On Wed, 2025-03-26 at 19:36 +0000, Yosry Ahmed wrote: > KVM_REQ_TLB_FLUSH is used to flush all TLB entries for all contexts > (e.g. in kvm_flush_remote_tlbs()). Flush both L1 and L2 ASIDs in > svm_flush_tlb_all() to handle it appropriately. > > This is currently not required as nested transitions do unconditional > TLB flushes, but this is a step toward eliminating that. > > Signed-off-by: Yosry Ahmed <yosry.ahmed@xxxxxxxxx> > --- > arch/x86/kvm/svm/nested.c | 1 - > arch/x86/kvm/svm/svm.c | 10 ++-------- > 2 files changed, 2 insertions(+), 9 deletions(-) > > diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c > index c336ab63c6da3..56a4ff480bb3d 100644 > --- a/arch/x86/kvm/svm/nested.c > +++ b/arch/x86/kvm/svm/nested.c > @@ -491,7 +491,6 @@ static void nested_svm_entry_tlb_flush(struct kvm_vcpu *vcpu) > * TODO: optimize unconditional TLB flush/MMU sync. A partial list of > * things to fix before this can be conditional: > * > - * - Flush TLBs for both L1 and L2 remote TLB flush > * - Honor L1's request to flush an ASID on nested VMRUN > * - Sync nested NPT MMU on VMRUN that flushes L2's ASID[*] > * - Don't crush a pending TLB flush in vmcb02 on nested VMRUN > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c > index fb6b9f88a1504..4cad1085936bb 100644 > --- a/arch/x86/kvm/svm/svm.c > +++ b/arch/x86/kvm/svm/svm.c > @@ -4064,14 +4064,8 @@ static void svm_flush_tlb_all(struct kvm_vcpu *vcpu) > if (WARN_ON_ONCE(svm_hv_is_enlightened_tlb_enabled(vcpu))) > hv_flush_remote_tlbs(vcpu->kvm); > > - /* > - * Flush only the current ASID even if the TLB flush was invoked via > - * kvm_flush_remote_tlbs(). Although flushing remote TLBs requires all > - * ASIDs to be flushed, KVM uses a single ASID for L1 and L2, and > - * unconditionally does a TLB flush on both nested VM-Enter and nested > - * VM-Exit (via kvm_mmu_reset_context()). > - */ > - svm_flush_tlb_asid(vcpu, is_guest_mode(vcpu)); > + svm_flush_tlb_asid(vcpu, false); > + svm_flush_tlb_asid(vcpu, true); > } > > static void svm_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t gva) Reviewed-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx> Best regards, Maxim Levitsky
