Runtime services require special execution environment for the call.
Besides that, OS must inform firmware about runtime virtual memory map
which will be active during the calls, with the SetVirtualAddressMap()
runtime call, done while the 1:1 mapping is still used. There are two
complication: the SetVirtualAddressMap() effectively must be done from
loader, which needs to know kernel address map in advance. More,
despite not explicitely mentioned in the specification, both 1:1 and
the map passed to SetVirtualAddressMap() must be active during the
SetVirtualAddressMap() call. Second, there are buggy BIOSes which
require both mappings active during runtime calls as well, most likely
because they fail to identify all relocations to perform.
On amd64, we can get rid of both problems by providing 1:1 mapping for
the duration of runtime calls, by temprorary remapping user addresses.
As result, we avoid the need for loader to know about future kernel
address map, and avoid bugs in BIOSes. Typically BIOS only maps
something in low 4G. If not runtime bugs, we would take advantage of
the DMAP, as previous versions of this patch did.
Similar but more complicated trick can be used even for i386 and 32bit
runtime, if and when the EFI boot on i386 is supported. We would need
a trampoline page, since potentially whole 4G of VA would be switched
on calls, instead of only userspace portion on amd64.
Context switches are disabled for the duration of the call, FPU access
is granted, and interrupts are not disabled. The later is possible
because kernel is mapped during calls.
To test, the sysctl mib debug.efi_time is provided, setting it to 1
makes one call to EFI get_time() runtime service, on success the efitm
structure is printed to the control terminal. Load efirt.ko, or add
EFIRT option to the kernel config, to enable code.
Discussed with: emaste, imp
Tested by: emaste (mac, qemu)
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
physical address of the EFI System Table. Add _KERNEL guard around
its declaration in sys/efi.h.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Note that lgdt() name is already used for function which, besides
loading GDT, also reloads segment descriptors cache, thus new function
is named bare_lgdt().
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
amd64 pmap.
The new pmap_pinit_pml4() function initializes the level 4 page table
with entries for the kernel mappings. Both functions are needed for
upcoming EFI Runtime Services support.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
i386-only section, and fix a comment about the amd64 kernel trapframe
not having stackregs.
tf_rsp doesn't need decoding on amd64, but had an old clone of i386
code to do this in 1 place, and since the amd64 kernel trapframe does
have stackregs, the result was an off-by-16 error for %rsp in an error
message.
While here, avoid using the old variable 'code' and remove it
in trap(). ('code' was meant for holding things like %dr6,
but is too small to hold %dr6 on amd64 and was reduced to an
obfuscation of tf_err, with early truncation on amd64.)
Submitted by: Michael Butler (imb@...)
This is not very easy to do, since ddb didn't know when traps are
for single-stepping. It more or less assumed that traps are either
breakpoints or single-step, but even for x86 this became inadequate
with the release of the i386 in ~1986, and FreeBSD passes it other
trap types for NMIs and panics.
On x86, teach ddb when a trap is for single stepping using the %dr6
register. Unknown traps are now treated almost the same as breakpoints
instead of as the same as single-steps. Previously, the classification
of breakpoints was almost correct and everything else was unknown so
had to be treated as a single-step. Now the classification of single-
steps is precise, the classification of breakpoints is almost correct
(as before) and everything else is unknown and treated like a
breakpoint.
This fixes:
- breakpoints not set by ddb, including the main one in kdb_enter(),
were treated as single-steps and not stopped on when stepping
(except for the usual, simple case of a step with residual count 1).
As special cases, kdb_enter() didn't stop for fatal traps or panics
- similarly for "hardware breakpoints".
Use a new MD macro IS_SSTEP_TRAP(type, code) to code to classify
single-steps. This is excessively complicated for bug-for-bug and
backwards compatibilty. Design errors apparently started in Mach
in ~1990 or perhaps in the FreeBSD interface in ~1993. Common trap
types like single steps should have a unique MI code (like the TRAP*
codes for user SIGTRAP) so that debuggers don't need macros like
IS_SSTEP_TRAP() to decode them. But 'type' is actually an ambiguous
MD trap number, and code was always 0 (now it is (int)%dr6 on x86).
So it was impossible to determine the trap type from the args.
Global variables had to be used.
There is already a classification macro db_pc_is_single_step(), but
this just gets in the way. It is only used to recover from bugs in
IS_BREAKPOINT_TRAP(). On some arches, IS_BREAKPOINT_TRAP() just
duplicates the ambiguity in 'type' and misclassifies single-steps as
breakpoints. It defaults to 'false', which is the opposite of what is
needed for bug-for-bug compatibility.
When this is cleaned up, MI classification bits should be passed in
'code'. This could be done now for positive-logic bits, since 'code'
was always 0, but some negative logic is needed for compatibility so
a simple MI classificition is not usable yet.
After reading %dr6, clear the single-step bit in it so that the type
of the next debugger trap can be decoded. This is a little
ddb-specific. ddb doesn't understand the need to clear this bit and
doing it before calling kdb is easiest. gdb would need to reverse
this to support hardware breakpoints, but it just doesn't support
them now since gdbstub doesn't support %dr*.
Fix a bug involving %dr6: when emulating a single-step trap for vm86,
set the bit for it in %dr6. Userland debuggers need this. ddb now
needs this for vm86 bios calls. The bit gets copied to 'code' then
cleared again.
Fix related style bugs:
- when clearing bits for hardware breakpoints in %dr6, spell the mask
as ~0xf on both amd64 and i386 to get the correct number of bits
using sign extension and not need a comment about using the wrong
mask on amd64 (amd64 traps for invalid results but clearing the
reserved top bits didn't trap since they are 0).
- rewrite my old wrong comments about using %dr6 for ddb watchpoints.
The 'cpu' and 'cpu_class' variables were always set to the same value
on amd64 and are legacy holdovers from i386. Remove them entirely on
amd64.
Reviewed by: imp, kib (older version)
Differential Revision: https://reviews.freebsd.org/D7888
SEL_UPL and sometimes PSL_VM. This is just a style change on amd64,
but on i386 it fixes 1 unimportant place where the PSL_VM check was
missing and starts fixing 1 important place where the PSL_VM check
had a logic error.
Fix logic errors in treating vm86 bioscall mode as kernel mode. The
main place checked all the necessary flags, but put the necessary
parentheses for the PSL_VM and PCB_VM86CALL checks in the wrong
place. The broken case is only reached if a vm86 bioscall uses a
%cs which is nonzero mod 4, but that is unusual -- most bios calls
start with %cs = 0xc000 or 0xf000 and rarely change it. Another
place was missing the check for PCB_VM86CALL, but was only reachable
if there are bugs virtualizing PSL_I.
Add a macro TF_HAS_STACKREGS() and use this instead of converting
open-coded checks of SEL_UPL, etc. to TRAPF_USERMODE() when we only
care about whether the frame has stack registers. This fixes 3
places in my recent fix for register variables in vm86 mode where I
messed up the PSL_VM check and cleans up other places.
The flag specifies that the block which uses FPU must be executed in
critical section, i.e. take no context switches, and does not need an
FPU save area during the execution.
It is intended to be applied around fast and short code pathes where
save area allocation is impossible or undesirable, due to context or
due to the relative cost of calculation vs. allocation.
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Move PMAP_TS_REFERENCED_MAX out of the various pmap implementations and
into vm/pmap.h, and describe what its purpose is. Eliminate the archaic
"XXX" comment about its value. I don't believe that its exact value, e.g.,
5 versus 6, matters.
Update the arm64 and riscv pmap implementations of pmap_ts_referenced()
to opportunistically update the page's dirty field.
On amd64, use the PDE value already cached in a local variable rather than
dereferencing a pointer again and again.
Reviewed by: kib, markj
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D7836
Add routines to trigger a function level reset (FLR) of a PCI-express
device via the PCI-express device control register. This also includes
support routines to wait for pending transactions to complete as well
as calculating the maximum completion timeout permitted by a device.
Change the ppt(4) driver to reset pass through devices before attaching
to a VM during startup and before detaching from a VM during shutdown.
Reviewed by: imp, wblock (earlier version)
MFC after: 1 month
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D7751
When the I/O MMU is active in bhyve, all PCI devices need valid entries
in the DMAR context tables. The I/O MMU code does a single enumeration
of the available PCI devices during initialization to add all existing
devices to a domain representing the host. The ppt(4) driver then moves
pass through devices in and out of domains for virtual machines as needed.
However, when new PCI devices were added at runtime either via SR-IOV or
HotPlug, the I/O MMU tables were not updated.
This change adds a new set of EVENTHANDLERS that are invoked when PCI
devices are added and deleted. The I/O MMU driver in bhyve installs
handlers for these events which it uses to add and remove devices to
the "host" domain.
Reviewed by: imp
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D7667
This allows a pass through device to be reset to a normal device driver
on the host and reused on the host. ppt devices are now always active in
some I/O MMU domain when the I/O MMU is active, either the host domain
or the domain of a VM they are attached to.
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D7666
Idle page zeroing has been disabled by default on all architectures since
r170816 and has some bugs that make it seemingly unusable. Specifically,
the idle-priority pagezero thread exacerbates contention for the free page
lock, and yields the CPU without releasing it in non-preemptive kernels. The
pagezero thread also does not behave correctly when superpage reservations
are enabled: its target is a function of v_free_count, which includes
reserved-but-free pages, but it is only able to zero pages belonging to the
physical memory allocator.
Reviewed by: alc, imp, kib
Differential Revision: https://reviews.freebsd.org/D7714
dependent pmap_ts_referenced() so that it updates the page's dirty field
if a modified bit is found while counting reference bits. This
opportunistic update can be performed at low cost and can eliminate the
need for some future calls to pmap_is_modified() by the machine-
independent layer.
Reviewed by: kib, markj
MFC after: 3 weeks
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D7722
for zeroing pages in idle where nontemporal writes are clearly best.
This is almost a no-op since zeroing in idle works does nothing good
and is off by default. Fix END() statement forgotten in previous
commit.
Align the loop in sse2_pagezero(). Since it writes to main memory,
the loop doesn't have to be very carefully written to keep up.
Unrolling it was considered useless or harmful and was not done on
i386, but that was too careless.
Timing for i386: the loop was not unrolled at all, and moved only 4
bytes/iteration. So on a 2GHz CPU, it needed to run at 2 cycles/
iteration to keep up with a memory speed of just 4GB/sec. But when
it crossed a 16-byte boundary, on old CPUs it ran at 3 cycles/
iteration so it gave a maximum speed of 2.67GB/sec and couldn't even
keep up with PC3200 memory. Fix the alignment so that it keep up with
4GB/sec memory, and unroll once to get nearer to 8GB/sec. Further
unrolling might be useless or harmful since it would prevent the loop
fitting in 16-bytes. My test system with an old CPU and old DDR1 only
needed 5+ GB/sec. My test system with a new CPU and DDR3 doesn't need
any changes to keep up ~16GB/sec.
Timing for amd64: with 8-byte accesses and newer faster CPUs it is
easy to reach 16GB/sec but not so easy to go much faster. The
alignment doesn't matter much if the CPU is not very old. The loop
was already unrolled 4 times, but needs 32 bytes and uses a fancy
method that doesn't work for 2-way unrolling in 16 bytes. Just
align it to 32-bytes.
same name as for i386). It is not reconnected yet.
Which method is better is too machine-dependent and system-dependent
to replace the old method unconditionally.
Rather than enabling the I/O MMU when the vmm module is loaded,
defer initialization until the first attempt to pass a PCI device
through to a guest. If the I/O MMU fails to initialize or is not
present, than fail the attempt to pass a PCI device through to a
guest.
The hw.vmm.force_iommu tunable has been removed since the I/O MMU is
no longer enabled during boot. However, the I/O MMU support can be
disabled by setting the hw.vmm.iommu.enable tunable to 0 to prevent
use of the I/O MMU on any systems where it is buggy.
Reviewed by: grehan
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D7448
A nice thing about requiring a vDSO is that it makes it incredibly easy
to provide full support for running 32-bit processes on 64-bit systems.
Instead of letting the kernel be responsible for composing/decomposing
64-bit arguments across multiple registers/stack slots, all of this can
now be done in the vDSO. This means that there is no need to provide
duplicate copies of certain system calls, like the sys_lseek() and
freebsd32_lseek() we have for COMPAT_FREEBSD32.
This change imports a new vDSO from the CloudABI repository that has
automatically generated code in it that copies system call arguments
into a buffer, padding them to eight bytes and zero-extending any
pointers/size_t arguments. After returning from the kernel, it does the
inverse: extracting return values, in the process truncating
pointers/size_t values to 32 bits.
Obtained from: https://github.com/NuxiNL/cloudabi
In all of these source files, the userspace pointer size corresponds
with the kernelspace pointer size, meaning that casting directly works.
As I'm planning on making 32-bit execution on 64-bit systems work as
well, use TO_PTR() here as well, so that the changes between source
files remain minimal.
Move msix_disable_migration under #ifdef SMP since it doesn't make sense
for !SMP kernels.
PR: 212014
Reported by: Glyn Grinstead <glyn@grinstead.org>
MFC after: 3 days
The si(4) driver supported multiport serial adapters for ISA, EISA, and
PCI buses. This driver does not use bus_space, instead it depends on
direct use of the pointer returned by rman_get_virtual(). It is also
still locked by Giant and calls for patch testing to convert it to use
bus_space were unanswered.
Relnotes: yes
CloudABI executables already provide support for passing in vDSOs. This
functionality is used by the emulator for OS X to inject system call
handlers. On FreeBSD, we could use it to optimize calls to
gettimeofday(), etc.
Though I don't have any plans to optimize any system calls right now,
let's go ahead and already pass in a vDSO. This will allow us to
simplify the executables, as the traditional "syscall" shims can be
removed entirely. It also means that we gain more flexibility with
regards to adding and removing system calls.
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D7438
exception is caught in kernel mode. There are third-party modules
which trigger the issue, and since the problem causes usermode state
corruption at least, panic in production kernels as well.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
difference between files.
For pc98, put x86/mp_x86.c into the same place as used by i386 file list.
Fix typo in comment.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
The current implementation uses non-temporal writes. This turns out to
be detrimental to performance if the page is used shortly after, which
is the typical case with page faults.
Switch to rep stos.
Reviewed by: kib
MFC after: 1 week
Any sensible workflow will include a revision control system from which
to restore the old files if required. In normal usage, developers just
have to clean up the mess.
Reviewed by: jhb
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D7353
Set vm_guest to a new enum value (VM_GUEST_KVM) when kvm is detected and use
vm_guest in conditionals testing for KVM.
Also, fix a conditional checking if we're running in a VM which caught only
the generic VM case, but not more specific VMs (KVM, VMWare, etc.). (Spotted
by: vangyzen).
Differential revision: https://reviews.freebsd.org/D7172
Sponsored by: Dell Inc.
Approved by: kib (mentor), vangyzen (mentor)
Reviewed by: alc
MFC after: 4 weeks
If the hypervisor version is smaller than 4.6.0. Xen commits 74fd00 and
70a3cb are required on the hypervisor side for this to be fixed, and those
are only included in 4.6.0, so stay on the safe side and disable MSI-X
interrupt migration on anything older than 4.6.0.
It should not cause major performance degradation unless a lot of MSI-X
interrupts are allocated.
Sponsored by: Citrix Systems R&D
MFC after: 3 days
Reviewed by: jhb
Differential revision: https://reviews.freebsd.org/D7148
FreeBSD support NX bit on X86_64 processors out of the box, for i386 emulation
use READ_IMPLIES_EXEC flag, introduced in r302515.
While here move common part of mmap() and mprotect() code to the files in compat/linux
to reduce code dupcliation between Linuxulator's.
Reported by: Johannes Jost Meixner, Shawn Webb
MFC after: 1 week
XMFC with: r302515, r302516
In Linux if this flag is set, PROT_READ implies PROT_EXEC for mmap().
Linux/i386 set this flag automatically if the binary requires executable stack.
READ_IMPLIES_EXEC flag will be used in the next Linux mmap() commit.
