mm, treewide: introduce NR_PAGE_ORDERS

[ Upstream commit fd37721803c6e73619108f76ad2e12a9aa5fafaf ]

NR_PAGE_ORDERS defines the number of page orders supported by the page
allocator, ranging from 0

mm, treewide: introduce NR_PAGE_ORDERS

[ Upstream commit fd37721803c6e73619108f76ad2e12a9aa5fafaf ]

NR_PAGE_ORDERS defines the number of page orders supported by the page
allocator, ranging from 0 to MAX_ORDER, MAX_ORDER + 1 in total.

NR_PAGE_ORDERS assists in defining arrays of page orders and allows for
more natural iteration over them.

[kirill.shutemov@linux.intel.com: fixup for kerneldoc warning]
Link: https://lkml.kernel.org/r/20240101111512.7empzyifq7kxtzk3@box
Link: https://lkml.kernel.org/r/20231228144704.14033-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: b6976f323a86 ("drm/ttm: stop pooling cached NUMA pages v2")
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

mm, treewide: introduce NR_PAGE_ORDERS

[ Upstream commit fd37721803c6e73619108f76ad2e12a9aa5fafaf ]

NR_PAGE_ORDERS defines the number of page orders supported by the page
allocator, ranging from 0

mm, treewide: introduce NR_PAGE_ORDERS

[ Upstream commit fd37721803c6e73619108f76ad2e12a9aa5fafaf ]

NR_PAGE_ORDERS defines the number of page orders supported by the page
allocator, ranging from 0 to MAX_ORDER, MAX_ORDER + 1 in total.

NR_PAGE_ORDERS assists in defining arrays of page orders and allows for
more natural iteration over them.

[kirill.shutemov@linux.intel.com: fixup for kerneldoc warning]
Link: https://lkml.kernel.org/r/20240101111512.7empzyifq7kxtzk3@box
Link: https://lkml.kernel.org/r/20231228144704.14033-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: b6976f323a86 ("drm/ttm: stop pooling cached NUMA pages v2")
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

mm, treewide: introduce NR_PAGE_ORDERS

[ Upstream commit fd37721803c6e73619108f76ad2e12a9aa5fafaf ]

NR_PAGE_ORDERS defines the number of page orders supported by the page
allocator, ranging from 0

mm, treewide: introduce NR_PAGE_ORDERS

[ Upstream commit fd37721803c6e73619108f76ad2e12a9aa5fafaf ]

NR_PAGE_ORDERS defines the number of page orders supported by the page
allocator, ranging from 0 to MAX_ORDER, MAX_ORDER + 1 in total.

NR_PAGE_ORDERS assists in defining arrays of page orders and allows for
more natural iteration over them.

[kirill.shutemov@linux.intel.com: fixup for kerneldoc warning]
Link: https://lkml.kernel.org/r/20240101111512.7empzyifq7kxtzk3@box
Link: https://lkml.kernel.org/r/20231228144704.14033-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: b6976f323a86 ("drm/ttm: stop pooling cached NUMA pages v2")
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

mm, treewide: redefine MAX_ORDER sanely

MAX_ORDER currently defined as number of orders page allocator supports:
user can ask buddy allocator for page order between 0 and MAX_ORDER-1.

This definiti

mm, treewide: redefine MAX_ORDER sanely

MAX_ORDER currently defined as number of orders page allocator supports:
user can ask buddy allocator for page order between 0 and MAX_ORDER-1.

This definition is counter-intuitive and lead to number of bugs all over
the kernel.

Change the definition of MAX_ORDER to be inclusive: the range of orders
user can ask from buddy allocator is 0..MAX_ORDER now.

[kirill@shutemov.name: fix min() warning]
Link: https://lkml.kernel.org/r/20230315153800.32wib3n5rickolvh@box
[akpm@linux-foundation.org: fix another min_t warning]
[kirill@shutemov.name: fixups per Zi Yan]
Link: https://lkml.kernel.org/r/20230316232144.b7ic4cif4kjiabws@box.shutemov.name
[akpm@linux-foundation.org: fix underlining in docs]
Link: https://lore.kernel.org/oe-kbuild-all/202303191025.VRCTk6mP-lkp@intel.com/
Link: https://lkml.kernel.org/r/20230315113133.11326-11-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc]
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

KVM: arm64: Fix host stage-2 PGD refcount

The KVM page-table library refcounts the pages of concatenated stage-2
PGDs individually. However, when running KVM in protected mode, the
host's stage-2 PG

KVM: arm64: Fix host stage-2 PGD refcount

The KVM page-table library refcounts the pages of concatenated stage-2
PGDs individually. However, when running KVM in protected mode, the
host's stage-2 PGD is currently managed by EL2 as a single high-order
compound page, which can cause the refcount of the tail pages to reach 0
when they shouldn't, hence corrupting the page-table.

Fix this by introducing a new hyp_split_page() helper in the EL2 page
allocator (matching the kernel's split_page() function), and make use of
it from host_s2_zalloc_pages_exact().

Fixes: 1025c8c0c6ac ("KVM: arm64: Wrap the host with a stage 2")
Acked-by: Will Deacon <will@kernel.org>
Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211005090155.734578-5-qperret@google.com

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KVM: arm64: Use less bits for hyp_page order

The hyp_page order is currently encoded on 4 bytes even though it is
guaranteed to be smaller than this. Make it 2 bytes to reduce the hyp
vmemmap overhe

KVM: arm64: Use less bits for hyp_page order

The hyp_page order is currently encoded on 4 bytes even though it is
guaranteed to be smaller than this. Make it 2 bytes to reduce the hyp
vmemmap overhead.

Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210608114518.748712-7-qperret@google.com

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KVM: arm64: Remove hyp_pool pointer from struct hyp_page

Each struct hyp_page currently contains a pointer to a hyp_pool struct
where the page should be freed if its refcount reaches 0. However, thi

KVM: arm64: Remove hyp_pool pointer from struct hyp_page

Each struct hyp_page currently contains a pointer to a hyp_pool struct
where the page should be freed if its refcount reaches 0. However, this
information can always be inferred from the context in the EL2 code, so
drop the pointer to save a few bytes in the vmemmap.

Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210608114518.748712-6-qperret@google.com

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KVM: arm64: Move hyp_pool locking out of refcount helpers

The hyp_page refcount helpers currently rely on the hyp_pool lock for
serialization. However, this means the refcounts can't be changed from

KVM: arm64: Move hyp_pool locking out of refcount helpers

The hyp_page refcount helpers currently rely on the hyp_pool lock for
serialization. However, this means the refcounts can't be changed from
the buddy allocator core as it already holds the lock, which means pages
have to go through odd transient states.

For example, when a page is freed, its refcount is set to 0, and the
lock is transiently released before the page can be attached to a free
list in the buddy tree. This is currently harmless as the allocator
checks the list node of each page to see if it is available for
allocation or not, but it means the page refcount can't be trusted to
represent the state of the page even if the pool lock is held.

In order to fix this, remove the pool locking from the refcount helpers,
and move all the logic to the buddy allocator. This will simplify the
removal of the list node from struct hyp_page in a later patch.

Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210608114518.748712-2-qperret@google.com

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KVM: arm64: Introduce a Hyp buddy page allocator

When memory protection is enabled, the hyp code will require a basic
form of memory management in order to allocate and free memory pages at
EL2. Thi

KVM: arm64: Introduce a Hyp buddy page allocator

When memory protection is enabled, the hyp code will require a basic
form of memory management in order to allocate and free memory pages at
EL2. This is needed for various use-cases, including the creation of hyp
mappings or the allocation of stage 2 page tables.

To address these use-case, introduce a simple memory allocator in the
hyp code. The allocator is designed as a conventional 'buddy allocator',
working with a page granularity. It allows to allocate and free
physically contiguous pages from memory 'pools', with a guaranteed order
alignment in the PA space. Each page in a memory pool is associated
with a struct hyp_page which holds the page's metadata, including its
refcount, as well as its current order, hence mimicking the kernel's
buddy system in the GFP infrastructure. The hyp_page metadata are made
accessible through a hyp_vmemmap, following the concept of
SPARSE_VMEMMAP in the kernel.

Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210319100146.1149909-13-qperret@google.com

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