From: Avi Kivity <avi@qumranet.com>
Date: Sat, 6 Jan 2007 00:36:56 +0000 (-0800)
Subject: [PATCH] KVM: Improve reporting of vmwrite errors
X-Git-Tag: v2.6.20-rc4~23
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e52de1b8cf85aa2ccaaa253b4397c6d6cc0d4897;p=linux-2.6

[PATCH] KVM: Improve reporting of vmwrite errors

This will allow us to see the root cause when a vmwrite error happens.

Signed-off-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index ed39567397..779d8fc07d 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -152,15 +152,21 @@ static u64 vmcs_read64(unsigned long field)
 #endif
 }
 
+static noinline void vmwrite_error(unsigned long field, unsigned long value)
+{
+	printk(KERN_ERR "vmwrite error: reg %lx value %lx (err %d)\n",
+	       field, value, vmcs_read32(VM_INSTRUCTION_ERROR));
+	dump_stack();
+}
+
 static void vmcs_writel(unsigned long field, unsigned long value)
 {
 	u8 error;
 
 	asm volatile (ASM_VMX_VMWRITE_RAX_RDX "; setna %0"
 		       : "=q"(error) : "a"(value), "d"(field) : "cc" );
-	if (error)
-		printk(KERN_ERR "vmwrite error: reg %lx value %lx (err %d)\n",
-		       field, value, vmcs_read32(VM_INSTRUCTION_ERROR));
+	if (unlikely(error))
+		vmwrite_error(field, value);
 }
 
 static void vmcs_write16(unsigned long field, u16 value)