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SUSE:SLE-15-SP2:GA
xen.13549
5de1632a-x86-IOMMU-scratch-page-in-quarantine-d...
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File 5de1632a-x86-IOMMU-scratch-page-in-quarantine-dom.patch of Package xen.13549
# Commit ea38867831da67eed0e9c61672c8941016b63dd9 # Date 2019-11-29 18:27:54 +0000 # Author Paul Durrant <pdurrant@amazon.com> # Committer Andrew Cooper <andrew.cooper3@citrix.com> x86 / iommu: set up a scratch page in the quarantine domain This patch introduces a new iommu_op to facilitate a per-implementation quarantine set up, and then further code for x86 implementations (amd and vtd) to set up a read-only scratch page to serve as the source for DMA reads whilst a device is assigned to dom_io. DMA writes will continue to fault as before. The reason for doing this is that some hardware may continue to re-try DMA (despite FLR) in the event of an error, or even BME being cleared, and will fail to deal with DMA read faults gracefully. Having a scratch page mapped will allow pending DMA reads to complete and thus such buggy hardware will eventually be quiesced. NOTE: These modifications are restricted to x86 implementations only as the buggy h/w I am aware of is only used with Xen in an x86 environment. ARM may require similar code but, since I am not aware of the need, this patch does not modify any ARM implementation. Signed-off-by: Paul Durrant <pdurrant@amazon.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> --- a/xen/drivers/passthrough/amd/iommu_map.c +++ b/xen/drivers/passthrough/amd/iommu_map.c @@ -758,6 +758,68 @@ void amd_iommu_share_p2m(struct domain * } } +int __init amd_iommu_quarantine_init(struct domain *d) +{ + struct domain_iommu *hd = dom_iommu(d); + unsigned long max_gfn = + PFN_DOWN((1ul << DEFAULT_DOMAIN_ADDRESS_WIDTH) - 1); + unsigned int level = amd_iommu_get_paging_mode(max_gfn); + uint64_t *table; + + if ( hd->arch.root_table ) + { + ASSERT_UNREACHABLE(); + return 0; + } + + spin_lock(&hd->arch.mapping_lock); + + hd->arch.root_table = alloc_amd_iommu_pgtable(); + if ( !hd->arch.root_table ) + goto out; + + table = __map_domain_page(hd->arch.root_table); + while ( level ) + { + struct page_info *pg; + unsigned int i; + + /* + * The pgtable allocator is fine for the leaf page, as well as + * page table pages, and the resulting allocations are always + * zeroed. + */ + pg = alloc_amd_iommu_pgtable(); + if ( !pg ) + break; + + for ( i = 0; i < PTE_PER_TABLE_SIZE; i++ ) + { + uint32_t *pde = (uint32_t *)&table[i]; + + /* + * PDEs are essentially a subset of PTEs, so this function + * is fine to use even at the leaf. + */ + set_iommu_pde_present(pde, mfn_x(page_to_mfn(pg)), level - 1, + false, true); + } + + unmap_domain_page(table); + table = __map_domain_page(pg); + level--; + } + unmap_domain_page(table); + + out: + spin_unlock(&hd->arch.mapping_lock); + + amd_iommu_flush_all_pages(d); + + /* Pages leaked in failure case */ + return level ? -ENOMEM : 0; +} + /* * Local variables: * mode: C --- a/xen/drivers/passthrough/amd/pci_amd_iommu.c +++ b/xen/drivers/passthrough/amd/pci_amd_iommu.c @@ -120,10 +120,6 @@ static void amd_iommu_setup_domain_devic u8 bus = pdev->bus; const struct domain_iommu *hd = dom_iommu(domain); - /* dom_io is used as a sentinel for quarantined devices */ - if ( domain == dom_io ) - return; - BUG_ON( !hd->arch.root_table || !hd->arch.paging_mode || !iommu->dev_table.buffer ); @@ -226,7 +222,7 @@ static int __must_check allocate_domain_ return rc; } -static int get_paging_mode(unsigned long entries) +int amd_iommu_get_paging_mode(unsigned long entries) { int level = 1; @@ -248,7 +244,8 @@ static int amd_iommu_domain_init(struct /* For pv and dom0, stick with get_paging_mode(max_page) * For HVM dom0, use 2 level page table at first */ - hd->arch.paging_mode = is_hvm_domain(d) ? 2 : get_paging_mode(max_page); + hd->arch.paging_mode = is_hvm_domain(d) ? + 2 : amd_iommu_get_paging_mode(max_page); return 0; } @@ -281,10 +278,6 @@ void amd_iommu_disable_domain_device(str int req_id; u8 bus = pdev->bus; - /* dom_io is used as a sentinel for quarantined devices */ - if ( domain == dom_io ) - return; - BUG_ON ( iommu->dev_table.buffer == NULL ); req_id = get_dma_requestor_id(iommu->seg, PCI_BDF2(bus, devfn)); dte = iommu->dev_table.buffer + (req_id * IOMMU_DEV_TABLE_ENTRY_SIZE); @@ -581,6 +574,7 @@ static void amd_dump_p2m_table(struct do static const struct iommu_ops __initconstrel amd_iommu_ops = { .init = amd_iommu_domain_init, .hwdom_init = amd_iommu_hwdom_init, + .quarantine_init = amd_iommu_quarantine_init, .add_device = amd_iommu_add_device, .remove_device = amd_iommu_remove_device, .assign_device = amd_iommu_assign_device, --- a/xen/drivers/passthrough/iommu.c +++ b/xen/drivers/passthrough/iommu.c @@ -497,6 +497,21 @@ int iommu_iotlb_flush_all(struct domain return rc; } +static int __init iommu_quarantine_init(void) +{ + const struct domain_iommu *hd = dom_iommu(dom_io); + int rc; + + rc = iommu_domain_init(dom_io); + if ( rc ) + return rc; + + if ( !hd->platform_ops->quarantine_init ) + return 0; + + return hd->platform_ops->quarantine_init(dom_io); +} + int __init iommu_setup(void) { int rc = -ENODEV; @@ -530,7 +545,7 @@ int __init iommu_setup(void) printk("I/O virtualisation %sabled\n", iommu_enabled ? "en" : "dis"); if ( iommu_enabled ) { - if ( iommu_domain_init(dom_io) ) + if ( iommu_quarantine_init() ) panic("Could not set up quarantine\n"); printk(" - Dom0 mode: %s\n", --- a/xen/drivers/passthrough/vtd/iommu.c +++ b/xen/drivers/passthrough/vtd/iommu.c @@ -192,7 +192,7 @@ u64 alloc_pgtable_maddr(struct acpi_drhd nodeid_t node = NUMA_NO_NODE; unsigned int i; - rhsa = drhd_to_rhsa(drhd); + rhsa = drhd ? drhd_to_rhsa(drhd) : NULL; if ( rhsa ) node = pxm_to_node(rhsa->proximity_domain); @@ -1340,10 +1340,6 @@ int domain_context_mapping_one( int agaw, rc, ret; bool_t flush_dev_iotlb; - /* dom_io is used as a sentinel for quarantined devices */ - if ( domain == dom_io ) - return 0; - ASSERT(pcidevs_locked()); spin_lock(&iommu->lock); maddr = bus_to_context_maddr(iommu, bus); @@ -1579,10 +1575,6 @@ int domain_context_unmap_one( int iommu_domid, rc, ret; bool_t flush_dev_iotlb; - /* dom_io is used as a sentinel for quarantined devices */ - if ( domain == dom_io ) - return 0; - ASSERT(pcidevs_locked()); spin_lock(&iommu->lock); @@ -1715,10 +1707,6 @@ static int domain_context_unmap(struct d goto out; } - /* dom_io is used as a sentinel for quarantined devices */ - if ( domain == dom_io ) - goto out; - /* * if no other devices under the same iommu owned by this domain, * clear iommu in iommu_bitmap and clear domain_id in domid_bitmp @@ -2736,9 +2724,69 @@ static void vtd_dump_p2m_table(struct do vtd_dump_p2m_table_level(hd->arch.pgd_maddr, agaw_to_level(hd->arch.agaw), 0, 0); } +static int __init intel_iommu_quarantine_init(struct domain *d) +{ + struct domain_iommu *hd = dom_iommu(d); + struct dma_pte *parent; + unsigned int agaw = width_to_agaw(DEFAULT_DOMAIN_ADDRESS_WIDTH); + unsigned int level = agaw_to_level(agaw); + int rc; + + if ( hd->arch.pgd_maddr ) + { + ASSERT_UNREACHABLE(); + return 0; + } + + spin_lock(&hd->arch.mapping_lock); + + hd->arch.pgd_maddr = alloc_pgtable_maddr(NULL, 1); + if ( !hd->arch.pgd_maddr ) + goto out; + + parent = map_vtd_domain_page(hd->arch.pgd_maddr); + while ( level ) + { + uint64_t maddr; + unsigned int offset; + + /* + * The pgtable allocator is fine for the leaf page, as well as + * page table pages, and the resulting allocations are always + * zeroed. + */ + maddr = alloc_pgtable_maddr(NULL, 1); + if ( !maddr ) + break; + + for ( offset = 0; offset < PTE_NUM; offset++ ) + { + struct dma_pte *pte = &parent[offset]; + + dma_set_pte_addr(*pte, maddr); + dma_set_pte_readable(*pte); + } + iommu_flush_cache_page(parent, 1); + + unmap_vtd_domain_page(parent); + parent = map_vtd_domain_page(maddr); + level--; + } + unmap_vtd_domain_page(parent); + + out: + spin_unlock(&hd->arch.mapping_lock); + + rc = iommu_flush_iotlb_all(d); + + /* Pages leaked in failure case */ + return level ? -ENOMEM : rc; +} + const struct iommu_ops __initconstrel intel_iommu_ops = { .init = intel_iommu_domain_init, .hwdom_init = intel_iommu_hwdom_init, + .quarantine_init = intel_iommu_quarantine_init, .add_device = intel_iommu_add_device, .enable_device = intel_iommu_enable_device, .remove_device = intel_iommu_remove_device, --- a/xen/include/asm-x86/hvm/svm/amd-iommu-proto.h +++ b/xen/include/asm-x86/hvm/svm/amd-iommu-proto.h @@ -51,6 +51,9 @@ void get_iommu_features(struct amd_iommu int amd_iommu_init(void); int amd_iommu_update_ivrs_mapping_acpi(void); +int amd_iommu_get_paging_mode(unsigned long entries); +int amd_iommu_quarantine_init(struct domain *d); + /* mapping functions */ int __must_check amd_iommu_map_page(struct domain *d, dfn_t dfn, mfn_t mfn, unsigned int flags, --- a/xen/include/xen/iommu.h +++ b/xen/include/xen/iommu.h @@ -189,6 +189,7 @@ typedef int iommu_grdm_t(xen_pfn_t start struct iommu_ops { int (*init)(struct domain *d); void (*hwdom_init)(struct domain *d); + int (*quarantine_init)(struct domain *d); int (*add_device)(u8 devfn, device_t *dev); int (*enable_device)(device_t *dev); int (*remove_device)(u8 devfn, device_t *dev);
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