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Bochs/bochs/plex86/TODO

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Got rid of use of mmap() altogether. User space (bochs) allocates all the memory it needs, and the plex86 kernel module uses get_user_pages() from the Linux kernel to get at them and pin the few that are needed statically (and later up to a watermark of pages that are needed dynamically). Guest physical memory pages are now dynamically pinned/unpinned. For now, I use a hard limit of 4Megs of pinned pages and a really primitive algorithm to decide which one to unpin when the limit is reached and one needs to be bumped. Seems to work. Though I haven't run into the limit yet since I'm using just a small test program.
2003-01-09 04:02:31 +00:00
Main monitor loop should compare cycles burned thus far vs
cycles requested, so it doesn't keep bopping back and forth
between host-kernel and monitor spaces without returning to
user space.
Some cleanup.
2003-01-02 02:11:40 +00:00
Fix monPrint and friends.
More code cleanups.
2003-01-02 17:05:47 +00:00
monpanic breaks up into 2 monprints which hit user space twice.
Some cleanup.
2003-01-02 02:11:40 +00:00
Could put the GDT/LDT in linear memory where the guest
More code cleanups.
2003-01-02 17:05:47 +00:00
expects them.
Some cleanup.
2003-01-02 02:11:40 +00:00
Added plex86 directory to bochs. This directory contains the new experimental stripped-down version of plex86, which is now a user-code-only VM. I ripped out all the fancy stuff in plex86, such that under that right conditions, user-code (protection level 3) can run at near native speeds inside the plex86 VM. The general idea is that bochs emulates all the initial real-mode code, and guest kernel code (protection level 0). When it senses the right conditions (like the context switches to user-code), a shim is called to execute the guest inside the plex86 VM. All guest-generated faults/exceptions are then forwarded back to bochs to be handled in the emulator. Actually, I'm not yet adding the mods to the bochs code (other than the shim code which is in a separate file), until I hear that we're back in a more development mode with bochs after the 2.0 release. The plex86 subdirectory is really a separate project. It's just more convenient to co-develop it with bochs for now. Both projects are currently LGPL, but each should be taken to be a separate project, and have their own license file. Plex86 (it's only a kernel driver now) could ultimately be used with other projects, as it's modular. I talked with Bryce, and we both agreed it's OK to keep plex86 as a subdir in bochs for now.
2003-01-01 17:32:06 +00:00
Synchronize page writes with iCache in bochs.
Deal with cycle counts of guest execution in VM, and in
bochs/plex86 shim.
Deal with page_usage. How do we update this between timeslices?
Do we always clear it? Maybe we should keep a log of things to
clear (page_usage, GDT entries, PDE entries, ...) and clear those
before returning to user space.
More code cleanups.
2003-01-02 17:05:47 +00:00
GDT entries for guest need to be cleared upon return from guest
execution, or just cleared before invocation of the guest.
Added plex86 directory to bochs. This directory contains the new experimental stripped-down version of plex86, which is now a user-code-only VM. I ripped out all the fancy stuff in plex86, such that under that right conditions, user-code (protection level 3) can run at near native speeds inside the plex86 VM. The general idea is that bochs emulates all the initial real-mode code, and guest kernel code (protection level 0). When it senses the right conditions (like the context switches to user-code), a shim is called to execute the guest inside the plex86 VM. All guest-generated faults/exceptions are then forwarded back to bochs to be handled in the emulator. Actually, I'm not yet adding the mods to the bochs code (other than the shim code which is in a separate file), until I hear that we're back in a more development mode with bochs after the 2.0 release. The plex86 subdirectory is really a separate project. It's just more convenient to co-develop it with bochs for now. Both projects are currently LGPL, but each should be taken to be a separate project, and have their own license file. Plex86 (it's only a kernel driver now) could ultimately be used with other projects, as it's modular. I talked with Bryce, and we both agreed it's OK to keep plex86 as a subdir in bochs for now.
2003-01-01 17:32:06 +00:00
Task segment must be a 32-bit'er.
Save/restore floating point state of host/VM.
deduct off some cycles for the IRET/int sequence.
More code cleanups.
2003-01-02 17:05:47 +00:00
Conditions for bochs compile using plex86:
- Not compiled for debug
- x86 host
Unified the routines to retrieve physical page addresses underlying a region of virtual memory. Now the same one works for getting the pages of the kernel driver and memory objects allocated via vmalloc(). Converted to using Linux interfaces to walk the page tables to get at the physical memory addresses above. The old code was digging up this info starting with looking at CR3. Linux has functions/macros to do this, which can handle 2/3-level cases. Wrapped the page table walk with proper locks. A spin lock for new Linuxes, a big kernel lock for old ones.
2003-01-04 01:21:18 +00:00
- Not PCI supported (for now).
Added plex86 directory to bochs. This directory contains the new experimental stripped-down version of plex86, which is now a user-code-only VM. I ripped out all the fancy stuff in plex86, such that under that right conditions, user-code (protection level 3) can run at near native speeds inside the plex86 VM. The general idea is that bochs emulates all the initial real-mode code, and guest kernel code (protection level 0). When it senses the right conditions (like the context switches to user-code), a shim is called to execute the guest inside the plex86 VM. All guest-generated faults/exceptions are then forwarded back to bochs to be handled in the emulator. Actually, I'm not yet adding the mods to the bochs code (other than the shim code which is in a separate file), until I hear that we're back in a more development mode with bochs after the 2.0 release. The plex86 subdirectory is really a separate project. It's just more convenient to co-develop it with bochs for now. Both projects are currently LGPL, but each should be taken to be a separate project, and have their own license file. Plex86 (it's only a kernel driver now) could ultimately be used with other projects, as it's modular. I talked with Bryce, and we both agreed it's OK to keep plex86 as a subdir in bochs for now.
2003-01-01 17:32:06 +00:00
More code cleanups.
2003-01-02 17:05:47 +00:00
paging-mon.c: We can eliminate any code other than CPL==3.
Added plex86 directory to bochs. This directory contains the new experimental stripped-down version of plex86, which is now a user-code-only VM. I ripped out all the fancy stuff in plex86, such that under that right conditions, user-code (protection level 3) can run at near native speeds inside the plex86 VM. The general idea is that bochs emulates all the initial real-mode code, and guest kernel code (protection level 0). When it senses the right conditions (like the context switches to user-code), a shim is called to execute the guest inside the plex86 VM. All guest-generated faults/exceptions are then forwarded back to bochs to be handled in the emulator. Actually, I'm not yet adding the mods to the bochs code (other than the shim code which is in a separate file), until I hear that we're back in a more development mode with bochs after the 2.0 release. The plex86 subdirectory is really a separate project. It's just more convenient to co-develop it with bochs for now. Both projects are currently LGPL, but each should be taken to be a separate project, and have their own license file. Plex86 (it's only a kernel driver now) could ultimately be used with other projects, as it's modular. I talked with Bryce, and we both agreed it's OK to keep plex86 as a subdir in bochs for now.
2003-01-01 17:32:06 +00:00
More code cleanups.
2003-01-02 17:05:47 +00:00
Fix extra PDBR reload in nexus.S
Added plex86 directory to bochs. This directory contains the new experimental stripped-down version of plex86, which is now a user-code-only VM. I ripped out all the fancy stuff in plex86, such that under that right conditions, user-code (protection level 3) can run at near native speeds inside the plex86 VM. The general idea is that bochs emulates all the initial real-mode code, and guest kernel code (protection level 0). When it senses the right conditions (like the context switches to user-code), a shim is called to execute the guest inside the plex86 VM. All guest-generated faults/exceptions are then forwarded back to bochs to be handled in the emulator. Actually, I'm not yet adding the mods to the bochs code (other than the shim code which is in a separate file), until I hear that we're back in a more development mode with bochs after the 2.0 release. The plex86 subdirectory is really a separate project. It's just more convenient to co-develop it with bochs for now. Both projects are currently LGPL, but each should be taken to be a separate project, and have their own license file. Plex86 (it's only a kernel driver now) could ultimately be used with other projects, as it's modular. I talked with Bryce, and we both agreed it's OK to keep plex86 as a subdir in bochs for now.
2003-01-01 17:32:06 +00:00
More code cleanups.
2003-01-02 17:05:47 +00:00
Manipulation/reading of host page tables needs to be SMP/preempt
compatible. Need to do spin-lock (big kernel lock for old Linux)
on vma.
Added plex86 directory to bochs. This directory contains the new experimental stripped-down version of plex86, which is now a user-code-only VM. I ripped out all the fancy stuff in plex86, such that under that right conditions, user-code (protection level 3) can run at near native speeds inside the plex86 VM. The general idea is that bochs emulates all the initial real-mode code, and guest kernel code (protection level 0). When it senses the right conditions (like the context switches to user-code), a shim is called to execute the guest inside the plex86 VM. All guest-generated faults/exceptions are then forwarded back to bochs to be handled in the emulator. Actually, I'm not yet adding the mods to the bochs code (other than the shim code which is in a separate file), until I hear that we're back in a more development mode with bochs after the 2.0 release. The plex86 subdirectory is really a separate project. It's just more convenient to co-develop it with bochs for now. Both projects are currently LGPL, but each should be taken to be a separate project, and have their own license file. Plex86 (it's only a kernel driver now) could ultimately be used with other projects, as it's modular. I talked with Bryce, and we both agreed it's OK to keep plex86 as a subdir in bochs for now.
2003-01-01 17:32:06 +00:00
==================== From previous plex86 TODO file ====================
This is a list of the major tasks/achievements/milestones yet to-do.
We should keep this list prioritized, creating sort of a road map.
Hopefully, this will reduce duplicate suggestions on the developers
channels, and let people know where we are in the development process.
Entries listed first have highest priority.
<NEAR-TERM>
- Fix plex86 on Linux 2.4.x/SMP or with 1P and LAPIC enabled.
- Save FPU state on host <--> monitor context switch.
- Special guest-specific drivers and special emulated pseudo-devices
for faster graphics/network/disk access.
- Allow some of the inactive guest pages be host swappable.
Currently, all pages are locked down.
- Many performance enhancements (see PERFORMANCE)
- Allow memory to be mapped anywhere in the physical address
space.
- Allow certain guest pages to be swap eligible by the host.
This means they will have to be unavailable by the guest
during that time. Need a dynamic algorith for this.
- Test on 2.4 with SMP/APIC enabled on single processor machine.
- Deal with guest use of TF.
- Deal with LDT
unallocVmPages/unreserve_guest_pages called twice,
release & teardown.
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