On Thu, Jul 27, 2023 at 5:40 AM Marc Zyngier <maz@xxxxxxxxxx> wrote:
>
> On Sat, 22 Jul 2023 03:22:46 +0100,
> Raghavendra Rao Ananta <rananta@xxxxxxxxxx> wrote:
> >
> > Define __kvm_tlb_flush_vmid_range() (for VHE and nVHE)
> > to flush a range of stage-2 page-tables using IPA in one go.
> > If the system supports FEAT_TLBIRANGE, the following patches
> > would conviniently replace global TLBI such as vmalls12e1is
> > in the map, unmap, and dirty-logging paths with ripas2e1is
> > instead.
> >
> > Signed-off-by: Raghavendra Rao Ananta <rananta@xxxxxxxxxx>
> > Reviewed-by: Gavin Shan <gshan@xxxxxxxxxx>
> > ---
> > arch/arm64/include/asm/kvm_asm.h | 3 +++
> > arch/arm64/kvm/hyp/nvhe/hyp-main.c | 11 +++++++++++
> > arch/arm64/kvm/hyp/nvhe/tlb.c | 30 ++++++++++++++++++++++++++++++
> > arch/arm64/kvm/hyp/vhe/tlb.c | 27 +++++++++++++++++++++++++++
> > 4 files changed, 71 insertions(+)
> >
> > diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
> > index 7d170aaa2db4..2c27cb8cf442 100644
> > --- a/arch/arm64/include/asm/kvm_asm.h
> > +++ b/arch/arm64/include/asm/kvm_asm.h
> > @@ -70,6 +70,7 @@ enum __kvm_host_smccc_func {
> > __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid_ipa,
> > __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid_ipa_nsh,
> > __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid,
> > + __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid_range,
> > __KVM_HOST_SMCCC_FUNC___kvm_flush_cpu_context,
> > __KVM_HOST_SMCCC_FUNC___kvm_timer_set_cntvoff,
> > __KVM_HOST_SMCCC_FUNC___vgic_v3_read_vmcr,
> > @@ -229,6 +230,8 @@ extern void __kvm_tlb_flush_vmid_ipa(struct kvm_s2_mmu *mmu, phys_addr_t ipa,
> > extern void __kvm_tlb_flush_vmid_ipa_nsh(struct kvm_s2_mmu *mmu,
> > phys_addr_t ipa,
> > int level);
> > +extern void __kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
> > + phys_addr_t start, unsigned long pages);
> > extern void __kvm_tlb_flush_vmid(struct kvm_s2_mmu *mmu);
> >
> > extern void __kvm_timer_set_cntvoff(u64 cntvoff);
> > diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
> > index a169c619db60..857d9bc04fd4 100644
> > --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
> > +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
> > @@ -135,6 +135,16 @@ static void handle___kvm_tlb_flush_vmid_ipa_nsh(struct kvm_cpu_context *host_ctx
> > __kvm_tlb_flush_vmid_ipa_nsh(kern_hyp_va(mmu), ipa, level);
> > }
> >
> > +static void
> > +handle___kvm_tlb_flush_vmid_range(struct kvm_cpu_context *host_ctxt)
> > +{
> > + DECLARE_REG(struct kvm_s2_mmu *, mmu, host_ctxt, 1);
> > + DECLARE_REG(phys_addr_t, start, host_ctxt, 2);
> > + DECLARE_REG(unsigned long, pages, host_ctxt, 3);
> > +
> > + __kvm_tlb_flush_vmid_range(kern_hyp_va(mmu), start, pages);
> > +}
> > +
> > static void handle___kvm_tlb_flush_vmid(struct kvm_cpu_context *host_ctxt)
> > {
> > DECLARE_REG(struct kvm_s2_mmu *, mmu, host_ctxt, 1);
> > @@ -327,6 +337,7 @@ static const hcall_t host_hcall[] = {
> > HANDLE_FUNC(__kvm_tlb_flush_vmid_ipa),
> > HANDLE_FUNC(__kvm_tlb_flush_vmid_ipa_nsh),
> > HANDLE_FUNC(__kvm_tlb_flush_vmid),
> > + HANDLE_FUNC(__kvm_tlb_flush_vmid_range),
> > HANDLE_FUNC(__kvm_flush_cpu_context),
> > HANDLE_FUNC(__kvm_timer_set_cntvoff),
> > HANDLE_FUNC(__vgic_v3_read_vmcr),
> > diff --git a/arch/arm64/kvm/hyp/nvhe/tlb.c b/arch/arm64/kvm/hyp/nvhe/tlb.c
> > index b9991bbd8e3f..09347111c2cd 100644
> > --- a/arch/arm64/kvm/hyp/nvhe/tlb.c
> > +++ b/arch/arm64/kvm/hyp/nvhe/tlb.c
> > @@ -182,6 +182,36 @@ void __kvm_tlb_flush_vmid_ipa_nsh(struct kvm_s2_mmu *mmu,
> > __tlb_switch_to_host(&cxt);
> > }
> >
> > +void __kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
> > + phys_addr_t start, unsigned long pages)
> > +{
> > + struct tlb_inv_context cxt;
> > + unsigned long stride;
> > +
> > + /*
> > + * Since the range of addresses may not be mapped at
> > + * the same level, assume the worst case as PAGE_SIZE
> > + */
> > + stride = PAGE_SIZE;
> > + start = round_down(start, stride);
> > +
> > + /* Switch to requested VMID */
> > + __tlb_switch_to_guest(mmu, &cxt, false);
> > +
> > + __flush_tlb_range_op(ipas2e1is, start, pages, stride, 0, 0, false);
>
> I really think we need an abstraction here. All this ASID and user
> nonsense shouldn't appear here. Something such as
> __flush_s2_tlb_range_op(), which would pass the correct parameters
> that this code shouldn't have to worry about.
>
Yes, a simple wrapper would be nice. I'll implement this in v8.
> I'm also a bit concerned by the fact we completely lose the level
> here. This is a massive fast-path for the CPU, and we don't make use
> of it. It'd be worth thinking of how we can make use of it if at all
> possible...
>
Initial implementation of the series included the 'level', but had
some complexities [1], and so we had to get rid of it for things to at
least be correct.
But, we can think about it and include the 'level' as needed.
- Raghavendra
[1]: https://lore.kernel.org/all/ZCTjirkCgBkT65eP@xxxxxxxxx/
> > +
> > + dsb(ish);
> > + __tlbi(vmalle1is);
> > + dsb(ish);
> > + isb();
> > +
> > + /* See the comment in __kvm_tlb_flush_vmid_ipa() */
> > + if (icache_is_vpipt())
> > + icache_inval_all_pou();
> > +
> > + __tlb_switch_to_host(&cxt);
>
> Another thing is that it is high time that some of this call gets
> refactored. All these helpers are basically the same sequence, only
> differing by a couple of lines. Not something we need to do
> immediately, but eventually we'll have to bite the bullet.
>
> M.
>
> --
> Without deviation from the norm, progress is not possible.
