Some external tools just do a 'ls /dev/vmm' to figure out the bhyve virtual
machines on the host. These tools break if the devmem device nodes also
appear in /dev/vmm.
Requested by: grehan
Previously this was done by the caller of 'svm_launch()' after it returned.
This works fine as long as no code is executed in the interim that depends
on pcpu data.
The dtrace probe 'fbt:vmm:svm_launch:return' broke this assumption because
it calls 'dtrace_probe()' which in turn relies on pcpu data.
Reported by: avg
MFC after: 1 week
devmem is used to represent MMIO devices like the boot ROM or a VESA framebuffer
where doing a trap-and-emulate for every access is impractical. devmem is a
hybrid of system memory (sysmem) and emulated device models.
devmem is mapped in the guest address space via nested page tables similar
to sysmem. However the address range where devmem is mapped may be changed
by the guest at runtime (e.g. by reprogramming a PCI BAR). Also devmem is
usually mapped RO or RW as compared to RWX mappings for sysmem.
Each devmem segment is named (e.g. "bootrom") and this name is used to
create a device node for the devmem segment (e.g. /dev/vmm/testvm.bootrom).
The device node supports mmap(2) and this decouples the host mapping of
devmem from its mapping in the guest address space (which can change).
Reviewed by: tychon
Discussed with: grehan
Differential Revision: https://reviews.freebsd.org/D2762
MFC after: 4 weeks
execution control and writing the difference between the host TSC and
the guest TSC into the TSC offset in the VMCS upon encountering a
write.
Reviewed by: neel
after decoding the instruction matches the one provided by hardware.
Prior to r283293 'vie->num_valid' used to contain the actual length of
the instruction whereas now it contains the maximum instruction length
possible. This introduced a bug when calculating a RIP-relative base address.
Fix this by using 'vie->num_processed' rather than 'vie->num_valid' as the
length of the emulated instruction.
Reported and tested by: tychon
MFC after: 1 week
"sleeping" state. This is done by forcing the vcpu to transition to "idle"
by returning to userspace with an exit code of VM_EXITCODE_REQIDLE.
MFC after: 2 weeks
have an accurate length on an EPT violation. This is not needed by the
instruction decoding code because it also has to work with AMD/SVM that
does not provide a valid instruction length on a Nested Page Fault.
In collaboration with: Leon Dang (ldang@nahannisys.com)
Discussed with: grehan
MFC after: 1 week
years for head. However, it is continuously misused as the mpsafe argument
for callout_init(9). Deprecate the flag and clean up callout_init() calls
to make them more consistent.
Differential Revision: https://reviews.freebsd.org/D2613
Reviewed by: jhb
MFC after: 2 weeks
Prior to this change both functions returned 0 for success, -1 for failure
and +1 to indicate that an exception was injected into the guest.
The numerical value of ERESTART also happens to be -1 so when these functions
returned -1 it had to be translated to a positive errno value to prevent the
VM_RUN ioctl from being inadvertently restarted. This made it easy to introduce
bugs when writing emulation code.
Fix this by adding an 'int *guest_fault' parameter and setting it to '1' if
an exception was delivered to the guest. The return value is 0 or EFAULT so
no additional translation is needed.
Reviewed by: tychon
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D2428
- Must-Be-Zero bits cannot be set.
- EFER_LME and EFER_LMA should respect the long mode consistency checks.
- EFER_NXE, EFER_FFXSR, EFER_TCE can be set if allowed by CPUID capabilities.
- Flag an error if guest tries to set EFER_LMSLE since bhyve doesn't enforce
segment limits in 64-bit mode.
MFC after: 2 weeks
Do the same when transitioning a vector from the IRR to the ISR and also
when extinguishing it from the ISR in response to an EOI.
Reported by: Leon Dang (ldang@nahannisys.com)
MFC after: 2 weeks
losing time.
The problem with the earlier implementation was that the uptime value
used by 'vrtc_curtime()' could be different than the uptime value when
'vrtc_time_update()' actually updated 'base_uptime'.
Fix this by calculating and updating the (rtctime, uptime) tuple together.
MFC after: 2 weeks
to the Intel SDM vectors 16 through 255 are allowed to be delivered via the
local APIC.
Reported by: Leon Dang (ldang@nahannisys.com)
MFC after: 2 weeks
%rdi, %rsi, etc are inadvertently bypassed along with the check to
see if the instruction needs to be repeated per the 'rep' prefix.
Add "MOVS" instruction support for the 'MMIO to MMIO' case.
Reviewed by: neel
code segment base address.
Also if an instruction doesn't support a mod R/M (modRM) byte, don't
be concerned if the CPU is in real mode.
Reviewed by: neel
This makes FreeBSD guest to not avoid using LAPIC timer, preferring HPET
due to worries about non-existing for virtual CPUs deep sleep states.
Benchmarks of usleep(1) on guest and host show such extra latencies:
- 51us for virtual HPET,
- 22us for virtual LAPIC timer,
- 22us for host HPET and
- 3us for host LAPIC timer.
MFC after: 2 weeks
- fix warning about comparison of 'uint8_t v_tpr >= 0' always being true.
- fix error triggered by an empty clobber list in the inline assembly for
"clgi" and "stgi"
- fix error when compiling "vmload %rax", "vmrun %rax" and "vmsave %rax". The
gcc assembler does not like the explicit operand "%rax" while the clang
assembler requires specifying the operand "%rax". Fix this by encoding the
instructions using the ".byte" directive.
Reported by: julian
MFC after: 1 week
Allow the ppt driver to attach to devices that were hinted to be
passthrough devices by the PCI code creating them with a driver
name of "ppt".
Add a tunable that allows the IOMMU to be forced to be used. With
SR-IOV passthrough devices the VFs may be created after vmm.ko is
loaded. The current code will not initialize the IOMMU in that
case, meaning that the passthrough devices can't actually be used.
Differential Revision: https://reviews.freebsd.org/D73
Reviewed by: neel
MFC after: 1 month
Sponsored by: Sandvine Inc.
capability of VT-x. This lets bhyve run nested in older VMware versions that
don't support the PAT save/restore capability.
Note that the actual value programmed by the guest in MSR_PAT is irrelevant
because bhyve sets the 'Ignore PAT' bit in the nested PTE.
Reported by: marcel
Tested by: Leon Dang (ldang@nahannisys.com)
Sponsored by: Nahanni Systems
MFC after: 2 weeks
hw.x2apic_enable tunable allows disabling it from the loader prompt.
To closely repeat effects of the uncached memory ops when accessing
registers in the xAPIC mode, the x2APIC writes to MSRs are preceeded
by mfence, except for the EOI notifications. This is probably too
strict, only ICR writes to send IPI require serialization to ensure
that other CPUs see the previous actions when IPI is delivered. This
may be changed later.
In vmm justreturn IPI handler, call doreti_iret instead of doing iretd
inline, to handle corner conditions.
Note that the patch only switches LAPICs into x2APIC mode. It does not
enables FreeBSD to support > 255 CPUs, which requires parsing x2APIC
MADT entries and doing interrupts remapping, but is the required step
on the way.
Reviewed by: neel
Tested by: pho (real hardware), neel (on bhyve)
Discussed with: jhb, grehan
Sponsored by: The FreeBSD Foundation
MFC after: 2 months
These instructions are emitted by 'bus_space_read_region()' when accessing
MMIO regions.
Since MOVS can be used with a repeat prefix start decoding the REPZ and
REPNZ prefixes. Also start decoding the segment override prefix since MOVS
allows overriding the source operand segment register.
Tested by: tychon
MFC after: 1 week
Keep track of the next instruction to be executed by the vcpu as 'nextrip'.
As a result the VM_RUN ioctl no longer takes the %rip where a vcpu should
start execution.
Also, instruction restart happens implicitly via 'vm_inject_exception()' or
explicitly via 'vm_restart_instruction()'. The APIs behave identically in
both kernel and userspace contexts. The main beneficiary is the instruction
emulation code that executes in both contexts.
bhyve(8) VM exit handlers now treat 'vmexit->rip' and 'vmexit->inst_length'
as readonly:
- Restarting an instruction is now done by calling 'vm_restart_instruction()'
as opposed to setting 'vmexit->inst_length' to 0 (e.g. emulate_inout())
- Resuming vcpu at an arbitrary %rip is now done by setting VM_REG_GUEST_RIP
as opposed to changing 'vmexit->rip' (e.g. vmexit_task_switch())
Differential Revision: https://reviews.freebsd.org/D1526
Reviewed by: grehan
MFC after: 2 weeks
VM_INJECT_EXCEPTION ioctl. However it morphed into other uses like keeping
track pending exceptions for a vcpu. This in turn causes confusion because
some fields in 'struct vm_exception' like 'vcpuid' make sense only in the
ioctl context. It also makes it harder to add or remove structure fields.
Fix this by using 'struct vm_exception' only to communicate information
from userspace to vmm.ko when injecting an exception.
Also, add a field 'restart_instruction' to 'struct vm_exception'. This
field is set to '1' for exceptions where the faulting instruction is
restarted after the exception is handled.
MFC after: 1 week
emulated or when the vcpu incurs an exception. This matches the CPU behavior.
Remove special case code in HLT processing that was clearing the interrupt
shadow. This is now redundant because the interrupt shadow is always cleared
when the vcpu is resumed after an instruction is emulated.
Reported by: David Reed (david.reed@tidalscale.com)
MFC after: 2 weeks
vm_inject_exception(). This fixes the issue that 'exception.cpuid' is
uninitialized when calling 'vm_inject_exception()'.
However, in practice this change is a no-op because vm_inject_exception()
does not use 'exception.cpuid' for anything.
Reported by: Coverity Scan
CID: 1261297
MFC after: 3 days
The new RTC emulation supports all interrupt modes: periodic, update ended
and alarm. It is also capable of maintaining the date/time and NVRAM contents
across virtual machine reset. Also, the date/time fields can now be modified
by the guest.
Since bhyve now emulates both the PIT and the RTC there is no need for
"Legacy Replacement Routing" in the HPET so get rid of it.
The RTC device state can be inspected via bhyvectl as follows:
bhyvectl --vm=vm --get-rtc-time
bhyvectl --vm=vm --set-rtc-time=<unix_time_secs>
bhyvectl --vm=vm --rtc-nvram-offset=<offset> --get-rtc-nvram
bhyvectl --vm=vm --rtc-nvram-offset=<offset> --set-rtc-nvram=<value>
Reviewed by: tychon
Discussed with: grehan
Differential Revision: https://reviews.freebsd.org/D1385
MFC after: 2 weeks
