mmu_try_to_unsync_pages() performs !can_unsync check before attempting
to unsync any shadow pages.
This check is peformed inside the loop right now.
It's redundant to perform it every iteration if can_unsync is true, as
can_unsync parameter isn't getting updated inside the loop.
Move the check outside of the loop.
Same is the case with prefetch.
Signed-off-by: Vihas Mak <makvihas@xxxxxxxxx>
Cc: Sean Christopherson <seanjc@xxxxxxxxxx>
Cc: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Cc: Wanpeng Li <wanpengli@xxxxxxxxxxx>
Cc: Jim Mattson <jmattson@xxxxxxxxxx>
Cc: Joerg Roedel <joro@xxxxxxxxxx>
---
arch/x86/kvm/mmu/mmu.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 1d275e9d7..53f4b8b07 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -2586,6 +2586,11 @@ int mmu_try_to_unsync_pages(struct kvm *kvm, const struct kvm_memory_slot *slot,
if (kvm_slot_page_track_is_active(kvm, slot, gfn, KVM_PAGE_TRACK_WRITE))
return -EPERM;
+ if (!can_unsync)
+ return -EPERM;
+
+ if (prefetch)
+ return -EEXIST;
/*
* The page is not write-tracked, mark existing shadow pages unsync
* unless KVM is synchronizing an unsync SP (can_unsync = false). In
@@ -2593,15 +2598,9 @@ int mmu_try_to_unsync_pages(struct kvm *kvm, const struct kvm_memory_slot *slot,
* allowing shadow pages to become unsync (writable by the guest).
*/
for_each_gfn_indirect_valid_sp(kvm, sp, gfn) {
- if (!can_unsync)
- return -EPERM;
-
if (sp->unsync)
continue;
- if (prefetch)
- return -EEXIST;
-
/*
* TDP MMU page faults require an additional spinlock as they
* run with mmu_lock held for read, not write, and the unsync
--
2.30.2
