On 7/2/20 3:12 PM, Abhishek Bhardwaj wrote: > This change adds a new kernel configuration that sets the l1d cache > flush setting at compile time rather than at run time. > > Signed-off-by: Abhishek Bhardwaj <abhishekbh@xxxxxxxxxx> > > --- > > Changes in v3: > - Change depends on to only x86_64. > - Remove copy paste errors at the end of the KConfig. > > Changes in v2: > - Fix typo in the help of the new KConfig. > > arch/x86/kernel/cpu/bugs.c | 8 ++++++++ > arch/x86/kvm/Kconfig | 13 +++++++++++++ > 2 files changed, 21 insertions(+) > > diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c > index 0b71970d2d3d2..1dcc875cf5547 100644 > --- a/arch/x86/kernel/cpu/bugs.c > +++ b/arch/x86/kernel/cpu/bugs.c > @@ -1406,7 +1406,15 @@ enum l1tf_mitigations l1tf_mitigation __ro_after_init = L1TF_MITIGATION_FLUSH; > #if IS_ENABLED(CONFIG_KVM_INTEL) > EXPORT_SYMBOL_GPL(l1tf_mitigation); > #endif > +#if (CONFIG_KVM_VMENTRY_L1D_FLUSH == 1) > +enum vmx_l1d_flush_state l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_NEVER; > +#elif (CONFIG_KVM_VMENTRY_L1D_FLUSH == 2) > +enum vmx_l1d_flush_state l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_COND; > +#elif (CONFIG_KVM_VMENTRY_L1D_FLUSH == 3) > +enum vmx_l1d_flush_state l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_ALWAYS; > +#else > enum vmx_l1d_flush_state l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_AUTO; > +#endif > EXPORT_SYMBOL_GPL(l1tf_vmx_mitigation); > > /* > diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig > index b277a2db62676..1f85374a0b812 100644 > --- a/arch/x86/kvm/Kconfig > +++ b/arch/x86/kvm/Kconfig > @@ -107,4 +107,17 @@ config KVM_MMU_AUDIT > This option adds a R/W kVM module parameter 'mmu_audit', which allows > auditing of KVM MMU events at runtime. > > +config KVM_VMENTRY_L1D_FLUSH > + int "L1D cache flush settings (1-3)" > + range 1 3 > + default "2" > + depends on KVM && X86_64 > + help > + This setting determines the L1D cache flush behavior before a VMENTER. > + This is similar to setting the option / parameter to > + kvm-intel.vmentry_l1d_flush. > + 1 - Never flush. > + 2 - Conditionally flush. > + 3 - Always flush. No hurry on this (wait for other comments), but help text should be indented by one tab + 2 spaces, per Documentation/process/coding-style.rst: Lines under a ``config`` definition are indented with one tab, while help text is indented an additional two spaces. > + > endif # VIRTUALIZATION > -- ~Randy
