* mainline build failure due to fc02735b14ff ("KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS")
@ 2022-07-13 11:28 Sudip Mukherjee (Codethink)
2022-07-13 11:35 ` Peter Zijlstra
0 siblings, 1 reply; 4+ messages in thread
From: Sudip Mukherjee (Codethink) @ 2022-07-13 11:28 UTC (permalink / raw)
To: Josh Poimboeuf, Peter Zijlstra, Borislav Petkov
Cc: Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, x86,
H. Peter Anvin, Paolo Bonzini, Sean Christopherson,
Vitaly Kuznetsov, Wanpeng Li, Jim Mattson, Joerg Roedel,
linux-kernel, kvm, Linus Torvalds
Hi All,
The latest mainline kernel branch fails to build for x86_64 allmodconfig
with clang and the error is:
arch/x86/kernel/cpu/bugs.c:58:21: error: section attribute is specified on redeclared variable [-Werror,-Wsection]
DEFINE_PER_CPU(u64, x86_spec_ctrl_current);
^
./arch/x86/include/asm/nospec-branch.h:283:12: note: previous declaration is here
extern u64 x86_spec_ctrl_current;
git bisect pointed to fc02735b14ff ("KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS")
I will be happy to test any patch or provide any extra log if needed.
--
Regards
Sudip
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: mainline build failure due to fc02735b14ff ("KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS") 2022-07-13 11:28 mainline build failure due to fc02735b14ff ("KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS") Sudip Mukherjee (Codethink) @ 2022-07-13 11:35 ` Peter Zijlstra 2022-07-13 12:22 ` Peter Zijlstra 0 siblings, 1 reply; 4+ messages in thread From: Peter Zijlstra @ 2022-07-13 11:35 UTC (permalink / raw) To: Sudip Mukherjee (Codethink) Cc: Josh Poimboeuf, Borislav Petkov, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin, Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li, Jim Mattson, Joerg Roedel, linux-kernel, kvm, Linus Torvalds On Wed, Jul 13, 2022 at 12:28:38PM +0100, Sudip Mukherjee (Codethink) wrote: > Hi All, > > The latest mainline kernel branch fails to build for x86_64 allmodconfig > with clang and the error is: > > arch/x86/kernel/cpu/bugs.c:58:21: error: section attribute is specified on redeclared variable [-Werror,-Wsection] > DEFINE_PER_CPU(u64, x86_spec_ctrl_current); > ^ > ./arch/x86/include/asm/nospec-branch.h:283:12: note: previous declaration is here > extern u64 x86_spec_ctrl_current; > > > git bisect pointed to fc02735b14ff ("KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS") > > I will be happy to test any patch or provide any extra log if needed. I suspect something like this will do. diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index bb05ed4f46bd..6398d39e66b0 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -280,7 +280,7 @@ static inline void indirect_branch_prediction_barrier(void) /* The Intel SPEC CTRL MSR base value cache */ extern u64 x86_spec_ctrl_base; -extern u64 x86_spec_ctrl_current; +DECLARE_PER_CPU(u64, x86_spec_ctrl_current); extern void write_spec_ctrl_current(u64 val, bool force); extern u64 spec_ctrl_current(void); ^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: mainline build failure due to fc02735b14ff ("KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS") 2022-07-13 11:35 ` Peter Zijlstra @ 2022-07-13 12:22 ` Peter Zijlstra 2022-07-13 13:34 ` Sudip Mukherjee 0 siblings, 1 reply; 4+ messages in thread From: Peter Zijlstra @ 2022-07-13 12:22 UTC (permalink / raw) To: Sudip Mukherjee (Codethink) Cc: Josh Poimboeuf, Borislav Petkov, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin, Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li, Jim Mattson, Joerg Roedel, linux-kernel, kvm, Linus Torvalds On Wed, Jul 13, 2022 at 01:35:22PM +0200, Peter Zijlstra wrote: > On Wed, Jul 13, 2022 at 12:28:38PM +0100, Sudip Mukherjee (Codethink) wrote: > > Hi All, > > > > The latest mainline kernel branch fails to build for x86_64 allmodconfig > > with clang and the error is: > > > > arch/x86/kernel/cpu/bugs.c:58:21: error: section attribute is specified on redeclared variable [-Werror,-Wsection] > > DEFINE_PER_CPU(u64, x86_spec_ctrl_current); > > ^ > > ./arch/x86/include/asm/nospec-branch.h:283:12: note: previous declaration is here > > extern u64 x86_spec_ctrl_current; > > > > > > git bisect pointed to fc02735b14ff ("KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS") > > > > I will be happy to test any patch or provide any extra log if needed. > > I suspect something like this will do. > > diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h > index bb05ed4f46bd..6398d39e66b0 100644 > --- a/arch/x86/include/asm/nospec-branch.h > +++ b/arch/x86/include/asm/nospec-branch.h > @@ -280,7 +280,7 @@ static inline void indirect_branch_prediction_barrier(void) > > /* The Intel SPEC CTRL MSR base value cache */ > extern u64 x86_spec_ctrl_base; > -extern u64 x86_spec_ctrl_current; > +DECLARE_PER_CPU(u64, x86_spec_ctrl_current); > extern void write_spec_ctrl_current(u64 val, bool force); > extern u64 spec_ctrl_current(void); > I hate headers... --- diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index bb05ed4f46bd..cbc3b8348939 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -280,7 +280,6 @@ static inline void indirect_branch_prediction_barrier(void) /* The Intel SPEC CTRL MSR base value cache */ extern u64 x86_spec_ctrl_base; -extern u64 x86_spec_ctrl_current; extern void write_spec_ctrl_current(u64 val, bool force); extern u64 spec_ctrl_current(void); diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index be7c19374fdd..b64512978534 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6831,6 +6831,8 @@ void noinstr vmx_update_host_rsp(struct vcpu_vmx *vmx, unsigned long host_rsp) } } +DECLARE_PER_CPU(u64, x86_spec_ctrl_current); + void noinstr vmx_spec_ctrl_restore_host(struct vcpu_vmx *vmx, unsigned int flags) { ^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: mainline build failure due to fc02735b14ff ("KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS") 2022-07-13 12:22 ` Peter Zijlstra @ 2022-07-13 13:34 ` Sudip Mukherjee 0 siblings, 0 replies; 4+ messages in thread From: Sudip Mukherjee @ 2022-07-13 13:34 UTC (permalink / raw) To: Peter Zijlstra Cc: Josh Poimboeuf, Borislav Petkov, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin, Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li, Jim Mattson, Joerg Roedel, linux-kernel, kvm, Linus Torvalds On Wed, Jul 13, 2022 at 1:22 PM Peter Zijlstra <peterz@infradead.org> wrote: > > On Wed, Jul 13, 2022 at 01:35:22PM +0200, Peter Zijlstra wrote: > > On Wed, Jul 13, 2022 at 12:28:38PM +0100, Sudip Mukherjee (Codethink) wrote: > > > Hi All, > > > > > > The latest mainline kernel branch fails to build for x86_64 allmodconfig > > > with clang and the error is: > > > <snip> > > extern u64 spec_ctrl_current(void); > > > > I hate headers... very short commit message :D > > --- > diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h > index bb05ed4f46bd..cbc3b8348939 100644 > --- a/arch/x86/include/asm/nospec-branch.h > +++ b/arch/x86/include/asm/nospec-branch.h > @@ -280,7 +280,6 @@ static inline void indirect_branch_prediction_barrier(void) > > /* The Intel SPEC CTRL MSR base value cache */ > extern u64 x86_spec_ctrl_base; > -extern u64 x86_spec_ctrl_current; > extern void write_spec_ctrl_current(u64 val, bool force); > extern u64 spec_ctrl_current(void); > > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index be7c19374fdd..b64512978534 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -6831,6 +6831,8 @@ void noinstr vmx_update_host_rsp(struct vcpu_vmx *vmx, unsigned long host_rsp) > } > } > > +DECLARE_PER_CPU(u64, x86_spec_ctrl_current); > + > void noinstr vmx_spec_ctrl_restore_host(struct vcpu_vmx *vmx, > unsigned int flags) > { The build failure is fixed with this change. Thanks. -- Regards Sudip ^ permalink raw reply [flat|nested] 4+ messages in thread
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2022-07-13 11:28 mainline build failure due to fc02735b14ff ("KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS") Sudip Mukherjee (Codethink)
2022-07-13 11:35 ` Peter Zijlstra
2022-07-13 12:22 ` Peter Zijlstra
2022-07-13 13:34 ` Sudip Mukherjee
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