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AJvYcCWHX7Y5l0dqfIUYx6HDb1gRo7ARqmYXLjGlZ/NclNwZma7VfJhB+1zZoCg1Ve7YVxzf1BX8polcX2YtRW285s4q@lists.infradead.org X-Gm-Message-State: AOJu0YwF+8Bl5Sw6p9uyuRr4PK87M5KgF3jOKAxcS9Q08XqOzCptBwCV 0KiLNvhTEVUmTosAgSxRdI66fbTsDbKAb5JgaUzcZ6fLa3HkALcSODHWwvxZZdYi8T+khrw6MK4 QUsUErQ== X-Google-Smtp-Source: AGHT+IGR8bsfJ02p9vHy+seXY+BmxTKO7YUK2HiE8eFkkm9wUjhjecldaQfmnnOt9C+IS5sr/2xmgAJlbcZ8 X-Received: from big-boi.c.googlers.com ([fda3:e722:ac3:cc00:31:98fb:c0a8:129]) (user=qperret job=sendgmr) by 2002:a25:c710:0:b0:e30:d61e:b110 with SMTP id 3f1490d57ef6-e33025662cdmr10816276.5.1730727154895; Mon, 04 Nov 2024 05:32:34 -0800 (PST) Date: Mon, 4 Nov 2024 13:31:57 +0000 In-Reply-To: <20241104133204.85208-1-qperret@google.com> Mime-Version: 1.0 References: <20241104133204.85208-1-qperret@google.com> X-Mailer: git-send-email 2.47.0.163.g1226f6d8fa-goog Message-ID: <20241104133204.85208-12-qperret@google.com> Subject: [PATCH 11/18] KVM: arm64: Introduce __pkvm_host_unshare_guest() From: Quentin Perret To: Marc Zyngier , Oliver Upton , Joey Gouly , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon Cc: Fuad Tabba , Vincent Donnefort , Sebastian Ene , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241104_053236_440575_C0383B82 X-CRM114-Status: GOOD ( 13.64 ) 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 In preparation for letting the host unmap pages from non-protected guests, introduce a new hypercall implementing the host-unshare-guest transition. Signed-off-by: Quentin Perret --- arch/arm64/include/asm/kvm_asm.h | 1 + arch/arm64/kvm/hyp/include/nvhe/mem_protect.h | 1 + arch/arm64/kvm/hyp/include/nvhe/pkvm.h | 5 ++ arch/arm64/kvm/hyp/nvhe/hyp-main.c | 24 ++++++ arch/arm64/kvm/hyp/nvhe/mem_protect.c | 78 +++++++++++++++++++ 5 files changed, 109 insertions(+) diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index b69390108c5a..e67efee936b6 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -66,6 +66,7 @@ enum __kvm_host_smccc_func { __KVM_HOST_SMCCC_FUNC___pkvm_host_share_hyp, __KVM_HOST_SMCCC_FUNC___pkvm_host_unshare_hyp, __KVM_HOST_SMCCC_FUNC___pkvm_host_share_guest, + __KVM_HOST_SMCCC_FUNC___pkvm_host_unshare_guest, __KVM_HOST_SMCCC_FUNC___kvm_adjust_pc, __KVM_HOST_SMCCC_FUNC___kvm_vcpu_run, __KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context, diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h index a7976e50f556..e528a42ed60e 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h @@ -40,6 +40,7 @@ int __pkvm_hyp_donate_host(u64 pfn, u64 nr_pages); int __pkvm_host_share_ffa(u64 pfn, u64 nr_pages); int __pkvm_host_unshare_ffa(u64 pfn, u64 nr_pages); int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu, enum kvm_pgtable_prot prot); +int __pkvm_host_unshare_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm); bool addr_is_memory(phys_addr_t phys); int host_stage2_idmap_locked(phys_addr_t addr, u64 size, enum kvm_pgtable_prot prot); diff --git a/arch/arm64/kvm/hyp/include/nvhe/pkvm.h b/arch/arm64/kvm/hyp/include/nvhe/pkvm.h index be52c5b15e21..5dfc9ece9aa5 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/pkvm.h +++ b/arch/arm64/kvm/hyp/include/nvhe/pkvm.h @@ -64,6 +64,11 @@ static inline bool pkvm_hyp_vcpu_is_protected(struct pkvm_hyp_vcpu *hyp_vcpu) return vcpu_is_protected(&hyp_vcpu->vcpu); } +static inline bool pkvm_hyp_vm_is_protected(struct pkvm_hyp_vm *hyp_vm) +{ + return kvm_vm_is_protected(&hyp_vm->kvm); +} + void pkvm_hyp_vm_table_init(void *tbl); int __pkvm_init_vm(struct kvm *host_kvm, unsigned long vm_hva, diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c index 32bdf6b27958..68bbef69d99a 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -242,6 +242,29 @@ static void handle___pkvm_host_share_guest(struct kvm_cpu_context *host_ctxt) cpu_reg(host_ctxt, 1) = ret; } +static void handle___pkvm_host_unshare_guest(struct kvm_cpu_context *host_ctxt) +{ + DECLARE_REG(pkvm_handle_t, handle, host_ctxt, 1); + DECLARE_REG(u64, gfn, host_ctxt, 2); + struct pkvm_hyp_vm *hyp_vm; + int ret = -EINVAL; + + if (!is_protected_kvm_enabled()) + goto out; + + hyp_vm = get_pkvm_hyp_vm(handle); + if (!hyp_vm) + goto out; + if (pkvm_hyp_vm_is_protected(hyp_vm)) + goto put_hyp_vm; + + ret = __pkvm_host_unshare_guest(gfn, hyp_vm); +put_hyp_vm: + put_pkvm_hyp_vm(hyp_vm); +out: + cpu_reg(host_ctxt, 1) = ret; +} + static void handle___kvm_adjust_pc(struct kvm_cpu_context *host_ctxt) { DECLARE_REG(struct kvm_vcpu *, vcpu, host_ctxt, 1); @@ -459,6 +482,7 @@ static const hcall_t host_hcall[] = { HANDLE_FUNC(__pkvm_host_share_hyp), HANDLE_FUNC(__pkvm_host_unshare_hyp), HANDLE_FUNC(__pkvm_host_share_guest), + HANDLE_FUNC(__pkvm_host_unshare_guest), HANDLE_FUNC(__kvm_adjust_pc), HANDLE_FUNC(__kvm_vcpu_run), HANDLE_FUNC(__kvm_flush_vm_context), diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index a69d7212b64c..f7476a29e1a9 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -1413,3 +1413,81 @@ int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu, return ret; } + +static int guest_get_valid_pte(struct pkvm_hyp_vm *vm, u64 *phys, u64 ipa, u8 order, kvm_pte_t *pte) +{ + size_t size = PAGE_SIZE << order; + s8 level; + + if (order && size != PMD_SIZE) + return -EINVAL; + + WARN_ON(kvm_pgtable_get_leaf(&vm->pgt, ipa, pte, &level)); + + if (kvm_granule_size(level) != size) + return -E2BIG; + + if (!kvm_pte_valid(*pte)) + return -ENOENT; + + *phys = kvm_pte_to_phys(*pte); + + return 0; +} + +static int __check_host_unshare_guest(struct pkvm_hyp_vm *vm, u64 *phys, u64 ipa) +{ + enum pkvm_page_state state; + struct hyp_page *page; + kvm_pte_t pte; + int ret; + + ret = guest_get_valid_pte(vm, phys, ipa, 0, &pte); + if (ret) + return ret; + + state = guest_get_page_state(pte, ipa); + if (state != PKVM_PAGE_SHARED_BORROWED) + return -EPERM; + + ret = range_is_allowed_memory(*phys, *phys + PAGE_SIZE); + if (ret) + return ret; + + page = hyp_phys_to_page(*phys); + if (page->host_state != PKVM_PAGE_SHARED_OWNED) + return -EPERM; + WARN_ON(!page->host_share_guest_count); + + return 0; +} + +int __pkvm_host_unshare_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm) +{ + u64 ipa = hyp_pfn_to_phys(gfn); + struct hyp_page *page; + u64 phys; + int ret; + + host_lock_component(); + guest_lock_component(hyp_vm); + + ret = __check_host_unshare_guest(hyp_vm, &phys, ipa); + if (ret) + goto unlock; + + ret = kvm_pgtable_stage2_unmap(&hyp_vm->pgt, ipa, PAGE_SIZE); + if (ret) + goto unlock; + + page = hyp_phys_to_page(phys); + page->host_share_guest_count--; + if (!page->host_share_guest_count) + WARN_ON(__host_set_page_state_range(phys, PAGE_SIZE, PKVM_PAGE_OWNED)); + +unlock: + guest_unlock_component(hyp_vm); + host_unlock_component(); + + return ret; +}