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From: Richard Henderson <rth@twiddle.net>
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Date: Thu, 8 Sep 2016 10:23:51 -0700
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Subject: Re: [Qemu-devel] [RFC v4 25/28] cputlb: introduce tlb_flush_* async
 work.
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To: =?UTF-8?Q?Alex_Benn=c3=a9e?= <alex.bennee@linaro.org>, mttcg@greensocs.com, qemu-devel@nongnu.org, fred.konrad@greensocs.com, a.rigo@virtualopensystems.com, cota@braap.org, bobby.prani@gmail.com, nikunj@linux.vnet.ibm.com
Cc: peter.maydell@linaro.org, claudio.fontana@huawei.com, Peter Crosthwaite <crosthwaite.peter@gmail.com>, jan.kiszka@siemens.com, mark.burton@greensocs.com, serge.fdrv@gmail.com, pbonzini@redhat.com

On 08/11/2016 08:24 AM, Alex Bennée wrote:
> + * Since QEMU doesn't currently implement a global/not-global flag
> + * for tlb entries, at the moment tlb_flush() will also flush all
> + * tlb entries in the flush_global == false case. This is OK because
> + * CPU architectures generally permit an implementation to drop
> + * entries from the TLB at any time, so flushing more entries than
> + * required is only an efficiency issue, not a correctness issue.
> + */
> +void tlb_flush(CPUState *cpu, int flush_global)
> +{
> +    if (cpu->created && !qemu_cpu_is_self(cpu)) {
> +        if (atomic_bool_cmpxchg(&cpu->pending_tlb_flush, false, true)) {
> +            async_run_on_cpu(cpu, tlb_flush_global_async_work,
> +                             GINT_TO_POINTER(flush_global));

Given that we don't actually do anything with flush_global, let's not work so
hard to pass it down.  Especially with something as ugly as GINT_TO_POINTER.

Or indeed, as a cleanup, remove that argument from all callers.  If we want to
retain the documentation for the targets, we could do

#define tlb_flush_local   tlb_flush
#define tlb_flush_global  tlb_flush


r~