Re: [Qemu-devel] [PATCH v3 02/26] blockdev: Introduce IF_AHCI

[Kevin Wolf <kwolf@redhat.com>]

Am 22.10.2012 12:48, schrieb Michael S. Tsirkin:
> On Fri, Oct 19, 2012 at 04:43:27PM -0400, Jason Baron wrote:
>> From: Jason Baron <jbaron@redhat.com>
>>
>> Introduce IF_AHCI so that q35 can differentiate between ide and ahci disks.
>> This allows q35 to specify its default disk type. It also allows q35 to
>> differentiate between ahci and ide disks, such that -drive if=ide does not
>> result in the creating of an ahci disk. This is important, since we don't want
>> to have the meaning of if=ide changing once q35 is introduced. Thus, its
>> important for this to be applied before we introduce q35.
>>
>> This patch also adds:
>>
>> pci_ahci_create_devs(PCIDevice *pci_dev, DriveInfo **hd_table)
>>
>> Which provides a convient way of attaching ahci drives to an
>> ahci controller.
>>
>> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
>> Signed-off-by: Jason Baron <jbaron@redhat.com>
>> ---
> 
> Kevin, could you review/ack this patch pls?
> 
>>  blockdev.c    |   13 ++++++++++++-
>>  blockdev.h    |    2 ++
>>  hw/ide.h      |    6 ++++++
>>  hw/ide/ahci.c |   18 ++++++++++++++++++
>>  hw/ide/core.c |   23 ++++++++++++++++++-----
>>  5 files changed, 56 insertions(+), 6 deletions(-)
>>
>> diff --git a/blockdev.c b/blockdev.c
>> index c9a49c8..b684348 100644
>> --- a/blockdev.c
>> +++ b/blockdev.c
>> @@ -33,6 +33,7 @@ static const char *const if_name[IF_COUNT] = {
>>      [IF_SD] = "sd",
>>      [IF_VIRTIO] = "virtio",
>>      [IF_XEN] = "xen",
>> +    [IF_AHCI] = "ahci",
>>  };
>>  
>>  static const int if_max_devs[IF_COUNT] = {
>> @@ -52,8 +53,17 @@ static const int if_max_devs[IF_COUNT] = {
>>       */
>>      [IF_IDE] = 2,
>>      [IF_SCSI] = 7,
>> +    [IF_AHCI] = 6,
>>  };

What are the implications of this if we decided to add another AHCI
controller which had a different number of ports? I suspect that a
controller with less than 6 ports breaks when you add more drives than a
single controller can handle, and one with more than 6 ports doesn't use
up all of its ports before it adds another controller.

Markus?

>> +int get_if_max_devs(BlockInterfaceType if_type)
>> +{
>> +    assert(if_type < IF_COUNT);
>> +    assert(if_type >= IF_DEFAULT);
>> +
>> +    return if_max_devs[if_type];
>> +}

if_max_devs has a specific obvious meaning within blockdev.c, but
outside it's not as obvious. So this function could use a rename.

>>  /*
>>   * We automatically delete the drive when a device using it gets
>>   * unplugged.  Questionable feature, but we can't just drop it.
>> @@ -518,7 +528,7 @@ DriveInfo *drive_init(QemuOpts *opts, int mach_if)
>>      } else {
>>          /* no id supplied -> create one */
>>          dinfo->id = g_malloc0(32);
>> -        if (type == IF_IDE || type == IF_SCSI)
>> +        if (type == IF_IDE || type == IF_SCSI || type == IF_AHCI)
>>              mediastr = (media == MEDIA_CDROM) ? "-cd" : "-hd";
>>          if (max_devs)
>>              snprintf(dinfo->id, 32, "%s%i%s%i",
>> @@ -550,6 +560,7 @@ DriveInfo *drive_init(QemuOpts *opts, int mach_if)
>>  
>>      switch(type) {
>>      case IF_IDE:
>> +    case IF_AHCI:
>>      case IF_SCSI:
>>      case IF_XEN:
>>      case IF_NONE:
>> diff --git a/blockdev.h b/blockdev.h
>> index 8b126ad..bbd1017 100644
>> --- a/blockdev.h
>> +++ b/blockdev.h
>> @@ -21,6 +21,7 @@ typedef enum {
>>      IF_DEFAULT = -1,            /* for use with drive_add() only */
>>      IF_NONE,
>>      IF_IDE, IF_SCSI, IF_FLOPPY, IF_PFLASH, IF_MTD, IF_SD, IF_VIRTIO, IF_XEN,
>> +    IF_AHCI,
>>      IF_COUNT
>>  } BlockInterfaceType;
>>  
>> @@ -56,6 +57,7 @@ static inline int get_mach_if(int mach_if)
>>      return mach_if;
>>  }
>>  
>> +int get_if_max_devs(BlockInterfaceType if_type);
>>  DriveInfo *drive_get(BlockInterfaceType type, int bus, int unit);
>>  DriveInfo *drive_get_by_index(BlockInterfaceType type, int index);
>>  int drive_get_max_bus(BlockInterfaceType type);
>> diff --git a/hw/ide.h b/hw/ide.h
>> index 2db4079..0b7e000 100644
>> --- a/hw/ide.h
>> +++ b/hw/ide.h
>> @@ -4,6 +4,7 @@
>>  #include "isa.h"
>>  #include "pci.h"
>>  #include "memory.h"
>> +#include "blockdev.h"
>>  
>>  #define MAX_IDE_DEVS	2
>>  
>> @@ -34,6 +35,11 @@ int ide_get_geometry(BusState *bus, int unit,
>>  int ide_get_bios_chs_trans(BusState *bus, int unit);
>>  
>>  /* ide/core.c */
>> +void ata_drive_get(DriveInfo **hd, int max_bus, BlockInterfaceType type);
>>  void ide_drive_get(DriveInfo **hd, int max_bus);
>> +void ahci_drive_get(DriveInfo **hd, int max_bus);
>> +
>> +/* ide/ahci.c */
>> +void pci_ahci_create_devs(PCIDevice *pci_dev, DriveInfo **hd_table);
>>  
>>  #endif /* HW_IDE_H */
>> diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
>> index 68671bc..824b86f 100644
>> --- a/hw/ide/ahci.c
>> +++ b/hw/ide/ahci.c
>> @@ -26,6 +26,7 @@
>>  #include <hw/pc.h>
>>  #include <hw/pci.h>
>>  #include <hw/sysbus.h>
>> +#include <blockdev.h>
>>  
>>  #include "monitor.h"
>>  #include "dma.h"
>> @@ -1260,3 +1261,20 @@ static void sysbus_ahci_register_types(void)
>>  }
>>  
>>  type_init(sysbus_ahci_register_types)
>> +
>> +void pci_ahci_create_devs(PCIDevice *pci_dev, DriveInfo **hd_table)
>> +{
>> +    struct AHCIPCIState *dev = DO_UPCAST(struct AHCIPCIState, card, pci_dev);
>> +    int i;
>> +    DriveInfo *drive;
>> +
>> +    for (i = 0; i < dev->ahci.ports; i++) {
>> +        if (hd_table[i] == NULL) {
>> +            continue;
>> +        }
>> +        drive = hd_table[i];
>> +        assert(drive->type == IF_AHCI);
>> +        ide_create_drive(&dev->ahci.dev[i].port, 0,
>> +                         hd_table[i]);
>> +    }
>> +}
>> diff --git a/hw/ide/core.c b/hw/ide/core.c
>> index d683a8c..044da3c 100644
>> --- a/hw/ide/core.c
>> +++ b/hw/ide/core.c
>> @@ -2341,16 +2341,29 @@ const VMStateDescription vmstate_ide_bus = {
>>      }
>>  };
>>  
>> -void ide_drive_get(DriveInfo **hd, int max_bus)
>> +void ata_drive_get(DriveInfo **hd, int max_bus, BlockInterfaceType type)

Could be static?

>>  {
>>      int i;
>> +    int max_devs;
>> +
>> +    assert((type == IF_IDE) || type == IF_AHCI);

Interesting use of brackets.

>>  
>> -    if (drive_get_max_bus(IF_IDE) >= max_bus) {
>> +    if (drive_get_max_bus(type) >= max_bus) {
>>          fprintf(stderr, "qemu: too many IDE bus: %d\n", max_bus);

"Too many %s buses", type == IF_IDE ? "IDE" : "AHCI"

>>          exit(1);
>>      }
>> -
>> -    for(i = 0; i < max_bus * MAX_IDE_DEVS; i++) {
>> -        hd[i] = drive_get(IF_IDE, i / MAX_IDE_DEVS, i % MAX_IDE_DEVS);
>> +    max_devs = get_if_max_devs(type);
>> +    for (i = 0; i < max_bus * max_devs; i++) {
>> +        hd[i] = drive_get(type, i / max_devs, i % max_devs);
>>      }
>>  }
>> +
>> +void ide_drive_get(DriveInfo **hd, int max_bus)
>> +{
>> +    ata_drive_get(hd, max_bus, IF_IDE);
>> +}
>> +
>> +void ahci_drive_get(DriveInfo **hd, int max_bus)
>> +{
>> +    ata_drive_get(hd, max_bus, IF_AHCI);
>> +}

Kevin