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[v2] RFC: qxl: allow to specify head limit to qxl driver

Message ID 1434015506-6955-1-git-send-email-fziglio@redhat.com
State New
Headers show

Commit Message

Frediano Ziglio June 11, 2015, 9:38 a.m. UTC 
This patch allow to limit number of heads using qxl driver. By default
qxl driver is not limited on any kind on head use so can decide to use
as much heads.

libvirt has this as a video card parameter (actually set to 1 but not
used). This parameter will allow to limit setting a use can do (which
could be confusing).

This patch rely on some change in spice-protocol which are not still
accepted. See
http://lists.freedesktop.org/archives/spice-devel/2015-June/020221.html.

Signed-off-by: Frediano Ziglio <fziglio@redhat.com>
---
 hw/display/qxl.c | 20 +++++++++++++++-----
 hw/display/qxl.h |  1 +
 2 files changed, 16 insertions(+), 5 deletions(-)

This version change the way limit is set. It came from Gerd Hoffmann
suggestion.

Comments

Frediano Ziglio June 12, 2015, 2:02 p.m. UTC | #1 
> 
> On Do, 2015-06-11 at 10:38 +0100, Frediano Ziglio wrote:
> > libvirt has this as a video card parameter (actually set to 1 but not
> > used). This parameter will allow to limit setting a use can do (which
> > could be confusing).
> 
> Hmm.  So heads is '1' by default but ignored today.  When this starts to
> be actually applied that will break existing multihead setups I suspect.
> 

Yes, unfortunately libvirt always set the default to 1 even if not used by driver.
However the Qemu default (with no parameter) is still unlimited so it's a libvirt issue more then Qemu.

> > This patch rely on some change in spice-protocol which are not still
> > accepted. See
> > http://lists.freedesktop.org/archives/spice-devel/2015-June/020221.html.
> 
> Spice-server changes, right?
> Needs #ifdefs so qemu continues to build with old spice-server versions.
> The spice-server changes need to be upstream first.
> 

Yes, I'll do.

> Also: when we pass on the limit to spice-server anyway spice-server can
> take care to apply the limit both ways and not call the
> ->client_monitors_config() callback with more than $limit monitors.  Has
> the advantage to reduce the test matrix:  Limit either works or doesn't.
> There will be no spice-server/qemu version combination where the limit
> is applied one way only.
> 
>   Gerd
> 

Is always Qemu that decide to apply the limitation, default (even for spice-server) is still unlimited. As Qemu compiled with option on won't run with older version there will never this problem. However I would agree that the patch for Qemu keeping all limits on one place would be smaller.

Frediano
diff mbox

Patch

diff --git a/hw/display/qxl.c b/hw/display/qxl.c
index b220e2d..678fde5 100644
--- a/hw/display/qxl.c
+++ b/hw/display/qxl.c
@@ -272,6 +272,10 @@  static void qxl_spice_monitors_config_async(PCIQXLDevice *qxl, int replay)
                     QXL_COOKIE_TYPE_POST_LOAD_MONITORS_CONFIG,
                     0));
     } else {
+        if (qxl->max_outputs) {
+            spice_qxl_set_monitors_config_limit(&qxl->ssd.qxl,
+                                                qxl->max_outputs);
+        }
         qxl->guest_monitors_config = qxl->ram->monitors_config;
         spice_qxl_monitors_config_async(&qxl->ssd.qxl,
                 qxl->ram->monitors_config,
@@ -992,6 +996,7 @@  static int interface_client_monitors_config(QXLInstance *sin,
     PCIQXLDevice *qxl = container_of(sin, PCIQXLDevice, ssd.qxl);
     QXLRom *rom = memory_region_get_ram_ptr(&qxl->rom_bar);
     int i;
+    unsigned max_outputs = ARRAY_SIZE(rom->client_monitors_config.heads);
 
     if (qxl->revision < 4) {
         trace_qxl_client_monitors_config_unsupported_by_device(qxl->id,
@@ -1014,17 +1019,21 @@  static int interface_client_monitors_config(QXLInstance *sin,
     if (!monitors_config) {
         return 1;
     }
+
+    /* limit number of outputs based on setting limit */
+    if (qxl->max_outputs && qxl->max_outputs <= max_outputs) {
+        max_outputs = qxl->max_outputs;
+    }
+
     memset(&rom->client_monitors_config, 0,
            sizeof(rom->client_monitors_config));
     rom->client_monitors_config.count = monitors_config->num_of_monitors;
     /* monitors_config->flags ignored */
-    if (rom->client_monitors_config.count >=
-            ARRAY_SIZE(rom->client_monitors_config.heads)) {
+    if (rom->client_monitors_config.count >= max_outputs) {
         trace_qxl_client_monitors_config_capped(qxl->id,
                                 monitors_config->num_of_monitors,
-                                ARRAY_SIZE(rom->client_monitors_config.heads));
-        rom->client_monitors_config.count =
-            ARRAY_SIZE(rom->client_monitors_config.heads);
+                                max_outputs);
+        rom->client_monitors_config.count = max_outputs;
     }
     for (i = 0 ; i < rom->client_monitors_config.count ; ++i) {
         VDAgentMonConfig *monitor = &monitors_config->monitors[i];
@@ -2278,6 +2287,7 @@  static Property qxl_properties[] = {
         DEFINE_PROP_UINT32("vram64_size_mb", PCIQXLDevice, vram_size_mb, -1),
         DEFINE_PROP_UINT32("vgamem_mb", PCIQXLDevice, vgamem_size_mb, 16),
         DEFINE_PROP_INT32("surfaces", PCIQXLDevice, ssd.num_surfaces, 1024),
+        DEFINE_PROP_UINT16("max_outputs", PCIQXLDevice, max_outputs, 0),
         DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/hw/display/qxl.h b/hw/display/qxl.h
index deddd54..d045f59 100644
--- a/hw/display/qxl.h
+++ b/hw/display/qxl.h
@@ -99,6 +99,7 @@  typedef struct PCIQXLDevice {
     QXLModes           *modes;
     uint32_t           rom_size;
     MemoryRegion       rom_bar;
+    uint16_t           max_outputs;
 
     /* vram pci bar */
     uint32_t           vram_size;