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authorXiao Guangrong <guangrong.xiao@linux.intel.com>2015-04-14 12:04:10 +0800
committerPaolo Bonzini <pbonzini@redhat.com>2015-04-15 17:07:46 +0200
commitdecf63336e356423300b935afbebeca1fcb15184 (patch)
tree31e1b7105d2d91c376338ee65dfdd44c852e5878
parent130005231c9f2090b1b177e2cca9841b562c1784 (diff)
downloadlinux-decf63336e356423300b935afbebeca1fcb15184.tar.bz2
KVM: MMU: fix comment in kvm_mmu_zap_collapsible_spte
Soft mmu uses direct shadow page to fill guest large mapping with small pages if huge mapping is disallowed on host. So zapping direct shadow page works well both for soft mmu and hard mmu, it's just less widely applicable. Fix the comment to reflect this. Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> Message-Id: <552C91BA.1010703@linux.intel.com> [Fix comment wording further. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--arch/x86/kvm/mmu.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 07bb22157338..d43867c33bc4 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -4481,9 +4481,11 @@ static bool kvm_mmu_zap_collapsible_spte(struct kvm *kvm,
pfn = spte_to_pfn(*sptep);
/*
- * Only EPT supported for now; otherwise, one would need to
- * find out efficiently whether the guest page tables are
- * also using huge pages.
+ * We cannot do huge page mapping for indirect shadow pages,
+ * which are found on the last rmap (level = 1) when not using
+ * tdp; such shadow pages are synced with the page table in
+ * the guest, and the guest page table is using 4K page size
+ * mapping if the indirect sp has level = 1.
*/
if (sp->role.direct &&
!kvm_is_reserved_pfn(pfn) &&