* 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 [-- Attachment #1: Type: text/plain, Size: 2710 bytes --] 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. [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 488 bytes --] ^ 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
end of thread, other threads:[~2026-07-07 15:44 UTC | newest] Thread overview: 4+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 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 ` linux-next: build warnings after merge of the kvm-arm-fixes tree Marc Zyngier 2026-07-07 15:44 ` Oliver Upton
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