linux-kernel - [PATCH 2/3] KVM: arm64: Don't map PUD huge page if it's not available

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Date:   Sun, 25 Oct 2020 11:27:38 +1100
From:   Gavin Shan <gshan@...hat.com>
To:     kvmarm@...ts.cs.columbia.edu
Cc:     linux-kernel@...r.kernel.org, will@...nel.org,
        alexandru.elisei@....com, maz@...nel.org
Subject: [PATCH 2/3] KVM: arm64: Don't map PUD huge page if it's not available

PUD huge page isn't available when CONFIG_ARM64_4K_PAGES is disabled.
In this case, we needn't try to map the memory through PUD huge pages
to save some CPU cycles in the hot path.

This also corrects the code style issue, which was introduced by
commit <523b3999e5f6> ("KVM: arm64: Try PMD block mappings if PUD mappings
are not supported").

Signed-off-by: Gavin Shan <gshan@...hat.com>
---
 arch/arm64/kvm/mmu.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index a816cb8e619b..0f51585adc04 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -787,9 +787,11 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 		vma_shift = PAGE_SHIFT;
 	}
 
+#ifdef CONFIG_ARM64_4K_PAGES
 	if (vma_shift == PUD_SHIFT &&
 	    !fault_supports_stage2_huge_mapping(memslot, hva, PUD_SIZE))
-	       vma_shift = PMD_SHIFT;
+		vma_shift = PMD_SHIFT;
+#endif
 
 	if (vma_shift == PMD_SHIFT &&
 	    !fault_supports_stage2_huge_mapping(memslot, hva, PMD_SIZE)) {
-- 
2.23.0