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From 85d3fdbf408b0d96ff27c38d09770685c6bac4ec Mon Sep 17 00:00:00 2001
From: "" <>
Date: Mon, 7 Jan 2019 17:02:15 +0000
Subject: [PATCH 14/22] vfio/pci: do not set the PCIDevice 'has_rom' attribute
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Message-id: <>
Patchwork-id: 83888
O-Subject: [RHEL8.0 qemu-kvm PATCH v7 02/10] vfio/pci: do not set the PCIDevice 'has_rom' attribute
Bugzilla: 1539285
RH-Acked-by: Stefan Hajnoczi <>
RH-Acked-by: Dr. David Alan Gilbert <>
RH-Acked-by: Eduardo Habkost <>

From: Cédric Le Goater <>

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 <>
Reviewed-by: Michael S. Tsirkin <>
Signed-off-by: Alex Williamson <>
(cherry picked from commit 26c0ae56386edacc8b0da40264748f59afedb1bb)
Signed-off-by: Paul Lai <>
Signed-off-by: Danilo C. L. de Paula <>
 hw/vfio/pci.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index b463661..ba3a393 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;