Add support for RISC-V #121
Draft
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Ivan-Velickovic
force-pushed
the
riscv
branch
3 times, most recently
from
0d6bfd7 to
cafeace
Compare
Ivan-Velickovic
force-pushed
the
riscv
branch
2 times, most recently
from
27b20d3 to
0a1299e
Compare
Signed-off-by: Ivan Velickovic <[email protected]>
Now we are stuck on this line: 'cpuidle: using governor menu'
Current progress: ``` [ 0.095968] Unpacking initramfs... [ 0.212981] Freeing initrd memory: 16384K [ 0.214101] workingset: timestamp_bits=46 max_order=16 bucket_order=0 [ 0.216709] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 246) [ 0.216914] io scheduler mq-deadline registered [ 0.217026] io scheduler kyber registered [ 0.217192] io scheduler bfq registered VMM|INFO: handling fault 'virtual memory exception' VMM|INFO: fault on addr 0xc002080 VMM|INFO: handling plic 0xc002080 VMM|INFO: satp: 0xa0000000000814f7 Failed assertion '(satp >> 60) == SV39_MODE' at /Users/ivanv/ts/libvmm/src/arch/riscv/fault.c:111 in function guest_virtual_physical ``` now need to deal with PLIC faults Things are a bit concerning because I had to disable two Linux kernel config options: * CONFIG_RISCV_ISA_ZICBOM * CONFIG_RISCV_PROBE_UNALIGNED_ACCESS ZICBOM was causing a vCPU fault, maybe there's something that seL4 needs to allow at VS level that it's not. What's weirder is that program counter in Linux was at the specific point of a no-op instruction which is weird. Secondly, RISCV_PROBE_UNALIGNED_ACCESS was causing some hanging because it's using `rdtime` to determine whether unaligned access is allowed by the hardware. This again is an issue with how we are emulating as the Linux image with both of these configs enabled runs fine bare-metal on QEMU (without seL4 involved.). More investigation required...
Problem is that FPU access in Linux or Linux user-space causes exceptions *in Linux*, which is weird for two reasons: 1. We have the FPU enabled for QEMU in seL4 so I would think that the guest would have FPU access as well. 2. Why is an illegal instruction exception that happened *within Linux* being handled by Linux instead of the VMM?
Timer IRQs are now handled, some fixes in seL4 itself were needed
Signed-off-by: Ivan-Velickovic <[email protected]>
Signed-off-by: Ivan-Velickovic <[email protected]>
Signed-off-by: Ivan-Velickovic <[email protected]>
Signed-off-by: Ivan-Velickovic <[email protected]>
…/hacks so it works
…sole Most likely issue with bootargs/rootfs configuration.
… memory Signed-off-by: Ivan-Velickovic <[email protected]>
…on guest memory" This reverts commit 47e1fe338493daf444238c9762de115e1544d554. Seems like on the HiFive P550 we get htinst of zero some times which means we have to do the encoding. This is temporary and instead what we want is that we only do the encoding when we get htinst as zero.
…ith regards to FPU switching.
Signed-off-by: Ivan-Velickovic <[email protected]>
Ivan-Velickovic
force-pushed
the
riscv
branch
from
41dbc8d to
b4396d8
Compare
Signed-off-by: Ivan-Velickovic <[email protected]>
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This PR adds initial support for RISC-V guests to libvmm.
Right now, only 64-bit guests are supported/tested.
This PR is a draft as there is still much more work to do and more to test/fix such as multiple vCPUs are more complex example systems, but right now a Linux guest can boot and get into user-space.
This PR will likely not be merged for a while as it depends on changes to seL4, which will require an RFC and code review that typically takes months.
To try out this PR, you will need changes a specific branch of Microkit and seL4: