[PATCH] xen/vpci: zero guest-visible BAR addresses to ensure domU asssigns its own

[Ariadne Conill <ariadne@ariadne.space>]

From: Steven Noonan <steven@xxxxxxxxx>

If we just use the host's BAR addresses, the domU might not attempt to
reconfigure the BAR ranges and may never try to map them with the IOMMU.
Zeroing them ensures the guest kernel knows the BARs are not configured
and needs to make its own choices about where to map the BARs.

Signed-off-by: Steven Noonan <steven@xxxxxxxxx>
Signed-off-by: Ariadne Conill <ariadne@ariadne.space>
---
 xen/drivers/vpci/header.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/drivers/vpci/header.c b/xen/drivers/vpci/header.c
index 739a5f610e..852dfd8ae3 100644
--- a/xen/drivers/vpci/header.c
+++ b/xen/drivers/vpci/header.c
@@ -1011,7 +1011,7 @@ int vpci_init_header(struct pci_dev *pdev)
         }
 
         bars[i].addr = addr;
-        bars[i].guest_addr = addr;
+        bars[i].guest_addr = is_hwdom ? addr : 0;
         bars[i].size = size;
         bars[i].prefetchable = val & PCI_BASE_ADDRESS_MEM_PREFETCH;
 
@@ -1034,7 +1034,7 @@ int vpci_init_header(struct pci_dev *pdev)
         rom->type = VPCI_BAR_ROM;
         rom->size = size;
         rom->addr = addr;
-        rom->guest_addr = addr;
+        rom->guest_addr = is_hwdom ? addr : 0;
         header->rom_enabled = pci_conf_read32(pdev->sbdf, rom_reg) &
                               PCI_ROM_ADDRESS_ENABLE;
 
-- 
2.53.0