[Qemu-devel] [PATCH v4 0/5] atapi: Implement 'media' subcommand for GESN

[Qemu-devel] [PATCH v4 0/5] atapi: Implement 'media' subcommand for GESN

[Amit Shah]

The GET_EVENT_STATUS_NOTIFICATION ATAPI command is listed as a
mandatory command in the spec but we don't really implement it any of
its sub-commands.

The commit message for the last commit explains why implementing just
the media subcommand is helpful and how it goes a long way in getting
guests to behave as expected.

The difference from the RFC series sent earlier is:
- Split into more patches
- Add tray open/close notification (from Markus)

There certainly is much more work to be done for the other commands
and also for state change handling (tray open / close / new media)
overall for the block layer, but this is a good first step in being
spec-compliant and at the same time making guests work.

v4:
 - gesn_event_header should point to buf
 - compile fix for patch 3/5
 - remove initialisation without effect of a variable.

v3:
 - Add gesn_event_header struct, further removing a few constants used
 - Set reserved bits to 0 for the media subcommand
 - Remove the function handling NEA, move to generic code
 - Re-do patch series to reflect above change
 - Merge vmstate patches with patch introducing new fields
 - Merge fixes for other comments by Kevin

v2:
 - Update comments
 - Use struct instead of enum for cdb packet
 - Add a new subsection to vmstate for new fields for save/restore

v1:
 - Split into more patches
 - Add tray open/close notification (from Markus)

RFC:
 - Orig. series

Amit Shah (5):
  atapi: Allow GET_EVENT_STATUS_NOTIFICATION after media change
  atapi: Move GET_EVENT_STATUS_NOTIFICATION command handling to its own
    function
  atapi: GESN: Use structs for commonly-used field types
  atapi: GESN: Standardise event response handling for future additions
  atapi: GESN: implement 'media' subcommand

 hw/ide/core.c     |  181 +++++++++++++++++++++++++++++++++++++++++++++++------
 hw/ide/internal.h |    6 ++
 2 files changed, 168 insertions(+), 19 deletions(-)

-- 
1.7.4.2

[Qemu-devel] [PATCH v4 1/5] atapi: Allow GET_EVENT_STATUS_NOTIFICATION after media change

[Amit Shah]

After a media change, the only commands allowed from the guest were
REQUEST_SENSE and INQUIRY.  The guest may also issue
GET_EVENT_STATUS_NOTIFICATION commands to get media
changed notification.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 hw/ide/core.c |   20 ++++++++++++++------
 1 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/hw/ide/core.c b/hw/ide/core.c
index c11d457..60137c6 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -1102,13 +1102,21 @@ static void ide_atapi_cmd(IDEState *s)
         printf("\n");
     }
 #endif
-    /* If there's a UNIT_ATTENTION condition pending, only
-       REQUEST_SENSE and INQUIRY commands are allowed to complete. */
+    /*
+     * If there's a UNIT_ATTENTION condition pending, only
+     * REQUEST_SENSE, INQUIRY, GET_CONFIGURATION and
+     * GET_EVENT_STATUS_NOTIFICATION commands are allowed to complete.
+     * MMC-5, section 4.1.6.1 lists only these commands being allowed
+     * to complete, with other commands getting a CHECK condition
+     * response unless a higher priority status, defined by the drive
+     * here, is pending.
+     */
     if (s->sense_key == SENSE_UNIT_ATTENTION &&
-	s->io_buffer[0] != GPCMD_REQUEST_SENSE &&
-	s->io_buffer[0] != GPCMD_INQUIRY) {
-	ide_atapi_cmd_check_status(s);
-	return;
+        s->io_buffer[0] != GPCMD_REQUEST_SENSE &&
+        s->io_buffer[0] != GPCMD_INQUIRY &&
+        s->io_buffer[0] != GPCMD_GET_EVENT_STATUS_NOTIFICATION) {
+        ide_atapi_cmd_check_status(s);
+        return;
     }
     switch(s->io_buffer[0]) {
     case GPCMD_TEST_UNIT_READY:
-- 
1.7.4.2

[Qemu-devel] [PATCH v4 2/5] atapi: Move GET_EVENT_STATUS_NOTIFICATION command handling to its own function

[Amit Shah]

This makes the code more readable.

Also, there's a block like:

if () {
  ...
} else {
  ...
}

Split that into

if () {
  ...
  return;
}
...

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 hw/ide/core.c |   37 ++++++++++++++++++++++++-------------
 1 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/hw/ide/core.c b/hw/ide/core.c
index 60137c6..5b64676 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -1084,6 +1084,29 @@ static int ide_dvd_read_structure(IDEState *s, int format,
     }
 }
 
+static void handle_get_event_status_notification(IDEState *s,
+                                                 uint8_t *buf,
+                                                 const uint8_t *packet)
+{
+    unsigned int max_len;
+
+    max_len = ube16_to_cpu(packet + 7);
+
+    if (!(packet[1] & 0x01)) { /* asynchronous mode */
+        /* Only polling is supported, asynchronous mode is not. */
+        ide_atapi_cmd_error(s, SENSE_ILLEGAL_REQUEST,
+                            ASC_INV_FIELD_IN_CMD_PACKET);
+        return;
+    }
+
+    /* polling */
+    /* We don't support any event class (yet). */
+    cpu_to_ube16(buf, 0x00); /* No event descriptor returned */
+    buf[2] = 0x80;           /* No Event Available (NEA) */
+    buf[3] = 0x00;           /* Empty supported event classes */
+    ide_atapi_cmd_reply(s, 4, max_len);
+}
+
 static void ide_atapi_cmd(IDEState *s)
 {
     const uint8_t *packet;
@@ -1530,19 +1553,7 @@ static void ide_atapi_cmd(IDEState *s)
             break;
         }
     case GPCMD_GET_EVENT_STATUS_NOTIFICATION:
-        max_len = ube16_to_cpu(packet + 7);
-
-        if (packet[1] & 0x01) { /* polling */
-            /* We don't support any event class (yet). */
-            cpu_to_ube16(buf, 0x00); /* No event descriptor returned */
-            buf[2] = 0x80;           /* No Event Available (NEA) */
-            buf[3] = 0x00;           /* Empty supported event classes */
-            ide_atapi_cmd_reply(s, 4, max_len);
-        } else { /* asynchronous mode */
-            /* Only polling is supported, asynchronous mode is not. */
-            ide_atapi_cmd_error(s, SENSE_ILLEGAL_REQUEST,
-                                ASC_INV_FIELD_IN_CMD_PACKET);
-        }
+        handle_get_event_status_notification(s, buf, packet);
         break;
     default:
         ide_atapi_cmd_error(s, SENSE_ILLEGAL_REQUEST,
-- 
1.7.4.2

[Qemu-devel] [PATCH v4 3/5] atapi: GESN: Use structs for commonly-used field types

[Amit Shah]

Instead of using magic numbers, use structs that are more descriptive of
the fields being used.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 hw/ide/core.c |   16 ++++++++++++++--
 1 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/hw/ide/core.c b/hw/ide/core.c
index 5b64676..3fa2044 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -1088,11 +1088,23 @@ static void handle_get_event_status_notification(IDEState *s,
                                                  uint8_t *buf,
                                                  const uint8_t *packet)
 {
+    struct {
+        uint8_t opcode;
+        uint8_t polled;        /* lsb bit is polled; others are reserved */
+        uint8_t reserved2[2];
+        uint8_t class;
+        uint8_t reserved3[2];
+        uint16_t len;
+        uint8_t control;
+    } __attribute__((packed)) *gesn_cdb;
+
     unsigned int max_len;
 
-    max_len = ube16_to_cpu(packet + 7);
+    gesn_cdb = (void *)packet;
+    max_len = be16_to_cpu(gesn_cdb->len);
 
-    if (!(packet[1] & 0x01)) { /* asynchronous mode */
+    /* It is fine by the MMC spec to not support async mode operations */
+    if (!(gesn_cdb->polled & 0x01)) { /* asynchronous mode */
         /* Only polling is supported, asynchronous mode is not. */
         ide_atapi_cmd_error(s, SENSE_ILLEGAL_REQUEST,
                             ASC_INV_FIELD_IN_CMD_PACKET);
-- 
1.7.4.2

[Qemu-devel] [PATCH v4 4/5] atapi: GESN: Standardise event response handling for future additions

[Amit Shah]

Handle GET_EVENT_STATUS_NOTIFICATION's No Event Available response in a
generic way so that future additions to the code to handle other
response types is easier.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 hw/ide/core.c |   25 +++++++++++++++++++------
 1 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/hw/ide/core.c b/hw/ide/core.c
index 3fa2044..dafc049 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -1098,9 +1098,17 @@ static void handle_get_event_status_notification(IDEState *s,
         uint8_t control;
     } __attribute__((packed)) *gesn_cdb;
 
-    unsigned int max_len;
+    struct {
+        uint16_t len;
+        uint8_t notification_class;
+        uint8_t supported_events;
+    } __attribute((packed)) *gesn_event_header;
+
+    unsigned int max_len, used_len;
 
     gesn_cdb = (void *)packet;
+    gesn_event_header = (void *)buf;
+
     max_len = be16_to_cpu(gesn_cdb->len);
 
     /* It is fine by the MMC spec to not support async mode operations */
@@ -1111,12 +1119,17 @@ static void handle_get_event_status_notification(IDEState *s,
         return;
     }
 
-    /* polling */
+    /* polling mode operation */
+
     /* We don't support any event class (yet). */
-    cpu_to_ube16(buf, 0x00); /* No event descriptor returned */
-    buf[2] = 0x80;           /* No Event Available (NEA) */
-    buf[3] = 0x00;           /* Empty supported event classes */
-    ide_atapi_cmd_reply(s, 4, max_len);
+    gesn_event_header->supported_events = 0;
+
+    gesn_event_header->notification_class = 0x80; /* No event available */
+    used_len = sizeof(*gesn_event_header);
+
+    gesn_event_header->len = cpu_to_be16(used_len
+                                         - sizeof(*gesn_event_header));
+    ide_atapi_cmd_reply(s, used_len, max_len);
 }
 
 static void ide_atapi_cmd(IDEState *s)
-- 
1.7.4.2

[Qemu-devel] [PATCH v4 5/5] atapi: GESN: implement 'media' subcommand

[Amit Shah]

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     |  109 ++++++++++++++++++++++++++++++++++++++++++++++++++--
 hw/ide/internal.h |    6 +++
 2 files changed, 110 insertions(+), 5 deletions(-)

diff --git a/hw/ide/core.c b/hw/ide/core.c
index dafc049..209d8e6 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -1084,6 +1084,49 @@ 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)
+{
+    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;
+
+    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;
+
+    /* These fields are reserved, just clear them. */
+    buf[6] = 0;
+    buf[7] = 0;
+
+    return 8; /* We wrote to 4 extra bytes from the header */
+}
+
 static void handle_get_event_status_notification(IDEState *s,
                                                  uint8_t *buf,
                                                  const uint8_t *packet)
@@ -1104,6 +1147,26 @@ static void handle_get_event_status_notification(IDEState *s,
         uint8_t supported_events;
     } __attribute((packed)) *gesn_event_header;
 
+    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;
 
     gesn_cdb = (void *)packet;
@@ -1121,12 +1184,25 @@ static void handle_get_event_status_notification(IDEState *s,
 
     /* polling mode operation */
 
-    /* We don't support any event class (yet). */
-    gesn_event_header->supported_events = 0;
-
-    gesn_event_header->notification_class = 0x80; /* No event available */
-    used_len = sizeof(*gesn_event_header);
+    /*
+     * These are the supported events.
+     *
+     * We currently only support requests of the 'media' type.
+     */
+    gesn_event_header->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 (gesn_cdb->class & media) {
+        gesn_event_header->notification_class |= enc_media;
+        used_len = event_status_media(s, buf, max_len);
+    } else {
+        gesn_event_header->notification_class = 0x80; /* No event available */
+        used_len = sizeof(*gesn_event_header);
+    }
     gesn_event_header->len = cpu_to_be16(used_len
                                          - sizeof(*gesn_event_header));
     ide_atapi_cmd_reply(s, used_len, max_len);
@@ -1656,6 +1732,7 @@ 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);
 }
 
@@ -2800,6 +2877,25 @@ static bool ide_drive_pio_state_needed(void *opaque)
     return (s->status & DRQ_STAT) != 0;
 }
 
+static bool ide_atapi_gesn_needed(void *opaque)
+{
+    IDEState *s = opaque;
+
+    return s->events.new_media || s->events.eject_request;
+}
+
+/* Fields for GET_EVENT_STATUS_NOTIFICATION ATAPI command */
+const VMStateDescription vmstate_ide_atapi_gesn_state = {
+    .name ="ide_drive/atapi/gesn_state",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .fields = (VMStateField []) {
+        VMSTATE_BOOL(events.new_media, IDEState),
+        VMSTATE_BOOL(events.eject_request, IDEState),
+    }
+};
+
 const VMStateDescription vmstate_ide_drive_pio_state = {
     .name = "ide_drive/pio_state",
     .version_id = 1,
@@ -2854,6 +2950,9 @@ const VMStateDescription vmstate_ide_drive = {
             .vmsd = &vmstate_ide_drive_pio_state,
             .needed = ide_drive_pio_state_needed,
         }, {
+            .vmsd = &vmstate_ide_atapi_gesn_state,
+            .needed = ide_atapi_gesn_needed,
+        }, {
             /* empty */
         }
     }
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

Re: [Qemu-devel] [PATCH v4 5/5] atapi: GESN: implement 'media' subcommand

[Kevin Wolf]

Am 12.04.2011 16:09, schrieb Amit Shah:
> 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     |  109 ++++++++++++++++++++++++++++++++++++++++++++++++++--
>  hw/ide/internal.h |    6 +++
>  2 files changed, 110 insertions(+), 5 deletions(-)
> 
> diff --git a/hw/ide/core.c b/hw/ide/core.c
> index dafc049..209d8e6 100644
> --- a/hw/ide/core.c
> +++ b/hw/ide/core.c
> @@ -1084,6 +1084,49 @@ 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)
> +{
> +    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;
> +
> +    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;
> +
> +    /* These fields are reserved, just clear them. */
> +    buf[6] = 0;
> +    buf[7] = 0;
> +
> +    return 8; /* We wrote to 4 extra bytes from the header */
> +}
> +
>  static void handle_get_event_status_notification(IDEState *s,
>                                                   uint8_t *buf,
>                                                   const uint8_t *packet)
> @@ -1104,6 +1147,26 @@ static void handle_get_event_status_notification(IDEState *s,
>          uint8_t supported_events;
>      } __attribute((packed)) *gesn_event_header;
>  
> +    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;
>  
>      gesn_cdb = (void *)packet;
> @@ -1121,12 +1184,25 @@ static void handle_get_event_status_notification(IDEState *s,
>  
>      /* polling mode operation */
>  
> -    /* We don't support any event class (yet). */
> -    gesn_event_header->supported_events = 0;
> -
> -    gesn_event_header->notification_class = 0x80; /* No event available */
> -    used_len = sizeof(*gesn_event_header);
> +    /*
> +     * These are the supported events.
> +     *
> +     * We currently only support requests of the 'media' type.
> +     */
> +    gesn_event_header->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 (gesn_cdb->class & media) {
> +        gesn_event_header->notification_class |= enc_media;

Am I missing where this field is initialized or should it be = instead
of |= ?

The rest of the series looks good, but I have seen this code by far too
often now, so maybe someone else should take over and find the remaining
bugs that I'm missing now...

Kevin

Re: [Qemu-devel] [PATCH v4 5/5] atapi: GESN: implement 'media' subcommand

[Amit Shah]

On (Tue) 12 Apr 2011 [16:54:53], Kevin Wolf wrote:
> Am 12.04.2011 16:09, schrieb Amit Shah:
> > 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     |  109 ++++++++++++++++++++++++++++++++++++++++++++++++++--
> >  hw/ide/internal.h |    6 +++
> >  2 files changed, 110 insertions(+), 5 deletions(-)
> > 
> > diff --git a/hw/ide/core.c b/hw/ide/core.c
> > index dafc049..209d8e6 100644
> > --- a/hw/ide/core.c
> > +++ b/hw/ide/core.c
> > @@ -1084,6 +1084,49 @@ 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)
> > +{
> > +    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;
> > +
> > +    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;
> > +
> > +    /* These fields are reserved, just clear them. */
> > +    buf[6] = 0;
> > +    buf[7] = 0;
> > +
> > +    return 8; /* We wrote to 4 extra bytes from the header */
> > +}
> > +
> >  static void handle_get_event_status_notification(IDEState *s,
> >                                                   uint8_t *buf,
> >                                                   const uint8_t *packet)
> > @@ -1104,6 +1147,26 @@ static void handle_get_event_status_notification(IDEState *s,
> >          uint8_t supported_events;
> >      } __attribute((packed)) *gesn_event_header;
> >  
> > +    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;
> >  
> >      gesn_cdb = (void *)packet;
> > @@ -1121,12 +1184,25 @@ static void handle_get_event_status_notification(IDEState *s,
> >  
> >      /* polling mode operation */
> >  
> > -    /* We don't support any event class (yet). */
> > -    gesn_event_header->supported_events = 0;
> > -
> > -    gesn_event_header->notification_class = 0x80; /* No event available */
> > -    used_len = sizeof(*gesn_event_header);
> > +    /*
> > +     * These are the supported events.
> > +     *
> > +     * We currently only support requests of the 'media' type.
> > +     */
> > +    gesn_event_header->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 (gesn_cdb->class & media) {
> > +        gesn_event_header->notification_class |= enc_media;
> 
> Am I missing where this field is initialized or should it be = instead
> of |= ?

I considered both: if the 'reserved' bits become available and if we
should write to them, |= makes more sense.  Currently, = will
suffice.  Strong preference?


		Amit

Re: [Qemu-devel] [PATCH v4 5/5] atapi: GESN: implement 'media' subcommand

[Jes Sorensen]

On 04/12/11 16:09, Amit Shah wrote:
> diff --git a/hw/ide/core.c b/hw/ide/core.c
> index dafc049..209d8e6 100644
> --- a/hw/ide/core.c
> +++ b/hw/ide/core.c
> @@ -1084,6 +1084,49 @@ 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)
> +{
> +    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,
> +    };

Would be nice if you used upper-case with the enums since they are
effectively just defines, to avoid confusing them with variables.

> +    uint8_t event_code, media_status;
> +
> +    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;
> +
> +    /* These fields are reserved, just clear them. */
> +    buf[6] = 0;
> +    buf[7] = 0;
> +
> +    return 8; /* We wrote to 4 extra bytes from the header */

Shouldn't you verify that you don't exceed max_len in this?

> @@ -1104,6 +1147,26 @@ static void handle_get_event_status_notification(IDEState *s,
>          uint8_t supported_events;
>      } __attribute((packed)) *gesn_event_header;
>  
> +    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,
> +    };

More lower-case enums :(

Otherwise the series looks good.

Jes

Re: [Qemu-devel] [PATCH v4 5/5] atapi: GESN: implement 'media' subcommand

[Amit Shah]

On (Tue) 12 Apr 2011 [20:33:39], Amit Shah wrote:
> On (Tue) 12 Apr 2011 [16:54:53], Kevin Wolf wrote:
> > Am 12.04.2011 16:09, schrieb Amit Shah:
> > > 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     |  109 ++++++++++++++++++++++++++++++++++++++++++++++++++--
> > >  hw/ide/internal.h |    6 +++
> > >  2 files changed, 110 insertions(+), 5 deletions(-)
> > > 
> > > diff --git a/hw/ide/core.c b/hw/ide/core.c
> > > index dafc049..209d8e6 100644
> > > --- a/hw/ide/core.c
> > > +++ b/hw/ide/core.c
> > > @@ -1084,6 +1084,49 @@ 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)
> > > +{
> > > +    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;
> > > +
> > > +    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;
> > > +
> > > +    /* These fields are reserved, just clear them. */
> > > +    buf[6] = 0;
> > > +    buf[7] = 0;
> > > +
> > > +    return 8; /* We wrote to 4 extra bytes from the header */
> > > +}
> > > +
> > >  static void handle_get_event_status_notification(IDEState *s,
> > >                                                   uint8_t *buf,
> > >                                                   const uint8_t *packet)
> > > @@ -1104,6 +1147,26 @@ static void handle_get_event_status_notification(IDEState *s,
> > >          uint8_t supported_events;
> > >      } __attribute((packed)) *gesn_event_header;
> > >  
> > > +    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;
> > >  
> > >      gesn_cdb = (void *)packet;
> > > @@ -1121,12 +1184,25 @@ static void handle_get_event_status_notification(IDEState *s,
> > >  
> > >      /* polling mode operation */
> > >  
> > > -    /* We don't support any event class (yet). */
> > > -    gesn_event_header->supported_events = 0;
> > > -
> > > -    gesn_event_header->notification_class = 0x80; /* No event available */
> > > -    used_len = sizeof(*gesn_event_header);
> > > +    /*
> > > +     * These are the supported events.
> > > +     *
> > > +     * We currently only support requests of the 'media' type.
> > > +     */
> > > +    gesn_event_header->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 (gesn_cdb->class & media) {
> > > +        gesn_event_header->notification_class |= enc_media;
> > 
> > Am I missing where this field is initialized or should it be = instead
> > of |= ?
> 
> I considered both: if the 'reserved' bits become available and if we
> should write to them, |= makes more sense.

Oh; that reminds me:  that's why I had the notification_class = 0
initialisation up there.



		Amit

Re: [Qemu-devel] [PATCH v4 5/5] atapi: GESN: implement 'media' subcommand

[Kevin Wolf]

Am 12.04.2011 17:03, schrieb Amit Shah:
> On (Tue) 12 Apr 2011 [16:54:53], Kevin Wolf wrote:
>> Am 12.04.2011 16:09, schrieb Amit Shah:
>>> 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     |  109 ++++++++++++++++++++++++++++++++++++++++++++++++++--
>>>  hw/ide/internal.h |    6 +++
>>>  2 files changed, 110 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/hw/ide/core.c b/hw/ide/core.c
>>> index dafc049..209d8e6 100644
>>> --- a/hw/ide/core.c
>>> +++ b/hw/ide/core.c
>>> @@ -1084,6 +1084,49 @@ 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)
>>> +{
>>> +    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;
>>> +
>>> +    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;
>>> +
>>> +    /* These fields are reserved, just clear them. */
>>> +    buf[6] = 0;
>>> +    buf[7] = 0;
>>> +
>>> +    return 8; /* We wrote to 4 extra bytes from the header */
>>> +}
>>> +
>>>  static void handle_get_event_status_notification(IDEState *s,
>>>                                                   uint8_t *buf,
>>>                                                   const uint8_t *packet)
>>> @@ -1104,6 +1147,26 @@ static void handle_get_event_status_notification(IDEState *s,
>>>          uint8_t supported_events;
>>>      } __attribute((packed)) *gesn_event_header;
>>>  
>>> +    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;
>>>  
>>>      gesn_cdb = (void *)packet;
>>> @@ -1121,12 +1184,25 @@ static void handle_get_event_status_notification(IDEState *s,
>>>  
>>>      /* polling mode operation */
>>>  
>>> -    /* We don't support any event class (yet). */
>>> -    gesn_event_header->supported_events = 0;
>>> -
>>> -    gesn_event_header->notification_class = 0x80; /* No event available */
>>> -    used_len = sizeof(*gesn_event_header);
>>> +    /*
>>> +     * These are the supported events.
>>> +     *
>>> +     * We currently only support requests of the 'media' type.
>>> +     */
>>> +    gesn_event_header->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 (gesn_cdb->class & media) {
>>> +        gesn_event_header->notification_class |= enc_media;
>>
>> Am I missing where this field is initialized or should it be = instead
>> of |= ?
> 
> I considered both: if the 'reserved' bits become available and if we
> should write to them, |= makes more sense.  Currently, = will
> suffice.  Strong preference?

|= is fine if the field is initialized to 0 and you add flags to it. But
this patch seems to remove the zero initialization. Maybe it's still
there somewhere, I just don't see it right now.

Kevin

Re: [Qemu-devel] [PATCH v4 5/5] atapi: GESN: implement 'media' subcommand

[Jes Sorensen]

On 04/12/11 17:13, Kevin Wolf wrote:
> Am 12.04.2011 17:03, schrieb Jes Sorensen:
>> Shouldn't you verify that you don't exceed max_len in this?
> 
> Not necessary (the buffer is always 2048 bytes), but it looks like the
> max_len parameter is unused now, so it could be removed.
> 
> Kevin

That works fine too - I just didn't like having a length and then having
it ignored completely.

Cheers,
Jes

Re: [Qemu-devel] [PATCH v4 5/5] atapi: GESN: implement 'media' subcommand

[Kevin Wolf]

Am 12.04.2011 17:03, schrieb Jes Sorensen:
> On 04/12/11 16:09, Amit Shah wrote:
>> diff --git a/hw/ide/core.c b/hw/ide/core.c
>> index dafc049..209d8e6 100644
>> --- a/hw/ide/core.c
>> +++ b/hw/ide/core.c
>> @@ -1084,6 +1084,49 @@ 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)
>> +{
>> +    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,
>> +    };
> 
> Would be nice if you used upper-case with the enums since they are
> effectively just defines, to avoid confusing them with variables.
> 
>> +    uint8_t event_code, media_status;
>> +
>> +    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;
>> +
>> +    /* These fields are reserved, just clear them. */
>> +    buf[6] = 0;
>> +    buf[7] = 0;
>> +
>> +    return 8; /* We wrote to 4 extra bytes from the header */
> 
> Shouldn't you verify that you don't exceed max_len in this?

Not necessary (the buffer is always 2048 bytes), but it looks like the
max_len parameter is unused now, so it could be removed.

Kevin

Re: [Qemu-devel] [PATCH v4 5/5] atapi: GESN: implement 'media' subcommand

[Amit Shah]

On (Tue) 12 Apr 2011 [17:11:22], Kevin Wolf wrote:
> Am 12.04.2011 17:03, schrieb Amit Shah:
> > On (Tue) 12 Apr 2011 [16:54:53], Kevin Wolf wrote:
> >> Am 12.04.2011 16:09, schrieb Amit Shah:
> >>> 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     |  109 ++++++++++++++++++++++++++++++++++++++++++++++++++--
> >>>  hw/ide/internal.h |    6 +++
> >>>  2 files changed, 110 insertions(+), 5 deletions(-)
> >>>
> >>> diff --git a/hw/ide/core.c b/hw/ide/core.c
> >>> index dafc049..209d8e6 100644
> >>> --- a/hw/ide/core.c
> >>> +++ b/hw/ide/core.c
> >>> @@ -1084,6 +1084,49 @@ 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)
> >>> +{
> >>> +    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;
> >>> +
> >>> +    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;
> >>> +
> >>> +    /* These fields are reserved, just clear them. */
> >>> +    buf[6] = 0;
> >>> +    buf[7] = 0;
> >>> +
> >>> +    return 8; /* We wrote to 4 extra bytes from the header */
> >>> +}
> >>> +
> >>>  static void handle_get_event_status_notification(IDEState *s,
> >>>                                                   uint8_t *buf,
> >>>                                                   const uint8_t *packet)
> >>> @@ -1104,6 +1147,26 @@ static void handle_get_event_status_notification(IDEState *s,
> >>>          uint8_t supported_events;
> >>>      } __attribute((packed)) *gesn_event_header;
> >>>  
> >>> +    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;
> >>>  
> >>>      gesn_cdb = (void *)packet;
> >>> @@ -1121,12 +1184,25 @@ static void handle_get_event_status_notification(IDEState *s,
> >>>  
> >>>      /* polling mode operation */
> >>>  
> >>> -    /* We don't support any event class (yet). */
> >>> -    gesn_event_header->supported_events = 0;
> >>> -
> >>> -    gesn_event_header->notification_class = 0x80; /* No event available */
> >>> -    used_len = sizeof(*gesn_event_header);
> >>> +    /*
> >>> +     * These are the supported events.
> >>> +     *
> >>> +     * We currently only support requests of the 'media' type.
> >>> +     */
> >>> +    gesn_event_header->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 (gesn_cdb->class & media) {
> >>> +        gesn_event_header->notification_class |= enc_media;
> >>
> >> Am I missing where this field is initialized or should it be = instead
> >> of |= ?
> > 
> > I considered both: if the 'reserved' bits become available and if we
> > should write to them, |= makes more sense.  Currently, = will
> > suffice.  Strong preference?
> 
> |= is fine if the field is initialized to 0 and you add flags to it. But
> this patch seems to remove the zero initialization. Maybe it's still
> there somewhere, I just don't see it right now.

Yes, I didn't think about it when you asked to remove the 0 init, but
got reminded after I saw this comment.  I'll do a v5 with the init
back in.

		Amit