Messages in this thread | | | Date | Mon, 6 Sep 2021 11:30:01 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH] x86/tsx: clear RTM and HLE when MSR_IA32_TSX_CTRL is not supported |
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On Mon, Sep 06, 2021 at 10:46:05AM +0800, Hao Peng wrote: > If hypervisor does not support MSR_IA32_TSX_CTRL, but guest supports > RTM and HLE features, it will affect TAA mitigation. > > Signed-off-by: Peng Hao <flyingpeng@tencent.com> > --- > arch/x86/kernel/cpu/tsx.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/arch/x86/kernel/cpu/tsx.c b/arch/x86/kernel/cpu/tsx.c > index 9c7a5f049292..5e852c14fef2 100644 > --- a/arch/x86/kernel/cpu/tsx.c > +++ b/arch/x86/kernel/cpu/tsx.c > @@ -122,6 +122,13 @@ void __init tsx_init(void) > > if (!tsx_ctrl_is_supported()) { > tsx_ctrl_state = TSX_CTRL_NOT_SUPPORTED; > + > + /* If hypervisor does not support MSR_IA32_TSX_CTRL emulation, > + * but guest supports RTM and HLE features, it will affect TAA > + * (tsx_async_abort)mitigation. > + */ > + setup_clear_cpu_cap(X86_FEATURE_RTM); > + setup_clear_cpu_cap(X86_FEATURE_HLE); > return; > }
How does that even happen - the hypervisor does not support the MSR but "guest supports" TSX features?!
I guess the guest is detecting it wrong.
What hypervisor, what guest, how do I reproduce?
Please give full details.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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