File s390-PCI-fix-IOMMU-region-init.patch of Package qemu

Overview Repositories Revisions Requests Users Attributes Meta

File s390-PCI-fix-IOMMU-region-init.patch of Package qemu (Revision 6e3ce658db9b4c549507eef05c4e4865)

Currently displaying revision 6e3ce658db9b4c549507eef05c4e4865 , Show latest

From: Matthew Rosato <mjrosato@linux.ibm.com>
Date: Thu, 26 Sep 2019 10:10:36 -0400
Subject: s390: PCI: fix IOMMU region init

Git-commit: 7df1dac5f1c85312474df9cb3a8fcae72303da62

The fix in dbe9cf606c shrinks the IOMMU memory region to a size
that seems reasonable on the surface, however is actually too
small as it is based against a 0-mapped address space.  This
causes breakage with small guests as they can overrun the IOMMU window.

Let's go back to the prior method of initializing iommu for now.

Fixes: dbe9cf606c ("s390x/pci: Set the iommu region size mpcifc request")
Cc: qemu-stable@nongnu.org
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Reported-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
Tested-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
Reported-by: Stefan Zimmerman <stzi@linux.ibm.com>
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Message-Id: <1569507036-15314-1-git-send-email-mjrosato@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Bruce Rogers <brogers@suse.com>
---
 hw/s390x/s390-pci-bus.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c
index 2c6e084e2c2636b55980799b5837..9a935f22b5b06a67c8fbd7b6abb6 100644
--- a/hw/s390x/s390-pci-bus.c
+++ b/hw/s390x/s390-pci-bus.c
@@ -694,10 +694,15 @@ static const MemoryRegionOps s390_msi_ctrl_ops = {
 
 void s390_pci_iommu_enable(S390PCIIOMMU *iommu)
 {
+    /*
+     * The iommu region is initialized against a 0-mapped address space,
+     * so the smallest IOMMU region we can define runs from 0 to the end
+     * of the PCI address space.
+     */
     char *name = g_strdup_printf("iommu-s390-%04x", iommu->pbdev->uid);
     memory_region_init_iommu(&iommu->iommu_mr, sizeof(iommu->iommu_mr),
                              TYPE_S390_IOMMU_MEMORY_REGION, OBJECT(&iommu->mr),
-                             name, iommu->pal - iommu->pba + 1);
+                             name, iommu->pal + 1);
     iommu->enabled = true;
     memory_region_add_subregion(&iommu->mr, 0, MEMORY_REGION(&iommu->iommu_mr));
     g_free(name);

Places

File s390-PCI-fix-IOMMU-region-init.patch of Package qemu (Revision 6e3ce658db9b4c549507eef05c4e4865)

Places