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Message-ID: <fb52139b-5854-6370-7de3-bd87b31e3148@redhat.com>
Date:   Tue, 18 Jul 2023 10:49:30 +0800
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Subject: Re: [PATCH v6 03/11] KVM: Allow range-based TLB invalidation from
 common code
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To:     Raghavendra Rao Ananta <rananta@google.com>
Cc:     Oliver Upton <oliver.upton@linux.dev>,
        Marc Zyngier <maz@kernel.org>,
        James Morse <james.morse@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <seanjc@google.com>,
        Huacai Chen <chenhuacai@kernel.org>,
        Zenghui Yu <yuzenghui@huawei.com>,
        Anup Patel <anup@brainfault.org>,
        Atish Patra <atishp@atishpatra.org>,
        Jing Zhang <jingzhangos@google.com>,
        Colton Lewis <coltonlewis@google.com>,
        David Matlack <dmatlack@google.com>,
        linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
        linux-mips@vger.kernel.org, kvm-riscv@lists.infradead.org,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org, Gavin Shan <gshan@redhat.com>
References: <20230715005405.3689586-1-rananta@google.com>
 <20230715005405.3689586-4-rananta@google.com>
 <199d18de-1214-7683-b87a-03cc7e49719a@redhat.com>
 <CAJHc60zhVco3uTq97vDHMk8cgg1psPtwHT6MN1eKP1Yr18d9cw@mail.gmail.com>
From:   Shaoqin Huang <shahuang@redhat.com>
In-Reply-To: <CAJHc60zhVco3uTq97vDHMk8cgg1psPtwHT6MN1eKP1Yr18d9cw@mail.gmail.com>
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On 7/18/23 00:37, Raghavendra Rao Ananta wrote:
> On Mon, Jul 17, 2023 at 4:40 AM Shaoqin Huang <shahuang@redhat.com> wrote:
>>
>>
>>
>> On 7/15/23 08:53, Raghavendra Rao Ananta wrote:
>>> From: David Matlack <dmatlack@google.com>
>>>
>>> Make kvm_flush_remote_tlbs_range() visible in common code and create a
>>> default implementation that just invalidates the whole TLB.
>>>
>>> This paves the way for several future features/cleanups:
>>>
>>>    - Introduction of range-based TLBI on ARM.
>>>    - Eliminating kvm_arch_flush_remote_tlbs_memslot()
>>>    - Moving the KVM/x86 TDP MMU to common code.
>>>
>>> No functional change intended.
>>>
>>> Signed-off-by: David Matlack <dmatlack@google.com>
>>> Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
>>> Reviewed-by: Gavin Shan <gshan@redhat.com>
>>> ---
>>>    arch/x86/include/asm/kvm_host.h |  3 +++
>>>    arch/x86/kvm/mmu/mmu.c          |  9 ++++-----
>>>    arch/x86/kvm/mmu/mmu_internal.h |  3 ---
>>>    include/linux/kvm_host.h        |  9 +++++++++
>>>    virt/kvm/kvm_main.c             | 13 +++++++++++++
>>>    5 files changed, 29 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
>>> index a2d3cfc2eb75..08900afbf2ad 100644
>>> --- a/arch/x86/include/asm/kvm_host.h
>>> +++ b/arch/x86/include/asm/kvm_host.h
>>> @@ -1804,6 +1804,9 @@ static inline int kvm_arch_flush_remote_tlbs(struct kvm *kvm)
>>>                return -ENOTSUPP;
>>>    }
>>>
>>> +#define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS_RANGE
>>> +int kvm_arch_flush_remote_tlbs_range(struct kvm *kvm, gfn_t start_gfn, u64 pages);
>>> +
>>>    #define kvm_arch_pmi_in_guest(vcpu) \
>>>        ((vcpu) && (vcpu)->arch.handling_intr_from_guest)
>>>
>>> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
>>> index ec169f5c7dce..aaa5e336703a 100644
>>> --- a/arch/x86/kvm/mmu/mmu.c
>>> +++ b/arch/x86/kvm/mmu/mmu.c
>>> @@ -278,16 +278,15 @@ static inline bool kvm_available_flush_remote_tlbs_range(void)
>>>        return kvm_x86_ops.flush_remote_tlbs_range;
>>>    }
>>>
>>> -void kvm_flush_remote_tlbs_range(struct kvm *kvm, gfn_t start_gfn,
>>> -                              gfn_t nr_pages)
>>> +int kvm_arch_flush_remote_tlbs_range(struct kvm *kvm, gfn_t start_gfn, u64 pages)
>>>    {
>>>        int ret = -EOPNOTSUPP;
>>>
>>>        if (kvm_x86_ops.flush_remote_tlbs_range)
>>>                ret = static_call(kvm_x86_flush_remote_tlbs_range)(kvm, start_gfn,
>>> -                                                                nr_pages);
>>> -     if (ret)
>>> -             kvm_flush_remote_tlbs(kvm);
>>> +                                                                     pages);
>> This will be good if parameter pages aligned with parameter kvm.
>>
> Agreed, but pulling 'pages' above brings the char count to 83. If
> that's acceptable, I'm happy to do it in v7.
> Hi Raghavendra,

no need to pulling 'pages' above, just delete one tab, and add some 
space before the pages, just like the original `nr_pages` position.

Thanks,
Shaoqin
> Thank you.
> Raghavendra
>> Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
>>> +
>>> +     return ret;
>>>    }
>>>
>>>    static gfn_t kvm_mmu_page_get_gfn(struct kvm_mmu_page *sp, int index);
>>> diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
>>> index d39af5639ce9..86cb83bb3480 100644
>>> --- a/arch/x86/kvm/mmu/mmu_internal.h
>>> +++ b/arch/x86/kvm/mmu/mmu_internal.h
>>> @@ -170,9 +170,6 @@ bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm,
>>>                                    struct kvm_memory_slot *slot, u64 gfn,
>>>                                    int min_level);
>>>
>>> -void kvm_flush_remote_tlbs_range(struct kvm *kvm, gfn_t start_gfn,
>>> -                              gfn_t nr_pages);
>>> -
>>>    /* Flush the given page (huge or not) of guest memory. */
>>>    static inline void kvm_flush_remote_tlbs_gfn(struct kvm *kvm, gfn_t gfn, int level)
>>>    {
>>> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
>>> index e3f968b38ae9..a731967b24ff 100644
>>> --- a/include/linux/kvm_host.h
>>> +++ b/include/linux/kvm_host.h
>>> @@ -1359,6 +1359,7 @@ int kvm_vcpu_yield_to(struct kvm_vcpu *target);
>>>    void kvm_vcpu_on_spin(struct kvm_vcpu *vcpu, bool yield_to_kernel_mode);
>>>
>>>    void kvm_flush_remote_tlbs(struct kvm *kvm);
>>> +void kvm_flush_remote_tlbs_range(struct kvm *kvm, gfn_t gfn, u64 pages);
>>>
>>>    #ifdef KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE
>>>    int kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min);
>>> @@ -1486,6 +1487,14 @@ static inline int kvm_arch_flush_remote_tlbs(struct kvm *kvm)
>>>    }
>>>    #endif
>>>
>>> +#ifndef __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS_RANGE
>>> +static inline int kvm_arch_flush_remote_tlbs_range(struct kvm *kvm,
>>> +                                                gfn_t gfn, u64 pages)
>>> +{
>>> +     return -EOPNOTSUPP;
>>> +}
>>> +#endif
>>> +
>>>    #ifdef __KVM_HAVE_ARCH_NONCOHERENT_DMA
>>>    void kvm_arch_register_noncoherent_dma(struct kvm *kvm);
>>>    void kvm_arch_unregister_noncoherent_dma(struct kvm *kvm);
>>> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
>>> index d6b050786155..804470fccac7 100644
>>> --- a/virt/kvm/kvm_main.c
>>> +++ b/virt/kvm/kvm_main.c
>>> @@ -366,6 +366,19 @@ void kvm_flush_remote_tlbs(struct kvm *kvm)
>>>    }
>>>    EXPORT_SYMBOL_GPL(kvm_flush_remote_tlbs);
>>>
>>> +void kvm_flush_remote_tlbs_range(struct kvm *kvm, gfn_t gfn, u64 pages)
>>> +{
>>> +     if (!kvm_arch_flush_remote_tlbs_range(kvm, gfn, pages))
>>> +             return;
>>> +
>>> +     /*
>>> +      * Fall back to a flushing entire TLBs if the architecture range-based
>>> +      * TLB invalidation is unsupported or can't be performed for whatever
>>> +      * reason.
>>> +      */
>>> +     kvm_flush_remote_tlbs(kvm);
>>> +}
>>> +
>>>    static void kvm_flush_shadow_all(struct kvm *kvm)
>>>    {
>>>        kvm_arch_flush_shadow_all(kvm);
>>
>> --
>> Shaoqin
>>
> 

-- 
Shaoqin