From: Sean Christopherson <seanjc@google.com>
To: Chao Gao <chao.gao@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Zeng Guang <guang.zeng@intel.com>
Subject: Re: [PATCH 0/6] KVM: nVMX: Fix IPIv vs. nested posted interrupts
Date: Mon, 22 Jul 2024 16:58:06 -0700 [thread overview]
Message-ID: <Zp7yDvcwfPtgED0j@google.com> (raw)
In-Reply-To: <Zp5Wq1h40JMSYL5a@chao-email>
On Mon, Jul 22, 2024, Chao Gao wrote:
> On Fri, Jul 19, 2024 at 05:01:32PM -0700, Sean Christopherson wrote:
> >Fix a bug where KVM injects L2's nested posted interrupt into L1 as a
> >nested VM-Exit instead of triggering PI processing. The actual bug is
> >technically a generic nested posted interrupts problem, but due to the
> >way that KVM handles interrupt delivery, I'm 99.9% certain the issue is
> >limited to IPI virtualization being enabled.
>
> Theoretically VT-d posted interrupt can also trigger this issue.
Hmm, yeah, I think you're right. L1 could program an assigned device to _post_
an interrupt to L2's vector, via L1's PID.PIR. Which would let the interrupt
into vIRR without KVM checking vmcs12's NV. It seems unlikely L1 would do that,
but it definitely seems possible.
Unless I'm missing something (else), I'll update the changelog and Fixes: to make
it clear that IPI virtualization just makes the bug easier to hit, but that the
issue exists with nested assigned devices, too.
next prev parent reply other threads:[~2024-07-22 23:58 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-20 0:01 [PATCH 0/6] KVM: nVMX: Fix IPIv vs. nested posted interrupts Sean Christopherson
2024-07-20 0:01 ` [PATCH 1/6] KVM: nVMX: Get to-be-acknowledge IRQ for nested VM-Exit at injection site Sean Christopherson
2024-09-04 21:08 ` Nathan Chancellor
2024-09-04 22:49 ` Sean Christopherson
2024-09-05 0:37 ` Sean Christopherson
2024-07-20 0:01 ` [PATCH 2/6] KVM: nVMX: Suppress external interrupt VM-Exit injection if there's no IRQ Sean Christopherson
2024-07-20 0:01 ` [PATCH 3/6] KVM: x86: Don't move VMX's nested PI notification vector from IRR to ISR Sean Christopherson
2024-07-20 0:01 ` [PATCH 4/6] KVM: nVMX: Track nested_vmx.posted_intr_nv as a signed int Sean Christopherson
2024-07-20 0:01 ` [PATCH 5/6] KVM: nVMX: Explicitly invalidate posted_intr_nv if PI is disabled at VM-Enter Sean Christopherson
2024-07-20 0:01 ` [PATCH 6/6] KVM: nVMX: Detect nested posted interrupt NV at nested VM-Exit injection Sean Christopherson
2024-07-23 14:49 ` Chao Gao
2024-07-23 17:43 ` Sean Christopherson
2024-07-22 12:55 ` [PATCH 0/6] KVM: nVMX: Fix IPIv vs. nested posted interrupts Chao Gao
2024-07-22 23:58 ` Sean Christopherson [this message]
2024-08-31 0:21 ` Sean Christopherson
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