Re: [PATCH v2] Fix SEGFAULT on getting physical address of MMIO region.

[Richard Henderson]

On 8/3/23 03:58, Mikhail Tyutin wrote:
> Apply save_iotlb_data() to io_readx() as well as to io_writex().
>
> Signed-off-by: Dmitriy Solovev <d.solovev@yadro.com>
> Signed-off-by: Mikhail Tyutin <m.tyutin@yadro.com>
> ---
>   accel/tcg/cputlb.c | 36 +++++++++++++++++++++---------------
>   1 file changed, 21 insertions(+), 15 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~

> diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
> index ba44501a7c..addce3be38 100644
> --- a/accel/tcg/cputlb.c
> +++ b/accel/tcg/cputlb.c
> @@ -1363,6 +1363,21 @@ static inline void cpu_transaction_failed(CPUState *cpu, 
> hwaddr physaddr,
>       }
>   }
>   
> +/*
> + * Save a potentially trashed CPUTLBEntryFull for later lookup by plugin.
> + * This is read by tlb_plugin_lookup if the fulltlb entry doesn't match
> + * because of the side effect of io_writex changing memory layout.
> + */
> +static void save_iotlb_data(CPUState *cs, MemoryRegionSection *section,
> +                            hwaddr mr_offset)
> +{
> +#ifdef CONFIG_PLUGIN
> +    SavedIOTLB *saved = &cs->saved_iotlb;
> +    saved->section = section;
> +    saved->mr_offset = mr_offset;
> +#endif
> +}
> +
>   static uint64_t io_readx(CPUArchState *env, CPUTLBEntryFull *full,
>                            int mmu_idx, vaddr addr, uintptr_t retaddr,
>                            MMUAccessType access_type, MemOp op)
> @@ -1382,6 +1397,12 @@ static uint64_t io_readx(CPUArchState *env, 
> CPUTLBEntryFull *full,
>           cpu_io_recompile(cpu, retaddr);
>       }
>   
> +    /*
> +     * The memory_region_dispatch may trigger a flush/resize
> +     * so for plugins we save the iotlb_data just in case.
> +     */
> +    save_iotlb_data(cpu, section, mr_offset);
> +
>       {
>           QEMU_IOTHREAD_LOCK_GUARD();
>           r = memory_region_dispatch_read(mr, mr_offset, &val, op, full->attrs);
> @@ -1398,21 +1419,6 @@ static uint64_t io_readx(CPUArchState *env, 
> CPUTLBEntryFull *full,
>       return val;
>   }
>   
> -/*
> - * Save a potentially trashed CPUTLBEntryFull for later lookup by plugin.
> - * This is read by tlb_plugin_lookup if the fulltlb entry doesn't match
> - * because of the side effect of io_writex changing memory layout.
> - */
> -static void save_iotlb_data(CPUState *cs, MemoryRegionSection *section,
> -                            hwaddr mr_offset)
> -{
> -#ifdef CONFIG_PLUGIN
> -    SavedIOTLB *saved = &cs->saved_iotlb;
> -    saved->section = section;
> -    saved->mr_offset = mr_offset;
> -#endif
> -}
> -
>   static void io_writex(CPUArchState *env, CPUTLBEntryFull *full,
>                         int mmu_idx, uint64_t val, vaddr addr,
>                         uintptr_t retaddr, MemOp op)