* [RESEND PATCH] KVM: PPC: Book3S HV: Deliver machine check with MSR(RI=0) to guest as MCE.
@ 2015-03-23 16:54 ` Mahesh J Salgaonkar
0 siblings, 0 replies; 3+ messages in thread
From: Mahesh J Salgaonkar @ 2015-03-23 16:54 UTC (permalink / raw
To: linuxppc-dev, Paul Mackerras, Michael Ellerman
Cc: David Gibson, Alexander Graf, KVM-PPC, KVM
From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
For the machine check interrupt that happens while we are in the guest,
kvm layer attempts the recovery, and then delivers the machine check interrupt
directly to the guest if recovery fails. On successful recovery we go back to
normal functioning of the guest. But there can be cases where a machine check
interrupt can happen with MSR(RI=0) while we are in the guest. This means
MC interrupt is unrecoverable and we have to deliver a machine check to the
guest since the machine check interrupt might have trashed valid values in
SRR0/1. The current implementation do not handle this case, causing guest
to crash with Bad kernel stack pointer instead of machine check oops message.
[26281.490060] Bad kernel stack pointer 3fff9ccce5b0 at c00000000000490c
[26281.490434] Oops: Bad kernel stack pointer, sig: 6 [#1]
[26281.490472] SMP NR_CPUS=2048 NUMA pSeries
This patch fixes this issue by checking MSR(RI=0) in KVM layer and forwarding
unrecoverable interrupt to guest which then panics with proper machine check
Oops message.
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
---
arch/powerpc/kvm/book3s_hv_rmhandlers.S | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index bb94e6f..258f46d 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -2063,7 +2063,6 @@ machine_check_realmode:
mr r3, r9 /* get vcpu pointer */
bl kvmppc_realmode_machine_check
nop
- cmpdi r3, 0 /* Did we handle MCE ? */
ld r9, HSTATE_KVM_VCPU(r13)
li r12, BOOK3S_INTERRUPT_MACHINE_CHECK
/*
@@ -2076,13 +2075,18 @@ machine_check_realmode:
* The old code used to return to host for unhandled errors which
* was causing guest to hang with soft lockups inside guest and
* makes it difficult to recover guest instance.
+ *
+ * if we receive machine check with MSR(RI=0) then deliver it to
+ * guest as machine check causing guest to crash.
*/
- ld r10, VCPU_PC(r9)
ld r11, VCPU_MSR(r9)
+ andi. r10, r11, MSR_RI /* check for unrecoverable exception */
+ beq 1f /* Deliver a machine check to guest */
+ ld r10, VCPU_PC(r9)
+ cmpdi r3, 0 /* Did we handle MCE ? */
bne 2f /* Continue guest execution. */
/* If not, deliver a machine check. SRR0/1 are already set */
- li r10, BOOK3S_INTERRUPT_MACHINE_CHECK
- ld r11, VCPU_MSR(r9)
+1: li r10, BOOK3S_INTERRUPT_MACHINE_CHECK
bl kvmppc_msr_interrupt
2: b fast_interrupt_c_return
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [RESEND PATCH] KVM: PPC: Book3S HV: Deliver machine check with MSR(RI=0) to guest as MCE.
@ 2015-03-23 16:54 ` Mahesh J Salgaonkar
0 siblings, 0 replies; 3+ messages in thread
From: Mahesh J Salgaonkar @ 2015-03-23 16:54 UTC (permalink / raw
To: linuxppc-dev, Paul Mackerras, Michael Ellerman
Cc: KVM-PPC, David Gibson, Alexander Graf, KVM
From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
For the machine check interrupt that happens while we are in the guest,
kvm layer attempts the recovery, and then delivers the machine check interrupt
directly to the guest if recovery fails. On successful recovery we go back to
normal functioning of the guest. But there can be cases where a machine check
interrupt can happen with MSR(RI=0) while we are in the guest. This means
MC interrupt is unrecoverable and we have to deliver a machine check to the
guest since the machine check interrupt might have trashed valid values in
SRR0/1. The current implementation do not handle this case, causing guest
to crash with Bad kernel stack pointer instead of machine check oops message.
[26281.490060] Bad kernel stack pointer 3fff9ccce5b0 at c00000000000490c
[26281.490434] Oops: Bad kernel stack pointer, sig: 6 [#1]
[26281.490472] SMP NR_CPUS=2048 NUMA pSeries
This patch fixes this issue by checking MSR(RI=0) in KVM layer and forwarding
unrecoverable interrupt to guest which then panics with proper machine check
Oops message.
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
---
arch/powerpc/kvm/book3s_hv_rmhandlers.S | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index bb94e6f..258f46d 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -2063,7 +2063,6 @@ machine_check_realmode:
mr r3, r9 /* get vcpu pointer */
bl kvmppc_realmode_machine_check
nop
- cmpdi r3, 0 /* Did we handle MCE ? */
ld r9, HSTATE_KVM_VCPU(r13)
li r12, BOOK3S_INTERRUPT_MACHINE_CHECK
/*
@@ -2076,13 +2075,18 @@ machine_check_realmode:
* The old code used to return to host for unhandled errors which
* was causing guest to hang with soft lockups inside guest and
* makes it difficult to recover guest instance.
+ *
+ * if we receive machine check with MSR(RI=0) then deliver it to
+ * guest as machine check causing guest to crash.
*/
- ld r10, VCPU_PC(r9)
ld r11, VCPU_MSR(r9)
+ andi. r10, r11, MSR_RI /* check for unrecoverable exception */
+ beq 1f /* Deliver a machine check to guest */
+ ld r10, VCPU_PC(r9)
+ cmpdi r3, 0 /* Did we handle MCE ? */
bne 2f /* Continue guest execution. */
/* If not, deliver a machine check. SRR0/1 are already set */
- li r10, BOOK3S_INTERRUPT_MACHINE_CHECK
- ld r11, VCPU_MSR(r9)
+1: li r10, BOOK3S_INTERRUPT_MACHINE_CHECK
bl kvmppc_msr_interrupt
2: b fast_interrupt_c_return
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [RESEND PATCH] KVM: PPC: Book3S HV: Deliver machine check with MSR(RI=0) to guest as MCE.
@ 2015-03-23 16:54 ` Mahesh J Salgaonkar
0 siblings, 0 replies; 3+ messages in thread
From: Mahesh J Salgaonkar @ 2015-03-23 16:54 UTC (permalink / raw
To: linuxppc-dev, Paul Mackerras, Michael Ellerman
Cc: KVM-PPC, David Gibson, Alexander Graf, KVM
From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
For the machine check interrupt that happens while we are in the guest,
kvm layer attempts the recovery, and then delivers the machine check interrupt
directly to the guest if recovery fails. On successful recovery we go back to
normal functioning of the guest. But there can be cases where a machine check
interrupt can happen with MSR(RI=0) while we are in the guest. This means
MC interrupt is unrecoverable and we have to deliver a machine check to the
guest since the machine check interrupt might have trashed valid values in
SRR0/1. The current implementation do not handle this case, causing guest
to crash with Bad kernel stack pointer instead of machine check oops message.
[26281.490060] Bad kernel stack pointer 3fff9ccce5b0 at c00000000000490c
[26281.490434] Oops: Bad kernel stack pointer, sig: 6 [#1]
[26281.490472] SMP NR_CPUS 48 NUMA pSeries
This patch fixes this issue by checking MSR(RI=0) in KVM layer and forwarding
unrecoverable interrupt to guest which then panics with proper machine check
Oops message.
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
---
arch/powerpc/kvm/book3s_hv_rmhandlers.S | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index bb94e6f..258f46d 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -2063,7 +2063,6 @@ machine_check_realmode:
mr r3, r9 /* get vcpu pointer */
bl kvmppc_realmode_machine_check
nop
- cmpdi r3, 0 /* Did we handle MCE ? */
ld r9, HSTATE_KVM_VCPU(r13)
li r12, BOOK3S_INTERRUPT_MACHINE_CHECK
/*
@@ -2076,13 +2075,18 @@ machine_check_realmode:
* The old code used to return to host for unhandled errors which
* was causing guest to hang with soft lockups inside guest and
* makes it difficult to recover guest instance.
+ *
+ * if we receive machine check with MSR(RI=0) then deliver it to
+ * guest as machine check causing guest to crash.
*/
- ld r10, VCPU_PC(r9)
ld r11, VCPU_MSR(r9)
+ andi. r10, r11, MSR_RI /* check for unrecoverable exception */
+ beq 1f /* Deliver a machine check to guest */
+ ld r10, VCPU_PC(r9)
+ cmpdi r3, 0 /* Did we handle MCE ? */
bne 2f /* Continue guest execution. */
/* If not, deliver a machine check. SRR0/1 are already set */
- li r10, BOOK3S_INTERRUPT_MACHINE_CHECK
- ld r11, VCPU_MSR(r9)
+1: li r10, BOOK3S_INTERRUPT_MACHINE_CHECK
bl kvmppc_msr_interrupt
2: b fast_interrupt_c_return
^ permalink raw reply related [flat|nested] 3+ messages in thread
end of thread, other threads:[~2015-03-23 16:54 UTC | newest]
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2015-03-23 16:54 [RESEND PATCH] KVM: PPC: Book3S HV: Deliver machine check with MSR(RI=0) to guest as MCE Mahesh J Salgaonkar
2015-03-23 16:54 ` Mahesh J Salgaonkar
2015-03-23 16:54 ` Mahesh J Salgaonkar
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