Blue Swirl <blauwir...@gmail.com> writes:
> Allow failure with vmware_vga device creation and use standard
> VGA instead.
>
> Signed-off-by: Blue Swirl <blauwir...@gmail.com>
> ---
> hw/mips_malta.c | 6 +++++-
> hw/pc.c | 11 ++++++++---
> hw/vmware_vga.h | 11 +++++++++--
> 3 files changed, 22 insertions(+), 6 deletions(-)
>
> diff --git a/hw/mips_malta.c b/hw/mips_malta.c
> index 2d3f242..930c51c 100644
> --- a/hw/mips_malta.c
> +++ b/hw/mips_malta.c
> @@ -957,7 +957,11 @@ void mips_malta_init (ram_addr_t ram_size,
> if (cirrus_vga_enabled) {
> pci_cirrus_vga_init(pci_bus);
> } else if (vmsvga_enabled) {
> - pci_vmsvga_init(pci_bus);
> + if (!pci_vmsvga_init(pci_bus)) {
> + fprintf(stderr, "Warning: vmware_vga not available,"
> + " using standard VGA instead\n");
> + pci_vga_init(pci_bus);
> + }
> } else if (std_vga_enabled) {
> pci_vga_init(pci_bus);
> }
> diff --git a/hw/pc.c b/hw/pc.c
> index 4dfdc0b..fcee09a 100644
> --- a/hw/pc.c
> +++ b/hw/pc.c
> @@ -1053,10 +1053,15 @@ void pc_vga_init(PCIBus *pci_bus)
> isa_cirrus_vga_init();
> }
> } else if (vmsvga_enabled) {
> - if (pci_bus)
> - pci_vmsvga_init(pci_bus);
> - else
> + if (pci_bus) {
> + if (!pci_vmsvga_init(pci_bus)) {
> + fprintf(stderr, "Warning: vmware_vga not available,"
> + " using standard VGA instead\n");
I don't like "vmware_vga" here. The command line option that makes us
go here is spelled "-vga vmware", and the qdev is called "vmware-svga".
What about "-vga vmware is not available"?
> + pci_vga_init(pci_bus);
> + }
> + } else {
> fprintf(stderr, "%s: vmware_vga: no PCI bus\n", __FUNCTION__);
> + }
> #ifdef CONFIG_SPICE
> } else if (qxl_enabled) {
> if (pci_bus)
> diff --git a/hw/vmware_vga.h b/hw/vmware_vga.h
> index e7bcb22..5132573 100644
> --- a/hw/vmware_vga.h
> +++ b/hw/vmware_vga.h
> @@ -4,9 +4,16 @@
> #include "qemu-common.h"
>
> /* vmware_vga.c */
> -static inline void pci_vmsvga_init(PCIBus *bus)
> +static inline bool pci_vmsvga_init(PCIBus *bus)
> {
> - pci_create_simple(bus, -1, "vmware-svga");
> + PCIDevice *dev;
> +
> + dev = pci_try_create(bus, -1, "vmware-svga");
> + if (!dev || qdev_init(&dev->qdev) < 0) {
> + return false;
> + } else {
> + return true;
> + }
> }
>
> #endif
Two failure modes:
* pci_try_create() fails, which can happen only if no such qdev
"vmware-svga" exists.
* qdev_init() fails.
The caller can't distinguish between the two, and assumes any failure
must be the former.
The assumption is actually correct, because pci_vmsvga_initfn() never
fails, and thus qdev_init() never fails. Brittle.
pci_vmsvga_init() is a convenience function for board setup code. Why
not make it more convenient and concentrate the error handling there
rather than duplicating it in each caller?
Nice side effect: no need to conflate the failure modes, no need for the
brittle assumption.
