Re: cr3 OOS optimisation breaks 32-bit GNU/kFreeBSD guest

[Marcelo Tosatti <mtosatti@redhat.com>]

On Sun, Mar 22, 2009 at 11:35:00AM +0200, Avi Kivity wrote:
> Good catch, indeed.  But is it sufficient?  We could unlink a page  
> through other means, for example by the guest zapping a page directory  
> entry.  

Yep.

> Maybe it's best to resync when relinking a global page?

How about this. It will shorten the unsync period of global pages,
unfortunately.

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 2a36f7f..bccdcc7 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1238,6 +1238,10 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
 				set_bit(KVM_REQ_MMU_SYNC, &vcpu->requests);
 				kvm_mmu_mark_parents_unsync(vcpu, sp);
 			}
+			if (role.level != PT_PAGE_TABLE_LEVEL &&
+			    !list_empty(&vcpu->kvm->arch.oos_global_pages))
+				set_bit(KVM_REQ_MMU_GLOBAL_SYNC, &vcpu->requests);
+
 			pgprintk("%s: found\n", __func__);
 			return sp;
 		}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2ea8262..48169d7 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3109,6 +3109,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 			kvm_write_guest_time(vcpu);
 		if (test_and_clear_bit(KVM_REQ_MMU_SYNC, &vcpu->requests))
 			kvm_mmu_sync_roots(vcpu);
+		if (test_and_clear_bit(KVM_REQ_MMU_GLOBAL_SYNC, &vcpu->requests))
+			kvm_mmu_sync_global(vcpu);
 		if (test_and_clear_bit(KVM_REQ_TLB_FLUSH, &vcpu->requests))
 			kvm_x86_ops->tlb_flush(vcpu);
 		if (test_and_clear_bit(KVM_REQ_REPORT_TPR_ACCESS,
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 11eb702..8efd6e3 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -37,7 +37,8 @@
 #define KVM_REQ_PENDING_TIMER      5
 #define KVM_REQ_UNHALT             6
 #define KVM_REQ_MMU_SYNC           7
-#define KVM_REQ_KVMCLOCK_UPDATE    8
+#define KVM_REQ_MMU_GLOBAL_SYNC    8	  
+#define KVM_REQ_KVMCLOCK_UPDATE    9
 
 #define KVM_USERSPACE_IRQ_SOURCE_ID	0