4.14-stable review patch. If anyone has any objections, please let me know.
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From: Paul Mackerras paulus@ozlabs.org
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@ozlabs.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- 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 */