On 26/03/2020 15:24, Alexandru Elisei wrote:
> A vesa device is used by the SDL, GTK or VNC framebuffers. Don't allow the
> user to specify more than one of these options because kvmtool will create
> identical devices and bad things will happen:
>
> $ ./lkvm run -c2 -m2048 -k bzImage --sdl --gtk
> # lkvm run -k bzImage -m 2048 -c 2 --name guest-10159
> Error: device region [d0000000-d012bfff] would overlap device region [d0000000-d012bfff]
> *** Error in `./lkvm': free(): invalid pointer: 0x00007fad78002e40 ***
> *** Error in `./lkvm': free(): invalid pointer: 0x00007fad78002e40 ***
> *** Error in `./lkvm': free(): invalid pointer: 0x00007fad78002e40 ***
> ======= Backtrace: =========
> ======= Backtrace: =========
> /lib/x86_64-linux-gnu/libc.so.6(+0x777e5)[0x7fae0ed447e5]
> ======= Backtrace: =========
> /lib/x86_64-linux-gnu/libc.so.6/lib/x86_64-linux-gnu/libc.so.6(+0x8037a)[0x7fae0ed4d37a]
> (+0x777e5)[0x7fae0ed447e5]
> /lib/x86_64-linux-gnu/libc.so.6(+0x777e5)[0x7fae0ed447e5]
> /lib/x86_64-linux-gnu/libc.so.6(+0x8037a)[0x7fae0ed4d37a]
> /lib/x86_64-linux-gnu/libc.so.6(cfree+0x4c)[0x7fae0ed5153c]
> *** Error in `./lkvm': free(): invalid pointer: 0x00007fad78002e40 ***
> /lib/x86_64-linux-gnu/libglib-2.0.so.0(g_string_free+0x3b)[0x7fae0f814dab]
> /lib/x86_64-linux-gnu/libglib-2.0.so.0(g_string_free+0x3b)[0x7fae0f814dab]
> /usr/lib/x86_64-linux-gnu/libgtk-3.so.0(+0x21121c)[0x7fae1023321c]
> /usr/lib/x86_64-linux-gnu/libgtk-3.so.0(+0x21121c)[0x7fae1023321c]
> ======= Backtrace: =========
> Aborted (core dumped)
>
> The vesa device is explicitly created during the initialization phase of
> the above framebuffers. Remove the superfluous check for their existence.
>
Not really happy about this pointer comparison, but I don't see a better
way, and it's surely good enough for that purpose.
> Signed-off-by: Alexandru Elisei <alexandru.elisei@xxxxxxx>
Reviewed-by: Andre Przywara <andre.przywara@xxxxxxx>
Cheers,
Andre
> ---
> hw/vesa.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/hw/vesa.c b/hw/vesa.c
> index dd59a112330b..8071ad153f27 100644
> --- a/hw/vesa.c
> +++ b/hw/vesa.c
> @@ -61,8 +61,11 @@ struct framebuffer *vesa__init(struct kvm *kvm)
> BUILD_BUG_ON(!is_power_of_two(VESA_MEM_SIZE));
> BUILD_BUG_ON(VESA_MEM_SIZE < VESA_BPP/8 * VESA_WIDTH * VESA_HEIGHT);
>
> - if (!kvm->cfg.vnc && !kvm->cfg.sdl && !kvm->cfg.gtk)
> - return NULL;
> + if (device__find_dev(vesa_device.bus_type, vesa_device.dev_num) == &vesa_device) {
> + r = -EEXIST;
> + goto out_error;
> + }
> +
> vesa_base_addr = pci_get_io_port_block(PCI_IO_SIZE);
> r = ioport__register(kvm, vesa_base_addr, &vesa_io_ops, PCI_IO_SIZE, NULL);
> if (r < 0)
>
