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From:   KarimAllah Ahmed <karahmed@amazon.de>
To:     x86@kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc:     hpa@zytor.com, jmattson@google.com, mingo@redhat.com,
        pbonzini@redhat.com, rkrcmar@redhat.com, tglx@linutronix.de,
        KarimAllah Ahmed <karahmed@amazon.de>
Subject: [PATCH 08/10] KVM/X86: Use kvm_vcpu_map in emulator_cmpxchg_emulated
Date:   Wed, 21 Feb 2018 18:47:19 +0100
Message-Id: <1519235241-6500-9-git-send-email-karahmed@amazon.de>
In-Reply-To: <1519235241-6500-1-git-send-email-karahmed@amazon.de>
References: <1519235241-6500-1-git-send-email-karahmed@amazon.de>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

... since using kvm_vcpu_gpa_to_page() and kmap() will only work for guest
memory that has a "struct page".

Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
---
 arch/x86/kvm/x86.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 37f5df9..197a395 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5013,9 +5013,9 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt,
 				     unsigned int bytes,
 				     struct x86_exception *exception)
 {
+	struct kvm_host_map map;
 	struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
 	gpa_t gpa;
-	struct page *page;
 	char *kaddr;
 	bool exchanged;
 
@@ -5032,12 +5032,11 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt,
 	if (((gpa + bytes - 1) & PAGE_MASK) != (gpa & PAGE_MASK))
 		goto emul_write;
 
-	page = kvm_vcpu_gfn_to_page(vcpu, gpa >> PAGE_SHIFT);
-	if (is_error_page(page))
+	if (!kvm_vcpu_map(vcpu, gpa_to_gfn(gpa), &map))
 		goto emul_write;
 
-	kaddr = kmap_atomic(page);
-	kaddr += offset_in_page(gpa);
+	kaddr = map.kaddr + offset_in_page(gpa);
+
 	switch (bytes) {
 	case 1:
 		exchanged = CMPXCHG_TYPE(u8, kaddr, old, new);
@@ -5054,8 +5053,8 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt,
 	default:
 		BUG();
 	}
-	kunmap_atomic(kaddr);
-	kvm_release_page_dirty(page);
+
+	kvm_vcpu_unmap(&map);
 
 	if (!exchanged)
 		return X86EMUL_CMPXCHG_FAILED;
-- 
2.7.4