hw/cpu: Extend CPUState::cluster_index documentation

Copy part of the description of commit f7b78602fd ("accel/tcg:
Add cluster number to TCG TB hash") in tcg_cpu_init_cflags(),
improving a bit CPUState::cluster_index documentation.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20230216142338.82982-2-philmd@linaro.org>
This commit is contained in:
Philippe Mathieu-Daudé 2023-02-16 10:09:48 +01:00
parent 2d2f2507c6
commit a371975ef6
2 changed files with 14 additions and 1 deletions

View File

@ -44,7 +44,18 @@
void tcg_cpu_init_cflags(CPUState *cpu, bool parallel)
{
uint32_t cflags = cpu->cluster_index << CF_CLUSTER_SHIFT;
uint32_t cflags;
/*
* 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).
*/
cflags = cpu->cluster_index << CF_CLUSTER_SHIFT;
cflags |= parallel ? CF_PARALLEL : 0;
cflags |= icount_enabled() ? CF_USE_ICOUNT : 0;
cpu->tcg_cflags = cflags;

View File

@ -272,6 +272,8 @@ struct qemu_work_item;
* to a cluster this will be UNASSIGNED_CLUSTER_INDEX; otherwise it will
* be the same as the cluster-id property of the CPU object's TYPE_CPU_CLUSTER
* QOM parent.
* Under TCG this value is propagated to @tcg_cflags.
* See TranslationBlock::TCG CF_CLUSTER_MASK.
* @tcg_cflags: Pre-computed cflags for this cpu.
* @nr_cores: Number of cores within this CPU package.
* @nr_threads: Number of threads within this CPU.