Unlike some other architectures, RISC-V does not expose the current
privilege mode in any architecturally-defined register. That is intentional
to make it easier to implement virtualization in software, but a Unicorn
caller operates outside of the emulated hart and so it can and should be
able to observe and change the current privilege mode in order to properly
emulate certain behaviors of a real CPU.
The current privilege level is therefore now exposed as a new
pseudo-register using the name "priv", which matches the name of the
virtual register used by RISC-V's debug extension to allow the debugger
to read and change the privilege mode while the hart is halted. Unicorn's
use of it is conceptually similar to a debugger.
The bit encoding of this register is the same as specified in RISC-V Debug
Specification v1.0-rc3 Section 4.10.1. It's defined as a "virtual"
register exposing a subset of fields from the dcsr register, although here
it's implemented directly inside the Unicorn code because QEMU doesn't
currently have explicit support for the CSRs from the debug specification.
If it supports "dcsr" in a future release then this implementation could
change to wrap reading and writing that CSR and then projecting the "prv"
and "v" bitfields into the correct locations for the virtual register.
* optimize ram block handling
Save the last element of the ram_list. This allows to
faster find where to add new elements when they are not
bigger then page size.
* save ram_list freed
this keeps the optimization for find_ram_offset() intact after snapshot
restore.
* cow only clear the tlb of affected pages
* update flatview when possible
Building each flatview new when the memory has changed is quite
expensive when many MemoryRegions are used. This is an issue when using
snapshots.
* update benchmark for new api
* save flatview in context
this avoids rebuilding the flatview when restore a context.
* init context flatview with zero
* address_space_dispatch_clear remove subpage with higher priority
* docutemnt the options for UC_CTL_CONTEXT_MODE
Specialy stress that with UC_CTL_CONTEXT_MEMORY it is not possible to
use the context with a different unicorn object.
The ram_offset allocator searches the smalest gap in the ram_offset address space.
This is slow especialy in combination with many allocation (i.e. snapshots). When
it is known that there is no gap, this is now optimized.
Uses Copy on Write to make it posible to restore the memory state after a snapshot
was made. To restore all MemoryRegions created after the snapshot are removed.
These APIs take size parameters, which can be used to properly bounds-check the
inputs and outputs for various registers. Additionally, all backends now throw
UC_ERR_ARG if the input register numbers are invalid.
Completes #1831.
We still need this API because the virtual memory address space of
32 bits os is only 4GB and we default need 1G per instance
Credits to @ZehMatt for original idea
Co-authored-by: ζeh Matt <5415177+ZehMatt@users.noreply.github.com>
uc_ctl_flush_tlb implies that the tlb is flushed. This change adds
UC_CTL_TLB_FLUSH which clears the TLB and set the uc_ctl_flush_tlb
alias to UC_CTL_TLB_FLUSH. Also adds a uc_ctl_flush_tb alias for
UC_CTL_TB_FLUSH.
Unicorn has included some ugly hacks to provide a envirement where vaddr == paddr.
These hacks where to use the full 64 bit mappings on x86 without init the mmu
and some memory redirect for MIPS.
The UC_TLB_CPU mode defaults to vaddr == paddr, therfor these hacks aren't
required anymore.
quit_request is for internal use. This means the IP register was updated and
qemu needs to rebuild the translation blocks.
stop_request is set by the user (uc_emu_stop) to indecate that unicorn sould
stop emulating.
