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[Qemu-devel] Re: [PATCH 4/4] KVM: Rework of guest debug state writing
From: |
Marcelo Tosatti |
Subject: |
[Qemu-devel] Re: [PATCH 4/4] KVM: Rework of guest debug state writing |
Date: |
Mon, 8 Feb 2010 13:52:16 -0200 |
User-agent: |
Mutt/1.5.20 (2009-08-17) |
On Thu, Feb 04, 2010 at 08:21:08PM +0100, Jan Kiszka wrote:
> Jan Kiszka wrote:
> > Marcelo Tosatti wrote:
> >> With kvm-autotest the failure is not sporadic (and the above commit
> >> applied): with KVM_SET_GUEST_DEBUG in arch_put_regs all migration
> >> tests fail, without, all of them succeed.
> >>
> >> So env->kvm_guest_debug has been zeroed by cpu_x86_init, which means
> >> the writeback via KVM_SET_GUEST_DEBUG does almost nothing. It does
> >> get_rflags and set_rflags in the kernel.
> >
> > Hmm, it also copies debug regs around... BTW, where do we save/restore
> > dr0..7 between kernel and user space?
> >
> > But that should not be a problem, both shadow as well as effective regs
> > should be properly initialized, specifically for a newly created VCPU.
>
> Could you retry after pushing SET_GUEST_DEBUG at the end of
> kvm_arch_put_registers? Maybe it is no good idea to run get/set_rflags
> without having the sregs properly initialized.
>
> Jan
Can't reproduce (with the original patch, KVM_SET_GUEST_DEBUG at
beginning of arch_put_regs). Different test box though. Go figure.
Anyway, as you mentioned, the workaround can be made cleaner through
set_vcpu_events.
- [Qemu-devel] Re: [PATCH 4/4] KVM: Rework of guest debug state writing, (continued)
- [Qemu-devel] Re: [PATCH 4/4] KVM: Rework of guest debug state writing, Marcelo Tosatti, 2010/02/04
- [Qemu-devel] Re: [PATCH 4/4] KVM: Rework of guest debug state writing, Jan Kiszka, 2010/02/04
- [Qemu-devel] Re: [PATCH 4/4] KVM: Rework of guest debug state writing, Jan Kiszka, 2010/02/04
- [Qemu-devel] Re: [PATCH 4/4] KVM: Rework of guest debug state writing, Marcelo Tosatti, 2010/02/04
- [Qemu-devel] Re: [PATCH 4/4] KVM: Rework of guest debug state writing, Jan Kiszka, 2010/02/04
- [Qemu-devel] Re: [PATCH 4/4] KVM: Rework of guest debug state writing, Jan Kiszka, 2010/02/04
- [Qemu-devel] Re: [PATCH 4/4] KVM: Rework of guest debug state writing, Marcelo Tosatti, 2010/02/08
- [Qemu-devel] Re: [PATCH 4/4] KVM: Rework of guest debug state writing, Jan Kiszka, 2010/02/08
- [Qemu-devel] Re: [PATCH 4/4] KVM: Rework of guest debug state writing, Jan Kiszka, 2010/02/04
- [Qemu-devel] Re: [PATCH 4/4] KVM: Rework of guest debug state writing, Marcelo Tosatti, 2010/02/04
- [Qemu-devel] Re: [PATCH 4/4] KVM: Rework of guest debug state writing,
Marcelo Tosatti <=
[Qemu-devel] [PATCH 3/4] KVM: Move and rename regs_modified, Jan Kiszka, 2010/02/03
[Qemu-devel] [PATCH 1/4] KVM: x86: Fix up misreported CPU features, Jan Kiszka, 2010/02/03
[Qemu-devel] [PATCH 2/4] KVM: Make vmport KVM-compatible, Jan Kiszka, 2010/02/03
Re: [Qemu-devel] [PATCH 0/4] KVM pull request: Various fixes and cleanups, Anthony Liguori, 2010/02/03