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CVS commit: src/sys
Module Name: src
Committed By: maxv
Date: Wed Feb 13 16:03:16 UTC 2019
src/sys/dev/nvmm: nvmm.c nvmm_internal.h
src/sys/dev/nvmm/x86: nvmm_x86_vmx.c nvmm_x86_vmxfunc.S
Add Intel-VMX support in NVMM. This allows us to run hardware-accelerated
VMs on Intel CPUs. Overall this implementation is fast and reliable, I am
able to run NetBSD VMs with many VCPUs on a quad-core Intel i5.
NVMM-Intel applies several optimizations already present in NVMM-AMD, and
has a code structure similar to it. No change was needed in the NVMM MI
frontend, or in libnvmm.
Some differences exist against AMD:
- On Intel the ASID space is big, so we don't fall back to a shared ASID
when there are more VCPUs executing than available ASIDs in the host,
contrary to AMD. There are enough ASIDs for the maximum number of VCPUs
supported by NVMM.
- On Intel there are two TLBs we need to take care of, one for the host
(EPT) and one for the guest (VPID). Changes in EPT paging flush the
host TLB, changes to the guest mode flush the guest TLB.
- On Intel there is no easy way to set/fetch the VTPR, so we intercept
reads/writes to CR8 and maintain a software TPR, that we give to the
virtualizer as if it was the effective TPR in the guest.
- On Intel, because of SVS, the host CR4 and LSTAR are not static, so
we're forced to save them on each VMENTRY.
- There is extra Intel weirdness we need to take care of, for example the
reserved bits in CR0 and CR4 when accesses trap.
While this implementation is functional and can already run many OSes, we
likely have a problem on 32bit-PAE guests, because they require special
care on Intel CPUs, and currently we don't handle that correctly; such
guests may misbehave for now (without altering the host stability). I
expect to fix that soon.
To generate a diff of this commit:
cvs rdiff -u -r1.6 -r1.7 src/sys/dev/nvmm/nvmm.c
cvs rdiff -u -r1.4 -r1.5 src/sys/dev/nvmm/nvmm_internal.h
cvs rdiff -u -r0 -r1.1 src/sys/dev/nvmm/x86/nvmm_x86_vmx.c \
cvs rdiff -u -r1.1 -r1.2 src/sys/modules/nvmm/Makefile
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
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