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Message-ID: <20251126014455.788131-3-seanjc@google.com>
Date: Tue, 25 Nov 2025 17:44:49 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
Sean Christopherson <seanjc@...gle.com>
Subject: [GIT PULL] KVM: guest_memfd: NUMA support and other changes for 6.19
Please pull NUMA mempolicy guest_memfd support, along with a handful of
guest_memfd cleanups and some tangentially related additions to KVM selftests
infrastructure.
This will conflict with kvm/master due to commit ae431059e75d ("KVM:
guest_memfd: Remove bindings on memslot deletion when gmem is dying"). The
resolution I've been using for linux-next is below.
--
diff --cc virt/kvm/guest_memfd.c
index ffadc5ee8e04,427c0acee9d7..fdaea3422c30
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@@ -623,53 -708,31 +708,49 @@@ err
return r;
}
- static void __kvm_gmem_unbind(struct kvm_memory_slot *slot, struct kvm_gmem *gmem)
-void kvm_gmem_unbind(struct kvm_memory_slot *slot)
++static void __kvm_gmem_unbind(struct kvm_memory_slot *slot, struct gmem_file *f)
{
unsigned long start = slot->gmem.pgoff;
unsigned long end = start + slot->npages;
- struct gmem_file *f;
- xa_store_range(&gmem->bindings, start, end - 1, NULL, GFP_KERNEL);
- /*
- * Nothing to do if the underlying file was already closed (or is being
- * closed right now), kvm_gmem_release() invalidates all bindings.
- */
- CLASS(gmem_get_file, file)(slot);
- if (!file)
- return;
-
- f = file->private_data;
-
- filemap_invalidate_lock(file->f_mapping);
+ xa_store_range(&f->bindings, start, end - 1, NULL, GFP_KERNEL);
/*
* synchronize_srcu(&kvm->srcu) ensured that kvm_gmem_get_pfn()
* cannot see this memslot.
*/
WRITE_ONCE(slot->gmem.file, NULL);
+}
+
+void kvm_gmem_unbind(struct kvm_memory_slot *slot)
+{
- struct file *file;
-
+ /*
+ * Nothing to do if the underlying file was _already_ closed, as
+ * kvm_gmem_release() invalidates and nullifies all bindings.
+ */
+ if (!slot->gmem.file)
+ return;
+
- file = kvm_gmem_get_file(slot);
++ CLASS(gmem_get_file, file)(slot);
+
+ /*
+ * However, if the file is _being_ closed, then the bindings need to be
+ * removed as kvm_gmem_release() might not run until after the memslot
+ * is freed. Note, modifying the bindings is safe even though the file
+ * is dying as kvm_gmem_release() nullifies slot->gmem.file under
+ * slots_lock, and only puts its reference to KVM after destroying all
+ * bindings. I.e. reaching this point means kvm_gmem_release() hasn't
+ * yet destroyed the bindings or freed the gmem_file, and can't do so
+ * until the caller drops slots_lock.
+ */
+ if (!file) {
+ __kvm_gmem_unbind(slot, slot->gmem.file->private_data);
+ return;
+ }
+
+ filemap_invalidate_lock(file->f_mapping);
+ __kvm_gmem_unbind(slot, file->private_data);
filemap_invalidate_unlock(file->f_mapping);
-
- fput(file);
}
/* Returns a locked folio on success. */
The following changes since commit 211ddde0823f1442e4ad052a2f30f050145ccada:
Linux 6.18-rc2 (2025-10-19 15:19:16 -1000)
are available in the Git repository at:
https://github.com/kvm-x86/linux.git tags/kvm-x86-gmem-6.19
for you to fetch changes up to 83e0e12219a402bf7b8fdef067e51f945a92fd26:
KVM: selftests: Rename "guest_paddr" variables to "gpa" (2025-11-03 12:54:21 -0800)
----------------------------------------------------------------
KVM guest_memfd changes for 6.19:
- Add NUMA mempolicy support for guest_memfd, and clean up a variety of
rough edges in guest_memfd along the way.
- Define a CLASS to automatically handle get+put when grabbing a guest_memfd
from a memslot to make it harder to leak references.
- Enhance KVM selftests to make it easer to develop and debug selftests like
those added for guest_memfd NUMA support, e.g. where test and/or KVM bugs
often result in hard-to-debug SIGBUS errors.
- Misc cleanups.
----------------------------------------------------------------
Ackerley Tng (1):
KVM: guest_memfd: Use guest mem inodes instead of anonymous inodes
Matthew Wilcox (2):
mm/filemap: Add NUMA mempolicy support to filemap_alloc_folio()
mm/filemap: Extend __filemap_get_folio() to support NUMA memory policies
Pedro Demarchi Gomes (1):
KVM: guest_memfd: use folio_nr_pages() instead of shift operation
Sean Christopherson (10):
KVM: guest_memfd: Drop a superfluous local var in kvm_gmem_fault_user_mapping()
KVM: guest_memfd: Rename "struct kvm_gmem" to "struct gmem_file"
KVM: guest_memfd: Add macro to iterate over gmem_files for a mapping/inode
KVM: selftests: Define wrappers for common syscalls to assert success
KVM: selftests: Report stacktraces SIGBUS, SIGSEGV, SIGILL, and SIGFPE by default
KVM: selftests: Add additional equivalents to libnuma APIs in KVM's numaif.h
KVM: selftests: Use proper uAPI headers to pick up mempolicy.h definitions
KVM: guest_memfd: Add gmem_inode.flags field instead of using i_private
KVM: guest_memfd: Define a CLASS to get+put guest_memfd file from a memslot
KVM: selftests: Rename "guest_paddr" variables to "gpa"
Shivank Garg (7):
mm/mempolicy: Export memory policy symbols
KVM: guest_memfd: move kvm_gmem_get_index() and use in kvm_gmem_prepare_folio()
KVM: guest_memfd: remove redundant gmem variable initialization
KVM: guest_memfd: Add slab-allocated inode cache
KVM: guest_memfd: Enforce NUMA mempolicy using shared policy
KVM: selftests: Add helpers to probe for NUMA support, and multi-node systems
KVM: selftests: Add guest_memfd tests for mmap and NUMA policy support
fs/btrfs/compression.c | 4 +-
fs/btrfs/verity.c | 2 +-
fs/erofs/zdata.c | 2 +-
fs/f2fs/compress.c | 2 +-
include/linux/pagemap.h | 18 +++--
include/uapi/linux/magic.h | 1 +
mm/filemap.c | 23 ++++---
mm/mempolicy.c | 6 ++
mm/readahead.c | 2 +-
tools/testing/selftests/kvm/arm64/vgic_irq.c | 2 +-
tools/testing/selftests/kvm/guest_memfd_test.c | 98 +++++++++++++++++++++++++++
tools/testing/selftests/kvm/include/kvm_syscalls.h | 81 ++++++++++++++++++++++
tools/testing/selftests/kvm/include/kvm_util.h | 39 ++---------
tools/testing/selftests/kvm/include/numaif.h | 110 ++++++++++++++++++------------
tools/testing/selftests/kvm/kvm_binary_stats_test.c | 4 +-
tools/testing/selftests/kvm/lib/kvm_util.c | 101 +++++++++++++++-------------
tools/testing/selftests/kvm/x86/private_mem_conversions_test.c | 9 +--
tools/testing/selftests/kvm/x86/xapic_ipi_test.c | 5 +-
virt/kvm/guest_memfd.c | 374 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--------------------------
virt/kvm/kvm_main.c | 7 +-
virt/kvm/kvm_mm.h | 9 +--
21 files changed, 646 insertions(+), 253 deletions(-)
create mode 100644 tools/testing/selftests/kvm/include/kvm_syscalls.h
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