From patchwork Wed Apr 14 11:23:12 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shameerali Kolothum Thodi X-Patchwork-Id: 12202425 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E2230C433ED for ; Wed, 14 Apr 2021 11:32:26 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 602BF61008 for ; Wed, 14 Apr 2021 11:32:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 602BF61008 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-ID:Date: Subject:CC:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=xM2yOx8aeag6qxgCP1paYbzGWEaoroJpuh1kc+soHd8=; b=HtyUFkr4WaY4psCBvWXhhFOsc +GgpHWQviCZuwsWFYtaaZA+TBHIZp/GOovEin/uGZX3ds5FLwdhAHZCZO41xBVvqKZYivIxi13shL mgI45eUBlEzJICSxsHgnofuFP+5toHsyqjkAmkrL2xCsWOtLgqQE//OXc2qZy/AAqT4m0teaRhh2/ J9yR9aEaxgymDNfDK3a/cKOg/1gL94s6wyJvWogjWGitGa8bzw4yHTrfK6VhOPULNKNQr48fExe9g I1rXMXcoIE5KpaAYuvL8/K9VrA/b/x+V8HeTH1RvetPt/owPnRgrOkUDIO5UgC5m3ySp3I+myTok7 T2IVsBCzw==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lWdix-00CQkY-LO; Wed, 14 Apr 2021 11:30:24 +0000 Received: from bombadil.infradead.org ([2607:7c80:54:e::133]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lWdeS-00COwC-Jp for linux-arm-kernel@desiato.infradead.org; Wed, 14 Apr 2021 11:25:47 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Type:MIME-Version:References: In-Reply-To:Message-ID:Date:Subject:CC:To:From:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=3qe/bX6rF1tTP94GlVWc4rHkUQGmIOANrauv/06GmcA=; b=kWkTTSakUQAaeXTxbY/akMRK7A Lck1XIHuso4u5bj9axrmdO/3ADo4wdiCm7yMXwqR9LAfD6oLZEB90httwMaPPJVu6p3OZFgL61g8Z JjjxQ6YeTL8qljxUcqowdLjMutX9A5FTZT+HzK71Hi2NbX7HcEbTwRGGFSfl4tGi0jWxZ4gNN15AO NDNQ5+VTGEXtdS1DibyPuaHokhHMabxqhyPWp9mmguOYFpFXowM5n+b4vxA+3g8P+RDtd4Pf5cGO8 U785TjtGAkYZOuVQK94d9doxK0QxPZSt7QKrf/6jQfgy+boHBFgCnHmDt8a/0ICtO4uAeZ9m6SZlK ESG2gtIg==; Received: from szxga04-in.huawei.com ([45.249.212.190]) by bombadil.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lWdeP-007i8Z-1F for linux-arm-kernel@lists.infradead.org; Wed, 14 Apr 2021 11:25:43 +0000 Received: from DGGEMS414-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4FL0TQ5q4xz18Hbh; Wed, 14 Apr 2021 19:23:22 +0800 (CST) Received: from S00345302A-PC.china.huawei.com (10.47.82.32) by DGGEMS414-HUB.china.huawei.com (10.3.19.214) with Microsoft SMTP Server id 14.3.498.0; Wed, 14 Apr 2021 19:25:28 +0800 From: Shameer Kolothum To: , , CC: , , , , , , , , Subject: [PATCH v4 16/16] kvm/arm: Align the VMID allocation with the arm64 ASID one Date: Wed, 14 Apr 2021 12:23:12 +0100 Message-ID: <20210414112312.13704-17-shameerali.kolothum.thodi@huawei.com> X-Mailer: git-send-email 2.12.0.windows.1 In-Reply-To: <20210414112312.13704-1-shameerali.kolothum.thodi@huawei.com> References: <20210414112312.13704-1-shameerali.kolothum.thodi@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.47.82.32] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210414_042541_450275_114700FE X-CRM114-Status: GOOD ( 36.27 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Julien Grall At the moment, the VMID algorithm will send an SGI to all the CPUs to force an exit and then broadcast a full TLB flush and I-Cache invalidation. This patch re-use the new ASID allocator. The benefits are: - CPUs are not forced to exit at roll-over. Instead the VMID will be marked reserved and the context will be flushed at next exit. This will reduce the IPIs traffic. - Context invalidation is now per-CPU rather than broadcasted. - Catalin has a formal model of the ASID allocator. With the new algo, the code is now adapted: - The function __kvm_flush_vm_context() has been renamed to __kvm_tlb_flush_local_all() and now only flushing the current CPU context. - The call to update_vmid() will be done with preemption disabled as the new algo requires to store information per-CPU. - The TLBs associated to EL1 will be flushed when booting a CPU to deal with stale information. This was previously done on the allocation of the first VMID of a new generation. Signed-off-by: Julien Grall Signed-off-by: Shameer Kolothum --- Test Results: v4: The measurement was made on a HiSilicon D06 platform with maxcpus set to 8 and with the number of VMID limited to 4-bit. The test involves running concurrently 40 guests with 2 vCPUs. Each guest will then execute hackbench 5 times before exiting. The performance difference between the current algo and the new one are (avg. of 10 runs): - 1.9% less entry/exit from guest - 0.7% faster v3: The measurement was made on a Seattle based SoC (8 CPUs), with the number of VMID limited to 4-bit. The test involves running concurrently 40 guests with 2 vCPUs. Each guest will then execute hackbench 5 times before exiting. The performance difference between the current algo and the new one are: - 2.5% less exit from the guest - 22.4% more flush, although they are now local rather than broadcasted - 0.11% faster (just for the record) --- arch/arm64/include/asm/kvm_asm.h | 4 +- arch/arm64/include/asm/kvm_host.h | 5 +- arch/arm64/include/asm/kvm_mmu.h | 3 +- arch/arm64/kvm/arm.c | 124 +++++++++++------------------ arch/arm64/kvm/hyp/nvhe/hyp-main.c | 6 +- arch/arm64/kvm/hyp/nvhe/tlb.c | 10 +-- arch/arm64/kvm/hyp/vhe/tlb.c | 10 +-- arch/arm64/kvm/mmu.c | 1 - 8 files changed, 65 insertions(+), 98 deletions(-) diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index a7ab84f781f7..29697c5ab2c2 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -44,7 +44,7 @@ #define __KVM_HOST_SMCCC_FUNC___kvm_hyp_init 0 #define __KVM_HOST_SMCCC_FUNC___kvm_vcpu_run 1 -#define __KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context 2 +#define __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_local_all 2 #define __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid_ipa 3 #define __KVM_HOST_SMCCC_FUNC___kvm_tlb_flush_vmid 4 #define __KVM_HOST_SMCCC_FUNC___kvm_flush_cpu_context 5 @@ -182,7 +182,7 @@ DECLARE_KVM_NVHE_SYM(__per_cpu_end); DECLARE_KVM_HYP_SYM(__bp_harden_hyp_vecs); #define __bp_harden_hyp_vecs CHOOSE_HYP_SYM(__bp_harden_hyp_vecs) -extern void __kvm_flush_vm_context(void); +extern void __kvm_tlb_flush_local_all(void); extern void __kvm_flush_cpu_context(struct kvm_s2_mmu *mmu); extern void __kvm_tlb_flush_vmid_ipa(struct kvm_s2_mmu *mmu, phys_addr_t ipa, int level); diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 3d10e6527f7d..5309216e4a94 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -70,9 +70,7 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu); void kvm_arm_vcpu_destroy(struct kvm_vcpu *vcpu); struct kvm_vmid { - /* The VMID generation used for the virt. memory system */ - u64 vmid_gen; - u32 vmid; + atomic64_t id; }; struct kvm_s2_mmu { @@ -631,7 +629,6 @@ void kvm_arm_resume_guest(struct kvm *kvm); ret; \ }) -void force_vm_exit(const cpumask_t *mask); void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot); int handle_exit(struct kvm_vcpu *vcpu, int exception_index); diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index c3080966ef83..43e83df87e3a 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -252,7 +252,8 @@ static __always_inline u64 kvm_get_vttbr(struct kvm_s2_mmu *mmu) u64 cnp = system_supports_cnp() ? VTTBR_CNP_BIT : 0; baddr = mmu->pgd_phys; - vmid_field = (u64)vmid->vmid << VTTBR_VMID_SHIFT; + vmid_field = atomic64_read(&vmid->id) << VTTBR_VMID_SHIFT; + vmid_field &= VTTBR_VMID_MASK(kvm_get_vmid_bits()); return kvm_phys_to_vttbr(baddr) | vmid_field | cnp; } diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 7f06ba76698d..c63242db2d42 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -31,6 +31,7 @@ #include #include #include +#include #include #include #include @@ -55,10 +56,10 @@ static DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page); unsigned long kvm_arm_hyp_percpu_base[NR_CPUS]; DECLARE_KVM_NVHE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params); -/* The VMID used in the VTTBR */ -static atomic64_t kvm_vmid_gen = ATOMIC64_INIT(1); -static u32 kvm_next_vmid; -static DEFINE_SPINLOCK(kvm_vmid_lock); +static DEFINE_PER_CPU(atomic64_t, active_vmids); +static DEFINE_PER_CPU(u64, reserved_vmids); + +static struct asid_info vmid_info; static bool vgic_present; @@ -486,85 +487,22 @@ bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu) return vcpu_mode_priv(vcpu); } -/* Just ensure a guest exit from a particular CPU */ -static void exit_vm_noop(void *info) -{ -} - -void force_vm_exit(const cpumask_t *mask) +static void vmid_flush_cpu_ctxt(void) { - preempt_disable(); - smp_call_function_many(mask, exit_vm_noop, NULL, true); - preempt_enable(); + kvm_call_hyp(__kvm_tlb_flush_local_all); } -/** - * need_new_vmid_gen - check that the VMID is still valid - * @vmid: The VMID to check - * - * return true if there is a new generation of VMIDs being used - * - * The hardware supports a limited set of values with the value zero reserved - * for the host, so we check if an assigned value belongs to a previous - * generation, which requires us to assign a new value. If we're the first to - * use a VMID for the new generation, we must flush necessary caches and TLBs - * on all CPUs. - */ -static bool need_new_vmid_gen(struct kvm_vmid *vmid) +static void vmid_set_reserved_bits(struct asid_info *info) { - u64 current_vmid_gen = atomic64_read(&kvm_vmid_gen); - smp_rmb(); /* Orders read of kvm_vmid_gen and kvm->arch.vmid */ - return unlikely(READ_ONCE(vmid->vmid_gen) != current_vmid_gen); + bitmap_clear(info->map, 0, NUM_CTXT_ASIDS(info)); } - /** * update_vmid - Update the vmid with a valid VMID for the current generation * @vmid: The stage-2 VMID information struct */ static void update_vmid(struct kvm_vmid *vmid) { - if (!need_new_vmid_gen(vmid)) - return; - - spin_lock(&kvm_vmid_lock); - - /* - * We need to re-check the vmid_gen here to ensure that if another vcpu - * already allocated a valid vmid for this vm, then this vcpu should - * use the same vmid. - */ - if (!need_new_vmid_gen(vmid)) { - spin_unlock(&kvm_vmid_lock); - return; - } - - /* First user of a new VMID generation? */ - if (unlikely(kvm_next_vmid == 0)) { - atomic64_inc(&kvm_vmid_gen); - kvm_next_vmid = 1; - - /* - * On SMP we know no other CPUs can use this CPU's or each - * other's VMID after force_vm_exit returns since the - * kvm_vmid_lock blocks them from reentry to the guest. - */ - force_vm_exit(cpu_all_mask); - /* - * Now broadcast TLB + ICACHE invalidation over the inner - * shareable domain to make sure all data structures are - * clean. - */ - kvm_call_hyp(__kvm_flush_vm_context); - } - - vmid->vmid = kvm_next_vmid; - kvm_next_vmid++; - kvm_next_vmid &= (1 << kvm_get_vmid_bits()) - 1; - - smp_wmb(); - WRITE_ONCE(vmid->vmid_gen, atomic64_read(&kvm_vmid_gen)); - - spin_unlock(&kvm_vmid_lock); + asid_check_context(&vmid_info, &vmid->id, NULL); } static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu) @@ -728,8 +666,6 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) */ cond_resched(); - update_vmid(&vcpu->arch.hw_mmu->vmid); - check_vcpu_requests(vcpu); /* @@ -739,6 +675,15 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) */ preempt_disable(); + /* + * The ASID/VMID allocator only tracks active VMIDs per + * physical CPU, and therefore the VMID allocated may not be + * preserved on VMID roll-over if the task was preempted, + * making a thread's VMID inactive. So we need to call + * update_vttbr in non-premptible context. + */ + update_vmid(&vcpu->arch.hw_mmu->vmid); + kvm_pmu_flush_hwstate(vcpu); local_irq_disable(); @@ -777,8 +722,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) */ smp_store_mb(vcpu->mode, IN_GUEST_MODE); - if (ret <= 0 || need_new_vmid_gen(&vcpu->arch.hw_mmu->vmid) || - kvm_request_pending(vcpu)) { + if (ret <= 0 || kvm_request_pending(vcpu)) { vcpu->mode = OUTSIDE_GUEST_MODE; isb(); /* Ensure work in x_flush_hwstate is committed */ kvm_pmu_sync_hwstate(vcpu); @@ -1460,6 +1404,8 @@ static void cpu_hyp_reset(void) { if (!is_kernel_in_hyp_mode()) __hyp_reset_vectors(); + + kvm_call_hyp(__kvm_tlb_flush_local_all); } /* @@ -1635,9 +1581,32 @@ static bool init_psci_relay(void) static int init_common_resources(void) { + struct asid_info *info = &vmid_info; + int err; + + /* + * Initialize the ASID allocator telling it to allocate a single + * VMID per VM. + */ + err = asid_allocator_init(info, kvm_get_vmid_bits(), false); + if (err) { + kvm_err("Failed to initialize VMID allocator.\n"); + return err; + } + + info->active = &active_vmids; + info->reserved = &reserved_vmids; + info->flush_cpu_ctxt_cb = vmid_flush_cpu_ctxt; + info->set_reserved_bits = vmid_set_reserved_bits; + return kvm_set_ipa_limit(); } +static void free_common_resources(void) +{ + asid_allocator_free(&vmid_info); +} + static int init_subsystems(void) { int err = 0; @@ -1918,7 +1887,7 @@ int kvm_arch_init(void *opaque) err = kvm_arm_init_sve(); if (err) - return err; + goto out_err; if (!in_hyp_mode) { err = init_hyp_mode(); @@ -1952,6 +1921,7 @@ int kvm_arch_init(void *opaque) if (!in_hyp_mode) teardown_hyp_mode(); out_err: + free_common_resources(); return err; } diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c index 936328207bde..62027448d534 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -25,9 +25,9 @@ static void handle___kvm_vcpu_run(struct kvm_cpu_context *host_ctxt) cpu_reg(host_ctxt, 1) = __kvm_vcpu_run(kern_hyp_va(vcpu)); } -static void handle___kvm_flush_vm_context(struct kvm_cpu_context *host_ctxt) +static void handle___kvm_tlb_flush_local_all(struct kvm_cpu_context *host_ctxt) { - __kvm_flush_vm_context(); + __kvm_tlb_flush_local_all(); } static void handle___kvm_tlb_flush_vmid_ipa(struct kvm_cpu_context *host_ctxt) @@ -112,7 +112,7 @@ typedef void (*hcall_t)(struct kvm_cpu_context *); static const hcall_t host_hcall[] = { HANDLE_FUNC(__kvm_vcpu_run), - HANDLE_FUNC(__kvm_flush_vm_context), + HANDLE_FUNC(__kvm_tlb_flush_local_all), HANDLE_FUNC(__kvm_tlb_flush_vmid_ipa), HANDLE_FUNC(__kvm_tlb_flush_vmid), HANDLE_FUNC(__kvm_flush_cpu_context), diff --git a/arch/arm64/kvm/hyp/nvhe/tlb.c b/arch/arm64/kvm/hyp/nvhe/tlb.c index 229b06748c20..3f1fc5125e9e 100644 --- a/arch/arm64/kvm/hyp/nvhe/tlb.c +++ b/arch/arm64/kvm/hyp/nvhe/tlb.c @@ -138,10 +138,10 @@ void __kvm_flush_cpu_context(struct kvm_s2_mmu *mmu) __tlb_switch_to_host(&cxt); } -void __kvm_flush_vm_context(void) +void __kvm_tlb_flush_local_all(void) { - dsb(ishst); - __tlbi(alle1is); + dsb(nshst); + __tlbi(alle1); /* * VIPT and PIPT caches are not affected by VMID, so no maintenance @@ -153,7 +153,7 @@ void __kvm_flush_vm_context(void) * */ if (icache_is_vpipt()) - asm volatile("ic ialluis"); + asm volatile("ic iallu" : : ); - dsb(ish); + dsb(nsh); } diff --git a/arch/arm64/kvm/hyp/vhe/tlb.c b/arch/arm64/kvm/hyp/vhe/tlb.c index 66f17349f0c3..89f229e77b7d 100644 --- a/arch/arm64/kvm/hyp/vhe/tlb.c +++ b/arch/arm64/kvm/hyp/vhe/tlb.c @@ -142,10 +142,10 @@ void __kvm_flush_cpu_context(struct kvm_s2_mmu *mmu) __tlb_switch_to_host(&cxt); } -void __kvm_flush_vm_context(void) +void __kvm_tlb_flush_local_all(void) { - dsb(ishst); - __tlbi(alle1is); + dsb(nshst); + __tlbi(alle1); /* * VIPT and PIPT caches are not affected by VMID, so no maintenance @@ -157,7 +157,7 @@ void __kvm_flush_vm_context(void) * */ if (icache_is_vpipt()) - asm volatile("ic ialluis"); + asm volatile("ic iallu" : : ); - dsb(ish); + dsb(nsh); } diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 8711894db8c2..4933fc9a13fb 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -390,7 +390,6 @@ int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu) mmu->kvm = kvm; mmu->pgt = pgt; mmu->pgd_phys = __pa(pgt->pgd); - mmu->vmid.vmid_gen = 0; return 0; out_destroy_pgtable: