* [RFC PATCH 04/13] mm/damon/core: use damon_nr_accesses_mvsum() for damos region tracing
From: SeongJae Park @ 2026-06-19 19:33 UTC (permalink / raw)
Cc: SeongJae Park, Andrew Morton, Masami Hiramatsu, Mathieu Desnoyers,
Steven Rostedt, damon, linux-kernel, linux-mm, linux-trace-kernel
In-Reply-To: <20260619193415.73833-1-sj@kernel.org>
damon_nr_accesses_mvsum() returns a value same to nr_accesses_bp. Also
the function is more simple and therefore more tolerant to errors.
Execution of the function would be more expensive than the simple read
of the field, but because the function is quite simple, the overhead
should be negligible. Use it in the DAMON region exporting trace points
instead of the nr_accesses_bp.
Signed-off-by: SeongJae Park <sj@kernel.org>
---
include/trace/events/damon.h | 8 +++++---
mm/damon/core.c | 1 +
2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/include/trace/events/damon.h b/include/trace/events/damon.h
index 78388538acf44..8851727ae1627 100644
--- a/include/trace/events/damon.h
+++ b/include/trace/events/damon.h
@@ -78,9 +78,11 @@ TRACE_EVENT_CONDITION(damos_before_apply,
TP_PROTO(unsigned int context_idx, unsigned int scheme_idx,
unsigned int target_idx, struct damon_region *r,
- unsigned int nr_regions, bool do_trace),
+ unsigned int nr_accesses, unsigned int nr_regions,
+ bool do_trace),
- TP_ARGS(context_idx, scheme_idx, target_idx, r, nr_regions, do_trace),
+ TP_ARGS(context_idx, scheme_idx, target_idx, r, nr_accesses,
+ nr_regions, do_trace),
TP_CONDITION(do_trace),
@@ -101,7 +103,7 @@ TRACE_EVENT_CONDITION(damos_before_apply,
__entry->target_idx = target_idx;
__entry->start = r->ar.start;
__entry->end = r->ar.end;
- __entry->nr_accesses = r->nr_accesses_bp / 10000;
+ __entry->nr_accesses = nr_accesses;
__entry->age = r->age;
__entry->nr_regions = nr_regions;
),
diff --git a/mm/damon/core.c b/mm/damon/core.c
index 3a6df10ba8548..2eddf2674f4fa 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -2463,6 +2463,7 @@ static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
return;
ktime_get_coarse_ts64(&begin);
trace_damos_before_apply(cidx, sidx, tidx, r,
+ damon_nr_accesses_mvsum(r, c),
damon_nr_regions(t), do_trace);
sz_applied = c->ops.apply_scheme(c, t, r, s,
&sz_ops_filter_passed);
--
2.47.3
^ permalink raw reply related
* [RFC PATCH 00/13] mm/damon: optimize out nr_accesses_bp
From: SeongJae Park @ 2026-06-19 19:33 UTC (permalink / raw)
Cc: SeongJae Park, Andrew Morton, Brendan Higgins, David Gow,
Masami Hiramatsu, Mathieu Desnoyers, Shuah Khan, Steven Rostedt,
damon, kunit-dev, linux-kernel, linux-kselftest, linux-mm,
linux-trace-kernel
TLDR: Replace damon_region->nr_accesses_bp, which is easy to be wrong,
with a simpler on-demand moving sum function, damon_nr_accesses_mvsum().
Background
==========
DAMON's monitoring output (access pattern snapshot, or more technically
speaking, damon_region->nr_accesses) is completed once per aggregation
interval, which is 100 ms by default. Users can arbitrarily increase
the interval for demand. Under the suggested intervals auto-tuning
setup, it can span up to 200 seconds. If the aggregation interval is
too long, the snapshot users cannot use it in reasonable time. To
mitigate this, we introduced a new field of damon_region, namely
nr_accesses_bp. It contains a pseudo moving sum of nr_accesses in bp
units and is updated for each sampling interval.
It turned out keeping it correctly updated every sampling interval is
not that easy. From online parameter update feature development and
more experimental hacks, we found it is easy to be corrupted. Once it
is corrupted, DAMON's monitoring outputs become quite insane. Hence we
added a few validation checks. It is easy to be corrupted because it
requires every update per sampling interval to be correct.
Solution
========
There is no real reason to keep it updated every sampling interval. Due
to the simple pseudo-moving sum mechanism and existing helper field
(last_nr_accesses), we can also calculate the pseudo moving sum on
demand in a much simpler way.
Implement a function for getting the pseudo moving sum on demand, and
replace nr_accessses_bp uses with the new function. Also remove no more
needed tests for nr_accesses_bp and the per-sampling interval update
functions. Finally, remove the nr_accesses_bp. The new function is
quite simple.
Discussion
==========
Depending on the use case, multiple nr_accesses readers could be
executed in the same kdamond_fn() main loop iteration, which is executed
once per sampling interval. Such readers include DAMON region exporting
tracepoints (damon_[region_]aggregated and damos_before_apply), DAMOS,
and DAMON sysfs interface logic for update_schemes_tried_regions
command. In this case, the new function will be called multiple times
and this could be overhead compared to the old logic, which simply reads
the field without any additional work. Nonetheless, the new function is
quite simple. And the new approach does nothing while there is no need
to read. The old approach had to execute its update function for each
region for every sampling interval. Hence the new approach is believed
to be even more lightweight in common case, and the overhead is anyway
negligible.
One more advantage of this change is that one field from the
damon_region struct is removed. On setups that uses a high number of
DAMON regions, this could be a potential memory space benefit.
Patches Sequence
================
Patch 1 introduces the new function for getting the pseudo moving sum of
nr_accesses on demands. Patch 2 implements a unit test for the new
function's internal logic. Patches 3-5 replace uses of nr_accesses_bp
in DAMOS, tracepoints and DAMON sysfs interface with the new function,
respectively. Patches 6-8 removes nr_accesses_bp validation functions
in DAMON core, one by one. Patches 9 and 10 further remove tests and
test helper for nr_accesses_bp, respectively. Patches 11 removes the
setups and updates or nr_accesses_bp field. Patch 12 removes the
function that was used for updating nr_accesses_bp field with its unit
test, which is the single remaining caller of the function. Finally,
patch 13 removes damon_region->nr_accesses_bp field.
SeongJae Park (13):
mm/damon: introduce damon_nr_accesses_mvsum()
mm/damon/tests/core-kunit: test damon_mvsum()
mm/damon/core: use damon_nr_accesses_mvsum() in __damos_valid_target()
mm/damon/core: use damon_nr_accesses_mvsum() for damos region tracing
mm/damon/sysfs-schemes: use damon_nr_accesses_mvsum() for damo regions
mm/damon/core: remove damon_warn_fix_nr_accesses_corruption()
mm/damon/core: remove damon_verify_reset_aggregated()
mm/damon/core: remove damon_verify_merge_regions_of()
mm/damon/tests/core-kunit: remove nr_accesses_bp setup and tests
selftests/damon/drgn_dump_damon_status: do not dump nr_accesses_bp
mm/damon/core: remove nr_accesses_bp setups and updates
mm/damon/core: remove damon_moving_sum() and its unit test
mm/damon: remove damon_region->nr_accesses_bp
include/linux/damon.h | 12 +-
include/trace/events/damon.h | 8 +-
mm/damon/core.c | 171 +++++++-----------
mm/damon/sysfs-schemes.c | 6 +-
mm/damon/tests/core-kunit.h | 37 ++--
.../selftests/damon/drgn_dump_damon_status.py | 1 -
6 files changed, 91 insertions(+), 144 deletions(-)
base-commit: 6c6dd09066e98c4afcf61f404d5b2b87f35e3321
--
2.47.3
^ permalink raw reply
* [PATCH] tracing/fprobe: Fix NULL pointer dereference in fprobe_fgraph_entry()
From: Sechang Lim @ 2026-06-19 18:44 UTC (permalink / raw)
To: Steven Rostedt, Masami Hiramatsu
Cc: Mathieu Desnoyers, Heiko Carstens, linux-kernel,
linux-trace-kernel
fprobe_fgraph_entry() sizes a shadow-stack reservation in one walk of
the per-ip fprobe list and fills it in a second walk, both under
rcu_read_lock() only. A fprobe registered on an already-live ip can
become visible between the two walks, so the fill walk processes an
exit_handler the sizing walk did not count and used runs past
reserved_words. If the sizing walk counted nothing, fgraph_data is NULL
and the first write_fprobe_header() faults:
Oops: general protection fault, probably for non-canonical address ...
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
RIP: 0010:fprobe_fgraph_entry+0xa38/0xf10 kernel/trace/fprobe.c:167
Call Trace:
<TASK>
function_graph_enter_regs+0x44c/0xa10 kernel/trace/fgraph.c:677
ftrace_graph_func+0xc5/0x140 arch/x86/kernel/ftrace.c:671
__kernel_text_address+0x9/0x40 kernel/extable.c:78
arch_stack_walk+0x117/0x170 arch/x86/kernel/stacktrace.c:26
kmem_cache_free+0x188/0x580 mm/slub.c:6378
tcp_data_queue+0x18d/0x6550 net/ipv4/tcp_input.c:5590
[...]
</TASK>
The list cannot be frozen across the two walks, so skip a node that does
not fit the reservation and count it as missed.
Fixes: 4346ba160409 ("fprobe: Rewrite fprobe on function-graph tracer")
Signed-off-by: Sechang Lim <rhkrqnwk98@gmail.com>
---
kernel/trace/fprobe.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index f378613ad120..f215990b9061 100644
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -613,6 +613,16 @@ static int fprobe_fgraph_entry(struct ftrace_graph_ent *trace, struct fgraph_ops
continue;
data_size = fp->entry_data_size;
+ /*
+ * The list may have grown since it was sized, so this node
+ * may not fit. Skip it as missed rather than overrun the
+ * reservation.
+ */
+ if (fp->exit_handler &&
+ used + FPROBE_HEADER_SIZE_IN_LONG + SIZE_IN_LONG(data_size) > reserved_words) {
+ fp->nmissed++;
+ continue;
+ }
if (data_size && fp->exit_handler)
data = fgraph_data + used + FPROBE_HEADER_SIZE_IN_LONG;
else
--
2.43.0
^ permalink raw reply related
* [PATCH] kprobes: Replace __ASSEMBLY__ with __ASSEMBLER__ in header file
From: Thomas Huth @ 2026-06-19 16:14 UTC (permalink / raw)
To: Naveen N Rao, David S. Miller, Masami Hiramatsu
Cc: linux-kernel, linux-trace-kernel, linux-arch
From: Thomas Huth <thuth@redhat.com>
While the GCC and Clang compilers already define __ASSEMBLER__
automatically when compiling assembly code, __ASSEMBLY__ is a
macro that only gets defined by the Makefiles in the kernel.
This can be very confusing when switching between userspace
and kernelspace coding, or when dealing with uapi headers that
rather should use __ASSEMBLER__ instead. So let's standardize now
on the __ASSEMBLER__ macro that is provided by the compilers.
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
Note: This patch has been split from an earlier bigger patch of
mine to ease reviewing.
include/asm-generic/kprobes.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/asm-generic/kprobes.h b/include/asm-generic/kprobes.h
index 5290a2b2e15a0..16f16963d503d 100644
--- a/include/asm-generic/kprobes.h
+++ b/include/asm-generic/kprobes.h
@@ -2,7 +2,7 @@
#ifndef _ASM_GENERIC_KPROBES_H
#define _ASM_GENERIC_KPROBES_H
-#if defined(__KERNEL__) && !defined(__ASSEMBLY__)
+#if defined(__KERNEL__) && !defined(__ASSEMBLER__)
#ifdef CONFIG_KPROBES
/*
* Blacklist ganerating macro. Specify functions which is not probed
@@ -21,6 +21,6 @@ static unsigned long __used \
# define __kprobes
# define nokprobe_inline inline
#endif
-#endif /* defined(__KERNEL__) && !defined(__ASSEMBLY__) */
+#endif /* defined(__KERNEL__) && !defined(__ASSEMBLER__) */
#endif /* _ASM_GENERIC_KPROBES_H */
--
2.54.0
^ permalink raw reply related
* Re: [PATCH v8 05/46] KVM: Make CONFIG_KVM_VM_MEMORY_ATTRIBUTES selectable
From: Julian Braha @ 2026-06-19 12:51 UTC (permalink / raw)
To: ackerleytng, aik, andrew.jones, binbin.wu, brauner, chao.p.peng,
david, jmattson, jthoughton, michael.roth, oupton, pankaj.gupta,
qperret, rick.p.edgecombe, rientjes, shivankg, steven.price,
tabba, willy, wyihan, yan.y.zhao, forkloop, pratyush,
suzuki.poulose, aneesh.kumar, liam, Paolo Bonzini,
Sean Christopherson, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, Dave Hansen, x86, H. Peter Anvin, Steven Rostedt,
Masami Hiramatsu, Mathieu Desnoyers, Jonathan Corbet, Shuah Khan,
Shuah Khan, Vishal Annapurve, Andrew Morton, Chris Li,
Kairui Song, Kemeng Shi, Nhat Pham, Barry Song, Axel Rasmussen,
Yuanchu Xie, Wei Xu, Youngjun Park, Qi Zheng, Shakeel Butt,
Kiryl Shutsemau, Baoquan He, Jason Gunthorpe, Vlastimil Babka
Cc: kvm, linux-kernel, linux-trace-kernel, linux-doc, linux-kselftest,
linux-mm, linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-5-9d2959357853@google.com>
Hi Ackerley,
On 6/19/26 01:31, Ackerley Tng via B4 Relay wrote:
> config KVM_VM_MEMORY_ATTRIBUTES
> - bool
> + depends on KVM_SW_PROTECTED_VM || KVM_INTEL_TDX || KVM_AMD_SEV
> + bool "Enable per-VM PRIVATE vs. SHARED attributes (for CoCo VMs)"
Sorry for the style nitpick, but could you keep the type and prompt as
the first attribute in the Kconfig option definition (like the other
options do)?
- Julian Braha
^ permalink raw reply
* Re: [PATCH v8 00/46] guest_memfd: In-place conversion support
From: Garg, Shivank @ 2026-06-19 12:28 UTC (permalink / raw)
To: ackerleytng, aik, andrew.jones, binbin.wu, brauner, chao.p.peng,
david, jmattson, jthoughton, michael.roth, oupton, pankaj.gupta,
qperret, rick.p.edgecombe, rientjes, steven.price, tabba, willy,
wyihan, yan.y.zhao, forkloop, pratyush, suzuki.poulose,
aneesh.kumar, liam, Paolo Bonzini, Sean Christopherson,
Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, x86,
H. Peter Anvin, Steven Rostedt, Masami Hiramatsu,
Mathieu Desnoyers, Jonathan Corbet, Shuah Khan, Shuah Khan,
Vishal Annapurve, Andrew Morton, Chris Li, Kairui Song,
Kemeng Shi, Nhat Pham, Barry Song, Axel Rasmussen, Yuanchu Xie,
Wei Xu, Youngjun Park, Qi Zheng, Shakeel Butt, Kiryl Shutsemau,
Baoquan He, Jason Gunthorpe, Vlastimil Babka
Cc: kvm, linux-kernel, linux-trace-kernel, linux-doc, linux-kselftest,
linux-mm, linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-0-9d2959357853@google.com>
On 6/19/2026 6:01 AM, Ackerley Tng via B4 Relay wrote:
> This is v8 of guest_memfd in-place conversion support.
>
> Up till now, guest_memfd supports the entire inode worth of memory being
> used as all-shared, or all-private. CoCo VMs may request guest memory to be
> converted between private and shared states, and the only way to support
> that currently would be to have the userspace VMM provide two sources of
> backing memory from completely different areas of physical memory.
>
> pKVM has a use case for in-place sharing: the guest and host may be
> cooperating on given data, and pKVM doesn't protect data through
> encryption, so copying that given data between different areas of physical
> memory as part of conversions would be unnecessary work.
>
> This series also serves as a foundation for guest_memfd huge page
> support. Now, guest_memfd only supports PAGE_SIZE pages, so if two sources
> of backing memory are used, the userspace VMM could maintain a steady total
> memory utilized by punching out the pages that are not used. When huge
> pages are available in guest_memfd, even if the backing memory source
> supports hole punching within a huge page, punching out pages to maintain
> the total memory utilized by a VM would be introducing lots of
> fragmentation.
>
> In-place conversion avoids fragmentation by allowing the same physical
> memory to be used for both shared and private memory, with guest_memfd
> tracks the shared/private status of all the pages at a per-page
> granularity.
>
> The central principle, which guest_memfd continues to uphold, is that any
> guest-private page will not be mappable to host userspace. All pages will
> be mmap()-able in host userspace, but accesses to guest-private pages (as
> tracked by guest_memfd) will result in a SIGBUS.
>
> This series introduces a guest_memfd ioctl (not kvm, vm or vcpu, but
> guest_memfd ioctl) that allows userspace to set memory
> attributes (shared/private) directly through the guest_memfd. This is the
> appropriate interface because shared/private-ness is a property of memory
> and hence the request should be sent directly to the memory provider -
> guest_memfd.
>
> Tested with both CONFIG_KVM_VM_MEMORY_ATTRIBUTES enabled and disabled:
>
> + tools/testing/selftests/kvm/guest_memfd_test.c
> + tools/testing/selftests/kvm/pre_fault_memory_test.c
> + tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
> + tools/testing/selftests/kvm/x86/private_mem_conversions_test.c
> + tools/testing/selftests/kvm/x86/private_mem_kvm_exits_test.c
>
> Updates for this revision:
>
> + Updated the series to _not_ deprecate all of VM memory attributes, but
> only deprecate tracking of the PRIVATE attributes in VM memory
> attributes. This takes into account upcoming RWX attributes support,
> which will be tracked at the VM level.
> + Reshuffled the earlier commits that deal with preparing KVM to stop
> seeing VM memory attributes as the only source of attributes.
> + Addressed comments from v7
>
> TODOs
>
> + Retest with TDX selftests. v7 was tested with TDX [12], but the setup there was
> wrong. Conversions were successful (no errors), but the shared memory being
> tested is actually in a completely different host physical page.
> + Retest with SNP selftests. v6 was tested with SNP, I ported that to v7
> and those ran fine too. Just need to double-check for v8.
>
> This series is based on kvm-x86/next, and here's the tree for your convenience:
>
> https://github.com/googleprodkernel/linux-cc/commits/guest_memfd-inplace-conversion-v8
>
> Older series:
>
> + RFCv7 is at [11]
> + RFCv6 is at [10]
> + RFCv5 is at [8]
> + RFCv4 is at [7]
> + RFCv3 is at [6]
> + RFCv2 is at [5]
> + RFCv1 is at [4]
> + Previous versions of this feature, part of other series, are available at
> [1][2][3].
>
> [1] https://lore.kernel.org/all/bd163de3118b626d1005aa88e71ef2fb72f0be0f.1726009989.git.ackerleytng@google.com/
> [2] https://lore.kernel.org/all/20250117163001.2326672-6-tabba@google.com/
> [3] https://lore.kernel.org/all/b784326e9ccae6a08388f1bf39db70a2204bdc51.1747264138.git.ackerleytng@google.com/
> [4] https://lore.kernel.org/all/cover.1760731772.git.ackerleytng@google.com/T/
> [5] https://lore.kernel.org/all/cover.1770071243.git.ackerleytng@google.com/T/
> [6] https://lore.kernel.org/r/20260313-gmem-inplace-conversion-v3-0-5fc12a70ec89@google.com/T/
> [7] https://lore.kernel.org/all/20260326-gmem-inplace-conversion-v4-0-e202fe950ffd@google.com/T/
> [8] https://lore.kernel.org/r/20260428-gmem-inplace-conversion-v5-0-d8608ccfca22@google.com
> [9] https://lore.kernel.org/all/20260414-selftest-global-metadata-v1-0-fd223922bc57@google.com/T/
> [10] https://lore.kernel.org/r/20260507-gmem-inplace-conversion-v6-0-91ab5a8b19a4@google.com
> [11] https://lore.kernel.org/r/20260522-gmem-inplace-conversion-v7-0-2f0fae496530@google.com
> [12] https://lore.kernel.org/all/20260605134153.204152-1-ackerleytng@google.com/
>
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
> ---
> Ackerley Tng (27):
> KVM: Make CONFIG_KVM_VM_MEMORY_ATTRIBUTES selectable
> KVM: Enumerate support for PRIVATE memory iff kvm_arch_has_private_mem is defined
> KVM: guest_memfd: Introduce function to check GFN private/shared status
> KVM: guest_memfd: Only prepare folios for private pages
> KVM: guest_memfd: Add base support for KVM_SET_MEMORY_ATTRIBUTES2
> KVM: guest_memfd: Ensure pages are not in use before conversion
> KVM: guest_memfd: Call arch invalidate hooks on conversion
> KVM: guest_memfd: Return early if range already has requested attributes
> KVM: guest_memfd: Advertise KVM_SET_MEMORY_ATTRIBUTES2 ioctl
> KVM: guest_memfd: Handle lru_add fbatch refcounts during conversion safety check
> KVM: guest_memfd: Use actual size for invalidation in kvm_gmem_release()
> KVM: guest_memfd: Determine invalidation filter from memory attributes
> KVM: guest_memfd: Zero page while getting pfn
> KVM: TDX: Make source page optional for KVM_TDX_INIT_MEM_REGION
> KVM: guest_memfd: Make in-place conversion the default
> KVM: selftests: Test basic single-page conversion flow
> KVM: selftests: Test conversion flow when INIT_SHARED
> KVM: selftests: Test conversion precision in guest_memfd
> KVM: selftests: Test conversion before allocation
> KVM: selftests: Convert with allocated folios in different layouts
> KVM: selftests: Test that truncation does not change shared/private status
> KVM: selftests: Add helpers to pin pages with CONFIG_GUP_TEST
> KVM: selftests: Test conversion with elevated page refcount
> KVM: selftests: Reset shared memory after hole-punching
> KVM: selftests: Provide function to look up guest_memfd details from gpa
> KVM: selftests: Make TEST_EXPECT_SIGBUS thread-safe
> KVM: selftests: Update private_mem_conversions_test to mmap() guest_memfd
>
> Michael Roth (1):
> KVM: SEV: Make 'uaddr' parameter optional for KVM_SEV_SNP_LAUNCH_UPDATE
>
> Sean Christopherson (18):
> KVM: guest_memfd: Introduce per-gmem attributes, use to guard user mappings
> KVM: Rename KVM_GENERIC_MEMORY_ATTRIBUTES to KVM_VM_MEMORY_ATTRIBUTES
> KVM: Move KVM_VM_MEMORY_ATTRIBUTES config definition to x86
> KVM: Decouple kvm_has_arch_private_mem from CONFIG_KVM_VM_MEMORY_ATTRIBUTES
> KVM: Rename memory attribute APIs to prepare for in-place gmem conversion
> KVM: Provide generic interface for checking memory private/shared status
> KVM: guest_memfd: Wire up core private/shared attribute interfaces
> KVM: Consolidate private memory and guest_memfd ifdeffery in kvm_host.h
> KVM: guest_memfd: Enable INIT_SHARED on guest_memfd for x86 Coco VMs
> KVM: selftests: Create gmem fd before "regular" fd when adding memslot
> KVM: selftests: Rename guest_memfd{,_offset} to gmem_{fd,offset}
> KVM: selftests: Add support for mmap() on guest_memfd in core library
> KVM: selftests: Add selftests global for guest memory attributes capability
> KVM: selftests: Add helpers for calling ioctls on guest_memfd
> KVM: selftests: Test that shared/private status is consistent across processes
> KVM: selftests: Provide common function to set memory attributes
> KVM: selftests: Check fd/flags provided to mmap() when setting up memslot
> KVM: selftests: Update private memory exits test to work with per-gmem attributes
>
Hi,
Thanks for this series.
This works well for me on AMD EPYC 7713 (SEV-SNP enabled). I tested:
1. KVM selftests: all tests pass.
2. Using in-place conversion QEMU branch [1]:
qemu-system-x86_64 \
-machine q35,confidential-guest-support=sev0 \
-enable-kvm -cpu EPYC-v4 -smp 8,maxcpus=8 -m 120G -no-reboot \
-object memory-backend-guest-memfd,id=ram0,size=60G,share=on,host-nodes=0-1,policy=interleave \
-object memory-backend-guest-memfd,id=ram1,size=60G,share=on,host-nodes=0,policy=bind \
-numa node,nodeid=0,memdev=ram0,cpus=0-3 \
-numa node,nodeid=1,memdev=ram1,cpus=4-7 \
-object sev-snp-guest,id=sev0,policy=0x30000,cbitpos=51,reduced-phys-bits=1,convert-in-place=on \
-bios "$OVMF" \
-drive file="$DISK",if=none,id=disk0,format=qcow2 \
-device virtio-scsi-pci,id=scsi0,disable-legacy=on,iommu_platform=true -device scsi-hd,drive=disk0 \
-netdev user,id=net0,hostfwd=tcp::8000-:22 -device virtio-net-pci,netdev=net0 \
-kernel "$KERNEL" -initrd "$INITRD" \
-append "$ROOT ro console=ttyS0,115200" \
-trace enable=kvm_convert_memory,file=/tmp/convert.log \
-nographic -serial mon:stdio
The guest boots successfully and run memory hogger. With this, I verified the
shared <-> private conversion logs (trace_kvm_convert_memory).
3. Additionally, verified the NUMA placement for SEV-SNP. With this series,
NUMA mempolicy support for guest_memfd [2] now works for SEV-SNP as well.
[1] https://github.com/amdese/qemu/commits/snp-inplace-rfc1
[2] https://lore.kernel.org/kvm/20251016172853.52451-1-seanjc@google.com
Tested-by: Shivank Garg <shivankg@amd.com>
Best regards,
Shivank
^ permalink raw reply
* Re: [PATCH v8 23/46] KVM: TDX: Make source page optional for KVM_TDX_INIT_MEM_REGION
From: Fuad Tabba @ 2026-06-19 11:09 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-23-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:31, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Ackerley Tng <ackerleytng@google.com>
>
> Update tdx_gmem_post_populate() to handle cases where a source page is
> not explicitly provided. Instead of returning -EOPNOTSUPP when src_page
> is NULL, default to using the page associated with the destination PFN.
>
> This change allows for in-place memory conversion where the data is
> already present in the target PFN, ensuring the TDX module has a valid
> source page reference for the TDH.MEM.PAGE.ADD operation.
>
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
Sashiko flagged that when src_page = pfn_to_page(pfn),
tdh_mem_page_add gets identical physical addresses for r8
(destination) and r9 (source), reading with host KeyID and writing
with TD KeyID on the same address. I don't know enough about the TDX
module's operand constraints to confirm whether it allows overlapping
source and destination, but the concern looks legitimate.
nit: why does it have Sean's SoB?
Cheers,
/fuad
> Documentation/virt/kvm/x86/intel-tdx.rst | 4 ++++
> arch/x86/kvm/vmx/tdx.c | 11 ++++++++---
> 2 files changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/virt/kvm/x86/intel-tdx.rst b/Documentation/virt/kvm/x86/intel-tdx.rst
> index 6a222e9d09541..74357fe87f9ec 100644
> --- a/Documentation/virt/kvm/x86/intel-tdx.rst
> +++ b/Documentation/virt/kvm/x86/intel-tdx.rst
> @@ -158,6 +158,10 @@ KVM_TDX_INIT_MEM_REGION
> Initialize @nr_pages TDX guest private memory starting from @gpa with userspace
> provided data from @source_addr. @source_addr must be PAGE_SIZE-aligned.
>
> +If guest_memfd in-place conversion is enabled, pass NULL for @source_addr to
> +initialize the memory region using memory contents already populated in
> +guest_memfd memory.
> +
> Note, before calling this sub command, memory attribute of the range
> [gpa, gpa + nr_pages] needs to be private. Userspace can use
> KVM_SET_MEMORY_ATTRIBUTES to set the attribute.
> diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
> index ffe9d0db58c59..56d10333c61a7 100644
> --- a/arch/x86/kvm/vmx/tdx.c
> +++ b/arch/x86/kvm/vmx/tdx.c
> @@ -3198,8 +3198,12 @@ static int tdx_gmem_post_populate(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn,
> if (KVM_BUG_ON(kvm_tdx->page_add_src, kvm))
> return -EIO;
>
> - if (!src_page)
> - return -EOPNOTSUPP;
> + if (!src_page) {
> + if (!gmem_in_place_conversion)
> + return -EOPNOTSUPP;
> +
> + src_page = pfn_to_page(pfn);
> + }
>
> kvm_tdx->page_add_src = src_page;
> ret = kvm_tdp_mmu_map_private_pfn(arg->vcpu, gfn, pfn);
> @@ -3278,7 +3282,8 @@ static int tdx_vcpu_init_mem_region(struct kvm_vcpu *vcpu, struct kvm_tdx_cmd *c
> break;
> }
>
> - region.source_addr += PAGE_SIZE;
> + if (region.source_addr)
> + region.source_addr += PAGE_SIZE;
> region.gpa += PAGE_SIZE;
> region.nr_pages--;
>
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v8 11/46] KVM: Consolidate private memory and guest_memfd ifdeffery in kvm_host.h
From: Fuad Tabba @ 2026-06-19 11:02 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-11-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:31, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Sean Christopherson <seanjc@google.com>
>
> Move the kvm_arch_has_private_mem() stub and a few guest_memfd function
> definitions/declarations "down" in kvm_host.h to utilize existing #ifdefs,
> and so that related code is clustered together.
>
> No functional change intended.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
SoB fix please. With that...
Reviewed-by: Fuad Tabba <tabba@google.com>
Cheers,
/fuad
> ---
> include/linux/kvm_host.h | 37 ++++++++++++++++---------------------
> 1 file changed, 16 insertions(+), 21 deletions(-)
>
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index acb552745b428..9c1cf1a6559e3 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -722,27 +722,6 @@ static inline int kvm_arch_vcpu_memslots_id(struct kvm_vcpu *vcpu)
> }
> #endif
>
> -#ifndef kvm_arch_has_private_mem
> -static inline bool kvm_arch_has_private_mem(struct kvm *kvm)
> -{
> - return false;
> -}
> -#endif
> -
> -#ifdef CONFIG_KVM_GUEST_MEMFD
> -bool kvm_arch_supports_gmem_init_shared(struct kvm *kvm);
> -
> -static inline u64 kvm_gmem_get_supported_flags(struct kvm *kvm)
> -{
> - u64 flags = GUEST_MEMFD_FLAG_MMAP;
> -
> - if (!kvm || kvm_arch_supports_gmem_init_shared(kvm))
> - flags |= GUEST_MEMFD_FLAG_INIT_SHARED;
> -
> - return flags;
> -}
> -#endif
> -
> #ifndef kvm_arch_has_readonly_mem
> static inline bool kvm_arch_has_readonly_mem(struct kvm *kvm)
> {
> @@ -2572,6 +2551,11 @@ static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
> #else
> #define gmem_in_place_conversion false
>
> +static inline bool kvm_arch_has_private_mem(struct kvm *kvm)
> +{
> + return false;
> +}
> +
> static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
> {
> return false;
> @@ -2580,6 +2564,17 @@ static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
>
> #ifdef CONFIG_KVM_GUEST_MEMFD
> bool kvm_gmem_is_private(struct kvm *kvm, gfn_t gfn);
> +bool kvm_arch_supports_gmem_init_shared(struct kvm *kvm);
> +
> +static inline u64 kvm_gmem_get_supported_flags(struct kvm *kvm)
> +{
> + u64 flags = GUEST_MEMFD_FLAG_MMAP;
> +
> + if (!kvm || kvm_arch_supports_gmem_init_shared(kvm))
> + flags |= GUEST_MEMFD_FLAG_INIT_SHARED;
> +
> + return flags;
> +}
>
> int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
> gfn_t gfn, kvm_pfn_t *pfn, struct page **page,
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v8 22/46] KVM: SEV: Make 'uaddr' parameter optional for KVM_SEV_SNP_LAUNCH_UPDATE
From: Fuad Tabba @ 2026-06-19 11:01 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-22-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:31, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Michael Roth <michael.roth@amd.com>
>
> Make the source page for populating an SNP guest_memfd instance optional
> if in-place conversion/population is enabled. If KVM can convert the page
> in-place, then it's possible for guest memory to be initialized directly
> from userspace by mmap()'ing the guest_memfd and writing to it while the
> corresponding GPA ranges are in a 'shared' state, before converting them
> to the 'private' state expected by KVM_SEV_SNP_LAUNCH_UPDATE.
>
> Update the handling/documentation for KVM_SEV_SNP_LAUNCH_UPDATE to allow
> for 'uaddr' to be set to NULL when in-place conversion is enabled, which
> SNP_LAUNCH_UPDATE will then use to determine when it should/shouldn't
> copy in data from a separate memory location. Continue to enforce
> non-NULL when PRIVATE is tracked per-VM, not per-guest_memfd.
>
> Signed-off-by: Michael Roth <michael.roth@amd.com>
> [Added src_page check in error handling path when the firmware command fails]
> [Dropped ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES]
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
> [sean: drop explicit vm_memory_attributes references]
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
> Documentation/virt/kvm/x86/amd-memory-encryption.rst | 13 +++++++++----
> arch/x86/kvm/svm/sev.c | 16 +++++++++++-----
> virt/kvm/kvm_main.c | 1 +
> 3 files changed, 21 insertions(+), 9 deletions(-)
>
> diff --git a/Documentation/virt/kvm/x86/amd-memory-encryption.rst b/Documentation/virt/kvm/x86/amd-memory-encryption.rst
> index bd04a908a8dbd..29409297f1ef0 100644
> --- a/Documentation/virt/kvm/x86/amd-memory-encryption.rst
> +++ b/Documentation/virt/kvm/x86/amd-memory-encryption.rst
> @@ -503,7 +503,8 @@ secrets.
>
> It is required that the GPA ranges initialized by this command have had the
> KVM_MEMORY_ATTRIBUTE_PRIVATE attribute set in advance. See the documentation
> -for KVM_SET_MEMORY_ATTRIBUTES for more details on this aspect.
> +for KVM_SET_MEMORY_ATTRIBUTES/KVM_SET_MEMORY_ATTRIBUTES2 for more details on
> +this aspect.
>
> Upon success, this command is not guaranteed to have processed the entire
> range requested. Instead, the ``gfn_start``, ``uaddr``, and ``len`` fields of
> @@ -511,9 +512,13 @@ range requested. Instead, the ``gfn_start``, ``uaddr``, and ``len`` fields of
> remaining range that has yet to be processed. The caller should continue
> calling this command until those fields indicate the entire range has been
> processed, e.g. ``len`` is 0, ``gfn_start`` is equal to the last GFN in the
> -range plus 1, and ``uaddr`` is the last byte of the userspace-provided source
> -buffer address plus 1. In the case where ``type`` is KVM_SEV_SNP_PAGE_TYPE_ZERO,
> -``uaddr`` will be ignored completely.
> +range plus 1, and ``uaddr`` (if specified) is the last byte of the
> +userspace-provided source buffer address plus 1.
> +
> +In the case where ``type`` is KVM_SEV_SNP_PAGE_TYPE_ZERO, ``uaddr`` will be
> +ignored completely. For all other page types, ``uaddr`` is optional if in-place
> +conversion is enable, i.e. when the destination can also be the source, and is
Typo: "is enable" -> "is enabled".
"when the destination can also be the source" is hard to parse without
context. Maybe: "i.e. when the data has been written directly to
guest_memfd while the range was in the shared state".
Also, how does userspace discover whether in-place conversion is
enabled? A cross-reference to KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES
would help here.
Cheers,
/fuad
> +required if in-place conversion is disabled.
>
> Parameters (in): struct kvm_sev_snp_launch_update
>
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index 74fb15551e83f..2b7569b6a8609 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -2330,7 +2330,13 @@ static int sev_gmem_post_populate(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn,
> int level;
> int ret;
>
> - if (WARN_ON_ONCE(sev_populate_args->type != KVM_SEV_SNP_PAGE_TYPE_ZERO && !src_page))
> + /*
> + * A source page is required if in-place conversion isn't enabled, as
> + * the data needs to come from a separate physical page. Zero pages
> + * are exempt as they don't consume a source page.
> + */
> + if (!gmem_in_place_conversion &&
> + sev_populate_args->type != KVM_SEV_SNP_PAGE_TYPE_ZERO && !src_page)
> return -EINVAL;
>
> ret = snp_lookup_rmpentry((u64)pfn, &assigned, &level);
> @@ -2377,7 +2383,7 @@ static int sev_gmem_post_populate(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn,
> */
> if (ret && !snp_page_reclaim(kvm, pfn) &&
> sev_populate_args->type == KVM_SEV_SNP_PAGE_TYPE_CPUID &&
> - sev_populate_args->fw_error == SEV_RET_INVALID_PARAM) {
> + sev_populate_args->fw_error == SEV_RET_INVALID_PARAM && src_page) {
> void *src_vaddr = kmap_local_page(src_page);
> void *dst_vaddr = kmap_local_pfn(pfn);
>
> @@ -2410,8 +2416,8 @@ static int snp_launch_update(struct kvm *kvm, struct kvm_sev_cmd *argp)
> if (copy_from_user(¶ms, u64_to_user_ptr(argp->data), sizeof(params)))
> return -EFAULT;
>
> - pr_debug("%s: GFN start 0x%llx length 0x%llx type %d flags %d\n", __func__,
> - params.gfn_start, params.len, params.type, params.flags);
> + pr_debug("%s: GFN start 0x%llx length 0x%llx type %d flags %d src %llx\n", __func__,
> + params.gfn_start, params.len, params.type, params.flags, params.uaddr);
>
> if (!params.len || !PAGE_ALIGNED(params.len) || params.flags ||
> (params.type != KVM_SEV_SNP_PAGE_TYPE_NORMAL &&
> @@ -2468,7 +2474,7 @@ static int snp_launch_update(struct kvm *kvm, struct kvm_sev_cmd *argp)
>
> params.gfn_start += count;
> params.len -= count * PAGE_SIZE;
> - if (params.type != KVM_SEV_SNP_PAGE_TYPE_ZERO)
> + if (src && params.type != KVM_SEV_SNP_PAGE_TYPE_ZERO)
> params.uaddr += count * PAGE_SIZE;
>
> if (copy_to_user(u64_to_user_ptr(argp->data), ¶ms, sizeof(params)))
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 044486f128c37..dd1d18a1d2f68 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -103,6 +103,7 @@ module_param(allow_unsafe_mappings, bool, 0444);
>
> #ifdef kvm_arch_has_private_mem
> bool __ro_after_init gmem_in_place_conversion = false;
> +EXPORT_SYMBOL_FOR_KVM_INTERNAL(gmem_in_place_conversion);
> #endif
>
> #define MEMORY_ATTRIBUTES_MATCH(one, two) \
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v8 21/46] KVM: guest_memfd: Zero page while getting pfn
From: Fuad Tabba @ 2026-06-19 10:51 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-21-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:31, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Ackerley Tng <ackerleytng@google.com>
>
> Move the folio initialization logic from kvm_gmem_get_pfn() into
> __kvm_gmem_get_pfn() to also zero pages if the page is to be used in
> kvm_gmem_populate().
>
> With in-place conversion, the existing data in a guest_memfd page can be
> populated into guest memory through platform-specific ioctls.
>
> Without first zeroing the page obtained using __kvm_gmem_get_pfn(), it
> might contain uninitialized host memory, which would leak to the guest if
> the populate completes.
>
> guest_memfd pages are zeroed at most once in the page's entire lifetime
> with guest_memfd, and that is tracked using the uptodate flag.
>
> Zeroing the page in __kvm_gmem_get_pfn() is chosen over zeroing in
> kvm_gmem_get_folio() since other flows, such as a future write() syscall,
> can get a page, write to the page and then set page uptodate without
> zeroing.
>
> This aligns with the concept of zeroing before first use - the other place
> where zeroing happens is in kvm_gmem_fault_user_mapping().
>
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Cheers,
/fuad
> ---
> virt/kvm/guest_memfd.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
> index 90bc1a26512b6..86c9f5b0863cb 100644
> --- a/virt/kvm/guest_memfd.c
> +++ b/virt/kvm/guest_memfd.c
> @@ -1137,6 +1137,11 @@ static struct folio *__kvm_gmem_get_pfn(struct file *file,
> return ERR_PTR(-EHWPOISON);
> }
>
> + if (!folio_test_uptodate(folio)) {
> + clear_highpage(folio_page(folio, 0));
> + folio_mark_uptodate(folio);
> + }
> +
> *pfn = folio_file_pfn(folio, index);
> if (max_order)
> *max_order = 0;
> @@ -1166,11 +1171,6 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
> goto out;
> }
>
> - if (!folio_test_uptodate(folio)) {
> - clear_highpage(folio_page(folio, 0));
> - folio_mark_uptodate(folio);
> - }
> -
> if (kvm_gmem_is_private_mem(inode, index))
> r = kvm_gmem_prepare_folio(kvm, slot, gfn, folio);
>
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v8 19/46] KVM: guest_memfd: Use actual size for invalidation in kvm_gmem_release()
From: Fuad Tabba @ 2026-06-19 10:46 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-19-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:31, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Ackerley Tng <ackerleytng@google.com>
>
> __kvm_gmem_invalidate_begin() and __kvm_gmem_invalidate_end() actually do
> not specially handle -1ul. -1ul is used as a huge number, which legal
> indices do not exceed, and hence the invalidation works as expected.
>
> Since a later patch is going to make use of the exact range, calculate the
> size of the guest_memfd inode and use it as the end range for invalidating
> SPTEs.
>
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
> ---
Reviewed-by: Fuad Tabba <tabba@google.com>
Cheers,
/fuad
> virt/kvm/guest_memfd.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
> index d163559da0235..d72ecbfcc3144 100644
> --- a/virt/kvm/guest_memfd.c
> +++ b/virt/kvm/guest_memfd.c
> @@ -366,6 +366,7 @@ static long kvm_gmem_fallocate(struct file *file, int mode, loff_t offset,
>
> static int kvm_gmem_release(struct inode *inode, struct file *file)
> {
> + pgoff_t end = i_size_read(inode) >> PAGE_SHIFT;
> struct gmem_file *f = file->private_data;
> struct kvm_memory_slot *slot;
> struct kvm *kvm = f->kvm;
> @@ -396,9 +397,9 @@ static int kvm_gmem_release(struct inode *inode, struct file *file)
> * Zap all SPTEs pointed at by this file. Do not free the backing
> * memory, as its lifetime is associated with the inode, not the file.
> */
> - __kvm_gmem_invalidate_start(f, 0, -1ul,
> + __kvm_gmem_invalidate_start(f, 0, end,
> kvm_gmem_get_invalidate_filter(inode));
> - __kvm_gmem_invalidate_end(f, 0, -1ul);
> + __kvm_gmem_invalidate_end(f, 0, end);
>
> list_del(&f->entry);
>
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v8 17/46] KVM: guest_memfd: Advertise KVM_SET_MEMORY_ATTRIBUTES2 ioctl
From: Fuad Tabba @ 2026-06-19 10:35 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-17-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:31, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Ackerley Tng <ackerleytng@google.com>
>
> Introduce KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES to advertise the
> availability of the KVM_SET_MEMORY_ATTRIBUTES2 ioctl.
>
> KVM_SET_MEMORY_ATTRIBUTES2 is a guest_memfd-scoped version of the existing
> KVM_SET_MEMORY_ATTRIBUTES VM ioctl. It allows userspace to manage memory
> attributes, such as KVM_MEMORY_ATTRIBUTE_PRIVATE, directly on a guest_memfd
> file descriptor.
>
> This new version uses struct kvm_memory_attributes2, which adds an
> error_offset field to the output. This allows KVM to return the specific
> offset that triggered an error, which is especially useful for handling
> EAGAIN results caused by transient page reference counts during attribute
> conversions.
>
> Update the KVM API documentation to define the new ioctl and its behavior,
> and add the necessary UAPI definitions and capability checks.
>
> Suggested-by: Sean Christopherson <seanjc@google.com>
> Suggested-by: Michael Roth <michael.roth@amd.com>
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Cheers,
/fuad
> ---
> Documentation/virt/kvm/api.rst | 78 +++++++++++++++++++++++++++++++++++++++++-
> include/uapi/linux/kvm.h | 2 ++
> virt/kvm/kvm_main.c | 23 +++++++++----
> 3 files changed, 95 insertions(+), 8 deletions(-)
>
> diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
> index a833d90845b95..73878f34f6d2e 100644
> --- a/Documentation/virt/kvm/api.rst
> +++ b/Documentation/virt/kvm/api.rst
> @@ -117,7 +117,7 @@ description:
> x86 includes both i386 and x86_64.
>
> Type:
> - system, vm, or vcpu.
> + system, vm, vcpu or guest_memfd.
>
> Parameters:
> what parameters are accepted by the ioctl.
> @@ -6373,6 +6373,8 @@ S390:
> Returns -EINVAL if the VM has the KVM_VM_S390_UCONTROL flag set.
> Returns -EINVAL if called on a protected VM.
>
> +.. _KVM_SET_MEMORY_ATTRIBUTES:
> +
> 4.141 KVM_SET_MEMORY_ATTRIBUTES
> -------------------------------
>
> @@ -6566,6 +6568,80 @@ KVM_S390_KEYOP_SSKE
> Sets the storage key for the guest address ``guest_addr`` to the key
> specified in ``key``, returning the previous value in ``key``.
>
> +4.145 KVM_SET_MEMORY_ATTRIBUTES2
> +---------------------------------
> +
> +:Capability: KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES
> +:Architectures: all
> +:Type: guest_memfd ioctl
> +:Parameters: struct kvm_memory_attributes2 (in/out)
> +:Returns: 0 on success, <0 on error
> +
> +Errors:
> +
> + ========== ===============================================================
> + EINVAL The specified `offset` or `size` were invalid (e.g. not
> + page aligned, causes an overflow, or size is zero).
> + EFAULT The parameter address was invalid.
> + EAGAIN Some page within requested range had unexpected refcounts. The
> + offset of the page will be returned in `error_offset`.
> + ENOMEM Ran out of memory trying to track private/shared state
> + ========== ===============================================================
> +
> +KVM_SET_MEMORY_ATTRIBUTES2 is an extension to
> +KVM_SET_MEMORY_ATTRIBUTES that supports returning (writing) values to
> +userspace. The original (pre-extension) fields are shared with
> +KVM_SET_MEMORY_ATTRIBUTES identically.
> +
> +Attribute values are shared with KVM_SET_MEMORY_ATTRIBUTES.
> +
> +::
> +
> + struct kvm_memory_attributes2 {
> + /* in */
> + union {
> + __u64 address;
> + __u64 offset;
> + };
> + __u64 size;
> + __u64 attributes;
> + __u64 flags;
> + /* out */
> + __u64 error_offset;
> + __u64 reserved[11];
> + };
> +
> + #define KVM_MEMORY_ATTRIBUTE_PRIVATE (1ULL << 3)
> +
> +Set attributes for a range of offsets within a guest_memfd to
> +KVM_MEMORY_ATTRIBUTE_PRIVATE to limit the specified guest_memfd backed
> +memory range for guest_use. Even if KVM_CAP_GUEST_MEMFD_MMAP is
> +supported, after a successful call to set
> +KVM_MEMORY_ATTRIBUTE_PRIVATE, the requested range will not be mappable
> +into host userspace and will only be mappable by the guest.
> +
> +To allow the range to be mappable into host userspace again, call
> +KVM_SET_MEMORY_ATTRIBUTES2 on the guest_memfd again with
> +KVM_MEMORY_ATTRIBUTE_PRIVATE unset.
> +
> +KVM does not directly manipulate the memory contents of pages during
> +attribute updates. However, the process of setting these attributes,
> +which includes operations such as unmapping pages from the host or
> +stage-2 page tables, may result in side effects on memory contents
> +that vary across different trusted firmware implementations.
> +
> +If this ioctl returns -EAGAIN, the offset of the page with unexpected
> +refcounts will be returned in `error_offset`. This can occur if there
> +are transient refcounts on the pages, taken by other parts of the
> +kernel.
> +
> +Userspace is expected to figure out how to remove all known refcounts
> +on the shared pages, such as refcounts taken by get_user_pages(), and
> +try the ioctl again. A possible source of these long term refcounts is
> +if the guest_memfd memory was pinned in IOMMU page tables.
> +
> +See also: :ref: `KVM_SET_MEMORY_ATTRIBUTES`.
> +
> .. _kvm_run:
>
> 5. The kvm_run structure
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index 876c0429f9d4e..129d6f6303251 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -997,6 +997,7 @@ struct kvm_enable_cap {
> #define KVM_CAP_S390_KEYOP 247
> #define KVM_CAP_S390_VSIE_ESAMODE 248
> #define KVM_CAP_S390_HPAGE_2G 249
> +#define KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES 250
>
> struct kvm_irq_routing_irqchip {
> __u32 irqchip;
> @@ -1649,6 +1650,7 @@ struct kvm_memory_attributes {
> __u64 flags;
> };
>
> +/* Available with KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES */
> #define KVM_SET_MEMORY_ATTRIBUTES2 _IOWR(KVMIO, 0xd2, struct kvm_memory_attributes2)
>
> struct kvm_memory_attributes2 {
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index a08b518cdb175..044486f128c37 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -2434,18 +2434,22 @@ static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm,
> }
> #endif /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */
>
> +#ifdef kvm_arch_has_private_mem
> +static u64 kvm_supports_private_mem(struct kvm *kvm)
> +{
> + return !kvm || kvm_arch_has_private_mem(kvm);
> +}
> +#else
> +#define kvm_supports_private_mem(kvm) false
> +#endif
> +
> #ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
> static u64 kvm_supported_vm_mem_attributes(struct kvm *kvm)
> {
> -#ifdef kvm_arch_has_private_mem
> - if (gmem_in_place_conversion)
> + if (gmem_in_place_conversion || !kvm_supports_private_mem(kvm))
> return 0;
>
> - if (!kvm || kvm_arch_has_private_mem(kvm))
> - return KVM_MEMORY_ATTRIBUTE_PRIVATE;
> -#endif
> -
> - return 0;
> + return KVM_MEMORY_ATTRIBUTE_PRIVATE;
> }
>
> /*
> @@ -4969,6 +4973,11 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
> return 1;
> case KVM_CAP_GUEST_MEMFD_FLAGS:
> return kvm_gmem_get_supported_flags(kvm);
> + case KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES:
> + if (!gmem_in_place_conversion || !kvm_supports_private_mem(kvm))
> + return 0;
> +
> + return KVM_MEMORY_ATTRIBUTE_PRIVATE;
> #endif
> default:
> break;
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v8 15/46] KVM: guest_memfd: Call arch invalidate hooks on conversion
From: Fuad Tabba @ 2026-06-19 10:09 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-15-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:31, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Ackerley Tng <ackerleytng@google.com>
>
> When memory in guest_memfd is converted from private to shared, the
> platform-specific state associated with the guest-private pages must be
> invalidated or cleaned up.
>
> Iterate over the folios in the affected range and call the
> kvm_arch_gmem_invalidate() hook for each PFN range. This allows
> architectures to perform necessary teardown, such as updating hardware
> metadata or encryption states, before the pages are transitioned to the
> shared state.
>
> Invoke this helper after indicating to KVM's mmu code that an invalidation
> is in progress to stop in-flight page faults from succeeding.
>
> Reviewed-by: Fuad Tabba <tabba@google.com>
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
Coming back to this after working through the arm64/pKVM side. My
Reviewed-by here is from the previous round and the patch hasn't
changed, but I missed an implication for arm64.
kvm_arch_gmem_invalidate() is now called from two paths with the same
(start, end) signature: folio teardown (kvm_gmem_free_folio) and
private->shared conversion (here). For SNP/TDX that's fine, conversion is
destructive anyway. For pKVM the two need opposite content semantics:
conversion must preserve the page in place (same physical page, the point
of in-place conversion without encryption), while teardown must scrub it
before returning it to the host.
The hook gets only a pfn range with no indication of which caller it's
serving, so arm64 can't give the two paths the behaviour they need. It
would help to signal intent on the conversion path: a reason/flag, a
separate hook, or not routing non-destructive conversion through the
teardown hook.
arm64 isn't here yet, so this isn't urgent, but the hook is gaining a
second caller now, and it's cheaper to leave room for the distinction
than to change a generic contract other arches depend on later.
Cheers,
/fuad
> ---
> virt/kvm/guest_memfd.c | 41 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 41 insertions(+)
>
> diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
> index 433f79047b9d1..3c94442bc8131 100644
> --- a/virt/kvm/guest_memfd.c
> +++ b/virt/kvm/guest_memfd.c
> @@ -607,6 +607,42 @@ static bool kvm_gmem_is_safe_for_conversion(struct inode *inode, pgoff_t start,
> return safe;
> }
>
> +#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_INVALIDATE
> +static void kvm_gmem_invalidate(struct inode *inode, pgoff_t start, pgoff_t end)
> +{
> + struct folio_batch fbatch;
> + pgoff_t next = start;
> + int i;
> +
> + folio_batch_init(&fbatch);
> + while (filemap_get_folios(inode->i_mapping, &next, end - 1, &fbatch)) {
> + for (i = 0; i < folio_batch_count(&fbatch); ++i) {
> + struct folio *folio = fbatch.folios[i];
> + pgoff_t start_index, end_index;
> + kvm_pfn_t start_pfn, end_pfn;
> +
> + start_index = max(start, folio->index);
> + end_index = min(end, folio_next_index(folio));
> + /*
> + * end_index is either in folio or points to
> + * the first page of the next folio. Hence,
> + * all pages in range [start_index, end_index)
> + * are contiguous.
> + */
> + start_pfn = folio_file_pfn(folio, start_index);
> + end_pfn = start_pfn + end_index - start_index;
> +
> + kvm_arch_gmem_invalidate(start_pfn, end_pfn);
> + }
> +
> + folio_batch_release(&fbatch);
> + cond_resched();
> + }
> +}
> +#else
> +static void kvm_gmem_invalidate(struct inode *inode, pgoff_t start, pgoff_t end) {}
> +#endif
> +
> static int __kvm_gmem_set_attributes(struct inode *inode, pgoff_t start,
> size_t nr_pages, uint64_t attrs,
> pgoff_t *err_index)
> @@ -647,7 +683,12 @@ static int __kvm_gmem_set_attributes(struct inode *inode, pgoff_t start,
> */
>
> kvm_gmem_invalidate_start(inode, start, end);
> +
> + if (!to_private)
> + kvm_gmem_invalidate(inode, start, end);
> +
> mas_store_prealloc(&mas, xa_mk_value(attrs));
> +
> kvm_gmem_invalidate_end(inode, start, end);
> out:
> filemap_invalidate_unlock(mapping);
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v8 08/46] KVM: Provide generic interface for checking memory private/shared status
From: Suzuki K Poulose @ 2026-06-19 9:57 UTC (permalink / raw)
To: Fuad Tabba, ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, aneesh.kumar, liam, Paolo Bonzini,
Sean Christopherson, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, Dave Hansen, x86, H. Peter Anvin, Steven Rostedt,
Masami Hiramatsu, Mathieu Desnoyers, Jonathan Corbet, Shuah Khan,
Shuah Khan, Vishal Annapurve, Andrew Morton, Chris Li,
Kairui Song, Kemeng Shi, Nhat Pham, Barry Song, Axel Rasmussen,
Yuanchu Xie, Wei Xu, Youngjun Park, Qi Zheng, Shakeel Butt,
Kiryl Shutsemau, Baoquan He, Jason Gunthorpe, Vlastimil Babka,
kvm, linux-kernel, linux-trace-kernel, linux-doc, linux-kselftest,
linux-mm, linux-coco
In-Reply-To: <CA+EHjTxu32nQ+vPV7Zmcw76_-V4g2_g=P_UzRnnO2dP1PFO2ww@mail.gmail.com>
On 19/06/2026 09:21, Fuad Tabba wrote:
> On Fri, 19 Jun 2026 at 09:19, Fuad Tabba <tabba@google.com> wrote:
>>
>> On Fri, 19 Jun 2026 at 01:31, Ackerley Tng via B4 Relay
>> <devnull+ackerleytng.google.com@kernel.org> wrote:
>>>
>>> From: Sean Christopherson <seanjc@google.com>
>>>
>>> Introduce a generic kvm_mem_is_private() interface using a static call to
>>> determine if a GFN is private. This allows the implementation for checking
>>> a GFN's private/shared status to be set at runtime.
>>>
>>> In preparation for choosing implementations between a guest_memfd lookup
>>> and the existing VM attribute lookup, rename the existing
>>> VM-attribute-based check to kvm_vm_mem_is_private to emphasize that it
>>> looks up VM attributes.
>>>
>>> Signed-off-by: Sean Christopherson <seanjc@google.com>
>>
>> (SoB fix plz)
>>
>> Reviewed-by: Fuad Tabba <tabba@google.com>
>>
>> Cheers,
>> /fuad
>>> ---
>>> include/linux/kvm_host.h | 12 +++++++++++-
>>> virt/kvm/kvm_main.c | 15 +++++++++++++++
>>> 2 files changed, 26 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
>>> index eb26d4ea8945a..3915da2a61778 100644
>>> --- a/include/linux/kvm_host.h
>>> +++ b/include/linux/kvm_host.h
>>> @@ -2546,7 +2546,7 @@ bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm,
>>> bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,
>>> struct kvm_gfn_range *range);
>>>
>>> -static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
>>> +static inline bool kvm_vm_mem_is_private(struct kvm *kvm, gfn_t gfn)
>
> Should have read the Sashiko review first, but where is this used?
> It's not used at all in this series...
See below:
>
> /fuad
>
>>> {
>>> return kvm_get_vm_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE;
>>> }
>>> @@ -2557,6 +2557,16 @@ static inline bool kvm_mem_range_is_private(struct kvm *kvm, gfn_t start,
>>> KVM_MEMORY_ATTRIBUTE_PRIVATE,
>>> KVM_MEMORY_ATTRIBUTE_PRIVATE);
>>> }
>>> +#endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
>>> +
>>> +#ifdef kvm_arch_has_private_mem
>>> +typedef bool (kvm_mem_is_private_t)(struct kvm *kvm, gfn_t gfn);
>>> +DECLARE_STATIC_CALL(__kvm_mem_is_private, kvm_mem_is_private_t);
>>> +
>>> +static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
>>> +{
>>> + return static_call(__kvm_mem_is_private)(kvm, gfn);
>>> +}
>>> #else
>>> static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
>>> {
>>> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
>>> index 6669f1477013c..8b238e461b854 100644
>>> --- a/virt/kvm/kvm_main.c
>>> +++ b/virt/kvm/kvm_main.c
>>> @@ -2627,6 +2627,20 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
>>> }
>>> #endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
>>>
>>> +#ifdef kvm_arch_has_private_mem
>>> +DEFINE_STATIC_CALL_RET0(__kvm_mem_is_private, kvm_mem_is_private_t);
>>> +EXPORT_STATIC_CALL_GPL(__kvm_mem_is_private);
>>> +
>>> +static void kvm_init_memory_attributes(void)
>>> +{
>>> +#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
>>> + static_call_update(__kvm_mem_is_private, kvm_vm_mem_is_private);
>>> +#endif
>>> +}
Here ^^ as the static call update ?
Suzuki
^ permalink raw reply
* Re: [PATCH v8 13/46] KVM: guest_memfd: Add base support for KVM_SET_MEMORY_ATTRIBUTES2
From: Fuad Tabba @ 2026-06-19 9:25 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-13-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:31, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Ackerley Tng <ackerleytng@google.com>
>
> Introduce base support for KVM_SET_MEMORY_ATTRIBUTES2 in guest_memfd, which
> just updates attributes tracked by guest_memfd.
>
> Validate input fields in general. Guard usage of KVM_SET_MEMORY_ATTRIBUTES2
> by making sure requested attributes are supported for this instance of kvm.
>
> A new KVM_SET_MEMORY_ATTRIBUTES2 is defined to support writes (unlike
> KVM_SET_MEMORY_ATTRIBUTES) in addition to reads so it can provide error
> details to userspace. This will be used in a later patch.
>
> The two ioctls use their corresponding structs with no overlap, but
> backward compatibility is baked in for future support of
> KVM_SET_MEMORY_ATTRIBUTES2 and struct kvm_memory_attributes2 in the VM
> ioctl.
>
> The process of setting memory attributes is set up such that the later half
> will not fail due to allocation. Any necessary checks are performed before
> the point of no return.
>
> Co-developed-by: Vishal Annapurve <vannapurve@google.com>
> Signed-off-by: Vishal Annapurve <vannapurve@google.com>
> Co-developed-by: Sean Christoperson <seanjc@google.com>
> Signed-off-by: Sean Christoperson <seanjc@google.com>
> Reviewed-by: Fuad Tabba <tabba@google.com>
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
Note sure if it's user error on my part, if I'm applying this to the
wrong base, but I found a build break here on patch 13:
kvm_gmem_invalidate_start() doesn't exist in the base tree. The
function is kvm_gmem_invalidate_begin() here. The rename
(190cc5370a8b6) landed via a different merge path and isn't an
ancestor of the stated base.
Patches 19 and 20 have the same mismatch. Fix for all three is
s/kvm_gmem_invalidate_start/kvm_gmem_invalidate_begin/.
Cheers,
/fuad
> ---
> include/uapi/linux/kvm.h | 13 ++++++
> virt/kvm/Kconfig | 1 +
> virt/kvm/guest_memfd.c | 116 +++++++++++++++++++++++++++++++++++++++++++++++
> virt/kvm/kvm_main.c | 12 +++++
> 4 files changed, 142 insertions(+)
>
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index 419011097fa8e..956877a6aab05 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -1649,6 +1649,19 @@ struct kvm_memory_attributes {
> __u64 flags;
> };
>
> +#define KVM_SET_MEMORY_ATTRIBUTES2 _IOWR(KVMIO, 0xd2, struct kvm_memory_attributes2)
> +
> +struct kvm_memory_attributes2 {
> + union {
> + __u64 address;
> + __u64 offset;
> + };
> + __u64 size;
> + __u64 attributes;
> + __u64 flags;
> + __u64 reserved[12];
> +};
> +
> #define KVM_MEMORY_ATTRIBUTE_PRIVATE (1ULL << 3)
>
> #define KVM_CREATE_GUEST_MEMFD _IOWR(KVMIO, 0xd4, struct kvm_create_guest_memfd)
> diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
> index 297e4399fbd49..cfa2c78ba5fb9 100644
> --- a/virt/kvm/Kconfig
> +++ b/virt/kvm/Kconfig
> @@ -102,6 +102,7 @@ config KVM_MMU_LOCKLESS_AGING
>
> config KVM_GUEST_MEMFD
> select XARRAY_MULTI
> + select KVM_MEMORY_ATTRIBUTES
> bool
>
> config HAVE_KVM_ARCH_GMEM_PREPARE
> diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
> index 65ce795c090d9..0d14548c1ed22 100644
> --- a/virt/kvm/guest_memfd.c
> +++ b/virt/kvm/guest_memfd.c
> @@ -541,11 +541,127 @@ bool kvm_gmem_is_private(struct kvm *kvm, gfn_t gfn)
> }
> EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_gmem_is_private);
>
> +/*
> + * Preallocate memory for attributes to be stored on a maple tree, pointed to
> + * by mas. Adjacent ranges with attributes identical to the new attributes
> + * will be merged. Also sets mas's bounds up for storing attributes.
> + *
> + * This maintains the invariant that ranges with the same attributes will
> + * always be merged.
> + */
> +static int kvm_gmem_mas_preallocate(struct ma_state *mas, u64 attributes,
> + pgoff_t start, size_t nr_pages)
> +{
> + pgoff_t end = start + nr_pages;
> + pgoff_t last = end - 1;
> + void *entry;
> +
> + /* Try extending range. entry is NULL on overflow/wrap-around. */
> + mas_set(mas, end);
> + entry = mas_find(mas, end);
> + if (entry && xa_to_value(entry) == attributes)
> + last = mas->last;
> +
> + if (start > 0) {
> + mas_set(mas, start - 1);
> + entry = mas_find(mas, start - 1);
> + if (entry && xa_to_value(entry) == attributes)
> + start = mas->index;
> + }
> +
> + mas_set_range(mas, start, last);
> + return mas_preallocate(mas, xa_mk_value(attributes), GFP_KERNEL);
> +}
> +
> +static int __kvm_gmem_set_attributes(struct inode *inode, pgoff_t start,
> + size_t nr_pages, uint64_t attrs)
> +{
> + struct address_space *mapping = inode->i_mapping;
> + struct gmem_inode *gi = GMEM_I(inode);
> + pgoff_t end = start + nr_pages;
> + struct maple_tree *mt;
> + struct ma_state mas;
> + int r;
> +
> + mt = &gi->attributes;
> +
> + filemap_invalidate_lock(mapping);
> +
> + mas_init(&mas, mt, start);
> + r = kvm_gmem_mas_preallocate(&mas, attrs, start, nr_pages);
> + if (r)
> + goto out;
> +
> + /*
> + * From this point on guest_memfd has performed necessary
> + * checks and can proceed to do guest-breaking changes.
> + */
> +
> + kvm_gmem_invalidate_start(inode, start, end);
> + mas_store_prealloc(&mas, xa_mk_value(attrs));
> + kvm_gmem_invalidate_end(inode, start, end);
> +out:
> + filemap_invalidate_unlock(mapping);
> + return r;
> +}
> +
> +static long kvm_gmem_set_attributes(struct file *file, void __user *argp)
> +{
> + struct gmem_file *f = file->private_data;
> + struct inode *inode = file_inode(file);
> + struct kvm_memory_attributes2 attrs;
> + size_t nr_pages;
> + pgoff_t index;
> + int i;
> +
> + if (copy_from_user(&attrs, argp, sizeof(attrs)))
> + return -EFAULT;
> +
> + if (attrs.flags)
> + return -EINVAL;
> + for (i = 0; i < ARRAY_SIZE(attrs.reserved); i++) {
> + if (attrs.reserved[i])
> + return -EINVAL;
> + }
> + if (!kvm_arch_has_private_mem(f->kvm))
> + return -EINVAL;
> + if (attrs.attributes & ~KVM_MEMORY_ATTRIBUTE_PRIVATE)
> + return -EINVAL;
> + if (attrs.size == 0 || attrs.offset + attrs.size < attrs.offset)
> + return -EINVAL;
> + if (!PAGE_ALIGNED(attrs.offset) || !PAGE_ALIGNED(attrs.size))
> + return -EINVAL;
> +
> + if (attrs.offset >= i_size_read(inode) ||
> + attrs.offset + attrs.size > i_size_read(inode))
> + return -EINVAL;
> +
> + nr_pages = attrs.size >> PAGE_SHIFT;
> + index = attrs.offset >> PAGE_SHIFT;
> + return __kvm_gmem_set_attributes(inode, index, nr_pages,
> + attrs.attributes);
> +}
> +
> +static long kvm_gmem_ioctl(struct file *file, unsigned int ioctl,
> + unsigned long arg)
> +{
> + switch (ioctl) {
> + case KVM_SET_MEMORY_ATTRIBUTES2:
> + if (!gmem_in_place_conversion)
> + return -ENOTTY;
> +
> + return kvm_gmem_set_attributes(file, (void __user *)arg);
> + default:
> + return -ENOTTY;
> + }
> +}
> +
> static struct file_operations kvm_gmem_fops = {
> .mmap = kvm_gmem_mmap,
> .open = generic_file_open,
> .release = kvm_gmem_release,
> .fallocate = kvm_gmem_fallocate,
> + .unlocked_ioctl = kvm_gmem_ioctl,
> };
>
> static int kvm_gmem_migrate_folio(struct address_space *mapping,
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 01761f6e25d25..a08b518cdb175 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -105,6 +105,18 @@ module_param(allow_unsafe_mappings, bool, 0444);
> bool __ro_after_init gmem_in_place_conversion = false;
> #endif
>
> +#define MEMORY_ATTRIBUTES_MATCH(one, two) \
> + static_assert(offsetof(struct kvm_memory_attributes, one) == \
> + offsetof(struct kvm_memory_attributes2, two)); \
> + static_assert(sizeof_field(struct kvm_memory_attributes, one) ==\
> + sizeof_field(struct kvm_memory_attributes2, two))
> +
> +/* Ensure the common parts of the two structs are identical. */
> +MEMORY_ATTRIBUTES_MATCH(address, address);
> +MEMORY_ATTRIBUTES_MATCH(size, size);
> +MEMORY_ATTRIBUTES_MATCH(attributes, attributes);
> +MEMORY_ATTRIBUTES_MATCH(flags, flags);
> +
> /*
> * Ordering of locks:
> *
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH] rv: update rvgen monitor synthesis documentation path
From: Gabriele Monaco @ 2026-06-19 8:52 UTC (permalink / raw)
To: lucayu.alight; +Cc: linux-trace-kernel, linux-kernel, Steven Rostedt
In-Reply-To: <20260618-rvgen-doc-path-v1-1-9bcf0148417a@gmail.com>
On Thu, 2026-06-18 at 21:45 +0800, Yu Chuanyu via B4 Relay wrote:
> From: Yu Chuanyu <lucayu.alight@gmail.com>
>
> The rvgen source comments still refer to da_monitor_synthesis.rst,
> which
> no longer exists. The documentation is now available in
> monitor_synthesis.rst. Update both references to point to the current
> file.
>
> Signed-off-by: Yu Chuanyu <lucayu.alight@gmail.com>
Thanks for catching this!
Acked-by: Gabriele Monaco <gmonaco@redhat.com>
> ---
> tools/verification/rvgen/__main__.py | 2 +-
> tools/verification/rvgen/rvgen/dot2k.py | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tools/verification/rvgen/__main__.py
> b/tools/verification/rvgen/__main__.py
> index 5c923dc..2a2bb03 100644
> --- a/tools/verification/rvgen/__main__.py
> +++ b/tools/verification/rvgen/__main__.py
> @@ -6,7 +6,7 @@
> # dot2k: transform dot files into a monitor for the Linux kernel.
> #
> # For further information, see:
> -# Documentation/trace/rv/da_monitor_synthesis.rst
> +# Documentation/trace/rv/monitor_synthesis.rst
>
> if __name__ == '__main__':
> from rvgen.dot2k import da2k, ha2k
> diff --git a/tools/verification/rvgen/rvgen/dot2k.py
> b/tools/verification/rvgen/rvgen/dot2k.py
> index 110cfd6..326984f 100644
> --- a/tools/verification/rvgen/rvgen/dot2k.py
> +++ b/tools/verification/rvgen/rvgen/dot2k.py
> @@ -6,7 +6,7 @@
> # dot2k: transform dot files into a monitor for the Linux kernel.
> #
> # For further information, see:
> -# Documentation/trace/rv/da_monitor_synthesis.rst
> +# Documentation/trace/rv/monitor_synthesis.rst
>
> from collections import deque
> from .dot2c import Dot2c
>
> ---
> base-commit: e771677c937da5808f7b6c1f0e4a97ec1a84f8a8
> change-id: 20260618-rvgen-doc-path-11695c57153d
>
> Best regards,
> --
> Yu Chuanyu <lucayu.alight@gmail.com>
>
>
^ permalink raw reply
* Re: [PATCH v8 10/46] KVM: guest_memfd: Wire up core private/shared attribute interfaces
From: Fuad Tabba @ 2026-06-19 8:34 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-10-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:31, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Sean Christopherson <seanjc@google.com>
>
> With in-place conversion, guest_memfd is able to track the private/shared
> status of memory. Use a global flag to toggle between tracking
> private/shared status per-vm or within guest_memfd.
>
> When queried for supported vm memory attributes, return 0 if attributes are
> tracked in guest_memfd.
>
> When querying for memory attributes over a range, look up memory attributes
> based on the flag's state at query time.
>
> For per-GFN memory attribute queries, choosing an implementation (VM or
> guest_memfd lookup) at KVM load time.
>
> The flag is always false for now and will be made toggle-able after all
> in-place conversion features are added in subsequent patches.
>
> If/since the flag is false, if CONFIG_KVM_VM_MEMORY_ATTRIBUTES is also not
> selected, the per-GFN memory attribute query defaults to returning
> 0 (false/not private).
>
> Co-developed-by: Ackerley Tng <ackerleytng@google.com>
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Cheers,
/fuad
> ---
> include/linux/kvm_host.h | 4 ++++
> virt/kvm/guest_memfd.c | 22 +++++++++++++++++++---
> virt/kvm/kvm_main.c | 12 +++++++++++-
> 3 files changed, 34 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 27687fb9d5201..acb552745b428 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -2560,6 +2560,8 @@ static inline bool kvm_mem_range_is_private(struct kvm *kvm, gfn_t start,
> #endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
>
> #ifdef kvm_arch_has_private_mem
> +extern bool gmem_in_place_conversion;
> +
> typedef bool (kvm_mem_is_private_t)(struct kvm *kvm, gfn_t gfn);
> DECLARE_STATIC_CALL(__kvm_mem_is_private, kvm_mem_is_private_t);
>
> @@ -2568,6 +2570,8 @@ static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
> return static_call(__kvm_mem_is_private)(kvm, gfn);
> }
> #else
> +#define gmem_in_place_conversion false
> +
> static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
> {
> return false;
> diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
> index bca912db5be6e..e0e544ef47d69 100644
> --- a/virt/kvm/guest_memfd.c
> +++ b/virt/kvm/guest_memfd.c
> @@ -926,6 +926,24 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
> EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_gmem_get_pfn);
>
> #ifdef CONFIG_HAVE_KVM_ARCH_GMEM_POPULATE
> +static bool kvm_gmem_range_is_private(struct file *file, pgoff_t index,
> + size_t nr_pages, struct kvm *kvm, gfn_t gfn)
> +{
> + struct maple_tree *mt = &GMEM_I(file_inode(file))->attributes;
> + pgoff_t end = index + nr_pages - 1;
> + void *entry;
> +
> + if (!gmem_in_place_conversion)
> + return kvm_range_has_vm_memory_attributes(kvm, gfn, gfn + nr_pages,
> + KVM_MEMORY_ATTRIBUTE_PRIVATE,
> + KVM_MEMORY_ATTRIBUTE_PRIVATE);
> +
> + mt_for_each(mt, entry, index, end) {
> + if (xa_to_value(entry) != KVM_MEMORY_ATTRIBUTE_PRIVATE)
> + return false;
> + }
> + return true;
> +}
>
> static long __kvm_gmem_populate(struct kvm *kvm, struct kvm_memory_slot *slot,
> struct file *file, gfn_t gfn, struct page *src_page,
> @@ -946,9 +964,7 @@ static long __kvm_gmem_populate(struct kvm *kvm, struct kvm_memory_slot *slot,
>
> folio_unlock(folio);
>
> - if (!kvm_range_has_vm_memory_attributes(kvm, gfn, gfn + 1,
> - KVM_MEMORY_ATTRIBUTE_PRIVATE,
> - KVM_MEMORY_ATTRIBUTE_PRIVATE)) {
> + if (!kvm_gmem_range_is_private(file, index, 1, kvm, gfn)) {
> ret = -EINVAL;
> goto out_put_folio;
> }
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 8b238e461b854..01761f6e25d25 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -101,6 +101,10 @@ EXPORT_SYMBOL_FOR_KVM_INTERNAL(halt_poll_ns_shrink);
> static bool __ro_after_init allow_unsafe_mappings;
> module_param(allow_unsafe_mappings, bool, 0444);
>
> +#ifdef kvm_arch_has_private_mem
> +bool __ro_after_init gmem_in_place_conversion = false;
> +#endif
> +
> /*
> * Ordering of locks:
> *
> @@ -2422,6 +2426,9 @@ static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm,
> static u64 kvm_supported_vm_mem_attributes(struct kvm *kvm)
> {
> #ifdef kvm_arch_has_private_mem
> + if (gmem_in_place_conversion)
> + return 0;
> +
> if (!kvm || kvm_arch_has_private_mem(kvm))
> return KVM_MEMORY_ATTRIBUTE_PRIVATE;
> #endif
> @@ -2633,8 +2640,11 @@ EXPORT_STATIC_CALL_GPL(__kvm_mem_is_private);
>
> static void kvm_init_memory_attributes(void)
> {
> + if (gmem_in_place_conversion)
> + static_call_update(__kvm_mem_is_private, kvm_gmem_is_private);
> #ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
> - static_call_update(__kvm_mem_is_private, kvm_vm_mem_is_private);
> + else
> + static_call_update(__kvm_mem_is_private, kvm_vm_mem_is_private);
> #endif
> }
> #else
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v5 1/7] tracing/events: Fix to check the simple_tsk_fn creation
From: Masami Hiramatsu @ 2026-06-19 8:33 UTC (permalink / raw)
To: Masami Hiramatsu (Google)
Cc: Steven Rostedt, Mathieu Desnoyers, Jonathan Corbet, Shuah Khan,
linux-kernel, linux-trace-kernel, linux-doc, linux-kselftest
In-Reply-To: <178165817322.269421.3992299509400184196.stgit@devnote2>
Let me pick this fix to probes/core.
Thanks,
On Wed, 17 Jun 2026 10:02:53 +0900
"Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:
> From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
>
> Sashiko pointed that this sample code does not correctly handle the
> failure of thread creation because kthread_run() can return -errno.
>
> Check the simple_tsk_fn is correctly initialized (created) or not.
>
> Link: https://sashiko.dev/#/patchset/178092865666.163648.10457567771536160909.stgit%40devnote2
>
> Fixes: 9cfe06f8cd5c ("tracing/events: add trace-events-sample")
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> ---
> Changes in v4:
> - Fix to remove decrementing counter in error path, since foo_bar_reg() always returns 0.
> - Add a newline to error message.
> Changes in v3:
> - Recover the usage counter.
> ---
> samples/trace_events/trace-events-sample.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/samples/trace_events/trace-events-sample.c b/samples/trace_events/trace-events-sample.c
> index ecc7db237f2e..0b7a6efdb247 100644
> --- a/samples/trace_events/trace-events-sample.c
> +++ b/samples/trace_events/trace-events-sample.c
> @@ -107,6 +107,10 @@ int foo_bar_reg(void)
> * for consistency sake, we still take the thread_mutex.
> */
> simple_tsk_fn = kthread_run(simple_thread_fn, NULL, "event-sample-fn");
> + if (IS_ERR_OR_NULL(simple_tsk_fn)) {
> + pr_err("Failed to create simple_thread_fn\n");
> + simple_tsk_fn = NULL;
> + }
> out:
> mutex_unlock(&thread_mutex);
> return 0;
>
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply
* Re: [PATCH v8 09/46] KVM: guest_memfd: Introduce function to check GFN private/shared status
From: Fuad Tabba @ 2026-06-19 8:25 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-9-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:31, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Ackerley Tng <ackerleytng@google.com>
>
> Introduce function for KVM to check the private/shared status of guest
> memory at a given GFN.
>
> This will be used in a later patch.
>
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
> Co-developed-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Cheers,
/fuad
> ---
> include/linux/kvm_host.h | 2 ++
> virt/kvm/guest_memfd.c | 31 +++++++++++++++++++++++++++++++
> 2 files changed, 33 insertions(+)
>
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 3915da2a61778..27687fb9d5201 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -2575,6 +2575,8 @@ static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
> #endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
>
> #ifdef CONFIG_KVM_GUEST_MEMFD
> +bool kvm_gmem_is_private(struct kvm *kvm, gfn_t gfn);
> +
> int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
> gfn_t gfn, kvm_pfn_t *pfn, struct page **page,
> int *max_order);
> diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
> index 8101f64e0366f..bca912db5be6e 100644
> --- a/virt/kvm/guest_memfd.c
> +++ b/virt/kvm/guest_memfd.c
> @@ -510,6 +510,37 @@ static int kvm_gmem_mmap(struct file *file, struct vm_area_struct *vma)
> return 0;
> }
>
> +bool kvm_gmem_is_private(struct kvm *kvm, gfn_t gfn)
> +{
> + struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
> + struct inode *inode;
> +
> + /*
> + * If this gfn has no associated memslot, there's no chance of the gfn
> + * being backed by private memory, since guest_memfd must be used for
> + * private memory, and guest_memfd must be associated with some memslot.
> + */
> + if (!slot)
> + return 0;
> +
> + CLASS(gmem_get_file, file)(slot);
> + if (!file)
> + return 0;
> +
> + inode = file_inode(file);
> +
> + /*
> + * Rely on the maple tree's internal RCU lock to ensure a
> + * stable result. This result can become stale as soon as the
> + * lock is dropped, so the caller _must_ still protect
> + * consumption of private vs. shared by checking
> + * mmu_invalidate_retry_gfn() under mmu_lock to serialize
> + * against ongoing attribute updates.
> + */
> + return kvm_gmem_is_private_mem(inode, kvm_gmem_get_index(slot, gfn));
> +}
> +EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_gmem_is_private);
> +
> static struct file_operations kvm_gmem_fops = {
> .mmap = kvm_gmem_mmap,
> .open = generic_file_open,
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v8 08/46] KVM: Provide generic interface for checking memory private/shared status
From: Fuad Tabba @ 2026-06-19 8:21 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <CA+EHjTw6x-mxDnJjnhE-6SV73tMrb0paKDTtOC2j6zJ1fXZDLA@mail.gmail.com>
On Fri, 19 Jun 2026 at 09:19, Fuad Tabba <tabba@google.com> wrote:
>
> On Fri, 19 Jun 2026 at 01:31, Ackerley Tng via B4 Relay
> <devnull+ackerleytng.google.com@kernel.org> wrote:
> >
> > From: Sean Christopherson <seanjc@google.com>
> >
> > Introduce a generic kvm_mem_is_private() interface using a static call to
> > determine if a GFN is private. This allows the implementation for checking
> > a GFN's private/shared status to be set at runtime.
> >
> > In preparation for choosing implementations between a guest_memfd lookup
> > and the existing VM attribute lookup, rename the existing
> > VM-attribute-based check to kvm_vm_mem_is_private to emphasize that it
> > looks up VM attributes.
> >
> > Signed-off-by: Sean Christopherson <seanjc@google.com>
>
> (SoB fix plz)
>
> Reviewed-by: Fuad Tabba <tabba@google.com>
>
> Cheers,
> /fuad
> > ---
> > include/linux/kvm_host.h | 12 +++++++++++-
> > virt/kvm/kvm_main.c | 15 +++++++++++++++
> > 2 files changed, 26 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> > index eb26d4ea8945a..3915da2a61778 100644
> > --- a/include/linux/kvm_host.h
> > +++ b/include/linux/kvm_host.h
> > @@ -2546,7 +2546,7 @@ bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm,
> > bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,
> > struct kvm_gfn_range *range);
> >
> > -static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
> > +static inline bool kvm_vm_mem_is_private(struct kvm *kvm, gfn_t gfn)
Should have read the Sashiko review first, but where is this used?
It's not used at all in this series...
/fuad
> > {
> > return kvm_get_vm_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE;
> > }
> > @@ -2557,6 +2557,16 @@ static inline bool kvm_mem_range_is_private(struct kvm *kvm, gfn_t start,
> > KVM_MEMORY_ATTRIBUTE_PRIVATE,
> > KVM_MEMORY_ATTRIBUTE_PRIVATE);
> > }
> > +#endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
> > +
> > +#ifdef kvm_arch_has_private_mem
> > +typedef bool (kvm_mem_is_private_t)(struct kvm *kvm, gfn_t gfn);
> > +DECLARE_STATIC_CALL(__kvm_mem_is_private, kvm_mem_is_private_t);
> > +
> > +static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
> > +{
> > + return static_call(__kvm_mem_is_private)(kvm, gfn);
> > +}
> > #else
> > static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
> > {
> > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> > index 6669f1477013c..8b238e461b854 100644
> > --- a/virt/kvm/kvm_main.c
> > +++ b/virt/kvm/kvm_main.c
> > @@ -2627,6 +2627,20 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
> > }
> > #endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
> >
> > +#ifdef kvm_arch_has_private_mem
> > +DEFINE_STATIC_CALL_RET0(__kvm_mem_is_private, kvm_mem_is_private_t);
> > +EXPORT_STATIC_CALL_GPL(__kvm_mem_is_private);
> > +
> > +static void kvm_init_memory_attributes(void)
> > +{
> > +#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
> > + static_call_update(__kvm_mem_is_private, kvm_vm_mem_is_private);
> > +#endif
> > +}
> > +#else
> > +static void kvm_init_memory_attributes(void) { }
> > +#endif
> > +
> > struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
> > {
> > return __gfn_to_memslot(kvm_memslots(kvm), gfn);
> > @@ -6528,6 +6542,7 @@ int kvm_init(unsigned vcpu_size, unsigned vcpu_align, struct module *module)
> > kvm_preempt_ops.sched_in = kvm_sched_in;
> > kvm_preempt_ops.sched_out = kvm_sched_out;
> >
> > + kvm_init_memory_attributes();
> > kvm_init_debug();
> >
> > r = kvm_vfio_ops_init();
> >
> > --
> > 2.55.0.rc0.738.g0c8ab3ebcc-goog
> >
> >
^ permalink raw reply
* Re: [PATCH v8 08/46] KVM: Provide generic interface for checking memory private/shared status
From: Fuad Tabba @ 2026-06-19 8:19 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-8-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:31, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Sean Christopherson <seanjc@google.com>
>
> Introduce a generic kvm_mem_is_private() interface using a static call to
> determine if a GFN is private. This allows the implementation for checking
> a GFN's private/shared status to be set at runtime.
>
> In preparation for choosing implementations between a guest_memfd lookup
> and the existing VM attribute lookup, rename the existing
> VM-attribute-based check to kvm_vm_mem_is_private to emphasize that it
> looks up VM attributes.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
(SoB fix plz)
Reviewed-by: Fuad Tabba <tabba@google.com>
Cheers,
/fuad
> ---
> include/linux/kvm_host.h | 12 +++++++++++-
> virt/kvm/kvm_main.c | 15 +++++++++++++++
> 2 files changed, 26 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index eb26d4ea8945a..3915da2a61778 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -2546,7 +2546,7 @@ bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm,
> bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,
> struct kvm_gfn_range *range);
>
> -static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
> +static inline bool kvm_vm_mem_is_private(struct kvm *kvm, gfn_t gfn)
> {
> return kvm_get_vm_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE;
> }
> @@ -2557,6 +2557,16 @@ static inline bool kvm_mem_range_is_private(struct kvm *kvm, gfn_t start,
> KVM_MEMORY_ATTRIBUTE_PRIVATE,
> KVM_MEMORY_ATTRIBUTE_PRIVATE);
> }
> +#endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
> +
> +#ifdef kvm_arch_has_private_mem
> +typedef bool (kvm_mem_is_private_t)(struct kvm *kvm, gfn_t gfn);
> +DECLARE_STATIC_CALL(__kvm_mem_is_private, kvm_mem_is_private_t);
> +
> +static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
> +{
> + return static_call(__kvm_mem_is_private)(kvm, gfn);
> +}
> #else
> static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
> {
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 6669f1477013c..8b238e461b854 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -2627,6 +2627,20 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
> }
> #endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */
>
> +#ifdef kvm_arch_has_private_mem
> +DEFINE_STATIC_CALL_RET0(__kvm_mem_is_private, kvm_mem_is_private_t);
> +EXPORT_STATIC_CALL_GPL(__kvm_mem_is_private);
> +
> +static void kvm_init_memory_attributes(void)
> +{
> +#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
> + static_call_update(__kvm_mem_is_private, kvm_vm_mem_is_private);
> +#endif
> +}
> +#else
> +static void kvm_init_memory_attributes(void) { }
> +#endif
> +
> struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
> {
> return __gfn_to_memslot(kvm_memslots(kvm), gfn);
> @@ -6528,6 +6542,7 @@ int kvm_init(unsigned vcpu_size, unsigned vcpu_align, struct module *module)
> kvm_preempt_ops.sched_in = kvm_sched_in;
> kvm_preempt_ops.sched_out = kvm_sched_out;
>
> + kvm_init_memory_attributes();
> kvm_init_debug();
>
> r = kvm_vfio_ops_init();
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v8 07/46] KVM: Rename memory attribute APIs to prepare for in-place gmem conversion
From: Fuad Tabba @ 2026-06-19 8:16 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-7-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:31, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Sean Christopherson <seanjc@google.com>
>
> Rename memory attribute APIs to add a "vm_" in the name in anticipation of
> moving PRIVATE tracking into guest_memfd, to allow in-place conversion
> between SHARED and PRIVATE. At that point, there will effectively be two
> (potential) sources of memory attributes: the VM and guest_memfd.
>
> No functional change intended.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
Missing SoB (other patches as well, I won't mention it again). But for
this (and other patches I review with a missing SoB fixed):
Reviewed-by: Fuad Tabba <tabba@google.com>
Cheers,
/fuad
> ---
> arch/x86/kvm/mmu/mmu.c | 6 +++---
> include/linux/kvm_host.h | 15 +++++++++++----
> virt/kvm/guest_memfd.c | 6 +++---
> virt/kvm/kvm_main.c | 16 ++++++++--------
> 4 files changed, 25 insertions(+), 18 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index e0005a21b6e22..cbc50aef801fb 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -8087,11 +8087,11 @@ static bool hugepage_has_attrs(struct kvm *kvm, struct kvm_memory_slot *slot,
> const unsigned long end = start + KVM_PAGES_PER_HPAGE(level);
>
> if (level == PG_LEVEL_2M)
> - return kvm_range_has_memory_attributes(kvm, start, end, ~0, attrs);
> + return kvm_range_has_vm_memory_attributes(kvm, start, end, ~0, attrs);
>
> for (gfn = start; gfn < end; gfn += KVM_PAGES_PER_HPAGE(level - 1)) {
> if (hugepage_test_mixed(slot, gfn, level - 1) ||
> - attrs != kvm_get_memory_attributes(kvm, gfn))
> + attrs != kvm_get_vm_memory_attributes(kvm, gfn))
> return false;
> }
> return true;
> @@ -8191,7 +8191,7 @@ void kvm_mmu_init_memslot_memory_attributes(struct kvm *kvm,
> * be manually checked as the attributes may already be mixed.
> */
> for (gfn = start; gfn < end; gfn += nr_pages) {
> - unsigned long attrs = kvm_get_memory_attributes(kvm, gfn);
> + unsigned long attrs = kvm_get_vm_memory_attributes(kvm, gfn);
>
> if (hugepage_has_attrs(kvm, slot, gfn, level, attrs))
> hugepage_clear_mixed(slot, gfn, level);
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index d370e834d619e..eb26d4ea8945a 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -2534,13 +2534,13 @@ static inline bool kvm_memslot_is_gmem_only(const struct kvm_memory_slot *slot)
> }
>
> #ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
> -static inline unsigned long kvm_get_memory_attributes(struct kvm *kvm, gfn_t gfn)
> +static inline unsigned long kvm_get_vm_memory_attributes(struct kvm *kvm, gfn_t gfn)
> {
> return xa_to_value(xa_load(&kvm->mem_attr_array, gfn));
> }
>
> -bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
> - unsigned long mask, unsigned long attrs);
> +bool kvm_range_has_vm_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
> + unsigned long mask, unsigned long attrs);
> bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm,
> struct kvm_gfn_range *range);
> bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,
> @@ -2548,7 +2548,14 @@ bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,
>
> static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
> {
> - return kvm_get_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE;
> + return kvm_get_vm_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE;
> +}
> +static inline bool kvm_mem_range_is_private(struct kvm *kvm, gfn_t start,
> + gfn_t end)
> +{
> + return kvm_range_has_vm_memory_attributes(kvm, start, end,
> + KVM_MEMORY_ATTRIBUTE_PRIVATE,
> + KVM_MEMORY_ATTRIBUTE_PRIVATE);
> }
> #else
> static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
> diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
> index b4c24fdf159f6..8101f64e0366f 100644
> --- a/virt/kvm/guest_memfd.c
> +++ b/virt/kvm/guest_memfd.c
> @@ -915,9 +915,9 @@ static long __kvm_gmem_populate(struct kvm *kvm, struct kvm_memory_slot *slot,
>
> folio_unlock(folio);
>
> - if (!kvm_range_has_memory_attributes(kvm, gfn, gfn + 1,
> - KVM_MEMORY_ATTRIBUTE_PRIVATE,
> - KVM_MEMORY_ATTRIBUTE_PRIVATE)) {
> + if (!kvm_range_has_vm_memory_attributes(kvm, gfn, gfn + 1,
> + KVM_MEMORY_ATTRIBUTE_PRIVATE,
> + KVM_MEMORY_ATTRIBUTE_PRIVATE)) {
> ret = -EINVAL;
> goto out_put_folio;
> }
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 7b989b659cf82..6669f1477013c 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -2419,7 +2419,7 @@ static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm,
> #endif /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */
>
> #ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
> -static u64 kvm_supported_mem_attributes(struct kvm *kvm)
> +static u64 kvm_supported_vm_mem_attributes(struct kvm *kvm)
> {
> #ifdef kvm_arch_has_private_mem
> if (!kvm || kvm_arch_has_private_mem(kvm))
> @@ -2433,19 +2433,19 @@ static u64 kvm_supported_mem_attributes(struct kvm *kvm)
> * Returns true if _all_ gfns in the range [@start, @end) have attributes
> * such that the bits in @mask match @attrs.
> */
> -bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
> - unsigned long mask, unsigned long attrs)
> +bool kvm_range_has_vm_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
> + unsigned long mask, unsigned long attrs)
> {
> XA_STATE(xas, &kvm->mem_attr_array, start);
> unsigned long index;
> void *entry;
>
> - mask &= kvm_supported_mem_attributes(kvm);
> + mask &= kvm_supported_vm_mem_attributes(kvm);
> if (attrs & ~mask)
> return false;
>
> if (end == start + 1)
> - return (kvm_get_memory_attributes(kvm, start) & mask) == attrs;
> + return (kvm_get_vm_memory_attributes(kvm, start) & mask) == attrs;
>
> guard(rcu)();
> if (!attrs)
> @@ -2567,7 +2567,7 @@ static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
> mutex_lock(&kvm->slots_lock);
>
> /* Nothing to do if the entire range has the desired attributes. */
> - if (kvm_range_has_memory_attributes(kvm, start, end, ~0, attributes))
> + if (kvm_range_has_vm_memory_attributes(kvm, start, end, ~0, attributes))
> goto out_unlock;
>
> /*
> @@ -2606,7 +2606,7 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
> /* flags is currently not used. */
> if (attrs->flags)
> return -EINVAL;
> - if (attrs->attributes & ~kvm_supported_mem_attributes(kvm))
> + if (attrs->attributes & ~kvm_supported_vm_mem_attributes(kvm))
> return -EINVAL;
> if (attrs->size == 0 || attrs->address + attrs->size < attrs->address)
> return -EINVAL;
> @@ -4926,7 +4926,7 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
> return 1;
> #ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
> case KVM_CAP_MEMORY_ATTRIBUTES:
> - return kvm_supported_mem_attributes(kvm);
> + return kvm_supported_vm_mem_attributes(kvm);
> #endif
> #ifdef CONFIG_KVM_GUEST_MEMFD
> case KVM_CAP_GUEST_MEMFD:
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v8 05/46] KVM: Make CONFIG_KVM_VM_MEMORY_ATTRIBUTES selectable
From: Fuad Tabba @ 2026-06-19 8:12 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-5-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:31, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Ackerley Tng <ackerleytng@google.com>
>
> Make CONFIG_KVM_VM_MEMORY_ATTRIBUTES selectable, only for (CoCo) VM types
> that might use vm_memory_attributes.
>
> Also document CONFIG_KVM_VM_MEMORY_ATTRIBUTES to specifically be about the
> private/shared attribute.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
You're missing a SoB, but with that fixed:
Reviewed-by: Fuad Tabba <tabba@google.com>
Cheers,
/fuad
> ---
> arch/x86/kvm/Kconfig | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
> index 24f96396cfa1c..c28393dc664eb 100644
> --- a/arch/x86/kvm/Kconfig
> +++ b/arch/x86/kvm/Kconfig
> @@ -81,13 +81,16 @@ config KVM_WERROR
> If in doubt, say "N".
>
> config KVM_VM_MEMORY_ATTRIBUTES
> - bool
> + depends on KVM_SW_PROTECTED_VM || KVM_INTEL_TDX || KVM_AMD_SEV
> + bool "Enable per-VM PRIVATE vs. SHARED attributes (for CoCo VMs)"
> + help
> + Enable support for tracking PRIVATE vs. SHARED memory using per-VM
> + memory attributes.
>
> config KVM_SW_PROTECTED_VM
> bool "Enable support for KVM software-protected VMs"
> depends on EXPERT
> depends on KVM_X86 && X86_64
> - select KVM_VM_MEMORY_ATTRIBUTES
> help
> Enable support for KVM software-protected VMs. Currently, software-
> protected VMs are purely a development and testing vehicle for
> @@ -138,7 +141,6 @@ config KVM_INTEL_TDX
> bool "Intel Trust Domain Extensions (TDX) support"
> default y
> depends on INTEL_TDX_HOST
> - select KVM_VM_MEMORY_ATTRIBUTES
> select HAVE_KVM_ARCH_GMEM_POPULATE
> help
> Provides support for launching Intel Trust Domain Extensions (TDX)
> @@ -162,7 +164,6 @@ config KVM_AMD_SEV
> depends on KVM_AMD && X86_64
> depends on CRYPTO_DEV_SP_PSP && !(KVM_AMD=y && CRYPTO_DEV_CCP_DD=m)
> select ARCH_HAS_CC_PLATFORM
> - select KVM_VM_MEMORY_ATTRIBUTES
> select HAVE_KVM_ARCH_GMEM_PREPARE
> select HAVE_KVM_ARCH_GMEM_INVALIDATE
> select HAVE_KVM_ARCH_GMEM_POPULATE
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v8 04/46] KVM: Decouple kvm_has_arch_private_mem from CONFIG_KVM_VM_MEMORY_ATTRIBUTES
From: Fuad Tabba @ 2026-06-19 8:10 UTC (permalink / raw)
To: ackerleytng
Cc: aik, andrew.jones, binbin.wu, brauner, chao.p.peng, david,
jmattson, jthoughton, michael.roth, oupton, pankaj.gupta, qperret,
rick.p.edgecombe, rientjes, shivankg, steven.price, willy, wyihan,
yan.y.zhao, forkloop, pratyush, suzuki.poulose, aneesh.kumar,
liam, Paolo Bonzini, Sean Christopherson, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers,
Jonathan Corbet, Shuah Khan, Shuah Khan, Vishal Annapurve,
Andrew Morton, Chris Li, Kairui Song, Kemeng Shi, Nhat Pham,
Barry Song, Axel Rasmussen, Yuanchu Xie, Wei Xu, Youngjun Park,
Qi Zheng, Shakeel Butt, Kiryl Shutsemau, Baoquan He,
Jason Gunthorpe, Vlastimil Babka, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <20260618-gmem-inplace-conversion-v8-4-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:31, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Sean Christopherson <seanjc@google.com>
>
> When memory attributes become trackable in guest_memfd, the concept of
> having private memory is no longer dependent on
> CONFIG_KVM_VM_MEMORY_ATTRIBUTES.
>
> With this, on x86, kvm_arch_has_private_mem() is defined if some CoCo
> platform support (or the testing CONFIG_KVM_SW_PROTECTED_VM) is compiled
> in.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> Co-developed-by: Ackerley Tng <ackerleytng@google.com>
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Cheers,
/fuad
> ---
> arch/x86/include/asm/kvm_host.h | 4 +++-
> include/linux/kvm_host.h | 2 +-
> 2 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 8e8eb8a5e8a6b..1bde67cf6eb0e 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -2394,7 +2394,9 @@ void kvm_configure_mmu(bool enable_tdp, int tdp_forced_root_level,
> int tdp_max_root_level, int tdp_huge_page_level);
>
>
> -#ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
> +#if defined(CONFIG_KVM_SW_PROTECTED_VM) || \
> + defined(CONFIG_KVM_INTEL_TDX) || \
> + defined(CONFIG_KVM_AMD_SEV)
> #define kvm_arch_has_private_mem(kvm) ((kvm)->arch.has_private_mem)
> #endif
>
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 201d0f2143976..d370e834d619e 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -722,7 +722,7 @@ static inline int kvm_arch_vcpu_memslots_id(struct kvm_vcpu *vcpu)
> }
> #endif
>
> -#ifndef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
> +#ifndef kvm_arch_has_private_mem
> static inline bool kvm_arch_has_private_mem(struct kvm *kvm)
> {
> return false;
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* [PATCH v2 4/4] rv/rtapp: Add wakeup monitor
From: Nam Cao @ 2026-06-19 7:21 UTC (permalink / raw)
To: Gabriele Monaco, Steven Rostedt, linux-trace-kernel, linux-doc,
linux-kernel
Cc: Nam Cao
In-Reply-To: <cover.1781852967.git.namcao@linutronix.de>
Add a wakeup monitor to detect a lower-priority task waking up a
higher-priority task.
The rtapp/sleep monitor already detects this. However, that monitor
triggers an error in the context of the wakee task and user only gets
the stacktrace of that task. It is also extremely useful to get the
stacktrace of the waker task, which this monitor offers. In other
words, this monitor complements the rtapp/sleep monitor.
Signed-off-by: Nam Cao <namcao@linutronix.de>
---
Documentation/trace/rv/monitor_rtapp.rst | 20 +++
kernel/trace/rv/Kconfig | 1 +
kernel/trace/rv/Makefile | 1 +
kernel/trace/rv/monitors/rtapp/Kconfig | 2 +-
kernel/trace/rv/monitors/wakeup/Kconfig | 16 ++
kernel/trace/rv/monitors/wakeup/wakeup.c | 153 ++++++++++++++++++
kernel/trace/rv/monitors/wakeup/wakeup.h | 92 +++++++++++
.../trace/rv/monitors/wakeup/wakeup_trace.h | 14 ++
kernel/trace/rv/rv_trace.h | 1 +
tools/verification/models/rtapp/wakeup.ltl | 5 +
10 files changed, 304 insertions(+), 1 deletion(-)
create mode 100644 kernel/trace/rv/monitors/wakeup/Kconfig
create mode 100644 kernel/trace/rv/monitors/wakeup/wakeup.c
create mode 100644 kernel/trace/rv/monitors/wakeup/wakeup.h
create mode 100644 kernel/trace/rv/monitors/wakeup/wakeup_trace.h
create mode 100644 tools/verification/models/rtapp/wakeup.ltl
diff --git a/Documentation/trace/rv/monitor_rtapp.rst b/Documentation/trace/rv/monitor_rtapp.rst
index 502d3ea412eb..238b59395ff5 100644
--- a/Documentation/trace/rv/monitor_rtapp.rst
+++ b/Documentation/trace/rv/monitor_rtapp.rst
@@ -124,3 +124,23 @@ to handle some special cases:
real-time-safe because preemption is disabled for the duration.
- `FUTEX_LOCK_PI` is included in the allowlist for the same reason as
`BLOCK_ON_RT_MUTEX`.
+
+Monitor wakeup
+++++++++++++++
+
+The `wakeup` monitor reports real-time threads being woken by lower-priority threads,
+which is a hint of priority inversion. Its specification is::
+
+ RULE = always (((RT and USER_THREAD) imply
+ (not (WOKEN_BY_LOWER_PRIO or WOKEN_BY_SOFTIRQ)) or ALLOWLIST))
+
+ ALLOWLIST = BLOCK_ON_RT_MUTEX
+ or FUTEX_LOCK_PI
+
+The `sleep` monitor already reports this type of problem. The difference is the
+context in which the problem is reported. While the `sleep` monitor reports the problem
+in the context of the wakee, this `wakeup` monitor reports the problem in the context of
+the waker. This monitor complement the `sleep` monitor, giving user better
+understanding of the issue. For instance, to debug a lower-priority task waking a
+higher-priority task scenario, user can enable both `wakeup` monitor and `sleep`
+monitor to get the stack traces of both tasks.
diff --git a/kernel/trace/rv/Kconfig b/kernel/trace/rv/Kconfig
index 3884b14df375..4d3a14a0bac2 100644
--- a/kernel/trace/rv/Kconfig
+++ b/kernel/trace/rv/Kconfig
@@ -76,6 +76,7 @@ source "kernel/trace/rv/monitors/opid/Kconfig"
source "kernel/trace/rv/monitors/rtapp/Kconfig"
source "kernel/trace/rv/monitors/pagefault/Kconfig"
source "kernel/trace/rv/monitors/sleep/Kconfig"
+source "kernel/trace/rv/monitors/wakeup/Kconfig"
# Add new rtapp monitors here
source "kernel/trace/rv/monitors/stall/Kconfig"
diff --git a/kernel/trace/rv/Makefile b/kernel/trace/rv/Makefile
index 94498da35b37..c2c0e4142eb4 100644
--- a/kernel/trace/rv/Makefile
+++ b/kernel/trace/rv/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_RV_MON_OPID) += monitors/opid/opid.o
obj-$(CONFIG_RV_MON_STALL) += monitors/stall/stall.o
obj-$(CONFIG_RV_MON_DEADLINE) += monitors/deadline/deadline.o
obj-$(CONFIG_RV_MON_NOMISS) += monitors/nomiss/nomiss.o
+obj-$(CONFIG_RV_MON_WAKEUP) += monitors/wakeup/wakeup.o
# Add new monitors here
obj-$(CONFIG_RV_REACTORS) += rv_reactors.o
obj-$(CONFIG_RV_REACT_PRINTK) += reactor_printk.o
diff --git a/kernel/trace/rv/monitors/rtapp/Kconfig b/kernel/trace/rv/monitors/rtapp/Kconfig
index 1ce9370a9ba8..1fcd7a400ded 100644
--- a/kernel/trace/rv/monitors/rtapp/Kconfig
+++ b/kernel/trace/rv/monitors/rtapp/Kconfig
@@ -1,6 +1,6 @@
config RV_MON_RTAPP
depends on RV
- depends on RV_PER_TASK_MONITORS >= 2
+ depends on RV_PER_TASK_MONITORS >= 3
bool "rtapp monitor"
help
Collection of monitors to check for common problems with real-time
diff --git a/kernel/trace/rv/monitors/wakeup/Kconfig b/kernel/trace/rv/monitors/wakeup/Kconfig
new file mode 100644
index 000000000000..ec3a5c06a8c4
--- /dev/null
+++ b/kernel/trace/rv/monitors/wakeup/Kconfig
@@ -0,0 +1,16 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+config RV_MON_WAKEUP
+ depends on RV
+ depends on RV_MON_RTAPP
+ depends on HAVE_SYSCALL_TRACEPOINTS
+ default y
+ select LTL_MON_EVENTS_ID
+ bool "wakeup monitor"
+ help
+ This monitor detects a lower-priority task waking up a
+ higher-priority task. The RV_MON_SLEEP monitor already
+ detects this case, but this monitor detects in the context
+ of the waker task instead. This and RV_MON_SLEEP can be
+ enabled together to get the stacktrace of both the waker
+ task and the wakee task.
diff --git a/kernel/trace/rv/monitors/wakeup/wakeup.c b/kernel/trace/rv/monitors/wakeup/wakeup.c
new file mode 100644
index 000000000000..01b47416f24e
--- /dev/null
+++ b/kernel/trace/rv/monitors/wakeup/wakeup.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/ftrace.h>
+#include <linux/tracepoint.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/rv.h>
+#include <rv/instrumentation.h>
+
+#define MODULE_NAME "wakeup"
+
+#include <trace/events/syscalls.h>
+#include <trace/events/sched.h>
+#include <trace/events/lock.h>
+#include <uapi/linux/futex.h>
+
+#include <rv_trace.h>
+#include <monitors/rtapp/rtapp.h>
+
+
+#ifndef __NR_futex
+#define __NR_futex (-__COUNTER__)
+#endif
+#ifndef __NR_futex_time64
+#define __NR_futex_time64 (-__COUNTER__)
+#endif
+
+#include "wakeup.h"
+#include <rv/ltl_monitor.h>
+
+static void ltl_atoms_fetch(struct task_struct *task, struct ltl_monitor *mon)
+{
+ /*
+ * This includes "actual" real-time tasks and also PI-boosted
+ * tasks. A task being PI-boosted means it is blocking an "actual"
+ * real-task, therefore it should also obey the monitor's rule,
+ * otherwise the "actual" real-task may be delayed.
+ */
+ ltl_atom_set(mon, LTL_RT, rt_or_dl_task(task));
+}
+
+static void ltl_atoms_init(struct task_struct *task, struct ltl_monitor *mon, bool task_creation)
+{
+ ltl_atom_set(mon, LTL_WOKEN_BY_LOWER_PRIO, false);
+ ltl_atom_set(mon, LTL_WOKEN_BY_SOFTIRQ, false);
+
+ if (task_creation) {
+ ltl_atom_set(mon, LTL_BLOCK_ON_RT_MUTEX, false);
+ ltl_atom_set(mon, LTL_FUTEX_LOCK_PI, false);
+ }
+
+ ltl_atom_set(mon, LTL_USER_THREAD, !(task->flags & PF_KTHREAD));
+}
+
+static void handle_sched_waking(void *data, struct task_struct *task)
+{
+ if (in_task()) {
+ if (current->prio > task->prio)
+ ltl_atom_pulse(task, LTL_WOKEN_BY_LOWER_PRIO, true);
+ } else if (in_serving_softirq()) {
+ ltl_atom_pulse(task, LTL_WOKEN_BY_SOFTIRQ, true);
+ }
+}
+
+static void handle_contention_begin(void *data, void *lock, unsigned int flags)
+{
+ if (flags & LCB_F_RT)
+ ltl_atom_update(current, LTL_BLOCK_ON_RT_MUTEX, true);
+}
+
+static void handle_contention_end(void *data, void *lock, int ret)
+{
+ ltl_atom_update(current, LTL_BLOCK_ON_RT_MUTEX, false);
+}
+
+static void handle_sys_enter(void *data, struct pt_regs *regs, long id)
+{
+ unsigned long args[6];
+ int op, cmd;
+
+ switch (id) {
+ case __NR_futex:
+ case __NR_futex_time64:
+ syscall_get_arguments(current, regs, args);
+ op = args[1];
+ cmd = op & FUTEX_CMD_MASK;
+
+ switch (cmd) {
+ case FUTEX_LOCK_PI:
+ case FUTEX_LOCK_PI2:
+ ltl_atom_update(current, LTL_FUTEX_LOCK_PI, true);
+ break;
+ }
+ break;
+ }
+}
+
+static void handle_sys_exit(void *data, struct pt_regs *regs, long ret)
+{
+ ltl_atom_update(current, LTL_FUTEX_LOCK_PI, false);
+}
+
+static int enable_wakeup(void)
+{
+ int retval;
+
+ retval = ltl_monitor_init();
+ if (retval)
+ return retval;
+
+ rv_attach_trace_probe("rtapp_wakeup", sched_waking, handle_sched_waking);
+ rv_attach_trace_probe("rtapp_wakeup", contention_begin, handle_contention_begin);
+ rv_attach_trace_probe("rtapp_wakeup", contention_end, handle_contention_end);
+ rv_attach_trace_probe("rtapp_wakeup", sys_enter, handle_sys_enter);
+ rv_attach_trace_probe("rtapp_wakeup", sys_exit, handle_sys_exit);
+
+ return 0;
+}
+
+static void disable_wakeup(void)
+{
+ rv_detach_trace_probe("rtapp_wakeup", sched_waking, handle_sched_waking);
+ rv_detach_trace_probe("rtapp_wakeup", contention_begin, handle_contention_begin);
+ rv_detach_trace_probe("rtapp_wakeup", contention_end, handle_contention_end);
+ rv_detach_trace_probe("rtapp_wakeup", sys_enter, handle_sys_enter);
+ rv_detach_trace_probe("rtapp_wakeup", sys_exit, handle_sys_exit);
+
+ ltl_monitor_destroy();
+}
+
+static struct rv_monitor rv_wakeup = {
+ .name = "wakeup",
+ .description = "Monitor that real-time tasks are not woken by lower-priority tasks",
+ .enable = enable_wakeup,
+ .disable = disable_wakeup,
+};
+
+static int __init register_wakeup(void)
+{
+ return rv_register_monitor(&rv_wakeup, &rv_rtapp);
+}
+
+static void __exit unregister_wakeup(void)
+{
+ rv_unregister_monitor(&rv_wakeup);
+}
+
+module_init(register_wakeup);
+module_exit(unregister_wakeup);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Nam Cao <namcao@linutronix.de>");
+MODULE_DESCRIPTION("Monitor that real-time tasks are not woken by lower-priority tasks");
diff --git a/kernel/trace/rv/monitors/wakeup/wakeup.h b/kernel/trace/rv/monitors/wakeup/wakeup.h
new file mode 100644
index 000000000000..6f80da64e0e1
--- /dev/null
+++ b/kernel/trace/rv/monitors/wakeup/wakeup.h
@@ -0,0 +1,92 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * C implementation of Buchi automaton, automatically generated by
+ * tools/verification/rvgen from the linear temporal logic specification.
+ * For further information, see kernel documentation:
+ * Documentation/trace/rv/linear_temporal_logic.rst
+ */
+
+#include <linux/rv.h>
+
+#define MONITOR_NAME wakeup
+
+enum ltl_atom {
+ LTL_BLOCK_ON_RT_MUTEX,
+ LTL_FUTEX_LOCK_PI,
+ LTL_RT,
+ LTL_USER_THREAD,
+ LTL_WOKEN_BY_LOWER_PRIO,
+ LTL_WOKEN_BY_SOFTIRQ,
+ LTL_NUM_ATOM
+};
+static_assert(LTL_NUM_ATOM <= RV_MAX_LTL_ATOM);
+
+static const char *ltl_atom_str(enum ltl_atom atom)
+{
+ static const char *const names[] = {
+ "bl_on_rt_mu",
+ "fu_lo_pi",
+ "rt",
+ "us_th",
+ "wo_lo_pr",
+ "wo_so",
+ };
+
+ return names[atom];
+}
+
+enum ltl_buchi_state {
+ S0,
+ RV_NUM_BA_STATES
+};
+static_assert(RV_NUM_BA_STATES <= RV_MAX_BA_STATES);
+
+static void ltl_start(struct task_struct *task, struct ltl_monitor *mon)
+{
+ bool woken_by_softirq = test_bit(LTL_WOKEN_BY_SOFTIRQ, mon->atoms);
+ bool woken_by_lower_prio = test_bit(LTL_WOKEN_BY_LOWER_PRIO, mon->atoms);
+ bool user_thread = test_bit(LTL_USER_THREAD, mon->atoms);
+ bool rt = test_bit(LTL_RT, mon->atoms);
+ bool futex_lock_pi = test_bit(LTL_FUTEX_LOCK_PI, mon->atoms);
+ bool block_on_rt_mutex = test_bit(LTL_BLOCK_ON_RT_MUTEX, mon->atoms);
+ bool val9 = block_on_rt_mutex || futex_lock_pi;
+ bool val6 = !woken_by_softirq;
+ bool val5 = !woken_by_lower_prio;
+ bool val8 = val5 && val6;
+ bool val10 = val8 || val9;
+ bool val3 = !user_thread;
+ bool val2 = !rt;
+ bool val4 = val2 || val3;
+ bool val11 = val4 || val10;
+
+ if (val11)
+ __set_bit(S0, mon->states);
+}
+
+static void
+ltl_possible_next_states(struct ltl_monitor *mon, unsigned int state, unsigned long *next)
+{
+ bool woken_by_softirq = test_bit(LTL_WOKEN_BY_SOFTIRQ, mon->atoms);
+ bool woken_by_lower_prio = test_bit(LTL_WOKEN_BY_LOWER_PRIO, mon->atoms);
+ bool user_thread = test_bit(LTL_USER_THREAD, mon->atoms);
+ bool rt = test_bit(LTL_RT, mon->atoms);
+ bool futex_lock_pi = test_bit(LTL_FUTEX_LOCK_PI, mon->atoms);
+ bool block_on_rt_mutex = test_bit(LTL_BLOCK_ON_RT_MUTEX, mon->atoms);
+ bool val9 = block_on_rt_mutex || futex_lock_pi;
+ bool val6 = !woken_by_softirq;
+ bool val5 = !woken_by_lower_prio;
+ bool val8 = val5 && val6;
+ bool val10 = val8 || val9;
+ bool val3 = !user_thread;
+ bool val2 = !rt;
+ bool val4 = val2 || val3;
+ bool val11 = val4 || val10;
+
+ switch (state) {
+ case S0:
+ if (val11)
+ __set_bit(S0, next);
+ break;
+ }
+}
diff --git a/kernel/trace/rv/monitors/wakeup/wakeup_trace.h b/kernel/trace/rv/monitors/wakeup/wakeup_trace.h
new file mode 100644
index 000000000000..7e056183f920
--- /dev/null
+++ b/kernel/trace/rv/monitors/wakeup/wakeup_trace.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * Snippet to be included in rv_trace.h
+ */
+
+#ifdef CONFIG_RV_MON_WAKEUP
+DEFINE_EVENT(event_ltl_monitor_id, event_wakeup,
+ TP_PROTO(struct task_struct *task, char *states, char *atoms, char *next),
+ TP_ARGS(task, states, atoms, next));
+DEFINE_EVENT(error_ltl_monitor_id, error_wakeup,
+ TP_PROTO(struct task_struct *task),
+ TP_ARGS(task));
+#endif /* CONFIG_RV_MON_WAKEUP */
diff --git a/kernel/trace/rv/rv_trace.h b/kernel/trace/rv/rv_trace.h
index 9622c269789c..2f8a932432c9 100644
--- a/kernel/trace/rv/rv_trace.h
+++ b/kernel/trace/rv/rv_trace.h
@@ -241,6 +241,7 @@ DECLARE_EVENT_CLASS(error_ltl_monitor_id,
);
#include <monitors/pagefault/pagefault_trace.h>
#include <monitors/sleep/sleep_trace.h>
+#include <monitors/wakeup/wakeup_trace.h>
// Add new monitors based on CONFIG_LTL_MON_EVENTS_ID here
#endif /* CONFIG_LTL_MON_EVENTS_ID */
diff --git a/tools/verification/models/rtapp/wakeup.ltl b/tools/verification/models/rtapp/wakeup.ltl
new file mode 100644
index 000000000000..a5d63ca0811a
--- /dev/null
+++ b/tools/verification/models/rtapp/wakeup.ltl
@@ -0,0 +1,5 @@
+RULE = always (((RT and USER_THREAD) imply
+ (not (WOKEN_BY_LOWER_PRIO or WOKEN_BY_SOFTIRQ)) or ALLOWLIST))
+
+ALLOWLIST = BLOCK_ON_RT_MUTEX
+ or FUTEX_LOCK_PI
--
2.47.3
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