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Re: [Qemu-devel] [PATCH v2] xenfb: remove xen_init_display "temporary" h
From: |
Paul Durrant |
Subject: |
Re: [Qemu-devel] [PATCH v2] xenfb: remove xen_init_display "temporary" hack |
Date: |
Thu, 29 Jun 2017 08:24:41 +0000 |
> -----Original Message-----
> From: Stefano Stabellini [mailto:address@hidden
> Sent: 28 June 2017 19:37
> To: address@hidden; address@hidden
> Cc: address@hidden; address@hidden; Anthony Perard
> <address@hidden>; address@hidden; Paul Durrant
> <address@hidden>
> Subject: [PATCH v2] xenfb: remove xen_init_display "temporary" hack
>
> Initialize xenfb properly, as all other backends, from its own
> "initialise" function.
>
> Signed-off-by: Stefano Stabellini <address@hidden>
>
> ---
> Changes in v2:
> - remove xen_init_display from xen_backend.h
> - handle cases where vkbd is missing
>
> diff --git a/hw/display/xenfb.c b/hw/display/xenfb.c
> index e76c0d8..3b0168b 100644
> --- a/hw/display/xenfb.c
> +++ b/hw/display/xenfb.c
> @@ -71,7 +71,6 @@ struct XenFB {
> int fbpages;
> int feature_update;
> int bug_trigger;
> - int have_console;
> int do_resize;
>
> struct {
> @@ -80,6 +79,7 @@ struct XenFB {
> int up_count;
> int up_fullscreen;
> };
> +static const GraphicHwOps xenfb_ops;
>
> /* -------------------------------------------------------------------- */
>
> @@ -855,6 +855,8 @@ static int fb_init(struct XenDevice *xendev)
> static int fb_initialise(struct XenDevice *xendev)
> {
> struct XenFB *fb = container_of(xendev, struct XenFB, c.xendev);
> + struct XenDevice *xin;
> + struct XenInput *in;
I think the scope of 'in' can be limited to the 'else' clause where it is used
below.
> struct xenfb_page *fb_page;
> int videoram;
> int rc;
> @@ -877,16 +879,16 @@ static int fb_initialise(struct XenDevice *xendev)
> if (rc != 0)
> return rc;
>
> -#if 0 /* handled in xen_init_display() for now */
> - if (!fb->have_console) {
> - fb->c.ds = graphic_console_init(xenfb_update,
> - xenfb_invalidate,
> - NULL,
> - NULL,
> - fb);
> - fb->have_console = 1;
> + fb->c.con = graphic_console_init(NULL, 0, &xenfb_ops, fb);
> +
> + xin = xen_pv_find_xendev("vkbd", xen_domid, 0);
> + if (xin == NULL) {
> + xen_pv_printf(xendev, 1, "xenfb is up, but vkbd is not present\n");
> + } else {
> + in = container_of(xin, struct XenInput, c.xendev);
> + in->c.con = fb->c.con;
I notice that in->c.con is tested in input_initialise() and it will fail if
NULL, so there is an inherent race between the frontends and also processing of
xenstore watches. That seems a little fragile at best, but the dependency of
input_initialise() on in->c.con is also somewhat bogus as the vkbd backend is
created for xenfv machine types whereas xenfb is only there for xenpv machine
types. I think this needs to be fixed before xenfb can be relied on to
initialize correctly in all circumstances.
Paul
> + xen_be_check_state(xin);
> }
> -#endif
>
> if (xenstore_read_fe_int(xendev, "feature-update", &fb-
> >feature_update) == -1)
> fb->feature_update = 0;
> @@ -972,42 +974,3 @@ static const GraphicHwOps xenfb_ops = {
> .gfx_update = xenfb_update,
> .update_interval = xenfb_update_interval,
> };
> -
> -/*
> - * FIXME/TODO: Kill this.
> - * Temporary needed while DisplayState reorganization is in flight.
> - */
> -void xen_init_display(int domid)
> -{
> - struct XenDevice *xfb, *xin;
> - struct XenFB *fb;
> - struct XenInput *in;
> - int i = 0;
> -
> -wait_more:
> - i++;
> - main_loop_wait(true);
> - xfb = xen_pv_find_xendev("vfb", domid, 0);
> - xin = xen_pv_find_xendev("vkbd", domid, 0);
> - if (!xfb || !xin) {
> - if (i < 256) {
> - usleep(10000);
> - goto wait_more;
> - }
> - xen_pv_printf(NULL, 1, "displaystate setup failed\n");
> - return;
> - }
> -
> - /* vfb */
> - fb = container_of(xfb, struct XenFB, c.xendev);
> - fb->c.con = graphic_console_init(NULL, 0, &xenfb_ops, fb);
> - fb->have_console = 1;
> -
> - /* vkbd */
> - in = container_of(xin, struct XenInput, c.xendev);
> - in->c.con = fb->c.con;
> -
> - /* retry ->init() */
> - xen_be_check_state(xin);
> - xen_be_check_state(xfb);
> -}
> diff --git a/hw/xenpv/xen_machine_pv.c b/hw/xenpv/xen_machine_pv.c
> index 79aef4e..31d2f25 100644
> --- a/hw/xenpv/xen_machine_pv.c
> +++ b/hw/xenpv/xen_machine_pv.c
> @@ -94,9 +94,6 @@ static void xen_init_pv(MachineState *machine)
>
> /* config cleanup hook */
> atexit(xen_config_cleanup);
> -
> - /* setup framebuffer */
> - xen_init_display(xen_domid);
> }
>
> static void xenpv_machine_init(MachineClass *mc)
> diff --git a/include/hw/xen/xen_backend.h
> b/include/hw/xen/xen_backend.h
> index 852c2ea..8a6fbcb 100644
> --- a/include/hw/xen/xen_backend.h
> +++ b/include/hw/xen/xen_backend.h
> @@ -55,8 +55,6 @@ extern struct XenDevOps xen_netdev_ops; /*
> xen_nic.c */
> extern struct XenDevOps xen_usb_ops; /* xen-usb.c */
> #endif
>
> -void xen_init_display(int domid);
> -
> /* configuration (aka xenbus setup) */
> void xen_config_cleanup(void);
> int xen_config_dev_blk(DriveInfo *disk);