cputlb: introduce tlb_flush_*_all_cpus[_synced]

This introduces support to the cputlb API for flushing all CPUs TLBs
with one call. This avoids the need for target helpers to iterate
through the vCPUs themselves.

An additional variant of the API (_synced) will cause the source vCPUs
work to be scheduled as "safe work". The result will be all the flush
operations will be complete by the time the originating vCPU executes
its safe work. The calling implementation can either end the TB
straight away (which will then pick up the cpu->exit_request on
entering the next block) or defer the exit until the architectural
sync point (usually a barrier instruction).

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>

1 files changed, 102 insertions, 6 deletions

diff --git a/cputlb.c b/cputlb.c
index 65003350e3..7fa7fefa05 100644
--- a/cputlb.c
+++ b/cputlb.c
@@ -73,6 +73,25 @@ QEMU_BUILD_BUG_ON(sizeof(target_ulong) > sizeof(run_on_cpu_data));
 QEMU_BUILD_BUG_ON(NB_MMU_MODES > 16);
 #define ALL_MMUIDX_BITS ((1 << NB_MMU_MODES) - 1)
 
+/* flush_all_helper: run fn across all cpus
+ *
+ * If the wait flag is set then the src cpu's helper will be queued as
+ * "safe" work and the loop exited creating a synchronisation point
+ * where all queued work will be finished before execution starts
+ * again.
+ */
+static void flush_all_helper(CPUState *src, run_on_cpu_func fn,
+                             run_on_cpu_data d)
+{
+    CPUState *cpu;
+
+    CPU_FOREACH(cpu) {
+        if (cpu != src) {
+            async_run_on_cpu(cpu, fn, d);
+        }
+    }
+}
+
 /* statistics */
 int tlb_flush_count;
 
@@ -128,6 +147,20 @@ void tlb_flush(CPUState *cpu)
     }
 }
 
+void tlb_flush_all_cpus(CPUState *src_cpu)
+{
+    const run_on_cpu_func fn = tlb_flush_global_async_work;
+    flush_all_helper(src_cpu, fn, RUN_ON_CPU_NULL);
+    fn(src_cpu, RUN_ON_CPU_NULL);
+}
+
+void tlb_flush_all_cpus_synced(CPUState *src_cpu)
+{
+    const run_on_cpu_func fn = tlb_flush_global_async_work;
+    flush_all_helper(src_cpu, fn, RUN_ON_CPU_NULL);
+    async_safe_run_on_cpu(src_cpu, fn, RUN_ON_CPU_NULL);
+}
+
 static void tlb_flush_by_mmuidx_async_work(CPUState *cpu, run_on_cpu_data data)
 {
     CPUArchState *env = cpu->env_ptr;
@@ -178,6 +211,29 @@ void tlb_flush_by_mmuidx(CPUState *cpu, uint16_t idxmap)
     }
 }
 
+void tlb_flush_by_mmuidx_all_cpus(CPUState *src_cpu, uint16_t idxmap)
+{
+    const run_on_cpu_func fn = tlb_flush_by_mmuidx_async_work;
+
+    tlb_debug("mmu_idx: 0x%"PRIx16"\n", idxmap);
+
+    flush_all_helper(src_cpu, fn, RUN_ON_CPU_HOST_INT(idxmap));
+    fn(src_cpu, RUN_ON_CPU_HOST_INT(idxmap));
+}
+
+void tlb_flush_by_mmuidx_all_cpus_synced(CPUState *src_cpu,
+                                                       uint16_t idxmap)
+{
+    const run_on_cpu_func fn = tlb_flush_by_mmuidx_async_work;
+
+    tlb_debug("mmu_idx: 0x%"PRIx16"\n", idxmap);
+
+    flush_all_helper(src_cpu, fn, RUN_ON_CPU_HOST_INT(idxmap));
+    async_safe_run_on_cpu(src_cpu, fn, RUN_ON_CPU_HOST_INT(idxmap));
+}
+
+
+
 static inline void tlb_flush_entry(CPUTLBEntry *tlb_entry, target_ulong addr)
 {
     if (addr == (tlb_entry->addr_read &
@@ -317,14 +373,54 @@ void tlb_flush_page_by_mmuidx(CPUState *cpu, target_ulong addr, uint16_t idxmap)
     }
 }
 
-void tlb_flush_page_all(target_ulong addr)
+void tlb_flush_page_by_mmuidx_all_cpus(CPUState *src_cpu, target_ulong addr,
+                                       uint16_t idxmap)
 {
-    CPUState *cpu;
+    const run_on_cpu_func fn = tlb_check_page_and_flush_by_mmuidx_async_work;
+    target_ulong addr_and_mmu_idx;
 
-    CPU_FOREACH(cpu) {
-        async_run_on_cpu(cpu, tlb_flush_page_async_work,
-                         RUN_ON_CPU_TARGET_PTR(addr));
-    }
+    tlb_debug("addr: "TARGET_FMT_lx" mmu_idx:%"PRIx16"\n", addr, idxmap);
+
+    /* This should already be page aligned */
+    addr_and_mmu_idx = addr & TARGET_PAGE_MASK;
+    addr_and_mmu_idx |= idxmap;
+
+    flush_all_helper(src_cpu, fn, RUN_ON_CPU_TARGET_PTR(addr_and_mmu_idx));
+    fn(src_cpu, RUN_ON_CPU_TARGET_PTR(addr_and_mmu_idx));
+}
+
+void tlb_flush_page_by_mmuidx_all_cpus_synced(CPUState *src_cpu,
+                                                            target_ulong addr,
+                                                            uint16_t idxmap)
+{
+    const run_on_cpu_func fn = tlb_check_page_and_flush_by_mmuidx_async_work;
+    target_ulong addr_and_mmu_idx;
+
+    tlb_debug("addr: "TARGET_FMT_lx" mmu_idx:%"PRIx16"\n", addr, idxmap);
+
+    /* This should already be page aligned */
+    addr_and_mmu_idx = addr & TARGET_PAGE_MASK;
+    addr_and_mmu_idx |= idxmap;
+
+    flush_all_helper(src_cpu, fn, RUN_ON_CPU_TARGET_PTR(addr_and_mmu_idx));
+    async_safe_run_on_cpu(src_cpu, fn, RUN_ON_CPU_TARGET_PTR(addr_and_mmu_idx));
+}
+
+void tlb_flush_page_all_cpus(CPUState *src, target_ulong addr)
+{
+    const run_on_cpu_func fn = tlb_flush_page_async_work;
+
+    flush_all_helper(src, fn, RUN_ON_CPU_TARGET_PTR(addr));
+    fn(src, RUN_ON_CPU_TARGET_PTR(addr));
+}
+
+void tlb_flush_page_all_cpus_synced(CPUState *src,
+                                                  target_ulong addr)
+{
+    const run_on_cpu_func fn = tlb_flush_page_async_work;
+
+    flush_all_helper(src, fn, RUN_ON_CPU_TARGET_PTR(addr));
+    async_safe_run_on_cpu(src, fn, RUN_ON_CPU_TARGET_PTR(addr));
 }
 
 /* update the TLBs so that writes to code in the virtual page 'addr'