On Tue, Jul 18, 2023 at 4:49 PM Sean Christopherson <seanjc@xxxxxxxxxx> wrote:
> ...
> +static int kvm_gmem_error_page(struct address_space *mapping, struct page *page)
> +{
> + struct list_head *gmem_list = &mapping->private_list;
> + struct kvm_memory_slot *slot;
> + struct kvm_gmem *gmem;
> + unsigned long index;
> + pgoff_t start, end;
> + gfn_t gfn;
> +
> + filemap_invalidate_lock_shared(mapping);
> +
> + start = page->index;
> + end = start + thp_nr_pages(page);
> +
> + list_for_each_entry(gmem, gmem_list, entry) {
> + xa_for_each_range(&gmem->bindings, index, slot, start, end - 1) {
> + for (gfn = start; gfn < end; gfn++) {
> + if (WARN_ON_ONCE(gfn < slot->base_gfn ||
> + gfn >= slot->base_gfn + slot->npages))
> + continue;
> +
> + /*
> + * FIXME: Tell userspace that the *private*
> + * memory encountered an error.
> + */
> + send_sig_mceerr(BUS_MCEERR_AR,
> + (void __user *)gfn_to_hva_memslot(slot, gfn),
> + PAGE_SHIFT, current);
Does it make sense to replicate what happens with MCE handling on
tmpfs backed guest memory:
1) Unmap gpa from guest
2) On the next guest EPT fault, exit to userspace to handle/log the
mce error for the gpa.
IIUC, such MCEs could be asynchronous and "current" might not always
be the intended recipient of this signal.
> + }
> + }
> + }
> +
> + filemap_invalidate_unlock_shared(mapping);
> +
> + return 0;
> +}
> +
