[PATCH v7 00/10] Support virtio-gpu DRM native context

[PATCH v7 00/10] Support virtio-gpu DRM native context

[Dmitry Osipenko]

This patchset adds DRM native context support to VirtIO-GPU on Qemu.

Contarary to Virgl and Venus contexts that mediates high level GFX APIs,
DRM native context [1] mediates lower level kernel driver UAPI, which
reflects in a less CPU overhead and less/simpler code needed to support it.
DRM context consists of a host and guest parts that have to be implemented
for each GPU driver. On a guest side, DRM context presents a virtual GPU as
a real/native host GPU device for GL/VK applications.

[1] https://www.youtube.com/watch?v=9sFP_yddLLQ

Today there are four DRM native context drivers existing in a wild:

  - Freedreno (Qualcomm SoC GPUs), completely upstreamed
  - AMDGPU, completely upstreamed
  - Intel (i915), merge requests are opened
  - Asahi (Apple SoC GPUs), partially merged upstream

# How to try out DRM context:

1. DRM context uses host blobs and on host requires latest 6.13 version
of Linux kernel that contains necessary KVM fixes.

2. Use latest Mesa (both guest and host) and libvirglrenderer versions.
 Use build flags documented in tha patch #10 of this series.

3. On guest, use latest Linux kernel v6.14-rc or newer.

Example Qemu cmdline that enables DRM context:

  qemu-system-x86_64 -device virtio-vga-gl,hostmem=4G,blob=on,drm_native_context=on \
      -machine q35,accel=kvm,memory-backend=mem1 \
      -object memory-backend-memfd,id=mem1,size=8G -m 8G

# Note about known performance problem in Qemu:

DRM contexts are mapping host blobs extensively and these mapping
operations work slowly in Qemu. Exact reason is unknown. Mappings work
fast on Crosvm For DRM contexts this problem is more visible than for
Venus/Virgl.

Changelog:

v7: - Added r-b from Alex Bennée to the async fencing patch.

    - Updated virtio-gpu doc patch with addressed review comments
      from Akihiko Odaki.

v6: - Fixed compilation warning using older version of virglrenderer,
      which wasn't fixed properly in v5.

    - Added t-bs from Alex Bennée.

    - Added patches to improve virgl/venus doc by adding links
      to the Mesa doc as was suggested by Akihiko Odaki.

    - Updated patch that documents guest/host requirements. Added
      links to Asahi nctx and reworked the doc structure by adding
      requirements to each context-type section instead of having
      one big blob or requirements, which was objected by Akihiko Odaki.

v5: - Added r-bs from Akihiko Odaki.

    - Added acks from Michael Tsirkin.

    - Fixed compilation warning using older version of virglrenderer that
      was reported by Alex Bennée. Noticed that I need to keep old
      virgl_write_fence() code around for the older virglrenderer in
      "Support  asynchronous fencing" patch, so added it back and verified
      that old virglrenderer works properly.

    - Added new patch from Alex Bennée that adds more virtio-gpu 
      documentation with a couple corrections and additions to it from me.

    - Rebased patches on top of latest staging tree.

v4: - Improved SDL2/dmabuf patch by reusing existing Meson X11 config 
      option, better handling EGL error and extending comment telling
      that it's safe to enable SDL2 EGL preference hint. As was suggested
      by Akihiko Odaki.

    - Replaced another QSLIST_FOREACH_SAFE with QSLIST_EMPTY+FIRST in
      the async-fencing patch for more consistency of the code. As was
      suggested by Akihiko Odaki.

    - Added missing braces around if-statement that was spotted by
      Alex Bennée.

    - Renamed 'drm=on' option of virtio-gpu-gl device to 
      'drm_native_context=on' for more clarity as was suggested by 
      Alex Bennée. Haven't added added new context-type option that 
      was also proposed by Alex, might do it with a separate patch.
      This context-type option will duplicate and depecate existing
      options, but in a longer run likely will be worthwhile adding
      it.

    - Dropped Linux headers-update patch as headers has been updated
      in the staging tree.

v3: - Improved EGL presence-check code on X11 systems for the SDL2
      hint that prefers EGL over GLX by using better ifdefs and checking
      Xlib presence at a build time to avoid build failure if lib SDL2
      and system are configured with a disabled X11 support. Also added
      clarifying comment telling that X11 hint doesn't affect Wayland
      systems. Suggested by Akihiko Odaki.

    - Corrected strerror(err) that used negative error where it should
      be positive and vice versa that was caught by Akihiko Odaki. Added
      clarifying comment for the case where we get positive error code
      from virglrenderer that differs from other virglrenderer API functions.

    - Improved QSLIST usage by dropping mutex protecting the async fence
      list and using atomic variant of QSLIST helpers instead. Switched away
      from using FOREACH helper to improve readability of the code, showing
      that we don't precess list in unoptimal way. Like was suggested by
      Akihiko Odaki.

    - Updated patchset base to Venus v18.

v2: - Updated SDL2-dmabuf patch by making use of error_report() and
      checking presense of X11+EGL in the system before making SDL2
      to prefer EGL backend over GLX, suggested by Akihiko Odaki.

    - Improved SDL2's dmabuf-presence check that wasn't done properly
      in v1, where EGL was set up only after first console was fully
      inited, and thus, SDL's display .has_dmabuf callback didn't work
      for the first console. Now dmabuf support status is pre-checked
      before console is registered.

    - Updated commit description of the patch that fixes SDL2's context
      switching logic with a more detailed explanation of the problem.
      Suggested by Akihiko Odaki.

    - Corrected rebase typo in the async-fencing patch and switched
      async-fencing to use a sigle-linked list instead of the double,
      as was suggested by Akihiko Odaki.

    - Replaced "=true" with "=on" in the DRM native context documentation
      example and made virtio_gpu_virgl_init() to fail with a error message
      if DRM context can't be initialized instead of giving a warning
      message, as was suggested by Akihiko Odaki.

    - Added patchew's dependecy tag to the cover letter as was suggested by
      Akihiko Odaki.

Alex Bennée (1):
  docs/system: virtio-gpu: Document host/guest requirements

Dmitry Osipenko (8):
  ui/sdl2: Restore original context after new context creation
  virtio-gpu: Handle virgl fence creation errors
  virtio-gpu: Support asynchronous fencing
  virtio-gpu: Support DRM native context
  ui/sdl2: Don't disable scanout when display is refreshed
  ui/gtk: Don't disable scanout when display is refreshed
  docs/system: virtio-gpu: Add link to Mesa VirGL doc
  docs/system: virtio-gpu: Update Venus link

Pierre-Eric Pelloux-Prayer (1):
  ui/sdl2: Implement dpy dmabuf functions

 docs/system/devices/virtio-gpu.rst | 108 ++++++++++++++++++-
 hw/display/virtio-gpu-gl.c         |   5 +
 hw/display/virtio-gpu-virgl.c      | 164 ++++++++++++++++++++++++++++-
 hw/display/virtio-gpu.c            |  15 +++
 include/hw/virtio/virtio-gpu.h     |  16 +++
 include/ui/sdl2.h                  |   7 ++
 meson.build                        |   6 +-
 ui/gtk-egl.c                       |   1 -
 ui/gtk-gl-area.c                   |   1 -
 ui/sdl2-gl.c                       |  68 +++++++++++-
 ui/sdl2.c                          |  42 ++++++++
 11 files changed, 422 insertions(+), 11 deletions(-)

-- 
2.47.1

[PATCH v7 01/10] ui/sdl2: Restore original context after new context creation

[Dmitry Osipenko]

SDL API changes GL context to a newly created GL context, which differs
from other GL providers that don't switch context. Change SDL backend to
restore the original GL context. This allows Qemu's virtio-gpu to support
new virglrenderer async-fencing feature for Virgl contexts, otherwise
virglrenderer's vrend creates a fence-sync context on the Qemu's
main-loop thread that erroneously stays in-use by the main-loop after
creation, not allowing vrend's fence-sync thread switch to this new
context that belongs to it.

Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 ui/sdl2-gl.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/ui/sdl2-gl.c b/ui/sdl2-gl.c
index e01d9ab0c7bf..b1fe96d6af22 100644
--- a/ui/sdl2-gl.c
+++ b/ui/sdl2-gl.c
@@ -168,6 +168,9 @@ QEMUGLContext sdl2_gl_create_context(DisplayGLCtx *dgc,
                             SDL_GL_CONTEXT_PROFILE_ES);
         ctx = SDL_GL_CreateContext(scon->real_window);
     }
+
+    SDL_GL_MakeCurrent(scon->real_window, scon->winctx);
+
     return (QEMUGLContext)ctx;
 }
 
-- 
2.47.1

[PATCH v7 02/10] ui/sdl2: Implement dpy dmabuf functions

[Dmitry Osipenko]

From: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>

If EGL is used, we can rely on dmabuf to import textures without
doing copies.

To get this working on X11, we use the existing SDL hint:
SDL_HINT_VIDEO_X11_FORCE_EGL (because dmabuf can't be used with GLX).

Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 include/ui/sdl2.h |  7 ++++++
 meson.build       |  6 ++---
 ui/sdl2-gl.c      | 64 +++++++++++++++++++++++++++++++++++++++++++++++
 ui/sdl2.c         | 42 +++++++++++++++++++++++++++++++
 4 files changed, 115 insertions(+), 4 deletions(-)

diff --git a/include/ui/sdl2.h b/include/ui/sdl2.h
index dbe6e3d9739b..9daf5ecffae7 100644
--- a/include/ui/sdl2.h
+++ b/include/ui/sdl2.h
@@ -45,6 +45,7 @@ struct sdl2_console {
     bool gui_keysym;
     SDL_GLContext winctx;
     QKbdState *kbd;
+    bool has_dmabuf;
 #ifdef CONFIG_OPENGL
     QemuGLShader *gls;
     egl_fb guest_fb;
@@ -96,5 +97,11 @@ void sdl2_gl_scanout_texture(DisplayChangeListener *dcl,
                              void *d3d_tex2d);
 void sdl2_gl_scanout_flush(DisplayChangeListener *dcl,
                            uint32_t x, uint32_t y, uint32_t w, uint32_t h);
+void sdl2_gl_scanout_dmabuf(DisplayChangeListener *dcl,
+                            QemuDmaBuf *dmabuf);
+void sdl2_gl_release_dmabuf(DisplayChangeListener *dcl,
+                            QemuDmaBuf *dmabuf);
+bool sdl2_gl_has_dmabuf(DisplayChangeListener *dcl);
+void sdl2_gl_console_init(struct sdl2_console *scon);
 
 #endif /* SDL2_H */
diff --git a/meson.build b/meson.build
index 2c9ac9cfe1e9..dce01783ccf3 100644
--- a/meson.build
+++ b/meson.build
@@ -1964,10 +1964,8 @@ if get_option('gtk') \
   endif
 endif
 
-x11 = not_found
-if gtkx11.found()
-  x11 = dependency('x11', method: 'pkg-config', required: gtkx11.found())
-endif
+x11 = dependency('x11', method: 'pkg-config', required: gtkx11.found())
+
 png = not_found
 if get_option('png').allowed() and have_system
    png = dependency('libpng', version: '>=1.6.34', required: get_option('png'),
diff --git a/ui/sdl2-gl.c b/ui/sdl2-gl.c
index b1fe96d6af22..8d53e340d40d 100644
--- a/ui/sdl2-gl.c
+++ b/ui/sdl2-gl.c
@@ -26,6 +26,8 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu/main-loop.h"
+#include "qemu/error-report.h"
 #include "ui/console.h"
 #include "ui/input.h"
 #include "ui/sdl2.h"
@@ -249,3 +251,65 @@ void sdl2_gl_scanout_flush(DisplayChangeListener *dcl,
 
     SDL_GL_SwapWindow(scon->real_window);
 }
+
+void sdl2_gl_scanout_dmabuf(DisplayChangeListener *dcl,
+                            QemuDmaBuf *dmabuf)
+{
+    struct sdl2_console *scon = container_of(dcl, struct sdl2_console, dcl);
+
+    assert(scon->opengl);
+    SDL_GL_MakeCurrent(scon->real_window, scon->winctx);
+
+    egl_dmabuf_import_texture(dmabuf);
+    if (!qemu_dmabuf_get_texture(dmabuf)) {
+        error_report("%s: failed fd=%d", __func__, qemu_dmabuf_get_fd(dmabuf));
+        return;
+    }
+
+    sdl2_gl_scanout_texture(dcl, qemu_dmabuf_get_texture(dmabuf), false,
+                            qemu_dmabuf_get_width(dmabuf),
+                            qemu_dmabuf_get_height(dmabuf),
+                            0, 0,
+                            qemu_dmabuf_get_width(dmabuf),
+                            qemu_dmabuf_get_height(dmabuf),
+                            NULL);
+
+    if (qemu_dmabuf_get_allow_fences(dmabuf)) {
+        scon->guest_fb.dmabuf = dmabuf;
+    }
+}
+
+void sdl2_gl_release_dmabuf(DisplayChangeListener *dcl,
+                            QemuDmaBuf *dmabuf)
+{
+    egl_dmabuf_release_texture(dmabuf);
+}
+
+bool sdl2_gl_has_dmabuf(DisplayChangeListener *dcl)
+{
+    struct sdl2_console *scon = container_of(dcl, struct sdl2_console, dcl);
+
+    return scon->has_dmabuf;
+}
+
+void sdl2_gl_console_init(struct sdl2_console *scon)
+{
+    bool hidden = scon->hidden;
+
+    scon->hidden = true;
+    scon->surface = qemu_create_displaysurface(1, 1);
+    sdl2_window_create(scon);
+
+    /*
+     * QEMU checks whether console supports dma-buf before switching
+     * to the console.  To break this chicken-egg problem we pre-check
+     * dma-buf availability beforehand using a dummy SDL window.
+     */
+    scon->has_dmabuf = qemu_egl_has_dmabuf();
+
+    sdl2_window_destroy(scon);
+    qemu_free_displaysurface(scon->surface);
+
+    scon->surface = NULL;
+    scon->hidden = hidden;
+}
diff --git a/ui/sdl2.c b/ui/sdl2.c
index 445eb1dd9f9a..3e262b994231 100644
--- a/ui/sdl2.c
+++ b/ui/sdl2.c
@@ -36,6 +36,10 @@
 #include "qemu/log.h"
 #include "qemu-main.h"
 
+#ifdef CONFIG_X11
+#include <X11/Xlib.h>
+#endif
+
 static int sdl2_num_outputs;
 static struct sdl2_console *sdl2_console;
 
@@ -121,6 +125,9 @@ void sdl2_window_create(struct sdl2_console *scon)
         /* The SDL renderer is only used by sdl2-2D, when OpenGL is disabled */
         scon->real_renderer = SDL_CreateRenderer(scon->real_window, -1, 0);
     }
+
+    qemu_egl_display = eglGetCurrentDisplay();
+
     sdl_update_caption(scon);
 }
 
@@ -821,6 +828,10 @@ static const DisplayChangeListenerOps dcl_gl_ops = {
     .dpy_gl_scanout_disable  = sdl2_gl_scanout_disable,
     .dpy_gl_scanout_texture  = sdl2_gl_scanout_texture,
     .dpy_gl_update           = sdl2_gl_scanout_flush,
+
+    .dpy_gl_scanout_dmabuf   = sdl2_gl_scanout_dmabuf,
+    .dpy_gl_release_dmabuf   = sdl2_gl_release_dmabuf,
+    .dpy_has_dmabuf          = sdl2_gl_has_dmabuf,
 };
 
 static bool
@@ -848,6 +859,35 @@ static void sdl2_display_early_init(DisplayOptions *o)
     }
 }
 
+static void sdl2_set_hint_x11_force_egl(void)
+{
+#if defined(SDL_HINT_VIDEO_X11_FORCE_EGL) && defined(CONFIG_OPENGL) && \
+    defined(CONFIG_X11)
+    Display *x_disp = XOpenDisplay(NULL);
+    EGLDisplay egl_display;
+
+    if (!x_disp) {
+        return;
+    }
+
+    /* Prefer EGL over GLX to get dma-buf support. */
+    egl_display = eglGetDisplay((EGLNativeDisplayType)x_disp);
+
+    if (egl_display != EGL_NO_DISPLAY) {
+        /*
+         * Setting X11_FORCE_EGL hint doesn't make SDL to prefer X11 over
+         * Wayland. SDL will use Wayland driver even if XWayland presents.
+         * It's always safe to set the hint even if X11 is not used by SDL.
+         * SDL will work regardless of the hint.
+         */
+        SDL_SetHint(SDL_HINT_VIDEO_X11_FORCE_EGL, "1");
+        eglTerminate(egl_display);
+    }
+
+    XCloseDisplay(x_disp);
+#endif
+}
+
 static void sdl2_display_init(DisplayState *ds, DisplayOptions *o)
 {
     uint8_t data = 0;
@@ -878,6 +918,7 @@ static void sdl2_display_init(DisplayState *ds, DisplayOptions *o)
     SDL_SetHint(SDL_HINT_ALLOW_ALT_TAB_WHILE_GRABBED, "0");
 #endif
     SDL_SetHint(SDL_HINT_WINDOWS_NO_CLOSE_ON_ALT_F4, "1");
+    sdl2_set_hint_x11_force_egl();
     SDL_EnableScreenSaver();
     memset(&info, 0, sizeof(info));
     SDL_VERSION(&info.version);
@@ -924,6 +965,7 @@ static void sdl2_display_init(DisplayState *ds, DisplayOptions *o)
         sdl2_console[i].kbd = qkbd_state_init(con);
         if (display_opengl) {
             qemu_console_set_display_gl_ctx(con, &sdl2_console[i].dgc);
+            sdl2_gl_console_init(&sdl2_console[i]);
         }
         register_displaychangelistener(&sdl2_console[i].dcl);
 
-- 
2.47.1

[PATCH v7 03/10] virtio-gpu: Handle virgl fence creation errors

[Dmitry Osipenko]

Print out error messages when virgl fence creation fails to aid debugging
of the fence-related bugs.

Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 hw/display/virtio-gpu-virgl.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/hw/display/virtio-gpu-virgl.c b/hw/display/virtio-gpu-virgl.c
index 145a0b387956..2eb6aaab4e84 100644
--- a/hw/display/virtio-gpu-virgl.c
+++ b/hw/display/virtio-gpu-virgl.c
@@ -872,6 +872,7 @@ void virtio_gpu_virgl_process_cmd(VirtIOGPU *g,
                                       struct virtio_gpu_ctrl_command *cmd)
 {
     bool cmd_suspended = false;
+    int ret;
 
     VIRTIO_GPU_FILL_CMD(cmd->cmd_hdr);
 
@@ -970,7 +971,17 @@ void virtio_gpu_virgl_process_cmd(VirtIOGPU *g,
     }
 
     trace_virtio_gpu_fence_ctrl(cmd->cmd_hdr.fence_id, cmd->cmd_hdr.type);
-    virgl_renderer_create_fence(cmd->cmd_hdr.fence_id, cmd->cmd_hdr.type);
+
+    /*
+     * Unlike other virglrenderer functions, this one returns a positive
+     * error code.
+     */
+    ret = virgl_renderer_create_fence(cmd->cmd_hdr.fence_id, 0);
+    if (ret) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: virgl_renderer_create_fence error: %s",
+                      __func__, strerror(ret));
+    }
 }
 
 static void virgl_write_fence(void *opaque, uint32_t fence)
-- 
2.47.1

[PATCH v7 04/10] virtio-gpu: Support asynchronous fencing

[Dmitry Osipenko]

Support asynchronous fencing feature of virglrenderer. It allows Qemu to
handle fence as soon as it's signalled instead of periodically polling
the fence status. This feature is required for enabling DRM context
support in Qemu because legacy fencing mode isn't supported for DRM
contexts in virglrenderer.

Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 hw/display/virtio-gpu-gl.c     |   3 +
 hw/display/virtio-gpu-virgl.c  | 147 +++++++++++++++++++++++++++++++--
 include/hw/virtio/virtio-gpu.h |  13 +++
 3 files changed, 154 insertions(+), 9 deletions(-)

diff --git a/hw/display/virtio-gpu-gl.c b/hw/display/virtio-gpu-gl.c
index 683fad3bf8a8..d9bb50ac1d4a 100644
--- a/hw/display/virtio-gpu-gl.c
+++ b/hw/display/virtio-gpu-gl.c
@@ -169,6 +169,9 @@ static void virtio_gpu_gl_device_unrealize(DeviceState *qdev)
     if (gl->renderer_state >= RS_INITED) {
 #if VIRGL_VERSION_MAJOR >= 1
         qemu_bh_delete(gl->cmdq_resume_bh);
+
+        virtio_gpu_virgl_reset_async_fences(g);
+        qemu_bh_delete(gl->async_fence_bh);
 #endif
         if (virtio_gpu_stats_enabled(g->parent_obj.conf)) {
             timer_free(gl->print_stats);
diff --git a/hw/display/virtio-gpu-virgl.c b/hw/display/virtio-gpu-virgl.c
index 2eb6aaab4e84..ee896eced67c 100644
--- a/hw/display/virtio-gpu-virgl.c
+++ b/hw/display/virtio-gpu-virgl.c
@@ -871,6 +871,7 @@ static void virgl_cmd_set_scanout_blob(VirtIOGPU *g,
 void virtio_gpu_virgl_process_cmd(VirtIOGPU *g,
                                       struct virtio_gpu_ctrl_command *cmd)
 {
+    VirtIOGPUGL *gl = VIRTIO_GPU_GL(g);
     bool cmd_suspended = false;
     int ret;
 
@@ -972,15 +973,34 @@ void virtio_gpu_virgl_process_cmd(VirtIOGPU *g,
 
     trace_virtio_gpu_fence_ctrl(cmd->cmd_hdr.fence_id, cmd->cmd_hdr.type);
 
-    /*
-     * Unlike other virglrenderer functions, this one returns a positive
-     * error code.
-     */
-    ret = virgl_renderer_create_fence(cmd->cmd_hdr.fence_id, 0);
-    if (ret) {
-        qemu_log_mask(LOG_GUEST_ERROR,
-                      "%s: virgl_renderer_create_fence error: %s",
-                      __func__, strerror(ret));
+    if (gl->context_fence_enabled &&
+        (cmd->cmd_hdr.flags & VIRTIO_GPU_FLAG_INFO_RING_IDX)) {
+#if VIRGL_VERSION_MAJOR >= 1
+        uint32_t flags = 0;
+
+        ret = virgl_renderer_context_create_fence(cmd->cmd_hdr.ctx_id, flags,
+                                                  cmd->cmd_hdr.ring_idx,
+                                                  cmd->cmd_hdr.fence_id);
+        if (ret) {
+            qemu_log_mask(LOG_GUEST_ERROR,
+                          "%s: virgl_renderer_context_create_fence error: %s",
+                          __func__, strerror(-ret));
+        }
+#else
+        /* gl->context_fence_enabled cannot be set with older virglrenderer */
+        g_assert_not_reached();
+#endif
+    } else {
+        /*
+         * Unlike other virglrenderer functions, this one returns a positive
+         * error code.
+         */
+        ret = virgl_renderer_create_fence(cmd->cmd_hdr.fence_id, 0);
+        if (ret) {
+            qemu_log_mask(LOG_GUEST_ERROR,
+                          "%s: virgl_renderer_create_fence error: %s",
+                          __func__, strerror(ret));
+        }
     }
 }
 
@@ -1008,6 +1028,102 @@ static void virgl_write_fence(void *opaque, uint32_t fence)
     }
 }
 
+void virtio_gpu_virgl_reset_async_fences(VirtIOGPU *g)
+{
+    struct virtio_gpu_virgl_context_fence *f;
+    VirtIOGPUGL *gl = VIRTIO_GPU_GL(g);
+
+    while (!QSLIST_EMPTY(&gl->async_fenceq)) {
+        f = QSLIST_FIRST(&gl->async_fenceq);
+
+        QSLIST_REMOVE_HEAD(&gl->async_fenceq, next);
+
+        g_free(f);
+    }
+}
+
+#if VIRGL_VERSION_MAJOR >= 1
+static void virtio_gpu_virgl_async_fence_bh(void *opaque)
+{
+    QSLIST_HEAD(, virtio_gpu_virgl_context_fence) async_fenceq;
+    struct virtio_gpu_ctrl_command *cmd, *tmp;
+    struct virtio_gpu_virgl_context_fence *f;
+    VirtIOGPU *g = opaque;
+    VirtIOGPUGL *gl = VIRTIO_GPU_GL(g);
+
+    QSLIST_MOVE_ATOMIC(&async_fenceq, &gl->async_fenceq);
+
+    while (!QSLIST_EMPTY(&async_fenceq)) {
+        f = QSLIST_FIRST(&async_fenceq);
+
+        QSLIST_REMOVE_HEAD(&async_fenceq, next);
+
+        QTAILQ_FOREACH_SAFE(cmd, &g->fenceq, next, tmp) {
+            /*
+             * the guest can end up emitting fences out of order
+             * so we should check all fenced cmds not just the first one.
+             */
+            if (cmd->cmd_hdr.fence_id > f->fence_id) {
+                continue;
+            }
+            if (cmd->cmd_hdr.flags & VIRTIO_GPU_FLAG_INFO_RING_IDX) {
+                if (cmd->cmd_hdr.ring_idx != f->ring_idx) {
+                    continue;
+                }
+                if (cmd->cmd_hdr.ctx_id != f->ctx_id) {
+                    continue;
+                }
+            } else if (f->ring_idx >= 0) {
+                /* ctx0 GL-query fences don't have ring info */
+                continue;
+            }
+            virtio_gpu_ctrl_response_nodata(g, cmd, VIRTIO_GPU_RESP_OK_NODATA);
+            QTAILQ_REMOVE(&g->fenceq, cmd, next);
+            g_free(cmd);
+        }
+
+        trace_virtio_gpu_fence_resp(f->fence_id);
+        g_free(f);
+        g->inflight--;
+        if (virtio_gpu_stats_enabled(g->parent_obj.conf)) {
+            trace_virtio_gpu_dec_inflight_fences(g->inflight);
+        }
+    }
+}
+
+static void
+virtio_gpu_virgl_push_async_fence(VirtIOGPU *g, uint32_t ctx_id,
+                                  int64_t ring_idx, uint64_t fence_id)
+{
+    struct virtio_gpu_virgl_context_fence *f;
+    VirtIOGPUGL *gl = VIRTIO_GPU_GL(g);
+
+    f = g_new(struct virtio_gpu_virgl_context_fence, 1);
+    f->ctx_id = ctx_id;
+    f->ring_idx = ring_idx;
+    f->fence_id = fence_id;
+
+    QSLIST_INSERT_HEAD_ATOMIC(&gl->async_fenceq, f, next);
+
+    qemu_bh_schedule(gl->async_fence_bh);
+}
+
+static void virgl_write_async_fence(void *opaque, uint32_t fence)
+{
+    VirtIOGPU *g = opaque;
+
+    virtio_gpu_virgl_push_async_fence(g, 0, -1, fence);
+}
+
+static void virgl_write_async_context_fence(void *opaque, uint32_t ctx_id,
+                                            uint32_t ring_idx, uint64_t fence)
+{
+    VirtIOGPU *g = opaque;
+
+    virtio_gpu_virgl_push_async_fence(g, ctx_id, ring_idx, fence);
+}
+#endif
+
 static virgl_renderer_gl_context
 virgl_create_context(void *opaque, int scanout_idx,
                      struct virgl_renderer_gl_ctx_param *params)
@@ -1095,6 +1211,8 @@ void virtio_gpu_virgl_reset_scanout(VirtIOGPU *g)
         dpy_gfx_replace_surface(g->parent_obj.scanout[i].con, NULL);
         dpy_gl_scanout_disable(g->parent_obj.scanout[i].con);
     }
+
+    virtio_gpu_virgl_reset_async_fences(g);
 }
 
 void virtio_gpu_virgl_reset(VirtIOGPU *g)
@@ -1112,6 +1230,13 @@ int virtio_gpu_virgl_init(VirtIOGPU *g)
     if (qemu_egl_display) {
         virtio_gpu_3d_cbs.version = 4;
         virtio_gpu_3d_cbs.get_egl_display = virgl_get_egl_display;
+#if VIRGL_VERSION_MAJOR >= 1
+        virtio_gpu_3d_cbs.write_fence         = virgl_write_async_fence;
+        virtio_gpu_3d_cbs.write_context_fence = virgl_write_async_context_fence;
+        flags |= VIRGL_RENDERER_ASYNC_FENCE_CB;
+        flags |= VIRGL_RENDERER_THREAD_SYNC;
+        gl->context_fence_enabled = true;
+#endif
     }
 #endif
 #ifdef VIRGL_RENDERER_D3D11_SHARE_TEXTURE
@@ -1145,6 +1270,10 @@ int virtio_gpu_virgl_init(VirtIOGPU *g)
     gl->cmdq_resume_bh = aio_bh_new(qemu_get_aio_context(),
                                     virtio_gpu_virgl_resume_cmdq_bh,
                                     g);
+
+    gl->async_fence_bh = aio_bh_new(qemu_get_aio_context(),
+                                    virtio_gpu_virgl_async_fence_bh,
+                                    g);
 #endif
 
     return 0;
diff --git a/include/hw/virtio/virtio-gpu.h b/include/hw/virtio/virtio-gpu.h
index a42957c4e2cc..bd2cccdc60d7 100644
--- a/include/hw/virtio/virtio-gpu.h
+++ b/include/hw/virtio/virtio-gpu.h
@@ -230,6 +230,13 @@ struct VirtIOGPUClass {
                              Error **errp);
 };
 
+struct virtio_gpu_virgl_context_fence {
+    uint32_t ctx_id;
+    int64_t ring_idx;
+    uint64_t fence_id;
+    QSLIST_ENTRY(virtio_gpu_virgl_context_fence) next;
+};
+
 /* VirtIOGPUGL renderer states */
 typedef enum {
     RS_START,       /* starting state */
@@ -247,6 +254,11 @@ struct VirtIOGPUGL {
     QEMUTimer *print_stats;
 
     QEMUBH *cmdq_resume_bh;
+
+    QEMUBH *async_fence_bh;
+    QSLIST_HEAD(, virtio_gpu_virgl_context_fence) async_fenceq;
+
+    bool context_fence_enabled;
 };
 
 struct VhostUserGPU {
@@ -376,5 +388,6 @@ void virtio_gpu_virgl_reset_scanout(VirtIOGPU *g);
 void virtio_gpu_virgl_reset(VirtIOGPU *g);
 int virtio_gpu_virgl_init(VirtIOGPU *g);
 GArray *virtio_gpu_virgl_get_capsets(VirtIOGPU *g);
+void virtio_gpu_virgl_reset_async_fences(VirtIOGPU *g);
 
 #endif
-- 
2.47.1

[PATCH v7 05/10] virtio-gpu: Support DRM native context

[Dmitry Osipenko]

Add support for DRM native contexts to VirtIO-GPU. DRM context is enabled
using a new virtio-gpu-gl device option "drm_native_context=on".

Unlike Virgl and Venus contexts that operate on application API level,
DRM native contexts work on a kernel UAPI level. This lower level results
in a lightweight context implementations that yield better performance.

Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 docs/system/devices/virtio-gpu.rst | 11 +++++++++++
 hw/display/virtio-gpu-gl.c         |  2 ++
 hw/display/virtio-gpu-virgl.c      | 22 ++++++++++++++++++++++
 hw/display/virtio-gpu.c            | 15 +++++++++++++++
 include/hw/virtio/virtio-gpu.h     |  3 +++
 5 files changed, 53 insertions(+)

diff --git a/docs/system/devices/virtio-gpu.rst b/docs/system/devices/virtio-gpu.rst
index b7eb0fc0e727..f20c60016376 100644
--- a/docs/system/devices/virtio-gpu.rst
+++ b/docs/system/devices/virtio-gpu.rst
@@ -82,6 +82,17 @@ of virtio-gpu host memory window. This is typically between 256M and 8G.
 
 .. _venus: https://gitlab.freedesktop.org/virgl/venus-protocol/
 
+DRM native context is supported since release of `virglrenderer`_ v1.0.0
+using `drm`_ protocol.  ``DRM`` virtio-gpu capability set ("capset") requires
+host blob support (``hostmem`` and ``blob`` fields) and should be enabled
+using ``drm_native_context`` field.  The ``hostmem`` field specifies the size
+of virtio-gpu host memory window. This is typically between 256M and 8G.
+
+.. parsed-literal::
+    -device virtio-gpu-gl,hostmem=8G,blob=on,drm_native_context=on
+
+.. _drm: https://gitlab.freedesktop.org/virgl/virglrenderer/-/tree/main/src/drm
+
 virtio-gpu rutabaga
 -------------------
 
diff --git a/hw/display/virtio-gpu-gl.c b/hw/display/virtio-gpu-gl.c
index d9bb50ac1d4a..5f374ad56396 100644
--- a/hw/display/virtio-gpu-gl.c
+++ b/hw/display/virtio-gpu-gl.c
@@ -159,6 +159,8 @@ static const Property virtio_gpu_gl_properties[] = {
                     VIRTIO_GPU_FLAG_STATS_ENABLED, false),
     DEFINE_PROP_BIT("venus", VirtIOGPU, parent_obj.conf.flags,
                     VIRTIO_GPU_FLAG_VENUS_ENABLED, false),
+    DEFINE_PROP_BIT("drm_native_context", VirtIOGPU, parent_obj.conf.flags,
+                    VIRTIO_GPU_FLAG_DRM_ENABLED, false),
 };
 
 static void virtio_gpu_gl_device_unrealize(DeviceState *qdev)
diff --git a/hw/display/virtio-gpu-virgl.c b/hw/display/virtio-gpu-virgl.c
index ee896eced67c..184ad2c588f7 100644
--- a/hw/display/virtio-gpu-virgl.c
+++ b/hw/display/virtio-gpu-virgl.c
@@ -1248,6 +1248,19 @@ int virtio_gpu_virgl_init(VirtIOGPU *g)
     if (virtio_gpu_venus_enabled(g->parent_obj.conf)) {
         flags |= VIRGL_RENDERER_VENUS | VIRGL_RENDERER_RENDER_SERVER;
     }
+    if (virtio_gpu_drm_enabled(g->parent_obj.conf)) {
+        flags |= VIRGL_RENDERER_DRM;
+
+        if (!gl->context_fence_enabled) {
+            /*
+             * Virglrenderer skips enabling DRM context support without
+             * enabled async-fence feature. VirtIO-GPU will initialize
+             * successfully, but DRM context won't be available in guest.
+             */
+            error_report("DRM native context requires EGL display");
+            return -EINVAL;
+        }
+    }
 #endif
 
     ret = virgl_renderer_init(g, flags, &virtio_gpu_3d_cbs);
@@ -1310,5 +1323,14 @@ GArray *virtio_gpu_virgl_get_capsets(VirtIOGPU *g)
         }
     }
 
+    if (virtio_gpu_drm_enabled(g->parent_obj.conf)) {
+        virgl_renderer_get_cap_set(VIRTIO_GPU_CAPSET_DRM,
+                                   &capset_max_ver,
+                                   &capset_max_size);
+        if (capset_max_size) {
+            virtio_gpu_virgl_add_capset(capset_ids, VIRTIO_GPU_CAPSET_DRM);
+        }
+    }
+
     return capset_ids;
 }
diff --git a/hw/display/virtio-gpu.c b/hw/display/virtio-gpu.c
index 11a7a8575027..165a0976480d 100644
--- a/hw/display/virtio-gpu.c
+++ b/hw/display/virtio-gpu.c
@@ -1505,6 +1505,21 @@ void virtio_gpu_device_realize(DeviceState *qdev, Error **errp)
 #endif
     }
 
+    if (virtio_gpu_drm_enabled(g->parent_obj.conf)) {
+#ifdef VIRGL_VERSION_MAJOR
+    #if VIRGL_VERSION_MAJOR >= 1
+        if (!virtio_gpu_blob_enabled(g->parent_obj.conf) ||
+            !virtio_gpu_hostmem_enabled(g->parent_obj.conf)) {
+            error_setg(errp, "drm requires enabled blob and hostmem options");
+            return;
+        }
+    #else
+        error_setg(errp, "old virglrenderer, drm unsupported");
+        return;
+    #endif
+#endif
+    }
+
     if (!virtio_gpu_base_device_realize(qdev,
                                         virtio_gpu_handle_ctrl_cb,
                                         virtio_gpu_handle_cursor_cb,
diff --git a/include/hw/virtio/virtio-gpu.h b/include/hw/virtio/virtio-gpu.h
index bd2cccdc60d7..dcdf52b192b5 100644
--- a/include/hw/virtio/virtio-gpu.h
+++ b/include/hw/virtio/virtio-gpu.h
@@ -99,6 +99,7 @@ enum virtio_gpu_base_conf_flags {
     VIRTIO_GPU_FLAG_RUTABAGA_ENABLED,
     VIRTIO_GPU_FLAG_VENUS_ENABLED,
     VIRTIO_GPU_FLAG_RESOURCE_UUID_ENABLED,
+    VIRTIO_GPU_FLAG_DRM_ENABLED,
 };
 
 #define virtio_gpu_virgl_enabled(_cfg) \
@@ -121,6 +122,8 @@ enum virtio_gpu_base_conf_flags {
     (_cfg.hostmem > 0)
 #define virtio_gpu_venus_enabled(_cfg) \
     (_cfg.flags & (1 << VIRTIO_GPU_FLAG_VENUS_ENABLED))
+#define virtio_gpu_drm_enabled(_cfg) \
+    (_cfg.flags & (1 << VIRTIO_GPU_FLAG_DRM_ENABLED))
 
 struct virtio_gpu_base_conf {
     uint32_t max_outputs;
-- 
2.47.1

[PATCH v7 06/10] ui/sdl2: Don't disable scanout when display is refreshed

[Dmitry Osipenko]

Display refreshment is invoked by a timer and it erroneously disables
the active scanout if it happens to be invoked after scanout has been
enabled. This offending scanout-disable race condition with a timer
can be easily hit when Qemu runs with a disabled vsync by using SDL or
GTK displays (with vblank_mode=0 for GTK). Refreshment of display's
content shouldn't disable the active display. Fix it by keeping the
scanout's state unchanged when display is redrawn.

Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 ui/sdl2-gl.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/ui/sdl2-gl.c b/ui/sdl2-gl.c
index 8d53e340d40d..31f8fbe03286 100644
--- a/ui/sdl2-gl.c
+++ b/ui/sdl2-gl.c
@@ -53,7 +53,6 @@ static void sdl2_gl_render_surface(struct sdl2_console *scon)
     int ww, wh;
 
     SDL_GL_MakeCurrent(scon->real_window, scon->winctx);
-    sdl2_set_scanout_mode(scon, false);
 
     SDL_GetWindowSize(scon->real_window, &ww, &wh);
     surface_gl_setup_viewport(scon->gls, scon->surface, ww, wh);
-- 
2.47.1

[PATCH v7 07/10] ui/gtk: Don't disable scanout when display is refreshed

[Dmitry Osipenko]

Display refreshment is invoked by a timer and it erroneously disables
the active scanout if it happens to be invoked after scanout has been
enabled. This offending scanout-disable race condition with a timer
can be easily hit when Qemu runs with a disabled vsync by using SDL or
GTK displays (with vblank_mode=0 for GTK). Refreshment of display's
content shouldn't disable the active display. Fix it by keeping the
scanout's state unchanged when display is redrawn.

Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 ui/gtk-egl.c     | 1 -
 ui/gtk-gl-area.c | 1 -
 2 files changed, 2 deletions(-)

diff --git a/ui/gtk-egl.c b/ui/gtk-egl.c
index f7a428c86a8d..0d1547d63ad0 100644
--- a/ui/gtk-egl.c
+++ b/ui/gtk-egl.c
@@ -179,7 +179,6 @@ void gd_egl_refresh(DisplayChangeListener *dcl)
 
     if (vc->gfx.glupdates) {
         vc->gfx.glupdates = 0;
-        gtk_egl_set_scanout_mode(vc, false);
         gd_egl_draw(vc);
     }
 }
diff --git a/ui/gtk-gl-area.c b/ui/gtk-gl-area.c
index 2c9a0db42571..53d81124f211 100644
--- a/ui/gtk-gl-area.c
+++ b/ui/gtk-gl-area.c
@@ -148,7 +148,6 @@ void gd_gl_area_refresh(DisplayChangeListener *dcl)
 
     if (vc->gfx.glupdates) {
         vc->gfx.glupdates = 0;
-        gtk_gl_area_set_scanout_mode(vc, false);
         gtk_gl_area_queue_render(GTK_GL_AREA(vc->gfx.drawing_area));
     }
 }
-- 
2.47.1

[PATCH v7 08/10] docs/system: virtio-gpu: Add link to Mesa VirGL doc

[Dmitry Osipenko]

Extend virtio-gpu documentation with a link to the Mesa VirGL
documentation.

Suggested-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 docs/system/devices/virtio-gpu.rst | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/docs/system/devices/virtio-gpu.rst b/docs/system/devices/virtio-gpu.rst
index f20c60016376..f8963c1f13cf 100644
--- a/docs/system/devices/virtio-gpu.rst
+++ b/docs/system/devices/virtio-gpu.rst
@@ -59,7 +59,7 @@ on typical modern Linux distributions.
 virtio-gpu virglrenderer
 ------------------------
 
-When using virgl accelerated graphics mode in the guest, OpenGL API calls
+When using `virgl`_ accelerated graphics mode in the guest, OpenGL API calls
 are translated into an intermediate representation (see `Gallium3D`_). The
 intermediate representation is communicated to the host and the
 `virglrenderer`_ library on the host translates the intermediate
@@ -68,6 +68,7 @@ representation back to OpenGL API calls.
 .. parsed-literal::
     -device virtio-gpu-gl
 
+.. _virgl: https://docs.mesa3d.org/drivers/virgl.html
 .. _Gallium3D: https://www.freedesktop.org/wiki/Software/gallium/
 .. _virglrenderer: https://gitlab.freedesktop.org/virgl/virglrenderer/
 
-- 
2.47.1

[PATCH v7 09/10] docs/system: virtio-gpu: Update Venus link

[Dmitry Osipenko]

Change virtio-gpu Venus link, pointing it at the Mesa Venus
documentation instead of the protocol. The Mesa doc provides more
information and also has a link to the protocol.

Suggested-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 docs/system/devices/virtio-gpu.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/system/devices/virtio-gpu.rst b/docs/system/devices/virtio-gpu.rst
index f8963c1f13cf..ea3eb052df3c 100644
--- a/docs/system/devices/virtio-gpu.rst
+++ b/docs/system/devices/virtio-gpu.rst
@@ -81,7 +81,7 @@ of virtio-gpu host memory window. This is typically between 256M and 8G.
 .. parsed-literal::
     -device virtio-gpu-gl,hostmem=8G,blob=true,venus=true
 
-.. _venus: https://gitlab.freedesktop.org/virgl/venus-protocol/
+.. _venus: https://docs.mesa3d.org/drivers/venus.html
 
 DRM native context is supported since release of `virglrenderer`_ v1.0.0
 using `drm`_ protocol.  ``DRM`` virtio-gpu capability set ("capset") requires
-- 
2.47.1

[PATCH v7 10/10] docs/system: virtio-gpu: Document host/guest requirements

[Dmitry Osipenko]

From: Alex Bennée <alex.bennee@linaro.org>

This attempts to tidy up the VirtIO GPU documentation to make the list
of requirements clearer. There are still a lot of moving parts and the
distros have some catching up to do before this is all handled
automatically.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Cc: Sergio Lopez Pascual <slp@redhat.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
[dmitry.osipenko@collabora.com: Extended and corrected doc]
---
 docs/system/devices/virtio-gpu.rst | 92 +++++++++++++++++++++++++++++-
 1 file changed, 91 insertions(+), 1 deletion(-)

diff --git a/docs/system/devices/virtio-gpu.rst b/docs/system/devices/virtio-gpu.rst
index ea3eb052df3c..56950a76aa2e 100644
--- a/docs/system/devices/virtio-gpu.rst
+++ b/docs/system/devices/virtio-gpu.rst
@@ -5,7 +5,9 @@ virtio-gpu
 ==========
 
 This document explains the setup and usage of the virtio-gpu device.
-The virtio-gpu device paravirtualizes the GPU and display controller.
+The virtio-gpu device provides a GPU and display controller
+paravirtualized using VirtIO. It supports a number of different modes
+from simple 2D displays to fully accelerated 3D graphics.
 
 Linux kernel support
 --------------------
@@ -56,6 +58,17 @@ on typical modern Linux distributions.
 .. _Mesa: https://www.mesa3d.org/
 .. _SwiftShader: https://github.com/google/swiftshader
 
+3D acceleration
+---------------
+
+3D acceleration of a virtualized GPU is still an evolving field.
+Depending on the 3D mode you are running you may need to override
+distribution supplied libraries with more recent versions or enable
+build options. There are a number of requirements the host must meet
+to be able to be able to support guests. QEMU must be able to access the
+host's GPU and for the best performance be able to reliably share GPU
+memory with the guest.
+
 virtio-gpu virglrenderer
 ------------------------
 
@@ -94,6 +107,61 @@ of virtio-gpu host memory window. This is typically between 256M and 8G.
 
 .. _drm: https://gitlab.freedesktop.org/virgl/virglrenderer/-/tree/main/src/drm
 
+.. list-table:: Linux Host Requirements
+  :header-rows: 1
+
+  * - Mode
+    - Kernel
+    - libvirglrenderer build flags
+  * - OpenGL pass-through
+    - Linux any stable version
+    - N/A
+  * - Vulkan pass-through
+    - Linux 6.13+
+    - -Dvenus=true -Drender-server=true
+  * - AMDGPU DRM native context
+    - Linux 6.13+
+    - -Ddrm-renderers=amdgpu-experimental
+  * - Freedreno DRM native context
+    - Linux 6.4+
+    - -Ddrm-renderers=msm
+  * - Intel i915 DRM native context
+    - Linux 6.13+
+    - -Ddrm-renderers=i915-experimental `mr1384`_
+  * - Asahi DRM native context
+    - Linux 6.13+
+    - -Ddrm-renderers=asahi-experimental `mr1274`_
+
+.. _mr1384: https://gitlab.freedesktop.org/virgl/virglrenderer/-/merge_requests/1384
+.. _mr1274: https://gitlab.freedesktop.org/virgl/virglrenderer/-/merge_requests/1274
+
+.. list-table:: Linux Guest Requirements
+  :header-rows: 1
+
+  * - Mode
+    - Mesa Version
+    - Mesa build flags
+  * - OpenGL pass-through
+    - 16.0.0+
+    - -Dgallium-drivers=virgl
+  * - Vulkan pass-through
+    - 24.2.0+
+    - -Dvulkan-drivers=virtio
+  * - AMDGPU DRM native context
+    - 25.0.0+
+    - -Dgallium-drivers=radeonsi -Dvulkan-drivers=amd -Damdgpu-virtio=true
+  * - Freedreno DRM native context
+    - 23.1.0+
+    - -Dgallium-drivers=freedreno -Dvulkan-drivers=freedreno
+  * - Intel i915 DRM native context
+    - `mr29870`_
+    - -Dgallium-drivers=iris -Dvulkan-drivers=intel -Dintel-virtio-experimental=true
+  * - Asahi DRM native context
+    - 24.2.0+
+    - -Dgallium-drivers=asahi -Dvulkan-drivers=asahi
+
+.. _mr29870: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29870
+
 virtio-gpu rutabaga
 -------------------
 
@@ -133,3 +201,25 @@ Surfaceless is the default if ``wsi`` is not specified.
 .. _Wayland display passthrough: https://www.youtube.com/watch?v=OZJiHMtIQ2M
 .. _gfxstream-enabled rutabaga: https://crosvm.dev/book/appendix/rutabaga_gfx.html
 .. _guest Wayland proxy: https://crosvm.dev/book/devices/wayland.html
+
+.. list-table:: Linux Host Requirements
+  :header-rows: 1
+
+  * - Mode
+    - Kernel
+    - Userspace
+  * - rutabaga-gfxstream
+    - Linux 6.13+
+    - rutabaga_gfx_ffi or vhost-user client with `gfxstream support`_
+
+.. _gfxstream support: https://github.com/rust-vmm/vhost-device/tree/main/staging/vhost-device-gpu
+
+.. list-table:: Linux Guest Requirements
+  :header-rows: 1
+
+  * - Mode
+    - Mesa Version
+    - Mesa build flags
+  * - rutabaga-gfxstream
+    - 24.3.0+
+    - -Dvulkan-drivers=gfxstream
-- 
2.47.1

Re: [PATCH v7 10/10] docs/system: virtio-gpu: Document host/guest requirements

[Akihiko Odaki]

On 2025/02/03 8:21, Dmitry Osipenko wrote:
> From: Alex Bennée <alex.bennee@linaro.org>
> 
> This attempts to tidy up the VirtIO GPU documentation to make the list
> of requirements clearer. There are still a lot of moving parts and the
> distros have some catching up to do before this is all handled
> automatically.
> 
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> Cc: Sergio Lopez Pascual <slp@redhat.com>
> Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
> [dmitry.osipenko@collabora.com: Extended and corrected doc]
> ---
>   docs/system/devices/virtio-gpu.rst | 92 +++++++++++++++++++++++++++++-
>   1 file changed, 91 insertions(+), 1 deletion(-)
> 
> diff --git a/docs/system/devices/virtio-gpu.rst b/docs/system/devices/virtio-gpu.rst
> index ea3eb052df3c..56950a76aa2e 100644
> --- a/docs/system/devices/virtio-gpu.rst
> +++ b/docs/system/devices/virtio-gpu.rst
> @@ -5,7 +5,9 @@ virtio-gpu
>   ==========
>   
>   This document explains the setup and usage of the virtio-gpu device.
> -The virtio-gpu device paravirtualizes the GPU and display controller.
> +The virtio-gpu device provides a GPU and display controller
> +paravirtualized using VirtIO. It supports a number of different modes
> +from simple 2D displays to fully accelerated 3D graphics.
>   
>   Linux kernel support
>   --------------------
> @@ -56,6 +58,17 @@ on typical modern Linux distributions.
>   .. _Mesa: https://www.mesa3d.org/
>   .. _SwiftShader: https://github.com/google/swiftshader
>   
> +3D acceleration
> +---------------
> +
> +3D acceleration of a virtualized GPU is still an evolving field.
> +Depending on the 3D mode you are running you may need to override
> +distribution supplied libraries with more recent versions or enable
> +build options. There are a number of requirements the host must meet
> +to be able to be able to support guests. QEMU must be able to access the
> +host's GPU and for the best performance be able to reliably share GPU
> +memory with the guest.
> +

What about having a bigger section for "host requirements" that includes 
the "Linux kernel support" and "3D acceleration" section?

Also it's better to note that the details of 3D acceleration 
requirements are described later as this section only contains an 
abstract description.

>   virtio-gpu virglrenderer
>   ------------------------
>   
> @@ -94,6 +107,61 @@ of virtio-gpu host memory window. This is typically between 256M and 8G.
>   
>   .. _drm: https://gitlab.freedesktop.org/virgl/virglrenderer/-/tree/main/src/drm
>   
> +.. list-table:: Linux Host Requirements
> +  :header-rows: 1
> +
> +  * - Mode

"Mode" is not a word used elsewhere. Perhaps you may call it "capability".

> +    - Kernel
> +    - libvirglrenderer build flags

Just "virglrenderer" for consistency.

> +  * - OpenGL pass-through
> +    - Linux any stable version
QEMU's support policy is different from Linux's own idea of stable 
releases. Perhaps you may refer to any Linux version compatible with QEMU.

> +    - N/A
> +  * - Vulkan pass-through
> +    - Linux 6.13+
> +    - -Dvenus=true -Drender-server=true
> +  * - AMDGPU DRM native context
> +    - Linux 6.13+
> +    - -Ddrm-renderers=amdgpu-experimental
> +  * - Freedreno DRM native context
> +    - Linux 6.4+
> +    - -Ddrm-renderers=msm
> +  * - Intel i915 DRM native context
> +    - Linux 6.13+
> +    - -Ddrm-renderers=i915-experimental `mr1384`_
> +  * - Asahi DRM native context
> +    - Linux 6.13+

Asahi does not need patches for virglrenderer but requires patches for 
the kernel too as the upstream kernel doesn't have the GPU support at all.

> +    - -Ddrm-renderers=asahi-experimental `mr1274`_
> +
> +.. _mr1384: https://gitlab.freedesktop.org/virgl/virglrenderer/-/merge_requests/1384
> +.. _mr1274: https://gitlab.freedesktop.org/virgl/virglrenderer/-/merge_requests/1274
> +
> +.. list-table:: Linux Guest Requirements
> +  :header-rows: 1
> +
> +  * - Mode
> +    - Mesa Version
> +    - Mesa build flags
> +  * - OpenGL pass-through
> +    - 16.0.0+
> +    - -Dgallium-drivers=virgl
> +  * - Vulkan pass-through
> +    - 24.2.0+
> +    - -Dvulkan-drivers=virtio
> +  * - AMDGPU DRM native context
> +    - 25.0.0+
> +    - -Dgallium-drivers=radeonsi -Dvulkan-drivers=amd -Damdgpu-virtio=true
> +  * - Freedreno DRM native context
> +    - 23.1.0+
> +    - -Dgallium-drivers=freedreno -Dvulkan-drivers=freedreno
> +  * - Intel i915 DRM native context
> +    - `mr29870`_
> +    - -Dgallium-drivers=iris -Dvulkan-drivers=intel -Dintel-virtio-experimental=true
> +  * - Asahi DRM native context
> +    - 24.2.0+
> +    - -Dgallium-drivers=asahi -Dvulkan-drivers=asahi
> +
> +.. _mr29870: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29870
> +
>   virtio-gpu rutabaga
>   -------------------
>   
> @@ -133,3 +201,25 @@ Surfaceless is the default if ``wsi`` is not specified.
>   .. _Wayland display passthrough: https://www.youtube.com/watch?v=OZJiHMtIQ2M
>   .. _gfxstream-enabled rutabaga: https://crosvm.dev/book/appendix/rutabaga_gfx.html
>   .. _guest Wayland proxy: https://crosvm.dev/book/devices/wayland.html
> +
> +.. list-table:: Linux Host Requirements
> +  :header-rows: 1
> +
> +  * - Mode
> +    - Kernel
> +    - Userspace
> +  * - rutabaga-gfxstream

This notation is not consistent with the table for virglrenderer.
Following the description of capsets will allow creating a consistent table.

> +    - Linux 6.13+
> +    - rutabaga_gfx_ffi or vhost-user client with `gfxstream support`_

rutabaga_gfx_ffi is a crate name but not mentioned in other 
documentations. This page already contains a link to
https://crosvm.dev/book/appendix/rutabaga_gfx.html so let's make it 
consistent with it.

vhost-user is irrelevant with virtio-gpu-rutabaga. Also note that QEMU 
has its own vhost-user-gpu implementation that doesn't use Rutabaga in 
contrib/vhost-user-gpu.

Regards,
Akihiko Odaki

> +
> +.. _gfxstream support: https://github.com/rust-vmm/vhost-device/tree/main/staging/vhost-device-gpu
> +
> +.. list-table:: Linux Guest Requirements
> +  :header-rows: 1
> +
> +  * - Mode
> +    - Mesa Version
> +    - Mesa build flags
> +  * - rutabaga-gfxstream
> +    - 24.3.0+
> +    - -Dvulkan-drivers=gfxstream

Re: [PATCH v7 08/10] docs/system: virtio-gpu: Add link to Mesa VirGL doc

[Akihiko Odaki]

On 2025/02/03 8:21, Dmitry Osipenko wrote:
> Extend virtio-gpu documentation with a link to the Mesa VirGL
> documentation.
> 
> Suggested-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
> ---
>   docs/system/devices/virtio-gpu.rst | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/docs/system/devices/virtio-gpu.rst b/docs/system/devices/virtio-gpu.rst
> index f20c60016376..f8963c1f13cf 100644
> --- a/docs/system/devices/virtio-gpu.rst
> +++ b/docs/system/devices/virtio-gpu.rst
> @@ -59,7 +59,7 @@ on typical modern Linux distributions.
>   virtio-gpu virglrenderer
>   ------------------------
>   
> -When using virgl accelerated graphics mode in the guest, OpenGL API calls
> +When using `virgl`_ accelerated graphics mode in the guest, OpenGL API calls
>   are translated into an intermediate representation (see `Gallium3D`_). The
>   intermediate representation is communicated to the host and the
>   `virglrenderer`_ library on the host translates the intermediate
> @@ -68,6 +68,7 @@ representation back to OpenGL API calls.
>   .. parsed-literal::
>       -device virtio-gpu-gl
>   
> +.. _virgl: https://docs.mesa3d.org/drivers/virgl.html
>   .. _Gallium3D: https://www.freedesktop.org/wiki/Software/gallium/
>   .. _virglrenderer: https://gitlab.freedesktop.org/virgl/virglrenderer/
>   

Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>

Re: [PATCH v7 09/10] docs/system: virtio-gpu: Update Venus link

[Akihiko Odaki]

On 2025/02/03 8:21, Dmitry Osipenko wrote:
> Change virtio-gpu Venus link, pointing it at the Mesa Venus
> documentation instead of the protocol. The Mesa doc provides more
> information and also has a link to the protocol.
> 
> Suggested-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>

Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>

Re: [PATCH v7 10/10] docs/system: virtio-gpu: Document host/guest requirements

[Dmitry Osipenko]

On 2/3/25 09:04, Akihiko Odaki wrote:
> On 2025/02/03 8:21, Dmitry Osipenko wrote:
>> From: Alex Bennée <alex.bennee@linaro.org>
>>
>> This attempts to tidy up the VirtIO GPU documentation to make the list
>> of requirements clearer. There are still a lot of moving parts and the
>> distros have some catching up to do before this is all handled
>> automatically.
>>
>> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>> Cc: Sergio Lopez Pascual <slp@redhat.com>
>> Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
>> [dmitry.osipenko@collabora.com: Extended and corrected doc]
>> ---
>>   docs/system/devices/virtio-gpu.rst | 92 +++++++++++++++++++++++++++++-
>>   1 file changed, 91 insertions(+), 1 deletion(-)
>>
>> diff --git a/docs/system/devices/virtio-gpu.rst b/docs/system/devices/
>> virtio-gpu.rst
>> index ea3eb052df3c..56950a76aa2e 100644
>> --- a/docs/system/devices/virtio-gpu.rst
>> +++ b/docs/system/devices/virtio-gpu.rst
>> @@ -5,7 +5,9 @@ virtio-gpu
>>   ==========
>>     This document explains the setup and usage of the virtio-gpu device.
>> -The virtio-gpu device paravirtualizes the GPU and display controller.
>> +The virtio-gpu device provides a GPU and display controller
>> +paravirtualized using VirtIO. It supports a number of different modes
>> +from simple 2D displays to fully accelerated 3D graphics.
>>     Linux kernel support
>>   --------------------
>> @@ -56,6 +58,17 @@ on typical modern Linux distributions.
>>   .. _Mesa: https://www.mesa3d.org/
>>   .. _SwiftShader: https://github.com/google/swiftshader
>>   +3D acceleration
>> +---------------
>> +
>> +3D acceleration of a virtualized GPU is still an evolving field.
>> +Depending on the 3D mode you are running you may need to override
>> +distribution supplied libraries with more recent versions or enable
>> +build options. There are a number of requirements the host must meet
>> +to be able to be able to support guests. QEMU must be able to access the
>> +host's GPU and for the best performance be able to reliably share GPU
>> +memory with the guest.
>> +
> 
> What about having a bigger section for "host requirements" that includes
> the "Linux kernel support" and "3D acceleration" section?
> 
> Also it's better to note that the details of 3D acceleration
> requirements are described later as this section only contains an
> abstract description.
> 
>>   virtio-gpu virglrenderer
>>   ------------------------
>>   @@ -94,6 +107,61 @@ of virtio-gpu host memory window. This is
>> typically between 256M and 8G.
>>     .. _drm: https://gitlab.freedesktop.org/virgl/virglrenderer/-/
>> tree/main/src/drm
>>   +.. list-table:: Linux Host Requirements
>> +  :header-rows: 1
>> +
>> +  * - Mode
> 
> "Mode" is not a word used elsewhere. Perhaps you may call it "capability".
> 
>> +    - Kernel
>> +    - libvirglrenderer build flags
> 
> Just "virglrenderer" for consistency.
> 
>> +  * - OpenGL pass-through
>> +    - Linux any stable version
> QEMU's support policy is different from Linux's own idea of stable
> releases. Perhaps you may refer to any Linux version compatible with QEMU.
> 
>> +    - N/A
>> +  * - Vulkan pass-through
>> +    - Linux 6.13+
>> +    - -Dvenus=true -Drender-server=true
>> +  * - AMDGPU DRM native context
>> +    - Linux 6.13+
>> +    - -Ddrm-renderers=amdgpu-experimental
>> +  * - Freedreno DRM native context
>> +    - Linux 6.4+
>> +    - -Ddrm-renderers=msm
>> +  * - Intel i915 DRM native context
>> +    - Linux 6.13+
>> +    - -Ddrm-renderers=i915-experimental `mr1384`_
>> +  * - Asahi DRM native context
>> +    - Linux 6.13+
> 
> Asahi does not need patches for virglrenderer but requires patches for
> the kernel too as the upstream kernel doesn't have the GPU support at all.
> 
>> +    - -Ddrm-renderers=asahi-experimental `mr1274`_
>> +
>> +.. _mr1384: https://gitlab.freedesktop.org/virgl/virglrenderer/-/
>> merge_requests/1384
>> +.. _mr1274: https://gitlab.freedesktop.org/virgl/virglrenderer/-/
>> merge_requests/1274
>> +
>> +.. list-table:: Linux Guest Requirements
>> +  :header-rows: 1
>> +
>> +  * - Mode
>> +    - Mesa Version
>> +    - Mesa build flags
>> +  * - OpenGL pass-through
>> +    - 16.0.0+
>> +    - -Dgallium-drivers=virgl
>> +  * - Vulkan pass-through
>> +    - 24.2.0+
>> +    - -Dvulkan-drivers=virtio
>> +  * - AMDGPU DRM native context
>> +    - 25.0.0+
>> +    - -Dgallium-drivers=radeonsi -Dvulkan-drivers=amd -Damdgpu-
>> virtio=true
>> +  * - Freedreno DRM native context
>> +    - 23.1.0+
>> +    - -Dgallium-drivers=freedreno -Dvulkan-drivers=freedreno
>> +  * - Intel i915 DRM native context
>> +    - `mr29870`_
>> +    - -Dgallium-drivers=iris -Dvulkan-drivers=intel -Dintel-virtio-
>> experimental=true
>> +  * - Asahi DRM native context
>> +    - 24.2.0+
>> +    - -Dgallium-drivers=asahi -Dvulkan-drivers=asahi
>> +
>> +.. _mr29870: https://gitlab.freedesktop.org/mesa/mesa/-/
>> merge_requests/29870
>> +
>>   virtio-gpu rutabaga
>>   -------------------
>>   @@ -133,3 +201,25 @@ Surfaceless is the default if ``wsi`` is not
>> specified.
>>   .. _Wayland display passthrough: https://www.youtube.com/watch?
>> v=OZJiHMtIQ2M
>>   .. _gfxstream-enabled rutabaga: https://crosvm.dev/book/appendix/
>> rutabaga_gfx.html
>>   .. _guest Wayland proxy: https://crosvm.dev/book/devices/wayland.html
>> +
>> +.. list-table:: Linux Host Requirements
>> +  :header-rows: 1
>> +
>> +  * - Mode
>> +    - Kernel
>> +    - Userspace
>> +  * - rutabaga-gfxstream
> 
> This notation is not consistent with the table for virglrenderer.
> Following the description of capsets will allow creating a consistent
> table.
> 
>> +    - Linux 6.13+
>> +    - rutabaga_gfx_ffi or vhost-user client with `gfxstream support`_
> 
> rutabaga_gfx_ffi is a crate name but not mentioned in other
> documentations. This page already contains a link to
> https://crosvm.dev/book/appendix/rutabaga_gfx.html so let's make it
> consistent with it.
> 
> vhost-user is irrelevant with virtio-gpu-rutabaga. Also note that QEMU
> has its own vhost-user-gpu implementation that doesn't use Rutabaga in
> contrib/vhost-user-gpu.

Thanks for the review! I applied all your suggestions for v8. If I
missed or got anything wrong, please comment on v8.

-- 
Best regards,
Dmitry