[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [RFC PATCH] xtensa: Avoid calling get_page_addr_code()
Re: [Qemu-devel] [RFC PATCH] xtensa: Avoid calling get_page_addr_code() from helper function
Sat, 30 Jun 2018 10:32:15 -0700
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0
On 06/22/2018 06:58 AM, Peter Maydell wrote:
> The xtensa frontend calls get_page_addr_code() from its
> itlb_hit_test helper function. This function is really part
> of the TCG core's internals, and calling it from a target
> helper makes it awkward to make changes to that core code.
> It also means that we don't pass the correct retaddr to
> tlb_fill(), so we won't correctly handle the case where
> an exception is generated.
> The helper is used for the instructions IHI, IHU and IPFL.
I think the implementation of these instructions is completely wrong.
(1a) IHI is not invalidating the cacheline within env->config->itlb,
(1b) IHI is not invalidating the qemu TLB that might contain a copy
(2a) IPFL is not locking the entry in env->config->itlb,
(2b) IHU is not unlocking the same entry.
(2c) "Xtensa ISA implementations that do not implement cache locking
must raise an illegal instruction exception when [IPFL or IHU]