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From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	vkuznets@redhat.com, mlevitsk@redhat.com,
	Jim Mattson <jmattson@google.com>
Subject: Re: [PATCH 03/28] KVM: nSVM: inject exceptions via svm_check_nested_events
Date: Mon, 8 Mar 2021 12:43:48 -0800	[thread overview]
Message-ID: <YEaMhHG7ylvTpoYD@google.com> (raw)
In-Reply-To: <006be822-697e-56d5-84a7-fa51f5087a34@redhat.com>

On Mon, Mar 08, 2021, Paolo Bonzini wrote:
> On 08/03/21 17:44, Sean Christopherson wrote:
> > VMCALL is also probably ok
> > in most scenarios, but patching L2's code from L0 KVM is sketchy.
> 
> I agree that patching is sketchy and I'll send a patch.  However...
> 
> > > The same is true for the VMware #GP interception case.
> > 
> > I highly doubt that will ever work out as intended for the modified IO #GP
> > behavior.  The only way emulating #GP in L2 is correct if L1 wants to pass
> > through the capabilities to L2, i.e. the I/O access isn't intercepted by L1.
> > That seems unlikely.
> 
> ... not all hypervisors trap everything.  In particular in this case the
> VMCS12 I/O permission bitmap should be consulted (which we do in
> vmx_check_intercept_io), but if the I/O is not trapped by L1 it should
> bypass the IOPL and TSS-bitmap checks in my opinion.

I agree, _if_ it's not trapped.  But bypassing the checks when it is trapped is
clearly wrong.

  reply	other threads:[~2021-03-08 20:44 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-26 17:22 [PATCH v2 00/28] KVM: nSVM: event fixes and migration support Paolo Bonzini
2020-05-26 17:22 ` [PATCH 01/28] KVM: x86: track manually whether an event has been injected Paolo Bonzini
2020-05-26 17:22 ` [PATCH 02/28] KVM: x86: enable event window in inject_pending_event Paolo Bonzini
2020-05-29  2:16   ` Krish Sadhukhan
2020-05-29  8:47     ` Paolo Bonzini
2020-05-26 17:22 ` [PATCH 03/28] KVM: nSVM: inject exceptions via svm_check_nested_events Paolo Bonzini
2021-03-06  1:39   ` Sean Christopherson
2021-03-06  9:26     ` Paolo Bonzini
2021-03-08 16:44       ` Sean Christopherson
2021-03-08 17:28         ` Paolo Bonzini
2021-03-08 20:43           ` Sean Christopherson [this message]
2021-03-08 22:51             ` Paolo Bonzini
2020-05-26 17:22 ` [PATCH 04/28] KVM: nSVM: remove exit_required Paolo Bonzini
2020-05-26 17:22 ` [PATCH 05/28] KVM: nSVM: correctly inject INIT vmexits Paolo Bonzini
2020-05-29  6:46   ` Krish Sadhukhan
2020-05-29  8:47     ` Paolo Bonzini
2020-05-26 17:22 ` [PATCH 06/28] KVM: SVM: always update CR3 in VMCB Paolo Bonzini
2020-05-26 17:22 ` [PATCH 07/28] KVM: nVMX: always update CR3 in VMCS Paolo Bonzini
2020-05-26 17:22 ` [PATCH 08/28] KVM: nSVM: move map argument out of enter_svm_guest_mode Paolo Bonzini
2020-05-26 17:22 ` [PATCH 09/28] KVM: nSVM: extract load_nested_vmcb_control Paolo Bonzini
2020-05-26 17:22 ` [PATCH 10/28] KVM: nSVM: extract preparation of VMCB for nested run Paolo Bonzini
2020-05-26 17:22 ` [PATCH 11/28] KVM: nSVM: move MMU setup to nested_prepare_vmcb_control Paolo Bonzini
2020-05-26 17:22 ` [PATCH 12/28] KVM: nSVM: clean up tsc_offset update Paolo Bonzini
2020-05-26 17:22 ` [PATCH 13/28] KVM: nSVM: pass vmcb_control_area to copy_vmcb_control_area Paolo Bonzini
2020-05-26 17:22 ` [PATCH 14/28] KVM: nSVM: remove trailing padding for struct vmcb_control_area Paolo Bonzini
2020-05-26 17:22 ` [PATCH 15/28] KVM: nSVM: save all control fields in svm->nested Paolo Bonzini
2020-05-26 17:22 ` [PATCH 16/28] KVM: nSVM: restore clobbered INT_CTL fields after clearing VINTR Paolo Bonzini
2020-05-26 17:22 ` [PATCH 17/28] KVM: nSVM: synchronize VMCB controls updated by the processor on every vmexit Paolo Bonzini
2020-05-26 17:22 ` [PATCH 18/28] KVM: nSVM: remove unnecessary if Paolo Bonzini
2020-05-26 17:22 ` [PATCH 19/28] KVM: nSVM: extract svm_set_gif Paolo Bonzini
2020-05-26 17:23 ` [PATCH 20/28] KVM: SVM: preserve VGIF across VMCB switch Paolo Bonzini
2020-05-26 17:23 ` [PATCH 21/28] KVM: nSVM: synthesize correct EXITINTINFO on vmexit Paolo Bonzini
2020-05-26 17:23 ` [PATCH 22/28] KVM: nSVM: remove HF_VINTR_MASK Paolo Bonzini
2020-05-26 17:23 ` [PATCH 23/28] KVM: nSVM: remove HF_HIF_MASK Paolo Bonzini
2020-05-26 17:23 ` [PATCH 24/28] KVM: nSVM: split nested_vmcb_check_controls Paolo Bonzini
2020-05-26 17:23 ` [PATCH 25/28] KVM: nSVM: leave guest mode when clearing EFER.SVME Paolo Bonzini
2020-05-26 17:23 ` [PATCH 26/28] KVM: MMU: pass arbitrary CR0/CR4/EFER to kvm_init_shadow_mmu Paolo Bonzini
2020-05-26 17:23 ` [PATCH 27/28] selftests: kvm: add a SVM version of state-test Paolo Bonzini
2020-05-26 17:23 ` [PATCH 28/28] KVM: nSVM: implement KVM_GET_NESTED_STATE and KVM_SET_NESTED_STATE Paolo Bonzini

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