[Spice-devel] [spice-protocol PATCH v2 0.12.2 1/2] qxl_dev.h: add client monitors configuration notification to guest

[Hans de Goede]

Hi,

On 09/11/2012 04:35 PM, Alon Levy wrote:
> So far we have used the agent to notify the guest of a request to change
> the monitors configurations (heads) on the qxl device. This patch introduces
> a new interrupt and new fields in the qxl rom to notify the guest about
> a new request, similarly to how physical hardware notifies the driver.
>
> To avoid overwriting the rom while the guest is reading it there is a
> client_monitors_config_updating field in ROM. The update protocol is:
>
> qemu:
>    (1) set QXLRom::client_monitors_config_updating
>    (2) fill QXLRom::client_monitors_config
>    (3) raise QXL_INTERRUPT_CLIENT_MONITORS_CONFIG
>    (4) clear QXLRom::client_monitors_config_updating
>
> guest:
>    (1) clear QXL_INTERRUPT_CLIENT_MONITORS_CONFIG bit in irq status
>    (2) wait until QXLRom::client_monitors_config_updating is clear
>    (3) parse QXLRom::client_monitors_config
>    (4) check that QXLRom::client_monitors_Config_updating is clear
>        (a) when set, goto (1)
>    (5) check QXL_INTERRUPT_CLIENT_MONITORS_CONFIG bit in irq status
>        (a) when set, goto (1)
>        (b) when clear we are done
>

This seems very complicated how about:

qemu:
    (1) fill QXLRom::client_monitors_config, including a crc32 of the data
    (2) raise QXL_INTERRUPT_CLIENT_MONITORS_CONFIG

guest on interrupt:
    (1) clear QXL_INTERRUPT_CLIENT_MONITORS_CONFIG bit in irq status
    (2) read QXLRom::client_monitors_config
    (3) (verify-crc)? done : goto 2

That seems more straight-forward to me.

Regards,

Hans