From patchwork Thu Nov 10 19:02:53 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 13039202 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 52183C43217 for ; Thu, 10 Nov 2022 19:04:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229812AbiKJTEm (ORCPT ); Thu, 10 Nov 2022 14:04:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47488 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231181AbiKJTE0 (ORCPT ); Thu, 10 Nov 2022 14:04:26 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 26D1D4044C for ; Thu, 10 Nov 2022 11:04:25 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id D3169B820D5 for ; Thu, 10 Nov 2022 19:04:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4E23AC43470; Thu, 10 Nov 2022 19:04:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1668107062; bh=jezZlti5LdTsUtuFt2KuI3nDydQiBAyxtHvdym7P+SM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=C/kpSL6QY06A7VejFXA3U73wRJKAbzXqgRWBOmDxJgNWSXmM7dhmdBKpH1kXH0+Ee s300wZRqnVBLs7+94OMyiQWvaUJvmj+4dtL786LjGIwYMhBb9fuEKMcgfx3XZw+IhZ fNvQeY6WVyTiPZSsvHuYfAk/XEgTjDEs+84NZMFvZ7TxMzjArMirVZwZ3Va5vBHUyT fooSOBqKDDpqCRnbqqx+aQWTa6JLRbx8o7cGufD01QEy45kLPQqm7puJGh60AqHqI9 wjP5esXoBvoF389Yg5F+Rq3AMDQaSt0hwURbW2jWt2FJSJRW+HZWOJ0kIYHvLJKU73 RRun6RUPIY4zA== From: Will Deacon To: kvmarm@lists.linux.dev Cc: Will Deacon , Sean Christopherson , Vincent Donnefort , Alexandru Elisei , Catalin Marinas , =?utf-8?q?Philippe_Mathieu-Daud?= =?utf-8?q?=C3=A9?= , James Morse , Chao Peng , Quentin Perret , Suzuki K Poulose , Mark Rutland , Fuad Tabba , Oliver Upton , Marc Zyngier , kernel-team@android.com, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH v6 20/26] KVM: arm64: Return guest memory from EL2 via dedicated teardown memcache Date: Thu, 10 Nov 2022 19:02:53 +0000 Message-Id: <20221110190259.26861-21-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20221110190259.26861-1-will@kernel.org> References: <20221110190259.26861-1-will@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Quentin Perret Rather than relying on the host to free the previously-donated pKVM hypervisor VM pages explicitly on teardown, introduce a dedicated teardown memcache which allows the host to reclaim guest memory resources without having to keep track of all of the allocations made by the pKVM hypervisor at EL2. Tested-by: Vincent Donnefort Co-developed-by: Fuad Tabba Signed-off-by: Fuad Tabba Signed-off-by: Quentin Perret Signed-off-by: Will Deacon --- arch/arm64/include/asm/kvm_host.h | 7 +---- arch/arm64/kvm/hyp/include/nvhe/mem_protect.h | 2 +- arch/arm64/kvm/hyp/nvhe/mem_protect.c | 17 ++++++---- arch/arm64/kvm/hyp/nvhe/pkvm.c | 25 ++++++++++++--- arch/arm64/kvm/pkvm.c | 31 ++++--------------- 5 files changed, 39 insertions(+), 43 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 57218f0c449e..63307e7dc9c5 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -176,12 +176,7 @@ typedef unsigned int pkvm_handle_t; struct kvm_protected_vm { pkvm_handle_t handle; - - struct { - void *pgd; - void *vm; - void *vcpus[KVM_MAX_VCPUS]; - } hyp_donations; + struct kvm_hyp_memcache teardown_mc; }; struct kvm_arch { diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h index 420b87e755a4..b7bdbe63deed 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h @@ -76,7 +76,7 @@ void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt); int hyp_pin_shared_mem(void *from, void *to); void hyp_unpin_shared_mem(void *from, void *to); -void reclaim_guest_pages(struct pkvm_hyp_vm *vm); +void reclaim_guest_pages(struct pkvm_hyp_vm *vm, struct kvm_hyp_memcache *mc); int refill_memcache(struct kvm_hyp_memcache *mc, unsigned long min_pages, struct kvm_hyp_memcache *host_mc); diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index 0162afba6dc4..94cd48f7850e 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -260,19 +260,24 @@ int kvm_guest_prepare_stage2(struct pkvm_hyp_vm *vm, void *pgd) return 0; } -void reclaim_guest_pages(struct pkvm_hyp_vm *vm) +void reclaim_guest_pages(struct pkvm_hyp_vm *vm, struct kvm_hyp_memcache *mc) { - void *pgd = vm->pgt.pgd; - unsigned long nr_pages; - - nr_pages = kvm_pgtable_stage2_pgd_size(vm->kvm.arch.vtcr) >> PAGE_SHIFT; + void *addr; + /* Dump all pgtable pages in the hyp_pool */ guest_lock_component(vm); kvm_pgtable_stage2_destroy(&vm->pgt); vm->kvm.arch.mmu.pgd_phys = 0ULL; guest_unlock_component(vm); - WARN_ON(__pkvm_hyp_donate_host(hyp_virt_to_pfn(pgd), nr_pages)); + /* Drain the hyp_pool into the memcache */ + addr = hyp_alloc_pages(&vm->pool, 0); + while (addr) { + memset(hyp_virt_to_page(addr), 0, sizeof(struct hyp_page)); + push_hyp_memcache(mc, addr, hyp_virt_to_phys); + WARN_ON(__pkvm_hyp_donate_host(hyp_virt_to_pfn(addr), 1)); + addr = hyp_alloc_pages(&vm->pool, 0); + } } int __pkvm_prot_finalize(void) diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c index 212752c48506..81835c2f4c5a 100644 --- a/arch/arm64/kvm/hyp/nvhe/pkvm.c +++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c @@ -527,8 +527,21 @@ int __pkvm_init_vcpu(pkvm_handle_t handle, struct kvm_vcpu *host_vcpu, return ret; } +static void +teardown_donated_memory(struct kvm_hyp_memcache *mc, void *addr, size_t size) +{ + size = PAGE_ALIGN(size); + memset(addr, 0, size); + + for (void *start = addr; start < addr + size; start += PAGE_SIZE) + push_hyp_memcache(mc, start, hyp_virt_to_phys); + + unmap_donated_memory_noclear(addr, size); +} + int __pkvm_teardown_vm(pkvm_handle_t handle) { + struct kvm_hyp_memcache *mc; struct pkvm_hyp_vm *hyp_vm; struct kvm *host_kvm; unsigned int idx; @@ -547,25 +560,27 @@ int __pkvm_teardown_vm(pkvm_handle_t handle) goto err_unlock; } + host_kvm = hyp_vm->host_kvm; + /* Ensure the VMID is clean before it can be reallocated */ __kvm_tlb_flush_vmid(&hyp_vm->kvm.arch.mmu); remove_vm_table_entry(handle); hyp_spin_unlock(&vm_table_lock); /* Reclaim guest pages (including page-table pages) */ - reclaim_guest_pages(hyp_vm); + mc = &host_kvm->arch.pkvm.teardown_mc; + reclaim_guest_pages(hyp_vm, mc); unpin_host_vcpus(hyp_vm->vcpus, hyp_vm->nr_vcpus); - /* Return the metadata pages to the host */ + /* Push the metadata pages to the teardown memcache */ for (idx = 0; idx < hyp_vm->nr_vcpus; ++idx) { struct pkvm_hyp_vcpu *hyp_vcpu = hyp_vm->vcpus[idx]; - unmap_donated_memory(hyp_vcpu, sizeof(*hyp_vcpu)); + teardown_donated_memory(mc, hyp_vcpu, sizeof(*hyp_vcpu)); } - host_kvm = hyp_vm->host_kvm; vm_size = pkvm_get_hyp_vm_size(hyp_vm->kvm.created_vcpus); - unmap_donated_memory(hyp_vm, vm_size); + teardown_donated_memory(mc, hyp_vm, vm_size); hyp_unpin_shared_mem(host_kvm, host_kvm + 1); return 0; diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c index 8c443b915e43..cf56958b1492 100644 --- a/arch/arm64/kvm/pkvm.c +++ b/arch/arm64/kvm/pkvm.c @@ -147,8 +147,6 @@ static int __pkvm_create_hyp_vm(struct kvm *host_kvm) handle = ret; host_kvm->arch.pkvm.handle = handle; - host_kvm->arch.pkvm.hyp_donations.pgd = pgd; - host_kvm->arch.pkvm.hyp_donations.vm = hyp_vm; /* Donate memory for the vcpus at hyp and initialize it. */ hyp_vcpu_sz = PAGE_ALIGN(PKVM_HYP_VCPU_SIZE); @@ -167,12 +165,12 @@ static int __pkvm_create_hyp_vm(struct kvm *host_kvm) goto destroy_vm; } - host_kvm->arch.pkvm.hyp_donations.vcpus[idx] = hyp_vcpu; - ret = kvm_call_hyp_nvhe(__pkvm_init_vcpu, handle, host_vcpu, hyp_vcpu); - if (ret) + if (ret) { + free_pages_exact(hyp_vcpu, hyp_vcpu_sz); goto destroy_vm; + } } return 0; @@ -201,30 +199,13 @@ int pkvm_create_hyp_vm(struct kvm *host_kvm) void pkvm_destroy_hyp_vm(struct kvm *host_kvm) { - unsigned long idx, nr_vcpus = host_kvm->created_vcpus; - size_t pgd_sz, hyp_vm_sz; - - if (host_kvm->arch.pkvm.handle) + if (host_kvm->arch.pkvm.handle) { WARN_ON(kvm_call_hyp_nvhe(__pkvm_teardown_vm, host_kvm->arch.pkvm.handle)); - - host_kvm->arch.pkvm.handle = 0; - - for (idx = 0; idx < nr_vcpus; ++idx) { - void *hyp_vcpu = host_kvm->arch.pkvm.hyp_donations.vcpus[idx]; - - if (!hyp_vcpu) - break; - - free_pages_exact(hyp_vcpu, PAGE_ALIGN(PKVM_HYP_VCPU_SIZE)); } - hyp_vm_sz = PAGE_ALIGN(size_add(PKVM_HYP_VM_SIZE, - size_mul(sizeof(void *), nr_vcpus))); - pgd_sz = kvm_pgtable_stage2_pgd_size(host_kvm->arch.vtcr); - - free_pages_exact(host_kvm->arch.pkvm.hyp_donations.vm, hyp_vm_sz); - free_pages_exact(host_kvm->arch.pkvm.hyp_donations.pgd, pgd_sz); + host_kvm->arch.pkvm.handle = 0; + free_hyp_memcache(&host_kvm->arch.pkvm.teardown_mc); } int pkvm_init_host_vm(struct kvm *host_kvm)