On Wed, Jun 27, 2018 at 02:59:12PM -0700, Junaid Shahid wrote:
> Remove the implicit flush from the set_cr3 handlers, so that the
> callers are able to decide whether to flush the TLB or not.
>
> Signed-off-by: Junaid Shahid <junaids@xxxxxxxxxx>
> ---
> arch/x86/kvm/mmu.c | 2 ++
> arch/x86/kvm/mmu.h | 1 -
> arch/x86/kvm/svm.c | 4 ----
> arch/x86/kvm/vmx.c | 1 -
> 4 files changed, 2 insertions(+), 6 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index 9b73cfcef917..d3a04cf6514b 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -4070,6 +4070,7 @@ static bool fast_cr3_switch(struct kvm_vcpu *vcpu, gpa_t new_cr3,
>
> kvm_make_request(KVM_REQ_LOAD_CR3, vcpu);
> kvm_make_request(KVM_REQ_MMU_SYNC, vcpu);
> + kvm_x86_ops->tlb_flush(vcpu, true);
Paolo, can you weigh in on whether or not its ok to use
kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu) here instead of directly
calling tlb_flush()? Making a request seems more appropriate but
Junaid was concerned that doing so would inflate vcpu->stat.tlb_flush.
> __clear_sp_write_flooding_count(
> page_header(mmu->root_hpa));
>
> @@ -4851,6 +4852,7 @@ int kvm_mmu_load(struct kvm_vcpu *vcpu)
> if (r)
> goto out;
> kvm_mmu_load_cr3(vcpu);
> + kvm_x86_ops->tlb_flush(vcpu, true);
> out:
> return r;
> }
> diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
> index 3177127cee96..6a2a97d8015b 100644
> --- a/arch/x86/kvm/mmu.h
> +++ b/arch/x86/kvm/mmu.h
> @@ -88,7 +88,6 @@ static inline int kvm_mmu_reload(struct kvm_vcpu *vcpu)
>
> static inline void kvm_mmu_load_cr3(struct kvm_vcpu *vcpu)
> {
> - /* set_cr3() should ensure TLB has been flushed */
> if (VALID_PAGE(vcpu->arch.mmu.root_hpa))
> vcpu->arch.mmu.set_cr3(vcpu, vcpu->arch.mmu.root_hpa);
> }
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index f059a73f0fd0..be9931cad409 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -2884,7 +2884,6 @@ static void nested_svm_set_tdp_cr3(struct kvm_vcpu *vcpu,
>
> svm->vmcb->control.nested_cr3 = __sme_set(root);
> mark_dirty(svm->vmcb, VMCB_NPT);
> - svm_flush_tlb(vcpu, true);
> }
>
> static void nested_svm_inject_npf_exit(struct kvm_vcpu *vcpu,
> @@ -5766,7 +5765,6 @@ static void svm_set_cr3(struct kvm_vcpu *vcpu, unsigned long root)
>
> svm->vmcb->save.cr3 = __sme_set(root);
> mark_dirty(svm->vmcb, VMCB_CR);
> - svm_flush_tlb(vcpu, true);
> }
>
> static void set_tdp_cr3(struct kvm_vcpu *vcpu, unsigned long root)
> @@ -5779,8 +5777,6 @@ static void set_tdp_cr3(struct kvm_vcpu *vcpu, unsigned long root)
> /* Also sync guest cr3 here in case we live migrate */
> svm->vmcb->save.cr3 = kvm_read_cr3(vcpu);
> mark_dirty(svm->vmcb, VMCB_CR);
> -
> - svm_flush_tlb(vcpu, true);
> }
>
> static int is_disabled(void)
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 4a582a242873..0afa2fdcbac3 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -4964,7 +4964,6 @@ static void vmx_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
> ept_load_pdptrs(vcpu);
> }
>
> - vmx_flush_tlb(vcpu, true);
> vmcs_writel(GUEST_CR3, guest_cr3);
> }
>
> --
> 2.18.0.rc2.346.g013aa6912e-goog
>
