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AFNElJ/lXZMaeP/s6GjPc0mwV/8kHVZtyGKlmktWtjbC9aVq/5vAE5xvA6JmkhvpNwSOEQX9ZxCmaYz7wzQmihs=@vger.kernel.org X-Gm-Message-State: AOJu0YxLkDM2SP3wqOO+VD0wSDkusih8RHGpxZ/w/a0aN5ES91X1VIFK /hdnlE9DjXNAgql3oIKyNz62U0CdikO2a8ru9qsVrnnwL9isA5sg7jzzWptfqbd7Bx/E+rbberN nkzjkOOzKlMKIJA== X-Received: from plip13.prod.google.com ([2002:a17:903:38cd:b0:2b4:5901:94ba]) (user=skhawaja job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:3348:b0:2b7:ac66:27ff with SMTP id d9443c01a7336-2b97a933f40mr1685975ad.25.1777312610651; Mon, 27 Apr 2026 10:56:50 -0700 (PDT) Date: Mon, 27 Apr 2026 17:56:26 +0000 In-Reply-To: <20260427175633.1978233-1-skhawaja@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260427175633.1978233-1-skhawaja@google.com> X-Mailer: git-send-email 2.54.0.545.g6539524ca2-goog Message-ID: <20260427175633.1978233-10-skhawaja@google.com> Subject: [PATCH v2 09/16] iommu/vt-d: Restore IOMMU state and reclaimed domain ids From: Samiullah Khawaja To: David Woodhouse , Lu Baolu , Joerg Roedel , Will Deacon , Jason Gunthorpe Cc: Samiullah Khawaja , Robin Murphy , Kevin Tian , Alex Williamson , Shuah Khan , iommu@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Saeed Mahameed , Adithya Jayachandran , Parav Pandit , Leon Romanovsky , William Tu , Pratyush Yadav , Pasha Tatashin , David Matlack , Andrew Morton , Chris Li , Pranjal Shrivastava , Vipin Sharma , YiFei Zhu Content-Type: text/plain; charset="UTF-8" During boot fetch the preserved state of IOMMU unit and if found then restore the state. - Reuse the root_table that was preserved in the previous kernel. - Reclaim the domain ids of the preserved domains for each preserved devices so these are not acquired by another domain. Signed-off-by: Samiullah Khawaja --- drivers/iommu/intel/iommu.c | 55 ++++++++++++++++++++++-------- drivers/iommu/intel/iommu.h | 7 ++++ drivers/iommu/intel/liveupdate.c | 57 ++++++++++++++++++++++++++++++++ 3 files changed, 105 insertions(+), 14 deletions(-) diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 68fecd4e57fa..4118a0861f38 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -670,10 +670,17 @@ void dmar_fault_dump_ptes(struct intel_iommu *iommu, u16 source_id, #endif /* iommu handling */ -static int iommu_alloc_root_entry(struct intel_iommu *iommu) +static int iommu_alloc_root_entry(struct intel_iommu *iommu, + struct iommu_hw_ser *iommu_ser) { struct root_entry *root; + if (iommu_ser) { + intel_iommu_liveupdate_restore_root_table(iommu, iommu_ser); + __iommu_flush_cache(iommu, iommu->root_entry, ROOT_SIZE); + return 0; + } + root = iommu_alloc_pages_node_sz(iommu->node, GFP_ATOMIC, SZ_4K); if (!root) { pr_err("Allocating root entry for %s failed\n", @@ -992,15 +999,16 @@ static void disable_dmar_iommu(struct intel_iommu *iommu) iommu_disable_translation(iommu); } -static void free_dmar_iommu(struct intel_iommu *iommu) +static void free_dmar_iommu(struct intel_iommu *iommu, struct iommu_hw_ser *iommu_ser) { if (iommu->copied_tables) { bitmap_free(iommu->copied_tables); iommu->copied_tables = NULL; } - /* free context mapping */ - free_context_table(iommu); + /* free context mapping if there is no serialized state. */ + if (!iommu_ser) + free_context_table(iommu); if (ecap_prs(iommu->ecap)) intel_iommu_finish_prq(iommu); @@ -1611,6 +1619,7 @@ static int copy_translation_tables(struct intel_iommu *iommu) static int __init init_dmars(void) { + struct iommu_hw_ser *iommu_ser = NULL; struct dmar_drhd_unit *drhd; struct intel_iommu *iommu; int ret; @@ -1633,8 +1642,12 @@ static int __init init_dmars(void) intel_pasid_max_id); } + iommu_ser = iommu_get_preserved_data(iommu->reg_phys, IOMMU_INTEL); + intel_iommu_init_qi(iommu); - init_translation_status(iommu); + + if (!iommu_ser) + init_translation_status(iommu); if (translation_pre_enabled(iommu) && !is_kdump_kernel()) { iommu_disable_translation(iommu); @@ -1648,7 +1661,7 @@ static int __init init_dmars(void) * we could share the same root & context tables * among all IOMMU's. Need to Split it later. */ - ret = iommu_alloc_root_entry(iommu); + ret = iommu_alloc_root_entry(iommu, iommu_ser); if (ret) goto free_iommu; @@ -1732,8 +1745,12 @@ static int __init init_dmars(void) free_iommu: for_each_active_iommu(iommu, drhd) { - disable_dmar_iommu(iommu); - free_dmar_iommu(iommu); + iommu_ser = iommu_get_preserved_data(iommu->reg_phys, IOMMU_INTEL); + + if (!iommu_ser) + disable_dmar_iommu(iommu); + + free_dmar_iommu(iommu, iommu_ser); } return ret; @@ -2107,15 +2124,19 @@ int dmar_parse_one_satc(struct acpi_dmar_header *hdr, void *arg) static int intel_iommu_add(struct dmar_drhd_unit *dmaru) { struct intel_iommu *iommu = dmaru->iommu; + struct iommu_hw_ser *iommu_ser = NULL; int ret; + /* Use IOMMU HW unit MMIO base to identify the preserved state. */ + iommu_ser = iommu_get_preserved_data(iommu->reg_phys, IOMMU_INTEL); + /* * Disable translation if already enabled prior to OS handover. */ - if (iommu->gcmd & DMA_GCMD_TE) + if (!iommu_ser && iommu->gcmd & DMA_GCMD_TE) iommu_disable_translation(iommu); - ret = iommu_alloc_root_entry(iommu); + ret = iommu_alloc_root_entry(iommu, iommu_ser); if (ret) goto out; @@ -2150,9 +2171,10 @@ static int intel_iommu_add(struct dmar_drhd_unit *dmaru) return 0; disable_iommu: - disable_dmar_iommu(iommu); + if (!iommu_ser) + disable_dmar_iommu(iommu); out: - free_dmar_iommu(iommu); + free_dmar_iommu(iommu, iommu_ser); return ret; } @@ -2160,6 +2182,7 @@ int dmar_iommu_hotplug(struct dmar_drhd_unit *dmaru, bool insert) { int ret = 0; struct intel_iommu *iommu = dmaru->iommu; + struct iommu_hw_ser *iommu_ser; if (!intel_iommu_enabled) return 0; @@ -2169,8 +2192,12 @@ int dmar_iommu_hotplug(struct dmar_drhd_unit *dmaru, bool insert) if (insert) { ret = intel_iommu_add(dmaru); } else { - disable_dmar_iommu(iommu); - free_dmar_iommu(iommu); + iommu_ser = iommu_get_preserved_data(iommu->reg_phys, IOMMU_INTEL); + + if (!iommu_ser) + disable_dmar_iommu(iommu); + + free_dmar_iommu(iommu, iommu_ser); } return ret; diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h index 5e0bc17e76bf..b0ec0b471a43 100644 --- a/drivers/iommu/intel/iommu.h +++ b/drivers/iommu/intel/iommu.h @@ -1293,6 +1293,8 @@ int intel_iommu_preserve(struct iommu_device *iommu, struct iommu_hw_ser *iommu_ser); void intel_iommu_unpreserve(struct iommu_device *iommu, struct iommu_hw_ser *iommu_ser); +void intel_iommu_liveupdate_restore_root_table(struct intel_iommu *iommu, + struct iommu_hw_ser *iommu_ser); #else static inline int intel_iommu_preserve_device(struct device *dev, struct iommu_device_ser *device_ser) @@ -1310,6 +1312,11 @@ static inline void intel_iommu_unpreserve(struct iommu_device *iommu, struct iommu_hw_ser *iommu_ser) { } + +static inline void intel_iommu_liveupdate_restore_root_table(struct intel_iommu *iommu, + struct iommu_hw_ser *iommu_ser) +{ +} #endif #ifdef CONFIG_INTEL_IOMMU_SVM diff --git a/drivers/iommu/intel/liveupdate.c b/drivers/iommu/intel/liveupdate.c index 75fa68b701bf..50a63812533f 100644 --- a/drivers/iommu/intel/liveupdate.c +++ b/drivers/iommu/intel/liveupdate.c @@ -83,6 +83,63 @@ static int preserve_iommu_context_table(struct intel_iommu *iommu) return ret; } +static void restore_iommu_context(struct intel_iommu *iommu) +{ + struct context_entry *context; + int i; + + for (i = 0; i < ROOT_ENTRY_NR; i++) { + context = iommu_context_addr(iommu, i, 0, 0); + if (context) + BUG_ON(!kho_restore_folio(virt_to_phys(context))); + + if (!sm_supported(iommu)) + continue; + + context = iommu_context_addr(iommu, i, 0x80, 0); + if (context) + BUG_ON(!kho_restore_folio(virt_to_phys(context))); + } +} + +static int _restore_used_domain_ids(struct iommu_device_ser *ser, void *arg) +{ + int id = ser->domain_iommu_ser.attachment_id; + struct iommu_hw_ser *iommu_hw_ser; + struct intel_iommu *iommu = arg; + + iommu_hw_ser = phys_to_virt(ser->domain_iommu_ser.iommu_phys); + if (iommu_hw_ser->type != IOMMU_INTEL) + return 0; + + /* Only allocate domain ID from associated IOMMU HW unit */ + if (iommu_hw_ser->intel.phys_addr != iommu->reg_phys) + return 0; + + /* + * This can fail as multiple preserved devices can share the same domain + * ID. Since this is done during DMAR init so these failures can be + * ignored. + */ + ida_alloc_range(&iommu->domain_ida, id, id, GFP_ATOMIC); + return 0; +} + +void intel_iommu_liveupdate_restore_root_table(struct intel_iommu *iommu, + struct iommu_hw_ser *iommu_ser) +{ + if (!iommu_ser->intel.restored) + BUG_ON(!kho_restore_folio(iommu_ser->intel.root_table)); + + iommu->root_entry = __va(iommu_ser->intel.root_table); + + if (!iommu_ser->intel.restored) + restore_iommu_context(iommu); + + iommu_ser->intel.restored = 1; + iommu_for_each_preserved_device(_restore_used_domain_ids, iommu); +} + int intel_iommu_preserve_device(struct device *dev, struct iommu_device_ser *device_ser) { -- 2.54.0.545.g6539524ca2-goog