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AJvYcCVFPtVXDRSDI/SECYh9f0ofEZunE2N/I4BiBMwDkkwKfm7Uu6AUg1fEkQC/9OsYQxKE/9LfgL/r4tk8rU230GGYUL++OKyy X-Gm-Message-State: AOJu0Yxl6JsmzQTDQmZ62Awlu8rpuKHgqFC9gwiT3n7opQtSF8rGf8rM xZ36BlEfNyyvxXn8EihE+jFOJ5wYYQYJktDE2Am8GyKAKv/VD0ppr9tAzR56vrmkKXByT3WNIw= = X-Google-Smtp-Source: AGHT+IEmrrpx8IE5wp+nINUhI83syufxA+Jp+kPhgAEVJtrrWmcQztCabNzm9qoyjLeXrGy74KFBRdDXgQ== X-Received: from fuad.c.googlers.com ([fda3:e722:ac3:cc00:28:9cb1:c0a8:1613]) (user=tabba job=sendgmr) by 2002:a81:f008:0:b0:607:f6f0:bdca with SMTP id p8-20020a81f008000000b00607f6f0bdcamr4659775ywm.7.1708618272146; Thu, 22 Feb 2024 08:11:12 -0800 (PST) Date: Thu, 22 Feb 2024 16:10:30 +0000 In-Reply-To: <20240222161047.402609-1-tabba@google.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240222161047.402609-1-tabba@google.com> X-Mailer: git-send-email 2.44.0.rc1.240.g4c46232300-goog Message-ID: <20240222161047.402609-10-tabba@google.com> Subject: [RFC PATCH v1 09/26] KVM: arm64: Strictly check page type in MEM_RELINQUISH hypercall From: Fuad Tabba To: kvm@vger.kernel.org, kvmarm@lists.linux.dev Cc: pbonzini@redhat.com, chenhuacai@kernel.org, mpe@ellerman.id.au, anup@brainfault.org, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, seanjc@google.com, viro@zeniv.linux.org.uk, brauner@kernel.org, willy@infradead.org, akpm@linux-foundation.org, xiaoyao.li@intel.com, yilun.xu@intel.com, chao.p.peng@linux.intel.com, jarkko@kernel.org, amoorthy@google.com, dmatlack@google.com, yu.c.zhang@linux.intel.com, isaku.yamahata@intel.com, mic@digikod.net, vbabka@suse.cz, vannapurve@google.com, ackerleytng@google.com, mail@maciej.szmigiero.name, david@redhat.com, michael.roth@amd.com, wei.w.wang@intel.com, liam.merwick@oracle.com, isaku.yamahata@gmail.com, kirill.shutemov@linux.intel.com, suzuki.poulose@arm.com, steven.price@arm.com, quic_eberman@quicinc.com, quic_mnalajal@quicinc.com, quic_tsoni@quicinc.com, quic_svaddagi@quicinc.com, quic_cvanscha@quicinc.com, quic_pderrin@quicinc.com, quic_pheragu@quicinc.com, catalin.marinas@arm.com, james.morse@arm.com, yuzenghui@huawei.com, oliver.upton@linux.dev, maz@kernel.org, will@kernel.org, qperret@google.com, keirf@google.com, tabba@google.com Content-Type: text/plain; charset="UTF-8" From: Keir Fraser The VM should only relinquish "normal" pages. For a protected VM, this means PAGE_OWNED; For a normal VM, this means PAGE_SHARED_BORROWED. All other page types are rejected and failure is reported to the caller. Signed-off-by: Keir Fraser Signed-off-by: Fuad Tabba --- arch/arm64/kvm/hyp/nvhe/mem_protect.c | 45 ++++++++++++++++++++++++--- 1 file changed, 41 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index 1dd8eee1ab28..405d6e3e17e0 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -321,13 +321,44 @@ void reclaim_guest_pages(struct pkvm_hyp_vm *vm, struct kvm_hyp_memcache *mc) } } +struct relinquish_data { + enum pkvm_page_state expected_state; + u64 pa; +}; + +static int relinquish_walker(const struct kvm_pgtable_visit_ctx *ctx, + enum kvm_pgtable_walk_flags visit) +{ + kvm_pte_t pte = *ctx->ptep; + struct hyp_page *page; + struct relinquish_data *data = ctx->arg; + enum pkvm_page_state state; + + if (!kvm_pte_valid(pte)) + return 0; + + state = pkvm_getstate(kvm_pgtable_stage2_pte_prot(pte)); + if (state != data->expected_state) + return -EPERM; + + page = hyp_phys_to_page(kvm_pte_to_phys(pte)); + if (state == PKVM_PAGE_OWNED) + page->flags |= HOST_PAGE_NEED_POISONING; + page->flags |= HOST_PAGE_PENDING_RECLAIM; + + data->pa = kvm_pte_to_phys(pte); + + return 0; +} + int __pkvm_guest_relinquish_to_host(struct pkvm_hyp_vcpu *vcpu, u64 ipa, u64 *ppa) { + struct relinquish_data data; struct kvm_pgtable_walker walker = { - .cb = reclaim_walker, - .arg = ppa, - .flags = KVM_PGTABLE_WALK_LEAF + .cb = relinquish_walker, + .flags = KVM_PGTABLE_WALK_LEAF, + .arg = &data, }; struct pkvm_hyp_vm *vm = pkvm_hyp_vcpu_to_hyp_vm(vcpu); int ret; @@ -335,8 +366,13 @@ int __pkvm_guest_relinquish_to_host(struct pkvm_hyp_vcpu *vcpu, host_lock_component(); guest_lock_component(vm); + /* Expected page state depends on VM type. */ + data.expected_state = pkvm_hyp_vcpu_is_protected(vcpu) ? + PKVM_PAGE_OWNED : + PKVM_PAGE_SHARED_BORROWED; + /* Set default pa value to "not found". */ - *ppa = 0; + data.pa = 0; /* If ipa is mapped: sets page flags, and gets the pa. */ ret = kvm_pgtable_walk(&vm->pgt, ipa, PAGE_SIZE, &walker); @@ -348,6 +384,7 @@ int __pkvm_guest_relinquish_to_host(struct pkvm_hyp_vcpu *vcpu, guest_unlock_component(vm); host_unlock_component(); + *ppa = data.pa; return ret; } -- 2.44.0.rc1.240.g4c46232300-goog