From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Jim Mattson <jmattson@google.com>,
kvm@vger.kernel.org, Oliver Upton <oupton@google.com>,
Peter Shier <pshier@google.com>
Subject: Re: [PATCH 2/2] kvm: nVMX: Single-step traps trump expired VMX-preemption timer
Date: Wed, 22 Apr 2020 08:48:55 -0700 [thread overview]
Message-ID: <20200422154855.GA4662@linux.intel.com> (raw)
In-Reply-To: <83426123-eca6-568d-ac3e-36c4e3ca3030@redhat.com>
On Wed, Apr 22, 2020 at 10:30:28AM +0200, Paolo Bonzini wrote:
> On 14/04/20 02:09, Jim Mattson wrote:
> > Previously, if the hrtimer for the nested VMX-preemption timer fired
> > while L0 was emulating an L2 instruction with RFLAGS.TF set, the
> > synthesized single-step trap would be unceremoniously dropped when
> > synthesizing the "VMX-preemption timer expired" VM-exit from L2 to L1.
> >
> > To fix this, don't synthesize a "VMX-preemption timer expired" VM-exit
> > from L2 to L1 when there is a pending debug trap, such as a
> > single-step trap.
>
> Do you have a testcase for these bugs?
Just in case you're feeling trigger happy, I'm working on a set of patches
to fix this in a more generic fashion. Well, fixing this specific issue
can be done in a single patch, but NMIs and interrupts technically suffer
from the same bug and fixing those requires a bit of extra elbow grease.
There are also (theoretical) bugs related to nested exceptions and
interrupt injection that I'm trying to address. Unfortunately I don't have
testcases for any of this :-(.
next prev parent reply other threads:[~2020-04-22 15:49 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-14 0:09 [PATCH 1/2] kvm: nVMX: Pending debug exceptions trump expired VMX-preemption timer Jim Mattson
2020-04-14 0:09 ` [PATCH 2/2] kvm: nVMX: Single-step traps " Jim Mattson
2020-04-14 3:17 ` Sean Christopherson
2020-04-14 16:47 ` Jim Mattson
2020-04-15 0:12 ` Sean Christopherson
2020-04-15 0:20 ` Sean Christopherson
2020-04-15 0:22 ` Sean Christopherson
2020-04-15 23:33 ` Jim Mattson
2020-04-18 4:21 ` Sean Christopherson
2020-04-20 17:18 ` Jim Mattson
2020-04-21 4:41 ` Sean Christopherson
2020-04-21 18:28 ` Jim Mattson
2020-04-22 0:16 ` Sean Christopherson
2020-04-22 8:30 ` Paolo Bonzini
2020-04-22 15:48 ` Sean Christopherson [this message]
2020-04-22 16:28 ` Jim Mattson
2020-04-22 16:42 ` Sean Christopherson
2020-04-22 21:06 ` [PATCH 1/2] kvm: nVMX: Pending debug exceptions " Sean Christopherson
2020-04-22 21:23 ` Sean Christopherson
2020-04-22 21:27 ` Jim Mattson
2020-04-22 22:06 ` Sean Christopherson
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