| Date | Wed, 9 Aug 2023 09:50:04 -0400 | From | Josh Poimboeuf <> | Subject | Re: [RFC][PATCH 07/17] x86/cpu/kvm: Provide UNTRAIN_RET_VM |
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On Wed, Aug 09, 2023 at 09:12:25AM +0200, Peter Zijlstra wrote: > With the difference being that UNTRAIN_RET_VM uses > X86_FEATURE_IBPB_ON_VMEXIT instead of X86_FEATURE_ENTRY_IBPB. > > This cures VMEXIT doing potentially unret+IBPB or double IBPB. > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> > --- > arch/x86/include/asm/nospec-branch.h | 11 +++++++++++ > arch/x86/kernel/cpu/bugs.c | 17 ++++++++++++++++- > arch/x86/kvm/svm/vmenter.S | 7 ++----- > 3 files changed, 29 insertions(+), 6 deletions(-) > > --- a/arch/x86/include/asm/nospec-branch.h > +++ b/arch/x86/include/asm/nospec-branch.h > @@ -299,6 +299,17 @@ > #endif > .endm > > +.macro UNTRAIN_RET_VM > +#if defined(CONFIG_CPU_UNRET_ENTRY) || defined(CONFIG_CPU_IBPB_ENTRY) || \ > + defined(CONFIG_CALL_DEPTH_TRACKING) || defined(CONFIG_CPU_SRSO)
Maybe can be simplified?
#if defined(CONFIG_RETHUNK) || defined(CONFIG_CPU_IBPB_ENTRY)
-- Josh
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