Re: Starting a VM reboots my machine

Avi Kivity
2007-11-05T14:25:00Z

Andrea Arcangeli wrote:
> On Sun, Nov 04, 2007 at 08:15:26AM -0800, Alexey Eremenko wrote:
>
>> Cam: KVM-AMD is unstable now, unless you're a developer, I would suggest you to downgrade to KVM-36, which was the latest AMD-friendly version. We're working on a fix.
>>
>> Dor: kvm-amd crashes host, without leaving any netconsole messages.
>>
>
> With x2 stepping G1 and with the below two fixes applied on top of kvm
> and kvm-userland at least the host is certainly solid for me (the
> opensuse 10.3 guest seems ok too). The x86 hack is mandatory with last
> git kvm kernel, without it it's an immediate crash.
>
> Signed-off-by: Andrea Arcangeli <andrea-l3A5Bk7waGM@public.gmane.org>
>
> diff --git a/kernel/Makefile b/kernel/Makefile
> index b78c81a..68f6929 100644
> --- a/kernel/Makefile
> +++ b/kernel/Makefile
> @@ -32,6 +32,7 @@ sync:
> $(call hack, mmu.c)
> $(call hack, vmx.c)
> $(call hack, svm.c)
> + $(call hack, x86.c)
>
> install:
> mkdir -p $(DESTDIR)/$(INSTALLDIR)
>
>
>

This one's obviously correct, will apply...

> Signed-off-by: Andrea Arcangeli <andrea-l3A5Bk7waGM@public.gmane.org>
>
> index 9584d0f..95a3489 100644
> --- a/drivers/kvm/svm.c
> +++ b/drivers/kvm/svm.c
> @@ -1459,11 +1459,6 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
>
> local_irq_enable();
>
> - vcpu->guest_mode = 1;
> - if (vcpu->requests)
> - if (test_and_clear_bit(KVM_TLB_FLUSH, &vcpu->requests))
> - svm_flush_tlb(vcpu);
> -
> asm volatile (
> #ifdef CONFIG_X86_64
> "push %%rbp; \n\t"
>
>

Against which kvm is that? It isn't 2.6.24-rc, or kvm.git, or 2.6.23?

Anyway, removing guest tlb flushing won't be good for the guest.

--
Any sufficiently difficult bug is indistinguishable from a feature.