[3/5] KVM: Don't follow an atomic operation by a non-atomic one

Commit Message

Avi Kivity March 15, 2010, 11:59 a.m. UTC

None

Patch

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d724a52..2c0f632 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3227,7 +3227,8 @@  static int emulator_write_emulated_onepage(unsigned long addr,
 					   const void *val,
 					   unsigned int bytes,
 					   struct kvm_vcpu *vcpu,
-					   bool guest_initiated)
+					   bool guest_initiated,
+					   bool mmu_only)
 {
 	gpa_t                 gpa;
 	u32 error_code;
@@ -3247,6 +3248,10 @@  static int emulator_write_emulated_onepage(unsigned long addr,
 	if ((gpa & PAGE_MASK) == APIC_DEFAULT_PHYS_BASE)
 		goto mmio;
 
+	if (mmu_only) {
+		kvm_mmu_pte_write(vcpu, gpa, val, bytes, 1);
+		return X86EMUL_CONTINUE;
+	}
 	if (emulator_write_phys(vcpu, gpa, val, bytes))
 		return X86EMUL_CONTINUE;
 
@@ -3271,7 +3276,8 @@  int __emulator_write_emulated(unsigned long addr,
 				   const void *val,
 				   unsigned int bytes,
 				   struct kvm_vcpu *vcpu,
-				   bool guest_initiated)
+				   bool guest_initiated,
+				   bool mmu_only)
 {
 	/* Crossing a page boundary? */
 	if (((addr + bytes - 1) ^ addr) & PAGE_MASK) {
@@ -3279,7 +3285,7 @@  int __emulator_write_emulated(unsigned long addr,
 
 		now = -addr & ~PAGE_MASK;
 		rc = emulator_write_emulated_onepage(addr, val, now, vcpu,
-						     guest_initiated);
+						     guest_initiated, mmu_only);
 		if (rc != X86EMUL_CONTINUE)
 			return rc;
 		addr += now;
@@ -3287,7 +3293,7 @@  int __emulator_write_emulated(unsigned long addr,
 		bytes -= now;
 	}
 	return emulator_write_emulated_onepage(addr, val, bytes, vcpu,
-					       guest_initiated);
+					       guest_initiated, mmu_only);
 }
 
 int emulator_write_emulated(unsigned long addr,
@@ -3295,7 +3301,7 @@  int emulator_write_emulated(unsigned long addr,
 				   unsigned int bytes,
 				   struct kvm_vcpu *vcpu)
 {
-	return __emulator_write_emulated(addr, val, bytes, vcpu, true);
+	return __emulator_write_emulated(addr, val, bytes, vcpu, true, false);
 }
 EXPORT_SYMBOL_GPL(emulator_write_emulated);
 
@@ -3359,6 +3365,8 @@  static int emulator_cmpxchg_emulated(unsigned long addr,
 	if (!exchanged)
 		return X86EMUL_CMPXCHG_FAILED;
 
+	return __emulator_write_emulated(addr, new, bytes, vcpu, true, true);
+
 emul_write:
 	printk_once(KERN_WARNING "kvm: emulating exchange as write\n");
 
@@ -4013,7 +4021,8 @@  int kvm_fix_hypercall(struct kvm_vcpu *vcpu)
 
 	kvm_x86_ops->patch_hypercall(vcpu, instruction);
 
-	return __emulator_write_emulated(rip, instruction, 3, vcpu, false);
+	return __emulator_write_emulated(rip, instruction, 3, vcpu,
+					 false, false);
 }
 
 static u64 mk_cr_64(u64 curr_cr, u32 new_val)