[PATCH 2/3] device-assignment: Always use slow mapping for PCI option ROM

[Alex Williamson <alex.williamson@redhat.com>]

KVM doesn't support read-only mappings for MMIO space.  Performance isn't
an issue for the option ROM mapping, so always use slow mapping.  kvm.git
cset b4f8c249 will make kvm hang with a "Bad address" fault without this.
We can also then drop the extraneous mprotects since the guest has no way
to write to these regions.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---

 hw/device-assignment.c |    8 ++------
 1 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/hw/device-assignment.c b/hw/device-assignment.c
index c26ff6d..0e82a16 100644
--- a/hw/device-assignment.c
+++ b/hw/device-assignment.c
@@ -541,6 +541,8 @@ static int assigned_dev_register_regions(PCIRegion *io_regions,
             /* map physical memory */
             pci_dev->v_addrs[i].e_physbase = cur_region->base_addr;
             if (i == PCI_ROM_SLOT) {
+                /* KVM doesn't support read-only mappings, use slow map */
+                slow_map = 1;
                 pci_dev->v_addrs[i].u.r_virtbase =
                     mmap(NULL,
                          cur_region->size,
@@ -566,8 +568,6 @@ static int assigned_dev_register_regions(PCIRegion *io_regions,
             if (i == PCI_ROM_SLOT) {
                 memset(pci_dev->v_addrs[i].u.r_virtbase, 0,
                        (cur_region->size + 0xFFF) & 0xFFFFF000);
-                mprotect(pci_dev->v_addrs[PCI_ROM_SLOT].u.r_virtbase,
-                         (cur_region->size + 0xFFF) & 0xFFFFF000, PROT_READ);
             }
 
             pci_dev->v_addrs[i].r_size = cur_region->size;
@@ -1691,12 +1691,8 @@ static void assigned_dev_load_option_rom(AssignedDevice *dev)
     /* Copy ROM contents into the space backing the ROM BAR */
     if (dev->v_addrs[PCI_ROM_SLOT].r_size >= size &&
         dev->v_addrs[PCI_ROM_SLOT].u.r_virtbase) {
-        mprotect(dev->v_addrs[PCI_ROM_SLOT].u.r_virtbase,
-                 size, PROT_READ | PROT_WRITE);
         memcpy(dev->v_addrs[PCI_ROM_SLOT].u.r_virtbase,
                buf, size);
-        mprotect(dev->v_addrs[PCI_ROM_SLOT].u.r_virtbase,
-                 size, PROT_READ);
     }
 
     free(buf);