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Re: [Qemu-devel] [PATCH 1/2] cputlb: Use memset when flushing entries
From: |
Aurelien Jarno |
Subject: |
Re: [Qemu-devel] [PATCH 1/2] cputlb: Use memset when flushing entries |
Date: |
Sun, 22 Dec 2013 19:04:48 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Sat, Dec 07, 2013 at 10:44:51AM +1300, Richard Henderson wrote:
> The size of tlb_table is 4k on a 64-bit host. For overwriting
> memory at this size, cacheline tricks can help.
>
> Signed-off-by: Richard Henderson <address@hidden>
> ---
> cputlb.c | 19 ++-----------------
> 1 file changed, 2 insertions(+), 17 deletions(-)
>
> diff --git a/cputlb.c b/cputlb.c
> index fff0afb..d2da404 100644
> --- a/cputlb.c
> +++ b/cputlb.c
> @@ -33,13 +33,6 @@
> /* statistics */
> int tlb_flush_count;
>
> -static const CPUTLBEntry s_cputlb_empty_entry = {
> - .addr_read = -1,
> - .addr_write = -1,
> - .addr_code = -1,
> - .addend = -1,
> -};
> -
> /* NOTE:
> * If flush_global is true (the usual case), flush all tlb entries.
> * If flush_global is false, flush (at least) all tlb entries not
> @@ -55,7 +48,6 @@ static const CPUTLBEntry s_cputlb_empty_entry = {
> void tlb_flush(CPUArchState *env, int flush_global)
> {
> CPUState *cpu = ENV_GET_CPU(env);
> - int i;
>
> #if defined(DEBUG_TLB)
> printf("tlb_flush:\n");
> @@ -64,14 +56,7 @@ void tlb_flush(CPUArchState *env, int flush_global)
> links while we are modifying them */
> cpu->current_tb = NULL;
>
> - for (i = 0; i < CPU_TLB_SIZE; i++) {
> - int mmu_idx;
> -
> - for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
> - env->tlb_table[mmu_idx][i] = s_cputlb_empty_entry;
> - }
> - }
> -
> + memset(env->tlb_table, -1, sizeof(env->tlb_table));
> memset(env->tb_jmp_cache, 0, TB_JMP_CACHE_SIZE * sizeof (void *));
>
> env->tlb_flush_addr = -1;
> @@ -87,7 +72,7 @@ static inline void tlb_flush_entry(CPUTLBEntry *tlb_entry,
> target_ulong addr)
> (TARGET_PAGE_MASK | TLB_INVALID_MASK)) ||
> addr == (tlb_entry->addr_code &
> (TARGET_PAGE_MASK | TLB_INVALID_MASK))) {
> - *tlb_entry = s_cputlb_empty_entry;
> + memset(tlb_entry, -1, sizeof(*tlb_entry));
> }
> }
Reviewed-by: Aurelien Jarno <address@hidden>
--
Aurelien Jarno GPG: 1024D/F1BCDB73
address@hidden http://www.aurel32.net