hw/qxl: support client monitor configuration via device

Until now we used only the agent to change the monitor count and each
monitor resolution. This patch introduces the qemu part of using the
device as the mediator instead of the agent via virtio-serial.

Spice (>=0.11.5) calls the new QXLInterface::client_monitors_config,
which returns wether the interrupt is enabled, and if so and given a non
NULL monitors config will
generate an interrupt QXL_INTERRUPT_CLIENT_MONITORS_CONFIG with crc
checksum for the guest to verify a second call hasn't interfered.

The maximal number of monitors is limited on the QXLRom to 64.

Signed-off-by: Alon Levy <alevy@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 79 insertions, 0 deletions

diff --git a/hw/qxl.c b/hw/qxl.c
index 5709e0d957..c464408421 100644
--- a/hw/qxl.c
+++ b/hw/qxl.c
@@ -18,6 +18,8 @@
  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <zlib.h>
+
 #include "qemu-common.h"
 #include "qemu-timer.h"
 #include "qemu-queue.h"
@@ -971,6 +973,79 @@ static void interface_set_client_capabilities(QXLInstance *sin,
 
 #endif
 
+#if defined(CONFIG_QXL_CLIENT_MONITORS_CONFIG) \
+    && SPICE_SERVER_VERSION >= 0x000b05
+
+static uint32_t qxl_crc32(const uint8_t *p, unsigned len)
+{
+    /*
+     * zlib xors the seed with 0xffffffff, and xors the result
+     * again with 0xffffffff; Both are not done with linux's crc32,
+     * which we want to be compatible with, so undo that.
+     */
+    return crc32(0xffffffff, p, len) ^ 0xffffffff;
+}
+
+/* called from main context only */
+static int interface_client_monitors_config(QXLInstance *sin,
+                                        VDAgentMonitorsConfig *monitors_config)
+{
+    PCIQXLDevice *qxl = container_of(sin, PCIQXLDevice, ssd.qxl);
+    QXLRom *rom = memory_region_get_ram_ptr(&qxl->rom_bar);
+    int i;
+
+    /*
+     * Older windows drivers set int_mask to 0 when their ISR is called,
+     * then later set it to ~0. So it doesn't relate to the actual interrupts
+     * handled. However, they are old, so clearly they don't support this
+     * interrupt
+     */
+    if (qxl->ram->int_mask == 0 || qxl->ram->int_mask == ~0 ||
+        !(qxl->ram->int_mask & QXL_INTERRUPT_CLIENT_MONITORS_CONFIG)) {
+        trace_qxl_client_monitors_config_unsupported_by_guest(qxl->id,
+                                                            qxl->ram->int_mask,
+                                                            monitors_config);
+        return 0;
+    }
+    if (!monitors_config) {
+        return 1;
+    }
+    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)) {
+        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);
+    }
+    for (i = 0 ; i < rom->client_monitors_config.count ; ++i) {
+        VDAgentMonConfig *monitor = &monitors_config->monitors[i];
+        QXLURect *rect = &rom->client_monitors_config.heads[i];
+        /* monitor->depth ignored */
+        rect->left = monitor->x;
+        rect->top = monitor->y;
+        rect->right = monitor->x + monitor->width;
+        rect->bottom = monitor->y + monitor->height;
+    }
+    rom->client_monitors_config_crc = qxl_crc32(
+            (const uint8_t *)&rom->client_monitors_config,
+            sizeof(rom->client_monitors_config));
+    trace_qxl_client_monitors_config_crc(qxl->id,
+            sizeof(rom->client_monitors_config),
+            rom->client_monitors_config_crc);
+
+    trace_qxl_interrupt_client_monitors_config(qxl->id,
+                        rom->client_monitors_config.count,
+                        rom->client_monitors_config.heads);
+    qxl_send_events(qxl, QXL_INTERRUPT_CLIENT_MONITORS_CONFIG);
+    return 1;
+}
+#endif
+
 static const QXLInterface qxl_interface = {
     .base.type               = SPICE_INTERFACE_QXL,
     .base.description        = "qxl gpu",
@@ -995,6 +1070,10 @@ static const QXLInterface qxl_interface = {
 #if SPICE_SERVER_VERSION >= 0x000b04
     .set_client_capabilities = interface_set_client_capabilities,
 #endif
+#if SPICE_SERVER_VERSION >= 0x000b05 && \
+    defined(CONFIG_QXL_CLIENT_MONITORS_CONFIG)
+    .client_monitors_config = interface_client_monitors_config,
+#endif
 };
 
 static void qxl_enter_vga_mode(PCIQXLDevice *d)