linux-kernel - [PATCH 1/5] KVM: x86/mmu: Return a u64 (the old SPTE) from mmu_spte_clear_track

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Date:   Tue, 12 Jul 2022 01:55:54 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/5] KVM: x86/mmu: Return a u64 (the old SPTE) from mmu_spte_clear_track_bits()

Return a u64, not an int, from mmu_spte_clear_track_bits().  The return
value is the old SPTE value, which is very much a 64-bit value.  The sole
caller that consumes the return value, drop_spte(), already uses a u64.
The only reason that truncating the SPTE value is not problematic is
because drop_spte() only queries the shadow-present bit, which is in the
lower 32 bits.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/mmu/mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index f7fa4c31b7c5..2605d6ebc193 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -529,7 +529,7 @@ static bool mmu_spte_update(u64 *sptep, u64 new_spte)
  * state bits, it is used to clear the last level sptep.
  * Returns the old PTE.
  */
-static int mmu_spte_clear_track_bits(struct kvm *kvm, u64 *sptep)
+static u64 mmu_spte_clear_track_bits(struct kvm *kvm, u64 *sptep)
 {
 	kvm_pfn_t pfn;
 	u64 old_spte = *sptep;
-- 
2.37.0.144.g8ac04bfd2-goog