[Xen-changelog] [xen staging] AMD/IOMMU: pre-fill all DTEs right after table allocation

[patchbot@xxxxxxx]

commit 1b00c16bdfbec98887731a40ea9f377f7dcac405
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Thu Oct 10 09:51:46 2019 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Oct 10 09:51:46 2019 +0200

    AMD/IOMMU: pre-fill all DTEs right after table allocation
    
    Make sure we don't leave any DTEs unexpected requests through which
    would be passed through untranslated. Set V and IV right away (with
    all other fields left as zero), relying on the V and/or IV bits
    getting cleared only by amd_iommu_set_root_page_table() and
    amd_iommu_set_intremap_table() under special pass-through circumstances.
    Switch back to initial settings in amd_iommu_disable_domain_device().
    
    Take the liberty and also make the latter function static, constifying
    its first parameter at the same time, at this occasion.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Release-acked-by: Juergen Gross <jgross@xxxxxxxx>
---
 xen/drivers/passthrough/amd/iommu_init.c    | 22 +++++++++++++++++++---
 xen/drivers/passthrough/amd/pci_amd_iommu.c | 20 ++++++++++++++++----
 2 files changed, 35 insertions(+), 7 deletions(-)

diff --git a/xen/drivers/passthrough/amd/iommu_init.c 
b/xen/drivers/passthrough/amd/iommu_init.c
index badc85fa2b..d50224cbf8 100644
--- a/xen/drivers/passthrough/amd/iommu_init.c
+++ b/xen/drivers/passthrough/amd/iommu_init.c
@@ -1259,12 +1259,28 @@ static int __init amd_iommu_setup_device_table(
 
     if ( !dt )
     {
+        unsigned int size = dt_alloc_size();
+
         /* allocate 'device table' on a 4K boundary */
         dt = IVRS_MAPPINGS_DEVTAB(ivrs_mappings) =
-            allocate_buffer(dt_alloc_size(), "Device Table", true);
+            allocate_buffer(size, "Device Table", false);
+        if ( !dt )
+            return -ENOMEM;
+
+        /*
+         * Prefill every DTE such that all kinds of requests will get aborted.
+         * Besides the two bits set to true below this builds upon
+         * IOMMU_DEV_TABLE_SYS_MGT_DMA_ABORTED,
+         * IOMMU_DEV_TABLE_IO_CONTROL_ABORTED, as well as
+         * IOMMU_DEV_TABLE_INT_CONTROL_ABORTED all being zero, and us also
+         * wanting at least TV, GV, I, and EX set to false.
+         */
+        for ( bdf = 0, size /= sizeof(*dt); bdf < size; ++bdf )
+            dt[bdf] = (struct amd_iommu_dte){
+                          .v = true,
+                          .iv = true,
+                      };
     }
-    if ( !dt )
-        return -ENOMEM;
 
     /* Add device table entries */
     for ( bdf = 0; bdf < ivrs_bdf_entries; bdf++ )
diff --git a/xen/drivers/passthrough/amd/pci_amd_iommu.c 
b/xen/drivers/passthrough/amd/pci_amd_iommu.c
index 8b99d78978..053e7355c4 100644
--- a/xen/drivers/passthrough/amd/pci_amd_iommu.c
+++ b/xen/drivers/passthrough/amd/pci_amd_iommu.c
@@ -267,9 +267,9 @@ static void __hwdom_init amd_iommu_hwdom_init(struct domain 
*d)
     setup_hwdom_pci_devices(d, amd_iommu_add_device);
 }
 
-void amd_iommu_disable_domain_device(struct domain *domain,
-                                     struct amd_iommu *iommu,
-                                     u8 devfn, struct pci_dev *pdev)
+static void amd_iommu_disable_domain_device(const struct domain *domain,
+                                            struct amd_iommu *iommu,
+                                            uint8_t devfn, struct pci_dev 
*pdev)
 {
     struct amd_iommu_dte *table, *dte;
     unsigned long flags;
@@ -284,9 +284,21 @@ void amd_iommu_disable_domain_device(struct domain *domain,
     spin_lock_irqsave(&iommu->lock, flags);
     if ( dte->tv || dte->v )
     {
+        /* See the comment in amd_iommu_setup_device_table(). */
+        dte->int_ctl = IOMMU_DEV_TABLE_INT_CONTROL_ABORTED;
+        smp_wmb();
+        dte->iv = true;
         dte->tv = false;
-        dte->v = false;
+        dte->gv = false;
         dte->i = false;
+        dte->ex = false;
+        dte->sa = false;
+        dte->se = false;
+        dte->sd = false;
+        dte->sys_mgt = IOMMU_DEV_TABLE_SYS_MGT_DMA_ABORTED;
+        dte->ioctl = IOMMU_DEV_TABLE_IO_CONTROL_ABORTED;
+        smp_wmb();
+        dte->v = true;
 
         amd_iommu_flush_device(iommu, req_id);
 
--
generated by git-patchbot for /home/xen/git/xen.git#staging

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