If userspace has a newer bhyve than the kernel, it may be able to decode
and emulate some instructions vmm.ko is unaware of. In this scenario,
reset decoder state and try again.
Reviewed by: grehan
Differential Revision: https://reviews.freebsd.org/D24464
Permit instruction decoding logic to be compiled outside of the kernel for
rapid iteration and validation.
Reviewed by: grehan
Differential Revision: https://reviews.freebsd.org/D24439
This adds emulation for:
test r/m16, imm16
test r/m32, imm32
test r/m64, imm32 sign-extended to 64
OpenBSD guests compiled with clang 8.0.0 use TEST directly against a
Local APIC register instead of separate read via MOV followed by a
TEST against the register.
PR: 238794
Submitted by: jhb
Reported by: Jason Tubnor jason@tubnor.net
Tested by: Jason Tubnor jason@tubnor.net
Reviewed by: markj, Patrick Mooney patrick.mooney@joyent.com
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D20755
OVMF's flash variable storage is using add instructions when indexing
the variable store bootrom location.
Submitted by: D Scott Phillips <d.scott.phillips@intel.com>
Reviewed by: rgrimes
MFC after: 1 week
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D19975
Apparently CLFLUSH on mmio can cause VM exit, as reported in the PR.
I do not see that anything useful can be done except emulating page
faults on invalid addresses.
Due to the instruction encoding pecularity, also emulate SFENCE.
PR: 232081
Reported by: phk
Reviewed by: araujo, avg, jhb (all: previous version)
Sponsored by: The FreeBSD Foundation
Approved by: re (gjb)
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D17482
Unlike the existing GLA2GPA ioctl, GLA2GPA_NOFAULT does not modify
the guest. In particular, it does not inject any faults or modify
PTEs in the guest when performing an address space translation.
This is used by bhyve's debug server to read and write memory for
the remote debugger.
Reviewed by: grehan
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D14075
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
This is needed for the HDA emulation with FreeBSD guests.
Reviewed by: marcelo
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D12832
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
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
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
%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
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
instruction bytes in the VMCB on a nested page fault. This is useful because
it saves having to walk the guest page tables to fetch the instruction.
vie_init() now takes two additional parameters 'inst_bytes' and 'inst_len'
that map directly to 'vie->inst[]' and 'vie->num_valid'.
The instruction emulation handler skips calling 'vmm_fetch_instruction()'
if 'vie->num_valid' is non-zero.
The use of this capability can be turned off by setting the sysctl/tunable
'hw.vmm.svm.disable_npf_assist' to '1'.
Reviewed by: Anish Gupta (akgupt3@gmail.com)
Discussed with: grehan
proper constraint for 'x'. The "+r" constraint indicates that 'x' is an
input and output register operand.
While here generate code for different variants of getcc() using a macro
GETCC(sz) where 'sz' indicates the operand size.
Update the status bits in %rflags when emulating AND and OR opcodes.
Reviewed by: grehan
Add the ACPI MCFG table to advertise the extended config memory window.
Introduce a new flag MEM_F_IMMUTABLE for memory ranges that cannot be deleted
or moved in the guest's address space. The PCI extended config space is an
example of an immutable memory range.
Add emulation for the "movzw" instruction. This instruction is used by FreeBSD
to read a 16-bit extended config space register.
CR: https://phabric.freebsd.org/D505
Reviewed by: jhb, grehan
Requested by: tychon
It is not possible to PUSH a 32-bit operand on the stack in 64-bit mode. The
default operand size for PUSH is 64-bits and the operand size override prefix
changes that to 16-bits.
vm_copy_setup() can return '1' if it encounters a fault when walking the
guest page tables. This is a guest issue and is now handled properly by
resuming the guest to handle the fault.
instruction emulation [1].
Fix bug in emulation of opcode 0x8A where the destination is a legacy high
byte register and the guest vcpu is in 32-bit mode. Prior to this change
instead of modifying %ah, %bh, %ch or %dh the emulation would end up
modifying %spl, %bpl, %sil or %dil instead.
Add support for moffsets by treating it as a 2, 4 or 8 byte immediate value
during instruction decoding.
Fix bug in verify_gla() where the linear address computed after decoding
the instruction was not being truncated to the effective address size [2].
Tested by: Leon Dang [1]
Reported by: Peter Grehan [2]
Sponsored by: Nahanni Systems
API function 'vie_calculate_gla()'.
While the current implementation is simplistic it forms the basis of doing
segmentation checks if the guest is in 32-bit protected mode.
'struct vm_guest_paging'.
Check for canonical addressing in vmm_gla2gpa() and inject a protection
fault into the guest if a violation is detected.
If the page table walk is restarted in vmm_gla2gpa() then reset 'ptpphys' to
point to the root of the page tables.
indicate the faulting linear address.
If the guest PML4 entry has the PG_PS bit set then inject a page fault into
the guest with the PGEX_RSV bit set in the error_code.
Get rid of redundant checks for the PG_RW violations when walking the page
tables.
the UART FIFO.
The emulation is constrained in a number of ways: 64-bit only, doesn't check
for all exception conditions, limited to i/o ports emulated in userspace.
Some of these constraints will be relaxed in followup commits.
Requested by: grehan
Reviewed by: tychon (partially and a much earlier version)
Set the accessed and dirty bits in the page table entry. If it fails then
restart the page table walk from the beginning. This might happen if another
vcpu modifies the page tables simultaneously.
Reviewed by: alc, kib
to a guest physical address.
PG_PS (page size) field is valid only in a PDE or a PDPTE so it is now
checked only in non-terminal paging entries.
Ignore the upper 32-bits of the CR3 for PAE paging.
