linux-kernel - [PATCH 1/3] KVM: x86: simplify ept

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Date:   Thu, 17 Aug 2017 18:36:56 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     wanpeng.li@...mail.com, rkrcmar@...hat.com, david@...hat.com
Subject: [PATCH 1/3] KVM: x86: simplify ept_misconfig

Calling handle_mmio_page_fault() has been unnecessary since commit
e9ee956e311d ("KVM: x86: MMU: Move handle_mmio_page_fault() call to
kvm_mmu_page_fault()", 2016-02-22).

handle_mmio_page_fault() can now be made static.

Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
	v1->v2: make the function static.

 arch/x86/kvm/mmu.c | 19 ++++++++++++++++++-
 arch/x86/kvm/mmu.h | 17 -----------------
 arch/x86/kvm/vmx.c | 13 +++----------
 3 files changed, 21 insertions(+), 28 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index e721e10afda1..f7598883920a 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3648,7 +3648,23 @@ static bool mmio_info_in_cache(struct kvm_vcpu *vcpu, u64 addr, bool direct)
 	return reserved;
 }
 
-int handle_mmio_page_fault(struct kvm_vcpu *vcpu, u64 addr, bool direct)
+/*
+ * Return values of handle_mmio_page_fault:
+ * RET_MMIO_PF_EMULATE: it is a real mmio page fault, emulate the instruction
+ *			directly.
+ * RET_MMIO_PF_INVALID: invalid spte is detected then let the real page
+ *			fault path update the mmio spte.
+ * RET_MMIO_PF_RETRY: let CPU fault again on the address.
+ * RET_MMIO_PF_BUG: a bug was detected (and a WARN was printed).
+ */
+enum {
+	RET_MMIO_PF_EMULATE = 1,
+	RET_MMIO_PF_INVALID = 2,
+	RET_MMIO_PF_RETRY = 0,
+	RET_MMIO_PF_BUG = -1
+};
+
+static int handle_mmio_page_fault(struct kvm_vcpu *vcpu, u64 addr, bool direct)
 {
 	u64 spte;
 	bool reserved;
@@ -4837,6 +4853,7 @@ int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u64 error_code,
 			return 1;
 		if (r < 0)
 			return r;
+		/* Must be RET_MMIO_PF_INVALID.  */
 	}
 
 	r = vcpu->arch.mmu.page_fault(vcpu, cr2, lower_32_bits(error_code),
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index d7d248a000dd..3ed6192d93b1 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -56,23 +56,6 @@ static inline u64 rsvd_bits(int s, int e)
 void
 reset_shadow_zero_bits_mask(struct kvm_vcpu *vcpu, struct kvm_mmu *context);
 
-/*
- * Return values of handle_mmio_page_fault:
- * RET_MMIO_PF_EMULATE: it is a real mmio page fault, emulate the instruction
- *			directly.
- * RET_MMIO_PF_INVALID: invalid spte is detected then let the real page
- *			fault path update the mmio spte.
- * RET_MMIO_PF_RETRY: let CPU fault again on the address.
- * RET_MMIO_PF_BUG: a bug was detected (and a WARN was printed).
- */
-enum {
-	RET_MMIO_PF_EMULATE = 1,
-	RET_MMIO_PF_INVALID = 2,
-	RET_MMIO_PF_RETRY = 0,
-	RET_MMIO_PF_BUG = -1
-};
-
-int handle_mmio_page_fault(struct kvm_vcpu *vcpu, u64 addr, bool direct);
 void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu);
 void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
 			     bool accessed_dirty);
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index df8d2f127508..45fb0ea78ee8 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6410,17 +6410,10 @@ static int handle_ept_misconfig(struct kvm_vcpu *vcpu)
 		return kvm_skip_emulated_instruction(vcpu);
 	}
 
-	ret = handle_mmio_page_fault(vcpu, gpa, true);
 	vcpu->arch.gpa_available = true;
-	if (likely(ret == RET_MMIO_PF_EMULATE))
-		return x86_emulate_instruction(vcpu, gpa, 0, NULL, 0) ==
-					      EMULATE_DONE;
-
-	if (unlikely(ret == RET_MMIO_PF_INVALID))
-		return kvm_mmu_page_fault(vcpu, gpa, 0, NULL, 0);
-
-	if (unlikely(ret == RET_MMIO_PF_RETRY))
-		return 1;
+	ret = kvm_mmu_page_fault(vcpu, gpa, PFERR_RSVD_MASK, NULL, 0);
+	if (ret >= 0)
+		return ret;
 
 	/* It is the real ept misconfig */
 	WARN_ON(1);
-- 
1.8.3.1