[PATCH 2/2] KVM: nSVM: Track the ASID generation of the vmcb vmrun through the vmcb

[Cathy Avery]

This patch moves the asid_generation from the vcpu to the vmcb
in order to track the ASID generation that was active the last
time the vmcb was run. If sd->asid_generation changes between
two runs, the old ASID is invalid and must be changed.

Suggested-by: Paolo Bonzini <pbonz...@redhat.com>
Signed-off-by: Cathy Avery <cav...@redhat.com>
---
 arch/x86/kvm/svm/svm.c | 21 +++++++--------------
 arch/x86/kvm/svm/svm.h |  2 +-
 2 files changed, 8 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 5b6998ff7aa1..73e63f7a0acf 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1214,7 +1214,7 @@ static void init_vmcb(struct vcpu_svm *svm)
                save->cr3 = 0;
                save->cr4 = 0;
        }
-       svm->asid_generation = 0;
+       svm->current_vmcb->asid_generation = 0;
        svm->asid = 0;
 
        svm->nested.vmcb12_gpa = 0;
@@ -1296,13 +1296,6 @@ void svm_switch_vmcb(struct vcpu_svm *svm, struct 
kvm_vmcb_info *target_vmcb)
        svm->vmcb = target_vmcb->ptr;
        svm->vmcb_pa = target_vmcb->pa;
 
-       /*
-       * Workaround: we don't yet track the ASID generation
-       * that was active the last time target_vmcb was run.
-       */
-
-       svm->asid_generation = 0;
-
        /*
        * Track the physical CPU the target_vmcb is running on
        * in order to mark the VMCB dirty if the cpu changes at
@@ -1347,7 +1340,6 @@ static int svm_create_vcpu(struct kvm_vcpu *vcpu)
 
        svm_switch_vmcb(svm, &svm->vmcb01);
 
-       svm->asid_generation = 0;
        init_vmcb(svm);
 
        svm_init_osvw(vcpu);
@@ -1784,7 +1776,7 @@ static void new_asid(struct vcpu_svm *svm, struct 
svm_cpu_data *sd)
                vmcb_mark_dirty(svm->vmcb, VMCB_ASID);
        }
 
-       svm->asid_generation = sd->asid_generation;
+       svm->current_vmcb->asid_generation = sd->asid_generation;
        svm->asid = sd->next_asid++;
 }
 
@@ -3179,11 +3171,12 @@ static void pre_svm_run(struct vcpu_svm *svm)
 
        /*
        * If the previous vmrun of the vmcb occurred on
-       * a different physical cpu then we must mark the vmcb dirty.
+       * a different physical cpu then we must mark the vmcb dirty,
+       * update the asid_generation, and assign a new asid.
        */
 
         if (unlikely(svm->current_vmcb->cpu != svm->vcpu.cpu)) {
-               svm->asid_generation = 0;
+               svm->current_vmcb->asid_generation = 0;
                vmcb_mark_all_dirty(svm->vmcb);
                svm->current_vmcb->cpu = svm->vcpu.cpu;
         }
@@ -3192,7 +3185,7 @@ static void pre_svm_run(struct vcpu_svm *svm)
                return pre_sev_run(svm, svm->vcpu.cpu);
 
        /* FIXME: handle wraparound of asid_generation */
-       if (svm->asid_generation != sd->asid_generation)
+       if (svm->current_vmcb->asid_generation != sd->asid_generation)
                new_asid(svm, sd);
 }
 
@@ -3399,7 +3392,7 @@ void svm_flush_tlb(struct kvm_vcpu *vcpu)
        if (static_cpu_has(X86_FEATURE_FLUSHBYASID))
                svm->vmcb->control.tlb_ctl = TLB_CONTROL_FLUSH_ASID;
        else
-               svm->asid_generation--;
+               svm->current_vmcb->asid_generation--;
 }
 
 static void svm_flush_tlb_gva(struct kvm_vcpu *vcpu, gva_t gva)
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 05baee934d03..edcfc2a4e77e 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -86,6 +86,7 @@ struct kvm_vmcb_info {
        struct vmcb *ptr;
        unsigned long pa;
        int cpu;
+       uint64_t asid_generation;
 };
 
 struct svm_nested_state {
@@ -115,7 +116,6 @@ struct vcpu_svm {
        struct kvm_vmcb_info *current_vmcb;
        struct svm_cpu_data *svm_data;
        u32 asid;
-       uint64_t asid_generation;
        uint64_t sysenter_esp;
        uint64_t sysenter_eip;
        uint64_t tsc_aux;
-- 
2.20.1