[Qemu-devel] [PATCH] spice: add chardev (v2)

[Alon Levy <alevy@redhat.com>]

Adding a chardev backend for spice, for usage by spice vdagent in
conjunction with a properly named virtio-serial device.

Example usage:
 qemu -device virtio-serial -chardev spicevmc,name=vdagent,id=vdagent -devic

This is equivalent to the old:
 qemu -device virtio-serial -device spicevmc,subtype=vdagent

longer to write, but generated by libvirt, and requires one less device.

v1->v2 changes:
 * removed spice-qemu-char.h, folded into spice-qemu-char.h
 * removed dead IOCTL code
 * removed comment
 * removed ifdef CONFIG_SPICE from qemu-config.c and qemu-options.hx help.
---
 Makefile.objs     |    2 +-
 qemu-char.c       |    4 +
 qemu-config.c     |    6 ++
 qemu-options.hx   |   16 ++++-
 spice-qemu-char.c |  185 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 ui/qemu-spice.h   |    3 +
 6 files changed, 214 insertions(+), 2 deletions(-)
 create mode 100644 spice-qemu-char.c

diff --git a/Makefile.objs b/Makefile.objs
index cebb945..320b2a9 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -102,7 +102,7 @@ common-obj-$(CONFIG_BRLAPI) += baum.o
 common-obj-$(CONFIG_POSIX) += migration-exec.o migration-unix.o migration-fd.o
 common-obj-$(CONFIG_WIN32) += version.o
 
-common-obj-$(CONFIG_SPICE) += ui/spice-core.o ui/spice-input.o ui/spice-display.o
+common-obj-$(CONFIG_SPICE) += ui/spice-core.o ui/spice-input.o ui/spice-display.o spice-qemu-char.o
 
 audio-obj-y = audio.o noaudio.o wavaudio.o mixeng.o
 audio-obj-$(CONFIG_SDL) += sdlaudio.o
diff --git a/qemu-char.c b/qemu-char.c
index edc9ad6..acc7130 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -97,6 +97,7 @@
 #endif
 
 #include "qemu_socket.h"
+#include "ui/qemu-spice.h"
 
 #define READ_BUF_LEN 4096
 
@@ -2495,6 +2496,9 @@ static const struct {
     || defined(__FreeBSD_kernel__)
     { .name = "parport",   .open = qemu_chr_open_pp },
 #endif
+#ifdef CONFIG_SPICE
+    { .name = "spicevmc",     .open = qemu_chr_open_spice },
+#endif
 };
 
 CharDriverState *qemu_chr_open_opts(QemuOpts *opts,
diff --git a/qemu-config.c b/qemu-config.c
index 965fa46..323d3c2 100644
--- a/qemu-config.c
+++ b/qemu-config.c
@@ -146,6 +146,12 @@ static QemuOptsList qemu_chardev_opts = {
         },{
             .name = "signal",
             .type = QEMU_OPT_BOOL,
+        },{
+            .name = "name",
+            .type = QEMU_OPT_STRING,
+        },{
+            .name = "debug",
+            .type = QEMU_OPT_NUMBER,
         },
         { /* end of list */ }
     },
diff --git a/qemu-options.hx b/qemu-options.hx
index 4d99a58..5c13f0f 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1357,6 +1357,9 @@ DEF("chardev", HAS_ARG, QEMU_OPTION_chardev,
 #if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__)
     "-chardev parport,id=id,path=path[,mux=on|off]\n"
 #endif
+#if defined(CONFIG_SPICE)
+    "-chardev spicevmc,id=id,debug=debug,name=name\n"
+#endif
     , QEMU_ARCH_ALL
 )
 
@@ -1381,7 +1384,8 @@ Backend is one of:
 @option{stdio},
 @option{braille},
 @option{tty},
-@option{parport}.
+@option{parport}
+@option{spicevmc}.
 The specific backend will determine the applicable options.
 
 All devices must have an id, which can be any string up to 127 characters long.
@@ -1557,6 +1561,16 @@ Connect to a local parallel port.
 @option{path} specifies the path to the parallel port device. @option{path} is
 required.
 
+#if defined(CONFIG_SPICE)
+@item -chardev spicevmc ,id=@var{id} ,debug=@var{debug}, name=@var{name}
+
+@option{debug} debug level for spicevmc
+
+@option{name} name of spice channel to connect to
+
+Connect to a spice virtual machine channel, such as vdiport.
+#endif
+
 @end table
 ETEXI
 
diff --git a/spice-qemu-char.c b/spice-qemu-char.c
new file mode 100644
index 0000000..0ffa674
--- /dev/null
+++ b/spice-qemu-char.c
@@ -0,0 +1,185 @@
+#include "config-host.h"
+#include "ui/qemu-spice.h"
+#include <spice.h>
+#include <spice-experimental.h>
+
+#include "osdep.h"
+
+#define dprintf(_scd, _level, _fmt, ...)                                \
+    do {                                                                \
+        static unsigned __dprintf_counter = 0;                          \
+        if (_scd->debug >= _level) {                                    \
+            fprintf(stderr, "scd: %3d: " _fmt, ++__dprintf_counter, ## __VA_ARGS__);\
+        }                                                               \
+    } while (0)
+
+#define VMC_MAX_HOST_WRITE    2048
+
+typedef struct SpiceCharDriver {
+    CharDriverState*      chr;
+    SpiceCharDeviceInstance     sin;
+    char                  *subtype;
+    bool                  active;
+    uint8_t               *buffer;
+    uint8_t               *datapos;
+    ssize_t               bufsize, datalen;
+    uint32_t              debug;
+} SpiceCharDriver;
+
+static int vmc_write(SpiceCharDeviceInstance *sin, const uint8_t *buf, int len)
+{
+    SpiceCharDriver *scd = container_of(sin, SpiceCharDriver, sin);
+    ssize_t out = 0;
+    ssize_t last_out;
+    uint8_t* p = (uint8_t*)buf;
+
+    while (len > 0) {
+        last_out = MIN(len, VMC_MAX_HOST_WRITE);
+        qemu_chr_read(scd->chr, p, last_out);
+        if (last_out > 0) {
+            out += last_out;
+            len -= last_out;
+            p += last_out;
+        } else {
+            break;
+        }
+    }
+
+    dprintf(scd, 3, "%s: %lu/%zd\n", __func__, out, len + out);
+    return out;
+}
+
+static int vmc_read(SpiceCharDeviceInstance *sin, uint8_t *buf, int len)
+{
+    SpiceCharDriver *scd = container_of(sin, SpiceCharDriver, sin);
+    int bytes = MIN(len, scd->datalen);
+
+    dprintf(scd, 2, "%s: %p %d/%d/%zd\n", __func__, scd->datapos, len, bytes, scd->datalen);
+    if (bytes > 0) {
+        memcpy(buf, scd->datapos, bytes);
+        scd->datapos += bytes;
+        scd->datalen -= bytes;
+        assert(scd->datalen >= 0);
+        if (scd->datalen == 0) {
+            scd->datapos = 0;
+        }
+    }
+    return bytes;
+}
+
+static SpiceCharDeviceInterface vmc_interface = {
+    .base.type          = SPICE_INTERFACE_CHAR_DEVICE,
+    .base.description   = "spice virtual channel char device",
+    .base.major_version = SPICE_INTERFACE_CHAR_DEVICE_MAJOR,
+    .base.minor_version = SPICE_INTERFACE_CHAR_DEVICE_MINOR,
+    .write              = vmc_write,
+    .read               = vmc_read,
+};
+
+
+static void vmc_register_interface(SpiceCharDriver *scd)
+{
+    if (scd->active) {
+        return;
+    }
+    dprintf(scd, 1, "%s\n", __func__);
+    scd->sin.base.sif = &vmc_interface.base;
+    qemu_spice_add_interface(&scd->sin.base);
+    scd->active = true;
+}
+
+static void vmc_unregister_interface(SpiceCharDriver *scd)
+{
+    if (!scd->active) {
+        return;
+    }
+    dprintf(scd, 1, "%s\n", __func__);
+    spice_server_remove_interface(&scd->sin.base);
+    scd->active = false;
+}
+
+
+static int spice_chr_write(CharDriverState *chr, const uint8_t *buf, int len)
+{
+    SpiceCharDriver *s = chr->opaque;
+
+    dprintf(s, 2, "%s: %d\n", __func__, len);
+    vmc_register_interface(s);
+    assert(s->datalen == 0);
+    if (s->bufsize < len) {
+        s->bufsize = len;
+        s->buffer = qemu_realloc(s->buffer, s->bufsize);
+    }
+    memcpy(s->buffer, buf, len);
+    s->datapos = s->buffer;
+    s->datalen = len;
+    spice_server_char_device_wakeup(&s->sin);
+    return len;
+}
+
+static void spice_chr_close(struct CharDriverState *chr)
+{
+    SpiceCharDriver *s = chr->opaque;
+
+    printf("%s\n", __func__);
+    vmc_unregister_interface(s);
+    qemu_free(s);
+}
+
+static void print_allowed_subtypes(void)
+{
+    const char** psubtype;
+    int i;
+
+    fprintf(stderr, "allowed names: ");
+    for(i=0, psubtype = spice_server_char_device_recognized_subtypes();
+        *psubtype != NULL; ++psubtype, ++i) {
+        if (i == 0) {
+            fprintf(stderr, "%s", *psubtype);
+        } else {
+            fprintf(stderr, ", %s", *psubtype);
+        }
+    }
+    fprintf(stderr, "\n");
+}
+
+CharDriverState *qemu_chr_open_spice(QemuOpts *opts)
+{
+    CharDriverState *chr;
+    SpiceCharDriver *s;
+    const char* name = qemu_opt_get(opts, "name");
+    uint32_t debug = qemu_opt_get_number(opts, "debug", 0);
+    const char** psubtype = spice_server_char_device_recognized_subtypes();
+    const char *subtype = NULL;
+
+    if (name == NULL) {
+        fprintf(stderr, "spice-qemu-char: missing name parameter\n");
+        print_allowed_subtypes();
+        return NULL;
+    }
+    for(;*psubtype != NULL; ++psubtype) {
+        if (strcmp(name, *psubtype) == 0) {
+            subtype = *psubtype;
+            break;
+        }
+    }
+    if (subtype == NULL) {
+        fprintf(stderr, "spice-qemu-char: unsupported name\n");
+        print_allowed_subtypes();
+        return NULL;
+    }
+
+    chr = qemu_mallocz(sizeof(CharDriverState));
+    s = qemu_mallocz(sizeof(SpiceCharDriver));
+    s->chr = chr;
+    s->debug = debug;
+    s->active = false;
+    s->sin.subtype = subtype;
+    chr->opaque = s;
+    chr->chr_write = spice_chr_write;
+    chr->chr_close = spice_chr_close;
+
+    qemu_chr_generic_open(chr);
+
+    return chr;
+}
diff --git a/ui/qemu-spice.h b/ui/qemu-spice.h
index 0e3ad9b..e06af17 100644
--- a/ui/qemu-spice.h
+++ b/ui/qemu-spice.h
@@ -24,6 +24,7 @@
 
 #include "qemu-option.h"
 #include "qemu-config.h"
+#include "qemu-char.h"
 
 extern int using_spice;
 
@@ -33,6 +34,8 @@ void qemu_spice_audio_init(void);
 void qemu_spice_display_init(DisplayState *ds);
 int qemu_spice_add_interface(SpiceBaseInstance *sin);
 
+CharDriverState *qemu_chr_open_spice(QemuOpts *opts);
+
 #else  /* CONFIG_SPICE */
 
 #define using_spice 0
-- 
1.7.3.3