| Message ID | 20180517044849.GB31160@fergus.ozlabs.ibm.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | KVM: PPC: Book 3S HV: Do ptesync in radix guest exit path | expand |
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index bd63fa8..122726b 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -1905,6 +1905,14 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300) cmpwi cr2, r0, 0 beq cr2, 4f + /* + * Radix: do eieio; tlbsync; ptesync sequence in case we + * interrupted the guest between a tlbie and a ptesync. + */ + eieio + tlbsync + ptesync + /* Radix: Handle the case where the guest used an illegal PID */ LOAD_REG_ADDR(r4, mmu_base_pid) lwz r3, VCPU_GUEST_PID(r9)
A radix guest can execute tlbie instructions to invalidate TLB entries. After a tlbie or a group of tlbies, it must then do the architected sequence eieio; tlbsync; ptesync to ensure that the TLB invalidation has been processed by all CPUs in the system before it can rely on no CPU using any translation that it just invalidated. In fact it is the ptesync which does the actual synchronization in this sequence, and hardware has a requirement that the ptesync must be executed on the same CPU thread as the tlbies which it is expected to order. Thus, if a vCPU gets moved from one physical CPU to another after it has done some tlbies but before it can get to do the ptesync, the ptesync will not have the desired effect when it is executed on the second physical CPU. To fix this, we do a ptesync in the exit path for radix guests. If there are any pending tlbies, this will wait for them to complete. If there aren't, then ptesync will just do the same as sync. Signed-off-by: Paul Mackerras <paulus@ozlabs.org> --- arch/powerpc/kvm/book3s_hv_rmhandlers.S | 8 ++++++++ 1 file changed, 8 insertions(+)