Linux Virtualization - Jan 2008 - [PATCH] KVM: add KVM_SYNC_SHADOW_WITH_USER ioctl

The host needs to zap its shadow entries before performing an inflate
operation to avoid the guest from using stale ones.

So add an ioctl to interface with kvm_mmu_zap_all().

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Index: kvm.quilt/arch/x86/kvm/x86.c
==================================================================---
kvm.quilt.orig/arch/x86/kvm/x86.c
+++ kvm.quilt/arch/x86/kvm/x86.c
@@ -680,6 +680,7 @@ int kvm_dev_ioctl_check_extension(long e
 	case KVM_CAP_USER_MEMORY:
 	case KVM_CAP_SET_TSS_ADDR:
 	case KVM_CAP_EXT_CPUID:
+	case KVM_CAP_SYNC_SHADOW_WITH_USER:
 		r = 1;
 		break;
 	case KVM_CAP_VAPIC:
Index: kvm.quilt/include/linux/kvm.h
==================================================================---
kvm.quilt.orig/include/linux/kvm.h
+++ kvm.quilt/include/linux/kvm.h
@@ -249,6 +249,7 @@ struct kvm_vapic_addr {
 #define KVM_CAP_SET_TSS_ADDR 4
 #define KVM_CAP_EXT_CPUID 5
 #define KVM_CAP_VAPIC 6
+#define KVM_CAP_SYNC_SHADOW_WITH_USER 7
 
 /*
  * ioctls for VM fds
@@ -267,6 +268,7 @@ struct kvm_vapic_addr {
 #define KVM_GET_DIRTY_LOG         _IOW(KVMIO, 0x42, struct kvm_dirty_log)
 #define KVM_SET_MEMORY_ALIAS      _IOW(KVMIO, 0x43, struct kvm_memory_alias)
 #define KVM_GET_SUPPORTED_CPUID   _IOWR(KVMIO, 0x48, struct kvm_cpuid2)
+#define KVM_SYNC_SHADOW_WITH_USER _IO(KVMIO, 0x49)
 /* Device model IOC */
 #define KVM_CREATE_IRQCHIP	  _IO(KVMIO,  0x60)
 #define KVM_IRQ_LINE		  _IOW(KVMIO, 0x61, struct kvm_irq_level)
Index: kvm.quilt/virt/kvm/kvm_main.c
==================================================================---
kvm.quilt.orig/virt/kvm/kvm_main.c
+++ kvm.quilt/virt/kvm/kvm_main.c
@@ -971,6 +971,11 @@ static long kvm_vm_ioctl(struct file *fi
 			goto out;
 		break;
 	}
+	case KVM_SYNC_SHADOW_WITH_USER: {
+		r = 0;
+		kvm_mmu_zap_all(kvm);
+		break;
+	}
 	default:
 		r = kvm_arch_vm_ioctl(filp, ioctl, arg);
 	}

Marcelo Tosatti wrote:
> The host needs to zap its shadow entries before performing an inflate
> operation to avoid the guest from using stale ones.
>
> So add an ioctl to interface with kvm_mmu_zap_all().
>
> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
>
> Index: kvm.quilt/virt/kvm/kvm_main.c
> ==================================================================> ---
kvm.quilt.orig/virt/kvm/kvm_main.c
> +++ kvm.quilt/virt/kvm/kvm_main.c
> @@ -971,6 +971,11 @@ static long kvm_vm_ioctl(struct file *fi
>  			goto out;
>  		break;
>  	}
> +	case KVM_SYNC_SHADOW_WITH_USER: {
> +		r = 0;
> +		kvm_mmu_zap_all(kvm);
> +		break;
> +	}
>   
It should go into the arch ioctl below since the mmu is under
x86
>  	default:
>  		r = kvm_arch_vm_ioctl(filp, ioctl, arg);
>  	}
>
>
>