linux-kernel - Re: [RESEND PATCH v5 07/11] KVM: arm64: Define kvm_tlb_flush_vmid

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Message-ID: <60ba5bb4-6fad-0e51-2cd5-845610e6631d@redhat.com>
Date:   Thu, 6 Jul 2023 10:04:38 +1000
From:   Gavin Shan <gshan@...hat.com>
To:     Raghavendra Rao Ananta <rananta@...gle.com>
Cc:     Oliver Upton <oliver.upton@...ux.dev>,
        Marc Zyngier <maz@...nel.org>,
        James Morse <james.morse@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Huacai Chen <chenhuacai@...nel.org>,
        Zenghui Yu <yuzenghui@...wei.com>,
        Anup Patel <anup@...infault.org>,
        Atish Patra <atishp@...shpatra.org>,
        Jing Zhang <jingzhangos@...gle.com>,
        Colton Lewis <coltonlewis@...gle.com>,
        David Matlack <dmatlack@...gle.com>,
        linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev,
        linux-mips@...r.kernel.org, kvm-riscv@...ts.infradead.org,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Subject: Re: [RESEND PATCH v5 07/11] KVM: arm64: Define
 kvm_tlb_flush_vmid_range()

On 7/6/23 04:28, Raghavendra Rao Ananta wrote:
> On Tue, Jul 4, 2023 at 5:31 PM Gavin Shan <gshan@...hat.com> wrote:
>> On 6/22/23 03:49, Raghavendra Rao Ananta wrote:
>>> Implement the helper kvm_tlb_flush_vmid_range() that acts
>>> as a wrapper for range-based TLB invalidations. For the
>>> given VMID, use the range-based TLBI instructions to do
>>> the job or fallback to invalidating all the TLB entries.
>>>
>>> Signed-off-by: Raghavendra Rao Ananta <rananta@...gle.com>
>>> ---
>>>    arch/arm64/include/asm/kvm_pgtable.h | 10 ++++++++++
>>>    arch/arm64/kvm/hyp/pgtable.c         | 20 ++++++++++++++++++++
>>>    2 files changed, 30 insertions(+)
>>>
>>
>> It may be reasonable to fold this to PATCH[08/11] since kvm_tlb_flush_vmid_range() is
>> only called by ARM64's kvm_arch_flush_remote_tlbs_range(), which is added by PATCH[08/11].
>> In either way, the changes look good to me:
>>
> Ah, the patches 10 and 11 also call kvm_tlb_flush_vmid_range(), so
> probably it's better to keep the definition isolated?
> 

Thanks for your explanation. It's fine to have two separate patches in this
case. I still need to spend some time to look at PATCH[11/11] whose subject
includes typo (intructions -> instructions)

Thanks,
Gavin

>> Reviewed-by: Gavin Shan <gshan@...hat.com>
>>
>>> diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
>>> index 4cd6762bda805..1b12295a83595 100644
>>> --- a/arch/arm64/include/asm/kvm_pgtable.h
>>> +++ b/arch/arm64/include/asm/kvm_pgtable.h
>>> @@ -682,4 +682,14 @@ enum kvm_pgtable_prot kvm_pgtable_stage2_pte_prot(kvm_pte_t pte);
>>>     *     kvm_pgtable_prot format.
>>>     */
>>>    enum kvm_pgtable_prot kvm_pgtable_hyp_pte_prot(kvm_pte_t pte);
>>> +
>>> +/**
>>> + * kvm_tlb_flush_vmid_range() - Invalidate/flush a range of TLB entries
>>> + *
>>> + * @mmu:     Stage-2 KVM MMU struct
>>> + * @addr:    The base Intermediate physical address from which to invalidate
>>> + * @size:    Size of the range from the base to invalidate
>>> + */
>>> +void kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
>>> +                             phys_addr_t addr, size_t size);
>>>    #endif      /* __ARM64_KVM_PGTABLE_H__ */
>>> diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
>>> index 3d61bd3e591d2..df8ac14d9d3d4 100644
>>> --- a/arch/arm64/kvm/hyp/pgtable.c
>>> +++ b/arch/arm64/kvm/hyp/pgtable.c
>>> @@ -631,6 +631,26 @@ static bool stage2_has_fwb(struct kvm_pgtable *pgt)
>>>        return !(pgt->flags & KVM_PGTABLE_S2_NOFWB);
>>>    }
>>>
>>> +void kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu,
>>> +                             phys_addr_t addr, size_t size)
>>> +{
>>> +     unsigned long pages, inval_pages;
>>> +
>>> +     if (!system_supports_tlb_range()) {
>>> +             kvm_call_hyp(__kvm_tlb_flush_vmid, mmu);
>>> +             return;
>>> +     }
>>> +
>>> +     pages = size >> PAGE_SHIFT;
>>> +     while (pages > 0) {
>>> +             inval_pages = min(pages, MAX_TLBI_RANGE_PAGES);
>>> +             kvm_call_hyp(__kvm_tlb_flush_vmid_range, mmu, addr, inval_pages);
>>> +
>>> +             addr += inval_pages << PAGE_SHIFT;
>>> +             pages -= inval_pages;
>>> +     }
>>> +}
>>> +
>>>    #define KVM_S2_MEMATTR(pgt, attr) PAGE_S2_MEMATTR(attr, stage2_has_fwb(pgt))
>>>
>>>    static int stage2_set_prot_attr(struct kvm_pgtable *pgt, enum kvm_pgtable_prot prot,