linux-kernel - Re: Qemu e1000 broken in -rc1 and -rc2 : bisected

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Message-ID: <20150306192728.GA5032@milliways>
Date:	Fri, 6 Mar 2015 19:27:28 +0000
From:	Ken Moffat <zarniwhoop@...world.com>
To:	Tiejun Chen <tiejun.chen@...el.com>,
	Paolo Bonzini <pbonzini@...hat.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: Qemu e1000 broken in -rc1 and -rc2 : bisected

On Fri, Mar 06, 2015 at 12:02:40AM +0000, Ken Moffat wrote:
>  I have a very recent qemu i686 image, using a 3.19.0 kernel and
> dhclient, which works fine if the host is running a 3.19.0 kernel,
> but breaks when the host runs 4.0.0-rc1 or -rc2.
> 
>  On those, dhclient does not get an address, so I have no network.
> There is a message
> e1000 0000:00:03.0 eth0: Reset adaptor
> 
>  Before I start trying to bisect this, has anybody already seen, or
> fixed, it ?
> 
 Bisected.
b4eef9b36db461ca44832226fbca614db58c0c33 is the first bad commit
commit b4eef9b36db461ca44832226fbca614db58c0c33
Author: Tiejun Chen <tiejun.chen@...el.com>
Date:   Mon Dec 22 10:32:57 2014 +0100

    kvm: x86: vmx: NULL out hwapic_isr_update() in case of
!enable_apicv
    
    In most cases calling hwapic_isr_update(), we always check if
    kvm_apic_vid_enabled() == 1, but actually,
    kvm_apic_vid_enabled()
        -> kvm_x86_ops->vm_has_apicv()
            -> vmx_vm_has_apicv() or '0' in svm case
                -> return enable_apicv && irqchip_in_kernel(kvm)
    
    So its a little cost to recall vmx_vm_has_apicv() inside
    hwapic_isr_update(), here just NULL out hwapic_isr_update() in
    case of !enable_apicv inside hardware_setup() then make all
    related stuffs follow this. Note we don't check this under that
    condition of irqchip_in_kernel() since we should make sure
    definitely any caller don't work  without in-kernel irqchip.
    
    Signed-off-by: Tiejun Chen <tiejun.chen@...el.com>
    Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>

 I have reverted this from -rc2 (big offsets, 209 and 357 lines) and
everything is working again.

ĸen
-- 
Nanny Ogg usually went to bed early. After all, she was an old lady.
Sometimes she went to bed as early as 6 a.m.
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