[Xen-changelog] [xen master] x86/vlapic: fixes for HVM code when running without a vlapic

[patchbot@xxxxxxx]

commit 302a8519fb8537f619569873d605f65eb18f4bdc
Author:     Roger Pau Monné <roger.pau@xxxxxxxxxx>
AuthorDate: Thu Nov 26 16:00:56 2015 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Nov 26 16:00:56 2015 +0100

    x86/vlapic: fixes for HVM code when running without a vlapic

    The HVM related code (SVM, VMX) generally assumed that a local apic is
    always present. With the introduction of a HVM mode were the local apic can
    be removed, some of this broken code paths arised.

    The SVM exit/resume paths unconditionally checked the state of the lapic,
    which is wrong if it's been disabled by hardware, fix this by adding the
    necessary checks. On the VMX side, make sure we don't add mappings for a
    local apic if it's disabled.

    In the generic vlapic code, add checks to prevent setting the TSC deadline
    timer if the lapic is disabled, and also prevent trying to inject interrupts
    from the PIC is the lapic is also disabled.

    Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Kevin Tian <kevin.tian@xxxxxxxxx>
---
 xen/arch/x86/hvm/svm/svm.c |   18 ++++++++++--------
 xen/arch/x86/hvm/vlapic.c  |    7 ++++++-
 xen/arch/x86/hvm/vmx/vmx.c |    4 +++-
 3 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index e2db4db..200a5df 100644
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -1035,6 +1035,7 @@ static void noreturn svm_do_resume(struct vcpu *v)
     struct vmcb_struct *vmcb = v->arch.hvm_svm.vmcb;
     bool_t debug_state = v->domain->debugger_attached;
     bool_t vcpu_guestmode = 0;
+    struct vlapic *vlapic = vcpu_vlapic(v);

     if ( nestedhvm_enabled(v->domain) && nestedhvm_vcpu_in_guestmode(v) )
         vcpu_guestmode = 1;
@@ -1059,14 +1060,14 @@ static void noreturn svm_do_resume(struct vcpu *v)
         hvm_asid_flush_vcpu(v);
     }

-    if ( !vcpu_guestmode )
+    if ( !vcpu_guestmode && !vlapic_hw_disabled(vlapic) )
     {
         vintr_t intr;

         /* Reflect the vlapic's TPR in the hardware vtpr */
         intr = vmcb_get_vintr(vmcb);
         intr.fields.tpr =
-            (vlapic_get_reg(vcpu_vlapic(v), APIC_TASKPRI) & 0xFF) >> 4;
+            (vlapic_get_reg(vlapic, APIC_TASKPRI) & 0xFF) >> 4;
         vmcb_set_vintr(vmcb, intr);
     }

@@ -2258,6 +2259,7 @@ void svm_vmexit_handler(struct cpu_user_regs *regs)
     int inst_len, rc;
     vintr_t intr;
     bool_t vcpu_guestmode = 0;
+    struct vlapic *vlapic = vcpu_vlapic(v);

     hvm_invalidate_regs_fields(regs);

@@ -2275,11 +2277,12 @@ void svm_vmexit_handler(struct cpu_user_regs *regs)
      * NB. We need to preserve the low bits of the TPR to make checked builds
      * of Windows work, even though they don't actually do anything.
      */
-    if ( !vcpu_guestmode ) {
+    if ( !vcpu_guestmode && !vlapic_hw_disabled(vlapic) )
+    {
         intr = vmcb_get_vintr(vmcb);
-        vlapic_set_reg(vcpu_vlapic(v), APIC_TASKPRI,
+        vlapic_set_reg(vlapic, APIC_TASKPRI,
                    ((intr.fields.tpr & 0x0F) << 4) |
-                   (vlapic_get_reg(vcpu_vlapic(v), APIC_TASKPRI) & 0x0F));
+                   (vlapic_get_reg(vlapic, APIC_TASKPRI) & 0x0F));
     }

     exit_reason = vmcb->exitcode;
@@ -2667,14 +2670,13 @@ void svm_vmexit_handler(struct cpu_user_regs *regs)
     }

   out:
-    if ( vcpu_guestmode )
-        /* Don't clobber TPR of the nested guest. */
+    if ( vcpu_guestmode || vlapic_hw_disabled(vlapic) )
         return;

     /* The exit may have updated the TPR: reflect this in the hardware vtpr */
     intr = vmcb_get_vintr(vmcb);
     intr.fields.tpr =
-        (vlapic_get_reg(vcpu_vlapic(v), APIC_TASKPRI) & 0xFF) >> 4;
+        (vlapic_get_reg(vlapic, APIC_TASKPRI) & 0xFF) >> 4;
     vmcb_set_vintr(vmcb, intr);
 }

diff --git a/xen/arch/x86/hvm/vlapic.c b/xen/arch/x86/hvm/vlapic.c
index 9b7c871..15d59f6 100644
--- a/xen/arch/x86/hvm/vlapic.c
+++ b/xen/arch/x86/hvm/vlapic.c
@@ -1037,7 +1037,9 @@ void vlapic_tdt_msr_set(struct vlapic *vlapic, uint64_t 
value)
     uint64_t guest_tsc;
     struct vcpu *v = vlapic_vcpu(vlapic);

-    /* may need to exclude some other conditions like vlapic->hw.disabled */
+    if ( vlapic_hw_disabled(vlapic) )
+        return;
+
     if ( !vlapic_lvtt_tdt(vlapic) )
     {
         HVM_DBG_LOG(DBG_LEVEL_VLAPIC_TIMER, "ignore tsc deadline msr write");
@@ -1113,6 +1115,9 @@ static int __vlapic_accept_pic_intr(struct vcpu *v)

 int vlapic_accept_pic_intr(struct vcpu *v)
 {
+    if ( vlapic_hw_disabled(vcpu_vlapic(v)) )
+        return 0;
+
     TRACE_2D(TRC_HVM_EMUL_LAPIC_PIC_INTR,
              (v == v->domain->arch.hvm_domain.i8259_target),
              v ? __vlapic_accept_pic_intr(v) : -1);
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 9ad6d82..3eeccbb 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -2429,9 +2429,11 @@ static void vmx_install_vlapic_mapping(struct vcpu *v)
 {
     paddr_t virt_page_ma, apic_page_ma;

-    if ( !cpu_has_vmx_virtualize_apic_accesses )
+    if ( v->domain->arch.hvm_domain.vmx.apic_access_mfn == 0 )
         return;

+    ASSERT(cpu_has_vmx_virtualize_apic_accesses);
+
     virt_page_ma = page_to_maddr(vcpu_vlapic(v)->regs_page);
     apic_page_ma = v->domain->arch.hvm_domain.vmx.apic_access_mfn;
     apic_page_ma <<= PAGE_SHIFT;
--
generated by git-patchbot for /home/xen/git/xen.git#master

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