Re: [PATCH v2] KVM: SVM: fix interrupt injection (apic->isr_count always 0)

From: Marcelo Tosatti <mtosatti@redhat.com>
To: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	Paolo Bonzini <pbonzini@redhat.com>, Borislav Petkov <bp@suse.de>,
	Tiejun Chen <tiejun.chen@intel.com>
Subject: Re: [PATCH v2] KVM: SVM: fix interrupt injection (apic->isr_count always 0)
Date: Mon, 2 Mar 2015 19:04:58 -0300	[thread overview]
Message-ID: <20150302220457.GA3055@amt.cnet> (raw)
In-Reply-To: <1425051158-32472-1-git-send-email-rkrcmar@redhat.com>

On Fri, Feb 27, 2015 at 04:32:38PM +0100, Radim Krčmář wrote:
> In commit b4eef9b36db4, we started to use hwapic_isr_update() != NULL
> instead of kvm_apic_vid_enabled(vcpu->kvm).  This didn't work because
> SVM had it defined and "apicv" path in apic_{set,clear}_isr() does not
> change apic->isr_count, because it should always be 1.  The initial
> value of apic->isr_count was based on kvm_apic_vid_enabled(vcpu->kvm),
> which is always 0 for SVM, so KVM could have injected interrupts when it
> shouldn't.
> 
> Fix it by implicitly setting SVM's hwapic_isr_update to NULL and make the
> initial isr_count depend on hwapic_isr_update() for good measure.
> 
> Fixes: b4eef9b36db4 ("kvm: x86: vmx: NULL out hwapic_isr_update() in case of !enable_apicv")
> Reported-and-tested-by: Borislav Petkov <bp@suse.de>
> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
> ---
>  v2: set hwapic_isr_update to NULL implicitly [Paolo]
> 
>  arch/x86/kvm/lapic.c | 4 ++--
>  arch/x86/kvm/svm.c   | 6 ------
>  2 files changed, 2 insertions(+), 8 deletions(-)

Applied, thanks.