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AJvYcCVP7ug4ECKE602iJcsatsl1fOkKQb58ZGtQvN3yRZvWMjKoNssDrsccC8lNHNNkdVpyfZ9t/qs/NR270WU=@vger.kernel.org X-Gm-Message-State: AOJu0Yz/tkcTvFgsuhrLCNvvlUb4upiyl14xTfKZe/RR4uR9ky3U+C2p rZjuEY1EHm0//SFu3BwylHdAdoxAB0a+xa7odgizxVPvqRUXvd/sfWn9MbvY0M1o4piUXn+G2la qGbBAvwB7nWnn7OWClKa89eJzbqmcZw== X-Received: from wrmz10.prod.google.com ([2002:adf:e54a:0:b0:439:b120:9eeb]) (user=sebastianene job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6000:608:b0:439:ad90:389e with SMTP id ffacd0b85a97d-439da8861bdmr24755811f8f.36.1773146990477; Tue, 10 Mar 2026 05:49:50 -0700 (PDT) Date: Tue, 10 Mar 2026 12:49:26 +0000 In-Reply-To: <20260310124933.830025-1-sebastianene@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260310124933.830025-1-sebastianene@google.com> X-Mailer: git-send-email 2.53.0.473.g4a7958ca14-goog Message-ID: <20260310124933.830025-8-sebastianene@google.com> Subject: [PATCH 07/14] KVM: arm64: Restrict host access to the ITS tables From: Sebastian Ene To: alexandru.elisei@arm.com, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, android-kvm@google.com Cc: catalin.marinas@arm.com, dbrazdil@google.com, joey.gouly@arm.com, kees@kernel.org, mark.rutland@arm.com, maz@kernel.org, oupton@kernel.org, perlarsen@google.com, qperret@google.com, rananta@google.com, sebastianene@google.com, smostafa@google.com, suzuki.poulose@arm.com, tabba@google.com, tglx@kernel.org, vdonnefort@google.com, bgrzesik@google.com, will@kernel.org, yuzenghui@huawei.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Setup shadow structures for ITS indirect tables held in the GITS_BASER registers. Make the last level of the Device Table and vPE Table inacessible to the host. In a direct layout configuration, donate the table to the hypervisor since the software is not expected to program them directly. Signed-off-by: Sebastian Ene --- arch/arm64/kvm/hyp/nvhe/its_emulate.c | 143 ++++++++++++++++++++++++++ 1 file changed, 143 insertions(+) diff --git a/arch/arm64/kvm/hyp/nvhe/its_emulate.c b/arch/arm64/kvm/hyp/nvh= e/its_emulate.c index 4a3ccc90a1a9..865a5d6353ed 100644 --- a/arch/arm64/kvm/hyp/nvhe/its_emulate.c +++ b/arch/arm64/kvm/hyp/nvhe/its_emulate.c @@ -141,6 +141,145 @@ static struct pkvm_protected_reg *get_region(phys_add= r_t dev_addr) return NULL; } =20 +static int pkvm_host_unmap_last_level(void *shadow, size_t num_pages, u32 = psz) +{ + u64 *table =3D shadow; + int ret, i, end =3D (num_pages << PAGE_SHIFT) / sizeof(table); + phys_addr_t table_addr; + + for (i =3D 0; i < end; i++) { + if (!(table[i] & GITS_BASER_VALID)) + continue; + + table_addr =3D table[i] & PHYS_MASK; + ret =3D __pkvm_host_donate_hyp(hyp_phys_to_pfn(table_addr), psz >> PAGE_= SHIFT); + if (ret) + goto err_donate; + } + + return 0; +err_donate: + for (i =3D i - 1; i >=3D 0; i--) { + if (!(table[i] & GITS_BASER_VALID)) + continue; + + table_addr =3D table[i] & PHYS_MASK; + __pkvm_hyp_donate_host(hyp_phys_to_pfn(table_addr), psz >> PAGE_SHIFT); + } + return ret; +} + +static int pkvm_share_shadow_table(void *shadow, u64 nr_pages) +{ + u64 i, ret, start_pfn =3D hyp_virt_to_pfn(shadow); + + for (i =3D 0; i < nr_pages; i++) { + ret =3D __pkvm_host_share_hyp(start_pfn + i); + if (ret) + goto unshare; + } + + ret =3D hyp_pin_shared_mem(shadow, shadow + (nr_pages << PAGE_SHIFT)); + if (ret) + goto unshare; + + return ret; +unshare: + for (i =3D i - 1; i >=3D 0; i--) + __pkvm_host_unshare_hyp(start_pfn + i); + return ret; +} + +static void pkvm_unshare_shadow_table(void *shadow, u64 nr_pages) +{ + u64 i, start_pfn =3D hyp_virt_to_pfn(shadow); + + hyp_unpin_shared_mem(shadow, shadow + (nr_pages << PAGE_SHIFT)); + + for (i =3D 0; i < nr_pages; i++) + WARN_ON(__pkvm_host_unshare_hyp(start_pfn + i)); +} + +static void pkvm_host_map_last_level(void *shadow, size_t num_pages, u32 p= sz) +{ + u64 *table; + int i, end =3D (num_pages << PAGE_SHIFT) / sizeof(table); + phys_addr_t table_addr; + + for (i =3D 0; i < end; i++) { + if (!(table[i] & GITS_BASER_VALID)) + continue; + + table_addr =3D table[i] & ~GITS_BASER_VALID; + WARN_ON(__pkvm_hyp_donate_host(hyp_phys_to_pfn(table_addr), psz >> PAGE_= SHIFT)); + } +} + +static int pkvm_setup_its_shadow_baser(struct its_shadow_tables *shadow) +{ + int i, ret; + u64 baser_val, num_pages, type; + void *base, *host_base; + + for (i =3D 0; i < GITS_BASER_NR_REGS; i++) { + baser_val =3D shadow->tables[i].val; + if (!(baser_val & GITS_BASER_VALID)) + continue; + + base =3D kern_hyp_va(shadow->tables[i].base); + num_pages =3D (1 << shadow->tables[i].order); + + ret =3D __pkvm_host_donate_hyp(hyp_virt_to_pfn(base), num_pages); + if (ret) + goto err_donate; + + if (baser_val & GITS_BASER_INDIRECT) { + host_base =3D kern_hyp_va(shadow->tables[i].shadow); + ret =3D pkvm_share_shadow_table(host_base, num_pages); + if (ret) + goto err_with_donation; + + type =3D GITS_BASER_TYPE(baser_val); + if (type =3D=3D GITS_BASER_TYPE_COLLECTION) + continue; + + ret =3D pkvm_host_unmap_last_level(base, num_pages, + shadow->tables[i].psz); + if (ret) + goto err_with_share; + } + } + + return 0; +err_with_share: + pkvm_unshare_shadow_table(host_base, num_pages); +err_with_donation: + __pkvm_hyp_donate_host(hyp_virt_to_pfn(base), num_pages); +err_donate: + for (i =3D i - 1; i >=3D 0; i--) { + baser_val =3D shadow->tables[i].val; + if (!(baser_val & GITS_BASER_VALID)) + continue; + + base =3D kern_hyp_va(shadow->tables[i].base); + num_pages =3D (1 << shadow->tables[i].order); + + WARN_ON(__pkvm_hyp_donate_host(hyp_virt_to_pfn(base), num_pages)); + if (baser_val & GITS_BASER_INDIRECT) { + host_base =3D kern_hyp_va(shadow->tables[i].shadow); + pkvm_unshare_shadow_table(host_base, num_pages); + + type =3D GITS_BASER_TYPE(baser_val); + if (type =3D=3D GITS_BASER_TYPE_COLLECTION) + continue; + + pkvm_host_map_last_level(base, num_pages, shadow->tables[i].psz); + } + } + + return ret; +} + static int pkvm_setup_its_shadow_cmdq(struct its_shadow_tables *shadow) { int ret, i, num_pages; @@ -205,6 +344,10 @@ int pkvm_init_gic_its_emulation(phys_addr_t dev_addr, = void *host_priv_state, if (ret) goto err_with_shadow; =20 + ret =3D pkvm_setup_its_shadow_baser(shadow); + if (ret) + goto err_with_shadow; + its_reg->priv =3D priv_state; =20 hyp_spin_lock_init(&priv_state->its_lock); --=20 2.53.0.473.g4a7958ca14-goog