From 8d6c45da6da688f310bd8e9960b13efe6c72f7cf Mon Sep 17 00:00:00 2001
From: Marcelo Tosatti <mtosatti@redhat.com>
Date: Thu, 23 Jul 2009 10:42:16 -0300
Subject: [PATCH 2/2] KVM: SVM: force new asid on vcpu migration

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>
(cherry picked from commit 64f3068fd4cd2de030c0859cdb4c265dcfe5382e)
Bugzilla: 513394
Message-ID: <20090723134216.GD25899@amt.cnet>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
RH-Upstream-status: backported-from-upstream
Acked-by: Gleb Natapov <gleb@redhat.com>
Acked-by: Juan Quintela <quintela@redhat.com>
Acked-by: Glauber Costa <glommer@redhat.com>
---
 arch/x86/kvm/svm.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index f6cab53..c7dcbd1 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -710,6 +710,7 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 		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++)
@@ -962,7 +963,6 @@ static void new_asid(struct vcpu_svm *svm, struct svm_cpu_data *svm_data)
 		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++;
 }
@@ -1540,8 +1540,8 @@ static void pre_svm_run(struct vcpu_svm *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);
 }
 
-- 
1.6.3.rc4.29.g8146