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([2a01:e0a:59e:9d80:527b:9dff:feef:3874]) by smtp.gmail.com with ESMTPSA id p2sm6723185wmq.23.2021.11.10.09.03.31 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 10 Nov 2021 09:03:33 -0800 (PST) Subject: Re: [PATCH v4 04/15] KVM: x86: Use generic async PF slot management To: Gavin Shan , kvmarm@lists.cs.columbia.edu Cc: kvm@vger.kernel.org, maz@kernel.org, linux-kernel@vger.kernel.org, shan.gavin@gmail.com, Jonathan.Cameron@huawei.com, pbonzini@redhat.com, vkuznets@redhat.com, will@kernel.org References: <20210815005947.83699-1-gshan@redhat.com> <20210815005947.83699-5-gshan@redhat.com> From: Eric Auger Message-ID: Date: Wed, 10 Nov 2021 18:03:30 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20210815005947.83699-5-gshan@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Gavin, On 8/15/21 2:59 AM, Gavin Shan wrote: > This uses the generic slot management mechanism for asynchronous Now we have moved the hash table management in the generic code, Use this latter ... > page fault by enabling CONFIG_KVM_ASYNC_PF_SLOT because the private > implementation is totally duplicate to the generic one. > > The changes introduced by this is pretty mechanical and shouldn't > cause any logical changes. suggest: No functional change intended. > > Signed-off-by: Gavin Shan > --- > arch/x86/include/asm/kvm_host.h | 2 - > arch/x86/kvm/Kconfig | 1 + > arch/x86/kvm/mmu/mmu.c | 2 +- > arch/x86/kvm/x86.c | 86 +++------------------------------ > 4 files changed, 8 insertions(+), 83 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index 974cbfb1eefe..409c1e7137cd 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -810,7 +810,6 @@ struct kvm_vcpu_arch { > > struct { > bool halted; > - gfn_t gfns[ASYNC_PF_PER_VCPU]; > struct gfn_to_hva_cache data; > u64 msr_en_val; /* MSR_KVM_ASYNC_PF_EN */ > u64 msr_int_val; /* MSR_KVM_ASYNC_PF_INT */ > @@ -1878,7 +1877,6 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, > struct kvm_async_pf *work); > void kvm_arch_async_page_present_queued(struct kvm_vcpu *vcpu); > bool kvm_arch_can_dequeue_async_page_present(struct kvm_vcpu *vcpu); > -extern bool kvm_find_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn); > > int kvm_skip_emulated_instruction(struct kvm_vcpu *vcpu); > int kvm_complete_insn_gp(struct kvm_vcpu *vcpu, int err); > diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig > index ac69894eab88..53a6ef30b6ee 100644 > --- a/arch/x86/kvm/Kconfig > +++ b/arch/x86/kvm/Kconfig > @@ -32,6 +32,7 @@ config KVM > select HAVE_KVM_IRQ_ROUTING > select HAVE_KVM_EVENTFD > select KVM_ASYNC_PF > + select KVM_ASYNC_PF_SLOT > select USER_RETURN_NOTIFIER > select KVM_MMIO > select SCHED_INFO > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index c4f4fa23320e..cd8aaa662ac2 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -3799,7 +3799,7 @@ static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn, > > if (!prefault && kvm_can_do_async_pf(vcpu)) { > trace_kvm_try_async_get_page(cr2_or_gpa, gfn); > - if (kvm_find_async_pf_gfn(vcpu, gfn)) { > + if (kvm_async_pf_find_slot(vcpu, gfn)) { > trace_kvm_async_pf_doublefault(cr2_or_gpa, gfn); > kvm_make_request(KVM_REQ_APF_HALT, vcpu); > return true; > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 7f35d9324b99..a5f7d6122178 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -332,13 +332,6 @@ static struct kmem_cache *kvm_alloc_emulator_cache(void) > > static int emulator_fix_hypercall(struct x86_emulate_ctxt *ctxt); > > -static inline void kvm_async_pf_hash_reset(struct kvm_vcpu *vcpu) > -{ > - int i; > - for (i = 0; i < ASYNC_PF_PER_VCPU; i++) > - vcpu->arch.apf.gfns[i] = ~0; > -} > - > static void kvm_on_user_return(struct user_return_notifier *urn) > { > unsigned slot; > @@ -854,7 +847,7 @@ void kvm_post_set_cr0(struct kvm_vcpu *vcpu, unsigned long old_cr0, unsigned lon > { > if ((cr0 ^ old_cr0) & X86_CR0_PG) { > kvm_clear_async_pf_completion_queue(vcpu); > - kvm_async_pf_hash_reset(vcpu); > + kvm_async_pf_reset_slot(vcpu); > } > > if ((cr0 ^ old_cr0) & KVM_MMU_CR0_ROLE_BITS) > @@ -3118,7 +3111,7 @@ static int kvm_pv_enable_async_pf(struct kvm_vcpu *vcpu, u64 data) > > if (!kvm_pv_async_pf_enabled(vcpu)) { > kvm_clear_async_pf_completion_queue(vcpu); > - kvm_async_pf_hash_reset(vcpu); > + kvm_async_pf_reset_slot(vcpu); > return 0; > } > > @@ -10704,7 +10697,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) > > vcpu->arch.pat = MSR_IA32_CR_PAT_DEFAULT; > > - kvm_async_pf_hash_reset(vcpu); > + kvm_async_pf_reset_slot(vcpu); > kvm_pmu_init(vcpu); > > vcpu->arch.pending_external_vector = -1; > @@ -10828,7 +10821,7 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) > kvmclock_reset(vcpu); > > kvm_clear_async_pf_completion_queue(vcpu); > - kvm_async_pf_hash_reset(vcpu); > + kvm_async_pf_reset_slot(vcpu); > vcpu->arch.apf.halted = false; > > if (vcpu->arch.guest_fpu && kvm_mpx_supported()) { > @@ -11737,73 +11730,6 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work) > kvm_mmu_do_page_fault(vcpu, work->cr2_or_gpa, 0, true); > } > > -static inline u32 kvm_async_pf_hash_fn(gfn_t gfn) > -{ > - BUILD_BUG_ON(!is_power_of_2(ASYNC_PF_PER_VCPU)); > - > - return hash_32(gfn & 0xffffffff, order_base_2(ASYNC_PF_PER_VCPU)); > -} > - > -static inline u32 kvm_async_pf_next_probe(u32 key) > -{ > - return (key + 1) & (ASYNC_PF_PER_VCPU - 1); > -} > - > -static void kvm_add_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn) > -{ > - u32 key = kvm_async_pf_hash_fn(gfn); > - > - while (vcpu->arch.apf.gfns[key] != ~0) > - key = kvm_async_pf_next_probe(key); > - > - vcpu->arch.apf.gfns[key] = gfn; > -} > - > -static u32 kvm_async_pf_gfn_slot(struct kvm_vcpu *vcpu, gfn_t gfn) > -{ > - int i; > - u32 key = kvm_async_pf_hash_fn(gfn); > - > - for (i = 0; i < ASYNC_PF_PER_VCPU && > - (vcpu->arch.apf.gfns[key] != gfn && > - vcpu->arch.apf.gfns[key] != ~0); i++) > - key = kvm_async_pf_next_probe(key); > - > - return key; > -} > - > -bool kvm_find_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn) > -{ > - return vcpu->arch.apf.gfns[kvm_async_pf_gfn_slot(vcpu, gfn)] == gfn; > -} > - > -static void kvm_del_async_pf_gfn(struct kvm_vcpu *vcpu, gfn_t gfn) > -{ > - u32 i, j, k; > - > - i = j = kvm_async_pf_gfn_slot(vcpu, gfn); > - > - if (WARN_ON_ONCE(vcpu->arch.apf.gfns[i] != gfn)) > - return; > - > - while (true) { > - vcpu->arch.apf.gfns[i] = ~0; > - do { > - j = kvm_async_pf_next_probe(j); > - if (vcpu->arch.apf.gfns[j] == ~0) > - return; > - k = kvm_async_pf_hash_fn(vcpu->arch.apf.gfns[j]); > - /* > - * k lies cyclically in ]i,j] > - * | i.k.j | > - * |....j i.k.| or |.k..j i...| > - */ > - } while ((i <= j) ? (i < k && k <= j) : (i < k || k <= j)); > - vcpu->arch.apf.gfns[i] = vcpu->arch.apf.gfns[j]; > - i = j; > - } > -} > - > static inline int apf_put_user_notpresent(struct kvm_vcpu *vcpu) > { > u32 reason = KVM_PV_REASON_PAGE_NOT_PRESENT; > @@ -11867,7 +11793,7 @@ bool kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu, > struct x86_exception fault; > > trace_kvm_async_pf_not_present(work->arch.token, work->cr2_or_gpa); > - kvm_add_async_pf_gfn(vcpu, work->arch.gfn); > + kvm_async_pf_add_slot(vcpu, work->arch.gfn); > > if (kvm_can_deliver_async_pf(vcpu) && > !apf_put_user_notpresent(vcpu)) { > @@ -11904,7 +11830,7 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu, > if (work->wakeup_all) > work->arch.token = ~0; /* broadcast wakeup */ > else > - kvm_del_async_pf_gfn(vcpu, work->arch.gfn); > + kvm_async_pf_remove_slot(vcpu, work->arch.gfn); > trace_kvm_async_pf_ready(work->arch.token, work->cr2_or_gpa); > > if ((work->wakeup_all || work->notpresent_injected) && > Looks good to me Eric