with write_fis_d2h and signature generation tidied up,
let's adjust the initial d2h semantics to make more sense.
The initial d2h is considered delivered if there is guest
memory to save it to.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1441140641-17631-5-git-send-email-jsnow@redhat.com
It's no longer used. We used to generate a D2H FIS based
upon the command FIS that prompted the update, but in reality,
the D2H FIS is generated purely from register state.
cmd_fis is vestigial, so get rid of it.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1441140641-17631-4-git-send-email-jsnow@redhat.com
The initial register device-to-host FIS no longer needs to specially
set certain fields, as these can be handled generically by setting those
fields explicitly with the signatures we want at port reset time.
(1) Signatures are decomposed into their four component registers and
set upon (AHCI) port reset.
(2) the signature cache register is no longer set manually per-each
device type, but instead just once during ahci_init_d2h.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1441140641-17631-3-git-send-email-jsnow@redhat.com
This check is dead due to an earlier conditional.
AHCI does not currently support hotplugging, so
checks to see if devices are present or not are useless.
Remove it.
Reported-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1441140641-17631-2-git-send-email-jsnow@redhat.com
IDEState's io_buffer_offset was originally added to keep track of offsets
in AHCI rather exclusively, but it was added to IDEState instead of an
AHCI-specific structure.
AHCI fakes all PIO transfers using DMA and a scatter-gather list. When
the core or atapi layers invoke HBA-specific mechanisms for transfers,
they do not always know that it is being backed by DMA or a sglist, so
this offset is not always updated by the HBA code everywhere.
If we modify it in dma_buf_commit, however, any HBA that needs to use
this offset to manage operating on only part of a sglist will have
access to it.
This will fix ATAPI PIO transfers performed through the AHCI HBA,
which were previously not modifying this value appropriately.
This will fix ATAPI PIO transfers larger than one sector.
Reported-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Message-id: 1440546331-29087-2-git-send-email-jsnow@redhat.com
CC: qemu-stable@nongnu.org
Minor cleanup.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
The AHCIState struct can either have AHCIPCIState or SysbusAHCIState
as a parent. The ahci_irq_lower() and ahci_irq_raise() functions
assume that it is always AHCIPCIState, which is not always the
case, which causes a seg fault. Verify what the container of AHCIState
is before setting the PCIDevice struct.
Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
Acked-by: John Snow <jsnow@redhat.com>
Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Pull the AHCI state structure out into the header. This allows
other containers to access the struct. This is required to add
the device to modern SoC containers.
Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
Reviewed-by: Sai Pavan Boddu <saipava@xilinx.com>
Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
The AHCI spec requires that the HBA sets the ICC bits to zero after the
ICC change is done. Since we don't do any ICC change, force the bits to
zero all the time.
This fixes delays with some OSs (e.g. OpenBSD) waiting for the ICC bits
to change to 0.
Signed-off-by: Stefan Fritsch <sf@sfritsch.de>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: E1ZFpg7-00027N-HW@eru.sfritsch.de
Signed-off-by: John Snow <jsnow@redhat.com>
There are two things to fix here:
The first one is subtle: the PxSACT register in the AHCI HBA has different
semantics from the field it is shadowing, the ACT field in the
Set Device Bits FIS.
In the HBA register, PxSACT acts as a bitfield indicating outstanding
NCQ commands where a set bit indicates a pending NCQ operation. The FIS
field however operates as an RWC register update to PxSACT, where a set
bit indicates a *successfully* completed command.
Correct the FIS semantics. At the same time, move the "clear finished"
action to the SDB FIS generation instead of the register read to mimick
how the other shadow registers work, which always just report the last
reported value from a FIS, and not the most current values which may
not have been reported by a FIS yet.
Lastly and more simply, SATA 3.2 section 13.6.4.2 (and later sections)
all specify that the Interrupt bit for the SDB FIS should always be set
to one for NCQ commands. That's currently the only time we generate this
FIS, so set it on all the time.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1435767578-32743-16-git-send-email-jsnow@redhat.com
The Register D2H FIS should copy the current values of
the registers instead of just parroting back the same
values the guest sent back to it.
In this case, the SECTOR COUNT variables are actually
not generally meaningful in terms of standard commands
(See ATA8-AC3 Section 9.2 Normal Outputs), so it actually
probably doesn't matter what we put in here.
Meanwhile, we do need to use the Register update FIS from
the NCQ pathways (in error cases), so getting rid of
references to cur_cmd here is a win for AHCI concurrency.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1435767578-32743-14-git-send-email-jsnow@redhat.com
Migrate the NCQ queue. This is solely for the benefit of halted commands,
since anything else should have completed and had any relevant status
flushed to the HBA registers already.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1435767578-32743-13-git-send-email-jsnow@redhat.com
cur_cmd is an internal bookmark that points to the
current AHCI Command Header being processed by the
AHCI state machine. With NCQ needing to occasionally
rely on some of the same AHCI helpers, we cannot use
cur_cmd and will need to grab explicit pointers instead.
In an attempt to begin relying on the cur_cmd pointer
less, add a helper to let us specifically get the pointer
to the command header of particular interest.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1435767578-32743-12-git-send-email-jsnow@redhat.com
While the rest of the AHCI device can rely on a single bookmarked
pointer for the AHCI Command Header currently being processed, NCQ
is asynchronous and may have many commands in flight simultaneously.
Add a cmdh pointer to the ncq_tfs object and make the sglist prepare
function take an AHCICmdHeader pointer so we can be explicit about
where we'd like to build SGlists from.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1435767578-32743-11-git-send-email-jsnow@redhat.com
uint16_t isn't enough to hold the real sector count, since a value of
zero implies a full 64K sectors, so we need a uint32_t here.
We *could* cheat and pretend that this value is 0-based and fit it in
a uint16_t, but I'd rather waste 2 bytes instead of a future dev's
10 minutes when they forget to +1/-1 accordingly somewhere.
See SATA 3.2, section 13.6.4.1 "READ FPDMA QUEUED".
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1435767578-32743-9-git-send-email-jsnow@redhat.com
Handle NCQ failures for cases where we want to halt the VM on IO errors.
Upon a VM state change, retry the halted NCQ commands.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1435767578-32743-7-git-send-email-jsnow@redhat.com
When we add werror=stop or rerror=stop support to NCQ,
we'll want to take a codepath where we don't actually
complete the command, so factor that out into a new routine.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1435767578-32743-6-git-send-email-jsnow@redhat.com
Split off execute_ncq_command so that we can call
it separately later if we desire.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1435767578-32743-5-git-send-email-jsnow@redhat.com
We already checked this in the handle_cmd phase, so just
change this to an assertion and simplify the error logic.
(Also, fix the switch indent, because checkpatch.pl yelled.)
((Sorry for churn.))
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1435767578-32743-4-git-send-email-jsnow@redhat.com
For migration and werror=stop/rerror=stop resume purposes,
it will be convenient to have the command handy inside of
ncq_tfs.
Eventually, we'd like to avoid reading from the FIS entirely
after the initial read, so this is a byte (hah!) sized step
in that direction.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1435767578-32743-3-git-send-email-jsnow@redhat.com
prepare_buf should not always grab as many descriptors
as it can, sometimes it should self-limit.
For example, an NCQ transfer of 1 sector with a PRDT that
describes 4GiB of data should not copy 4GiB of data, it
should just transfer that first 512 bytes.
PIO is not affected, because the dma_buf_rw dma helpers
already have a byte limit built-in to them, but DMA/NCQ
will exhaust the entire list regardless of requested size.
AHCI 1.3 specifies in section 6.1.6 Command List Underflow that
NCQ is not required to detect underflow conditions. Non-NCQ
pathways signal underflow by writing to the PRDBC field, which
will already occur by writing the actual transferred byte count
to the PRDBC, signaling the underflow.
Our NCQ pathways aren't required to detect underflow, but since our DMA
backend uses the size of the PRDT to determine the size of the transer,
if our PRDT is bigger than the transaction (the underflow condition) it
doesn't cost us anything to detect it and truncate the PRDT.
This is a recoverable error and is not signaled to the guest, in either
NCQ or normal DMA cases.
For BMDMA, the existing pathways should see no guest-visible difference,
but any bytes described in the overage will no longer be transferred
before indicating to the guest that there was an underflow.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1435767578-32743-2-git-send-email-jsnow@redhat.com
This value should not be size-corrected, 0 sectors does not imply
1 sector(s). This is just debug information, but it's misleading!
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1435016308-6150-8-git-send-email-jsnow@redhat.com
Most of the time, these bits can be safely ignored. For the purposes
of debugging however, it's nice to know that they're not being used.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1435016308-6150-7-git-send-email-jsnow@redhat.com
There's no real reason to have it bundled together, and this way
is a little nicer to follow if you have the AHCI spec pulled up.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1435016308-6150-6-git-send-email-jsnow@redhat.com
Don't attempt the NCQ transfer if the PRDT we were given is not big
enough to perform the entire transfer.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1435016308-6150-5-git-send-email-jsnow@redhat.com
Set some appropriate error bits for NCQ for us.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1435016308-6150-4-git-send-email-jsnow@redhat.com
Trivial cleanup that I didn't want to tack-on to anything else.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1435016308-6150-3-git-send-email-jsnow@redhat.com
The only guidance the AHCI specification gives on memory access is:
"Register accesses shall have a maximum size of 64-bits; 64-bit access
must not cross an 8-byte alignment boundary."
I interpret this to mean that aligned or unaligned 1, 2 and 4 byte
accesses should work, as well as aligned 8 byte accesses.
In practice, a real Q35/ICH9 responds to 1, 2, 4 and 8 byte reads
regardless of alignment. Windows 7 can be observed making 1 byte
reads to the middle of 32 bit registers to fetch error codes.
Introduce a wrapper to support unaligned accesses to AHCI.
This wrapper will support aligned 8 byte reads, but will make
no effort to support unaligned 8 byte reads, which although they
will work on real hardware, are not guaranteed to work and do
not appear to be used by either Windows or Linux.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1434470575-21625-2-git-send-email-jsnow@redhat.com
In particular, don't include it into headers.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
This continues the IOMMU fix from 2.3, where we should not attempt
to remap the CLB or FIS RX buffers if the AHCI device is currently
running.
The same applies to migration: keep our mitts off these registers
unless the device is supposed to be on.
Does not impact backwards compatibility for the AHCI device.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1431470173-30847-2-git-send-email-jsnow@redhat.com
Lift the flag preventing the migration of the ICH9/AHCI devices.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 1430417242-11859-5-git-send-email-jsnow@redhat.com
Many bits in the CMD register are supposed to be strictly read-only.
We should not be deleting them on every write.
As a side-effect: pay explicit attention to when a guest marks off
the FIS Receive or Start bits, and disable the status bits ourselves,
instead of letting them implicitly fall off.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1426283454-15590-3-git-send-email-jsnow@redhat.com
The FIS Receive Buffer and Command List Buffer pointers
should not be edited while the FIS receive engine or
Command Receive engines are running.
Currently, we attempt to re-map the buffers every time they
are adjusted, but while the AHCI engines are off, these registers
may contain stale values, so we should not attempt to re-map these
values until the engines are reactivated.
Reported-by: Jordan Hargrave <jharg93@gmail.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1426283454-15590-2-git-send-email-jsnow@redhat.com
This does not bother DMA, because DMA generally transfers
the entire SGList in one shot if it can.
PIO, on the other hand, tries to transfer just one sector
at a time, and will make multiple visits to the sglist
to fetch memory addresses.
Fix the memory address calculaton when we have an offset
by moving the offset addition OUTSIDE of the le64_to_cpu
calculation.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Tested-by: Andreas Färber <afaerber@suse.de>
Message-id: 1426811056-2202-4-git-send-email-jsnow@redhat.com
When the AHCI HBA device is migrated, all of the information that
led to the request being created is stored in the AHCIDevice
structures, except for pointers into guest data where return
information needs to be stored.
The "cur_cmd" field is usually responsible for this.
To rebuild the cur_cmd pointer post-migration, we can utilize
the busy_slot index to figure out where the command header
we are still processing is.
This allows a machine in a halted state from rerror=stop or
werror=stop to be migrated and resume operations without issue.
Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 1424708286-16483-17-git-send-email-jsnow@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This is easy, since start_dma already restarts processing from the
beginning of the PRDT.
Migration is also easy to cover; the comment about busy_slot is
wrong, busy_slot will only be set if there is an error. In this
case we have nothing to do really. The core IDE code will restart
the operation and command list processing will proceed after the
erroring command has been completed.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 1424708286-16483-16-git-send-email-jsnow@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Amazingly, we weren't doing this before.
Make sure we migrate the IDEState structure that belongs to
the AHCIDevice.IDEBus structure during migrations.
No version numbering changes because AHCI is not officially
migratable (and we can all see with good reason why) so we
do not impact any official builds by altering the stream and
leaving it at version 1.
This fixes the rerror=stop/werror=stop test case where we wish
to migrate a halted job. Previously, the error code would not
migrate, so even if the job completed successfully, AHCI would
report an error because it would still have the placeholder
error code from initialization time.
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 1424708286-16483-15-git-send-email-jsnow@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Start moving the initial state of the current request to IDEBus, so that
AHCI can use it. The set_unit callback is not used anymore once this is
done.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 1424708286-16483-9-git-send-email-jsnow@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
With restarts now handled by ide_restart_cb and
the IDEDMAOps.restart_dma() member, remove the old
restart_cb callback.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 1424708286-16483-8-git-send-email-jsnow@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
SATA 3.0 "10.3.1 FIS Type values" defines the constants used to
differentiate between FIS types.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 1415874281-7371-3-git-send-email-stefanha@redhat.com
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Debug code using #ifdef is susceptible to bitrot because the compiler
never checks the debug code.
This is easy to avoid, change the DPRINTF() macro to use if (DEBUG_AHCI)
and always give it a 0 or 1 value.
This also allows us to drop an #ifdef DEBUG_AHCI in ahci_start_dma()
since the compiler can now see the local variable is used.
The motivation for this change is a recent DEBUG_AHCI build failure due
to an outdated DPRINTF() format string. From now on the compiler will
catch these errors.
Cc: John Snow <jsnow@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 1415874281-7371-2-git-send-email-stefanha@redhat.com
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
In order to make handle_cmd more readable at the macro level,
the details of how to decompose particular types of FIS packets
are left to helper functions.
In our case, the only type of FIS packet we currently expect to
see is a Register H2D FIS packet, but the gory details of its
decomposition are of no particular interest in handle_cmd.
This patch keeps the receipt of FIS packets and the decomposition
thereof separated to two different functions.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1415058979-16604-6-git-send-email-jsnow@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Instead of checking for a known byte, inspect the
fields of this byte explicitly to produce more meaningful
error messages and improve the readability of this section.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1415058979-16604-5-git-send-email-jsnow@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Error checking in ahci's handle_cmd is re-ordered so that we
initialize as few things as possible before we've done our
sanity checking. This simplifies returning from this call
in case of an error.
A check to make sure the DMA memory map succeeds with the
correct size is also added, and the debug print of the
command fis is cleaned up with its size corrected.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1415058979-16604-4-git-send-email-jsnow@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This patch introduces a few changes to how FIS packets are
deciphered in the AHCI virtual device. The summary of
changes can be grouped into two pieces:
[A] Changes to how we apply a preliminary sieve to FISes,
[B] Changes in how we internalize a decomposed FIS.
== Changes to how we apply a preliminary sieve to FISes ==
(1) Packets may now either update the Control register or
the Command register, but not both. This is according
to the SATA 3.2 specification which states:
"...the device either initiates processing of the command
indicated in the Command register or initiates processing
of the control request indicated [...] depending on the
state of the C bit in the FIS."
See SATA 3.2 section 10.5.5.4, "Reception" in the 10.5.5
"Register Host to Device FIS" section.
This change accounts for the first two regions of change
within the diff. All other changes belong to the following
changes.
== Changes in how we internalize a decomposed FIS ==
(2) Instead of trying to extract the sector number out of the
FIS from bytes 4-10 and setting it with ide_set_sector,
we set the appropriate IDEState registers and trust that
ide_get_sector can retrieve the correct sector later.
By "constructing" the sector for use with ide_set_sector,
we are duplicating the mechanisms of ide_get_sector.
This change makes the FIS decomposition more obvious.
SATA 3.2 as a specification does not make the legacy
register mapping with respect to the D2H FIS obvious.
However, SATA 3.2 section 10.5.5.1 "Register Host to
Device FIS layout" describes all of the "cmd_fis"
bytes:
0 - FIS Type (0x27)
1 - Port Multiplier Port and Command Update flag
2 - ATA Command
3 - Features_Low
4 - LBA 7:0
5 - LBA 15:8
6 - LBA 23:16
7 - Device, AKA "Drive Select."
8 - LBA 31:24
9 - LBA 39:32
10 - LBA 47:40
11 - Features_High
12 - Count Low
13 - Count High
14 - ICC
15 - Control
16-19 - Auxiliary (for NCQ, defined per-command)
Most of these registers map to existing IDEState registers
in obvious ways, especially features, select, hob_features,
and nsector (count). ICC is reserved in older specifications
but is not supported in our implementation, and remains
unused here. The Control register is not valid for a command
that is trying to update the command register and is to be
considered reserved at this point.
What is not obvious is the LBA register mappings, but SATA 1.0
can help inform of us legacy device support, see SATA 1.0 section
8.5.2 "Register - Host to Device."
LBA 7:0 - Sector Number (sector)
LBA 15:8 - Cyl Low (lcyl)
LBA 23:16 - Cyl High (hcyl)
LBA 31:24 - Sector Num Exp. (hob_sector)
LBA 39:32 - Cyl Low Exp. (hob_lcyl)
LBA 47:40 - Cyl High Exp. (hob_hcyl)
These mappings help guide which registers the FIS should be decomposed
into/towards for CHS, LBA28 and LBA48 commands.
As a note: The prior confusion that can be seen in the documentation
arises from the fact that CHS and LBA28 commands use the low nybble
of the drive select register to store LBA 27:24, whereas LNA48 commands
use the hob_sector, hob_lcyl and hob_hcyl registers as explained above.
The decomposition as it stands now will correctly decompose CHS, LBA28
and LBA48 commands into their appropriate registers where the core
IDE/ATAPI layers can deal with them correctly.
See the below point for more information.
(3) We save cmd_fis[7] as ide_state->select, which informs
decisions about if we are using LBA or CHS.
This corrects a bug in AHCI wherein we attempt to set and/or
retrieve the sector number by using ide_set_sector and
ide_get_sector, which depend on the select register to
determine if we are using LBA or CHS.
Without this adjustment, LBA48 read/writes are currently
broken. Thanks to Eniac Zheng @ HP for pointing this out.
(4) Save cmd_fis[11] as ide_state->hob_feature, as defined in SATA 3.2.
(5) For several ATA commands, the sector count register set to 0
is a magic number that means 256 sectors. For LBA48 commands,
this means 65,536 sectors. We drop the magic sector correction
here, and trust the ide core layer to handle the conversion
appropriately, in ide_cmd_lba48_transform(). As it stands,
the current AHCI code is only compliant with LBA28 commands.
By simply removing the magic, it will work with LBA28 and LBA48.
(6) We expand FIS decomposition to include both ATAPI and IDE devices.
We leave the logic of determining if the fields are valid or not
to the respective layers.
This change intends to make it clearer that AHCI is only a
composition mechanism for the FIS packets: the meanings of
the registers is best left to the implementation layers for
those devices.
(7) Forcefully setting the feature, hcyl and lcyl registers for ATAPI
commands is removed.
- The hcyl and lcyl magic present here is valid at boot only,
and should not be overridden for every PACKET command.
- The feature register is defined as valid for the PACKET command,
so we should not suppress it. The ATAPI layer does not even
currently depend on or require 0x01 as mandatory.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1415058979-16604-3-git-send-email-jsnow@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
A small helper to determine which S/ATA commands
are destined to be routed to the NCQ pathways.
This references SATA 3.2 section 13.6,
Native Command Queueing. See sections 13.6.4,
13.6.5, 13.6.6, 13.6.7 and 13.6.8 for all
SATA commands considered to be part of the
NCQ feature set. This is summarized in a small
list in section 13.6.3.1 and again in 13.6.3.2.
Not all of these NCQ commands are currently supported,
so the error pathways are adjusted slightly to be more
informative in the case they are encountered.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1415058979-16604-2-git-send-email-jsnow@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This impacts both BMDMA and AHCI HBA interfaces for IDE.
Currently, we confuse the difference between a PRDT having
"0 bytes" and a PRDT having "0 complete sectors."
When we receive an incomplete sector, inconsistent error checking
leads to an infinite loop wherein the call succeeds, but it
didn't give us enough bytes -- leading us to re-call the
DMA chain over and over again. This leads to, in the BMDMA case,
leaked memory for short PRDTs, and infinite loops and resource
usage in the AHCI case.
The .prepare_buf() callback is reworked to return the number of
bytes that it successfully prepared. 0 is a valid, non-error
answer that means the table was empty and described no bytes.
-1 indicates an error.
Our current implementation uses the io_buffer in IDEState to
ultimately describe the size of a prepared scatter-gather list.
Even though the AHCI PRDT/SGList can be as large as 256GiB, the
AHCI command header limits transactions to just 4GiB. ATA8-ACS3,
however, defines the largest transaction to be an LBA48 command
that transfers 65,536 sectors. With a 512 byte sector size, this
is just 32MiB.
Since our current state structures use the int type to describe
the size of the buffer, and this state is migrated as int32, we
are limited to describing 2GiB buffer sizes unless we change the
migration protocol.
For this reason, this patch begins to unify the assertions in the
IDE pathways that the scatter-gather list provided by either the
AHCI PRDT or the PCI BMDMA PRDs can only describe, at a maximum,
2GiB. This should be resilient enough unless we need a sector
size that exceeds 32KiB.
Further, the likelihood of any guest operating system actually
attempting to transfer this much data in a single operation is
very slim.
To this end, the IDEState variables have been updated to more
explicitly clarify our maximum supported size. Callers to the
prepare_buf callback have been reworked to understand the new
return code, and all versions of the prepare_buf callback have
been adjusted accordingly.
Lastly, the ahci_populate_sglist helper, relied upon by the
AHCI implementation of .prepare_buf() as well as the PCI
implementation of the callback have had overflow assertions
added to help make clear the reasonings behind the various
type changes.
[Added %d -> %"PRId64" fix John sent because off_pos changed from int to
int64_t.
--Stefan]
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1414785819-26209-4-git-send-email-jsnow@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The intent of this patch is to further unify the creation and
deletion of the sglist used for all AHCI transfers, including
emulated PIO, ATAPI R/W, and native DMA R/W.
By replacing ahci_start_transfer's call to ahci_populate_sglist
with ahci_dma_prepare_buf, we reduce the number of direct calls
where we manipulate the scatter-gather list in the AHCI code.
To make this switch, the constant "0" passed as an offset
in ahci_dma_prepare_buf is adjusted to use io_buffer_offset.
For DMA pathways, this has no effect: io_buffer_offset is always
updated to 0 at the beginning of a DMA transfer loop regardless.
DMA pathways through ide_dma_cb() update the io_buffer_offset
accordingly, and for circumstances where we might make several
trips through this loop, this may actually correct a design flaw.
For PIO pathways, the newly updated ahci_dma_prepare_buf will
now prepare the sglist at the correct offset. It will also set
io_buffer_size, but this is not used in the cmd_read_pio or
cmd_write_pio pathways.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1414785819-26209-3-git-send-email-jsnow@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
