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History log of /src/sys/dev/nvmm/x86/nvmm_x86_vmxfunc.S
RevisionDateAuthorComments
 1.6  05-Sep-2020  maxv nvmm: update copyright headers
 1.5  11-Aug-2020  maxv Micro-optimize: use pushq instead of pushw. To avoid LCP stalls and
unaligned stack accesses.
 1.4  19-Jul-2020  maxv The TLB flush IPIs do not respect the IPL, so enforcing IPL_HIGH has no
effect. Disable interrupts earlier instead. This prevents a possible race
against such IPIs.
 1.3  27-Apr-2019  maxv branches: 1.3.2; 1.3.4;
Optimize nvmm-intel, use inlined GCC assembly rather than function calls.
 1.2  24-Apr-2019  maxv Match the structure order, for better cache utilization.
 1.1  13-Feb-2019  maxv 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.
 1.3.4.1  29-Aug-2020  martin Pull up following revision(s) (requested by maxv in ticket #1068):

sys/dev/nvmm/x86/nvmm_x86_svm.c: revision 1.71
sys/dev/nvmm/nvmm.c: revision 1.34
sys/dev/nvmm/x86/nvmm_x86_svm.c: revision 1.72
sys/dev/nvmm/nvmm.c: revision 1.35
sys/dev/nvmm/nvmm.c: revision 1.36
sys/dev/nvmm/x86/nvmm_x86_svmfunc.S: revision 1.5
sys/dev/nvmm/nvmm.c: revision 1.37
sys/dev/nvmm/x86/nvmm_x86_vmxfunc.S: revision 1.5
sys/dev/nvmm/x86/nvmm_x86_vmx.c: revision 1.70
sys/dev/nvmm/x86/nvmm_x86_svm.c: revision 1.68
sys/dev/nvmm/x86/nvmm_x86.c: revision 1.15
sys/dev/nvmm/nvmm_ioctl.h: revision 1.10

Micro-optimize: use pushq instead of pushw. To avoid LCP stalls and
unaligned stack accesses.

nvmm-x86: also flush the guest TLB when CR4.{PCIDE,SMEP} changes

nvmm: localify a variable that doesn't need to be global

nvmm: use relaxed atomics to read nmachines

nvmm-x86-svm: dedup code

nvmm-x86: hide more CPUID flags, mostly related to perf monitors

nvmm: misc improvements
- use mach->ncpus to get the number of vcpus, now that we have it
- don't forget to decrement mach->ncpus when a machine gets killed
- add more __predict_false()

nvmm-x86-svm: don't forget to intercept INVD
INVD executed in the guest can be dangerous for the host, due to CPU
caches being flushed without write-back.

nvmm: slightly clarify

nvmm: explicitly include atomic.h
 1.3.2.2  10-Jun-2019  christos Sync with HEAD
 1.3.2.1  27-Apr-2019  christos file nvmm_x86_vmxfunc.S was added on branch phil-wifi on 2019-06-10 22:07:14 +0000

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