Commit Graph

359 Commits

Author SHA1 Message Date
royger
0d6c943749 xen: add the Xen implementation of pci_child_added method
Add the Xen specific implementation of pci_child_added to the Xen PCI
bus. This is needed so FreeBSD can register the devices it finds with
the hypervisor.

Sponsored by: Citrix Systems R&D

x86/xen/xen_pci.c:
 - Add the Xen pci_child_added method.
2014-09-30 16:49:17 +00:00
royger
c5a5f5947f msi: add Xen MSI implementation
This patch adds support for MSI interrupts when running on Xen. Apart
from adding the Xen related code needed in order to register MSI
interrupts this patch also makes the msi_init function a hook in
init_ops, so different MSI implementations can have different
initialization functions.

Sponsored by: Citrix Systems R&D

xen/interface/physdev.h:
 - Add the MAP_PIRQ_TYPE_MULTI_MSI to map multi-vector MSI to the Xen
   public interface.

x86/include/init.h:
 - Add a hook for setting custom msi_init methods.

amd64/amd64/machdep.c:
i386/i386/machdep.c:
 - Set the default msi_init hook to point to the native MSI
   initialization method.

x86/xen/pv.c:
 - Set the Xen MSI init hook when running as a Xen guest.

x86/x86/local_apic.c:
 - Call the msi_init hook instead of directly calling msi_init.

xen/xen_intr.h:
x86/xen/xen_intr.c:
 - Introduce support for registering/releasing MSI interrupts with
   Xen.
 - The MSI interrupts will use the same PIC as the IO APIC interrupts.

xen/xen_msi.h:
x86/xen/xen_msi.c:
 - Introduce a Xen MSI implementation.

x86/xen/xen_nexus.c:
 - Overwrite the default MSI hooks in the Xen Nexus to use the Xen MSI
   implementation.

x86/xen/xen_pci.c:
 - Introduce a Xen specific PCI bus that inherits from the ACPI PCI
   bus and overwrites the native MSI methods.
 - This is needed because when running under Xen the MSI messages used
   to configure MSI interrupts on PCI devices are written by Xen
   itself.

dev/acpica/acpi_pci.c:
 - Lower the quality of the ACPI PCI bus so the newly introduced Xen
   PCI bus can take over when needed.

conf/files.i386:
conf/files.amd64:
 - Add the newly created files to the build process.
2014-09-30 16:46:45 +00:00
royger
890b160ee5 xen: add proper copyright attribution
Noted by:	jmallett
2014-09-26 09:05:55 +00:00
royger
494dc32ba6 ddb: allow specifying the exact address of the symtab and strtab
When the FreeBSD kernel is loaded from Xen the symtab and strtab are
not loaded the same way as the native boot loader. This patch adds
three new global variables to ddb that can be used to specify the
exact position and size of those tables, so they can be directly used
as parameters to db_add_symbol_table. A new helper is introduced, so callers
that used to set ksym_start and ksym_end can use this helper to set the new
variables.

It also adds support for loading them from the Xen PVH port, that was
previously missing those tables.

Sponsored by: Citrix Systems R&D
Reviewed by:	kib

ddb/db_main.c:
 - Add three new global variables: ksymtab, kstrtab, ksymtab_size that
   can be used to specify the position and size of the symtab and
   strtab.
 - Use those new variables in db_init in order to call db_add_symbol_table.
 - Move the logic in db_init to db_fetch_symtab in order to set ksymtab,
   kstrtab, ksymtab_size from ksym_start and ksym_end.

ddb/ddb.h:
 - Add prototype for db_fetch_ksymtab.
 - Declate the extern variables ksymtab, kstrtab and ksymtab_size.

x86/xen/pv.c:
 - Add support for finding the symtab and strtab when booted as a Xen
   PVH guest. Since Xen loads the symtab and strtab as NetBSD expects
   to find them we have to adapt and use the same method.

amd64/amd64/machdep.c:
arm/arm/machdep.c:
i386/i386/machdep.c:
mips/mips/machdep.c:
pc98/pc98/machdep.c:
powerpc/aim/machdep.c:
powerpc/booke/machdep.c:
sparc64/sparc64/machdep.c:
 - Use the newly introduced db_fetch_ksymtab in order to set ksymtab,
   kstrtab and ksymtab_size.
2014-09-25 08:28:10 +00:00
neel
46721cc2c7 Restructure the MSR handling so it is entirely handled by processor-specific
code. There are only a handful of MSRs common between the two so there isn't
too much duplicate functionality.

The VT-x code has the following types of MSRs:

- MSRs that are unconditionally saved/restored on every guest/host context
  switch (e.g., MSR_GSBASE).

- MSRs that are restored to guest values on entry to vmx_run() and saved
  before returning. This is an optimization for MSRs that are not used in
  host kernel context (e.g., MSR_KGSBASE).

- MSRs that are emulated and every access by the guest causes a trap into
  the hypervisor (e.g., MSR_IA32_MISC_ENABLE).

Reviewed by:	grehan
2014-09-20 02:35:21 +00:00
adrian
e4c630d701 Migrate ie->ie_assign_cpu and associated code to use an int for CPU rather
than u_char.

Migrate post_filter to use an int for a CPU rather than u_char.

Change intr_event_bind() to use an int for CPU rather than u_char.

It touches the ppc, sparc64, arm and mips machdep code but it should
(hah!) be a no-op.

Tested:

* i386, AMD64 laptops

Reviewed by:	jhb
2014-09-17 17:33:22 +00:00
royger
522c50de15 xen: don't set suspend/resume methods for the PIRQ PIC
The suspend/resume of event channels is already handled by the xen_intr_pic.
If those methods are set on the PIRQ PIC they are just called twice, which
breaks proper resume. This fix restores migration of FreeBSD guests to a
working state.

Sponsored by: Citrix Systems R&D
2014-09-15 15:15:52 +00:00
jhb
6f8d6cd57b To workaround an errata on certain Pentium Pro CPUs, i386 disables
the local APIC in initializecpu() and re-enables it if the APIC code
decides to use the local APIC after all.  Rework this workaround
slightly so that initializecpu() won't re-disable the local APIC if
it is called after the APIC code re-enables the local APIC.
2014-09-10 21:25:54 +00:00
jhb
2a48d5d52c Move code to set various MSRs on AMD cpus out of printcpuinfo() and
into initalizecpu() instead.
2014-09-10 21:04:44 +00:00
kib
409097f5b7 Add a define for index of IA32_XSS MSR, which is, per SDM rev. 50, an
analog of XCR0 for ring 0 FPU state, used by XSAVES and XRSTORS.

Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2014-09-06 19:47:37 +00:00
kib
a52df371a9 SDM rev. 50 defines the use of the next 8 bytes in the xstate header.
It is the compaction bitmask, with the highest bit defining if compact
format of the xsave area is used at all.

Adjust the definition of struct xstate_hdr, provide define for bit 63.

Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2014-09-06 19:39:12 +00:00
kib
51e3f3be5c Add more bits for the XSAVE features from CPUID 0xd, sub-function 1
%eax report.

Print the XSAVE features 0xd/1 in the boot banner.  The printcpuinfo()
is executed late enough so that XSAVE is already enabled.

There is no known to me off the shelf hardware that implements any
feature bits except XSAVEOPT, the list is taken from SDM rev. 50.  The
banner printing will allow us to note the hardware arrival.

Sponsored by:	    The FreeBSD Foundation
MFC after:	    1 week
2014-09-06 15:45:45 +00:00
jhb
3a8cf1a38b Create a separate structure for per-CPU state saved across suspend and
resume that is a superset of a pcb.  Move the FPU state out of the pcb and
into this new structure.  As part of this, move the FPU resume code on
amd64 into a C function.  This allows resumectx() to still operate only on
a pcb and more closely mirrors the i386 code.

Reviewed by:	kib (earlier version)
2014-09-06 15:23:28 +00:00
jhb
f7c94cc497 Merge the amd64 and i386 identcpu.c into a single x86 implementation.
This brings the structured extended features mask and VT-x reporting to
i386 and Intel cache and TLB info (under bootverbose) to amd64.
2014-09-04 14:26:25 +00:00
jhb
f937116d20 - Move blacklists of broken TSCs out of the printcpuinfo() function
and into the TSC probe routine.
- Initialize cpu_exthigh once in finishidentcpu() which is called
  before printcpuinfo() (and matches the behavior on amd64).
2014-09-04 02:25:59 +00:00
jhb
59920f0385 Save and restore FPU state across suspend and resume. In earlier revisions
of this patch, resumectx() called npxresume() directly, but that doesn't
work because resumectx() runs with a non-standard %cs selector.  Instead,
all of the FPU suspend/resume handling is done in C.

MFC after:	1 week
2014-08-30 17:48:38 +00:00
royger
c934f5fd28 atpic: make sure atpic_init is called after IO APIC initialization
After r269510 the IO APIC and ATPIC initialization is done at the same
order, which means atpic_init can be called before the IO APIC has
been initalized. In that case the ATPIC will take over the interrupt
sources, preventing the IO APIC from registering them.

Reported by: David Wolfskill <david@catwhisker.org>
Tested by: David Wolfskill <david@catwhisker.org>,
           Trond Endrestøl <Trond.Endrestol@fagskolen.gjovik.no>
Sponsored by: Citrix Systems R&D
2014-08-07 17:00:50 +00:00
royger
8daf97263e xen: add ACPI bus to xen_nexus when running as Dom0
Also disable a couple of ACPI devices that are not usable under Dom0.
To this end a couple of booleans are added that allow disabling ACPI
specific devices.

Sponsored by: Citrix Systems R&D
Reviewed by: jhb

x86/xen/xen_nexus.c:
 - Return BUS_PROBE_SPECIFIC in the Xen Nexus attachement routine to
   force the usage of the Xen Nexus.
 - Attach the ACPI bus when running as Dom0.

dev/acpica/acpi_cpu.c:
dev/acpica/acpi_hpet.c:
dev/acpica/acpi_timer.c
 - Add a variable that gates the addition of the devices.

x86/include/init.h:
 - Declare variables that control the attachment of ACPI cpu, hpet and
   timer devices.
2014-08-04 09:05:28 +00:00
royger
937cdd0a36 xen: implement support for mapping IO APIC interrupts on Xen
Allow a privileged Xen guest (Dom0) to parse the MADT ACPI interrupt
overrides and register them with the interrupt subsystem.

Also add a Xen specific implementation for bus_config_intr that
registers interrupts on demand for all the vectors less than
FIRST_MSI_INT.

Sponsored by: Citrix Systems R&D

x86/xen/pvcpu_enum.c:
 - Use helper functions from x86/acpica/madt.c in order to parse
   interrupt overrides from the MADT.
 - Walk the MADT and register any interrupt override with the
   interrupt subsystem.

x86/xen/xen_nexus.c:
 - Add a custom bus_config_intr method for Xen that intercepts calls
   to configure unset interrupts and registers them on the fly (if the
   vector is < FIRST_MSI_INT).
2014-08-04 09:01:21 +00:00
royger
afa7324d1a x86/madt: make the interrupt override parser a public function
Split a portion of the code in madt_parse_interrupt_override to a
separate function, that is public and can be used from other code.
This will be needed by the Xen port, since FreeBSD needs to parse the
interrupt overrides and notify Xen about them.

This commit should not introduce any functional change.

Sponsored by: Citrix Systems R&D
Reviewed by: jhb, gibbs

x86/acpica/madt.c:
 - Introduce madt_parse_interrupt_values() that parses the intr
   information from ACPI and returns the triggering and the polarity.
   This is a subset of the functionality that used to be part of
   madt_parse_interrupt_override().
 - Make madt_found_sci_override a global variable that can be used
   from other files.

x86/include/acpica_machdep.h:
 - Prototype of madt_parse_interrupt_values.
 - Extern declaration of madt_found_sci_override.
2014-08-04 08:58:50 +00:00
royger
668dd4b0cb xen: change quality of the MADT ACPI enumerator
Lower the quality of the MADT ACPI enumerator, so on Xen Dom0 we can
force the usage of the Xen mptable enumerator even when ACPI is
detected.

This is needed because Xen might restrict the number of vCPUs
available to Dom0, but the MADT ACPI table parsed in FreeBSD is the
native one (which enumerates all the CPUs available in the system).

Sponsored by: Citrix Systems R&D
Reviewed by: gibbs

x86/acpica/madt.c:
 - Lower MADT enumerator quality to -50.

x86/xen/pvcpu_enum.c:
 - Rise Xen PV enumerator to 0.
2014-08-04 08:56:20 +00:00
royger
1bfb01ea6b xen: change order of Xen intr init and IO APIC registration
This change inserts the Xen interrupt subsystem (event channels)
initialization between the system interrupt initialization and the IO
APIC source registration.

This is needed when running on Dom0, that routes physical interrupts
on top of event channels, so that the interrupt sources found during
IO APIC initialization can be registered using the Xen interrupt
subsystem.

The resulting order in the SI_SUB_INTR stage is the following:

- System intr initialization
- Xen intr initalization
- IO APIC source registration

Sponsored by: Citrix Systems R&D

x86/x86/local_apic.c:
 - Change order of apic_setup_io to be called after xen interrupt
   subsystem is setup.

x86/xen/xen_intr.c:
 - Init Xen event channels before apic_setup_io.
2014-08-04 08:54:34 +00:00
royger
3c669f2b53 xen: add a DDB command to print event channel information
Add a new DDB command to dump all registered event channels.

Sponsored by: Citrix Systems R&D

x86/xen/xen_intr.c:
 - Add a new xen_evtchn command to DDB in order to dump all
   information related to event channels.
2014-08-04 08:52:10 +00:00
royger
8d27fa514f xen: mask all event channels on init
Mask all event channels during initialization. This is done so that we
don't receive spurious interrupts while dynamically registering new
event channels. There's a small window during registration where an
event channel can fire before we have attached a handler to it.

Sponsored by: Citrix Systems R&D

x86/xen/xen_intr.c:
 - Mask all event channels on init.
2014-08-04 08:43:27 +00:00
royger
eb7b09e785 xen: implement event channel PIRQ support
This allows Dom0 to manage physical hardware, redirecting the
physical interrupts to event channels.

Sponsored by: Citrix Systems R&D

x86/xen/xen_intr.c:
 - Expand struct xenisrc to hold the level and triggering of PIRQ
   event channels.
 - Implement missing methods in xen_intr_pirq_pic.
 - Allow xen_intr_alloc_isrc to take a vector parameter that globally
   identifies the interrupt. This is only used for PIRQs that are
   bound to a specific hardware IRQ.
 - Introduce xen_register_pirq used to register IO APIC legacy PIRQ
   interrupts.
 - Add support for the dynamic PIRQ EOI map, this shared memory is
   modified by Xen (if it suppoorts that feature), and notifies the
   guest if an EOI is needed or not. If it's not available fall back
   to the old implementation using PHYSDEVOP_irq_status_query.
 - Rename xen_intr_isrc_count to xen_intr_auto_vector_count and
   replace it's usages.
 - Align static variables by name.

xen/xen_intr.h:
 - Add prototype for xen_register_pirq.
2014-08-04 08:42:29 +00:00
jhb
05d21354c3 - Output a summary of optional VT-x features in dmesg similar to CPU
features.  If bootverbose is enabled, a detailed list is provided;
  otherwise, a single-line summary is displayed.
- Add read-only sysctls for optional VT-x capabilities used by bhyve
  under a new hw.vmm.vmx.cap node. Move a few exiting sysctls that
  indicate the presence of optional capabilities under this node.

CR:		https://phabric.freebsd.org/D498
Reviewed by:	grehan, neel
MFC after:	1 week
2014-07-30 00:00:12 +00:00
marius
0af32d8345 Fix yet another comment typo in r269052. 2014-07-29 14:54:23 +00:00
marius
2ff80e0967 Fix comment typo in r269052.
Submitted by:	Daniel O'Connor
2014-07-29 13:26:24 +00:00
akiyama
966a1bc8d6 Add missing newline to output dmesg properly. 2014-07-28 13:47:02 +00:00
gavin
b01aa1f6d0 Add error return to dumpsys(), and use it in doadump().
This commit does not add error returns to minidumpsys() or
textdump_dumpsys(); those can also be added later.

Submitted by:	Conrad Meyer (EMC / Isilon storage division)
2014-07-25 23:52:53 +00:00
marius
34c6aed3e2 Intel desktop Haswell CPUs may report benign corrected parity errors (see
HSD131 erratum in [1]) at a considerable rate. So filter these (default),
unless logging is enabled. Unfortunately, there really is no better way to
reasonably implement suppressing these errors than to just skipping them
in mca_log(). Given that they are reported for bank 0, they'd need to be
masked in MSR_MC0_CTL. However, P6 family processors require that register
to be set to either all 0s or all 1s, disabling way more than the one error
in question when using all 0s there. Alternatively, it could be masked for
the corresponding CMCI, but that still wouldn't keep the periodic scanner
from detecting these spurious errors. Apart from that, register contents of
MSR_MC0_CTL{,2} don't seem to be publicly documented, neither in the Intel
Architectures Developer's Manual nor in the Haswell datasheets.

Note that while HSD131 actually is only about C0-stepping as of revision
014 of the Intel desktop 4th generation processor family specification
update, these corrected errors also have been observed with D0-stepping
aka "Haswell Refresh".

1: http://www.intel.de/content/dam/www/public/us/en/documents/specification-updates/4th-gen-core-family-desktop-specification-update.pdf

Reviewed by:	jhb
MFC after:	3 days
Sponsored by:	Bally Wulff Games & Entertainment GmbH
2014-07-24 10:14:51 +00:00
jhb
17d78db27b Fix build with SMP disabled.
CR:		https://phabric.freebsd.org/D407
Reviewed by:	royger
2014-07-15 15:40:33 +00:00
marcel
9f28abd980 Remove ia64.
This includes:
o   All directories named *ia64*
o   All files named *ia64*
o   All ia64-specific code guarded by __ia64__
o   All ia64-specific makefile logic
o   Mention of ia64 in comments and documentation

This excludes:
o   Everything under contrib/
o   Everything under crypto/
o   sys/xen/interface
o   sys/sys/elf_common.h

Discussed at: BSDcan
2014-07-07 00:27:09 +00:00
hselasky
35b126e324 Pull in r267961 and r267973 again. Fix for issues reported will follow. 2014-06-28 03:56:17 +00:00
gjb
fc21f40567 Revert r267961, r267973:
These changes prevent sysctl(8) from returning proper output,
such as:

 1) no output from sysctl(8)
 2) erroneously returning ENOMEM with tools like truss(1)
    or uname(1)
 truss: can not get etype: Cannot allocate memory
2014-06-27 22:05:21 +00:00
hselasky
bd1ed65f0f Extend the meaning of the CTLFLAG_TUN flag to automatically check if
there is an environment variable which shall initialize the SYSCTL
during early boot. This works for all SYSCTL types both statically and
dynamically created ones, except for the SYSCTL NODE type and SYSCTLs
which belong to VNETs. A new flag, CTLFLAG_NOFETCH, has been added to
be used in the case a tunable sysctl has a custom initialisation
function allowing the sysctl to still be marked as a tunable. The
kernel SYSCTL API is mostly the same, with a few exceptions for some
special operations like iterating childrens of a static/extern SYSCTL
node. This operation should probably be made into a factored out
common macro, hence some device drivers use this. The reason for
changing the SYSCTL API was the need for a SYSCTL parent OID pointer
and not only the SYSCTL parent OID list pointer in order to quickly
generate the sysctl path. The motivation behind this patch is to avoid
parameter loading cludges inside the OFED driver subsystem. Instead of
adding special code to the OFED driver subsystem to post-load tunables
into dynamically created sysctls, we generalize this in the kernel.

Other changes:
- Corrected a possibly incorrect sysctl name from "hw.cbb.intr_mask"
to "hw.pcic.intr_mask".
- Removed redundant TUNABLE statements throughout the kernel.
- Some minor code rewrites in connection to removing not needed
TUNABLE statements.
- Added a missing SYSCTL_DECL().
- Wrapped two very long lines.
- Avoid malloc()/free() inside sysctl string handling, in case it is
called to initialize a sysctl from a tunable, hence malloc()/free() is
not ready when sysctls from the sysctl dataset are registered.
- Bumped FreeBSD version to indicate SYSCTL API change.

MFC after:	2 weeks
Sponsored by:	Mellanox Technologies
2014-06-27 16:33:43 +00:00
hselasky
e34bd25949 Fix compile warning: Remove duplicate external declaration. 2014-06-19 05:06:24 +00:00
royger
4f6426a64f xen: fix out-of-bounds access to ipi_handle
Fix the gate in xen_pv_lapic_ipi_vectored to prevent access to element
at position nitems(xen_ipis).

Sponsored by: Citrix Systems R&D
Coverity ID: 1223203
Approved by: gibbs
2014-06-18 13:41:20 +00:00
kib
0b024c9158 Do not reference native_lapic_ipi_*() functions in the UP build.
The functions' definitions are protected by #ifdef SMP.
Keeping apic_ops.ipi_*() methods NULL would allow to catch the use
on UP machines.

Reviewed by:	royger
Sponsored by:	The FreeBSD Foundation
2014-06-17 09:33:22 +00:00
royger
ac5689b414 xen: add missing files
Commit missing files that actually belong to previous commits.

Sponsored by: Citrix Systems R&D
Approved by: gibbs
2014-06-16 08:54:04 +00:00
royger
152e3229be isa: allow ISA bus to attach to xenpv bus
This is needed because syscons depends on ISA.

Sponsored by: Citrix Systems R&D
Approved by: gibbs

x86/isa/isa.c:
 - Allow the ISA bus to attach to xenpv.
2014-06-16 08:49:16 +00:00
royger
a2b989a585 xen: add hooks for Xen PV APIC
Create the necessary hooks in order to provide a Xen PV APIC
implementation that can be used on PVH. Most of the lapic ops
shouldn't be called on Xen, since we trap those operations at a higher
layer.

Sponsored by: Citrix Systems R&D
Approved by: gibbs

x86/xen/hvm.c:
x86/xen/xen_apic.c:
 - Move IPI related code to xen_apic.c

x86/xen/xen_apic.c:
 - Introduce Xen PV APIC implementation, most of the functions of the
   lapic interface should never be called when running as PV(H) guest,
   so make sure FreeBSD panics when trying to use one of those.
 - Define the Xen APIC implementation in xen_apic_ops.

xen/xen_pv.h:
 - Extern declaration of the xen_apic struct.

x86/xen/pv.c:
 - Use xen_apic_ops as apic_ops when running as PVH guest.

conf/files.amd64:
conf/files.i386:
 - Include the xen_apic.c file in the build of i386/amd64 kernels
   using XENHVM.
2014-06-16 08:43:45 +00:00
royger
7c7f3fb2d0 amd64/i386: introduce APIC hooks for different APIC implementations.
This is needed for Xen PV(H) guests, since there's no hardware lapic
available on this kind of domains. This commit should not change
functionality.

Sponsored by: Citrix Systems R&D
Reviewed by: jhb
Approved by: gibbs

amd64/include/cpu.h:
amd64/amd64/mp_machdep.c:
i386/include/cpu.h:
i386/i386/mp_machdep.c:
 - Remove lapic_ipi_vectored hook from cpu_ops, since it's now
   implemented in the lapic hooks.

amd64/amd64/mp_machdep.c:
i386/i386/mp_machdep.c:
 - Use lapic_ipi_vectored directly, since it's now an inline function
   that will call the appropiate hook.

x86/x86/local_apic.c:
 - Prefix bare metal public lapic functions with native_ and mark them
   as static.
 - Define default implementation of apic_ops.

x86/include/apicvar.h:
 - Declare the apic_ops structure and create inline functions to
   access the hooks, so the change is transparent to existing users of
   the lapic_ functions.

x86/xen/hvm.c:
 - Switch to use the new apic_ops.
2014-06-16 08:43:03 +00:00
royger
6a8d0be395 xen: fix style in pv.c
Fix the lenght of some comments, and also add proper indentation to
xen_init_ops

Sponsored by: Citrix Systems R&D
Approved by: gibbs
2014-06-16 08:41:57 +00:00
scottl
38f58a4cec Eliminate the fake contig_dmamap and replace it with a new flag,
BUS_DMA_KMEM_ALLOC.  They serve the same purpose, but using the flag
means that the map can be NULL again, which in turn enables significant
optimizations for the common case of no bouncing.

Obtained from:	Netflix, Inc.
MFC after:	3 days
2014-05-27 21:31:11 +00:00
scottl
21c10cffc1 Now that there are separate back-end implementations of busdma, the bounce
implementation shouldn't steal flags from the common front-end.
Move those flags to the back-end.

Obtained from:  Netflix, Inc.
MFC after:      3 days
2014-05-27 14:18:57 +00:00
scottl
7cb2cf17ef Revert r266481. It was based on faulty analysis of the problem. A correct
fix is forthcoming.

Obtained from:	Netflix, Inc.
2014-05-27 14:06:23 +00:00
jhb
5662e763a6 Whitespace fix.
Submitted by:	kib
2014-05-22 18:13:17 +00:00
scottl
a1e98423bb Old PCIe implementations cannot allow a DMA transfer to cross a 4GB
boundary.  This was addressed several years ago by creating a parent
tag hierarchy for the root buses that set the boundary restriction
for appropriate buses and allowed child deviced to inherit it.
Somewhere along the way, this restriction was turned into a case for
marking the tag as a candidate for needing bounce buffers, instead
of just splitting the segment along the boundary line.  This flag
also causes all maps associated with this tag to be non-NULL, which
in turn causes bus_dmamap_sync() to take the slow path of function
pointer indirection to discover that there's no bouncing work to
do.  The end result is a lot of pages set aside in bounce pools
that will never be used, and a slow path for data buffers in nearly
every DMA-capable PCIe device.  For example, our workload at Netflix
was spending nearly 1% of all CPU time going through this slow path.

Fix this problem by being more selective about when to set the
COULD_BOUNCE flag.  Only set it when the boundary restriction
exists and the consumer cannot do more than a single DMA segment
at once.  This fixes the case of dynamic buffers (mbufs, bio's)
but doesn't address static buffers allocated from bus_dmamem_alloc().
That case will be addressed in the future.

For those interested, this was discovered thanks to Dtrace Flame
Graphs.

Discussed with: jhb, kib
Obtained from:	Netflix, Inc.
MFC after:	3 days
2014-05-20 22:43:17 +00:00
jhb
db4e203198 Add definitions for more structured extended features as well as
XSAVE Extended Features for AVX512 and MPX (Memory Protection Extensions).

Obtained from:	Intel's Instruction Set Extensions Programming Reference
                (March 2014)
2014-05-16 17:45:09 +00:00