releases/2.6.30.6/kvm-svm-force-new-asid-on-vcpu-migration.patch

From mtosatti@redhat.com  Thu Sep  3 14:26:07 2009
From: Marcelo Tosatti <mtosatti@redhat.com>
Date: Tue,  1 Sep 2009 12:15:11 -0300
Subject: KVM: SVM: force new asid on vcpu migration
To: stable@kernel.org
Cc: Marcelo Tosatti <mtosatti@redhat.com>, avi@redhat.com
Message-ID: <1251818115-22157-3-git-send-email-mtosatti@redhat.com>

From: Marcelo Tosatti <mtosatti@redhat.com>

(cherry picked from commit 4b656b1202498184a0ecef86b3b89ff613b9c6ab)

If a migrated vcpu matches the asid_generation value of the target pcpu,
there will be no TLB flush via TLB_CONTROL_FLUSH_ALL_ASID.

The check for vcpu.cpu in pre_svm_run is meaningless since svm_vcpu_load
already updated it on schedule in.

Such vcpu will VMRUN with stale TLB entries.

Based on original patch from Joerg Roedel (http://patchwork.kernel.org/patch/10021/)

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Acked-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 arch/x86/kvm/svm.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -736,6 +736,7 @@ static void svm_vcpu_load(struct kvm_vcp
 		svm->vmcb->control.tsc_offset += delta;
 		vcpu->cpu = cpu;
 		kvm_migrate_timers(vcpu);
+		svm->asid_generation = 0;
 	}
 
 	for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++)
@@ -1046,7 +1047,6 @@ static void new_asid(struct vcpu_svm *sv
 		svm->vmcb->control.tlb_ctl = TLB_CONTROL_FLUSH_ALL_ASID;
 	}
 
-	svm->vcpu.cpu = svm_data->cpu;
 	svm->asid_generation = svm_data->asid_generation;
 	svm->vmcb->control.asid = svm_data->next_asid++;
 }
@@ -2258,8 +2258,8 @@ static void pre_svm_run(struct vcpu_svm 
 	struct svm_cpu_data *svm_data = per_cpu(svm_data, cpu);
 
 	svm->vmcb->control.tlb_ctl = TLB_CONTROL_DO_NOTHING;
-	if (svm->vcpu.cpu != cpu ||
-	    svm->asid_generation != svm_data->asid_generation)
+	/* FIXME: handle wraparound of asid_generation */
+	if (svm->asid_generation != svm_data->asid_generation)
 		new_asid(svm, svm_data);
 }