John Snow <js...@redhat.com> writes:
> Instead of duplicating the logic for the if_ide
> (bus,unit) mappings, rely on the blockdev layer
> for managing those mappings for us, and use the
> drive_get_by_index call instead.
>
> This allows ide_drive_get to work for AHCI HBAs
> as well, and can be used in the Q35 initialization.
>
> Lastly, change the nature of the argument to
> ide_drive_get so that represents the number of
> total drives we can support, and not the total
> number of buses. This will prevent array overflows
> if the units-per-default-bus property ever needs
> to be adjusted for compatibility reasons.
>
> Signed-off-by: John Snow <js...@redhat.com>
> ---
> blockdev.c | 9 +++++++++
> hw/alpha/dp264.c | 2 +-
> hw/i386/pc_piix.c | 2 +-
> hw/ide/core.c | 21 +++++++++++++++------
> hw/mips/mips_fulong2e.c | 2 +-
> hw/mips/mips_malta.c | 2 +-
> hw/mips/mips_r4k.c | 2 +-
> hw/ppc/mac_newworld.c | 2 +-
> hw/ppc/mac_oldworld.c | 2 +-
> hw/ppc/prep.c | 2 +-
> hw/sparc64/sun4u.c | 2 +-
> include/sysemu/blockdev.h | 1 +
> 12 files changed, 34 insertions(+), 15 deletions(-)
>
> diff --git a/blockdev.c b/blockdev.c
> index 9b05f1b..ffaad39 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -135,6 +135,15 @@ void blockdev_auto_del(BlockDriverState *bs)
> }
> }
>
> +int drive_get_max_devs(BlockInterfaceType type)
> +{
> + if (type >= IF_IDE && type < IF_COUNT) {
> + return if_max_devs[type];
> + }
> +
> + return 0;
> +}
> +
drive_get_max_bus() returns -1 for a type without drives. Includes
invalid types. When it returns a non-negative number, a drive on that
bus exists.
Your drive_get_max_devs() has a similar name, but different semantics:
it returns a positive number when the implied HBA supports multiple
buses, else zero. The "else" includes invalid types. When it returns a
positive number, then the HBA can take that many units per bus.
No big deal, but functions comments would be nice.
Should invalid type be treated as a programming error instead?
> static int drive_index_to_bus_id(BlockInterfaceType type, int index)
> {
> int max_devs = if_max_devs[type];
> diff --git a/hw/alpha/dp264.c b/hw/alpha/dp264.c
> index b178a03..ab61bb6 100644
> --- a/hw/alpha/dp264.c
> +++ b/hw/alpha/dp264.c
> @@ -97,7 +97,7 @@ static void clipper_init(MachineState *machine)
> /* IDE disk setup. */
> {
> DriveInfo *hd[MAX_IDE_BUS * MAX_IDE_DEVS];
> - ide_drive_get(hd, MAX_IDE_BUS);
> + ide_drive_get(hd, MAX_IDE_BUS * MAX_IDE_DEVS);
More obviously correct would be
ide_drive_get(hd, ARRAY_SIZE(hd));
Less so here, because the declaration is right next to the use, more so
elsewhere, where it isn't.
>
> pci_cmd646_ide_init(pci_bus, hd, 0);
> }
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index 103d756..2760c81 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -239,7 +239,7 @@ static void pc_init1(MachineState *machine,
>
> pc_nic_init(isa_bus, pci_bus);
>
> - ide_drive_get(hd, MAX_IDE_BUS);
> + ide_drive_get(hd, MAX_IDE_BUS * MAX_IDE_DEVS);
> if (pci_enabled) {
> PCIDevice *dev;
> if (xen_enabled()) {
> diff --git a/hw/ide/core.c b/hw/ide/core.c
> index 190700a..e7c1050 100644
> --- a/hw/ide/core.c
> +++ b/hw/ide/core.c
> @@ -2558,16 +2558,25 @@ const VMStateDescription vmstate_ide_bus = {
> }
> };
>
> -void ide_drive_get(DriveInfo **hd, int max_bus)
> +void ide_drive_get(DriveInfo **hd, int n)
> {
> int i;
> + int highest_bus = drive_get_max_bus(IF_IDE) + 1;
Actually, this is the "highest bus" + 1 :)
> + int n_buses = n / drive_get_max_devs(IF_IDE);
What if drive_get_max_devs(IF_IDE) returns 0?
You could side-step the question by using drive_index_to_bus_id(n).
>
> - if (drive_get_max_bus(IF_IDE) >= max_bus) {
> - fprintf(stderr, "qemu: too many IDE bus: %d\n", max_bus);
> - exit(1);
Before: fatal.
> + /* Note: The number of actual buses available is not known.
> + * We compute this based on the size of the DriveInfo* array, n.
> + * If it is less than (drive_get_max_devs(IF_IDE) * num_real_buses),
> + * We will stop looking for drives prematurely instead of overfilling
> + * the array. */
> +
You might want to consider winged comments:
/*
* Note: The number of actual buses available is not known.
* We compute this based on the size of the DriveInfo* array, n.
* If it is less than (drive_get_max_devs(IF_IDE) * num_real_buses),
* We will stop looking for drives prematurely instead of overfilling
* the array.
*/
> + if (highest_bus > n_buses) {
> + error_report("Warning: Too many IDE buses defined (%d > %d)",
> + highest_bus, n_buses);
After: warning.
Why?
> }
>
> - for(i = 0; i < max_bus * MAX_IDE_DEVS; i++) {
> - hd[i] = drive_get(IF_IDE, i / MAX_IDE_DEVS, i % MAX_IDE_DEVS);
> + for (i = 0; i < n; i++) {
> + hd[i] = drive_get_by_index(IF_IDE, i);
> }
> +
Stray blank line.
> }
Function is much nicer now, thanks!
[...]
