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From: Avi Kivity <avi@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: kvm@vger.kernel.org
Subject: [PATCH 05/13] KVM: VMX: Allow real mode emulation using vm86 with dpl=0
Date: Tue, 21 Aug 2012 17:07:02 +0300	[thread overview]
Message-ID: <1345558030-29370-6-git-send-email-avi@redhat.com> (raw)
In-Reply-To: <1345558030-29370-1-git-send-email-avi@redhat.com>

Real mode is always entered from protected mode with dpl=0.  Since
the dpl doesn't affect execution, and we already override it to 3
in the vmcs (as vmx requires), we can allow execution in that state.

Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/kvm/vmx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e94b90b..4f3d6ac 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3318,7 +3318,7 @@ static bool rmode_segment_valid(struct kvm_vcpu *vcpu, int seg)
 		return false;
 	if (var.limit != 0xffff)
 		return false;
-	if (ar != 0xf3)
+	if ((ar | (3 << AR_DPL_SHIFT)) != 0xf3)
 		return false;
 
 	return true;
-- 
1.7.11.3


  parent reply	other threads:[~2012-08-21 14:07 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-21 14:06 [PATCH 00/13] Big real mode fixes Avi Kivity
2012-08-21 14:06 ` [PATCH 01/13] KVM: VMX: Separate saving pre-realmode state from setting segments Avi Kivity
2012-08-21 14:06 ` [PATCH 02/13] KVM: VMX: Fix incorrect lookup of segment S flag in fix_pmode_dataseg() Avi Kivity
2012-08-21 14:07 ` [PATCH 03/13] KVM: VMX: Use kvm_segment to save protected-mode segments when entering realmode Avi Kivity
2012-08-21 14:07 ` [PATCH 04/13] KVM: VMX: Retain limit and attributes when entering protected mode Avi Kivity
2012-08-21 14:07 ` Avi Kivity [this message]
2012-08-21 14:07 ` [PATCH 06/13] KVM: VMX: Allow vm86 virtualization of big real mode Avi Kivity
2012-08-21 14:07 ` [PATCH 07/13] KVM: x86 emulator: Leave segment limit and attributs alone in " Avi Kivity
2012-08-21 14:07 ` [PATCH 08/13] KVM: x86 emulator: Check segment limits in real mode too Avi Kivity
2012-08-21 14:07 ` [PATCH 09/13] KVM: x86 emulator: Fix #GP error code during linearization Avi Kivity
2012-08-21 14:07 ` [PATCH 10/13] KVM: VMX: Return real real-mode segment data even if emulate_invalid_guest_state=1 Avi Kivity
2012-08-21 14:07 ` [PATCH 11/13] KVM: VMX: Preserve segment limit and access rights in real mode Avi Kivity
2012-08-21 14:07 ` [PATCH 12/13] KVM: VMX: Save all segment data " Avi Kivity
2012-08-21 14:07 ` [PATCH 13/13] KVM: VMX: Ignore segment G and D bits when considering whether we can virtualize Avi Kivity
2012-08-28  0:08 ` [PATCH 00/13] Big real mode fixes Marcelo Tosatti

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