Avi Kivity <avi@xxxxxxxxxx> wrote:
> Instead, drop large mappings, which were the reason we dropped shadow.
>
> Signed-off-by: Avi Kivity <avi@xxxxxxxxxx>
> ---
> arch/x86/kvm/mmu.c | 10 ++++++----
> virt/kvm/kvm_main.c | 7 +------
> 2 files changed, 7 insertions(+), 10 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index 43bd5e3..1bbe2c0 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -3444,14 +3444,16 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
> if (!test_bit(slot, sp->slot_bitmap))
> continue;
>
> - if (sp->role.level != PT_PAGE_TABLE_LEVEL)
> - continue;
> -
> pt = sp->spt;
> - for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
> + for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
> + if (sp->role.level != PT_PAGE_TABLE_LEVEL
> + && is_large_pte(pt[i]))
> + drop_spte(kvm, &pt[i],
> + shadow_trap_nonpresent_pte);
> /* avoid RMW */
> if (is_writable_pte(pt[i]))
> update_spte(&pt[i], pt[i] & ~PT_WRITABLE_MASK);
> + }
> }
> kvm_flush_remote_tlbs(kvm);
> }
What is the difference from the similar part in rmap_write_protect()?
=== from rmap_write_protect() ===
/* check for huge page mappings */
for (i = PT_DIRECTORY_LEVEL;
i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
rmapp = gfn_to_rmap(kvm, gfn, i);
spte = rmap_next(kvm, rmapp, NULL);
while (spte) {
BUG_ON(!spte);
BUG_ON(!(*spte & PT_PRESENT_MASK));
BUG_ON((*spte & (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK)) != (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK));
pgprintk("rmap_write_protect(large): spte %p %llx %lld\n", spte, *spte, gfn);
if (is_writable_pte(*spte)) {
drop_spte(kvm, spte,
shadow_trap_nonpresent_pte);
--kvm->stat.lpages;
spte = NULL;
write_protected = 1;
}
spte = rmap_next(kvm, rmapp, spte);
}
}
===
Takuya
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