[PATCH 0/3] KVM: Miscellaneous stabilization fixes

Avi Kivity

author

2006-12-31 13:18 UTC #0 lore raw

cover KVM: Miscellaneous stabilization fixes

A trio of fixes for miscellaneous problems, that don't affect usage under normal .configs and usage. However they do need fixing.

Signature · 8 lines

error compiling committee.c: too many arguments to function


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Avi Kivity

author

2006-12-31 13:19 UTC #1 lore raw

PATCH 1/3 KVM: Fix GFP_KERNEL alloc in atomic section bug

From: Ingo Molnar <[email protected]>

KVM does kmalloc() in an atomic section while having preemption disabled via vcpu_load(). Fix this by moving the ->*_msr setup from the vcpu_setup method to the vcpu_create method.

(This is also a small speedup for setting up a vcpu, which can in theory be more frequent than the vcpu_create method).

Signed-off-by Ingo Molnar <[email protected]>

Signed-off-by Avi Kivity <avi-atKUWr5tajBWk0Htik3J/[email protected]>

drivers/kvm/vmx.c +21 ~~-11~~

Index: linux-2.6/drivers/kvm/vmx.c
===================================================================
@@ -1094,14 +1094,6 @@ static int vmx_vcpu_setup(struct kvm_vcp
 	rdmsrl(MSR_IA32_SYSENTER_EIP, a);
 	vmcs_writel(HOST_IA32_SYSENTER_EIP, a);   /* 22.2.3 */
 
-	ret = -ENOMEM;
-	vcpu->guest_msrs = kmalloc(PAGE_SIZE, GFP_KERNEL);
-	if (!vcpu->guest_msrs)
-		goto out;
-	vcpu->host_msrs = kmalloc(PAGE_SIZE, GFP_KERNEL);
-	if (!vcpu->host_msrs)
-		goto out_free_guest_msrs;
-
 	for (i = 0; i < NR_VMX_MSR; ++i) {
 		u32 index = vmx_msr_index[i];
 		u32 data_low, data_high;

@@ -1155,8 +1147,6 @@ static int vmx_vcpu_setup(struct kvm_vcp
 
 	return 0;
 
-out_free_guest_msrs:
-	kfree(vcpu->guest_msrs);
 out:
 	return ret;
 }

@@ -1906,13 +1896,33 @@ static int vmx_create_vcpu(struct kvm_vc
 {
 	struct vmcs *vmcs;
 
+	vcpu->guest_msrs = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!vcpu->guest_msrs)
+		return -ENOMEM;
+
+	vcpu->host_msrs = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!vcpu->host_msrs)
+		goto out_free_guest_msrs;
+
 	vmcs = alloc_vmcs();
 	if (!vmcs)
-		return -ENOMEM;
+		goto out_free_msrs;
+
 	vmcs_clear(vmcs);
 	vcpu->vmcs = vmcs;
 	vcpu->launched = 0;
+
 	return 0;
+
+out_free_msrs:
+	kfree(vcpu->host_msrs);
+	vcpu->host_msrs = NULL;
+
+out_free_guest_msrs:
+	kfree(vcpu->guest_msrs);
+	vcpu->guest_msrs = NULL;
+
+	return -ENOMEM;
 }
 
 static struct kvm_arch_ops vmx_arch_ops = {

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Avi Kivity

author

2006-12-31 13:20 UTC #2 lore raw

PATCH 2/3 KVM: Use raw_smp_processor_id() instead of smp_processor_id() where applicable

In reply to Avi Kivity

From: Ingo Molnar <[email protected]>

Signed-off-by Avi Kivity <avi-atKUWr5tajBWk0Htik3J/[email protected]>

drivers/kvm/vmx.c +2 -2

Index: linux-2.6/drivers/kvm/vmx.c
===================================================================
@@ -116,7 +116,7 @@ static void vmcs_clear(struct vmcs *vmcs
 static void __vcpu_clear(void *arg)
 {
 	struct kvm_vcpu *vcpu = arg;
-	int cpu = smp_processor_id();
+	int cpu = raw_smp_processor_id();
 
 	if (vcpu->cpu == cpu)
 		vmcs_clear(vcpu->vmcs);

@@ -541,7 +541,7 @@ static struct vmcs *alloc_vmcs_cpu(int c
 
 static struct vmcs *alloc_vmcs(void)
 {
-	return alloc_vmcs_cpu(smp_processor_id());
+	return alloc_vmcs_cpu(raw_smp_processor_id());
 }
 
 static void free_vmcs(struct vmcs *vmcs)

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Avi Kivity

author

2006-12-31 13:21 UTC #3 lore raw

PATCH 3/3 KVM: Recover after an arch module load failure

In reply to Avi Kivity

From: Yoshimi Ichiyanagi <[email protected]>

If we load the wrong arch module, it leaves behind kvm_arch_ops set, which prevents loading of the correct arch module later.

Fix be not setting kvm_arch_ops until we're sure it's good.

Signed-off-by Yoshimi Ichiyanagi <[email protected]>

Signed-off-by Avi Kivity <avi-atKUWr5tajBWk0Htik3J/[email protected]>

drivers/kvm/kvm_main.c +4 -4

Index: linux-2.6/drivers/kvm/kvm_main.c
===================================================================
@@ -1944,17 +1944,17 @@ int kvm_init_arch(struct kvm_arch_ops *o
 		return -EEXIST;
 	}
 
-	kvm_arch_ops = ops;
-
-	if (!kvm_arch_ops->cpu_has_kvm_support()) {
+	if (!ops->cpu_has_kvm_support()) {
 		printk(KERN_ERR "kvm: no hardware support\n");
 		return -EOPNOTSUPP;
 	}
-	if (kvm_arch_ops->disabled_by_bios()) {
+	if (ops->disabled_by_bios()) {
 		printk(KERN_ERR "kvm: disabled by bios\n");
 		return -EOPNOTSUPP;
 	}
 
+	kvm_arch_ops = ops;
+
 	r = kvm_arch_ops->hardware_setup();
 	if (r < 0)
 	    return r;

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