From 324a0ffc5140c4ece5b720708da2c673a8d1b9cc Mon Sep 17 00:00:00 2001 From: Thomas Huth Date: Tue, 1 Oct 2019 06:02:58 +0100 Subject: [PATCH 12/22] s390: PCI: fix IOMMU region init RH-Author: Thomas Huth Message-id: <20191001060258.28206-2-thuth@redhat.com> Patchwork-id: 90929 O-Subject: [RHEL-8.2.0/RHEL-8.1.z qemu-kvm PATCH 1/1] s390: PCI: fix IOMMU region init Bugzilla: 1754643 RH-Acked-by: Jens Freimann RH-Acked-by: David Hildenbrand RH-Acked-by: Maxim Levitsky From: Matthew Rosato 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") Reviewed-by: Pierre Morel Reported-by: Boris Fiuczynski Tested-by: Boris Fiuczynski Reported-by: Stefan Zimmerman Signed-off-by: Matthew Rosato Message-Id: <1569507036-15314-1-git-send-email-mjrosato@linux.ibm.com> Signed-off-by: Christian Borntraeger (cherry picked from commit 7df1dac5f1c85312474df9cb3a8fcae72303da62) Signed-off-by: Danilo C. L. de Paula --- 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 383b3e7..069e152 100644 --- a/hw/s390x/s390-pci-bus.c +++ b/hw/s390x/s390-pci-bus.c @@ -691,10 +691,15 @@ 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); -- 1.8.3.1