File 5f8ed6b0-AMD-IOMMU-suitably-order-DTE-mods.patch of Package xen

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File 5f8ed6b0-AMD-IOMMU-suitably-order-DTE-mods.patch of Package xen (Revision d35458d4f796b7ecd4d4063f9ee4aca9)

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# Commit 0514a3a25fb9ebff5d75cc8f00a9229385300858
# Date 2020-10-20 14:23:12 +0200
# Author Jan Beulich <jbeulich@suse.com>
# Committer Jan Beulich <jbeulich@suse.com>
AMD/IOMMU: ensure suitable ordering of DTE modifications

DMA and interrupt translation should be enabled only after other
applicable DTE fields have been written. Similarly when disabling
translation or when moving a device between domains, translation should
first be disabled, before other entry fields get modified. Note however
that the "moving" aspect doesn't apply to the interrupt remapping side,
as domain specifics are maintained in the IRTEs here, not the DTE. We
also never disable interrupt remapping once it got enabled for a device
(the respective argument passed is always the immutable iommu_intremap).

This is part of XSA-347.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Paul Durrant <paul@xen.org>

--- a/xen/drivers/passthrough/amd/iommu_map.c
+++ b/xen/drivers/passthrough/amd/iommu_map.c
@@ -103,11 +103,18 @@ void amd_iommu_set_root_page_table(struc
                                    uint64_t root_ptr, uint16_t domain_id,
                                    uint8_t paging_mode, bool valid)
 {
+    if ( valid || dte->v )
+    {
+        dte->tv = false;
+        dte->v = true;
+        smp_wmb();
+    }
     dte->domain_id = domain_id;
     dte->pt_root = paddr_to_pfn(root_ptr);
     dte->iw = true;
     dte->ir = true;
     dte->paging_mode = paging_mode;
+    smp_wmb();
     dte->tv = true;
     dte->v = valid;
 }
@@ -130,6 +137,7 @@ void amd_iommu_set_intremap_table(
     }
 
     dte->ig = false; /* unmapped interrupts result in i/o page faults */
+    smp_wmb();
     dte->iv = valid;
 }
 
--- a/xen/drivers/passthrough/amd/pci_amd_iommu.c
+++ b/xen/drivers/passthrough/amd/pci_amd_iommu.c
@@ -117,7 +117,10 @@ static void amd_iommu_setup_domain_devic
         /* 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;
+            smp_wmb();
+        }
         dte->iv = iommu_intremap;
         dte->ex = ivrs_dev->dte_allow_exclusion;
         dte->sys_mgt = MASK_EXTR(ivrs_dev->device_flags, ACPI_IVHD_SYSTEM_MGMT);

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File 5f8ed6b0-AMD-IOMMU-suitably-order-DTE-mods.patch of Package xen (Revision d35458d4f796b7ecd4d4063f9ee4aca9)

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