Re: [PATCH 5/6] KVM: x86: Preserve injected TF across emulation

Gleb Natapov
2010-02-23T10:00:31Z

On Mon, Feb 22, 2010 at 06:51:22PM +0100, Jan Kiszka wrote:
> Call directly into the vendor services for getting/setting rflags in
> emulate_instruction to ensure injected TF survives the emulation.
>
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> ---
> arch/x86/kvm/x86.c | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index e2e03a4..19e8b28 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -3468,7 +3468,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
> kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l);
>
> vcpu->arch.emulate_ctxt.vcpu = vcpu;
> - vcpu->arch.emulate_ctxt.eflags = kvm_get_rflags(vcpu);
> + vcpu->arch.emulate_ctxt.eflags = kvm_x86_ops->get_rflags(vcpu);
So now emulator runs with injected TF? Hmm, then may be emulator should
inject DB when appropriate and caller of emulate_instruction() should
emulate DB intercept if external debugging is going on?

> vcpu->arch.emulate_ctxt.mode =
> (!is_protmode(vcpu)) ? X86EMUL_MODE_REAL :
> (vcpu->arch.emulate_ctxt.eflags & X86_EFLAGS_VM)
> @@ -3547,7 +3547,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
> return EMULATE_DO_MMIO;
> }
>
> - kvm_set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags);
> + kvm_x86_ops->set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags);
>
> if (vcpu->mmio_is_write) {
> vcpu->mmio_needed = 0;
> --
> 1.6.0.2

--
Gleb.