virtio_pci_modern: avoid infinite loop in vp_reset() on invalid status

vp_reset() polls device_status in a tight loop, waiting for it to read
back as 0 after the reset write. device_status is read via MMIO from
the common configuration structure, which requires the PCI_COMMAND
Memory Space Enable bit to be set. If that bit is cleared while the
device is bound -- e.g. by writing 0x0000 to PCI_COMMAND (config space
offset 4) -- the MMIO read no longer reaches the device and returns
the bus's synthesized all-ones response instead. Since that value can
never legitimately clear to 0, the loop spins forever and hangs the
caller.

Use VIRTIO_STATUS_ERROR() to recognize such values and bail out of the
poll loop instead of looping indefinitely.

Signed-off-by: Abhin Parekadan Jose <abhinjoses@gmail.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-ID: <20260802174059.4082-3-abhinjoses@gmail.com>

0 files changed, 0 insertions, 0 deletions