KVM: PPC: e500mc: Add support for single threaded vcpus on e6500 core

ePAPR represents hardware threads as cpu node properties in device tree.
So with existing QEMU, hardware threads are simply exposed as vcpus with
one hardware thread.

The e6500 core shares TLBs between hardware threads. Without tlb write
conditional instruction, the Linux kernel uses per core mechanisms to
protect against duplicate TLB entries.

The guest is unable to detect real siblings threads, so it can't use the
TLB protection mechanism. An alternative solution is to use the hypervisor
to allocate different lpids to guest's vcpus that runs simultaneous on real
siblings threads. On systems with two threads per core this patch halves
the size of the lpid pool that the allocator sees and use two lpids per VM.
Use even numbers to speedup vcpu lpid computation with consecutive lpids
per VM: vm1 will use lpids 2 and 3, vm2 lpids 4 and 5, and so on.

Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
[agraf: fix spelling]
Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 8 insertions, 10 deletions

diff --git a/arch/powerpc/kvm/e500_mmu_host.c b/arch/powerpc/kvm/e500_mmu_host.c
index 08f14bb57897..c8795a64e935 100644
--- a/arch/powerpc/kvm/e500_mmu_host.c
+++ b/arch/powerpc/kvm/e500_mmu_host.c
@@ -69,7 +69,8 @@ static inline u32 e500_shadow_mas3_attrib(u32 mas3, int usermode)
  * writing shadow tlb entry to host TLB
  */
 static inline void __write_host_tlbe(struct kvm_book3e_206_tlb_entry *stlbe,
-                                     uint32_t mas0)
+                                     uint32_t mas0,
+                                     uint32_t lpid)
 {
         unsigned long flags;
 
@@ -80,7 +81,7 @@ static inline void __write_host_tlbe(struct kvm_book3e_206_tlb_entry *stlbe,
         mtspr(SPRN_MAS3, (u32)stlbe->mas7_3);
         mtspr(SPRN_MAS7, (u32)(stlbe->mas7_3 >> 32));
 #ifdef CONFIG_KVM_BOOKE_HV
-        mtspr(SPRN_MAS8, stlbe->mas8);
+        mtspr(SPRN_MAS8, MAS8_TGS | get_thread_specific_lpid(lpid));
 #endif
         asm volatile("isync; tlbwe" : : : "memory");
 
@@ -129,11 +130,12 @@ static inline void write_host_tlbe(struct kvmppc_vcpu_e500 *vcpu_e500,
 
         if (tlbsel == 0) {
                 mas0 = get_host_mas0(stlbe->mas2);
-                __write_host_tlbe(stlbe, mas0);
+                __write_host_tlbe(stlbe, mas0, vcpu_e500->vcpu.kvm->arch.lpid);
         } else {
                 __write_host_tlbe(stlbe,
                                   MAS0_TLBSEL(1) |
-                                  MAS0_ESEL(to_htlb1_esel(sesel)));
+                                  MAS0_ESEL(to_htlb1_esel(sesel)),
+                                  vcpu_e500->vcpu.kvm->arch.lpid);
         }
 }
 
@@ -176,7 +178,7 @@ void kvmppc_map_magic(struct kvm_vcpu *vcpu)
                        MAS3_SW | MAS3_SR | MAS3_UW | MAS3_UR;
         magic.mas8 = 0;
 
-        __write_host_tlbe(&magic, MAS0_TLBSEL(1) | MAS0_ESEL(tlbcam_index));
+        __write_host_tlbe(&magic, MAS0_TLBSEL(1) | MAS0_ESEL(tlbcam_index), 0);
         preempt_enable();
 }
 #endif
@@ -317,10 +319,6 @@ static void kvmppc_e500_setup_stlbe(
         stlbe->mas2 = (gvaddr & MAS2_EPN) | (ref->flags & E500_TLB_MAS2_ATTR);
         stlbe->mas7_3 = ((u64)pfn << PAGE_SHIFT) |
                         e500_shadow_mas3_attrib(gtlbe->mas7_3, pr);
-
-#ifdef CONFIG_KVM_BOOKE_HV
-        stlbe->mas8 = MAS8_TGS | vcpu->kvm->arch.lpid;
-#endif
 }
 
 static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
@@ -633,7 +631,7 @@ int kvmppc_load_last_inst(struct kvm_vcpu *vcpu, enum instruction_type type,
 
         local_irq_save(flags);
         mtspr(SPRN_MAS6, (vcpu->arch.pid << MAS6_SPID_SHIFT) | addr_space);
-        mtspr(SPRN_MAS5, MAS5_SGS | vcpu->kvm->arch.lpid);
+        mtspr(SPRN_MAS5, MAS5_SGS | get_lpid(vcpu));
         asm volatile("tlbsx 0, %[geaddr]\n" : :
                      [geaddr] "r" (geaddr));
         mtspr(SPRN_MAS5, 0);