Subject: [PATCH 11/24] KVM: arm64: Clean up the checking for huge mapping

From: Marc Zyngier <[email-masked]>
Date: Fri, 29 May 2020 17:01:08 +0100

From: Suzuki K Poulose <[email-masked]>

If we are checking whether the stage2 can map PAGE_SIZE,
we don't have to do the boundary checks as both the host
VMA and the guest memslots are page aligned. Bail the case
easily.

While we're at it, fixup a typo in the comment below.

Signed-off-by: Suzuki K Poulose <[email-masked]>
Signed-off-by: Zenghui Yu <[email-masked]>
Signed-off-by: Marc Zyngier <[email-masked]>
Link: https://lore.kernel.org/r/[email-masked]
---
 arch/arm64/kvm/mmu.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 917363375e8a..ccb44e7d30d9 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1610,6 +1610,10 @@ static bool fault_supports_stage2_huge_mapping(struct kvm_memory_slot *memslot,
 	hva_t uaddr_start, uaddr_end;
 	size_t size;
 
+	/* The memslot and the VMA are guaranteed to be aligned to PAGE_SIZE */
+	if (map_size == PAGE_SIZE)
+		return true;
+
 	size = memslot->npages * PAGE_SIZE;
 
 	gpa_start = memslot->base_gfn << PAGE_SHIFT;
@@ -1629,7 +1633,7 @@ static bool fault_supports_stage2_huge_mapping(struct kvm_memory_slot *memslot,
 	 *    |abcde|fgh  Stage-1 block  |    Stage-1 block tv|xyz|
 	 *    +-----+--------------------+--------------------+---+
 	 *
-	 *    memslot->base_gfn << PAGE_SIZE:
+	 *    memslot->base_gfn << PAGE_SHIFT:
 	 *      +---+--------------------+--------------------+-----+
 	 *      |abc|def  Stage-2 block  |    Stage-2 block   |tvxyz|
 	 *      +---+--------------------+--------------------+-----+
-- 
2.26.2

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