On Mon, Jun 24, 2013 at 10:42:57PM +0200, Stefan Pietsch wrote:
> On 24.06.2013 14:30, Gleb Natapov wrote:
> > On Mon, Jun 24, 2013 at 01:59:34PM +0200, Stefan Pietsch wrote:
> >> As soon as I remove "kvmvapic.bin" the virtual machine boots with
> >> qemu-kvm 1.5.0. I just verified this with Linux kernel 3.10.0-rc5.
> >> "emulate_invalid_guest_state=0" or "emulate_invalid_guest_state=1" make
> >> no difference.
> >>
> >> Please send your patches.
> > Here it is, run with it and kvmvapic.bin present. See what is printed in
> > dmesg after the failure.
> >
> >
> > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> > index f4a5b3f..65488a4 100644
> > --- a/arch/x86/kvm/vmx.c
> > +++ b/arch/x86/kvm/vmx.c
> > @@ -3385,6 +3385,7 @@ static void vmx_get_segment(struct kvm_vcpu *vcpu,
> > {
> > struct vcpu_vmx *vmx = to_vmx(vcpu);
> > u32 ar;
> > + unsigned long rip;
> >
> > if (vmx->rmode.vm86_active && seg != VCPU_SREG_LDTR) {
> > *var = vmx->rmode.segs[seg];
> > @@ -3408,6 +3409,9 @@ static void vmx_get_segment(struct kvm_vcpu *vcpu,
> > var->db = (ar >> 14) & 1;
> > var->g = (ar >> 15) & 1;
> > var->unusable = (ar >> 16) & 1;
> > + rip = kvm_rip_read(vcpu);
> > + if ((rip == 0xc101611c || rip == 0xc101611a) && seg == VCPU_SREG_FS)
> > + printk("base=%p limit=%p selector=%x ar=%x\n", var->base, var->limit, var->selector, ar);
> > }
> >
> > static u64 vmx_get_segment_base(struct kvm_vcpu *vcpu, int seg)
>
>
> Booting kernel Linux 3.10-rc5 with your patch applied produces these
> messages in dmesg when starting a virtual machine:
>
> emulate_invalid_guest_state=0
> [ 118.732151] base=ffff0000 limit= (null) selector=f0000fff ar=0
> [ 118.732341] base=ffff0000 limit= (null) selector=f0000fff ar=0
>
I've butchered printk format, but it gives me the idea of what is going
on anyway. Can you try the patch below with
emulate_invalid_guest_state=0|1?
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index f4a5b3f..eb062ce 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3395,19 +3395,20 @@ static void vmx_get_segment(struct kvm_vcpu *vcpu,
var->selector = vmx_read_guest_seg_selector(vmx, seg);
return;
}
+
var->base = vmx_read_guest_seg_base(vmx, seg);
var->limit = vmx_read_guest_seg_limit(vmx, seg);
var->selector = vmx_read_guest_seg_selector(vmx, seg);
ar = vmx_read_guest_seg_ar(vmx, seg);
+ var->unusable = (ar >> 16) & 1;
var->type = ar & 15;
var->s = (ar >> 4) & 1;
var->dpl = (ar >> 5) & 3;
- var->present = (ar >> 7) & 1;
+ var->present = !var->unusable;
var->avl = (ar >> 12) & 1;
var->l = (ar >> 13) & 1;
var->db = (ar >> 14) & 1;
var->g = (ar >> 15) & 1;
- var->unusable = (ar >> 16) & 1;
}
static u64 vmx_get_segment_base(struct kvm_vcpu *vcpu, int seg)
--
Gleb.
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