[Qemu-devel] [PATCH 4/4] target/arm: Install ASIDs for EL2

[Richard Henderson <richard.henderson@linaro.org>]

The VMID is the ASID for the 2nd stage page lookup.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/helper.c | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/target/arm/helper.c b/target/arm/helper.c
index f767467dcf..4b14f2c05b 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -2805,17 +2805,23 @@ static void vmsa_ttbr_el1_write(CPUARMState *env, const ARMCPRegInfo *ri,
 static void vttbr_write(CPUARMState *env, const ARMCPRegInfo *ri,
                         uint64_t value)
 {
-    ARMCPU *cpu = arm_env_get_cpu(env);
-    CPUState *cs = CPU(cpu);
+    CPUState *cs = CPU(arm_env_get_cpu(env));
+    int vmid;
 
-    /* Accesses to VTTBR may change the VMID so we must flush the TLB.  */
-    if (raw_read(env, ri) != value) {
-        tlb_flush_by_mmuidx(cs,
-                            ARMMMUIdxBit_S12NSE1 |
-                            ARMMMUIdxBit_S12NSE0 |
-                            ARMMMUIdxBit_S2NS);
-        raw_write(env, ri, value);
-    }
+    raw_write(env, ri, value);
+
+    /*
+     * TODO: with ARMv8.1-VMID16, aarch64 must examine VTCR.VS
+     * (re-evaluating with changes to VTCR) then use bits [63:48].
+     */
+    vmid = extract64(value, 48, 8);
+
+    /*
+     * A change in VMID to the stage2 page table (S2NS) invalidates
+     * the combined stage 1&2 tlbs (S12NSE1 and S12NSE0).
+     */
+    tlb_set_asid_for_mmuidx(cs, vmid, ARMMMUIdxBit_S2NS,
+                            ARMMMUIdxBit_S12NSE1 | ARMMMUIdxBit_S12NSE0);
 }
 
 static const ARMCPRegInfo vmsa_pmsa_cp_reginfo[] = {
-- 
2.17.2