Re: [PATCH v3 24/39] xen/riscv: add guest load emulation for trapped MMIO accesses

[Baptiste Le Duc <baptiste.le-duc@xxxxxxxxxx>]

On 2026-10-15 16:59:53+02:00, Oleksii Kurochko wrote:
> On 9/30/26 6:23 PM, Oleksii Kurochko wrote:
> 
> > Implement emulate_load() on top of the decoding interface introduced by
> > the previous patch: fetch the trapped instruction, decode it, dispatch
> > the access to a registered MMIO handler via do_mmio(), write the result
> > back into the destination register and step over the instruction.
> > 
> > Xen dispatches MMIO synchronously to an in-hypervisor handler, so unlike
> > KVM RISC-V there is no userspace exit/return step and no equivalent of
> > the kvm_io_bus_read() / KVM_EXIT_MMIO / kvm_riscv_vcpu_mmio_return()
> > split; the result is consumed in place.
> > 
> > Sign extension is done here rather than in the handlers: a signed load
> > is normalized by a shift pair, so a handler need only report the value
> > it read.
> 
> This part of commit message should be updated. Suggestion look below...
> 
> > At the moment vINTC is the only backend registered with the MMIO
> > dispatch, so in practice this only covers vINTC traps. An access which
> > no handler claims currently crashes the domain; injecting an access
> > fault into the guest instead is left for later.
> > 
> > Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
> > ---
> 
> [...]
Sorry I don't understand, did you forget to put the suggestion?

-- 
Baptiste Le Duc <baptiste.le-duc@xxxxxxxxxx>