4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Paul Mackerras <paulus@xxxxxxxxxx>
commit 43ff3f65234061e08d234bdef5a9aadc19832b74 upstream.
This fixes a bug where it is possible to enter a guest on a POWER9
system without having the XIVE (interrupt controller) context loaded.
This can happen because we unload the XIVE context from the CPU
before doing the real-mode handling for machine checks. After the
real-mode handler runs, it is possible that we re-enter the guest
via a fast path which does not load the XIVE context.
To fix this, we move the unloading of the XIVE context to come after
the real-mode machine check handler is called.
Fixes: 5af50993850a ("KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controller")
Signed-off-by: Paul Mackerras <paulus@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/kvm/book3s_hv_rmhandlers.S | 40 ++++++++++++++++----------------
1 file changed, 20 insertions(+), 20 deletions(-)
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -1387,6 +1387,26 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
blt deliver_guest_interrupt
guest_exit_cont: /* r9 = vcpu, r12 = trap, r13 = paca */
+ /* Save more register state */
+ mfdar r6
+ mfdsisr r7
+ std r6, VCPU_DAR(r9)
+ stw r7, VCPU_DSISR(r9)
+ /* don't overwrite fault_dar/fault_dsisr if HDSI */
+ cmpwi r12,BOOK3S_INTERRUPT_H_DATA_STORAGE
+ beq mc_cont
+ std r6, VCPU_FAULT_DAR(r9)
+ stw r7, VCPU_FAULT_DSISR(r9)
+
+ /* See if it is a machine check */
+ cmpwi r12, BOOK3S_INTERRUPT_MACHINE_CHECK
+ beq machine_check_realmode
+mc_cont:
+#ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING
+ addi r3, r9, VCPU_TB_RMEXIT
+ mr r4, r9
+ bl kvmhv_accumulate_time
+#endif
#ifdef CONFIG_KVM_XICS
/* We are exiting, pull the VP from the XIVE */
lwz r0, VCPU_XIVE_PUSHED(r9)
@@ -1424,26 +1444,6 @@ guest_exit_cont: /* r9 = vcpu, r12 = tr
eieio
1:
#endif /* CONFIG_KVM_XICS */
- /* Save more register state */
- mfdar r6
- mfdsisr r7
- std r6, VCPU_DAR(r9)
- stw r7, VCPU_DSISR(r9)
- /* don't overwrite fault_dar/fault_dsisr if HDSI */
- cmpwi r12,BOOK3S_INTERRUPT_H_DATA_STORAGE
- beq mc_cont
- std r6, VCPU_FAULT_DAR(r9)
- stw r7, VCPU_FAULT_DSISR(r9)
-
- /* See if it is a machine check */
- cmpwi r12, BOOK3S_INTERRUPT_MACHINE_CHECK
- beq machine_check_realmode
-mc_cont:
-#ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING
- addi r3, r9, VCPU_TB_RMEXIT
- mr r4, r9
- bl kvmhv_accumulate_time
-#endif
mr r3, r12
/* Increment exit count, poke other threads to exit */