From: Alexey Kardashevskiy <aik@ozlabs.ru>
Date: Thu, 7 May 2015 05:33:28 +0000 (+1000)
Subject: spapr_iommu: Disable in-kernel IOMMU tables for >4GB windows
X-Git-Url: https://repo.jachan.dev/qemu.git/commitdiff_plain/12fd28535891572be7aaf862a03019257dafa425

spapr_iommu: Disable in-kernel IOMMU tables for >4GB windows

The existing KVM_CREATE_SPAPR_TCE ioctl only support 4G windows max as
the window size parameter to the kernel ioctl() is 32-bit so
there's no way of expressing a TCE window > 4GB.

We are going to add huge DMA windows support so this will create small
window and unexpectedly fail later.

This disables KVM_CREATE_SPAPR_TCE for windows bigger that 4GB.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
---

diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c
index f3990fdc32..e19bf89929 100644
--- a/hw/ppc/spapr_iommu.c
+++ b/hw/ppc/spapr_iommu.c
@@ -126,11 +126,11 @@ static MemoryRegionIOMMUOps spapr_iommu_ops = {
 static int spapr_tce_table_realize(DeviceState *dev)
 {
     sPAPRTCETable *tcet = SPAPR_TCE_TABLE(dev);
+    uint64_t window_size = (uint64_t)tcet->nb_table << tcet->page_shift;
 
-    if (kvm_enabled()) {
+    if (kvm_enabled() && !(window_size >> 32)) {
         tcet->table = kvmppc_create_spapr_tce(tcet->liobn,
-                                              tcet->nb_table <<
-                                              tcet->page_shift,
+                                              window_size,
                                               &tcet->fd,
                                               tcet->vfio_accel);
     }