[xen master] AMD/IOMMU: respect AtsDisabled device flag

[patchbot@xxxxxxx]

commit 246a0cd415af377d26576dd9962ee78c0f83f1f9
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Fri Oct 15 12:46:42 2021 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri Oct 15 12:46:42 2021 +0200

    AMD/IOMMU: respect AtsDisabled device flag
    
    IVHD entries may specify that ATS is to be blocked for a device or range
    of devices. Honor firmware telling us so.
    
    While adding respective checks I noticed that the 2nd conditional in
    amd_iommu_setup_domain_device() failed to check the IOMMU's capability.
    Add the missing part of the condition there, as no good can come from
    enabling ATS on a device when the IOMMU is not capable of dealing with
    ATS requests.
    
    For actually using ACPI_IVHD_ATS_DISABLED, make its expansion no longer
    exhibit UB.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Paul Durrant <paul@xxxxxxx>
---
 xen/drivers/passthrough/amd/iommu.h         |  1 +
 xen/drivers/passthrough/amd/iommu_acpi.c    | 20 +++++++++++---------
 xen/drivers/passthrough/amd/pci_amd_iommu.c |  8 +++++---
 xen/include/acpi/actbl2.h                   |  2 +-
 4 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/xen/drivers/passthrough/amd/iommu.h 
b/xen/drivers/passthrough/amd/iommu.h
index a915433f56..49c4bbd7e1 100644
--- a/xen/drivers/passthrough/amd/iommu.h
+++ b/xen/drivers/passthrough/amd/iommu.h
@@ -120,6 +120,7 @@ struct ivrs_mappings {
     uint16_t dte_requestor_id;
     bool valid:1;
     bool dte_allow_exclusion:1;
+    bool block_ats:1;
 
     /* ivhd device data settings */
     uint8_t device_flags;
diff --git a/xen/drivers/passthrough/amd/iommu_acpi.c 
b/xen/drivers/passthrough/amd/iommu_acpi.c
index 71c323fb33..4aed8a17fd 100644
--- a/xen/drivers/passthrough/amd/iommu_acpi.c
+++ b/xen/drivers/passthrough/amd/iommu_acpi.c
@@ -55,8 +55,8 @@ union acpi_ivhd_device {
 };
 
 static void __init add_ivrs_mapping_entry(
-    uint16_t bdf, uint16_t alias_id, uint8_t flags, bool alloc_irt,
-    struct amd_iommu *iommu)
+    uint16_t bdf, uint16_t alias_id, uint8_t flags, unsigned int ext_flags,
+    bool alloc_irt, struct amd_iommu *iommu)
 {
     struct ivrs_mappings *ivrs_mappings = get_ivrs_mappings(iommu->seg);
 
@@ -66,6 +66,7 @@ static void __init add_ivrs_mapping_entry(
     ivrs_mappings[bdf].dte_requestor_id = alias_id;
 
     /* override flags for range of devices */
+    ivrs_mappings[bdf].block_ats = ext_flags & ACPI_IVHD_ATS_DISABLED;
     ivrs_mappings[bdf].device_flags = flags;
 
     /* Don't map an IOMMU by itself. */
@@ -499,7 +500,7 @@ static u16 __init parse_ivhd_device_select(
         return 0;
     }
 
-    add_ivrs_mapping_entry(bdf, bdf, select->header.data_setting, false,
+    add_ivrs_mapping_entry(bdf, bdf, select->header.data_setting, 0, false,
                            iommu);
 
     return sizeof(*select);
@@ -545,7 +546,7 @@ static u16 __init parse_ivhd_device_range(
     AMD_IOMMU_DEBUG(" Dev_Id Range: %#x -> %#x\n", first_bdf, last_bdf);
 
     for ( bdf = first_bdf; bdf <= last_bdf; bdf++ )
-        add_ivrs_mapping_entry(bdf, bdf, range->start.header.data_setting,
+        add_ivrs_mapping_entry(bdf, bdf, range->start.header.data_setting, 0,
                                false, iommu);
 
     return dev_length;
@@ -580,7 +581,7 @@ static u16 __init parse_ivhd_device_alias(
 
     AMD_IOMMU_DEBUG(" Dev_Id Alias: %#x\n", alias_id);
 
-    add_ivrs_mapping_entry(bdf, alias_id, alias->header.data_setting, true,
+    add_ivrs_mapping_entry(bdf, alias_id, alias->header.data_setting, 0, true,
                            iommu);
 
     return dev_length;
@@ -636,7 +637,7 @@ static u16 __init parse_ivhd_device_alias_range(
 
     for ( bdf = first_bdf; bdf <= last_bdf; bdf++ )
         add_ivrs_mapping_entry(bdf, alias_id, range->alias.header.data_setting,
-                               true, iommu);
+                               0, true, iommu);
 
     return dev_length;
 }
@@ -661,7 +662,8 @@ static u16 __init parse_ivhd_device_extended(
         return 0;
     }
 
-    add_ivrs_mapping_entry(bdf, bdf, ext->header.data_setting, false, iommu);
+    add_ivrs_mapping_entry(bdf, bdf, ext->header.data_setting,
+                           ext->extended_data, false, iommu);
 
     return dev_length;
 }
@@ -708,7 +710,7 @@ static u16 __init parse_ivhd_device_extended_range(
 
     for ( bdf = first_bdf; bdf <= last_bdf; bdf++ )
         add_ivrs_mapping_entry(bdf, bdf, range->extended.header.data_setting,
-                               false, iommu);
+                               range->extended.extended_data, false, iommu);
 
     return dev_length;
 }
@@ -800,7 +802,7 @@ static u16 __init parse_ivhd_device_special(
 
     AMD_IOMMU_DEBUG("IVHD Special: %pp variety %#x handle %#x\n",
                     &PCI_SBDF2(seg, bdf), special->variety, special->handle);
-    add_ivrs_mapping_entry(bdf, bdf, special->header.data_setting, true,
+    add_ivrs_mapping_entry(bdf, bdf, special->header.data_setting, 0, true,
                            iommu);
 
     switch ( special->variety )
diff --git a/xen/drivers/passthrough/amd/pci_amd_iommu.c 
b/xen/drivers/passthrough/amd/pci_amd_iommu.c
index 28f45e3fac..45d16b731f 100644
--- a/xen/drivers/passthrough/amd/pci_amd_iommu.c
+++ b/xen/drivers/passthrough/amd/pci_amd_iommu.c
@@ -105,6 +105,7 @@ static int __must_check amd_iommu_setup_domain_device(
     int req_id, valid = 1, rc;
     u8 bus = pdev->bus;
     struct domain_iommu *hd = dom_iommu(domain);
+    const struct ivrs_mappings *ivrs_dev;
 
     if ( QUARANTINE_SKIP(domain) )
         return 0;
@@ -122,20 +123,18 @@ static int __must_check amd_iommu_setup_domain_device(
     req_id = get_dma_requestor_id(iommu->seg, PCI_BDF2(bus, devfn));
     table = iommu->dev_table.buffer;
     dte = &table[req_id];
+    ivrs_dev = &get_ivrs_mappings(iommu->seg)[req_id];
 
     spin_lock_irqsave(&iommu->lock, flags);
 
     if ( !dte->v || !dte->tv )
     {
-        const struct ivrs_mappings *ivrs_dev;
-
         /* bind DTE to domain page-tables */
         amd_iommu_set_root_page_table(
             dte, page_to_maddr(hd->arch.amd.root_table),
             domain->domain_id, hd->arch.amd.paging_mode, valid);
 
         /* Undo what amd_iommu_disable_domain_device() may have done. */
-        ivrs_dev = &get_ivrs_mappings(iommu->seg)[req_id];
         if ( dte->it_root )
         {
             dte->int_ctl = IOMMU_DEV_TABLE_INT_CONTROL_TRANSLATED;
@@ -146,6 +145,7 @@ static int __must_check amd_iommu_setup_domain_device(
         dte->sys_mgt = MASK_EXTR(ivrs_dev->device_flags, 
ACPI_IVHD_SYSTEM_MGMT);
 
         if ( pci_ats_device(iommu->seg, bus, pdev->devfn) &&
+             !ivrs_dev->block_ats &&
              iommu_has_cap(iommu, PCI_CAP_IOTLB_SHIFT) )
             dte->i = ats_enabled;
 
@@ -166,6 +166,8 @@ static int __must_check amd_iommu_setup_domain_device(
     ASSERT(pcidevs_locked());
 
     if ( pci_ats_device(iommu->seg, bus, pdev->devfn) &&
+         !ivrs_dev->block_ats &&
+         iommu_has_cap(iommu, PCI_CAP_IOTLB_SHIFT) &&
          !pci_ats_enabled(iommu->seg, bus, pdev->devfn) )
     {
         if ( devfn == pdev->devfn )
diff --git a/xen/include/acpi/actbl2.h b/xen/include/acpi/actbl2.h
index 4252c90a3f..2ad08ea467 100644
--- a/xen/include/acpi/actbl2.h
+++ b/xen/include/acpi/actbl2.h
@@ -851,7 +851,7 @@ struct acpi_ivrs_device8b {
 
 /* Values for extended_data above */
 
-#define ACPI_IVHD_ATS_DISABLED      (1<<31)
+#define ACPI_IVHD_ATS_DISABLED      (1u << 31)
 
 /* Type 72: 8-byte device entry */
 
--
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