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From: Paul Mackerras <paulus@samba.org>
To: Dinar Valeev <dvaleev@suse.de>, Alexander Graf <agraf@suse.de>
Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org
Subject: [PATCH 2/2] KVM: PPC: Book3S HV: Allow negative offsets to real-mode hcall handlers
Date: Mon, 8 Jul 2013 20:09:53 +1000	[thread overview]
Message-ID: <20130708100953.GD24032@iris.ozlabs.ibm.com> (raw)
In-Reply-To: <20130708100825.GC24032@iris.ozlabs.ibm.com>

The table of offsets to real-mode hcall handlers in book3s_hv_rmhandlers.S
can contain negative values, if some of the handlers end up before the
table in the vmlinux binary.  Thus we need to use a sign-extending load
to read the values in the table rather than a zero-extending load.
Without this, the host crashes when the guest does one of the hcalls
with negative offsets, due to jumping to a bogus address.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: stable@vger.kernel.org
---
 arch/powerpc/kvm/book3s_hv_rmhandlers.S | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index b02f91e..60dce5b 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -1381,7 +1381,7 @@ hcall_try_real_mode:
 	cmpldi	r3,hcall_real_table_end - hcall_real_table
 	bge	guest_exit_cont
 	LOAD_REG_ADDR(r4, hcall_real_table)
-	lwzx	r3,r3,r4
+	lwax	r3,r3,r4
 	cmpwi	r3,0
 	beq	guest_exit_cont
 	add	r3,r3,r4
-- 
1.8.3.1

WARNING: multiple messages have this Message-ID (diff)
From: Paul Mackerras <paulus@samba.org>
To: Dinar Valeev <dvaleev@suse.de>, Alexander Graf <agraf@suse.de>
Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org
Subject: [PATCH 2/2] KVM: PPC: Book3S HV: Allow negative offsets to real-mode hcall handlers
Date: Mon, 08 Jul 2013 10:09:53 +0000	[thread overview]
Message-ID: <20130708100953.GD24032@iris.ozlabs.ibm.com> (raw)
In-Reply-To: <20130708100825.GC24032@iris.ozlabs.ibm.com>

The table of offsets to real-mode hcall handlers in book3s_hv_rmhandlers.S
can contain negative values, if some of the handlers end up before the
table in the vmlinux binary.  Thus we need to use a sign-extending load
to read the values in the table rather than a zero-extending load.
Without this, the host crashes when the guest does one of the hcalls
with negative offsets, due to jumping to a bogus address.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: stable@vger.kernel.org
---
 arch/powerpc/kvm/book3s_hv_rmhandlers.S | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index b02f91e..60dce5b 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -1381,7 +1381,7 @@ hcall_try_real_mode:
 	cmpldi	r3,hcall_real_table_end - hcall_real_table
 	bge	guest_exit_cont
 	LOAD_REG_ADDR(r4, hcall_real_table)
-	lwzx	r3,r3,r4
+	lwax	r3,r3,r4
 	cmpwi	r3,0
 	beq	guest_exit_cont
 	add	r3,r3,r4
-- 
1.8.3.1


  reply	other threads:[~2013-07-08 10:09 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-08 10:08 [PATCH 1/2] KVM: PPC: Book3S HV: Correct tlbie usage Paul Mackerras
2013-07-08 10:08 ` Paul Mackerras
2013-07-08 10:09 ` Paul Mackerras [this message]
2013-07-08 10:09   ` [PATCH 2/2] KVM: PPC: Book3S HV: Allow negative offsets to real-mode hcall handlers Paul Mackerras
2013-07-10 11:15 ` [PATCH 1/2] KVM: PPC: Book3S HV: Correct tlbie usage Alexander Graf
2013-07-10 11:15   ` Alexander Graf
2013-07-17 10:40 ` Aneesh Kumar K.V
2013-07-17 10:52   ` Aneesh Kumar K.V

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