<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/arch/arm64/include, branch v6.12</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge tag 'mm-hotfixes-stable-2024-11-09-22-40' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm</title>
<updated>2024-11-10T17:04:27+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-11-10T17:04:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=28e43197c4460e08b55554c05998d6de9da7d0b6'/>
<id>28e43197c4460e08b55554c05998d6de9da7d0b6</id>
<content type='text'>
Pull misc fixes from Andrew Morton:
 "20 hotfixes, 14 of which are cc:stable.

  Three affect DAMON. Lorenzo's five-patch series to address the
  mmap_region error handling is here also.

  Apart from that, various singletons"

* tag 'mm-hotfixes-stable-2024-11-09-22-40' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mailmap: add entry for Thorsten Blum
  ocfs2: remove entry once instead of null-ptr-dereference in ocfs2_xa_remove()
  signal: restore the override_rlimit logic
  fs/proc: fix compile warning about variable 'vmcore_mmap_ops'
  ucounts: fix counter leak in inc_rlimit_get_ucounts()
  selftests: hugetlb_dio: check for initial conditions to skip in the start
  mm: fix docs for the kernel parameter ``thp_anon=``
  mm/damon/core: avoid overflow in damon_feed_loop_next_input()
  mm/damon/core: handle zero schemes apply interval
  mm/damon/core: handle zero {aggregation,ops_update} intervals
  mm/mlock: set the correct prev on failure
  objpool: fix to make percpu slot allocation more robust
  mm/page_alloc: keep track of free highatomic
  mm: resolve faulty mmap_region() error path behaviour
  mm: refactor arch_calc_vm_flag_bits() and arm64 MTE handling
  mm: refactor map_deny_write_exec()
  mm: unconditionally close VMAs on error
  mm: avoid unsafe VMA hook invocation when error arises on mmap hook
  mm/thp: fix deferred split unqueue naming and locking
  mm/thp: fix deferred split queue not partially_mapped
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull misc fixes from Andrew Morton:
 "20 hotfixes, 14 of which are cc:stable.

  Three affect DAMON. Lorenzo's five-patch series to address the
  mmap_region error handling is here also.

  Apart from that, various singletons"

* tag 'mm-hotfixes-stable-2024-11-09-22-40' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mailmap: add entry for Thorsten Blum
  ocfs2: remove entry once instead of null-ptr-dereference in ocfs2_xa_remove()
  signal: restore the override_rlimit logic
  fs/proc: fix compile warning about variable 'vmcore_mmap_ops'
  ucounts: fix counter leak in inc_rlimit_get_ucounts()
  selftests: hugetlb_dio: check for initial conditions to skip in the start
  mm: fix docs for the kernel parameter ``thp_anon=``
  mm/damon/core: avoid overflow in damon_feed_loop_next_input()
  mm/damon/core: handle zero schemes apply interval
  mm/damon/core: handle zero {aggregation,ops_update} intervals
  mm/mlock: set the correct prev on failure
  objpool: fix to make percpu slot allocation more robust
  mm/page_alloc: keep track of free highatomic
  mm: resolve faulty mmap_region() error path behaviour
  mm: refactor arch_calc_vm_flag_bits() and arm64 MTE handling
  mm: refactor map_deny_write_exec()
  mm: unconditionally close VMAs on error
  mm: avoid unsafe VMA hook invocation when error arises on mmap hook
  mm/thp: fix deferred split unqueue naming and locking
  mm/thp: fix deferred split queue not partially_mapped
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI: processor: Move arch_init_invariance_cppc() call later</title>
<updated>2024-11-06T20:31:36+00:00</updated>
<author>
<name>Mario Limonciello</name>
<email>mario.limonciello@amd.com</email>
</author>
<published>2024-11-04T22:28:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=b79276dcac9124a79c8cf7cc8fbdd3d4c3c9a7c7'/>
<id>b79276dcac9124a79c8cf7cc8fbdd3d4c3c9a7c7</id>
<content type='text'>
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 21fb59ab4b97
("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 279f838a61f9 ("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: 279f838a61f9 ("x86/amd: Detect preferred cores in amd_get_boost_ratio_numerator()")
Reported-by: Ivan Shapovalov &lt;intelfx@intelfx.name&gt;
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219431
Tested-by: Oleksandr Natalenko &lt;oleksandr@natalenko.name&gt;
Signed-off-by: Mario Limonciello &lt;mario.limonciello@amd.com&gt;
Link: https://patch.msgid.link/20241104222855.3959267-1-superm1@kernel.org
[ rjw: Changelog edit ]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
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 21fb59ab4b97
("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 279f838a61f9 ("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: 279f838a61f9 ("x86/amd: Detect preferred cores in amd_get_boost_ratio_numerator()")
Reported-by: Ivan Shapovalov &lt;intelfx@intelfx.name&gt;
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219431
Tested-by: Oleksandr Natalenko &lt;oleksandr@natalenko.name&gt;
Signed-off-by: Mario Limonciello &lt;mario.limonciello@amd.com&gt;
Link: https://patch.msgid.link/20241104222855.3959267-1-superm1@kernel.org
[ rjw: Changelog edit ]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm: refactor arch_calc_vm_flag_bits() and arm64 MTE handling</title>
<updated>2024-11-06T00:49:55+00:00</updated>
<author>
<name>Lorenzo Stoakes</name>
<email>lorenzo.stoakes@oracle.com</email>
</author>
<published>2024-10-29T18:11:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=5baf8b037debf4ec60108ccfeccb8636d1dbad81'/>
<id>5baf8b037debf4ec60108ccfeccb8636d1dbad81</id>
<content type='text'>
Currently MTE is permitted in two circumstances (desiring to use MTE
having been specified by the VM_MTE flag) - where MAP_ANONYMOUS is
specified, as checked by arch_calc_vm_flag_bits() and actualised by
setting the VM_MTE_ALLOWED flag, or if the file backing the mapping is
shmem, in which case we set VM_MTE_ALLOWED in shmem_mmap() when the mmap
hook is activated in mmap_region().

The function that checks that, if VM_MTE is set, VM_MTE_ALLOWED is also
set is the arm64 implementation of arch_validate_flags().

Unfortunately, we intend to refactor mmap_region() to perform this check
earlier, meaning that in the case of a shmem backing we will not have
invoked shmem_mmap() yet, causing the mapping to fail spuriously.

It is inappropriate to set this architecture-specific flag in general mm
code anyway, so a sensible resolution of this issue is to instead move the
check somewhere else.

We resolve this by setting VM_MTE_ALLOWED much earlier in do_mmap(), via
the arch_calc_vm_flag_bits() call.

This is an appropriate place to do this as we already check for the
MAP_ANONYMOUS case here, and the shmem file case is simply a variant of
the same idea - we permit RAM-backed memory.

This requires a modification to the arch_calc_vm_flag_bits() signature to
pass in a pointer to the struct file associated with the mapping, however
this is not too egregious as this is only used by two architectures anyway
- arm64 and parisc.

So this patch performs this adjustment and removes the unnecessary
assignment of VM_MTE_ALLOWED in shmem_mmap().

[akpm@linux-foundation.org: fix whitespace, per Catalin]
Link: https://lkml.kernel.org/r/ec251b20ba1964fb64cf1607d2ad80c47f3873df.1730224667.git.lorenzo.stoakes@oracle.com
Fixes: deb0f6562884 ("mm/mmap: undo -&gt;mmap() when arch_validate_flags() fails")
Signed-off-by: Lorenzo Stoakes &lt;lorenzo.stoakes@oracle.com&gt;
Suggested-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Reported-by: Jann Horn &lt;jannh@google.com&gt;
Reviewed-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Reviewed-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: Andreas Larsson &lt;andreas@gaisler.com&gt;
Cc: David S. Miller &lt;davem@davemloft.net&gt;
Cc: Helge Deller &lt;deller@gmx.de&gt;
Cc: James E.J. Bottomley &lt;James.Bottomley@HansenPartnership.com&gt;
Cc: Liam R. Howlett &lt;Liam.Howlett@oracle.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Mark Brown &lt;broonie@kernel.org&gt;
Cc: Peter Xu &lt;peterx@redhat.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently MTE is permitted in two circumstances (desiring to use MTE
having been specified by the VM_MTE flag) - where MAP_ANONYMOUS is
specified, as checked by arch_calc_vm_flag_bits() and actualised by
setting the VM_MTE_ALLOWED flag, or if the file backing the mapping is
shmem, in which case we set VM_MTE_ALLOWED in shmem_mmap() when the mmap
hook is activated in mmap_region().

The function that checks that, if VM_MTE is set, VM_MTE_ALLOWED is also
set is the arm64 implementation of arch_validate_flags().

Unfortunately, we intend to refactor mmap_region() to perform this check
earlier, meaning that in the case of a shmem backing we will not have
invoked shmem_mmap() yet, causing the mapping to fail spuriously.

It is inappropriate to set this architecture-specific flag in general mm
code anyway, so a sensible resolution of this issue is to instead move the
check somewhere else.

We resolve this by setting VM_MTE_ALLOWED much earlier in do_mmap(), via
the arch_calc_vm_flag_bits() call.

This is an appropriate place to do this as we already check for the
MAP_ANONYMOUS case here, and the shmem file case is simply a variant of
the same idea - we permit RAM-backed memory.

This requires a modification to the arch_calc_vm_flag_bits() signature to
pass in a pointer to the struct file associated with the mapping, however
this is not too egregious as this is only used by two architectures anyway
- arm64 and parisc.

So this patch performs this adjustment and removes the unnecessary
assignment of VM_MTE_ALLOWED in shmem_mmap().

[akpm@linux-foundation.org: fix whitespace, per Catalin]
Link: https://lkml.kernel.org/r/ec251b20ba1964fb64cf1607d2ad80c47f3873df.1730224667.git.lorenzo.stoakes@oracle.com
Fixes: deb0f6562884 ("mm/mmap: undo -&gt;mmap() when arch_validate_flags() fails")
Signed-off-by: Lorenzo Stoakes &lt;lorenzo.stoakes@oracle.com&gt;
Suggested-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Reported-by: Jann Horn &lt;jannh@google.com&gt;
Reviewed-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Reviewed-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: Andreas Larsson &lt;andreas@gaisler.com&gt;
Cc: David S. Miller &lt;davem@davemloft.net&gt;
Cc: Helge Deller &lt;deller@gmx.de&gt;
Cc: James E.J. Bottomley &lt;James.Bottomley@HansenPartnership.com&gt;
Cc: Liam R. Howlett &lt;Liam.Howlett@oracle.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Mark Brown &lt;broonie@kernel.org&gt;
Cc: Peter Xu &lt;peterx@redhat.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm</title>
<updated>2024-10-21T18:22:04+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-10-21T18:22:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=d129377639907fce7e0a27990e590e4661d3ee02'/>
<id>d129377639907fce7e0a27990e590e4661d3ee02</id>
<content type='text'>
Pull kvm fixes from Paolo Bonzini:
 "ARM64:

   - Fix the guest view of the ID registers, making the relevant fields
     writable from userspace (affecting ID_AA64DFR0_EL1 and
     ID_AA64PFR1_EL1)

   - Correcly expose S1PIE to guests, fixing a regression introduced in
     6.12-rc1 with the S1POE support

   - Fix the recycling of stage-2 shadow MMUs by tracking the context
     (are we allowed to block or not) as well as the recycling state

   - Address a couple of issues with the vgic when userspace
     misconfigures the emulation, resulting in various splats. Headaches
     courtesy of our Syzkaller friends

   - Stop wasting space in the HYP idmap, as we are dangerously close to
     the 4kB limit, and this has already exploded in -next

   - Fix another race in vgic_init()

   - Fix a UBSAN error when faking the cache topology with MTE enabled

  RISCV:

   - RISCV: KVM: use raw_spinlock for critical section in imsic

  x86:

   - A bandaid for lack of XCR0 setup in selftests, which causes trouble
     if the compiler is configured to have x86-64-v3 (with AVX) as the
     default ISA. Proper XCR0 setup will come in the next merge window.

   - Fix an issue where KVM would not ignore low bits of the nested CR3
     and potentially leak up to 31 bytes out of the guest memory's
     bounds

   - Fix case in which an out-of-date cached value for the segments
     could by returned by KVM_GET_SREGS.

   - More cleanups for KVM_X86_QUIRK_SLOT_ZAP_ALL

   - Override MTRR state for KVM confidential guests, making it WB by
     default as is already the case for Hyper-V guests.

  Generic:

   - Remove a couple of unused functions"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (27 commits)
  RISCV: KVM: use raw_spinlock for critical section in imsic
  KVM: selftests: Fix out-of-bounds reads in CPUID test's array lookups
  KVM: selftests: x86: Avoid using SSE/AVX instructions
  KVM: nSVM: Ignore nCR3[4:0] when loading PDPTEs from memory
  KVM: VMX: reset the segment cache after segment init in vmx_vcpu_reset()
  KVM: x86: Clean up documentation for KVM_X86_QUIRK_SLOT_ZAP_ALL
  KVM: x86/mmu: Add lockdep assert to enforce safe usage of kvm_unmap_gfn_range()
  KVM: x86/mmu: Zap only SPs that shadow gPTEs when deleting memslot
  x86/kvm: Override default caching mode for SEV-SNP and TDX
  KVM: Remove unused kvm_vcpu_gfn_to_pfn_atomic
  KVM: Remove unused kvm_vcpu_gfn_to_pfn
  KVM: arm64: Ensure vgic_ready() is ordered against MMIO registration
  KVM: arm64: vgic: Don't check for vgic_ready() when setting NR_IRQS
  KVM: arm64: Fix shift-out-of-bounds bug
  KVM: arm64: Shave a few bytes from the EL2 idmap code
  KVM: arm64: Don't eagerly teardown the vgic on init error
  KVM: arm64: Expose S1PIE to guests
  KVM: arm64: nv: Clarify safety of allowing TLBI unmaps to reschedule
  KVM: arm64: nv: Punt stage-2 recycling to a vCPU request
  KVM: arm64: nv: Do not block when unmapping stage-2 if disallowed
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull kvm fixes from Paolo Bonzini:
 "ARM64:

   - Fix the guest view of the ID registers, making the relevant fields
     writable from userspace (affecting ID_AA64DFR0_EL1 and
     ID_AA64PFR1_EL1)

   - Correcly expose S1PIE to guests, fixing a regression introduced in
     6.12-rc1 with the S1POE support

   - Fix the recycling of stage-2 shadow MMUs by tracking the context
     (are we allowed to block or not) as well as the recycling state

   - Address a couple of issues with the vgic when userspace
     misconfigures the emulation, resulting in various splats. Headaches
     courtesy of our Syzkaller friends

   - Stop wasting space in the HYP idmap, as we are dangerously close to
     the 4kB limit, and this has already exploded in -next

   - Fix another race in vgic_init()

   - Fix a UBSAN error when faking the cache topology with MTE enabled

  RISCV:

   - RISCV: KVM: use raw_spinlock for critical section in imsic

  x86:

   - A bandaid for lack of XCR0 setup in selftests, which causes trouble
     if the compiler is configured to have x86-64-v3 (with AVX) as the
     default ISA. Proper XCR0 setup will come in the next merge window.

   - Fix an issue where KVM would not ignore low bits of the nested CR3
     and potentially leak up to 31 bytes out of the guest memory's
     bounds

   - Fix case in which an out-of-date cached value for the segments
     could by returned by KVM_GET_SREGS.

   - More cleanups for KVM_X86_QUIRK_SLOT_ZAP_ALL

   - Override MTRR state for KVM confidential guests, making it WB by
     default as is already the case for Hyper-V guests.

  Generic:

   - Remove a couple of unused functions"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (27 commits)
  RISCV: KVM: use raw_spinlock for critical section in imsic
  KVM: selftests: Fix out-of-bounds reads in CPUID test's array lookups
  KVM: selftests: x86: Avoid using SSE/AVX instructions
  KVM: nSVM: Ignore nCR3[4:0] when loading PDPTEs from memory
  KVM: VMX: reset the segment cache after segment init in vmx_vcpu_reset()
  KVM: x86: Clean up documentation for KVM_X86_QUIRK_SLOT_ZAP_ALL
  KVM: x86/mmu: Add lockdep assert to enforce safe usage of kvm_unmap_gfn_range()
  KVM: x86/mmu: Zap only SPs that shadow gPTEs when deleting memslot
  x86/kvm: Override default caching mode for SEV-SNP and TDX
  KVM: Remove unused kvm_vcpu_gfn_to_pfn_atomic
  KVM: Remove unused kvm_vcpu_gfn_to_pfn
  KVM: arm64: Ensure vgic_ready() is ordered against MMIO registration
  KVM: arm64: vgic: Don't check for vgic_ready() when setting NR_IRQS
  KVM: arm64: Fix shift-out-of-bounds bug
  KVM: arm64: Shave a few bytes from the EL2 idmap code
  KVM: arm64: Don't eagerly teardown the vgic on init error
  KVM: arm64: Expose S1PIE to guests
  KVM: arm64: nv: Clarify safety of allowing TLBI unmaps to reschedule
  KVM: arm64: nv: Punt stage-2 recycling to a vCPU request
  KVM: arm64: nv: Do not block when unmapping stage-2 if disallowed
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux</title>
<updated>2024-10-17T16:51:03+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-10-17T16:51:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=6efbea77b390604a7be7364583e19cd2d6a1291b'/>
<id>6efbea77b390604a7be7364583e19cd2d6a1291b</id>
<content type='text'>
Pull arm64 fixes from Will Deacon:

 - Disable software tag-based KASAN when compiling with GCC, as
   functions are incorrectly instrumented leading to a crash early
   during boot

 - Fix pkey configuration for kernel threads when POE is enabled

 - Fix invalid memory accesses in uprobes when targetting load-literal
   instructions

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  kasan: Disable Software Tag-Based KASAN with GCC
  Documentation/protection-keys: add AArch64 to documentation
  arm64: set POR_EL0 for kernel threads
  arm64: probes: Fix uprobes for big-endian kernels
  arm64: probes: Fix simulate_ldr*_literal()
  arm64: probes: Remove broken LDR (literal) uprobe support
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull arm64 fixes from Will Deacon:

 - Disable software tag-based KASAN when compiling with GCC, as
   functions are incorrectly instrumented leading to a crash early
   during boot

 - Fix pkey configuration for kernel threads when POE is enabled

 - Fix invalid memory accesses in uprobes when targetting load-literal
   instructions

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  kasan: Disable Software Tag-Based KASAN with GCC
  Documentation/protection-keys: add AArch64 to documentation
  arm64: set POR_EL0 for kernel threads
  arm64: probes: Fix uprobes for big-endian kernels
  arm64: probes: Fix simulate_ldr*_literal()
  arm64: probes: Remove broken LDR (literal) uprobe support
</pre>
</div>
</content>
</entry>
<entry>
<title>KVM: arm64: Shave a few bytes from the EL2 idmap code</title>
<updated>2024-10-17T08:17:56+00:00</updated>
<author>
<name>Marc Zyngier</name>
<email>maz@kernel.org</email>
</author>
<published>2024-10-10T15:13:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=afa9b48f327c9ef36bfba4c643a29385a633252b'/>
<id>afa9b48f327c9ef36bfba4c643a29385a633252b</id>
<content type='text'>
Our idmap is becoming too big, to the point where it doesn't fit in
a 4kB page anymore.

There are some low-hanging fruits though, such as the el2_init_state
horror that is expanded 3 times in the kernel. Let's at least limit
ourselves to two copies, which makes the kernel link again.

At some point, we'll have to have a better way of doing this.

Reported-by: Nathan Chancellor &lt;nathan@kernel.org&gt;
Signed-off-by: Marc Zyngier &lt;maz@kernel.org&gt;
Link: https://lore.kernel.org/r/20241009204903.GA3353168@thelio-3990X
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Our idmap is becoming too big, to the point where it doesn't fit in
a 4kB page anymore.

There are some low-hanging fruits though, such as the el2_init_state
horror that is expanded 3 times in the kernel. Let's at least limit
ourselves to two copies, which makes the kernel link again.

At some point, we'll have to have a better way of doing this.

Reported-by: Nathan Chancellor &lt;nathan@kernel.org&gt;
Signed-off-by: Marc Zyngier &lt;maz@kernel.org&gt;
Link: https://lore.kernel.org/r/20241009204903.GA3353168@thelio-3990X
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: probes: Fix uprobes for big-endian kernels</title>
<updated>2024-10-09T15:56:53+00:00</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2024-10-08T15:58:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=13f8f1e05f1dc36dbba6cba0ae03354c0dafcde7'/>
<id>13f8f1e05f1dc36dbba6cba0ae03354c0dafcde7</id>
<content type='text'>
The arm64 uprobes code is broken for big-endian kernels as it doesn't
convert the in-memory instruction encoding (which is always
little-endian) into the kernel's native endianness before analyzing and
simulating instructions. This may result in a few distinct problems:

* The kernel may may erroneously reject probing an instruction which can
  safely be probed.

* The kernel may erroneously erroneously permit stepping an
  instruction out-of-line when that instruction cannot be stepped
  out-of-line safely.

* The kernel may erroneously simulate instruction incorrectly dur to
  interpretting the byte-swapped encoding.

The endianness mismatch isn't caught by the compiler or sparse because:

* The arch_uprobe::{insn,ixol} fields are encoded as arrays of u8, so
  the compiler and sparse have no idea these contain a little-endian
  32-bit value. The core uprobes code populates these with a memcpy()
  which similarly does not handle endianness.

* While the uprobe_opcode_t type is an alias for __le32, both
  arch_uprobe_analyze_insn() and arch_uprobe_skip_sstep() cast from u8[]
  to the similarly-named probe_opcode_t, which is an alias for u32.
  Hence there is no endianness conversion warning.

Fix this by changing the arch_uprobe::{insn,ixol} fields to __le32 and
adding the appropriate __le32_to_cpu() conversions prior to consuming
the instruction encoding. The core uprobes copies these fields as opaque
ranges of bytes, and so is unaffected by this change.

At the same time, remove MAX_UINSN_BYTES and consistently use
AARCH64_INSN_SIZE for clarity.

Tested with the following:

| #include &lt;stdio.h&gt;
| #include &lt;stdbool.h&gt;
|
| #define noinline __attribute__((noinline))
|
| static noinline void *adrp_self(void)
| {
|         void *addr;
|
|         asm volatile(
|         "       adrp    %x0, adrp_self\n"
|         "       add     %x0, %x0, :lo12:adrp_self\n"
|         : "=r" (addr));
| }
|
|
| int main(int argc, char *argv)
| {
|         void *ptr = adrp_self();
|         bool equal = (ptr == adrp_self);
|
|         printf("adrp_self   =&gt; %p\n"
|                "adrp_self() =&gt; %p\n"
|                "%s\n",
|                adrp_self, ptr, equal ? "EQUAL" : "NOT EQUAL");
|
|         return 0;
| }

.... where the adrp_self() function was compiled to:

| 00000000004007e0 &lt;adrp_self&gt;:
|   4007e0:       90000000        adrp    x0, 400000 &lt;__ehdr_start&gt;
|   4007e4:       911f8000        add     x0, x0, #0x7e0
|   4007e8:       d65f03c0        ret

Before this patch, the ADRP is not recognized, and is assumed to be
steppable, resulting in corruption of the result:

| # ./adrp-self
| adrp_self   =&gt; 0x4007e0
| adrp_self() =&gt; 0x4007e0
| EQUAL
| # echo 'p /root/adrp-self:0x007e0' &gt; /sys/kernel/tracing/uprobe_events
| # echo 1 &gt; /sys/kernel/tracing/events/uprobes/enable
| # ./adrp-self
| adrp_self   =&gt; 0x4007e0
| adrp_self() =&gt; 0xffffffffff7e0
| NOT EQUAL

After this patch, the ADRP is correctly recognized and simulated:

| # ./adrp-self
| adrp_self   =&gt; 0x4007e0
| adrp_self() =&gt; 0x4007e0
| EQUAL
| #
| # echo 'p /root/adrp-self:0x007e0' &gt; /sys/kernel/tracing/uprobe_events
| # echo 1 &gt; /sys/kernel/tracing/events/uprobes/enable
| # ./adrp-self
| adrp_self   =&gt; 0x4007e0
| adrp_self() =&gt; 0x4007e0
| EQUAL

Fixes: 9842ceae9fa8 ("arm64: Add uprobe support")
Cc: stable@vger.kernel.org
Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20241008155851.801546-4-mark.rutland@arm.com
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The arm64 uprobes code is broken for big-endian kernels as it doesn't
convert the in-memory instruction encoding (which is always
little-endian) into the kernel's native endianness before analyzing and
simulating instructions. This may result in a few distinct problems:

* The kernel may may erroneously reject probing an instruction which can
  safely be probed.

* The kernel may erroneously erroneously permit stepping an
  instruction out-of-line when that instruction cannot be stepped
  out-of-line safely.

* The kernel may erroneously simulate instruction incorrectly dur to
  interpretting the byte-swapped encoding.

The endianness mismatch isn't caught by the compiler or sparse because:

* The arch_uprobe::{insn,ixol} fields are encoded as arrays of u8, so
  the compiler and sparse have no idea these contain a little-endian
  32-bit value. The core uprobes code populates these with a memcpy()
  which similarly does not handle endianness.

* While the uprobe_opcode_t type is an alias for __le32, both
  arch_uprobe_analyze_insn() and arch_uprobe_skip_sstep() cast from u8[]
  to the similarly-named probe_opcode_t, which is an alias for u32.
  Hence there is no endianness conversion warning.

Fix this by changing the arch_uprobe::{insn,ixol} fields to __le32 and
adding the appropriate __le32_to_cpu() conversions prior to consuming
the instruction encoding. The core uprobes copies these fields as opaque
ranges of bytes, and so is unaffected by this change.

At the same time, remove MAX_UINSN_BYTES and consistently use
AARCH64_INSN_SIZE for clarity.

Tested with the following:

| #include &lt;stdio.h&gt;
| #include &lt;stdbool.h&gt;
|
| #define noinline __attribute__((noinline))
|
| static noinline void *adrp_self(void)
| {
|         void *addr;
|
|         asm volatile(
|         "       adrp    %x0, adrp_self\n"
|         "       add     %x0, %x0, :lo12:adrp_self\n"
|         : "=r" (addr));
| }
|
|
| int main(int argc, char *argv)
| {
|         void *ptr = adrp_self();
|         bool equal = (ptr == adrp_self);
|
|         printf("adrp_self   =&gt; %p\n"
|                "adrp_self() =&gt; %p\n"
|                "%s\n",
|                adrp_self, ptr, equal ? "EQUAL" : "NOT EQUAL");
|
|         return 0;
| }

.... where the adrp_self() function was compiled to:

| 00000000004007e0 &lt;adrp_self&gt;:
|   4007e0:       90000000        adrp    x0, 400000 &lt;__ehdr_start&gt;
|   4007e4:       911f8000        add     x0, x0, #0x7e0
|   4007e8:       d65f03c0        ret

Before this patch, the ADRP is not recognized, and is assumed to be
steppable, resulting in corruption of the result:

| # ./adrp-self
| adrp_self   =&gt; 0x4007e0
| adrp_self() =&gt; 0x4007e0
| EQUAL
| # echo 'p /root/adrp-self:0x007e0' &gt; /sys/kernel/tracing/uprobe_events
| # echo 1 &gt; /sys/kernel/tracing/events/uprobes/enable
| # ./adrp-self
| adrp_self   =&gt; 0x4007e0
| adrp_self() =&gt; 0xffffffffff7e0
| NOT EQUAL

After this patch, the ADRP is correctly recognized and simulated:

| # ./adrp-self
| adrp_self   =&gt; 0x4007e0
| adrp_self() =&gt; 0x4007e0
| EQUAL
| #
| # echo 'p /root/adrp-self:0x007e0' &gt; /sys/kernel/tracing/uprobe_events
| # echo 1 &gt; /sys/kernel/tracing/events/uprobes/enable
| # ./adrp-self
| adrp_self   =&gt; 0x4007e0
| adrp_self() =&gt; 0x4007e0
| EQUAL

Fixes: 9842ceae9fa8 ("arm64: Add uprobe support")
Cc: stable@vger.kernel.org
Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20241008155851.801546-4-mark.rutland@arm.com
Signed-off-by: Will Deacon &lt;will@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>KVM: arm64: nv: Punt stage-2 recycling to a vCPU request</title>
<updated>2024-10-08T09:40:27+00:00</updated>
<author>
<name>Oliver Upton</name>
<email>oliver.upton@linux.dev</email>
</author>
<published>2024-10-07T23:30:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c268f204f7c5784e84583c1c44d427bac09f517a'/>
<id>c268f204f7c5784e84583c1c44d427bac09f517a</id>
<content type='text'>
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 &lt;oliver.upton@linux.dev&gt;
Link: https://lore.kernel.org/r/20241007233028.2236133-4-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier &lt;maz@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
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 &lt;oliver.upton@linux.dev&gt;
Link: https://lore.kernel.org/r/20241007233028.2236133-4-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier &lt;maz@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>KVM: arm64: nv: Do not block when unmapping stage-2 if disallowed</title>
<updated>2024-10-08T09:40:27+00:00</updated>
<author>
<name>Oliver Upton</name>
<email>oliver.upton@linux.dev</email>
</author>
<published>2024-10-07T23:30:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=3c164eb9464d39ba339c1487dcac0dc9508e03f0'/>
<id>3c164eb9464d39ba339c1487dcac0dc9508e03f0</id>
<content type='text'>
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 &lt;oliver.upton@linux.dev&gt;
Link: https://lore.kernel.org/r/20241007233028.2236133-3-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier &lt;maz@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
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 &lt;oliver.upton@linux.dev&gt;
Link: https://lore.kernel.org/r/20241007233028.2236133-3-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier &lt;maz@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm</title>
<updated>2024-10-06T17:53:28+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-10-06T17:53:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=4563243edeeb3dc17355a80ec16bbfdc675702cb'/>
<id>4563243edeeb3dc17355a80ec16bbfdc675702cb</id>
<content type='text'>
Pull kvm fixes from Paolo Bonzini:
 "ARM64:

   - Fix pKVM error path on init, making sure we do not change critical
     system registers as we're about to fail

   - Make sure that the host's vector length is at capped by a value
     common to all CPUs

   - Fix kvm_has_feat*() handling of "negative" features, as the current
     code is pretty broken

   - Promote Joey to the status of official reviewer, while James steps
     down -- hopefully only temporarly

  x86:

   - Fix compilation with KVM_INTEL=KVM_AMD=n

   - Fix disabling KVM_X86_QUIRK_SLOT_ZAP_ALL when shadow MMU is in use

  Selftests:

   - Fix compilation on non-x86 architectures"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  x86/reboot: emergency callbacks are now registered by common KVM code
  KVM: x86: leave kvm.ko out of the build if no vendor module is requested
  KVM: x86/mmu: fix KVM_X86_QUIRK_SLOT_ZAP_ALL for shadow MMU
  KVM: arm64: Fix kvm_has_feat*() handling of negative features
  KVM: selftests: Fix build on architectures other than x86_64
  KVM: arm64: Another reviewer reshuffle
  KVM: arm64: Constrain the host to the maximum shared SVE VL with pKVM
  KVM: arm64: Fix __pkvm_init_vcpu cptr_el2 error path
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull kvm fixes from Paolo Bonzini:
 "ARM64:

   - Fix pKVM error path on init, making sure we do not change critical
     system registers as we're about to fail

   - Make sure that the host's vector length is at capped by a value
     common to all CPUs

   - Fix kvm_has_feat*() handling of "negative" features, as the current
     code is pretty broken

   - Promote Joey to the status of official reviewer, while James steps
     down -- hopefully only temporarly

  x86:

   - Fix compilation with KVM_INTEL=KVM_AMD=n

   - Fix disabling KVM_X86_QUIRK_SLOT_ZAP_ALL when shadow MMU is in use

  Selftests:

   - Fix compilation on non-x86 architectures"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  x86/reboot: emergency callbacks are now registered by common KVM code
  KVM: x86: leave kvm.ko out of the build if no vendor module is requested
  KVM: x86/mmu: fix KVM_X86_QUIRK_SLOT_ZAP_ALL for shadow MMU
  KVM: arm64: Fix kvm_has_feat*() handling of negative features
  KVM: selftests: Fix build on architectures other than x86_64
  KVM: arm64: Another reviewer reshuffle
  KVM: arm64: Constrain the host to the maximum shared SVE VL with pKVM
  KVM: arm64: Fix __pkvm_init_vcpu cptr_el2 error path
</pre>
</div>
</content>
</entry>
</feed>
