make no-kvm failing with "FATAL ERROR:system clock is inaccessible"

[wjhun]

On a fresh master tree:

$ qemu-system-x86_64 -version
QEMU emulator version 2.8.1(Debian 1:2.8+dfsg-6+deb9u4)
Copyright (c) 2003-2016 Fabrice Bellard and the QEMU Project developers
$ make run-nokvm
make -f image.mk image
make[1]: warning: jobserver unavailable: using -j1. Add '+' to parent make rule.
make[1]: Entering directory '/share/src/uniboot-test2'
cd boot ; make
make[2]: Entering directory '/share/src/uniboot-test2/boot'
make[2]: Nothing to be done for 'all'.
make[2]: Leaving directory '/share/src/uniboot-test2/boot'
cd mkfs ; make
make[2]: Entering directory '/share/src/uniboot-test2/mkfs'
make[2]: Nothing to be done for 'all'.
make[2]: Leaving directory '/share/src/uniboot-test2/mkfs'
cd stage3 ; make
make[2]: Entering directory '/share/src/uniboot-test2/stage3'
make[2]: Nothing to be done for 'all'.
make[2]: Leaving directory '/share/src/uniboot-test2/stage3'
cd examples ; make
make[2]: Entering directory '/share/src/uniboot-test2/examples'
make[2]: Nothing to be done for 'all'.
make[2]: Leaving directory '/share/src/uniboot-test2/examples'
make[1]: Leaving directory '/share/src/uniboot-test2'
cp image image2
qemu-system-x86_64 -boot c -drive file=image,format=raw,if=ide -nographic -m 2G -device isa-debug-exit -drive file=image2,format=raw,if=virtio
create fs
kernel complete
pages heap: 0000000000225000, length 00000000002f8000
physical memory:
base 0000000000800000, length 000000007f600000
FATAL ERROR:system clock is inaccessible
Makefile:46: recipe for target 'run-nokvm' failed
make: [run-nokvm] Error 1 (ignored)

[convolvatron]

i'm afraid this was intensional. without kvm we have no translation between rdtsc and
actual seconds. andrii did the first part of #24 which was to try to determine if
kvm was providing the right scaling factor for us.

the second part was to use a different time source so that we could function without hpet, which he's looking at

oddly, running without kvm seems to work. any tcp timers must be totally out of whack. i guess if there are no losses...

[wjhun]

Oh, I see. But for me it's not working without kvm.

Maybe this should stay in a topic branch until it works enough to not break for the common case? Not that I can't start using kvm, but running without it shouldn't be broken in master.

[talshadow]

@wjhun
I can suggest mark as comment this line for your test.
/uniboot/x86_64/clock.c:59

[convolvatron]

sorry, I was totally unclear. kvm provides the clock scaling factors, so running with lvm is safe.

andrii committed a change in response to #24 which halts if the scaling factor isn't set.

without the scaling factor the clock/timers make no sense, so this seemed reasonable.

could just set the halt back to a console

in order to get a decent clock in non-kvm, we need to write a driver.

[talshadow]

I think this issue we can close?

[wjhun]

Yes, thank you.