Joerg Roedel wrote:
+static int has_wrprotected_largepage(struct kvm *kvm, gfn_t gfn)
+{
+ struct kvm_memory_slot *slot;
+ int *hugepage_idx;
+
+ gfn = unalias_gfn(kvm, gfn);
+ slot = gfn_to_memslot_unaliased(kvm, gfn);
+ if (slot) {
+ hugepage_idx = slot_hugepage_idx(gfn, slot);
slot_largepage_idx() here?
I don't think we ever write protect large pages, so why is this needed?
For 2mb pages we need to check if there is a write-protected 4k page in it
before we map a 2mb page for writing. If there is any write-protected 4k
page in a 2mb area this 2mb page is considered write-protected. These
'write-protected' 2mb pages are accounted in the account_shadow()
function. This information is taken into account when we decide if we
can map a guest 1gb page as a 1gb page on the host too.
account_shadowed() actually increments a hugepage write_count by 1 for
every 4K page, not 2M page, if I read the code correctly. The code I
commented on is right though.
The naming is confusing. I suggest
has_wrprotected_page_in_{large,huge}page(). although with the a level
parameter we can keep has_wrprotected_page().
btw, if we implement account_shadow() as you describe it (only account
hugepages on largepage transition 0->1 or 1->0) we save a potential
cacheline bounce on the hugepage write_count accounting array.
--
error compiling committee.c: too many arguments to function
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
