugetlb: alloc/free gigantic folios" from Yu Zhao. Nice performance
improvements and code reductions for gigantic folios.
"support shmem mTHP collapse" from Baolin Wang. Adds support for
khugepaged's collapsing of shmem mTHP folios.
"mm: Optimize mseal checks" from Pedro Falcato. Fixes an mprotect()
performance regression due to the addition of mseal().
"Increase the number of bits available in page_type" from Matthew Wilcox.
Increases the number of bits available in page_type!
"Simplify the page flags a little" from Matthew Wilcox. Many legacy page
flags are now folio flags, so the page-based flags and their
accessors/mutators can be removed.
"mm: store zero pages to be swapped out in a bitmap" from Usama Arif. An
optimization which permits us to avoid writing/reading zero-filled zswap
pages to backing store.
"Avoid MAP_FIXED gap exposure" from Liam Howlett. Fixes a race window
which occurs when a MAP_FIXED operqtion is occurring during an unrelated
vma tree walk.
"mm: remove vma_merge()" from Lorenzo Stoakes. Major rotorooting of the
vma_merge() functionality, making ot cleaner, more testable and better
tested.
"misc fixups for DAMON {self,kunit} tests" from SeongJae Park. Minor
fixups of DAMON selftests and kunit tests.
"mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang. Code
cleanups and folio conversions.
"Shmem mTHP controls and stats improvements" from Ryan Roberts. Cleanups
for shmem controls and stats.
"mm: count the number of anonymous THPs per size" from Barry Song. Expose
additional anon THP stats to userspace for improved tuning.
"mm: finish isolate/putback_lru_page()" from Kefeng Wang: more folio
conversions and removal of now-unused page-based APIs.
"replace per-quota region priorities histogram buffer with per-context
one" from SeongJae Park. DAMON histogram rationalization.
"Docs/damon: update GitHub repo URLs and maintainer-profile" from SeongJae
Park. DAMON documentation updates.
"mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and improve
related doc and warn" from Jason Wang: fixes usage of page allocator
__GFP_NOFAIL and GFP_ATOMIC flags.
"mm: split underused THPs" from Yu Zhao. Improve THP=always policy - this
was overprovisioning THPs in sparsely accessed memory areas.
"zram: introduce custom comp backends API" frm Sergey Senozhatsky. Add
support for zram run-time compression algorithm tuning.
"mm: Care about shadow stack guard gap when getting an unmapped area" from
Mark Brown. Fix up the various arch_get_unmapped_area() implementations
to better respect guard areas.
"Improve mem_cgroup_iter()" from Kinsey Ho. Improve the reliability of
mem_cgroup_iter() and various code cleanups.
"mm: Support huge pfnmaps" from Peter Xu. Extends the usage of huge
pfnmap support.
"resource: Fix region_intersects() vs add_memory_driver_managed()" from
Huang Ying. Fix a bug in region_intersects() for systems with CXL memory.
"mm: hwpoison: two more poison recovery" from Kefeng Wang. Teaches a
couple more code paths to correctly recover from the encountering of
poisoned memry.
"mm: enable large folios swap-in support" from Barry Song. Support the
swapin of mTHP memory into appropriately-sized folios, rather than into
single-page folios.
-----BEGIN PGP SIGNATURE-----
iHUEABYIAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCZu1BBwAKCRDdBJ7gKXxA
jlWNAQDYlqQLun7bgsAN4sSvi27VUuWv1q70jlMXTfmjJAvQqwD/fBFVR6IOOiw7
AkDbKWP2k0hWPiNJBGwoqxdHHx09Xgo=
=s0T+
-----END PGP SIGNATURE-----
Merge tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
"Along with the usual shower of singleton patches, notable patch series
in this pull request are:
- "Align kvrealloc() with krealloc()" from Danilo Krummrich. Adds
consistency to the APIs and behaviour of these two core allocation
functions. This also simplifies/enables Rustification.
- "Some cleanups for shmem" from Baolin Wang. No functional changes -
mode code reuse, better function naming, logic simplifications.
- "mm: some small page fault cleanups" from Josef Bacik. No
functional changes - code cleanups only.
- "Various memory tiering fixes" from Zi Yan. A small fix and a
little cleanup.
- "mm/swap: remove boilerplate" from Yu Zhao. Code cleanups and
simplifications and .text shrinkage.
- "Kernel stack usage histogram" from Pasha Tatashin and Shakeel
Butt. This is a feature, it adds new feilds to /proc/vmstat such as
$ grep kstack /proc/vmstat
kstack_1k 3
kstack_2k 188
kstack_4k 11391
kstack_8k 243
kstack_16k 0
which tells us that 11391 processes used 4k of stack while none at
all used 16k. Useful for some system tuning things, but
partivularly useful for "the dynamic kernel stack project".
- "kmemleak: support for percpu memory leak detect" from Pavel
Tikhomirov. Teaches kmemleak to detect leaksage of percpu memory.
- "mm: memcg: page counters optimizations" from Roman Gushchin. "3
independent small optimizations of page counters".
- "mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from
David Hildenbrand. Improves PTE/PMD splitlock detection, makes
powerpc/8xx work correctly by design rather than by accident.
- "mm: remove arch_make_page_accessible()" from David Hildenbrand.
Some folio conversions which make arch_make_page_accessible()
unneeded.
- "mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David
Finkel. Cleans up and fixes our handling of the resetting of the
cgroup/process peak-memory-use detector.
- "Make core VMA operations internal and testable" from Lorenzo
Stoakes. Rationalizaion and encapsulation of the VMA manipulation
APIs. With a view to better enable testing of the VMA functions,
even from a userspace-only harness.
- "mm: zswap: fixes for global shrinker" from Takero Funaki. Fix
issues in the zswap global shrinker, resulting in improved
performance.
- "mm: print the promo watermark in zoneinfo" from Kaiyang Zhao. Fill
in some missing info in /proc/zoneinfo.
- "mm: replace follow_page() by folio_walk" from David Hildenbrand.
Code cleanups and rationalizations (conversion to folio_walk())
resulting in the removal of follow_page().
- "improving dynamic zswap shrinker protection scheme" from Nhat
Pham. Some tuning to improve zswap's dynamic shrinker. Significant
reductions in swapin and improvements in performance are shown.
- "mm: Fix several issues with unaccepted memory" from Kirill
Shutemov. Improvements to the new unaccepted memory feature,
- "mm/mprotect: Fix dax puds" from Peter Xu. Implements mprotect on
DAX PUDs. This was missing, although nobody seems to have notied
yet.
- "Introduce a store type enum for the Maple tree" from Sidhartha
Kumar. Cleanups and modest performance improvements for the maple
tree library code.
- "memcg: further decouple v1 code from v2" from Shakeel Butt. Move
more cgroup v1 remnants away from the v2 memcg code.
- "memcg: initiate deprecation of v1 features" from Shakeel Butt.
Adds various warnings telling users that memcg v1 features are
deprecated.
- "mm: swap: mTHP swap allocator base on swap cluster order" from
Chris Li. Greatly improves the success rate of the mTHP swap
allocation.
- "mm: introduce numa_memblks" from Mike Rapoport. Moves various
disparate per-arch implementations of numa_memblk code into generic
code.
- "mm: batch free swaps for zap_pte_range()" from Barry Song. Greatly
improves the performance of munmap() of swap-filled ptes.
- "support large folio swap-out and swap-in for shmem" from Baolin
Wang. With this series we no longer split shmem large folios into
simgle-page folios when swapping out shmem.
- "mm/hugetlb: alloc/free gigantic folios" from Yu Zhao. Nice
performance improvements and code reductions for gigantic folios.
- "support shmem mTHP collapse" from Baolin Wang. Adds support for
khugepaged's collapsing of shmem mTHP folios.
- "mm: Optimize mseal checks" from Pedro Falcato. Fixes an mprotect()
performance regression due to the addition of mseal().
- "Increase the number of bits available in page_type" from Matthew
Wilcox. Increases the number of bits available in page_type!
- "Simplify the page flags a little" from Matthew Wilcox. Many legacy
page flags are now folio flags, so the page-based flags and their
accessors/mutators can be removed.
- "mm: store zero pages to be swapped out in a bitmap" from Usama
Arif. An optimization which permits us to avoid writing/reading
zero-filled zswap pages to backing store.
- "Avoid MAP_FIXED gap exposure" from Liam Howlett. Fixes a race
window which occurs when a MAP_FIXED operqtion is occurring during
an unrelated vma tree walk.
- "mm: remove vma_merge()" from Lorenzo Stoakes. Major rotorooting of
the vma_merge() functionality, making ot cleaner, more testable and
better tested.
- "misc fixups for DAMON {self,kunit} tests" from SeongJae Park.
Minor fixups of DAMON selftests and kunit tests.
- "mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang.
Code cleanups and folio conversions.
- "Shmem mTHP controls and stats improvements" from Ryan Roberts.
Cleanups for shmem controls and stats.
- "mm: count the number of anonymous THPs per size" from Barry Song.
Expose additional anon THP stats to userspace for improved tuning.
- "mm: finish isolate/putback_lru_page()" from Kefeng Wang: more
folio conversions and removal of now-unused page-based APIs.
- "replace per-quota region priorities histogram buffer with
per-context one" from SeongJae Park. DAMON histogram
rationalization.
- "Docs/damon: update GitHub repo URLs and maintainer-profile" from
SeongJae Park. DAMON documentation updates.
- "mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and
improve related doc and warn" from Jason Wang: fixes usage of page
allocator __GFP_NOFAIL and GFP_ATOMIC flags.
- "mm: split underused THPs" from Yu Zhao. Improve THP=always policy.
This was overprovisioning THPs in sparsely accessed memory areas.
- "zram: introduce custom comp backends API" frm Sergey Senozhatsky.
Add support for zram run-time compression algorithm tuning.
- "mm: Care about shadow stack guard gap when getting an unmapped
area" from Mark Brown. Fix up the various arch_get_unmapped_area()
implementations to better respect guard areas.
- "Improve mem_cgroup_iter()" from Kinsey Ho. Improve the reliability
of mem_cgroup_iter() and various code cleanups.
- "mm: Support huge pfnmaps" from Peter Xu. Extends the usage of huge
pfnmap support.
- "resource: Fix region_intersects() vs add_memory_driver_managed()"
from Huang Ying. Fix a bug in region_intersects() for systems with
CXL memory.
- "mm: hwpoison: two more poison recovery" from Kefeng Wang. Teaches
a couple more code paths to correctly recover from the encountering
of poisoned memry.
- "mm: enable large folios swap-in support" from Barry Song. Support
the swapin of mTHP memory into appropriately-sized folios, rather
than into single-page folios"
* tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (416 commits)
zram: free secondary algorithms names
uprobes: turn xol_area->pages[2] into xol_area->page
uprobes: introduce the global struct vm_special_mapping xol_mapping
Revert "uprobes: use vm_special_mapping close() functionality"
mm: support large folios swap-in for sync io devices
mm: add nr argument in mem_cgroup_swapin_uncharge_swap() helper to support large folios
mm: fix swap_read_folio_zeromap() for large folios with partial zeromap
mm/debug_vm_pgtable: Use pxdp_get() for accessing page table entries
set_memory: add __must_check to generic stubs
mm/vma: return the exact errno in vms_gather_munmap_vmas()
memcg: cleanup with !CONFIG_MEMCG_V1
mm/show_mem.c: report alloc tags in human readable units
mm: support poison recovery from copy_present_page()
mm: support poison recovery from do_cow_fault()
resource, kunit: add test case for region_intersects()
resource: make alloc_free_mem_region() works for iomem_resource
mm: z3fold: deprecate CONFIG_Z3FOLD
vfio/pci: implement huge_fault support
mm/arm64: support large pfn mappings
mm/x86: support large pfn mappings
...
* kvm-arm64/nv-at-pan:
: .
: Add NV support for the AT family of instructions, which mostly results
: in adding a page table walker that deals with most of the complexity
: of the architecture.
:
: From the cover letter:
:
: "Another task that a hypervisor supporting NV on arm64 has to deal with
: is to emulate the AT instruction, because we multiplex all the S1
: translations on a single set of registers, and the guest S2 is never
: truly resident on the CPU.
:
: So given that we lie about page tables, we also have to lie about
: translation instructions, hence the emulation. Things are made
: complicated by the fact that guest S1 page tables can be swapped out,
: and that our shadow S2 is likely to be incomplete. So while using AT
: to emulate AT is tempting (and useful), it is not going to always
: work, and we thus need a fallback in the shape of a SW S1 walker."
: .
KVM: arm64: nv: Add support for FEAT_ATS1A
KVM: arm64: nv: Plumb handling of AT S1* traps from EL2
KVM: arm64: nv: Make AT+PAN instructions aware of FEAT_PAN3
KVM: arm64: nv: Sanitise SCTLR_EL1.EPAN according to VM configuration
KVM: arm64: nv: Add SW walker for AT S1 emulation
KVM: arm64: nv: Make ps_to_output_size() generally available
KVM: arm64: nv: Add emulation of AT S12E{0,1}{R,W}
KVM: arm64: nv: Add basic emulation of AT S1E2{R,W}
KVM: arm64: nv: Add basic emulation of AT S1E1{R,W}P
KVM: arm64: nv: Add basic emulation of AT S1E{0,1}{R,W}
KVM: arm64: nv: Honor absence of FEAT_PAN2
KVM: arm64: nv: Turn upper_attr for S2 walk into the full descriptor
KVM: arm64: nv: Enforce S2 alignment when contiguous bit is set
arm64: Add ESR_ELx_FSC_ADDRSZ_L() helper
arm64: Add system register encoding for PSTATE.PAN
arm64: Add PAR_EL1 field description
arm64: Add missing APTable and TCR_ELx.HPD masks
KVM: arm64: Make kvm_at() take an OP_AT_*
Signed-off-by: Marc Zyngier <maz@kernel.org>
# Conflicts:
# arch/arm64/kvm/nested.c
Besides the obvious (and desired) difference between krealloc() and
kvrealloc(), there is some inconsistency in their function signatures and
behavior:
- krealloc() frees the memory when the requested size is zero, whereas
kvrealloc() simply returns a pointer to the existing allocation.
- krealloc() behaves like kmalloc() if a NULL pointer is passed, whereas
kvrealloc() does not accept a NULL pointer at all and, if passed,
would fault instead.
- krealloc() is self-contained, whereas kvrealloc() relies on the caller
to provide the size of the previous allocation.
Inconsistent behavior throughout allocation APIs is error prone, hence
make kvrealloc() behave like krealloc(), which seems superior in all
mentioned aspects.
Besides that, implementing kvrealloc() by making use of krealloc() and
vrealloc() provides oppertunities to grow (and shrink) allocations more
efficiently. For instance, vrealloc() can be optimized to allocate and
map additional pages to grow the allocation or unmap and free unused pages
to shrink the allocation.
[dakr@kernel.org: document concurrency restrictions]
Link: https://lkml.kernel.org/r/20240725125442.4957-1-dakr@kernel.org
[dakr@kernel.org: disable KASAN when switching to vmalloc]
Link: https://lkml.kernel.org/r/20240730185049.6244-2-dakr@kernel.org
[dakr@kernel.org: properly document __GFP_ZERO behavior]
Link: https://lkml.kernel.org/r/20240730185049.6244-5-dakr@kernel.org
Link: https://lkml.kernel.org/r/20240722163111.4766-3-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: Wedson Almeida Filho <wedsonaf@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The upper_attr attribute has been badly named, as it most of the
time carries the full "last walked descriptor".
Rename it to "desc" and make ti contain the full 64bit descriptor.
This will be used by the S1 PTW.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Despite KVM not using the contiguous bit for anything related to
TLBs, the spec does require that the alignment defined by the
contiguous bit for the page size and the level is enforced.
Add the required checks to offset the point where PA and VA merge.
Fixes: 61e30b9eef ("KVM: arm64: nv: Implement nested Stage-2 page table walk logic")
Reported-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
We already have to perform a set of last-chance adjustments for
NV purposes. We will soon have to do the same for the GIC, so
introduce a helper for that exact purpose.
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240827152517.3909653-5-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
kvm->arch.nested_mmus is allocated with kvrealloc(), hence free it with
kvfree() instead of kfree().
Fixes: 4f128f8e1a ("KVM: arm64: nv: Support multiple nested Stage-2 mmu structures")
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240723142204.758796-1-dakr@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
* kvm-arm64/nv-sve:
: CPTR_EL2, FPSIMD/SVE support for nested
:
: This series brings support for honoring the guest hypervisor's CPTR_EL2
: trap configuration when running a nested guest, along with support for
: FPSIMD/SVE usage at L1 and L2.
KVM: arm64: Allow the use of SVE+NV
KVM: arm64: nv: Add additional trap setup for CPTR_EL2
KVM: arm64: nv: Add trap description for CPTR_EL2
KVM: arm64: nv: Add TCPAC/TTA to CPTR->CPACR conversion helper
KVM: arm64: nv: Honor guest hypervisor's FP/SVE traps in CPTR_EL2
KVM: arm64: nv: Load guest FP state for ZCR_EL2 trap
KVM: arm64: nv: Handle CPACR_EL1 traps
KVM: arm64: Spin off helper for programming CPTR traps
KVM: arm64: nv: Ensure correct VL is loaded before saving SVE state
KVM: arm64: nv: Use guest hypervisor's max VL when running nested guest
KVM: arm64: nv: Save guest's ZCR_EL2 when in hyp context
KVM: arm64: nv: Load guest hyp's ZCR into EL1 state
KVM: arm64: nv: Handle ZCR_EL2 traps
KVM: arm64: nv: Forward SVE traps to guest hypervisor
KVM: arm64: nv: Forward FP/ASIMD traps to guest hypervisor
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
* kvm-arm64/ctr-el0:
: Support for user changes to CTR_EL0, courtesy of Sebastian Ott
:
: Allow userspace to change the guest-visible value of CTR_EL0 for a VM,
: so long as the requested value represents a subset of features supported
: by hardware. In other words, prevent the VMM from over-promising the
: capabilities of hardware.
:
: Make this happen by fitting CTR_EL0 into the existing infrastructure for
: feature ID registers.
KVM: selftests: Assert that MPIDR_EL1 is unchanged across vCPU reset
KVM: arm64: nv: Unfudge ID_AA64PFR0_EL1 masking
KVM: selftests: arm64: Test writes to CTR_EL0
KVM: arm64: rename functions for invariant sys regs
KVM: arm64: show writable masks for feature registers
KVM: arm64: Treat CTR_EL0 as a VM feature ID register
KVM: arm64: unify code to prepare traps
KVM: arm64: nv: Use accessors for modifying ID registers
KVM: arm64: Add helper for writing ID regs
KVM: arm64: Use read-only helper for reading VM ID registers
KVM: arm64: Make idregs debugfs iterator search sysreg table directly
KVM: arm64: Get sys_reg encoding from descriptor in idregs_debug_show()
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
* kvm-arm64/shadow-mmu:
: Shadow stage-2 MMU support for NV, courtesy of Marc Zyngier
:
: Initial implementation of shadow stage-2 page tables to support a guest
: hypervisor. In the author's words:
:
: So here's the 10000m (approximately 30000ft for those of you stuck
: with the wrong units) view of what this is doing:
:
: - for each {VMID,VTTBR,VTCR} tuple the guest uses, we use a
: separate shadow s2_mmu context. This context has its own "real"
: VMID and a set of page tables that are the combination of the
: guest's S2 and the host S2, built dynamically one fault at a time.
:
: - these shadow S2 contexts are ephemeral, and behave exactly as
: TLBs. For all intent and purposes, they *are* TLBs, and we discard
: them pretty often.
:
: - TLB invalidation takes three possible paths:
:
: * either this is an EL2 S1 invalidation, and we directly emulate
: it as early as possible
:
: * or this is an EL1 S1 invalidation, and we need to apply it to
: the shadow S2s (plural!) that match the VMID set by the L1 guest
:
: * or finally, this is affecting S2, and we need to teardown the
: corresponding part of the shadow S2s, which invalidates the TLBs
KVM: arm64: nv: Truely enable nXS TLBI operations
KVM: arm64: nv: Add handling of NXS-flavoured TLBI operations
KVM: arm64: nv: Add handling of range-based TLBI operations
KVM: arm64: nv: Add handling of outer-shareable TLBI operations
KVM: arm64: nv: Invalidate TLBs based on shadow S2 TTL-like information
KVM: arm64: nv: Tag shadow S2 entries with guest's leaf S2 level
KVM: arm64: nv: Handle FEAT_TTL hinted TLB operations
KVM: arm64: nv: Handle TLBI IPAS2E1{,IS} operations
KVM: arm64: nv: Handle TLBI ALLE1{,IS} operations
KVM: arm64: nv: Handle TLBI VMALLS12E1{,IS} operations
KVM: arm64: nv: Handle TLB invalidation targeting L2 stage-1
KVM: arm64: nv: Handle EL2 Stage-1 TLB invalidation
KVM: arm64: nv: Add Stage-1 EL2 invalidation primitives
KVM: arm64: nv: Unmap/flush shadow stage 2 page tables
KVM: arm64: nv: Handle shadow stage 2 page faults
KVM: arm64: nv: Implement nested Stage-2 page table walk logic
KVM: arm64: nv: Support multiple nested Stage-2 mmu structures
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This reverts commit eb9d53d4a9.
As Marc pointed out on the list [*], this patch is wrong, and those who
find themselves in the SOB chain should have their heads checked.
Annoyingly, the architecture has some FGT trap bits that are negative
(i.e. 0 implies trap), and there was some confusion how KVM handles
this for nested guests. However, it is clear now that KVM honors the
RES0-ness of FGT traps already, meaning traps for features never exposed
to the guest hypervisor get handled at L0. As they should.
Link: https://lore.kernel.org/kvmarm/86bk3c3uss.wl-maz@kernel.org/T/#mb9abb3dd79f6a4544a91cb35676bd637c3a5e836
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Although we now have support for nXS-flavoured TLBI instructions,
we still don't expose the feature to the guest thanks to a mixture
of misleading comment and use of a bunch of magic values.
Fix the comment and correctly express the masking of LS64, which
is enough to expose nXS to the world. Not that anyone cares...
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240703154743.824824-1-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Marc reports that L1 VMs aren't booting with the NV series applied to
today's kvmarm/next. After bisecting the issue, it appears that
44241f34fa ("KVM: arm64: nv: Use accessors for modifying ID
registers") is to blame.
Poking around at the issue a bit further, it'd appear that the value for
ID_AA64PFR0_EL1 is complete garbage, as 'val' still contains the value
we set ID_AA64ISAR1_EL1 to.
Fix the read-modify-write pattern to actually use ID_AA64PFR0_EL1 as the
starting point. Excuse me as I return to my shame cube.
Reported-by: Marc Zyngier <maz@kernel.org>
Fixes: 44241f34fa ("KVM: arm64: nv: Use accessors for modifying ID registers")
Acked-by: Marc Zyngier <maz@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240621224044.2465901-1-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
In the interest of abstracting away the underlying storage of feature
ID registers, rework the nested code to go through the accessors instead
of directly iterating the id_regs array.
This means we now lose the property that ID registers unknown to the
nested code get zeroed, but we really ought to be handling those
explicitly going forward.
Link: https://lore.kernel.org/r/20240619174036.483943-6-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Replace the remaining usage of IDREG() with a new helper for setting the
value of a feature ID register, with the benefit of cramming in some
extra sanity checks.
Reviewed-by: Sebastian Ott <sebott@redhat.com>
Link: https://lore.kernel.org/r/20240619174036.483943-5-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Of course, userspace is in the driver's seat for struct kvm and
associated allocations. Make sure the sysreg_masks allocation
participates in kmem accounting.
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240617181018.2054332-1-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
We already support some form of range operation by handling FEAT_TTL,
but so far the "arbitrary" range operations are unsupported.
Let's fix that.
For EL2 S1, this is simple enough: we just map both NSH, ISH and OSH
instructions onto the ISH version for EL1.
For TLBI instructions affecting EL1 S1, we use the same model as
their non-range counterpart to invalidate in the context of the
correct VMID.
For TLBI instructions affecting S2, we interpret the data passed
by the guest to compute the range and use that to tear-down part
of the shadow S2 range and invalidate the TLBs.
Finally, we advertise FEAT_TLBIRANGE if the host supports it.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-16-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Our handling of outer-shareable TLBIs is pretty basic: we just
map them to the existing inner-shareable ones, because we really
don't have anything else.
The only significant change is that we can now advertise FEAT_TLBIOS
support if the host supports it.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-15-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
In order to be able to make S2 TLB invalidations more performant on NV,
let's use a scheme derived from the FEAT_TTL extension.
If bits [56:55] in the leaf descriptor translating the address in the
corresponding shadow S2 are non-zero, they indicate a level which can
be used as an invalidation range. This allows further reduction of the
systematic over-invalidation that takes place otherwise.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-14-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Support guest-provided information information to size the range of
required invalidation. This helps with reducing over-invalidation,
provided that the guest actually provides accurate information.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-12-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
While dealing with TLB invalidation targeting the guest hypervisor's
own stage-1 was easy, doing the same thing for its own guests is
a bit more involved.
Since such an invalidation is scoped by VMID, it needs to apply to
all s2_mmu contexts that have been tagged by that VMID, irrespective
of the value of VTTBR_EL2.BADDR.
So for each s2_mmu context matching that VMID, we invalidate the
corresponding TLBs, each context having its own "physical" VMID.
Co-developed-by: Jintack Lim <jintack.lim@linaro.org>
Co-developed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-8-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Unmap/flush shadow stage 2 page tables for the nested VMs as well as the
stage 2 page table for the guest hypervisor.
Note: A bunch of the code in mmu.c relating to MMU notifiers is
currently dealt with in an extremely abrupt way, for example by clearing
out an entire shadow stage-2 table. This will be handled in a more
efficient way using the reverse mapping feature in a later version of
the patch series.
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-5-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
If we are faulting on a shadow stage 2 translation, we first walk the
guest hypervisor's stage 2 page table to see if it has a mapping. If
not, we inject a stage 2 page fault to the virtual EL2. Otherwise, we
create a mapping in the shadow stage 2 page table.
Note that we have to deal with two IPAs when we got a shadow stage 2
page fault. One is the address we faulted on, and is in the L2 guest
phys space. The other is from the guest stage-2 page table walk, and is
in the L1 guest phys space. To differentiate them, we rename variables
so that fault_ipa is used for the former and ipa is used for the latter.
When mapping a page in a shadow stage-2, special care must be taken not
to be more permissive than the guest is.
Co-developed-by: Christoffer Dall <christoffer.dall@linaro.org>
Co-developed-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-4-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Based on the pseudo-code in the ARM ARM, implement a stage 2 software
page table walker.
Co-developed-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-3-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Add Stage-2 mmu data structures for virtual EL2 and for nested guests.
We don't yet populate shadow Stage-2 page tables, but we now have a
framework for getting to a shadow Stage-2 pgd.
We allocate twice the number of vcpus as Stage-2 mmu structures because
that's sufficient for each vcpu running two translation regimes without
having to flush the Stage-2 page tables.
Co-developed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-2-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
The Fine Grained Trap extension is pretty messy as it doesn't
consistently use the same polarity for all trap bits. A bunch
of them, added later in the life of the architecture, have a
*negative* priority.
So if these bits are disabled, they must be RES1 and not RES0.
But that's not what the code implements, making the traps for
these negative trap bits being always on instead of disabled.
Fix the relevant bits, and stick a brown paper bag on my head
for the rest of the day...
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614125858.78361-1-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Now that we expose PAC to NV guests, we can also expose BTI (as
the two as joined at the hip, due to some of the PAC instructions
being landing pads).
While we're at it, also propagate CSV_frac, which requires no
particular emulation.
Fixes: f4f6a95bac ("KVM: arm64: nv: Advertise support for PAuth")
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240528100632.1831995-3-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Now that we (hopefully) correctly handle ERETAx, drop the masking
of the PAuth feature (something that was not even complete, as
APA3 and AGA3 were still exposed).
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240419102935.1935571-15-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Just like its little friends, HCRX_EL2 gets the feature set treatment
when backed by VNCR.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240214131827.2856277-7-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Fine Grained Traps are controlled by a whole bunch of features.
Each one of them must be checked and the corresponding masks
computed so that we don't let the guest apply traps it shouldn't
be using.
This takes care of HFG[IRW]TR_EL2, HDFG[RW]TR_EL2, and HAFGRTR_EL2.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Link: https://lore.kernel.org/r/20240214131827.2856277-6-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
We can now start making use of our sanitising masks by setting them
to values that depend on the guest's configuration.
First up are VTTBR_EL2, VTCR_EL2, VMPIDR_EL2 and HCR_EL2.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240214131827.2856277-5-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
VNCR-backed "registers" are actually only memory. Which means that
there is zero control over what the guest can write, and that it
is the hypervisor's job to actually sanitise the content of the
backing store. Yeah, this is fun.
In order to preserve some form of sanity, add a repainting mechanism
that makes use of a per-VM set of RES0/RES1 masks, one pair per VNCR
register. These masks get applied on access to the backing store via
__vcpu_sys_reg(), ensuring that the state that is consumed by KVM is
correct.
So far, nothing populates these masks, but stay tuned.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Link: https://lore.kernel.org/r/20240214131827.2856277-4-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
We can now expose ID_AA64MMFR4_EL1 to guests, and let NV guests
understand that they cannot really switch HCR_EL2.E2H to 0 on
some platforms.
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240122181344.258974-9-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Now that we have a full copy of the idregs for each VM, there is
no point in repainting the sysregs on each access. Instead, we
can simply perform the transmation as a one-off and be done
with it.
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
HCRX_EL2 has an interesting effect on HFGITR_EL2, as it conditions
the traps of TLBI*nXS.
Expand the FGT support to add a new Fine Grained Filter that will
get checked when the instruction gets trapped, allowing the shadow
register to override the trap as needed.
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Jing Zhang <jingzhangos@google.com>
Link: https://lore.kernel.org/r/20230815183903.2735724-29-maz@kernel.org
Now that we have FGT support, expose the feature to NV guests.
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Jing Zhang <jingzhangos@google.com>
Link: https://lore.kernel.org/r/20230815183903.2735724-27-maz@kernel.org
Now that we properly implement FEAT_EVT (as we correctly forward
traps), expose it to guests.
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Jing Zhang <jingzhangos@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230815183903.2735724-17-maz@kernel.org
Avoid open-coding and just use the helper to encode the ID from the
sysreg table entry.
No functional change intended.
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230211190742.49843-1-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
As there is a number of features that we either can't support,
or don't want to support right away with NV, let's add some
basic filtering so that we don't advertize silly things to the
EL2 guest.
Whilst we are at it, advertize FEAT_TTL as well as FEAT_GTG, which
the NV implementation will implement.
Reviewed-by: Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230209175820.1939006-18-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
