[PATCH 1/2] kvm: Insist on a reason when injecting a #GP into a guest

[Rusty Russell <rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>]

Insist on a reason when injecting a #GP into a guest

All places but one already do a printk before injecting a #GP: just
formalize it a little.

Signed-off-by: Rusty Russell <rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>

diff -r f75b0a5fc387 drivers/kvm/kvm_main.c
--- a/drivers/kvm/kvm_main.c	Mon Jul 23 11:16:12 2007 +1000
+++ b/drivers/kvm/kvm_main.c	Mon Jul 23 16:59:56 2007 +1000
@@ -419,8 +419,15 @@ static int kvm_vm_release(struct inode *
 	return 0;
 }
 
-static void inject_gp(struct kvm_vcpu *vcpu)
-{
+static void __attribute__((format(printf, 2, 3)))
+inject_gp(struct kvm_vcpu *vcpu, const char *why_fmt, ...)
+{
+	va_list args;
+
+	va_start(args, why_fmt);
+	printk(KERN_DEBUG "kvm: #GP ");
+	vprintk(why_fmt, args);
+	va_end(args);
 	kvm_arch_ops->inject_gp(vcpu, 0);
 }
 
@@ -464,22 +471,21 @@ void set_cr0(struct kvm_vcpu *vcpu, unsi
 void set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
 {
 	if (cr0 & CR0_RESERVED_BITS) {
-		printk(KERN_DEBUG "set_cr0: 0x%lx #GP, reserved bits 0x%lx\n",
-		       cr0, vcpu->cr0);
-		inject_gp(vcpu);
+		inject_gp(vcpu,
+			  "set_cr0: 0x%lx reserved bits 0x%lx\n",
+			  cr0, vcpu->cr0);
 		return;
 	}
 
 	if ((cr0 & X86_CR0_NW) && !(cr0 & X86_CR0_CD)) {
-		printk(KERN_DEBUG "set_cr0: #GP, CD == 0 && NW == 1\n");
-		inject_gp(vcpu);
+		inject_gp(vcpu,
+			  "set_cr0: CD == 0 && NW == 1\n");
 		return;
 	}
 
 	if ((cr0 & X86_CR0_PG) && !(cr0 & X86_CR0_PE)) {
-		printk(KERN_DEBUG "set_cr0: #GP, set PG flag "
-		       "and a clear PE flag\n");
-		inject_gp(vcpu);
+		inject_gp(vcpu,
+			  "set_cr0: set PG flag and a clear PE flag\n");
 		return;
 	}
 
@@ -489,25 +495,23 @@ void set_cr0(struct kvm_vcpu *vcpu, unsi
 			int cs_db, cs_l;
 
 			if (!is_pae(vcpu)) {
-				printk(KERN_DEBUG "set_cr0: #GP, start paging "
-				       "in long mode while PAE is disabled\n");
-				inject_gp(vcpu);
+				inject_gp(vcpu,
+					  "set_cr0: start paging in long"
+					  " mode while PAE is disabled\n");
 				return;
 			}
 			kvm_arch_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l);
 			if (cs_l) {
-				printk(KERN_DEBUG "set_cr0: #GP, start paging "
-				       "in long mode while CS.L == 1\n");
-				inject_gp(vcpu);
+				inject_gp(vcpu,
+					  "set_cr0: start paging "
+					  "in long mode while CS.L == 1\n");
 				return;
 
 			}
 		} else
 #endif
 		if (is_pae(vcpu) && !load_pdptrs(vcpu, vcpu->cr3)) {
-			printk(KERN_DEBUG "set_cr0: #GP, pdptrs "
-			       "reserved bits\n");
-			inject_gp(vcpu);
+			inject_gp(vcpu, "set_cr0: pdptrs reserved bits\n");
 			return;
 		}
 
@@ -532,28 +536,24 @@ void set_cr4(struct kvm_vcpu *vcpu, unsi
 void set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
 {
 	if (cr4 & CR4_RESERVED_BITS) {
-		printk(KERN_DEBUG "set_cr4: #GP, reserved bits\n");
-		inject_gp(vcpu);
+		inject_gp(vcpu, "set_cr4: reserved bits\n");
 		return;
 	}
 
 	if (is_long_mode(vcpu)) {
 		if (!(cr4 & X86_CR4_PAE)) {
-			printk(KERN_DEBUG "set_cr4: #GP, clearing PAE while "
-			       "in long mode\n");
-			inject_gp(vcpu);
+			inject_gp(vcpu, "set_cr4: clearing PAE while "
+				  "in long mode\n");
 			return;
 		}
 	} else if (is_paging(vcpu) && !is_pae(vcpu) && (cr4 & X86_CR4_PAE)
 		   && !load_pdptrs(vcpu, vcpu->cr3)) {
-		printk(KERN_DEBUG "set_cr4: #GP, pdptrs reserved bits\n");
-		inject_gp(vcpu);
+		inject_gp(vcpu, "set_cr4: pdptrs reserved bits\n");
 		return;
 	}
 
 	if (cr4 & X86_CR4_VMXE) {
-		printk(KERN_DEBUG "set_cr4: #GP, setting VMXE\n");
-		inject_gp(vcpu);
+		inject_gp(vcpu, "set_cr4: setting VMXE\n");
 		return;
 	}
 	kvm_arch_ops->set_cr4(vcpu, cr4);
@@ -566,29 +566,24 @@ void set_cr3(struct kvm_vcpu *vcpu, unsi
 {
 	if (is_long_mode(vcpu)) {
 		if (cr3 & CR3_L_MODE_RESERVED_BITS) {
-			printk(KERN_DEBUG "set_cr3: #GP, reserved bits\n");
-			inject_gp(vcpu);
+			inject_gp(vcpu, "set_cr3: reserved bits\n");
 			return;
 		}
 	} else {
 		if (is_pae(vcpu)) {
 			if (cr3 & CR3_PAE_RESERVED_BITS) {
-				printk(KERN_DEBUG
-				       "set_cr3: #GP, reserved bits\n");
-				inject_gp(vcpu);
+				inject_gp(vcpu, "set_cr3: reserved bits\n");
 				return;
 			}
 			if (is_paging(vcpu) && !load_pdptrs(vcpu, cr3)) {
-				printk(KERN_DEBUG "set_cr3: #GP, pdptrs "
+				inject_gp(vcpu, "set_cr3: pdptrs "
 				       "reserved bits\n");
-				inject_gp(vcpu);
 				return;
 			}
 		} else {
 			if (cr3 & CR3_NONPAE_RESERVED_BITS) {
-				printk(KERN_DEBUG
-				       "set_cr3: #GP, reserved bits\n");
-				inject_gp(vcpu);
+				inject_gp(vcpu, "set_cr3: reserved bits\n");
+
 				return;
 			}
 		}
@@ -606,7 +601,7 @@ void set_cr3(struct kvm_vcpu *vcpu, unsi
 	 * to debug) behavior on the guest side.
 	 */
 	if (unlikely(!gfn_to_memslot(vcpu->kvm, cr3 >> PAGE_SHIFT)))
-		inject_gp(vcpu);
+		inject_gp(vcpu, "set_cr3: 0x%lx not valid guest phys", cr3);
 	else
 		vcpu->mmu.new_cr3(vcpu);
 	spin_unlock(&vcpu->kvm->lock);
@@ -616,8 +611,7 @@ void set_cr8(struct kvm_vcpu *vcpu, unsi
 void set_cr8(struct kvm_vcpu *vcpu, unsigned long cr8)
 {
 	if (cr8 & CR8_RESERVED_BITS) {
-		printk(KERN_DEBUG "set_cr8: #GP, reserved bits 0x%lx\n", cr8);
-		inject_gp(vcpu);
+		inject_gp(vcpu, "set_cr8: reserved bits 0x%lx\n", cr8);
 		return;
 	}
 	vcpu->cr8 = cr8;
@@ -1533,16 +1527,13 @@ static void set_efer(struct kvm_vcpu *vc
 static void set_efer(struct kvm_vcpu *vcpu, u64 efer)
 {
 	if (efer & EFER_RESERVED_BITS) {
-		printk(KERN_DEBUG "set_efer: 0x%llx #GP, reserved bits\n",
-		       efer);
-		inject_gp(vcpu);
+		inject_gp(vcpu, "set_efer: 0x%llx reserved bits\n", efer);
 		return;
 	}
 
 	if (is_paging(vcpu)
 	    && (vcpu->shadow_efer & EFER_LME) != (efer & EFER_LME)) {
-		printk(KERN_DEBUG "set_efer: #GP, change LME while paging\n");
-		inject_gp(vcpu);
+		inject_gp(vcpu, "set_efer: change LME while paging\n");
 		return;
 	}
 
@@ -1843,8 +1834,7 @@ int kvm_setup_pio(struct kvm_vcpu *vcpu,
 		/*
 		 * String I/O in reverse.  Yuck.  Kill the guest, fix later.
 		 */
-		printk(KERN_ERR "kvm: guest string pio down\n");
-		inject_gp(vcpu);
+		inject_gp(vcpu, "guest string pio down\n");
 		return 1;
 	}
 	vcpu->run->io.count = now;
@@ -1858,7 +1848,8 @@ int kvm_setup_pio(struct kvm_vcpu *vcpu,
 		vcpu->pio.guest_pages[i] = page;
 		spin_unlock(&vcpu->kvm->lock);
 		if (!page) {
-			inject_gp(vcpu);
+			inject_gp(vcpu, "pio: invalid address %#lx\n",
+				  address + i * PAGE_SIZE);
 			free_pio_guest_pages(vcpu);
 			return 1;
 		}



-------------------------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc.
Still grepping through log files to find problems?  Stop.
Now Search log events and configuration files using AJAX and a browser.
Download your FREE copy of Splunk now >>  http://get.splunk.com/