From df07a8f8cb743e0ff86346bcb49fe09240e4be6c Mon Sep 17 00:00:00 2001 From: Andrew Melnychenko Date: Wed, 9 Jun 2021 12:58:43 +0300 Subject: [PATCH] virtio-pci: Changed return values for "notify", "device" and "isr" read. At some point, after unplugging virtio-pci the virtio device may be unrealised, but the memory regions may be present in flatview. So, it's a possible situation when memory region's callbacks are called for "unplugged" device. Previous two patches made sure this case does not cause QEMU to crash. This patch adds check for "notify" memory region. Now reads will return "-1" if a virtio device is not present on a virtio bus. Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1938042 Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1743098 Signed-off-by: Andrew Melnychenko Message-Id: <20210609095843.141378-4-andrew@daynix.com> Reviewed-by: Stefano Garzarella Reviewed-by: Raphael Norwitz Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/virtio/virtio-pci.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c index c0d9c47df7d4..433060ac0281 100644 --- a/hw/virtio/virtio-pci.c +++ b/hw/virtio/virtio-pci.c @@ -1349,6 +1349,11 @@ static void virtio_pci_common_write(void *opaque, hwaddr addr, static uint64_t virtio_pci_notify_read(void *opaque, hwaddr addr, unsigned size) { + VirtIOPCIProxy *proxy = opaque; + if (virtio_bus_get_device(&proxy->bus) == NULL) { + return UINT64_MAX; + } + return 0; } @@ -1386,7 +1391,7 @@ static uint64_t virtio_pci_isr_read(void *opaque, hwaddr addr, uint64_t val; if (vdev == NULL) { - return 0; + return UINT64_MAX; } val = qatomic_xchg(&vdev->isr, 0); @@ -1407,7 +1412,7 @@ static uint64_t virtio_pci_device_read(void *opaque, hwaddr addr, uint64_t val; if (vdev == NULL) { - return 0; + return UINT64_MAX; } switch (size) {