On Tue, 16 Feb 2021 at 14:39, 沈梦姣 <shen.mengji...@icloud.com> wrote: > > 在 2021年2月16日，下午7:48，Peter Maydell <peter.mayd...@linaro.org> 写道： > > > > On Tue, 16 Feb 2021 at 11:28, 沈梦姣 <shen.mengji...@icloud.com> wrote: > >> Look at the store/load helper, it will use the tlb entry to do the address > >> translation(from guest virtual address to host virtual address) but where > >> the tlb is filled for the data ram and io address, I know where the code > >> ram is filled(tb_find->tb_lookup__cpu_state...) > > > > The common QEMU code calls the target > Thanks Peter. But what’s the common code? I mean in which case the tlb_fill > will be triggered, the generated code will trigger or something else? Thanks > in advance.
"git grep tlb_fill accel/tcg" will tell you the call sites. Basically if the guest code tries to access an address and we don't already have that in the QEMU TLB, then we call tlb_fill. > > CPU tlb_fill function, which tries > > to translate the guest virtual address to a physical address (usually by > > walking the guest page tables). If it succeeds then will update the QEMU > > TLB by calling either tlb_set_page() or tlb_set_page_with_attrs(). > > > If it > > fails then it arranges to deliver a suitable exception to the guest. > This should be page fault, guest code will update page table, am I right? > Thanks It depends on the guest architecture, but yes, that's the usual thing. -- PMM
