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Re: [Qemu-devel] [PATCH v3 02/26] blockdev: Introduce IF_AHCI
From: |
Jason Baron |
Subject: |
Re: [Qemu-devel] [PATCH v3 02/26] blockdev: Introduce IF_AHCI |
Date: |
Wed, 24 Oct 2012 15:36:25 -0400 |
User-agent: |
Mutt/1.5.20 (2009-12-10) |
On Wed, Oct 24, 2012 at 05:50:25PM +0200, Markus Armbruster wrote:
> Jason Baron <address@hidden> writes:
>
> > On Mon, Oct 22, 2012 at 01:40:21PM +0200, Kevin Wolf wrote:
> >> >> From: Jason Baron <address@hidden>
> >> >>
> >> >> 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 isn't the real argument for IF_AHCI. The real argument is that the
> (bus, unit) namespace for if=ide makes no sense for AHCI.
>
> A board can have any number of IDE controllers. Each IDE controller
> provides one or two buses, and each bus takes up to two units.
> Together, we get a a board-specific number of buses, where each bus
> takes up to two units.
>
> A board can have any number of AHCI controllers. Each AHCI controller
> provides a device-specific number of ports. Together, we get a
> board-specific number of buses, where each bus can takes a bus-specific
> number of units.
>
> Plain q35 doesn't really need to differentiate between IDE and AHCI; it
> has only AHCI. What it needs is a "one bus with six units" namespace.
>
> We could fix this by relaxing if=ide's rigid "two units per bus" for new
> machine types.
>
> You fix it by introducing if=ahci. Probably simpler. But what's the
> plan for the next generation of controller? Yet another interface type?
Next generation might require a new interface type. But taking you're
suggestions, if=ahci is now machine dependent, so it shouldn't be so bad
(see incremental patch at end).
>
> Note that SCSI suffers from similar rigidity: seven units per bus.
> That's fine for SCSI-1, but not for some of the other variants.
>
> "Differentiate" comes into play when a board sports both AHCI and IDE
> controllers. Which q35 doesn't, does it?
Yes, there is no ide controller by default. That said i've used the
piix-ide controller to install windows xp, for example, on q35.
>
> Then, the new if=ahci lets users select the kind of controller more
> easily than bus numbers would.
>
> Drawback: existing command lines upgrade from pc to plain q35 gracefully
> only if they don't specify if=ide explicitly. Upgrading to some q35
> variant with IDE controller on board is even worse: it works, but
> performance sucks. Some regard this as a feature.
>
well if=ide could give a warning on q35, suggesting using if=ahci, if
we're not going to create an ide controller for if=ide (which I wasn't
intending).
> >> >> 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 <address@hidden>
> >> >> Signed-off-by: Jason Baron <address@hidden>
> >> >> ---
> >> >
> >> > 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] = {
> /*
> * Do not change these numbers! They govern how drive option
> * index maps to unit and bus. That mapping is ABI.
> *
> * All controllers used to imlement if=T drives need to support
> * if_max_devs[T] units, for any T with if_max_devs[T] != 0.
> * Otherwise, some index values map to "impossible" bus, unit
> * values.
> *
> * For instance, if you change [IF_SCSI] to 255, -drive
> * if=scsi,index=12 no longer means bus=1,unit=5, but
> * bus=0,unit=12. With an lsi53c895a controller (7 units max),
> * the drive can't be set up. Regression.
> >> >> */
> >> >> [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?
> >>
> >
> > My plan was to make this field, machine dependent if/when we wanted a
> > different
> > size. I don't think it breaks anything to make this change at a later
> > point. But please correct me, if I am wrong.
>
> I'm afraid you are. See the comment immediately above, and commit
> 27d6bf40.
>
> As far as I can see, the least bad solution is leaving
> if_max_devs[IF_AHCI] zero. Makes index=N an alias for unit=N,bus=0, and
> leaves rejecting invalid (bus,unit) to the board.
>
Ok. I've done that. And it makes if=ahci machine dependent.
> >> >> +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.
> >
> > ok.
>
> No, get rid of it. if_max_devs[]'s purpose is mapping between index and
> (bus, unit), no more. See below.
>
done.
> >> >> /*
> >> >> * 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);
>
> Shouldn't this go next to pci_ide_create_devs()'s declaration?
> Currently in hw/ide/pci.h.
>
done.
> >> >>
> >> >> #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]);
> >> >> + }
> >> >> +}
>
> Shouldn't this go next to pci_ide_create_devs()'s definition? Currently
> in hw/ide/pci.c.
>
> Consider adding a parameter for the number of elements in hd_table[],
> for robustness. As is, the caller has to ensure hd_table[] has at least
> dev->ahci.ports elements, which is not obvious from the function
> signature.
>
> >> >> 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?
> >>
> >
> > Yes.
> >
> >> >> {
> >> >> int i;
> >> >> + int max_devs;
> >> >> +
> >> >> + assert((type == IF_IDE) || type == IF_AHCI);
> >>
> >> Interesting use of brackets.
> >
> > oops.
> >
> >>
> >> >>
> >> >> - 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"
> >
> > ok.
> >
> >>
> >> >> 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);
> >> >> +}
>
> For IDE, we always have two devices per bus. The boards number of buses
> varies in theory, and is always two in practice. Thus we have "#define
> MAX_IDE_DEVS 2" in ide.h, and "#define MAX_IDE_BUS 2" in all the
> <board>.c. The latter is passed to ide_drive_get() as parameter.
> Getting the well-known MAX_IDE_DEVS from get_if_max_devs() buys us
> nothing.
>
> For AHCI, I figure we have a device-specific number of ports per device,
> and a board-specific number of devices (typically one). If there are
> multiple devices, they don't necessarily sport the same number of ports.
> Thus, a nested loop does not work.
>
> Suggest
>
> void ahci_drive_get(DriveInfo **hd, int bus, int max_ports)
>
> which the board can call once for each device, with the device's true
> number of ports as argument. Look ma, no get_if_max_devs()!
Agreed.
So here is an incremental patch. If its too hard to read I'll send a
full diff - I'd like to include something like this in my next q35
series. thoughts?
Thanks,
-Jason
diff --git a/blockdev.c b/blockdev.c
index b684348..e17016e 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -53,17 +53,9 @@ static const int if_max_devs[IF_COUNT] = {
*/
[IF_IDE] = 2,
[IF_SCSI] = 7,
- [IF_AHCI] = 6,
+ [IF_AHCI] = 0,
};
-int get_if_max_devs(BlockInterfaceType if_type)
-{
- assert(if_type < IF_COUNT);
- assert(if_type >= IF_DEFAULT);
-
- return if_max_devs[if_type];
-}
-
/*
* We automatically delete the drive when a device using it gets
* unplugged. Questionable feature, but we can't just drop it.
@@ -168,6 +160,20 @@ int drive_get_max_bus(BlockInterfaceType type)
return max_bus;
}
+int drive_get_max_unit(BlockInterfaceType type)
+{
+ int max_unit;
+ DriveInfo *dinfo;
+
+ max_unit = -1;
+ QTAILQ_FOREACH(dinfo, &drives, next) {
+ if(dinfo->type == type &&
+ dinfo->unit > max_unit)
+ max_unit = dinfo->unit;
+ }
+ return max_unit;
+}
+
/* Get a block device. This should only be used for single-drive devices
(e.g. SD/Floppy/MTD). Multi-disk devices (scsi/ide) should use the
appropriate bus. */
diff --git a/blockdev.h b/blockdev.h
index bbd1017..250f9d8 100644
--- a/blockdev.h
+++ b/blockdev.h
@@ -61,6 +61,7 @@ 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);
+int drive_get_max_unit(BlockInterfaceType type);
DriveInfo *drive_get_next(BlockInterfaceType type);
void drive_get_ref(DriveInfo *dinfo);
void drive_put_ref(DriveInfo *dinfo);
diff --git a/hw/ide.h b/hw/ide.h
index 0b7e000..54e485f 100644
--- a/hw/ide.h
+++ b/hw/ide.h
@@ -35,11 +35,7 @@ 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);
+void ahci_drive_get(DriveInfo **hd, int max_bus, int max_ports);
#endif /* HW_IDE_H */
diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
index 824b86f..1e389aa 100644
--- a/hw/ide/ahci.c
+++ b/hw/ide/ahci.c
@@ -1261,20 +1261,3 @@ 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 044da3c..6fc2626 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -2341,18 +2341,17 @@ const VMStateDescription vmstate_ide_bus = {
}
};
-void ata_drive_get(DriveInfo **hd, int max_bus, BlockInterfaceType type)
+static void ata_drive_get(DriveInfo **hd, int max_bus, int max_devs,
+ BlockInterfaceType type)
{
int i;
- int max_devs;
- assert((type == IF_IDE) || type == IF_AHCI);
+ assert((type == IF_IDE) || (type == IF_AHCI));
- if (drive_get_max_bus(type) >= max_bus) {
+ if ((type == IF_IDE) && (drive_get_max_bus(type) >= max_bus)) {
fprintf(stderr, "qemu: too many IDE bus: %d\n", max_bus);
exit(1);
}
- 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);
}
@@ -2360,10 +2359,10 @@ void ata_drive_get(DriveInfo **hd, int max_bus,
BlockInterfaceType type)
void ide_drive_get(DriveInfo **hd, int max_bus)
{
- ata_drive_get(hd, max_bus, IF_IDE);
+ ata_drive_get(hd, max_bus, MAX_IDE_DEVS, IF_IDE);
}
-void ahci_drive_get(DriveInfo **hd, int max_bus)
+void ahci_drive_get(DriveInfo **hd, int max_bus, int max_ports)
{
- ata_drive_get(hd, max_bus, IF_AHCI);
+ ata_drive_get(hd, max_bus, max_ports, IF_AHCI);
}
diff --git a/hw/ide/pci.c b/hw/ide/pci.c
index 644533f..2df6b57 100644
--- a/hw/ide/pci.c
+++ b/hw/ide/pci.c
@@ -30,6 +30,7 @@
#include "dma.h"
#include <hw/ide/pci.h>
+#include <hw/ide/ahci.h>
#define BMDMA_PAGE_SIZE 4096
@@ -504,6 +505,24 @@ void pci_ide_create_devs(PCIDevice *dev, DriveInfo
**hd_table)
}
}
+
+void pci_ahci_create_devs(PCIDevice *pci_dev, DriveInfo **hd_table, int
table_size)
+{
+ struct AHCIPCIState *dev = DO_UPCAST(struct AHCIPCIState, card, pci_dev);
+ int i;
+ DriveInfo *drive;
+
+ for (i = 0; i < table_size; 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]);
+ }
+}
+
static const struct IDEDMAOps bmdma_ops = {
.start_dma = bmdma_start_dma,
.start_transfer = bmdma_start_transfer,
diff --git a/hw/ide/pci.h b/hw/ide/pci.h
index a694e54..6a0d500 100644
--- a/hw/ide/pci.h
+++ b/hw/ide/pci.h
@@ -58,6 +58,8 @@ void bmdma_init(IDEBus *bus, BMDMAState *bm, PCIIDEState *d);
void bmdma_cmd_writeb(BMDMAState *bm, uint32_t val);
extern MemoryRegionOps bmdma_addr_ioport_ops;
void pci_ide_create_devs(PCIDevice *dev, DriveInfo **hd_table);
+void pci_ahci_create_devs(PCIDevice *pci_dev, DriveInfo **hd_table, int
table_size);
+
extern const VMStateDescription vmstate_ide_pci;
#endif
- Re: [Qemu-devel] [PATCH v3 04/26] pci: introduce pci_swizzle_map_irq_fn() for standardized interrupt pin swizzle, (continued)
[Qemu-devel] [PATCH v3 06/26] pc: Move ioapic_init() from pc_piix.c to pc.c, Jason Baron, 2012/10/19
[Qemu-devel] [PATCH v3 08/26] pci_ids: add intel 82801BA pci-to-pci bridge id, Jason Baron, 2012/10/19
[Qemu-devel] [PATCH v3 01/26] blockdev: Introduce a default machine blockdev interface field, QEMUMachine->mach_if, Jason Baron, 2012/10/19
Re: [Qemu-devel] [PATCH v3 01/26] blockdev: Introduce a default machine blockdev interface field, QEMUMachine->mach_if, Markus Armbruster, 2012/10/24