From: Paolo Bonzini <pbonzini@redhat.com>
To: "Radim Krčmář" <rkrcmar@redhat.com>, linux-kernel@vger.kernel.org
Cc: kvm@vger.kernel.org, Steve Rutherford <srutherford@google.com>,
stable@vger.kernel.org
Subject: Re: [PATCH 2/2] KVM: x86: fix edge EOI and IOAPIC reconfig race
Date: Thu, 13 Aug 2015 16:53:17 +0200 [thread overview]
Message-ID: <55CCAF5D.8050204@redhat.com> (raw)
In-Reply-To: <1439473570-13763-3-git-send-email-rkrcmar@redhat.com>
On 13/08/2015 15:46, Radim Krčmář wrote:
> 1) IOAPIC inject a vector from i8254
> 2) guest reconfigures that vector's VCPU and therefore eoi_exit_bitmap
> on original VCPU gets cleared
> 3) guest's handler for the vector does EOI
> 4) KVM's EOI handler doesn't pass that vector to IOAPIC because it is
> not in that VCPU's eoi_exit_bitmap
> 5) i8254 stops working
>
> This creates an unwanted situation if the vector is reused by a
> non-IOAPIC source, but I think it is so rare that we don't want to make
> the solution more sophisticated.
What happens if the vector is changed in step 2?
__kvm_ioapic_update_eoi won't match the redirection table entry.
How do you reproduce the bug?
Paolo
next prev parent reply other threads:[~2015-08-13 14:53 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-13 13:46 [PATCH 0/2] KVM: x86: fix edge EOI and IOAPIC reconfig race Radim Krčmář
2015-08-13 13:46 ` [PATCH 1/2] KVM: x86: return bool from x86_ops.sync_pir_to_irr Radim Krčmář
2015-08-13 13:46 ` [PATCH 2/2] KVM: x86: fix edge EOI and IOAPIC reconfig race Radim Krčmář
2015-08-13 14:53 ` Paolo Bonzini [this message]
2015-08-14 8:38 ` Radim Krčmář
2015-08-15 0:00 ` Paolo Bonzini
2015-10-06 20:33 ` Radim Krčmář
2015-10-07 9:31 ` Paolo Bonzini
2015-10-07 15:05 ` Radim Krčmář
2015-10-07 9:29 ` Paolo Bonzini
2015-10-07 15:01 ` Radim Krčmář
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