* linux-next: build warnings after merge of the kvm-arm-fixes tree
@ 2026-07-07 12:11 Mark Brown
2026-07-07 12:58 ` linux-next: Build failure in the final build Mark Brown
2026-07-07 13:17 ` linux-next: build warnings after merge of the kvm-arm-fixes tree Marc Zyngier
0 siblings, 2 replies; 4+ messages in thread
From: Mark Brown @ 2026-07-07 12:11 UTC (permalink / raw)
To: Oliver Upton, Marc Zyngier
Cc: Linux Kernel Mailing List, Linux Next Mailing List
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Hi all,
After merging the kvm-arm-fixes tree, today's linux-next build
(arm64 defconfig) started generating warnings:
In file included from /tmp/next/build/include/linux/limits.h:7,
from /tmp/next/build/include/linux/overflow.h:6,
from /tmp/next/build/include/linux/bits.h:32,
from /tmp/next/build/arch/arm64/include/asm/kvm_pgtable.h:10,
from /tmp/next/build/arch/arm64/kvm/hyp/pgtable.c:11:
/tmp/next/build/arch/arm64/kvm/hyp/pgtable.c: In function 'kvm_pgtable_stage2_relax_perms':
/tmp/next/build/include/vdso/limits.h:8:25: warning: overflow in conversion from 'int' to 's8' {aka 'signed char'} changes value from '2147483647' to '-1' [-Woverflow]
8 | #define INT_MAX ((int)(~0U >> 1))
| ^
/tmp/next/build/arch/arm64/include/asm/tlbflush.h:131:33: note: in expansion of macro 'INT_MAX'
131 | #define TLBI_TTL_UNKNOWN INT_MAX
| ^~~~~~~
/tmp/next/build/arch/arm64/kvm/hyp/pgtable.c:1361:20: note: in expansion of macro 'TLBI_TTL_UNKNOWN'
1361 | s8 level = TLBI_TTL_UNKNOWN;
| ^~~~~~~~~~~~~~~~
In file included from /tmp/next/build/include/linux/limits.h:7,
from /tmp/next/build/include/linux/overflow.h:6,
from /tmp/next/build/include/linux/bits.h:32,
from /tmp/next/build/arch/arm64/include/asm/kvm_pgtable.h:10,
from /tmp/next/build/arch/arm64/kvm/hyp/nvhe/../pgtable.c:11:
/tmp/next/build/arch/arm64/kvm/hyp/nvhe/../pgtable.c: In function 'kvm_pgtable_stage2_relax_perms':
/tmp/next/build/include/vdso/limits.h:8:25: warning: overflow in conversion from 'int' to 's8' {aka 'signed char'} changes value from '2147483647' to '-1' [-Woverflow]
8 | #define INT_MAX ((int)(~0U >> 1))
| ^
/tmp/next/build/arch/arm64/include/asm/tlbflush.h:131:33: note: in expansion of macro 'INT_MAX'
131 | #define TLBI_TTL_UNKNOWN INT_MAX
| ^~~~~~~
/tmp/next/build/arch/arm64/kvm/hyp/nvhe/../pgtable.c:1361:20: note: in expansion of macro 'TLBI_TTL_UNKNOWN'
1361 | s8 level = TLBI_TTL_UNKNOWN;
| ^~~~~~~~~~~~~~~~
Caused by commit
100baf0184896 (KVM: arm64: Ensure level is always initialized when relaxing perms)
I imagine this will cause an allyesconfig build failure when I get to
that due to -Werror.
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^ permalink raw reply [flat|nested] 4+ messages in thread
* linux-next: Build failure in the final build
2026-07-07 12:11 linux-next: build warnings after merge of the kvm-arm-fixes tree Mark Brown
@ 2026-07-07 12:58 ` Mark Brown
2026-07-07 13:17 ` linux-next: build warnings after merge of the kvm-arm-fixes tree Marc Zyngier
1 sibling, 0 replies; 4+ messages in thread
From: Mark Brown @ 2026-07-07 12:58 UTC (permalink / raw)
To: Oliver Upton, Marc Zyngier
Cc: Linux Kernel Mailing List, Linux Next Mailing List
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On Tue, Jul 07, 2026 at 01:11:55PM +0100, Mark Brown wrote:
> After merging the kvm-arm-fixes tree, today's linux-next build
> (arm64 defconfig) started generating warnings:
> In file included from /tmp/next/build/include/linux/limits.h:7,
> from /tmp/next/build/include/linux/overflow.h:6,
> from /tmp/next/build/include/linux/bits.h:32,
> from /tmp/next/build/arch/arm64/include/asm/kvm_pgtable.h:10,
> from /tmp/next/build/arch/arm64/kvm/hyp/pgtable.c:11:
> /tmp/next/build/arch/arm64/kvm/hyp/pgtable.c: In function 'kvm_pgtable_stage2_relax_perms':
> /tmp/next/build/include/vdso/limits.h:8:25: warning: overflow in conversion from 'int' to 's8' {aka 'signed char'} changes value from '2147483647' to '-1' [-Woverflow]
> 8 | #define INT_MAX ((int)(~0U >> 1))
> | ^
> /tmp/next/build/arch/arm64/include/asm/tlbflush.h:131:33: note: in expansion of macro 'INT_MAX'
> 131 | #define TLBI_TTL_UNKNOWN INT_MAX
> | ^~~~~~~
> /tmp/next/build/arch/arm64/kvm/hyp/pgtable.c:1361:20: note: in expansion of macro 'TLBI_TTL_UNKNOWN'
> 1361 | s8 level = TLBI_TTL_UNKNOWN;
> | ^~~~~~~~~~~~~~~~
> In file included from /tmp/next/build/include/linux/limits.h:7,
> from /tmp/next/build/include/linux/overflow.h:6,
> from /tmp/next/build/include/linux/bits.h:32,
> from /tmp/next/build/arch/arm64/include/asm/kvm_pgtable.h:10,
> from /tmp/next/build/arch/arm64/kvm/hyp/nvhe/../pgtable.c:11:
> /tmp/next/build/arch/arm64/kvm/hyp/nvhe/../pgtable.c: In function 'kvm_pgtable_stage2_relax_perms':
> /tmp/next/build/include/vdso/limits.h:8:25: warning: overflow in conversion from 'int' to 's8' {aka 'signed char'} changes value from '2147483647' to '-1' [-Woverflow]
> 8 | #define INT_MAX ((int)(~0U >> 1))
> | ^
> /tmp/next/build/arch/arm64/include/asm/tlbflush.h:131:33: note: in expansion of macro 'INT_MAX'
> 131 | #define TLBI_TTL_UNKNOWN INT_MAX
> | ^~~~~~~
> /tmp/next/build/arch/arm64/kvm/hyp/nvhe/../pgtable.c:1361:20: note: in expansion of macro 'TLBI_TTL_UNKNOWN'
> 1361 | s8 level = TLBI_TTL_UNKNOWN;
> | ^~~~~~~~~~~~~~~~
> Caused by commit
> 100baf0184896 (KVM: arm64: Ensure level is always initialized when relaxing perms)
> I imagine this will cause an allyesconfig build failure when I get to
> that due to -Werror.
Confirmed, nothing later in the merge fixed the warning so -Werror
triggered breaking arm64 allyesconfig.
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: linux-next: build warnings after merge of the kvm-arm-fixes tree
2026-07-07 12:11 linux-next: build warnings after merge of the kvm-arm-fixes tree Mark Brown
2026-07-07 12:58 ` linux-next: Build failure in the final build Mark Brown
@ 2026-07-07 13:17 ` Marc Zyngier
2026-07-07 15:44 ` Oliver Upton
1 sibling, 1 reply; 4+ messages in thread
From: Marc Zyngier @ 2026-07-07 13:17 UTC (permalink / raw)
To: Mark Brown
Cc: Oliver Upton, Linux Kernel Mailing List, Linux Next Mailing List
On Tue, 07 Jul 2026 13:11:55 +0100,
Mark Brown <broonie@kernel.org> wrote:
>
> Hi all,
>
> After merging the kvm-arm-fixes tree, today's linux-next build
> (arm64 defconfig) started generating warnings:
>
> In file included from /tmp/next/build/include/linux/limits.h:7,
> from /tmp/next/build/include/linux/overflow.h:6,
> from /tmp/next/build/include/linux/bits.h:32,
> from /tmp/next/build/arch/arm64/include/asm/kvm_pgtable.h:10,
> from /tmp/next/build/arch/arm64/kvm/hyp/pgtable.c:11:
> /tmp/next/build/arch/arm64/kvm/hyp/pgtable.c: In function 'kvm_pgtable_stage2_relax_perms':
> /tmp/next/build/include/vdso/limits.h:8:25: warning: overflow in conversion from 'int' to 's8' {aka 'signed char'} changes value from '2147483647' to '-1' [-Woverflow]
> 8 | #define INT_MAX ((int)(~0U >> 1))
> | ^
> /tmp/next/build/arch/arm64/include/asm/tlbflush.h:131:33: note: in expansion of macro 'INT_MAX'
> 131 | #define TLBI_TTL_UNKNOWN INT_MAX
> | ^~~~~~~
> /tmp/next/build/arch/arm64/kvm/hyp/pgtable.c:1361:20: note: in expansion of macro 'TLBI_TTL_UNKNOWN'
> 1361 | s8 level = TLBI_TTL_UNKNOWN;
> | ^~~~~~~~~~~~~~~~
> In file included from /tmp/next/build/include/linux/limits.h:7,
> from /tmp/next/build/include/linux/overflow.h:6,
> from /tmp/next/build/include/linux/bits.h:32,
> from /tmp/next/build/arch/arm64/include/asm/kvm_pgtable.h:10,
> from /tmp/next/build/arch/arm64/kvm/hyp/nvhe/../pgtable.c:11:
> /tmp/next/build/arch/arm64/kvm/hyp/nvhe/../pgtable.c: In function 'kvm_pgtable_stage2_relax_perms':
> /tmp/next/build/include/vdso/limits.h:8:25: warning: overflow in conversion from 'int' to 's8' {aka 'signed char'} changes value from '2147483647' to '-1' [-Woverflow]
> 8 | #define INT_MAX ((int)(~0U >> 1))
> | ^
> /tmp/next/build/arch/arm64/include/asm/tlbflush.h:131:33: note: in expansion of macro 'INT_MAX'
> 131 | #define TLBI_TTL_UNKNOWN INT_MAX
> | ^~~~~~~
> /tmp/next/build/arch/arm64/kvm/hyp/nvhe/../pgtable.c:1361:20: note: in expansion of macro 'TLBI_TTL_UNKNOWN'
> 1361 | s8 level = TLBI_TTL_UNKNOWN;
> | ^~~~~~~~~~~~~~~~
>
>
> Caused by commit
>
> 100baf0184896 (KVM: arm64: Ensure level is always initialized when relaxing perms)
>
> I imagine this will cause an allyesconfig build failure when I get to
> that due to -Werror.
Crap, I don't know how I missed that one! And the whole thing is
pretty dodgy anyway:
- level starts as s8
- passed to __kvm_tlb_flush_vmid_ipa_nsh() as int
- passed to __tlbi_level() as u32
- compared to the value 3
The problem is that we are conflating the level of a descriptor and
the TTL, which may or may not be related.
I'm minded to queue something like this on top. Oliver?
Thanks for the heads up,
M.
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 8754c99c22f2f..70dceb20dfada 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -1356,7 +1356,7 @@ int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr,
enum kvm_pgtable_prot prot, enum kvm_pgtable_walk_flags flags)
{
kvm_pte_t xn = 0, set = 0, clr = 0;
- s8 level = TLBI_TTL_UNKNOWN;
+ s8 level;
int ret;
if (prot & KVM_PTE_LEAF_ATTR_HI_SW)
@@ -1379,7 +1379,8 @@ int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr,
ret = stage2_update_leaf_attrs(pgt, addr, 1, set, clr, NULL, &level, flags);
if (!ret || ret == -EAGAIN)
- kvm_call_hyp(__kvm_tlb_flush_vmid_ipa_nsh, pgt->mmu, addr, level);
+ kvm_call_hyp(__kvm_tlb_flush_vmid_ipa_nsh, pgt->mmu, addr,
+ (ret == -EAGAIN) ? TLBI_TTL_UNKNOWN : level);
return ret;
}
--
Without deviation from the norm, progress is not possible.
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: linux-next: build warnings after merge of the kvm-arm-fixes tree
2026-07-07 13:17 ` linux-next: build warnings after merge of the kvm-arm-fixes tree Marc Zyngier
@ 2026-07-07 15:44 ` Oliver Upton
0 siblings, 0 replies; 4+ messages in thread
From: Oliver Upton @ 2026-07-07 15:44 UTC (permalink / raw)
To: Marc Zyngier
Cc: Mark Brown, Linux Kernel Mailing List, Linux Next Mailing List
On Tue, Jul 07, 2026 at 02:17:20PM +0100, Marc Zyngier wrote:
> On Tue, 07 Jul 2026 13:11:55 +0100,
> Mark Brown <broonie@kernel.org> wrote:
> >
> > Hi all,
> >
> > After merging the kvm-arm-fixes tree, today's linux-next build
> > (arm64 defconfig) started generating warnings:
> >
> > In file included from /tmp/next/build/include/linux/limits.h:7,
> > from /tmp/next/build/include/linux/overflow.h:6,
> > from /tmp/next/build/include/linux/bits.h:32,
> > from /tmp/next/build/arch/arm64/include/asm/kvm_pgtable.h:10,
> > from /tmp/next/build/arch/arm64/kvm/hyp/pgtable.c:11:
> > /tmp/next/build/arch/arm64/kvm/hyp/pgtable.c: In function 'kvm_pgtable_stage2_relax_perms':
> > /tmp/next/build/include/vdso/limits.h:8:25: warning: overflow in conversion from 'int' to 's8' {aka 'signed char'} changes value from '2147483647' to '-1' [-Woverflow]
> > 8 | #define INT_MAX ((int)(~0U >> 1))
> > | ^
> > /tmp/next/build/arch/arm64/include/asm/tlbflush.h:131:33: note: in expansion of macro 'INT_MAX'
> > 131 | #define TLBI_TTL_UNKNOWN INT_MAX
> > | ^~~~~~~
> > /tmp/next/build/arch/arm64/kvm/hyp/pgtable.c:1361:20: note: in expansion of macro 'TLBI_TTL_UNKNOWN'
> > 1361 | s8 level = TLBI_TTL_UNKNOWN;
> > | ^~~~~~~~~~~~~~~~
> > In file included from /tmp/next/build/include/linux/limits.h:7,
> > from /tmp/next/build/include/linux/overflow.h:6,
> > from /tmp/next/build/include/linux/bits.h:32,
> > from /tmp/next/build/arch/arm64/include/asm/kvm_pgtable.h:10,
> > from /tmp/next/build/arch/arm64/kvm/hyp/nvhe/../pgtable.c:11:
> > /tmp/next/build/arch/arm64/kvm/hyp/nvhe/../pgtable.c: In function 'kvm_pgtable_stage2_relax_perms':
> > /tmp/next/build/include/vdso/limits.h:8:25: warning: overflow in conversion from 'int' to 's8' {aka 'signed char'} changes value from '2147483647' to '-1' [-Woverflow]
> > 8 | #define INT_MAX ((int)(~0U >> 1))
> > | ^
> > /tmp/next/build/arch/arm64/include/asm/tlbflush.h:131:33: note: in expansion of macro 'INT_MAX'
> > 131 | #define TLBI_TTL_UNKNOWN INT_MAX
> > | ^~~~~~~
> > /tmp/next/build/arch/arm64/kvm/hyp/nvhe/../pgtable.c:1361:20: note: in expansion of macro 'TLBI_TTL_UNKNOWN'
> > 1361 | s8 level = TLBI_TTL_UNKNOWN;
> > | ^~~~~~~~~~~~~~~~
> >
> >
> > Caused by commit
> >
> > 100baf0184896 (KVM: arm64: Ensure level is always initialized when relaxing perms)
> >
> > I imagine this will cause an allyesconfig build failure when I get to
> > that due to -Werror.
>
> Crap, I don't know how I missed that one! And the whole thing is
> pretty dodgy anyway:
>
> - level starts as s8
> - passed to __kvm_tlb_flush_vmid_ipa_nsh() as int
> - passed to __tlbi_level() as u32
> - compared to the value 3
>
> The problem is that we are conflating the level of a descriptor and
> the TTL, which may or may not be related.
>
> I'm minded to queue something like this on top. Oliver?
>
> Thanks for the heads up,
>
> M.
>
> diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
> index 8754c99c22f2f..70dceb20dfada 100644
> --- a/arch/arm64/kvm/hyp/pgtable.c
> +++ b/arch/arm64/kvm/hyp/pgtable.c
> @@ -1356,7 +1356,7 @@ int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr,
> enum kvm_pgtable_prot prot, enum kvm_pgtable_walk_flags flags)
> {
> kvm_pte_t xn = 0, set = 0, clr = 0;
> - s8 level = TLBI_TTL_UNKNOWN;
> + s8 level;
> int ret;
>
> if (prot & KVM_PTE_LEAF_ATTR_HI_SW)
> @@ -1379,7 +1379,8 @@ int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr,
>
> ret = stage2_update_leaf_attrs(pgt, addr, 1, set, clr, NULL, &level, flags);
> if (!ret || ret == -EAGAIN)
> - kvm_call_hyp(__kvm_tlb_flush_vmid_ipa_nsh, pgt->mmu, addr, level);
> + kvm_call_hyp(__kvm_tlb_flush_vmid_ipa_nsh, pgt->mmu, addr,
> + (ret == -EAGAIN) ? TLBI_TTL_UNKNOWN : level);
Looks good, sorry for the mess.
Reviewed-by: Oliver Upton <oupton@kernel.org>
Thanks,
Oliver
^ permalink raw reply [flat|nested] 4+ messages in thread
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2026-07-07 12:11 linux-next: build warnings after merge of the kvm-arm-fixes tree Mark Brown
2026-07-07 12:58 ` linux-next: Build failure in the final build Mark Brown
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2026-07-07 15:44 ` Oliver Upton
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