* Re: [PATCH v8 24/46] KVM: guest_memfd: Make in-place conversion the default
From: Ackerley Tng @ 2026-06-25 0:05 UTC (permalink / raw)
To: Yan Zhao
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, tabba, willy,
wyihan, 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: <aji/2svhcc84rn5w@yzhao56-desk.sh.intel.com>
Yan Zhao <yan.y.zhao@intel.com> writes:
>
> [...snip...]
>
>>
>> #ifdef kvm_arch_has_private_mem
>> -bool __ro_after_init gmem_in_place_conversion = false;
>> +bool __ro_after_init gmem_in_place_conversion = !IS_ENABLED(CONFIG_KVM_VM_MEMORY_ATTRIBUTES);
>> +module_param(gmem_in_place_conversion, bool, 0444);
>
> With gmem_in_place_conversion=true, userspace can create guest_memfd without the
> MMAP flag. In such cases, shared memory is allocated from different backends.
> This means this module parameter only enables per-gmem memory attribute and does
> not guarantee that gmem in-place conversion will actually occur.
>
> To avoid confusion, could we rename this module parameter to something more
> accurate, such as gmem_memory_attribute?
>
I asked Sean about this after getting some fixes off list. Sean said
gmem_in_place_conversion is named for a host admin to use, and something
like gmem_memory_attributes is too much implementation details for the
admin.
Sean, would you reconsider since Yan also asked? If the admin compiled
the kernel knowing what CONFIG_KVM_VM_MEMORY_ATTRIBUTES means, then the
admin would also be able to use a param like gmem_memory_attributes?
There's the additional benefit that the similar naming aids in
understanding for both the admin and software engineers.
Either way, in the next revision, I'll also add this documentation for
this module_param:
Setting the module parameter gmem_in_place_conversion to true will
enable the KVM_SET_MEMORY_ATTRIBUTES2 guest_memfd ioctl and disables
the KVM_SET_MEMORY_ATTRIBUTES VM ioctl. If gmem_in_place_conversion is
true, the private/shared attribute will be tracked per-guest_memfd
instead of per-VM.
Let me know what y'all think of the wording!
>>
>> [...snip...]
>>
^ permalink raw reply
* Re: [External Mail] [PATCH v2 1/7] net: wwan: t9xx: Add PCIe core
From: Jakub Kicinski @ 2026-06-24 23:35 UTC (permalink / raw)
To: Wu. JackBB (GSM)
Cc: Loic Poulain, Sergey Ryazanov, Johannes Berg, Andrew Lunn,
David S. Miller, Eric Dumazet, Paolo Abeni, Wen-Zhi Huang,
Shi-Wei Yeh, Minano Tseng, Matthias Brugger,
AngeloGioacchino Del Regno, Simon Horman, Jonathan Corbet,
Shuah Khan, linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-mediatek@lists.infradead.org, linux-doc@vger.kernel.org
In-Reply-To: <b02c0e1e9f0449f2b819197e4329373b@compal.com>
On Wed, 24 Jun 2026 09:15:17 +0000 Wu. JackBB (GSM) wrote:
> ================================================================================================================================================================
> This message may contain information which is private, privileged or confidential of Compal Electronics, Inc. If you are not the intended recipient of this message, please notify the sender and destroy/delete the message. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon this information, by persons or entities other than the intended recipient is prohibited.
> ================================================================================================================================================================
If you want to do anything upstream you have to get rid of this first.
^ permalink raw reply
* Re: [PATCH v8 01/10] tracing/probes: Make the $ prefix mandatory for comm access
From: Masami Hiramatsu @ 2026-06-24 23:33 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: <178231209724.732967.12049805699091810641.stgit@devnote2>
On Wed, 24 Jun 2026 23:41:37 +0900
"Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:
> From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
>
> Since $comm or $COMM are not event field but special fetcharg
> variables to access current->comm, It should not be accessed
> without '$' prefix even with typecast.
>
Let me pick this to probes/core.
Thanks,
> Fixes: 69efd863a785 ("tracing/eprobes: Allow use of BTF names to dereference pointers")
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> ---
> Changes in v8:
> - Newly added.
> ---
> kernel/trace/trace_probe.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
> index c10bbb0df7b9..0da7c0b53ba7 100644
> --- a/kernel/trace/trace_probe.c
> +++ b/kernel/trace/trace_probe.c
> @@ -342,10 +342,6 @@ static int parse_trace_event(char *arg, struct fetch_insn *code,
> ret = parse_trace_event_arg(arg, code, ctx);
> if (!ret)
> return 0;
> - if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
> - code->op = FETCH_OP_COMM;
> - return 0;
> - }
> return -EINVAL;
> }
>
> @@ -1065,8 +1061,14 @@ static int parse_probe_vars(char *orig_arg, const struct fetch_type *t,
> int len;
>
> if (ctx->flags & TPARG_FL_TEVENT) {
> - if (parse_trace_event(arg, code, ctx) < 0)
> + if (parse_trace_event(arg, code, ctx) < 0) {
> + /* 'comm' should be checked after field parsing. */
> + if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
> + code->op = FETCH_OP_COMM;
> + return 0;
> + }
> goto inval;
> + }
> return 0;
> }
>
>
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply
* Re: [PATCH 2/3] dt-bindings: hwmon: pmbus: Support for onsemi's FD5121
From: Guenter Roeck @ 2026-06-24 23:05 UTC (permalink / raw)
To: Selvamani Rajagopal, Conor Dooley
Cc: Jonathan Corbet, Shuah Khan, Rob Herring, Krzysztof Kozlowski,
Conor Dooley, linux-hwmon@vger.kernel.org,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
devicetree@vger.kernel.org
In-Reply-To: <CYYPR02MB9828EECB3F6AFDD2A7BD3E9B83ED2@CYYPR02MB9828.namprd02.prod.outlook.com>
On 6/24/26 15:36, Selvamani Rajagopal wrote:
>> -----Original Message-----
>> From: Conor Dooley <conor@kernel.org>
>> Subject: Re: [PATCH 2/3] dt-bindings: hwmon: pmbus: Support for onsemi's FD5121
>>
>>
>> My point is that what's actually being controlled is missing. Maybe it
>> is obvious to you, but it is not to me. Your nodename in your example is
>
>
> You are right. This chip may not be a "controller" in the traditional sense as it doesn't control anything.
> We can change node naming to sensor or regulator so that it aligns with the convention.
>
One of the problems here is that the chip datasheet is not public,
so we can not verify what this actually is. The only available
public document appears to be the "onsemi FD512x Ax Digital Controller
User Manual" which describes the chip as follows.
"The FD512x Digital Controller is a programmable device designed
for machine vendors to configure their equipment at the factory."
That really does not explain anything at all, and actually looks like
an AI generated summary with the AI not understanding what it is talking
about. According to the onsemi web page, the chip does not exist,
and it appears that it is not available to buy from any distributors
either.
Guenter
>
>>> + fd5121@50 {
>> which doesn't comply with node naming requirements and I wanted to come
>> up with a suggestion for what it should be.
>> I am assuming that its power or voltage that you're controlling so
>> either it should be hwmon@ or regulator@.
>>
>
^ permalink raw reply
* Re: [PATCH v8 23/46] KVM: TDX: Make source page optional for KVM_TDX_INIT_MEM_REGION
From: Ackerley Tng @ 2026-06-24 23:00 UTC (permalink / raw)
To: Sean Christopherson, Yan Zhao
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, tabba, willy,
wyihan, forkloop, pratyush, suzuki.poulose, aneesh.kumar, liam,
Paolo Bonzini, 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: <ajxasFBzp_9KnQLq@google.com>
Sean Christopherson <seanjc@google.com> writes:
> On Tue, Jun 23, 2026, Yan Zhao wrote:
>> On Tue, Jun 23, 2026 at 01:16:14PM +0800, Yan Zhao wrote:
>> > On Mon, Jun 22, 2026 at 06:22:45PM -0700, Sean Christopherson wrote:
>> > > On Mon, Jun 22, 2026, Yan Zhao wrote:
>> > > > On Thu, Jun 18, 2026 at 05:32:00PM -0700, Ackerley Tng via B4 Relay wrote:
>> > > > > 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)
>> > > > When userspace turns on gmem_in_place_conversion while creating guest_memfd
>> > > > without the MMAP flag, the absence of src_page should still be treated as an
>> > > > error.
>> > >
>> > > Why MMAP?
>> > Hmm, I was showing a scenario that in-place conversion couldn't occur.
>> > I didn't mean that with the MMAP flag, mmap() and user write must occur.
>> >
>> > > Shouldn't this be a general "if (!src_page && !up-to-date)"? Just
>> > > because userspace _can_ mmap() the memory doesn't mean userspace _has_ mmap()'d
>> > > and written memory. And when write() lands, MMAP wouldn't be necessary to
>> > > initialize the memory.
>> > Do you mean using up-to-date flag as below?
>
> Yes? I didn't actually look at the implementation details.
>
>> > if (!src_page) {
>> > src_page = pfn_to_page(pfn);
>> > if (!folio_test_uptodate(page_folio(src_page)))
>> > return -EOPNOTSUPP;
>> > }
Yan is right that with the earlier patch "Zero page while getting pfn",
folio_test_uptodate() here will always return true.
Actually, this is an alternative fix for the issue Sashiko pointed out
on v7 where userspace can do a populate() (either TDX or SNP) without
first allocating the page, with src_address == NULL, and leak
uninitialized memory into the guest.
Advantage of using the uptodate check in populate: if the host never
allocates the page, populate doesn't incur zeroing before writing the
page anyway in populate().
Disadvantage: Both TDX and SNP will have to implement this uptodate
check. guest_memfd can't check centrally because for SNP, for a
PAGE_TYPE_ZERO, !src_page should be allowed with a !uptodate page since
firmware will zero and there's no leakage of uninitialized host memory?
>>
>> Another concern with this fix is that:
>> commit "KVM: guest_memfd: Zero page while getting pfn" [1] always marks the
>> folio uptodate before reaching post_populate().
>>
>> [1] https://lore.kernel.org/all/20260618-gmem-inplace-conversion-v8-21-9d2959357853@google.com/
>>
>> > One concern is that TDX now does not much care about the up-to-date flag since
>> > TDX doesn't rely on the flag to clear pages on conversions.
>> > I'm not sure if the flag can be reliably checked in this case. e.g.,
>> > now the whole folio is marked up-to-date even if only part of it is faulted by
>> > user access.
>> > Ensuring that the up-to-date flag works correctly with huge page support seems
>> > to have more effort than introducing a dedicated flag for TDX.
>> >
>> > > > Additionally, to properly enable in-place copying for the TDX initial memory
>> > > > region, userspace must not only specify source_addr to NULL, but also follow
>> > > > a specific sequence (where steps 1/2/3/7 are required only for in-place copy):
>> > > > 1. create guest_memfd with MMAP flag
>> > > > 2. mmap the guest_memfd.
>> > > > 3. convert the initial memory range to shared.
>> > > > 4. copy initial content to the source page.
>> > > > 5. convert the initial memory range to private
>> > > > 6. invoke ioctl KVM_TDX_INIT_MEM_REGION.
>> > > > 7. do not unmap the source backend.
>> > > >
>> > > > So, would it be reasonable to introduce a dedicated flag that allows userspace
>> > > > to explicitly opt into the in-place copy functionality? e.g.,
>> > >
>> > > Why? It's userspace's responsibility to get the above right. If userspace fails
>> > > to provide a src_page when it doesn't want in-place copy, that's a userspace bug.
Yan, is your concern that userspace forgot to update the code and
forgets to provide a src_page, and if we keep the "Zero page while
getting pfn" patch, ends up with the guest silently having a zero page?
I think that would be found quite early in userspace VMM testing...
>> > I mean if userspace specifies a NULL source_addr by mistake, it's better for
>> > kernel to detect this mistake, similar to how it validates whether source_addr
>> > is PAGE_ALIGNED.
>
> The alignment case is different. If userspace provides an unaligned value, KVM
> *can't* do what userspace is asking because hardware and thus KVM only supports
> converting on page boundaries.
>
> For a NULL source, KVM can still do what userspace is asking. Rejecting userspace's
> request would then be making assumptions about what userspace wants.
>
Also, +1 on this, what if userspace, knowing that pages are zeroed on
allocation, actually wants to rely on that to get a zero page in the guest?
>> > Since userspace already needs to perform additional steps to enable in-place
>> > copy, specifying a dedicated flag to indicate that the NULL source_addr is
>> > intentional seems like a reasonable burden.
>
> I don't see how it adds any value. I wouldn't be at all surprised if most VMMs
> just wen up with code that does:
>
> if (in-place) {
> src = NULL;
> flags |= KVM_TDX_IN_PLACE_COPY_INITIAL_MEMORY_REGION;
> }
^ permalink raw reply
* RE: [PATCH 2/3] dt-bindings: hwmon: pmbus: Support for onsemi's FD5121
From: Selvamani Rajagopal @ 2026-06-24 22:36 UTC (permalink / raw)
To: Conor Dooley
Cc: Guenter Roeck, Jonathan Corbet, Shuah Khan, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, linux-hwmon@vger.kernel.org,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
devicetree@vger.kernel.org
In-Reply-To: <20260623-scared-judgingly-7efc1c188670@spud>
> -----Original Message-----
> From: Conor Dooley <conor@kernel.org>
> Subject: Re: [PATCH 2/3] dt-bindings: hwmon: pmbus: Support for onsemi's FD5121
>
>
> My point is that what's actually being controlled is missing. Maybe it
> is obvious to you, but it is not to me. Your nodename in your example is
You are right. This chip may not be a "controller" in the traditional sense as it doesn't control anything.
We can change node naming to sensor or regulator so that it aligns with the convention.
> > + fd5121@50 {
> which doesn't comply with node naming requirements and I wanted to come
> up with a suggestion for what it should be.
> I am assuming that its power or voltage that you're controlling so
> either it should be hwmon@ or regulator@.
>
^ permalink raw reply
* Re: [PATCH v8 22/46] KVM: SEV: Make 'uaddr' parameter optional for KVM_SEV_SNP_LAUNCH_UPDATE
From: Ackerley Tng @ 2026-06-24 22:31 UTC (permalink / raw)
To: Fuad Tabba
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+EHjTz3SW50EzxgXm8VysoaM21RReUVG2px_WUYU7zUwjXnpQ@mail.gmail.com>
Fuad Tabba <tabba@google.com> writes:
>
> [...snip...]
>
>> 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.
>
Will fix in the next revision. Thanks!
> Cheers,
> /fuad
>
>>
>> [...snip...]
>>
^ permalink raw reply
* Re: [PATCH v8 23/46] KVM: TDX: Make source page optional for KVM_TDX_INIT_MEM_REGION
From: Sean Christopherson @ 2026-06-24 22:31 UTC (permalink / raw)
To: Yan Zhao
Cc: 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, forkloop, pratyush, suzuki.poulose,
aneesh.kumar, liam, Paolo Bonzini, 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: <ajpGxu2uQys+S2F8@yzhao56-desk.sh.intel.com>
On Tue, Jun 23, 2026, Yan Zhao wrote:
> On Tue, Jun 23, 2026 at 01:16:14PM +0800, Yan Zhao wrote:
> > On Mon, Jun 22, 2026 at 06:22:45PM -0700, Sean Christopherson wrote:
> > > On Mon, Jun 22, 2026, Yan Zhao wrote:
> > > > On Thu, Jun 18, 2026 at 05:32:00PM -0700, Ackerley Tng via B4 Relay wrote:
> > > > > 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)
> > > > When userspace turns on gmem_in_place_conversion while creating guest_memfd
> > > > without the MMAP flag, the absence of src_page should still be treated as an
> > > > error.
> > >
> > > Why MMAP?
> > Hmm, I was showing a scenario that in-place conversion couldn't occur.
> > I didn't mean that with the MMAP flag, mmap() and user write must occur.
> >
> > > Shouldn't this be a general "if (!src_page && !up-to-date)"? Just
> > > because userspace _can_ mmap() the memory doesn't mean userspace _has_ mmap()'d
> > > and written memory. And when write() lands, MMAP wouldn't be necessary to
> > > initialize the memory.
> > Do you mean using up-to-date flag as below?
Yes? I didn't actually look at the implementation details.
> > if (!src_page) {
> > src_page = pfn_to_page(pfn);
> > if (!folio_test_uptodate(page_folio(src_page)))
> > return -EOPNOTSUPP;
> > }
>
> Another concern with this fix is that:
> commit "KVM: guest_memfd: Zero page while getting pfn" [1] always marks the
> folio uptodate before reaching post_populate().
>
> [1] https://lore.kernel.org/all/20260618-gmem-inplace-conversion-v8-21-9d2959357853@google.com/
>
> > One concern is that TDX now does not much care about the up-to-date flag since
> > TDX doesn't rely on the flag to clear pages on conversions.
> > I'm not sure if the flag can be reliably checked in this case. e.g.,
> > now the whole folio is marked up-to-date even if only part of it is faulted by
> > user access.
> > Ensuring that the up-to-date flag works correctly with huge page support seems
> > to have more effort than introducing a dedicated flag for TDX.
> >
> > > > Additionally, to properly enable in-place copying for the TDX initial memory
> > > > region, userspace must not only specify source_addr to NULL, but also follow
> > > > a specific sequence (where steps 1/2/3/7 are required only for in-place copy):
> > > > 1. create guest_memfd with MMAP flag
> > > > 2. mmap the guest_memfd.
> > > > 3. convert the initial memory range to shared.
> > > > 4. copy initial content to the source page.
> > > > 5. convert the initial memory range to private
> > > > 6. invoke ioctl KVM_TDX_INIT_MEM_REGION.
> > > > 7. do not unmap the source backend.
> > > >
> > > > So, would it be reasonable to introduce a dedicated flag that allows userspace
> > > > to explicitly opt into the in-place copy functionality? e.g.,
> > >
> > > Why? It's userspace's responsibility to get the above right. If userspace fails
> > > to provide a src_page when it doesn't want in-place copy, that's a userspace bug.
> > I mean if userspace specifies a NULL source_addr by mistake, it's better for
> > kernel to detect this mistake, similar to how it validates whether source_addr
> > is PAGE_ALIGNED.
The alignment case is different. If userspace provides an unaligned value, KVM
*can't* do what userspace is asking because hardware and thus KVM only supports
converting on page boundaries.
For a NULL source, KVM can still do what userspace is asking. Rejecting userspace's
request would then be making assumptions about what userspace wants.
> > Since userspace already needs to perform additional steps to enable in-place
> > copy, specifying a dedicated flag to indicate that the NULL source_addr is
> > intentional seems like a reasonable burden.
I don't see how it adds any value. I wouldn't be at all surprised if most VMMs
just wen up with code that does:
if (in-place) {
src = NULL;
flags |= KVM_TDX_IN_PLACE_COPY_INITIAL_MEMORY_REGION;
}
^ permalink raw reply
* Re: [PATCH v8 21/46] KVM: guest_memfd: Zero page while getting pfn
From: Ackerley Tng @ 2026-06-24 22:30 UTC (permalink / raw)
To: Yan Zhao
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, tabba, willy,
wyihan, 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: <ajpKK/SyRh8LExrY@yzhao56-desk.sh.intel.com>
Yan Zhao <yan.y.zhao@intel.com> writes:
> On Thu, Jun 18, 2026 at 05:31:58PM -0700, Ackerley Tng via B4 Relay 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>
>> ---
>> 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);
>> + }
> Note:
> In the __kvm_gmem_populate() path, this folio_mark_uptodate() call makes the
> later one after post_populate() pointless.
>
> __kvm_gmem_populate
> |1.__kvm_gmem_get_pfn
> | |->folio = kvm_gmem_get_folio()
> | | if (!folio_test_uptodate(folio))
> | | folio_mark_uptodate(folio);
> |2. ret = post_populate()
> |3. if (!ret)
> | folio_mark_uptodate(folio);
>
Good point! I'll remove the folio_mark_uptodate() in the populate path
then. Thanks!
>>
>> [...snip...]
>>
^ permalink raw reply
* Re: [PATCH v8 18/46] KVM: guest_memfd: Handle lru_add fbatch refcounts during conversion safety check
From: Ackerley Tng @ 2026-06-24 22:25 UTC (permalink / raw)
To: Sean Christopherson
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, tabba, willy,
wyihan, yan.y.zhao, forkloop, pratyush, suzuki.poulose,
aneesh.kumar, liam, Paolo Bonzini, 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: <ajwMYCSrPlxg-Fok@google.com>
Sean Christopherson <seanjc@google.com> writes:
> On Thu, Jun 18, 2026, Ackerley Tng wrote:
>> When checking if a guest_memfd folio is safe for conversion, its refcount
>> is examined. A folio may be present in a per-CPU lru_add fbatch, which
>> temporarily increases its refcount.
>
> Under what circumstances does this happen,
It happened 100% of the time in selftests. Perhaps it's because in the
selftests the pages are almost always freshly allocated and so the
lru_add fbatch isn't full yet? (and that the host isn't super busy so
lru_add fbatch doesn't get drained yet).
I've not tested without this beyond selftests.
I don't think we can depend on workloads to drain the lru_add fbatch?
> and what alternatives are there for
> userspace to work around the issue?
The thing is, the refcounts don't come with a label of who added the
refcount so we can't really return a different error for lru_add fbatch
presence. All folios get added to the lru_add fbatch even if they're
unevictable and eventually not participate in LRU.
We could make userspace try fadvise(POSIX_FADV_DONTNEED)? I think that
has other problems, and this kind of makes userspace have one more user
to guess. Userspace already needs to check if the page is pinned for
DMA, and if it's not pinned for DMA, userspace already needs to retry
because of other possible kernel users...
^ permalink raw reply
* Re: [PATCH v8 15/46] KVM: guest_memfd: Call arch invalidate hooks on conversion
From: Suzuki K Poulose @ 2026-06-24 22:15 UTC (permalink / raw)
To: Ackerley Tng, Sean Christopherson, Fuad Tabba
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,
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: <CAEvNRgGX3GkazCWM=6y9YLgn=YemXuG==Oo+L58cac1Fd86_TQ@mail.gmail.com>
On 24/06/2026 18:46, Ackerley Tng wrote:
> Sean Christopherson <seanjc@google.com> writes:
>
>> On Fri, Jun 19, 2026, Fuad Tabba wrote:
>>> 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.
>>
>> Crud. It may not be urgent for arm64, but it's urgent for other reasons that
>> I "can't" describe in detail at the moment, and even if that weren't the case, I
>> think we should clean things up now. More below.
>>
>>>> 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)
>>
>> Not your fault, but kvm_arch_gmem_invalidate() is badly misnamed. It's not
>> "invalidating" anything, it's much more of a "free" callback, as SNP uses it to
>> put physical pages back into a shared state when a maybe-private folio is freed.
>>
>> As Fuad points out, (ab)using that hook for the private=>shared conversion case
>> "works", but not broadly. And it makes the bad name worse, because it's called
>> from code that _is_ doing true invalidations. For pKVM, it may not even need to
>> do anything invalidation-like.
>>
>
> Thanks, I also didn't like the naming of kvm_gmem_invalidate(),
> especially when conversions also calls
> kvm_gmem_invalidate_{start,end}() and those do different things.
>
>> To avoid a conflict with patches that are going to have priority over this series,
>> to set the stage for arm64 support, and to avoid avoid bleeding vendor details
>> into guest_memfd, as if they are core guest_memfd behavior (only SNP needs the
>> "invalidation" on this specific transition), I think we should add an arch hook
>> to do conversions straightaway.
>>
>> Unless there's a clever option I'm missing, it'll mean adding yet another
>> HAVE_KVM_ARCH_GMEM_XXX flag? Hmm, especially because IIUC, arm64/pKVM doesn't
>> need a callback for this case, only the free_folio case.
>>
>>>> +{
>>>> + 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);
>>
>> E.g. instead make this something like this?
>>
>> kvm_gmem_set_pfn_attributes(...)
>>
>> Hrm, though that wastes folio lookups in the to_private case. So maybe just this,
>> assuming pKVM doesn't need to take additional action on conversions?
>>
>> if (!to_private)
>> kvm_gmem_make_shared(...)
>>
>> Actually, if we do that, then we don't need a separate arch hook, just a separate
>> config. It'll still bleed SNP details into guest_memfd, but it'll at least be
>> done in a way that's more explicitly arch specific (and it's no different than
>> what we already do for PREPARE...).
>>
>
> pKVM needs some arch guest_memfd lifecycle functions that
>
> + for conversion, doesn't do anything,
> + for teardown, resets page state (IIUC it'll be reset to
> PKVM_PAGE_OWNED (by the host))
>
> So I think we need different functions for those two stages in the
> lifecycle of a page with guest_memfd? What if we have
>
> CONFIG_HAVE_KVM_ARCH_GMEM_SET_PFN_ATTRIBUTES, which gates
>
> + kvm_gmem_should_set_pfn_attributes(attributes) and
> .gmem_should_set_pfn_attributes
> + kvm_gmem_set_pfn_attributes(start_pfn, end_pfn, attributes) and
> .gmem_set_pfn_attributes
>
> CONFIG_HAVE_KVM_ARCH_GMEM_TEARDOWN, which gates
>
> + kvm_gmem_teardown() and .gmem_teardown
>
> SNP:
>
> + .gmem_should_set_pfn_attributes = sev_gmem_should_set_pfn_attributes,
> and sev_gmem_should_set_pfn_attributes returns !is_private
> + Rename .gmem_invalidate and sev_gmem_invalidate to *set_pfn_attributes
> + .gmem_teardown = sev_gmem_set_pfn_attributes
>
> TDX:
>
> + Disable CONFIG_HAVE_KVM_ARCH_GMEM_SET_PFN_ATTRIBUTES
> + Disable CONFIG_HAVE_KVM_ARCH_GMEM_TEARDOWN
>
> pKVM:
>
> + Disable CONFIG_HAVE_KVM_ARCH_GMEM_SET_PFN_ATTRIBUTES
> + .gmem_teardown = pkvm_gmem_set_pfn_attributes
>
> Suzuki, does this work for ARM CCA?
Yep, that works for us. For CCA we would :
+ Disable CONFIG_HAVE_KVM_ARCH_GMEM_SET_PFN_ATTRIBUTES
+ Disable CONFIG_HAVE_KVM_ARCH_GMEM_TEARDOWN
In the future we might utilise the gmem_set_pfn_attributes call back.
Thanks
Suzuki
>
> This way,
>
> + The if (is_private) check doesn't leak SNP details into guest_memfd
> + .gmem_make_shared doesn't stick out without a .gmem_make_private
> + .gmem_set_pfn_attributes, .gmem_prepare and .gmem_teardown are aligned
> conceptually as lifecycle hooks
>
> + I think the private/shared check for prepare can also be folded into
> preparation.
> + Preparation perhaps doesn't need a should_prepare equivalent since
> there's no iteration and getting the gfn is just doing some math?
> + In another patch series?
>
>> E.g. this? There will still be a looming rename conflict, but that's easy enough
>> to handle.
>>
>> diff --git virt/kvm/guest_memfd.c virt/kvm/guest_memfd.c
>> index 9ce5be7843f2..8aead0abd788 100644
>> --- virt/kvm/guest_memfd.c
>> +++ virt/kvm/guest_memfd.c
>> @@ -648,8 +648,8 @@ 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)
>> +#ifdef CONFIG_KVM_ARCH_GMEM_FREE_ON_SHARED_CONVERSION
>> +static void kvm_gmem_make_shared(struct inode *inode, pgoff_t start, pgoff_t end)
>> {
>> struct folio_batch fbatch;
>> pgoff_t next = start;
>> @@ -681,7 +681,7 @@ static void kvm_gmem_invalidate(struct inode *inode, pgoff_t start, pgoff_t end)
>> }
>> }
>> #else
>> -static void kvm_gmem_invalidate(struct inode *inode, pgoff_t start, pgoff_t end) {}
>> +static void kvm_gmem_make_shared(struct inode *inode, pgoff_t start, pgoff_t end) { }
>> #endif
>>
>> static int __kvm_gmem_set_attributes(struct inode *inode, pgoff_t start,
>> @@ -729,7 +729,7 @@ 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);
>> + kvm_gmem_make_shared(inode, start, end);
>>
>> mas_store_prealloc(&mas, xa_mk_value(attrs));
^ permalink raw reply
* Re: [PATCH v12 07/12] static_call: Define EXPORT_STATIC_CALL_FOR_MODULES()
From: Sean Christopherson @ 2026-06-24 22:03 UTC (permalink / raw)
To: Pawan Gupta
Cc: x86, Jon Kohler, Nikolay Borisov, H. Peter Anvin, Josh Poimboeuf,
David Kaplan, Borislav Petkov, Dave Hansen, Peter Zijlstra,
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, KP Singh,
Jiri Olsa, David S. Miller, David Laight, Andy Lutomirski,
Thomas Gleixner, Ingo Molnar, David Ahern, Martin KaFai Lau,
Eduard Zingerman, Song Liu, Yonghong Song, John Fastabend,
Stanislav Fomichev, Hao Luo, Paolo Bonzini, Jonathan Corbet,
Jason Baron, Alice Ryhl, Steven Rostedt, Ard Biesheuvel,
Shuah Khan, linux-kernel, kvm, Asit Mallick, Tao Zhang, bpf,
netdev, linux-doc
In-Reply-To: <20260624214955.6kkivefeuapcocib@desk>
On Wed, Jun 24, 2026, Pawan Gupta wrote:
> On Wed, Jun 24, 2026 at 05:59:19AM -0700, Sean Christopherson wrote:
> > On Tue, Jun 23, 2026, Pawan Gupta wrote:
> > > There is EXPORT_STATIC_CALL_TRAMP() that hides the static key from all
> > > modules. But there is no equivalent of EXPORT_SYMBOL_FOR_MODULES() to
> > > restrict symbol visibility to only certain modules.
> > >
> > > Add EXPORT_STATIC_CALL_FOR_MODULES(name, mods) that wraps both the key and
> > > the trampoline with EXPORT_SYMBOL_FOR_MODULES(), allowing only a limited
> > > set of modules to see and update the static key.
> > >
> > > The immediate user is KVM, in the following commit.
> > >
> > > checkpatch reported below warnings with this change that I believe don't
> > > apply in this case:
> > >
> > > include/linux/static_call.h:219: WARNING: Non-declarative macros with multiple statements should be enclosed in a do - while loop
> > > include/linux/static_call.h:220: WARNING: EXPORT_SYMBOL(foo); should immediately follow its function/variable
> > >
> > > Suggested-by: Peter Zijlstra <peterz@infradead.org>
> > > Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
> > > ---
...
> > Drat, I forgot about this. Exporting static call trampolines for KVM came up in
> > another conversation[*]. I had already put together patches to effectively default
> > to exporting only the trampoline, and also to deduplicate this code so that the
> > CONFIG_HAVE_STATIC_CALL_INLINE=y / CONFIG_HAVE_STATIC_CALL=y / CONFIG_HAVE_STATIC_CALL=n
> > implementations don't need to copy+paste the same lines of code.
> >
> > The attached patches touch a lot more code, and will conflict mightily with KVM
> > changes I want to land in 7.3 (more use of a static_call in KVM). But if we get
> > them applied (to tip tree) shortly after 7.2-rc1 and provide a topic branch/tag,
> > then there shouldn't be too much juggling needed?
> >
> > If we want to go with the more aggressive cleanup, I'll formally post the patches.
> >
> > [*] https://lore.kernel.org/all/ahhoDGUz39KSGZ6o@google.com
>
> Thanks for the context.
>
> Earlier making the key ro-after-init came up as an option in a thread with
> Peter. Does it look like a good option to you?
No, it won't work for KVM. kvm.ko (owner of the keys) updates the keys only when
a vendor module (kvm-intel.ko or kvm-amd.ko) is loaded, and updates keys *every*
time a vendor module is loaded. So for KVM, the static calls need to be __read_mostly,
not __ro_after_init.
> diff --git a/include/linux/static_call.h b/include/linux/static_call.h
> index b610afd1ed55..ea56da8fb446 100644
> --- a/include/linux/static_call.h
> +++ b/include/linux/static_call.h
> @@ -200,6 +200,14 @@ extern long __static_call_return0(void);
> }; \
> ARCH_DEFINE_STATIC_CALL_NULL_TRAMP(name)
>
> +#define DEFINE_STATIC_CALL_NULL_RO_AFTER_INIT(name, _func) \
> + DECLARE_STATIC_CALL(name, _func); \
> + struct static_call_key STATIC_CALL_KEY(name) __ro_after_init = {\
> + .func = _func, \
> + .type = 1, \
> + }; \
> + ARCH_DEFINE_STATIC_CALL_NULL_TRAMP(name)
> +
> #define DEFINE_STATIC_CALL_RET0(name, _func) \
> DECLARE_STATIC_CALL(name, _func); \
> struct static_call_key STATIC_CALL_KEY(name) = { \
^ permalink raw reply
* Re: [PATCH v12 07/12] static_call: Define EXPORT_STATIC_CALL_FOR_MODULES()
From: Pawan Gupta @ 2026-06-24 21:49 UTC (permalink / raw)
To: Sean Christopherson
Cc: x86, Jon Kohler, Nikolay Borisov, H. Peter Anvin, Josh Poimboeuf,
David Kaplan, Borislav Petkov, Dave Hansen, Peter Zijlstra,
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, KP Singh,
Jiri Olsa, David S. Miller, David Laight, Andy Lutomirski,
Thomas Gleixner, Ingo Molnar, David Ahern, Martin KaFai Lau,
Eduard Zingerman, Song Liu, Yonghong Song, John Fastabend,
Stanislav Fomichev, Hao Luo, Paolo Bonzini, Jonathan Corbet,
Jason Baron, Alice Ryhl, Steven Rostedt, Ard Biesheuvel,
Shuah Khan, linux-kernel, kvm, Asit Mallick, Tao Zhang, bpf,
netdev, linux-doc
In-Reply-To: <ajvUp_kPJBRZ7k_p@google.com>
On Wed, Jun 24, 2026 at 05:59:19AM -0700, Sean Christopherson wrote:
> On Tue, Jun 23, 2026, Pawan Gupta wrote:
> > There is EXPORT_STATIC_CALL_TRAMP() that hides the static key from all
> > modules. But there is no equivalent of EXPORT_SYMBOL_FOR_MODULES() to
> > restrict symbol visibility to only certain modules.
> >
> > Add EXPORT_STATIC_CALL_FOR_MODULES(name, mods) that wraps both the key and
> > the trampoline with EXPORT_SYMBOL_FOR_MODULES(), allowing only a limited
> > set of modules to see and update the static key.
> >
> > The immediate user is KVM, in the following commit.
> >
> > checkpatch reported below warnings with this change that I believe don't
> > apply in this case:
> >
> > include/linux/static_call.h:219: WARNING: Non-declarative macros with multiple statements should be enclosed in a do - while loop
> > include/linux/static_call.h:220: WARNING: EXPORT_SYMBOL(foo); should immediately follow its function/variable
> >
> > Suggested-by: Peter Zijlstra <peterz@infradead.org>
> > Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
> > ---
> > include/linux/static_call.h | 8 ++++++++
> > 1 file changed, 8 insertions(+)
> >
> > diff --git a/include/linux/static_call.h b/include/linux/static_call.h
> > index 78a77a4ae0ea..b610afd1ed55 100644
> > --- a/include/linux/static_call.h
> > +++ b/include/linux/static_call.h
> > @@ -216,6 +216,9 @@ extern long __static_call_return0(void);
> > #define EXPORT_STATIC_CALL_GPL(name) \
> > EXPORT_SYMBOL_GPL(STATIC_CALL_KEY(name)); \
> > EXPORT_SYMBOL_GPL(STATIC_CALL_TRAMP(name))
> > +#define EXPORT_STATIC_CALL_FOR_MODULES(name, mods) \
> > + EXPORT_SYMBOL_FOR_MODULES(STATIC_CALL_KEY(name), mods); \
> > + EXPORT_SYMBOL_FOR_MODULES(STATIC_CALL_TRAMP(name), mods)
> >
> > /* Leave the key unexported, so modules can't change static call targets: */
> > #define EXPORT_STATIC_CALL_TRAMP(name) \
> > @@ -276,6 +279,9 @@ extern long __static_call_return0(void);
> > #define EXPORT_STATIC_CALL_GPL(name) \
> > EXPORT_SYMBOL_GPL(STATIC_CALL_KEY(name)); \
> > EXPORT_SYMBOL_GPL(STATIC_CALL_TRAMP(name))
> > +#define EXPORT_STATIC_CALL_FOR_MODULES(name, mods) \
> > + EXPORT_SYMBOL_FOR_MODULES(STATIC_CALL_KEY(name), mods); \
> > + EXPORT_SYMBOL_FOR_MODULES(STATIC_CALL_TRAMP(name), mods)
> >
> > /* Leave the key unexported, so modules can't change static call targets: */
> > #define EXPORT_STATIC_CALL_TRAMP(name) \
> > @@ -346,6 +352,8 @@ static inline int static_call_text_reserved(void *start, void *end)
> >
> > #define EXPORT_STATIC_CALL(name) EXPORT_SYMBOL(STATIC_CALL_KEY(name))
> > #define EXPORT_STATIC_CALL_GPL(name) EXPORT_SYMBOL_GPL(STATIC_CALL_KEY(name))
> > +#define EXPORT_STATIC_CALL_FOR_MODULES(name, mods) \
> > + EXPORT_SYMBOL_FOR_MODULES(STATIC_CALL_KEY(name), mods)
> >
> > #endif /* CONFIG_HAVE_STATIC_CALL */
>
> Drat, I forgot about this. Exporting static call trampolines for KVM came up in
> another conversation[*]. I had already put together patches to effectively default
> to exporting only the trampoline, and also to deduplicate this code so that the
> CONFIG_HAVE_STATIC_CALL_INLINE=y / CONFIG_HAVE_STATIC_CALL=y / CONFIG_HAVE_STATIC_CALL=n
> implementations don't need to copy+paste the same lines of code.
>
> The attached patches touch a lot more code, and will conflict mightily with KVM
> changes I want to land in 7.3 (more use of a static_call in KVM). But if we get
> them applied (to tip tree) shortly after 7.2-rc1 and provide a topic branch/tag,
> then there shouldn't be too much juggling needed?
>
> If we want to go with the more aggressive cleanup, I'll formally post the patches.
>
> [*] https://lore.kernel.org/all/ahhoDGUz39KSGZ6o@google.com
Thanks for the context.
Earlier making the key ro-after-init came up as an option in a thread with
Peter. Does it look like a good option to you?
diff --git a/include/linux/static_call.h b/include/linux/static_call.h
index b610afd1ed55..ea56da8fb446 100644
--- a/include/linux/static_call.h
+++ b/include/linux/static_call.h
@@ -200,6 +200,14 @@ extern long __static_call_return0(void);
}; \
ARCH_DEFINE_STATIC_CALL_NULL_TRAMP(name)
+#define DEFINE_STATIC_CALL_NULL_RO_AFTER_INIT(name, _func) \
+ DECLARE_STATIC_CALL(name, _func); \
+ struct static_call_key STATIC_CALL_KEY(name) __ro_after_init = {\
+ .func = _func, \
+ .type = 1, \
+ }; \
+ ARCH_DEFINE_STATIC_CALL_NULL_TRAMP(name)
+
#define DEFINE_STATIC_CALL_RET0(name, _func) \
DECLARE_STATIC_CALL(name, _func); \
struct static_call_key STATIC_CALL_KEY(name) = { \
^ permalink raw reply related
* Re: [PATCH v8 13/46] KVM: guest_memfd: Add base support for KVM_SET_MEMORY_ATTRIBUTES2
From: Ackerley Tng @ 2026-06-24 21:10 UTC (permalink / raw)
To: Binbin Wu
Cc: aik, andrew.jones, 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, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <ede86ac4-d560-49a6-82d6-b33ac5fc9355@linux.intel.com>
Binbin Wu <binbin.wu@linux.intel.com> writes:
> On 6/19/2026 8:31 AM, Ackerley Tng via B4 Relay 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>
>
> s/Christoperson /Christopherson
>
Thanks!
>> Reviewed-by: Fuad Tabba <tabba@google.com>
>> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
>> ---
>> 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/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
>
> What's this?
> This config is gone.
>
I'm surprised this compiles... I'll fix it, thanks!
>> bool
>>
^ permalink raw reply
* Re: [PATCH v8 13/46] KVM: guest_memfd: Add base support for KVM_SET_MEMORY_ATTRIBUTES2
From: Ackerley Tng @ 2026-06-24 21:03 UTC (permalink / raw)
To: Fuad Tabba, Sean Christopherson
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, 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+EHjTwLPCvZJgPv=8u3pgp+kwEwQbsXn_13FL3xUbJ7HRfXzw@mail.gmail.com>
Fuad Tabba <fuad.tabba@linux.dev> writes:
>
> [...snip...]
>
>> >
>> > 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/.
I took Sean's patches (off-list) and tried to combine it onto my
existing state. (I'm using b4 [1] to manage these series and I didn't
know I had to manually update the base-commit. Will try again next
revision.
[1] https://b4.docs.kernel.org/en/latest/
>>
>> Ya, Ackerley used a slightly older kvm/next to send the patches. I at least was
>> testing against kvm-x86/next, which does have the rename.
>>
>> Other than noting that this should be applied against the current kvm/next, I
>> don't think there's anything else to be done?
Should I base v9 on kvm/next, or kvm-x86/next?
>
> Agree. Sorry, didn't mean to be nit-picky, but this really threw me off :)
>
> Cheers,
> /fuad
^ permalink raw reply
* Re: [PATCH] Documentation: dev-tools: scripts/container prefers Podman
From: Guillaume Tucker @ 2026-06-24 21:02 UTC (permalink / raw)
To: Coiby Xu, linux-doc
Cc: Jonathan Corbet, Shuah Khan, open list:DOCUMENTATION PROCESS,
open list
In-Reply-To: <20260624013850.1853171-1-coiby.xu@gmail.com>
Hi Coiby,
On 24/06/2026 03:38, Coiby Xu wrote:
> Obviously scripts/container prefers Podman over Docker. Putting podman
> before docker also makes it consistent with following parts of the doc
> and the help text of the tool.
>
> Signed-off-by: Coiby Xu <coiby.xu@gmail.com>
> ---
> Documentation/dev-tools/container.rst | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/dev-tools/container.rst b/Documentation/dev-tools/container.rst
> index 452415b64662..9e23f79d5ae1 100644
> --- a/Documentation/dev-tools/container.rst
> +++ b/Documentation/dev-tools/container.rst
> @@ -40,7 +40,7 @@ Available options:
>
> ``-r, --runtime RUNTIME``
>
> - Container runtime name. Supported runtimes: ``docker``, ``podman``.
> + Container runtime name. Supported runtimes: ``podman``, ``docker``.
>
> If not specified, the first one found on the system will be used
> i.e. Podman if present, otherwise Docker.
> @@ -75,8 +75,8 @@ working directory and adjust the user and group id as needed.
>
> The container image which would typically include a compiler toolchain is
> provided by the user and selected via the ``-i`` option. The container runtime
> -can be selected with the ``-r`` option, which can be either ``docker`` or
> -``podman``. If none is specified, the first one found on the system will be
> +can be selected with the ``-r`` option, which can be either ``podman`` or
> +``docker``. If none is specified, the first one found on the system will be
> used while giving priority to Podman. Support for other runtimes may be added
> later depending on their popularity among users.
>
It's a very subtle tweak but it does help avoid some confusion.
Reviewed-by: Guillaume Tucker <gtucker@gtucker.io>
Thanks,
Guillaume
^ permalink raw reply
* Re: [PATCH v2 0/2] cgroup/cpuset: Miscellaneous fixes and cleanups
From: Waiman Long @ 2026-06-24 20:55 UTC (permalink / raw)
To: Tejun Heo
Cc: Johannes Weiner, Michal Koutný, Ridong Chen, Jonathan Corbet,
Shuah Khan, cgroups, linux-kernel, linux-doc, linux-kselftest
In-Reply-To: <038bfbbc34714676b7a672b7f748aee4@kernel.org>
On 6/24/26 3:47 PM, Tejun Heo wrote:
>> Waiman Long (2):
>> cgroup/cpuset: Avoid unnecessary cpus & mems update in
>> cpuset_hotplug_update_tasks()
>> cgroup/cpuset: Rebind/migrate mm only for threadgroup leader in
>> cpuset_update_tasks_nodemask()
> Applied 1-2 to cgroup/for-7.3. I folded in a few minor fixups: a
> changelog typo, the compute_effective_nodemask() kerneldoc parameter
> name (new_cpus to new_mems), and the comment and doc grammar nits Manuel
> noted. Also added Ridong's Reviewed-by to patch 1.
Thanks for the fixups.
Cheers,
Longman
^ permalink raw reply
* Re: [PATCH v8 10/46] KVM: guest_memfd: Wire up core private/shared attribute interfaces
From: Ackerley Tng @ 2026-06-24 20:44 UTC (permalink / raw)
To: Binbin Wu
Cc: aik, andrew.jones, 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, kvm, linux-kernel,
linux-trace-kernel, linux-doc, linux-kselftest, linux-mm,
linux-coco
In-Reply-To: <2ef455c3-a3f5-4ba1-86ea-b96416d163ce@linux.intel.com>
Binbin Wu <binbin.wu@linux.intel.com> writes:
> On 6/19/2026 8:31 AM, Ackerley Tng via B4 Relay wrote:
>
> [...]
>
>> 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;
>> + }
>
> Patch 1 noted that "Ensuring every index is represented in the maple tree at all times".
> So I think the queried range should not be a hole in the maple tree.
> However, there is a inconsistency: in patch 1 kvm_gmem_get_attributes() explicitly
> checks for holes, but this patch does not.
>
>> + return true;
>> +}
>>
With Sean's suggestion for patch 1, I'll update this one to default to
the "init" state if xa_to_value(entry) is NULL.
Thanks!
^ permalink raw reply
* [jlayton:nfsd-testing 3/3] htmldocs: Warning: fs/nfsd/nfs4proc.c references a file that doesn't exist: Documentation/atomic_bitops.rst
From: kernel test robot @ 2026-06-24 20:14 UTC (permalink / raw)
Cc: oe-kbuild-all, Jeff Layton, linux-doc
tree: https://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux.git nfsd-testing
head: a6bb4945e70c1078941fda53314ed0eb6198b724
commit: a6bb4945e70c1078941fda53314ed0eb6198b724 [3/3] nfsd: fix UAF in async copy cancel and shutdown
compiler: clang version 22.1.8 (https://github.com/llvm/llvm-project ca7933e47d3a3451d81e72ac174dcb5aa28b59d1)
docutils: docutils (Docutils 0.21.2, Python 3.13.5, on linux)
reproduce: (https://download.01.org/0day-ci/archive/20260624/202606242223.Mks9jBen-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202606242223.Mks9jBen-lkp@intel.com/
All warnings (new ones prefixed by >>):
Warning: Documentation/translations/zh_CN/scsi/scsi_mid_low_api.rst references a file that doesn't exist: Documentation/Configure.help
Warning: MAINTAINERS references a file that doesn't exist: Documentation/ABI/testing/sysfs-platform-ayaneo
Warning: MAINTAINERS references a file that doesn't exist: Documentation/devicetree/bindings/display/bridge/megachips-stdpxxxx-ge-b850v3-fw.txt
Warning: arch/powerpc/sysdev/mpic.c references a file that doesn't exist: Documentation/devicetree/bindings/powerpc/fsl/mpic.txt
Warning: drivers/net/ethernet/smsc/Kconfig references a file that doesn't exist: file:Documentation/networking/device_drivers/ethernet/smsc/smc9.rst
>> Warning: fs/nfsd/nfs4proc.c references a file that doesn't exist: Documentation/atomic_bitops.rst
Warning: rust/kernel/sync/atomic/ordering.rs references a file that doesn't exist: srctree/tools/memory-model/Documentation/explanation.txt
Warning: tools/docs/documentation-file-ref-check references a file that doesn't exist: Documentation/virtual/lguest/lguest.c
Warning: tools/docs/documentation-file-ref-check references a file that doesn't exist: m,\b(\S*)(Documentation/[A-Za-z0-9
Warning: tools/docs/documentation-file-ref-check references a file that doesn't exist: Documentation/devicetree/dt-object-internal.txt
Warning: tools/docs/documentation-file-ref-check references a file that doesn't exist: m,^Documentation/scheduler/sched-pelt
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply
* Re: [PATCH] Docs/admin-guide/cgroup-v2: fix memory.stat doc details
From: Tejun Heo @ 2026-06-24 20:07 UTC (permalink / raw)
To: Doehyun Baek
Cc: Jonathan Corbet, Johannes Weiner, Michal Koutný,
Andrew Morton, Shakeel Butt, Roman Gushchin, Yosry Ahmed,
Nhat Pham, cgroups, linux-doc, linux-kernel
In-Reply-To: <20260620122751.388770-1-doehyunbaek@gmail.com>
Applied to cgroup/for-7.2-fixes.
Thanks.
--
tejun
^ permalink raw reply
* Re: [PATCH v8 32/46] KVM: selftests: Test conversion flow when INIT_SHARED
From: Fuad Tabba @ 2026-06-24 19:55 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-v8-32-9d2959357853@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>
>
> Add a test case to verify that conversions between private and shared
> memory work correctly when the memory is initially created as shared.
>
> 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
> ---
> .../testing/selftests/kvm/x86/guest_memfd_conversions_test.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
> index 8e09e241723e5..5b070d3374eae 100644
> --- a/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
> +++ b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
> @@ -95,6 +95,12 @@ static void __gmem_conversions_##test(test_data_t *t, int nr_pages) \
> #define GMEM_CONVERSION_TEST_INIT_PRIVATE(test) \
> __GMEM_CONVERSION_TEST_INIT_PRIVATE(test, 1)
>
> +#define __GMEM_CONVERSION_TEST_INIT_SHARED(test, __nr_pages) \
> + GMEM_CONVERSION_TEST(test, __nr_pages, GUEST_MEMFD_FLAG_INIT_SHARED)
> +
> +#define GMEM_CONVERSION_TEST_INIT_SHARED(test) \
> + __GMEM_CONVERSION_TEST_INIT_SHARED(test, 1)
> +
> struct guest_check_data {
> void *mem;
> char expected_val;
> @@ -186,6 +192,12 @@ GMEM_CONVERSION_TEST_INIT_PRIVATE(init_private)
> test_convert_to_private(t, 0, 'C', 'E');
> }
>
> +GMEM_CONVERSION_TEST_INIT_SHARED(init_shared)
> +{
> + test_shared(t, 0, 0, 'A', 'B');
> + test_convert_to_private(t, 0, 'B', 'C');
> + test_convert_to_shared(t, 0, 'C', 'D', 'E');
> +}
>
> int main(int argc, char *argv[])
> {
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v2 0/2] cgroup/cpuset: Miscellaneous fixes and cleanups
From: Tejun Heo @ 2026-06-24 19:47 UTC (permalink / raw)
To: Waiman Long
Cc: Johannes Weiner, Michal Koutný, Ridong Chen, Jonathan Corbet,
Shuah Khan, cgroups, linux-kernel, linux-doc, linux-kselftest
In-Reply-To: <20260623230413.1984188-1-longman@redhat.com>
> Waiman Long (2):
> cgroup/cpuset: Avoid unnecessary cpus & mems update in
> cpuset_hotplug_update_tasks()
> cgroup/cpuset: Rebind/migrate mm only for threadgroup leader in
> cpuset_update_tasks_nodemask()
Applied 1-2 to cgroup/for-7.3. I folded in a few minor fixups: a
changelog typo, the compute_effective_nodemask() kerneldoc parameter
name (new_cpus to new_mems), and the comment and doc grammar nits Manuel
noted. Also added Ridong's Reviewed-by to patch 1.
Thanks.
--
tejun
^ permalink raw reply
* Re: [PATCH v8 31/46] KVM: selftests: Test basic single-page conversion flow
From: Fuad Tabba @ 2026-06-24 19:45 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-v8-31-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:32, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Ackerley Tng <ackerleytng@google.com>
>
> Add a selftest for the guest_memfd memory attribute conversion ioctls.
> The test starts the guest_memfd as all-private (the default state), and
> verifies the basic flow of converting a single page to shared and then back
> to private.
>
> Add infrastructure that supports extensions to other conversion flow
> tests. This infrastructure will be used in upcoming patches for other
> conversion tests.
>
> Add test as an x86-specific test since guest_memfd's testing
> vehicle (KVM_X86_SW_PROTECTED_VM) is x86-specific.
>
> 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
> ---
> tools/testing/selftests/kvm/Makefile.kvm | 1 +
> .../kvm/x86/guest_memfd_conversions_test.c | 199 +++++++++++++++++++++
> 2 files changed, 200 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
> index 4ace12606e937..b0e64a6dde21a 100644
> --- a/tools/testing/selftests/kvm/Makefile.kvm
> +++ b/tools/testing/selftests/kvm/Makefile.kvm
> @@ -152,6 +152,7 @@ TEST_GEN_PROGS_x86 += x86/max_vcpuid_cap_test
> TEST_GEN_PROGS_x86 += x86/triple_fault_event_test
> TEST_GEN_PROGS_x86 += x86/recalc_apic_map_test
> TEST_GEN_PROGS_x86 += x86/aperfmperf_test
> +TEST_GEN_PROGS_x86 += x86/guest_memfd_conversions_test
> TEST_GEN_PROGS_x86 += access_tracking_perf_test
> TEST_GEN_PROGS_x86 += coalesced_io_test
> TEST_GEN_PROGS_x86 += dirty_log_perf_test
> diff --git a/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
> new file mode 100644
> index 0000000000000..8e09e241723e5
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/x86/guest_memfd_conversions_test.c
> @@ -0,0 +1,199 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2024, Google LLC.
> + */
> +#include <sys/mman.h>
> +#include <unistd.h>
> +
> +#include <linux/align.h>
> +#include <linux/kvm.h>
> +#include <linux/sizes.h>
> +
> +#include "kvm_util.h"
> +#include "kselftest_harness.h"
> +#include "test_util.h"
> +#include "ucall_common.h"
> +
> +FIXTURE(gmem_conversions) {
> + struct kvm_vcpu *vcpu;
> + int gmem_fd;
> + /* HVA of the first byte of the memory mmap()-ed from gmem_fd. */
> + char *mem;
> +};
> +
> +typedef FIXTURE_DATA(gmem_conversions) test_data_t;
> +
> +FIXTURE_SETUP(gmem_conversions) { }
> +
> +static size_t page_size;
> +
> +static void guest_do_rmw(void);
> +#define GUEST_MEMFD_SHARING_TEST_GVA 0x90000000ULL
> +
> +/*
> + * Defer setup until the individual test is invoked so that tests can specify
> + * the number of pages and flags for the guest_memfd instance.
> + */
> +static void gmem_conversions_do_setup(test_data_t *t, int nr_pages,
> + int gmem_flags)
> +{
> + const struct vm_shape shape = {
> + .mode = VM_MODE_DEFAULT,
> + .type = KVM_X86_SW_PROTECTED_VM,
> + };
> + /*
> + * Use high GPA above APIC_DEFAULT_PHYS_BASE to avoid clashing with
> + * APIC_DEFAULT_PHYS_BASE.
> + */
> + const gpa_t gpa = SZ_4G;
> + const u32 slot = 1;
> + struct kvm_vm *vm;
> +
> + vm = __vm_create_shape_with_one_vcpu(shape, &t->vcpu, nr_pages, guest_do_rmw);
> +
> + vm_mem_add(vm, VM_MEM_SRC_SHMEM, gpa, slot, nr_pages,
> + KVM_MEM_GUEST_MEMFD, -1, 0, gmem_flags);
> +
> + t->gmem_fd = kvm_slot_to_fd(vm, slot);
> + t->mem = addr_gpa2hva(vm, gpa);
> + virt_map(vm, GUEST_MEMFD_SHARING_TEST_GVA, gpa, nr_pages);
> +}
> +
> +static void gmem_conversions_do_teardown(test_data_t *t)
> +{
> + /* No need to close gmem_fd, it's owned by the VM structure. */
> + kvm_vm_free(t->vcpu->vm);
> +}
> +
> +FIXTURE_TEARDOWN(gmem_conversions)
> +{
> + gmem_conversions_do_teardown(self);
> +}
> +
> +/*
> + * In these test definition macros, __nr_pages and nr_pages is used to set up
> + * the total number of pages in the guest_memfd under test. This will be
> + * available in the test definitions as nr_pages.
> + */
> +
> +#define __GMEM_CONVERSION_TEST(test, __nr_pages, flags) \
> +static void __gmem_conversions_##test(test_data_t *t, int nr_pages); \
> + \
> +TEST_F(gmem_conversions, test) \
> +{ \
> + gmem_conversions_do_setup(self, __nr_pages, flags); \
> + __gmem_conversions_##test(self, __nr_pages); \
> +} \
> +static void __gmem_conversions_##test(test_data_t *t, int nr_pages) \
> +
> +#define GMEM_CONVERSION_TEST(test, __nr_pages, flags) \
> + __GMEM_CONVERSION_TEST(test, __nr_pages, (flags) | GUEST_MEMFD_FLAG_MMAP)
> +
> +#define __GMEM_CONVERSION_TEST_INIT_PRIVATE(test, __nr_pages) \
> + GMEM_CONVERSION_TEST(test, __nr_pages, 0)
> +
> +#define GMEM_CONVERSION_TEST_INIT_PRIVATE(test) \
> + __GMEM_CONVERSION_TEST_INIT_PRIVATE(test, 1)
> +
> +struct guest_check_data {
> + void *mem;
> + char expected_val;
> + char write_val;
> +};
> +static struct guest_check_data guest_data;
> +
> +static void guest_do_rmw(void)
> +{
> + for (;;) {
> + char *mem = READ_ONCE(guest_data.mem);
> +
> + GUEST_ASSERT_EQ(READ_ONCE(*mem), READ_ONCE(guest_data.expected_val));
> + WRITE_ONCE(*mem, READ_ONCE(guest_data.write_val));
> +
> + GUEST_SYNC(0);
> + }
> +}
> +
> +static void run_guest_do_rmw(struct kvm_vcpu *vcpu, u64 pgoff,
> + char expected_val, char write_val)
> +{
> + struct ucall uc;
> + int r;
> +
> + guest_data.mem = (void *)GUEST_MEMFD_SHARING_TEST_GVA + pgoff * page_size;
> + guest_data.expected_val = expected_val;
> + guest_data.write_val = write_val;
> + sync_global_to_guest(vcpu->vm, guest_data);
> +
> + do {
> + r = __vcpu_run(vcpu);
> + } while (r == -1 && errno == EINTR);
> +
> + TEST_ASSERT_EQ(r, 0);
> +
> + switch (get_ucall(vcpu, &uc)) {
> + case UCALL_ABORT:
> + REPORT_GUEST_ASSERT(uc);
> + case UCALL_SYNC:
> + break;
> + default:
> + TEST_FAIL("Unexpected ucall %lu", uc.cmd);
> + }
> +}
> +
> +static void host_do_rmw(char *mem, u64 pgoff, char expected_val,
> + char write_val)
> +{
> + TEST_ASSERT_EQ(READ_ONCE(mem[pgoff * page_size]), expected_val);
> + WRITE_ONCE(mem[pgoff * page_size], write_val);
> +}
> +
> +static void test_private(test_data_t *t, u64 pgoff, char starting_val,
> + char write_val)
> +{
> + TEST_EXPECT_SIGBUS(WRITE_ONCE(t->mem[pgoff * page_size], write_val));
> + run_guest_do_rmw(t->vcpu, pgoff, starting_val, write_val);
> + TEST_EXPECT_SIGBUS(READ_ONCE(t->mem[pgoff * page_size]));
> +}
> +
> +static void test_convert_to_private(test_data_t *t, u64 pgoff,
> + char starting_val, char write_val)
> +{
> + gmem_set_private(t->gmem_fd, pgoff * page_size, page_size);
> + test_private(t, pgoff, starting_val, write_val);
> +}
> +
> +static void test_shared(test_data_t *t, u64 pgoff, char starting_val,
> + char host_write_val, char write_val)
> +{
> + host_do_rmw(t->mem, pgoff, starting_val, host_write_val);
> + run_guest_do_rmw(t->vcpu, pgoff, host_write_val, write_val);
> + TEST_ASSERT_EQ(READ_ONCE(t->mem[pgoff * page_size]), write_val);
> +}
> +
> +static void test_convert_to_shared(test_data_t *t, u64 pgoff,
> + char starting_val, char host_write_val,
> + char write_val)
> +{
> + gmem_set_shared(t->gmem_fd, pgoff * page_size, page_size);
> + test_shared(t, pgoff, starting_val, host_write_val, write_val);
> +}
> +
> +GMEM_CONVERSION_TEST_INIT_PRIVATE(init_private)
> +{
> + test_private(t, 0, 0, 'A');
> + test_convert_to_shared(t, 0, 'A', 'B', 'C');
> + test_convert_to_private(t, 0, 'C', 'E');
> +}
> +
> +
> +int main(int argc, char *argv[])
> +{
> + TEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_SW_PROTECTED_VM));
> + TEST_REQUIRE(kvm_check_cap(KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES) &
> + KVM_MEMORY_ATTRIBUTE_PRIVATE);
> +
> + page_size = getpagesize();
> +
> + return test_harness_run(argc, argv);
> +}
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v8 30/46] KVM: selftests: Add helpers for calling ioctls on guest_memfd
From: Fuad Tabba @ 2026-06-24 19:26 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-v8-30-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:32, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Sean Christopherson <seanjc@google.com>
>
> Add helper functions to kvm_util.h to support calling ioctls, specifically
> KVM_SET_MEMORY_ATTRIBUTES2, on a guest_memfd file descriptor.
>
> Introduce gmem_ioctl() and __gmem_ioctl() macros, modeled after the
> existing vm_ioctl() helpers, to provide a standard way to call ioctls
> on a guest_memfd.
>
> Add gmem_set_memory_attributes() and its derivatives (gmem_set_private(),
> gmem_set_shared()) to set memory attributes on a guest_memfd region.
> Also provide "__" variants that return the ioctl error code instead of
> aborting the test. These helpers will be used by upcoming guest_memfd
> tests.
>
> To avoid code duplication, factor out the check for supported memory
> attributes into a new macro, TEST_ASSERT_SUPPORTED_ATTRIBUTES, and use
> it in both the existing vm_set_memory_attributes() and the new
> gmem_set_memory_attributes() helpers.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Cheers,
/fuad
> ---
> tools/testing/selftests/kvm/include/kvm_util.h | 94 +++++++++++++++++++++++---
> 1 file changed, 86 insertions(+), 8 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
> index 0cacf3698b259..323d06b5699ec 100644
> --- a/tools/testing/selftests/kvm/include/kvm_util.h
> +++ b/tools/testing/selftests/kvm/include/kvm_util.h
> @@ -392,6 +392,16 @@ static __always_inline void static_assert_is_vcpu(struct kvm_vcpu *vcpu) { }
> __TEST_ASSERT_VM_VCPU_IOCTL(!ret, #cmd, ret, (vcpu)->vm); \
> })
>
> +#define __gmem_ioctl(gmem_fd, cmd, arg) \
> + kvm_do_ioctl(gmem_fd, cmd, arg)
> +
> +#define gmem_ioctl(gmem_fd, cmd, arg) \
> +({ \
> + int ret = __gmem_ioctl(gmem_fd, cmd, arg); \
> + \
> + TEST_ASSERT(!ret, __KVM_IOCTL_ERROR(#cmd, ret)); \
> +})
> +
> /*
> * Looks up and returns the value corresponding to the capability
> * (KVM_CAP_*) given by cap.
> @@ -418,8 +428,16 @@ static inline void vm_enable_cap(struct kvm_vm *vm, u32 cap, u64 arg0)
> vm_ioctl(vm, KVM_ENABLE_CAP, &enable_cap);
> }
>
> +/*
> + * KVM_SET_MEMORY_ATTRIBUTES{,2} overwrites _all_ attributes. These
> + * flows need significant enhancements to support multiple attributes.
> + */
> +#define TEST_ASSERT_SUPPORTED_ATTRIBUTES(attributes) \
> + TEST_ASSERT(!(attributes) || (attributes) == KVM_MEMORY_ATTRIBUTE_PRIVATE, \
> + "Update me to support multiple attributes!")
> +
> static inline void vm_set_memory_attributes(struct kvm_vm *vm, gpa_t gpa,
> - u64 size, u64 attributes)
> + size_t size, u64 attributes)
> {
> struct kvm_memory_attributes attr = {
> .attributes = attributes,
> @@ -428,17 +446,11 @@ static inline void vm_set_memory_attributes(struct kvm_vm *vm, gpa_t gpa,
> .flags = 0,
> };
>
> - /*
> - * KVM_SET_MEMORY_ATTRIBUTES overwrites _all_ attributes. These flows
> - * need significant enhancements to support multiple attributes.
> - */
> - TEST_ASSERT(!attributes || attributes == KVM_MEMORY_ATTRIBUTE_PRIVATE,
> - "Update me to support multiple attributes!");
> + TEST_ASSERT_SUPPORTED_ATTRIBUTES(attributes);
>
> vm_ioctl(vm, KVM_SET_MEMORY_ATTRIBUTES, &attr);
> }
>
> -
> static inline void vm_mem_set_private(struct kvm_vm *vm, gpa_t gpa,
> u64 size)
> {
> @@ -451,6 +463,72 @@ static inline void vm_mem_set_shared(struct kvm_vm *vm, gpa_t gpa,
> vm_set_memory_attributes(vm, gpa, size, 0);
> }
>
> +static inline int __gmem_set_memory_attributes(int fd, u64 offset,
> + size_t size, u64 attributes,
> + u64 *error_offset)
> +{
> + struct kvm_memory_attributes2 attr = {
> + .attributes = attributes,
> + .offset = offset,
> + .size = size,
> + .flags = 0,
> + .error_offset = 0,
> + };
> + int r;
> +
> + r = __gmem_ioctl(fd, KVM_SET_MEMORY_ATTRIBUTES2, &attr);
> +
> + /* Copy error_offset regardless of r so caller can check. */
> + if (error_offset)
> + *error_offset = attr.error_offset;
> +
> + return r;
> +}
> +
> +static inline int __gmem_set_private(int fd, u64 offset, size_t size,
> + u64 *error_offset)
> +{
> + return __gmem_set_memory_attributes(fd, offset, size,
> + KVM_MEMORY_ATTRIBUTE_PRIVATE,
> + error_offset);
> +}
> +
> +static inline int __gmem_set_shared(int fd, u64 offset, size_t size,
> + u64 *error_offset)
> +{
> + return __gmem_set_memory_attributes(fd, offset, size, 0,
> + error_offset);
> +}
> +
> +static inline void gmem_set_memory_attributes(int fd, u64 offset,
> + size_t size, u64 attributes)
> +{
> + struct kvm_memory_attributes2 attr = {
> + .attributes = attributes,
> + .offset = offset,
> + .size = size,
> + .flags = 0,
> + };
> +
> + TEST_ASSERT_SUPPORTED_ATTRIBUTES(attributes);
> +
> + __TEST_REQUIRE(kvm_check_cap(KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES) > 0,
> + "No valid attributes for guest_memfd ioctl!");
> +
> + gmem_ioctl(fd, KVM_SET_MEMORY_ATTRIBUTES2, &attr);
> +}
> +
> +static inline void gmem_set_private(int fd, u64 offset, size_t size)
> +{
> + gmem_set_memory_attributes(fd, offset, size,
> + KVM_MEMORY_ATTRIBUTE_PRIVATE);
> +}
> +
> +static inline void gmem_set_shared(int fd, u64 offset, size_t size)
> +{
> + gmem_set_memory_attributes(fd, offset, size, 0);
> +}
> +
> void vm_guest_mem_fallocate(struct kvm_vm *vm, gpa_t gpa, u64 size,
> bool punch_hole);
>
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
* Re: [PATCH v8 29/46] KVM: selftests: Add selftests global for guest memory attributes capability
From: Fuad Tabba @ 2026-06-24 19:26 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-v8-29-9d2959357853@google.com>
On Fri, 19 Jun 2026 at 01:32, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@kernel.org> wrote:
>
> From: Sean Christopherson <seanjc@google.com>
>
> Add a global variable, kvm_has_gmem_attributes, to make the result of
> checking for KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES available to all tests.
>
> kvm_has_gmem_attributes is true if guest_memfd tracks memory attributes, as
> opposed to VM-level tracking.
>
> This global variable is synced to the guest for testing convenience, to
> avoid introducing subtle bugs when host/guest state is desynced.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Cheers,
/fuad
> ---
> tools/testing/selftests/kvm/include/test_util.h | 2 ++
> tools/testing/selftests/kvm/lib/kvm_util.c | 5 +++++
> 2 files changed, 7 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h
> index a56271c237ae9..51287fac8138a 100644
> --- a/tools/testing/selftests/kvm/include/test_util.h
> +++ b/tools/testing/selftests/kvm/include/test_util.h
> @@ -115,6 +115,8 @@ struct guest_random_state {
> extern u32 guest_random_seed;
> extern struct guest_random_state guest_rng;
>
> +extern bool kvm_has_gmem_attributes;
> +
> struct guest_random_state new_guest_random_state(u32 seed);
> u32 guest_random_u32(struct guest_random_state *state);
>
> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> index d5bbc80b2bf1c..b73817f7bc803 100644
> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> @@ -24,6 +24,8 @@ u32 guest_random_seed;
> struct guest_random_state guest_rng;
> static u32 last_guest_seed;
>
> +bool kvm_has_gmem_attributes;
> +
> static size_t vcpu_mmap_sz(void);
>
> int __open_path_or_exit(const char *path, int flags, const char *enoent_help)
> @@ -521,6 +523,7 @@ struct kvm_vm *__vm_create(struct vm_shape shape, u32 nr_runnable_vcpus,
> }
> guest_rng = new_guest_random_state(guest_random_seed);
> sync_global_to_guest(vm, guest_rng);
> + sync_global_to_guest(vm, kvm_has_gmem_attributes);
>
> kvm_arch_vm_post_create(vm, nr_runnable_vcpus);
>
> @@ -2286,6 +2289,8 @@ void __attribute((constructor)) kvm_selftest_init(void)
> guest_random_seed = last_guest_seed = random();
> pr_info("Random seed: 0x%x\n", guest_random_seed);
>
> + kvm_has_gmem_attributes = kvm_has_cap(KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES);
> +
> kvm_selftest_arch_init();
> }
>
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>
^ permalink raw reply
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