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Re: [Qemu-devel] Tracing guest virtual addresses
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] Tracing guest virtual addresses |
Date: |
Mon, 26 Jun 2017 13:14:52 +0100 |
On 26 June 2017 at 13:04, Lluís Vilanova <address@hidden> wrote:
> Peter Maydell writes:
>
>> On 26 June 2017 at 10:26, Lluís Vilanova <address@hidden> wrote:
>>> There's two places where memory access tracing is triggered:
>>>
>>> * tcg_gen_qemu_ld/st_...
>>> * ld/st templates (both softmmu and user)
>>>
>>> AFAIK, helpers use the ld/st templates to access guest memory.
>
>> Mostly, but there are one or two special cases, for instance
>> the ARM HELPER(dc_zva) in target/arm/helper.c, which has a
>> fastpath that uses tlb_vaddr_to_host to look up the host memory
>> address and then memset to do the clear-to-zeroes operation.
>
> Should that be replaced with a cpu_memset or similar?
Possibly -- PPC and S390 also have a fast-memset like this
(and S390 also has a fast-memmove). However I would be wary
of there being architecture-specific corner cases (eg
needing to get the right vaddr for a fault if the accesses
fault).
thanks
-- PMM
- [Qemu-devel] Tracing guest virtual addresses, Jayanto Minocha, 2017/06/19
- Re: [Qemu-devel] Tracing guest virtual addresses, Lluís Vilanova, 2017/06/20
- Re: [Qemu-devel] Tracing guest virtual addresses, Peter Maydell, 2017/06/20
- Re: [Qemu-devel] Tracing guest virtual addresses, Alex Bennée, 2017/06/21
- Re: [Qemu-devel] Tracing guest virtual addresses, Lluís Vilanova, 2017/06/25
- Re: [Qemu-devel] Tracing guest virtual addresses, Alex Bennée, 2017/06/25
- Re: [Qemu-devel] Tracing guest virtual addresses, Lluís Vilanova, 2017/06/26
- Re: [Qemu-devel] Tracing guest virtual addresses, Peter Maydell, 2017/06/26
- Re: [Qemu-devel] Tracing guest virtual addresses, Lluís Vilanova, 2017/06/26
- Re: [Qemu-devel] Tracing guest virtual addresses,
Peter Maydell <=
Re: [Qemu-devel] Tracing guest virtual addresses, Emilio G. Cota, 2017/06/20