On Wed, Jul 10, 2024 at 1:30 PM Richard Henderson
<richard.hender...@linaro.org> wrote:
>
> The current pairing of tlb_vaddr_to_host with extra is either
> inefficient (user-only, with page_check_range) or incorrect
> (system, with probe_pages).
>
> For proper non-fault behaviour, use probe_access_flags with
> its nonfault parameter set to true.
>
> Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
Acked-by: Alistair Francis <alistair.fran...@wdc.com>
Alistair
> ---
> target/riscv/vector_helper.c | 34 ++++++++++++++++++----------------
> 1 file changed, 18 insertions(+), 16 deletions(-)
>
> diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c
> index 1b4d5a8e37..4d72eb74d3 100644
> --- a/target/riscv/vector_helper.c
> +++ b/target/riscv/vector_helper.c
> @@ -474,7 +474,6 @@ vext_ldff(void *vd, void *v0, target_ulong base,
> vext_ldst_elem_fn *ldst_elem,
> uint32_t log2_esz, uintptr_t ra)
> {
> - void *host;
> uint32_t i, k, vl = 0;
> uint32_t nf = vext_nf(desc);
> uint32_t vm = vext_vm(desc);
> @@ -493,27 +492,31 @@ vext_ldff(void *vd, void *v0, target_ulong base,
> }
> addr = adjust_addr(env, base + i * (nf << log2_esz));
> if (i == 0) {
> + /* Allow fault on first element. */
> probe_pages(env, addr, nf << log2_esz, ra, MMU_DATA_LOAD);
> } else {
> - /* if it triggers an exception, no need to check watchpoint */
> remain = nf << log2_esz;
> while (remain > 0) {
> + void *host;
> + int flags;
> +
> offset = -(addr | TARGET_PAGE_MASK);
> - host = tlb_vaddr_to_host(env, addr, MMU_DATA_LOAD,
> mmu_index);
> - if (host) {
> -#ifdef CONFIG_USER_ONLY
> - if (!page_check_range(addr, offset, PAGE_READ)) {
> - vl = i;
> - goto ProbeSuccess;
> - }
> -#else
> - probe_pages(env, addr, offset, ra, MMU_DATA_LOAD);
> -#endif
> - } else {
> +
> + /* Probe nonfault on subsequent elements. */
> + flags = probe_access_flags(env, addr, offset, MMU_DATA_LOAD,
> + mmu_index, true, &host, 0);
> + if (flags) {
> + /*
> + * Stop any flag bit set:
> + * invalid (unmapped)
> + * mmio (transaction failed)
> + * watchpoint (debug)
> + * In all cases, handle as the first load next time.
> + */
> vl = i;
> - goto ProbeSuccess;
> + break;
> }
> - if (remain <= offset) {
> + if (remain <= offset) {
> break;
> }
> remain -= offset;
> @@ -521,7 +524,6 @@ vext_ldff(void *vd, void *v0, target_ulong base,
> }
> }
> }
> -ProbeSuccess:
> /* load bytes from guest memory */
> if (vl != 0) {
> env->vl = vl;
> --
> 2.43.0
>
>
