[xen staging] AMD/IOMMU: check / convert IVMD ranges for being / to be reserved

[patchbot@xxxxxxx]

commit ed6c77ebf0c1f865b45596c3e793fe87160251a6
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Wed Sep 22 16:14:19 2021 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Sep 22 16:14:19 2021 +0200

    AMD/IOMMU: check / convert IVMD ranges for being / to be reserved
    
    While the specification doesn't say so, just like for VT-d's RMRRs no
    good can come from these ranges being e.g. conventional RAM or entirely
    unmarked and hence usable for placing e.g. PCI device BARs. Check
    whether they are, and put in some limited effort to convert to reserved.
    (More advanced logic can be added if actual problems are found with this
    simplistic variant.)
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Paul Durrant <paul@xxxxxxx>
---
 xen/drivers/passthrough/amd/iommu_acpi.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/xen/drivers/passthrough/amd/iommu_acpi.c 
b/xen/drivers/passthrough/amd/iommu_acpi.c
index 2fdebd2d74..bc3c946fe5 100644
--- a/xen/drivers/passthrough/amd/iommu_acpi.c
+++ b/xen/drivers/passthrough/amd/iommu_acpi.c
@@ -384,6 +384,38 @@ static int __init parse_ivmd_block(const struct 
acpi_ivrs_memory *ivmd_block)
     AMD_IOMMU_DEBUG("IVMD Block: type %#x phys %#lx len %#lx\n",
                     ivmd_block->header.type, start_addr, mem_length);
 
+    if ( !e820_all_mapped(base, limit + PAGE_SIZE, E820_RESERVED) )
+    {
+        paddr_t addr;
+
+        AMD_IOMMU_DEBUG("IVMD: [%lx,%lx) is not (entirely) in reserved 
memory\n",
+                        base, limit + PAGE_SIZE);
+
+        for ( addr = base; addr <= limit; addr += PAGE_SIZE )
+        {
+            unsigned int type = page_get_ram_type(maddr_to_mfn(addr));
+
+            if ( type == RAM_TYPE_UNKNOWN )
+            {
+                if ( e820_add_range(&e820, addr, addr + PAGE_SIZE,
+                                    E820_RESERVED) )
+                    continue;
+                AMD_IOMMU_DEBUG("IVMD Error: Page at %lx couldn't be 
reserved\n",
+                                addr);
+                return -EIO;
+            }
+
+            /* Types which won't be handed out are considered good enough. */
+            if ( !(type & (RAM_TYPE_RESERVED | RAM_TYPE_ACPI |
+                           RAM_TYPE_UNUSABLE)) )
+                continue;
+
+            AMD_IOMMU_DEBUG("IVMD Error: Page at %lx can't be converted\n",
+                            addr);
+            return -EIO;
+        }
+    }
+
     if ( ivmd_block->header.flags & ACPI_IVMD_EXCLUSION_RANGE )
         exclusion = true;
     else if ( ivmd_block->header.flags & ACPI_IVMD_UNITY )
--
generated by git-patchbot for /home/xen/git/xen.git#staging