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[Qemu-devel] [PULL 1/1] vfio/pci: do not set the PCIDevice 'has_rom' att

From: Alex Williamson
Subject: [Qemu-devel] [PULL 1/1] vfio/pci: do not set the PCIDevice 'has_rom' attribute
Date: Wed, 11 Jul 2018 13:56:13 -0600
User-agent: StGit/0.18-136-gffd7

From: Cédric Le Goater <address@hidden>

PCI devices needing a ROM allocate an optional MemoryRegion with
pci_add_option_rom(). pci_del_option_rom() does the cleanup when the
device is destroyed. The only action taken by this routine is to call
vmstate_unregister_ram() which clears the id string of the optional
ROM RAMBlock and now, also flags the RAMBlock as non-migratable. This
was recently added by commit b895de502717 ("migration: discard
non-migratable RAMBlocks"), .

VFIO devices do their own loading of the PCI option ROM in
vfio_pci_size_rom(). The memory region is switched to an I/O region
and the PCI attribute 'has_rom' is set but the RAMBlock of the ROM
region is not allocated. When the associated PCI device is deleted,
pci_del_option_rom() calls vmstate_unregister_ram() which tries to
flag a NULL RAMBlock, leading to a SEGV.

It seems that 'has_rom' was set to have memory_region_destroy()
called, but since commit 469b046ead06 ("memory: remove
memory_region_destroy") this is not necessary anymore as the
MemoryRegion is freed automagically.

Remove the PCIDevice 'has_rom' attribute setting in vfio.

Fixes: b895de502717 ("migration: discard non-migratable RAMBlocks")
Signed-off-by: Cédric Le Goater <address@hidden>
Reviewed-by: Michael S. Tsirkin <address@hidden>
Signed-off-by: Alex Williamson <address@hidden>
 hw/vfio/pci.c |    1 -
 1 file changed, 1 deletion(-)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index a1577dea7fdb..6cbb8fa0549d 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -990,7 +990,6 @@ static void vfio_pci_size_rom(VFIOPCIDevice *vdev)
     pci_register_bar(&vdev->pdev, PCI_ROM_SLOT,
                      PCI_BASE_ADDRESS_SPACE_MEMORY, &vdev->pdev.rom);
-    vdev->pdev.has_rom = true;
     vdev->rom_read_failed = false;

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