linux-kernel - [PATCH 3.16 30/72] KVM: mmio: cleanup kvm_set_mmio_spte

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Message-ID: <lsq.1575813165.982457359@decadent.org.uk>
Date:   Sun, 08 Dec 2019 13:53:14 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, Denis Kirjanov <kda@...ux-powerpc.org>,
        "Tiejun Chen" <tiejun.chen@...el.com>,
        "Paolo Bonzini" <pbonzini@...hat.com>
Subject: [PATCH 3.16 30/72] KVM: mmio: cleanup kvm_set_mmio_spte_mask

3.16.79-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Tiejun Chen <tiejun.chen@...el.com>

commit d143148383d0395539073dd6c2f25ddf6656bdcc upstream.

Just reuse rsvd_bits() inside kvm_set_mmio_spte_mask()
for slightly better code.

Signed-off-by: Tiejun Chen <tiejun.chen@...el.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
[bwh: Backported to 3.16 as dependency of commit 16cfacc80857
 "KVM: x86: Manually calculate reserved bits when loading PDPTRS"]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 arch/x86/kvm/mmu.c | 5 -----
 arch/x86/kvm/mmu.h | 5 +++++
 arch/x86/kvm/x86.c | 2 +-
 3 files changed, 6 insertions(+), 6 deletions(-)

--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -295,11 +295,6 @@ static bool check_mmio_spte(struct kvm *
 	return likely(kvm_gen == spte_gen);
 }
 
-static inline u64 rsvd_bits(int s, int e)
-{
-	return ((1ULL << (e - s + 1)) - 1) << s;
-}
-
 void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
 		u64 dirty_mask, u64 nx_mask, u64 x_mask)
 {
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -56,6 +56,11 @@
 #define PFERR_RSVD_MASK (1U << PFERR_RSVD_BIT)
 #define PFERR_FETCH_MASK (1U << PFERR_FETCH_BIT)
 
+static inline u64 rsvd_bits(int s, int e)
+{
+	return ((1ULL << (e - s + 1)) - 1) << s;
+}
+
 int kvm_mmu_get_spte_hierarchy(struct kvm_vcpu *vcpu, u64 addr, u64 sptes[4]);
 void kvm_mmu_set_mmio_spte_mask(u64 mmio_mask);
 
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5689,7 +5689,7 @@ static void kvm_set_mmio_spte_mask(void)
 	 * entry to generate page fault with PFER.RSV = 1.
 	 */
 	 /* Mask the reserved physical address bits. */
-	mask = ((1ull << (51 - maxphyaddr + 1)) - 1) << maxphyaddr;
+	mask = rsvd_bits(maxphyaddr, 51);
 
 	/* Bit 62 is always reserved for 32bit host. */
 	mask |= 0x3ull << 62;