Re: [PATCH 2/4] KVM: MIPS: rework flush_shadow_* callbacks into one that prepares the flush

[Huacai Chen <chenhuacai@kernel.org>]

Hi, Paolo,

TE mode has been removed in the MIPS tree, can we also remove it in
KVM tree before this rework?

Huacai

On Fri, Apr 2, 2021 at 11:58 PM Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> Both trap-and-emulate and VZ have a single implementation that covers
> both .flush_shadow_all and .flush_shadow_memslot, and both of them end
> with a call to kvm_flush_remote_tlbs.
>
> Unify the callbacks into one and extract the call to kvm_flush_remote_tlbs.
> The next patches will pull it further out of the the architecture-specific
> MMU notifier functions kvm_unmap_hva_range and kvm_set_spte_hva.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  arch/mips/include/asm/kvm_host.h |  9 +--------
>  arch/mips/kvm/mips.c             | 12 ++++++------
>  arch/mips/kvm/mmu.c              |  9 ++++++---
>  arch/mips/kvm/trap_emul.c        | 13 ++-----------
>  arch/mips/kvm/vz.c               | 19 ++++---------------
>  5 files changed, 19 insertions(+), 43 deletions(-)
>
> diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
> index feaa77036b67..6c8c0ab53be2 100644
> --- a/arch/mips/include/asm/kvm_host.h
> +++ b/arch/mips/include/asm/kvm_host.h
> @@ -815,14 +815,7 @@ struct kvm_mips_callbacks {
>         int (*vcpu_init)(struct kvm_vcpu *vcpu);
>         void (*vcpu_uninit)(struct kvm_vcpu *vcpu);
>         int (*vcpu_setup)(struct kvm_vcpu *vcpu);
> -       void (*flush_shadow_all)(struct kvm *kvm);
> -       /*
> -        * Must take care of flushing any cached GPA PTEs (e.g. guest entries in
> -        * VZ root TLB, or T&E GVA page tables and corresponding root TLB
> -        * mappings).
> -        */
> -       void (*flush_shadow_memslot)(struct kvm *kvm,
> -                                    const struct kvm_memory_slot *slot);
> +       void (*prepare_flush_shadow)(struct kvm *kvm);
>         gpa_t (*gva_to_gpa)(gva_t gva);
>         void (*queue_timer_int)(struct kvm_vcpu *vcpu);
>         void (*dequeue_timer_int)(struct kvm_vcpu *vcpu);
> diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
> index 7db8234a4407..867b8de0fc07 100644
> --- a/arch/mips/kvm/mips.c
> +++ b/arch/mips/kvm/mips.c
> @@ -206,7 +206,8 @@ void kvm_arch_flush_shadow_all(struct kvm *kvm)
>         kvm_mips_flush_gpa_pt(kvm, 0, ~0);
>
>         /* Let implementation do the rest */
> -       kvm_mips_callbacks->flush_shadow_all(kvm);
> +       kvm_mips_callbacks->prepare_flush_shadow(kvm);
> +       kvm_flush_remote_tlbs(kvm);
>  }
>
>  void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
> @@ -221,8 +222,7 @@ void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
>         /* Flush slot from GPA */
>         kvm_mips_flush_gpa_pt(kvm, slot->base_gfn,
>                               slot->base_gfn + slot->npages - 1);
> -       /* Let implementation do the rest */
> -       kvm_mips_callbacks->flush_shadow_memslot(kvm, slot);
> +       kvm_arch_flush_remote_tlbs_memslot(kvm, slot);
>         spin_unlock(&kvm->mmu_lock);
>  }
>
> @@ -262,9 +262,8 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
>                 /* Write protect GPA page table entries */
>                 needs_flush = kvm_mips_mkclean_gpa_pt(kvm, new->base_gfn,
>                                         new->base_gfn + new->npages - 1);
> -               /* Let implementation do the rest */
>                 if (needs_flush)
> -                       kvm_mips_callbacks->flush_shadow_memslot(kvm, new);
> +                       kvm_arch_flush_remote_tlbs_memslot(kvm, new);
>                 spin_unlock(&kvm->mmu_lock);
>         }
>  }
> @@ -1000,7 +999,8 @@ void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
>                                         const struct kvm_memory_slot *memslot)
>  {
>         /* Let implementation handle TLB/GVA invalidation */
> -       kvm_mips_callbacks->flush_shadow_memslot(kvm, memslot);
> +       kvm_mips_callbacks->prepare_flush_shadow(kvm);
> +       kvm_flush_remote_tlbs(kvm);
>  }
>
>  long kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
> diff --git a/arch/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c
> index 3dabeda82458..7e055e5dfd3c 100644
> --- a/arch/mips/kvm/mmu.c
> +++ b/arch/mips/kvm/mmu.c
> @@ -491,7 +491,8 @@ int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end,
>  {
>         handle_hva_to_gpa(kvm, start, end, &kvm_unmap_hva_handler, NULL);
>
> -       kvm_mips_callbacks->flush_shadow_all(kvm);
> +       kvm_mips_callbacks->prepare_flush_shadow(kvm);
> +       kvm_flush_remote_tlbs(kvm);
>         return 0;
>  }
>
> @@ -532,8 +533,10 @@ int kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
>         int ret;
>
>         ret = handle_hva_to_gpa(kvm, hva, end, &kvm_set_spte_handler, &pte);
> -       if (ret)
> -               kvm_mips_callbacks->flush_shadow_all(kvm);
> +       if (ret) {
> +               kvm_mips_callbacks->prepare_flush_shadow(kvm);
> +               kvm_flush_remote_tlbs(kvm);
> +       }
>         return 0;
>  }
>
> diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c
> index 0788c00d7e94..5f2df497599c 100644
> --- a/arch/mips/kvm/trap_emul.c
> +++ b/arch/mips/kvm/trap_emul.c
> @@ -687,16 +687,8 @@ static int kvm_trap_emul_vcpu_setup(struct kvm_vcpu *vcpu)
>         return 0;
>  }
>
> -static void kvm_trap_emul_flush_shadow_all(struct kvm *kvm)
> +static void kvm_trap_emul_prepare_flush_shadow(struct kvm *kvm)
>  {
> -       /* Flush GVA page tables and invalidate GVA ASIDs on all VCPUs */
> -       kvm_flush_remote_tlbs(kvm);
> -}
> -
> -static void kvm_trap_emul_flush_shadow_memslot(struct kvm *kvm,
> -                                       const struct kvm_memory_slot *slot)
> -{
> -       kvm_trap_emul_flush_shadow_all(kvm);
>  }
>
>  static u64 kvm_trap_emul_get_one_regs[] = {
> @@ -1280,8 +1272,7 @@ static struct kvm_mips_callbacks kvm_trap_emul_callbacks = {
>         .vcpu_init = kvm_trap_emul_vcpu_init,
>         .vcpu_uninit = kvm_trap_emul_vcpu_uninit,
>         .vcpu_setup = kvm_trap_emul_vcpu_setup,
> -       .flush_shadow_all = kvm_trap_emul_flush_shadow_all,
> -       .flush_shadow_memslot = kvm_trap_emul_flush_shadow_memslot,
> +       .prepare_flush_shadow = kvm_trap_emul_prepare_flush_shadow,
>         .gva_to_gpa = kvm_trap_emul_gva_to_gpa_cb,
>         .queue_timer_int = kvm_mips_queue_timer_int_cb,
>         .dequeue_timer_int = kvm_mips_dequeue_timer_int_cb,
> diff --git a/arch/mips/kvm/vz.c b/arch/mips/kvm/vz.c
> index 2ffbe9264a31..2c75571dc4a2 100644
> --- a/arch/mips/kvm/vz.c
> +++ b/arch/mips/kvm/vz.c
> @@ -3211,32 +3211,22 @@ static int kvm_vz_vcpu_setup(struct kvm_vcpu *vcpu)
>         return 0;
>  }
>
> -static void kvm_vz_flush_shadow_all(struct kvm *kvm)
> +static void kvm_vz_prepare_flush_shadow(struct kvm *kvm)
>  {
> -       if (cpu_has_guestid) {
> -               /* Flush GuestID for each VCPU individually */
> -               kvm_flush_remote_tlbs(kvm);
> -       } else {
> +       if (!cpu_has_guestid) {
>                 /*
>                  * For each CPU there is a single GPA ASID used by all VCPUs in
>                  * the VM, so it doesn't make sense for the VCPUs to handle
>                  * invalidation of these ASIDs individually.
>                  *
>                  * Instead mark all CPUs as needing ASID invalidation in
> -                * asid_flush_mask, and just use kvm_flush_remote_tlbs(kvm) to
> +                * asid_flush_mask, and kvm_flush_remote_tlbs(kvm) will
>                  * kick any running VCPUs so they check asid_flush_mask.
>                  */
>                 cpumask_setall(&kvm->arch.asid_flush_mask);
> -               kvm_flush_remote_tlbs(kvm);
>         }
>  }
>
> -static void kvm_vz_flush_shadow_memslot(struct kvm *kvm,
> -                                       const struct kvm_memory_slot *slot)
> -{
> -       kvm_vz_flush_shadow_all(kvm);
> -}
> -
>  static void kvm_vz_vcpu_reenter(struct kvm_vcpu *vcpu)
>  {
>         int cpu = smp_processor_id();
> @@ -3292,8 +3282,7 @@ static struct kvm_mips_callbacks kvm_vz_callbacks = {
>         .vcpu_init = kvm_vz_vcpu_init,
>         .vcpu_uninit = kvm_vz_vcpu_uninit,
>         .vcpu_setup = kvm_vz_vcpu_setup,
> -       .flush_shadow_all = kvm_vz_flush_shadow_all,
> -       .flush_shadow_memslot = kvm_vz_flush_shadow_memslot,
> +       .prepare_flush_shadow = kvm_vz_prepare_flush_shadow,
>         .gva_to_gpa = kvm_vz_gva_to_gpa_cb,
>         .queue_timer_int = kvm_vz_queue_timer_int_cb,
>         .dequeue_timer_int = kvm_vz_dequeue_timer_int_cb,
> --
> 2.30.1
>
>