[Qemu-devel] [PATCH 5/5] atapi: Implement 'media' subcommand of GET_EVENT_STATUS_NOTIFICATION command

[Amit Shah <amit.shah@redhat.com>]

Implement the 'media' sub-command of the GET_EVENT_STATUS_NOTIFICATION
command.  This helps us report tray open, tray closed, no media, media
present states to the guest.

Newer Linux kernels (2.6.38+) rely on this command to revalidate discs
after media change.

This patch also sends out tray open/closed status to the guest driver
when requested e.g. via the CDROM_DRIVE_STATUS ioctl (thanks Markus).
Without such notification, the guest and qemu's tray open/close status
was frequently out of sync, causing installers like Anaconda detecting
no disc instead of tray open, confusing them terribly.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 hw/ide/core.c     |   93 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 hw/ide/internal.h |    6 +++
 2 files changed, 97 insertions(+), 2 deletions(-)

diff --git a/hw/ide/core.c b/hw/ide/core.c
index cdc2c56..627b2cf 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -1084,6 +1084,57 @@ static int ide_dvd_read_structure(IDEState *s, int format,
     }
 }
 
+static unsigned int event_status_media(IDEState *s,
+                                       uint8_t *buf,
+                                       unsigned int max_len,
+                                       unsigned int event_class,
+                                       unsigned int supported_events)
+{
+    enum media_event_code {
+        no_change = 0,       /* Status unchanged */
+        eject_requested,     /* received a request from user to eject */
+        new_media,           /* new media inserted and ready for access */
+        media_removal,       /* only for media changers */
+        media_changed,       /* only for media changers */
+        bg_format_completed, /* MRW or DVD+RW b/g format completed */
+        bg_format_restarted, /* MRW or DVD+RW b/g format restarted */
+    };
+    enum media_status {
+        tray_open = 1,
+        media_present = 2,
+    };
+    uint8_t event_code, media_status;
+
+    if (max_len < 6) {
+        /* We're going to use 6 bytes; don't report anything if we have less */
+        return 0;
+    }
+
+    /* Event notification header */
+    cpu_to_ube16(buf, max_len);
+    buf[2] = event_class;
+    buf[3] = supported_events;
+
+    media_status = 0;
+    if (s->bs->tray_open) {
+        media_status = tray_open;
+    } else if (bdrv_is_inserted(s->bs)) {
+        media_status = media_present;
+    }
+
+    /* Event notification descriptor */
+    event_code = no_change;
+    if (media_status != tray_open && s->events.new_media) {
+        event_code = new_media;
+        s->events.new_media = false;
+    }
+
+    buf[4] = event_code;
+    buf[5] = media_status;
+
+    return 6; /* We wrote to just 2 extra bytes from the header */
+}
+
 static unsigned int event_status_nea(uint8_t *buf, unsigned int max_len)
 {
     unsigned int used_len;
@@ -1125,7 +1176,28 @@ static void handle_get_event_status_notification(IDEState *s,
         allocation_length_lsb = 8,
         control = 9,
     };
+    enum notification_class_request_type {
+        reserved1 = 1 << 0,
+        operational_change = 1 << 1,
+        power_management = 1 << 2,
+        external_request = 1 << 3,
+        media = 1 << 4,
+        multi_host = 1 << 5,
+        device_busy = 1 << 6,
+        reserved2 = 1 << 7,
+    };
+    enum event_notification_class_field {
+        enc_no_events = 0,
+        enc_operational_change,
+        enc_power_management,
+        enc_external_request,
+        enc_media,
+        enc_multiple_hosts,
+        enc_device_busy,
+        enc_reserved,
+    };
     unsigned int max_len, used_len;
+    unsigned int supported_events;
 
     max_len = ube16_to_cpu(packet + allocation_length_msb);
 
@@ -1139,8 +1211,24 @@ static void handle_get_event_status_notification(IDEState *s,
 
     /* polling mode operation */
 
-    /* We don't support any event class (yet). */
-    used_len = event_status_nea(buf, max_len);
+    /*
+     * These are the supported events.
+     *
+     * We currently only support requests of the 'media' type.
+     */
+    supported_events = media;
+
+    /*
+     * Responses to requests are to be based on request priority.  The
+     * notification_class_request_type enum above specifies the
+     * priority: upper elements are higher prio than lower ones.
+     */
+    if (packet[request] & media) {
+        used_len = event_status_media(s, buf, max_len, enc_media,
+                                      supported_events);
+    } else {
+        used_len = event_status_nea(buf, max_len);
+    }
     ide_atapi_cmd_reply(s, used_len, max_len);
 }
 
@@ -1661,6 +1749,7 @@ static void cdrom_change_cb(void *opaque, int reason)
     s->sense_key = SENSE_UNIT_ATTENTION;
     s->asc = ASC_MEDIUM_MAY_HAVE_CHANGED;
     s->cdrom_changed = 1;
+    s->events.new_media = true;
     ide_set_irq(s->bus);
 }
 
diff --git a/hw/ide/internal.h b/hw/ide/internal.h
index d533fb6..ba7e9a8 100644
--- a/hw/ide/internal.h
+++ b/hw/ide/internal.h
@@ -373,6 +373,11 @@ typedef int DMAFunc(IDEDMA *);
 typedef int DMAIntFunc(IDEDMA *, int);
 typedef void DMARestartFunc(void *, int, int);
 
+struct unreported_events {
+    bool eject_request;
+    bool new_media;
+};
+
 /* NOTE: IDEState represents in fact one drive */
 struct IDEState {
     IDEBus *bus;
@@ -408,6 +413,7 @@ struct IDEState {
     BlockDriverState *bs;
     char version[9];
     /* ATAPI specific */
+    struct unreported_events events;
     uint8_t sense_key;
     uint8_t asc;
     uint8_t cdrom_changed;
-- 
1.7.4.2