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Re: [Qemu-devel] [PATCH 3/4] accel/tcg: Add cluster number to TCG TB has
From: |
Luc Michel |
Subject: |
Re: [Qemu-devel] [PATCH 3/4] accel/tcg: Add cluster number to TCG TB hash |
Date: |
Thu, 10 Jan 2019 16:14:46 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.3 |
On 1/8/19 5:30 PM, Peter Maydell wrote:
> Include the cluster number in the hash we use to look
> up TBs. This is important because a TB that is valid
> for one cluster at a given physical address and set
> of CPU flags is not necessarily valid for another:
> the two clusters may have different views of physical
> memory, or may have different CPU features (eg FPU
> present or absent).
>
> We put the cluster number in the high 8 bits of the
> TB cflags. This gives us up to 256 clusters, which should
> be enough for anybody. If we ever need more, or need
> more bits in cflags for other purposes, we could make
> tb_hash_func() take more data (and expand qemu_xxhash7()
> to qemu_xxhash8()).
>
> Signed-off-by: Peter Maydell <address@hidden>
Reviewed-by: Luc Michel <address@hidden>
> ---
> include/exec/exec-all.h | 4 +++-
> accel/tcg/cpu-exec.c | 4 ++++
> accel/tcg/translate-all.c | 3 +++
> 3 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
> index 815e5b1e838..aa7b81aaf01 100644
> --- a/include/exec/exec-all.h
> +++ b/include/exec/exec-all.h
> @@ -351,9 +351,11 @@ struct TranslationBlock {
> #define CF_USE_ICOUNT 0x00020000
> #define CF_INVALID 0x00040000 /* TB is stale. Set with @jmp_lock held */
> #define CF_PARALLEL 0x00080000 /* Generate code for a parallel context */
> +#define CF_CLUSTER_MASK 0xff000000 /* Top 8 bits are cluster ID */
> +#define CF_CLUSTER_SHIFT 24
> /* cflags' mask for hashing/comparison */
> #define CF_HASH_MASK \
> - (CF_COUNT_MASK | CF_LAST_IO | CF_USE_ICOUNT | CF_PARALLEL)
> + (CF_COUNT_MASK | CF_LAST_IO | CF_USE_ICOUNT | CF_PARALLEL |
> CF_CLUSTER_MASK)
>
> /* Per-vCPU dynamic tracing state used to generate this TB */
> uint32_t trace_vcpu_dstate;
> diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
> index 870027d4359..e578a1a3aee 100644
> --- a/accel/tcg/cpu-exec.c
> +++ b/accel/tcg/cpu-exec.c
> @@ -336,6 +336,10 @@ TranslationBlock *tb_htable_lookup(CPUState *cpu,
> target_ulong pc,
> return NULL;
> }
> desc.phys_page1 = phys_pc & TARGET_PAGE_MASK;
> +
> + cf_mask &= ~CF_CLUSTER_MASK;
> + cf_mask |= cpu->cluster_index << CF_CLUSTER_SHIFT;
> +
> h = tb_hash_func(phys_pc, pc, flags, cf_mask, *cpu->trace_dstate);
> return qht_lookup_custom(&tb_ctx.htable, &desc, h, tb_lookup_cmp);
> }
> diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
> index 639f0b27287..ba27f5acc8c 100644
> --- a/accel/tcg/translate-all.c
> +++ b/accel/tcg/translate-all.c
> @@ -1692,6 +1692,9 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
> cflags |= CF_NOCACHE | 1;
> }
>
> + cflags &= ~CF_CLUSTER_MASK;
> + cflags |= cpu->cluster_index << CF_CLUSTER_SHIFT;
> +
> buffer_overflow:
> tb = tb_alloc(pc);
> if (unlikely(!tb)) {
>
[Qemu-devel] [PATCH 4/4] gdbstub: Simplify gdb_get_cpu_pid() to use cpu->cluster_index, Peter Maydell, 2019/01/08
Re: [Qemu-devel] [PATCH 0/4] tcg: support heterogenous CPU clusters, Richard Henderson, 2019/01/09