[ Upstream commit 0949c646d6 ]
This partially reverts commit 87af633689 so
the current memory target for PV guests is still fetched from
start_info->nr_pages, which matches exactly what the toolstack sets the
initial memory target to.
Using get_num_physpages() is possible on PV also, but needs adjusting to
take into account the ISA hole and the PFN at 0 not considered usable
memory despite being populated, and hence would need extra adjustments.
Instead of carrying those extra adjustments switch back to the previous
code. That leaves Linux with a difference in how current memory target is
obtained for HVM vs PV, but that's better than adding extra logic just for
PV.
However if switching to start_info->nr_pages for PV domains we need to
differentiate between released pages (freed back to the hypervisor) as
opposed to pages in the physmap which are not populated to start with.
Introduce a new xen_unpopulated_pages to account for papges that have
never been populated, and hence in the PV case don't need subtracting.
Fixes: 87af633689 ("x86/xen: fix balloon target initialization for PVH dom0")
Reported-by: James Dingwall <james@dingwall.me.uk>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Message-ID: <20260128110510.46425-2-roger.pau@citrix.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit e5aff444e3 ]
The sparse tool issues a warning for arch/x76/xen/enlighten_pv.c:
arch/x86/xen/enlighten_pv.c:120:9: sparse: sparse: incorrect type
in initializer (different address spaces)
expected void const [noderef] __percpu *__vpp_verify
got bool *
This is due to the percpu variable xen_in_preemptible_hcall being
exported via EXPORT_SYMBOL_GPL() instead of EXPORT_PER_CPU_SYMBOL_GPL().
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202512140856.Ic6FetG6-lkp@intel.com/
Fixes: fdfd811ddd ("x86/xen: allow privcmd hypercalls to be preempted")
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Message-ID: <20251215115112.15072-1-jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 64a66e2c3b ]
When running as a PVH dom0 the ACPI tables exposed to Linux are (mostly)
the native ones, thus exposing the C and P states, that can lead to
attachment of CPU idle and frequency drivers. However the entity in
control of the CPU C and P states is Xen, as dom0 doesn't have a full view
of the system load, neither has all CPUs assigned and identity pinned.
Like it's done for classic PV guests, prevent Linux from using idle or
frequency state drivers when running as a PVH dom0.
On an AMD EPYC 7543P system without this fix a Linux PVH dom0 will keep the
host CPUs spinning at 100% even when dom0 is completely idle, as it's
attempting to use the acpi_idle driver.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jason Andryuk <jason.andryuk@amd.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Message-ID: <20250407101842.67228-1-roger.pau@citrix.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 715ad3e0ec ]
Initializing a percpu variable with the address of a struct tagged as
.initdata is breaking the build with CONFIG_SECTION_MISMATCH_WARN_ONLY
not set to "y".
Fix that by using an access function instead returning the .initdata
struct address if the percpu space of the struct hasn't been
allocated yet.
Fixes: 368990a7fe ("xen: fix multicall debug data referencing")
Reported-by: Borislav Petkov <bp@alien8.de>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: "Borislav Petkov (AMD)" <bp@alien8.de>
Tested-by: "Borislav Petkov (AMD)" <bp@alien8.de>
Signed-off-by: Juergen Gross <jgross@suse.com>
Message-ID: <20250327190602.26015-1-jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 87af633689 upstream.
PVH dom0 re-uses logic from PV dom0, in which RAM ranges not assigned to
dom0 are re-used as scratch memory to map foreign and grant pages. Such
logic relies on reporting those unpopulated ranges as RAM to Linux, and
mark them as reserved. This way Linux creates the underlying page
structures required for metadata management.
Such approach works fine on PV because the initial balloon target is
calculated using specific Xen data, that doesn't take into account the
memory type changes described above. However on HVM and PVH the initial
balloon target is calculated using get_num_physpages(), and that function
does take into account the unpopulated RAM regions used as scratch space
for remote domain mappings.
This leads to PVH dom0 having an incorrect initial balloon target, which
causes malfunction (excessive memory freeing) of the balloon driver if the
dom0 memory target is later adjusted from the toolstack.
Fix this by using xen_released_pages to account for any pages that are part
of the memory map, but are already unpopulated when the balloon driver is
initialized. This accounts for any regions used for scratch remote
mappings. Note on x86 xen_released_pages definition is moved to
enlighten.c so it's uniformly available for all Xen-enabled builds.
Take the opportunity to unify PV with PVH/HVM guests regarding the usage of
get_num_physpages(), as that avoids having to add different logic for PV vs
PVH in both balloon_add_regions() and arch_xen_unpopulated_init().
Much like a6aa4eb994, the code in this changeset should have been part of
38620fc4e8.
Fixes: a6aa4eb994 ('xen/x86: add extra pages to unpopulated-alloc if available')
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: stable@vger.kernel.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Message-ID: <20250407082838.65495-1-roger.pau@citrix.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit e93ec87286 ]
Today a PV guest (including dom0) can create 2MB contiguous memory
regions for DMA buffers at max. This has led to problems at least
with the megaraid_sas driver, which wants to allocate a 2.3MB DMA
buffer.
The limiting factor is the frame array used to do the hypercall for
making the memory contiguous, which has 512 entries and is just a
static array in mmu_pv.c.
In order to not waste memory for non-PV guests, put the initial
frame array into .init.data section and dynamically allocate an array
from the .init_after_bootmem hook of PV guests.
In case a contiguous memory area larger than the initially supported
2MB is requested, allocate a larger buffer for the frame list. Note
that such an allocation is tried only after memory management has been
initialized properly, which is tested via a flag being set in the
.init_after_bootmem hook.
Fixes: 9f40ec84a7 ("xen/swiotlb: add alignment check for dma buffers")
Signed-off-by: Juergen Gross <jgross@suse.com>
Tested-by: Alan Robinson <Alan.Robinson@fujitsu.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 98a5cfd232 ]
xen_hypercall_hvm(), which is used when running as a Xen PVH guest at
most only once during early boot, is clobbering %rbx. Depending on
whether the caller relies on %rbx to be preserved across the call or
not, this clobbering might result in an early crash of the system.
This can be avoided by using an already saved register instead of %rbx.
Fixes: b4845bb638 ("x86/xen: add central hypercall functions")
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 7fa0da5373 upstream.
The hypercall page is no longer needed. It can be removed, as from the
Xen perspective it is optional.
But, from Linux's perspective, it removes naked RET instructions that
escape the speculative protections that Call Depth Tracking and/or
Untrain Ret are trying to achieve.
This is part of XSA-466 / CVE-2024-53241.
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b4845bb638 upstream.
Add generic hypercall functions usable for all normal (i.e. not iret)
hypercalls. Depending on the guest type and the processor vendor
different functions need to be used due to the to be used instruction
for entering the hypervisor:
- PV guests need to use syscall
- HVM/PVH guests on Intel need to use vmcall
- HVM/PVH guests on AMD and Hygon need to use vmmcall
As PVH guests need to issue hypercalls very early during boot, there
is a 4th hypercall function needed for HVM/PVH which can be used on
Intel and AMD processors. It will check the vendor type and then set
the Intel or AMD specific function to use via static_call().
This is part of XSA-466 / CVE-2024-53241.
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Co-developed-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a2796dff62 upstream.
Instead of jumping to the Xen hypercall page for doing the iret
hypercall, directly code the required sequence in xen-asm.S.
This is done in preparation of no longer using hypercall page at all,
as it has shown to cause problems with speculation mitigations.
This is part of XSA-466 / CVE-2024-53241.
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Recent topology checks of the x86 boot code uncovered the need for
PV guests to have the boot cpu marked in the APICBASE MSR.
Fixes: 9d22c96316 ("x86/topology: Handle bogus ACPI tables correctly")
Reported-by: Niels Dettenbach <nd@syndicat.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Juergen Gross <jgross@suse.com>
Pull more xen updates from Juergen Gross:
"A second round of Xen related changes and features:
- a small fix of the xen-pciback driver for a warning issued by
sparse
- support PCI passthrough when using a PVH dom0
- enable loading the kernel in PVH mode at arbitrary addresses,
avoiding conflicts with the memory map when running as a Xen dom0
using the host memory layout"
* tag 'for-linus-6.12-rc1a-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
x86/pvh: Add 64bit relocation page tables
x86/kernel: Move page table macros to header
x86/pvh: Set phys_base when calling xen_prepare_pvh()
x86/pvh: Make PVH entrypoint PIC for x86-64
xen: sync elfnote.h from xen tree
xen/pciback: fix cast to restricted pci_ers_result_t and pci_power_t
xen/privcmd: Add new syscall to get gsi from dev
xen/pvh: Setup gsi for passthrough device
xen/pci: Add a function to reset device for xen
In PVH dom0, the gsis don't get registered, but the gsi of
a passthrough device must be configured for it to be able to be
mapped into a domU.
When assigning a device to passthrough, proactively setup the gsi
of the device during that process.
Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Message-ID: <20240924061437.2636766-3-Jiqian.Chen@amd.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
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
...
In order to minimize required special handling for running as Xen PV
dom0, the memory layout is modified to match that of the host. This
requires to have only RAM at the locations where Xen allocated memory
is living. Unfortunately there seem to be some machines, where ACPI
NVS is located at 64 MB, resulting in a conflict with the loaded
kernel or the initial page tables built by Xen.
Avoid this conflict by swapping the ACPI NVS area in the memory map
with unused RAM. This is possible via modification of the dom0 P2M map.
Accesses to the ACPI NVS area are done either for saving and restoring
it across suspend operations (this will work the same way as before),
or by ACPI code when NVS memory is referenced from other ACPI tables.
The latter case is handled by a Xen specific indirection of
acpi_os_ioremap().
While the E820 map can (and should) be modified right away, the P2M
map can be updated only after memory allocation is working, as the P2M
map might need to be extended.
Fixes: 808fdb7193 ("xen: check for kernel memory conflicting with memory layout")
Signed-off-by: Juergen Gross <jgross@suse.com>
Tested-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
When running as a Xen PV dom0 the system needs to map ACPI data of the
host using host physical addresses, while those addresses can conflict
with the guest physical addresses of the loaded linux kernel. The same
problem might apply in case a PV guest is configured to use the host
memory map.
This conflict can be solved by mapping the ACPI data to a different
guest physical address, but mapping the data via acpi_os_ioremap()
must still be possible using the host physical address, as this
address might be generated by AML when referencing some of the ACPI
data.
When configured to support running as a Xen PV domain, have an
implementation of acpi_os_ioremap() being aware of the possibility to
need above mentioned translation of a host physical address to the
guest physical address.
This modification requires to #include linux/acpi.h in some sources
which need to include asm/acpi.h directly.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
When running as a Xen PV dom0 it can happen that the kernel is being
loaded to a guest physical address conflicting with the host memory
map.
In order to be able to resolve this conflict, add the capability to
remap non-RAM areas to different guest PFNs. A function to use this
remapping information for other purposes than doing the remap will be
added when needed.
As the number of conflicts should be rather low (currently only
machines with max. 1 conflict are known), save the remap data in a
small statically allocated array.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Instead of having max_pfn as a local variable of xen_memory_setup(),
make it a static variable in setup.c instead. This avoids having to
pass it to subfunctions, which will be needed in more cases in future.
Rename it to ini_nr_pages, as the value denotes the currently usable
number of memory pages as passed from the hypervisor at boot time.
Signed-off-by: Juergen Gross <jgross@suse.com>
Tested-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Move the checks for e820 memory map conflicts using the
xen_chk_is_e820_usable() helper further up in order to prepare
resolving some of the possible conflicts by doing some e820 map
modifications, which must happen before evaluating the RAM layout.
Signed-off-by: Juergen Gross <jgross@suse.com>
Tested-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
When booting as a Xen PV dom0 the memory layout of the dom0 is
modified to match that of the host, as this requires less changes in
the kernel for supporting Xen.
There are some cases, though, which are problematic, as it is the Xen
hypervisor selecting the kernel's load address plus some other data,
which might conflict with the host's memory map.
These conflicts are detected at boot time and result in a boot error.
In order to support handling at least some of these conflicts in
future, introduce a generic helper function which will later gain the
ability to adapt the memory layout when possible.
Add the missing check for the xen_start_info area.
Note that possible p2m map and initrd memory conflicts are handled
already by copying the data to memory areas not conflicting with the
memory map. The initial stack allocated by Xen doesn't need to be
checked, as early boot code is switching to the statically allocated
initial kernel stack. Initial page tables and the kernel itself will
be handled later.
Signed-off-by: Juergen Gross <jgross@suse.com>
Tested-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
When running as a Xen PV dom0 the kernel is loaded by the hypervisor
using a different memory map than that of the host. In order to
minimize the required changes in the kernel, the kernel adapts its
memory map to that of the host. In order to do that it is checking
for conflicts of its load address with the host memory map.
Unfortunately the tested memory range does not include the .brk
area, which might result in crashes or memory corruption when this
area does conflict with the memory map of the host.
Fix the test by using the _end label instead of __bss_stop.
Fixes: 808fdb7193 ("xen: check for kernel memory conflicting with memory layout")
Signed-off-by: Juergen Gross <jgross@suse.com>
Tested-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Pull xen fixes from Juergen Gross:
"Two fixes for issues introduced in this merge window:
- fix enhanced debugging in the Xen multicall handling
- two patches fixing a boot failure when running as dom0 in PVH mode"
* tag 'for-linus-6.11-rc1a-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
x86/xen: fix memblock_reserve() usage on PVH
x86/xen: move xen_reserve_extra_memory()
xen: fix multicall debug data referencing
We have some very fancy min/max macros that have tons of sanity checking
to warn about mixed signedness etc.
This is all things that a sane compiler should warn about, but there are
no sane compiler interfaces for this, and '-Wsign-compare' is broken [1]
and not useful.
So then we compensate (some would say over-compensate) by doing the
checks manually with some truly horrid macro games.
And no, we can't just use __builtin_types_compatible_p(), because the
whole question of "does it make sense to compare these two values" is a
lot more complicated than that.
For example, it makes a ton of sense to compare unsigned values with
simple constants like "5", even if that is indeed a signed type. So we
have these very strange macros to try to make sensible type checking
decisions on the arguments to 'min()' and 'max()'.
But that can cause enormous code expansion if the min()/max() macros are
used with complicated expressions, and particularly if you nest these
things so that you get the first big expansion then expanded again.
The xen setup.c file ended up ballooning to over 50MB of preprocessed
noise that takes 15s to compile (obviously depending on the build host),
largely due to one single line.
So let's split that one single line to just be simpler. I think it ends
up being more legible to humans too at the same time. Now that single
file compiles in under a second.
Reported-and-reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Link: https://lore.kernel.org/all/c83c17bb-be75-4c67-979d-54eee38774c6@lucifer.local/
Link: https://staticthinking.wordpress.com/2023/07/25/wsign-compare-is-garbage/ [1]
Cc: David Laight <David.Laight@aculab.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The current usage of memblock_reserve() in init_pvh_bootparams() is done before
the .bss is zeroed, and that used to be fine when
memblock_reserved_init_regions implicitly ended up in the .meminit.data
section. However after commit 73db3abdca memblock_reserved_init_regions
ends up in the .bss section, thus breaking it's usage before the .bss is
cleared.
Move and rename the call to xen_reserve_extra_memory() so it's done in the
x86_init.oem.arch_setup hook, which gets executed after the .bss has been
zeroed, but before calling e820__memory_setup().
Fixes: 73db3abdca ("init/modpost: conditionally check section mismatch to __meminit*")
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Message-ID: <20240725073116.14626-3-roger.pau@citrix.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
The xen_nopvspin boot parameter is deprecated since 2019. nopvspin
can be used instead.
Remove the xen_nopvspin boot parameter and replace the xen_pvspin
variable use cases with nopvspin.
This requires to move the nopvspin variable out of the .initdata
section, as it needs to be accessed for cpuhotplug, too.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Message-ID: <20240710110139.22300-1-jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Under arch/x86/xen there is one large private header file xen-ops.h
containing most of the Xen-private x86 related declarations, and then
there are several small headers with a handful of declarations each.
Merge the small headers into xen-ops.h.
While doing that, move the declaration of xen_fifo_events from
xen-ops.h into include/xen/events.h where it should have been from the
beginning.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Message-ID: <20240710093718.14552-3-jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Today Xen multicall debugging needs to be enabled via modifying a
define in a source file for getting debug data of multicall errors
encountered by users.
Switch multicall debugging to depend on a boot parameter "xen_mc_debug"
instead, enabling affected users to boot with the new parameter set in
order to get better diagnostics.
With debugging enabled print the following information in case at least
one of the batched calls failed:
- all calls of the batch with operation, result and caller
- all parameters of each call
- all parameters stored in the multicall data for each call
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Message-ID: <20240710092749.13595-1-jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Current timer tick is causing some deadline to fail.
The current high value constant was probably due to an old
bug in the Xen timer implementation causing errors if the
deadline was in the future.
This was fixed in Xen commit:
19c6cbd90965 xen/vcpu: ignore VCPU_SSHOTTMR_future
Usage of VCPU_SSHOTTMR_future in Linux kernel was removed by:
c06b6d70fe xen/x86: don't lose event interrupts
Signed-off-by: Frediano Ziglio <frediano.ziglio@cloud.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20240619104015.30477-1-frediano.ziglio@cloud.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Pull xen updates from Juergen Gross:
- a small cleanup in the drivers/xen/xenbus Makefile
- a fix of the Xen xenstore driver to improve connecting to a late
started Xenstore
- an enhancement for better support of ballooning in PVH guests
- a cleanup using try_cmpxchg() instead of open coding it
* tag 'for-linus-6.10a-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
drivers/xen: Improve the late XenStore init protocol
xen/xenbus: Use *-y instead of *-objs in Makefile
xen/x86: add extra pages to unpopulated-alloc if available
locking/x86/xen: Use try_cmpxchg() in xen_alloc_p2m_entry()
Commit 262fc47ac1 ('xen/balloon: don't use PV mode extra memory for zone
device allocations') removed the addition of the extra memory ranges to the
unpopulated range allocator, using those only for the balloon driver.
This forces the unpopulated allocator to attach hotplug ranges even when spare
memory (as part of the extra memory ranges) is available. Furthermore, on PVH
domains it defeats the purpose of commit 38620fc4e8 ('x86/xen: attempt to
inflate the memory balloon on PVH'), as extra memory ranges would only be
used to map foreign memory if the kernel is built without XEN_UNPOPULATED_ALLOC
support.
Fix this by adding a helpers that adds the extra memory ranges to the list of
unpopulated pages, and zeroes the ranges so they are not also consumed by the
balloon driver.
This should have been part of 38620fc4e8, hence the fixes tag.
Note the current logic relies on unpopulated_init() (and hence
arch_xen_unpopulated_init()) always being called ahead of balloon_init(), so
that the extra memory regions are consumed by arch_xen_unpopulated_init().
Fixes: 38620fc4e8 ('x86/xen: attempt to inflate the memory balloon on PVH')
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20240429155053.72509-1-roger.pau@citrix.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Pull x86 cleanups from Ingo Molnar:
- Fix function prototypes to address clang function type cast
warnings in the math-emu code
- Reorder definitions in <asm/msr-index.h>
- Remove unused code
- Fix typos
- Simplify #include sections
* tag 'x86-cleanups-2024-05-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/pci/ce4100: Remove unused 'struct sim_reg_op'
x86/msr: Move ARCH_CAP_XAPIC_DISABLE bit definition to its rightful place
x86/math-emu: Fix function cast warnings
x86/extable: Remove unused fixup type EX_TYPE_COPY
x86/rtc: Remove unused intel-mid.h
x86/32: Remove unused IA32_STACK_TOP and two externs
x86/head: Simplify relative include path to xen-head.S
x86/fred: Fix typo in Kconfig description
x86/syscall/compat: Remove ia32_unistd.h
x86/syscall/compat: Remove unused macro __SYSCALL_ia32_NR
x86/virt/tdx: Remove duplicate include
x86/xen: Remove duplicate #include
Pull x86 boot updates from Ingo Molnar:
- Move the kernel cmdline setup earlier in the boot process (again),
to address a split_lock_detect= boot parameter bug
- Ignore relocations in .notes sections
- Simplify boot stack setup
- Re-introduce a bootloader quirk wrt CR4 handling
- Miscellaneous cleanups & fixes
* tag 'x86-boot-2024-05-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/boot/64: Clear most of CR4 in startup_64(), except PAE, MCE and LA57
x86/boot: Move kernel cmdline setup earlier in the boot process (again)
x86/build: Clean up arch/x86/tools/relocs.c a bit
x86/boot: Ignore relocations in .notes sections in walk_relocs() too
x86: Rename __{start,end}_init_task to __{start,end}_init_stack
x86/boot: Simplify boot stack setup
With recent sanity checks for topology information added, there are now
warnings issued for APs when running as a Xen PV guest:
[Firmware Bug]: CPU 1: APIC ID mismatch. CPUID: 0x0000 APIC: 0x0001
This is due to the initial APIC ID obtained via CPUID for PV guests is
always 0.
Avoid the warnings by synthesizing the CPUID data to contain the same
initial APIC ID as xen_pv_smp_config() is using for registering the
APIC IDs of all CPUs.
Fixes: 52128a7a21 ("86/cpu/topology: Make the APIC mismatch warnings complete")
Signed-off-by: Juergen Gross <jgross@suse.com>
The topology core expects the boot APIC to be registered from earhy APIC
detection first and then again when the firmware tables are evaluated. This
is used for detecting the real BSP CPU on a kexec kernel.
The recent conversion of XEN/PV to register fake APIC IDs failed to
register the boot CPU APIC correctly as it only registers it once. This
causes the BSP detection mechanism to trigger wrongly:
CPU topo: Boot CPU APIC ID not the first enumerated APIC ID: 0 > 1
Additionally this results in one CPU being ignored.
Register the boot CPU APIC twice so that the XEN/PV fake enumeration
behaves like real firmware.
Reported-by: Juergen Gross <jgross@suse.com>
Fixes: e753070234 ("x86/xen/smp_pv: Register fake APICs")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/87a5l8s2fg.ffs@tglx
Signed-off-by: Juergen Gross <jgross@suse.com>
Pull Kbuild updates from Masahiro Yamada:
- Generate a list of built DTB files (arch/*/boot/dts/dtbs-list)
- Use more threads when building Debian packages in parallel
- Fix warnings shown during the RPM kernel package uninstallation
- Change OBJECT_FILES_NON_STANDARD_*.o etc. to take a relative path to
Makefile
- Support GCC's -fmin-function-alignment flag
- Fix a null pointer dereference bug in modpost
- Add the DTB support to the RPM package
- Various fixes and cleanups in Kconfig
* tag 'kbuild-v6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (67 commits)
kconfig: tests: test dependency after shuffling choices
kconfig: tests: add a test for randconfig with dependent choices
kconfig: tests: support KCONFIG_SEED for the randconfig runner
kbuild: rpm-pkg: add dtb files in kernel rpm
kconfig: remove unneeded menu_is_visible() call in conf_write_defconfig()
kconfig: check prompt for choice while parsing
kconfig: lxdialog: remove unused dialog colors
kconfig: lxdialog: fix button color for blackbg theme
modpost: fix null pointer dereference
kbuild: remove GCC's default -Wpacked-bitfield-compat flag
kbuild: unexport abs_srctree and abs_objtree
kbuild: Move -Wenum-{compare-conditional,enum-conversion} into W=1
kconfig: remove named choice support
kconfig: use linked list in get_symbol_str() to iterate over menus
kconfig: link menus to a symbol
kbuild: fix inconsistent indentation in top Makefile
kbuild: Use -fmin-function-alignment when available
alpha: merge two entries for CONFIG_ALPHA_GAMMA
alpha: merge two entries for CONFIG_ALPHA_EV4
kbuild: change DTC_FLAGS_<basetarget>.o to take the path relative to $(obj)
...
Pull xen updates from Juergen Gross:
- Xen event channel handling fix for a regression with a rare kernel
config and some added hardening
- better support of running Xen dom0 in PVH mode
- a cleanup for the xen grant-dma-iommu driver
* tag 'for-linus-6.9-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen/events: increment refcnt only if event channel is refcounted
xen/evtchn: avoid WARN() when unbinding an event channel
x86/xen: attempt to inflate the memory balloon on PVH
xen/grant-dma-iommu: Convert to platform remove callback returning void
Pull MM updates from Andrew Morton:
- Sumanth Korikkar has taught s390 to allocate hotplug-time page frames
from hotplugged memory rather than only from main memory. Series
"implement "memmap on memory" feature on s390".
- More folio conversions from Matthew Wilcox in the series
"Convert memcontrol charge moving to use folios"
"mm: convert mm counter to take a folio"
- Chengming Zhou has optimized zswap's rbtree locking, providing
significant reductions in system time and modest but measurable
reductions in overall runtimes. The series is "mm/zswap: optimize the
scalability of zswap rb-tree".
- Chengming Zhou has also provided the series "mm/zswap: optimize zswap
lru list" which provides measurable runtime benefits in some
swap-intensive situations.
- And Chengming Zhou further optimizes zswap in the series "mm/zswap:
optimize for dynamic zswap_pools". Measured improvements are modest.
- zswap cleanups and simplifications from Yosry Ahmed in the series
"mm: zswap: simplify zswap_swapoff()".
- In the series "Add DAX ABI for memmap_on_memory", Vishal Verma has
contributed several DAX cleanups as well as adding a sysfs tunable to
control the memmap_on_memory setting when the dax device is
hotplugged as system memory.
- Johannes Weiner has added the large series "mm: zswap: cleanups",
which does that.
- More DAMON work from SeongJae Park in the series
"mm/damon: make DAMON debugfs interface deprecation unignorable"
"selftests/damon: add more tests for core functionalities and corner cases"
"Docs/mm/damon: misc readability improvements"
"mm/damon: let DAMOS feeds and tame/auto-tune itself"
- In the series "mm/mempolicy: weighted interleave mempolicy and sysfs
extension" Rakie Kim has developed a new mempolicy interleaving
policy wherein we allocate memory across nodes in a weighted fashion
rather than uniformly. This is beneficial in heterogeneous memory
environments appearing with CXL.
- Christophe Leroy has contributed some cleanup and consolidation work
against the ARM pagetable dumping code in the series "mm: ptdump:
Refactor CONFIG_DEBUG_WX and check_wx_pages debugfs attribute".
- Luis Chamberlain has added some additional xarray selftesting in the
series "test_xarray: advanced API multi-index tests".
- Muhammad Usama Anjum has reworked the selftest code to make its
human-readable output conform to the TAP ("Test Anything Protocol")
format. Amongst other things, this opens up the use of third-party
tools to parse and process out selftesting results.
- Ryan Roberts has added fork()-time PTE batching of THP ptes in the
series "mm/memory: optimize fork() with PTE-mapped THP". Mainly
targeted at arm64, this significantly speeds up fork() when the
process has a large number of pte-mapped folios.
- David Hildenbrand also gets in on the THP pte batching game in his
series "mm/memory: optimize unmap/zap with PTE-mapped THP". It
implements batching during munmap() and other pte teardown
situations. The microbenchmark improvements are nice.
- And in the series "Transparent Contiguous PTEs for User Mappings"
Ryan Roberts further utilizes arm's pte's contiguous bit ("contpte
mappings"). Kernel build times on arm64 improved nicely. Ryan's
series "Address some contpte nits" provides some followup work.
- In the series "mm/hugetlb: Restore the reservation" Breno Leitao has
fixed an obscure hugetlb race which was causing unnecessary page
faults. He has also added a reproducer under the selftest code.
- In the series "selftests/mm: Output cleanups for the compaction
test", Mark Brown did what the title claims.
- Kinsey Ho has added the series "mm/mglru: code cleanup and
refactoring".
- Even more zswap material from Nhat Pham. The series "fix and extend
zswap kselftests" does as claimed.
- In the series "Introduce cpu_dcache_is_aliasing() to fix DAX
regression" Mathieu Desnoyers has cleaned up and fixed rather a mess
in our handling of DAX on archiecctures which have virtually aliasing
data caches. The arm architecture is the main beneficiary.
- Lokesh Gidra's series "per-vma locks in userfaultfd" provides
dramatic improvements in worst-case mmap_lock hold times during
certain userfaultfd operations.
- Some page_owner enhancements and maintenance work from Oscar Salvador
in his series
"page_owner: print stacks and their outstanding allocations"
"page_owner: Fixup and cleanup"
- Uladzislau Rezki has contributed some vmalloc scalability
improvements in his series "Mitigate a vmap lock contention". It
realizes a 12x improvement for a certain microbenchmark.
- Some kexec/crash cleanup work from Baoquan He in the series "Split
crash out from kexec and clean up related config items".
- Some zsmalloc maintenance work from Chengming Zhou in the series
"mm/zsmalloc: fix and optimize objects/page migration"
"mm/zsmalloc: some cleanup for get/set_zspage_mapping()"
- Zi Yan has taught the MM to perform compaction on folios larger than
order=0. This a step along the path to implementaton of the merging
of large anonymous folios. The series is named "Enable >0 order folio
memory compaction".
- Christoph Hellwig has done quite a lot of cleanup work in the
pagecache writeback code in his series "convert write_cache_pages()
to an iterator".
- Some modest hugetlb cleanups and speedups in Vishal Moola's series
"Handle hugetlb faults under the VMA lock".
- Zi Yan has changed the page splitting code so we can split huge pages
into sizes other than order-0 to better utilize large folios. The
series is named "Split a folio to any lower order folios".
- David Hildenbrand has contributed the series "mm: remove
total_mapcount()", a cleanup.
- Matthew Wilcox has sought to improve the performance of bulk memory
freeing in his series "Rearrange batched folio freeing".
- Gang Li's series "hugetlb: parallelize hugetlb page init on boot"
provides large improvements in bootup times on large machines which
are configured to use large numbers of hugetlb pages.
- Matthew Wilcox's series "PageFlags cleanups" does that.
- Qi Zheng's series "minor fixes and supplement for ptdesc" does that
also. S390 is affected.
- Cleanups to our pagemap utility functions from Peter Xu in his series
"mm/treewide: Replace pXd_large() with pXd_leaf()".
- Nico Pache has fixed a few things with our hugepage selftests in his
series "selftests/mm: Improve Hugepage Test Handling in MM
Selftests".
- Also, of course, many singleton patches to many things. Please see
the individual changelogs for details.
* tag 'mm-stable-2024-03-13-20-04' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (435 commits)
mm/zswap: remove the memcpy if acomp is not sleepable
crypto: introduce: acomp_is_async to expose if comp drivers might sleep
memtest: use {READ,WRITE}_ONCE in memory scanning
mm: prohibit the last subpage from reusing the entire large folio
mm: recover pud_leaf() definitions in nopmd case
selftests/mm: skip the hugetlb-madvise tests on unmet hugepage requirements
selftests/mm: skip uffd hugetlb tests with insufficient hugepages
selftests/mm: dont fail testsuite due to a lack of hugepages
mm/huge_memory: skip invalid debugfs new_order input for folio split
mm/huge_memory: check new folio order when split a folio
mm, vmscan: retry kswapd's priority loop with cache_trim_mode off on failure
mm: add an explicit smp_wmb() to UFFDIO_CONTINUE
mm: fix list corruption in put_pages_list
mm: remove folio from deferred split list before uncharging it
filemap: avoid unnecessary major faults in filemap_fault()
mm,page_owner: drop unnecessary check
mm,page_owner: check for null stack_record before bumping its refcount
mm: swap: fix race between free_swap_and_cache() and swapoff()
mm/treewide: align up pXd_leaf() retval across archs
mm/treewide: drop pXd_large()
...
Roger Pau Monne
Juergen Gross
Brian Gerst
Kirill A. Shutemov
Maksym Planeta
Linus Torvalds
Jiqian Chen
David Hildenbrand
Chen Ni
Frediano Ziglio
Uros Bizjak
Thomas Gleixner
Ingo Molnar
Jiapeng Chong