linux-kernel - [PATCH] KVM: nVMX: Don't return error on nested bitmap memory allocation failure

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Date:	Tue, 28 Apr 2015 15:55:40 -0400
From:	Bandan Das <bsd@...hat.com>
To:	kvm@...r.kernel.org
Cc:	Paolo Bonzini <pbonzini@...hat.com>,
	Jan Kiszka <jan.kiszka@...mens.com>,
	Wincy Van <fanwenyi0529@...il.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH] KVM: nVMX: Don't return error on nested bitmap memory allocation failure


If get_free_page() fails for nested bitmap area, it's evident that
we are gonna get screwed anyway but returning failure because we failed
allocating memory for a nested structure seems like an unnecessary big
hammer. Also, save the call for later; after we are done with other
non-nested allocations.

Signed-off-by: Bandan Das <bsd@...hat.com>
---
 arch/x86/kvm/vmx.c | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index f7b6168..200bc5c 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6039,20 +6039,22 @@ static __init int hardware_setup(void)
 	if (!vmx_msr_bitmap_longmode_x2apic)
 		goto out4;
 
-	if (nested) {
-		vmx_msr_bitmap_nested =
-			(unsigned long *)__get_free_page(GFP_KERNEL);
-		if (!vmx_msr_bitmap_nested)
-			goto out5;
-	}
-
 	vmx_vmread_bitmap = (unsigned long *)__get_free_page(GFP_KERNEL);
 	if (!vmx_vmread_bitmap)
-		goto out6;
+		goto out5;
 
 	vmx_vmwrite_bitmap = (unsigned long *)__get_free_page(GFP_KERNEL);
 	if (!vmx_vmwrite_bitmap)
-		goto out7;
+		goto out6;
+
+	if (nested) {
+		vmx_msr_bitmap_nested =
+			(unsigned long *)__get_free_page(GFP_KERNEL);
+		if (!vmx_msr_bitmap_nested) {
+			printk(KERN_WARNING
+			       "vmx: Failed getting memory for nested bitmap\n");
+			nested = 0;
+	}
 
 	memset(vmx_vmread_bitmap, 0xff, PAGE_SIZE);
 	memset(vmx_vmwrite_bitmap, 0xff, PAGE_SIZE);
@@ -6073,7 +6075,7 @@ static __init int hardware_setup(void)
 
 	if (setup_vmcs_config(&vmcs_config) < 0) {
 		r = -EIO;
-		goto out8;
+		goto out7;
 	}
 
 	if (boot_cpu_has(X86_FEATURE_NX))
@@ -6190,13 +6192,12 @@ static __init int hardware_setup(void)
 
 	return alloc_kvm_area();
 
-out8:
-	free_page((unsigned long)vmx_vmwrite_bitmap);
 out7:
-	free_page((unsigned long)vmx_vmread_bitmap);
-out6:
 	if (nested)
 		free_page((unsigned long)vmx_msr_bitmap_nested);
+	free_page((unsigned long)vmx_vmwrite_bitmap);
+out6:
+	free_page((unsigned long)vmx_vmread_bitmap);
 out5:
 	free_page((unsigned long)vmx_msr_bitmap_longmode_x2apic);
 out4:
-- 
2.1.0

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