tcg: Use tlb_fill probe from tlb_vaddr_to_host

Most of the existing users would continue around a loop which
would fault the tlb entry in via a normal load/store.

But for AArch64 SVE we have an existing emulation bug wherein we
would mark the first element of a no-fault vector load as faulted
(within the FFR, not via exception) just because we did not have
its address in the TLB.  Now we can properly only mark it as faulted
if there really is no valid, readable translation, while still not
raising an exception.  (Note that beyond the first element of the
vector, the hardware may report a fault for any reason whatsoever;
with at least one element loaded, forward progress is guaranteed.)

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 1 insertions, 5 deletions

diff --git a/target/arm/sve_helper.c b/target/arm/sve_helper.c
index bc84725..fd434c6 100644
--- a/target/arm/sve_helper.c
+++ b/target/arm/sve_helper.c
@@ -4598,11 +4598,7 @@ static void sve_ldnf1_r(CPUARMState *env, void *vg, const target_ulong addr,
      * in the real world, obviously.)
      *
      * Then there are the annoying special cases with watchpoints...
-     *
-     * TODO: Add a form of tlb_fill that does not raise an exception,
-     * with a form of tlb_vaddr_to_host and a set of loads to match.
-     * The non_fault_vaddr_to_host would handle everything, usually,
-     * and the loads would handle the iomem path for watchpoints.
+     * TODO: Add a form of non-faulting loads using cc->tlb_fill(probe=true).
      */
     host = tlb_vaddr_to_host(env, addr + mem_off, MMU_DATA_LOAD, mmu_idx);
     split = max_for_page(addr, mem_off, mem_max);