[Xen-devel] [PATCH v4 2/2] x86/vpmu: Disable VPMU if guest's CPUID indicates no PMU support

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

When toolstack overrides Intel CPUID leaf 0xa's PMU version with an
invalid value VPMU should not be available to the guest.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/cpu/vpmu_intel.c |  4 ++++
 xen/arch/x86/domctl.c         | 14 ++++++++++++++
 xen/include/asm-x86/cpuid.h   | 12 ++++++++++++
 3 files changed, 30 insertions(+)

diff --git a/xen/arch/x86/cpu/vpmu_intel.c b/xen/arch/x86/cpu/vpmu_intel.c
index 0ce68f1..626bed5 100644
--- a/xen/arch/x86/cpu/vpmu_intel.c
+++ b/xen/arch/x86/cpu/vpmu_intel.c
@@ -883,6 +883,10 @@ int vmx_vpmu_initialise(struct vcpu *v)
     if ( vpmu_mode == XENPMU_MODE_OFF )
         return 0;
 
+    if ( v->domain->arch.cpuid->basic.pmu_version <= 1 ||
+         v->domain->arch.cpuid->basic.pmu_version >= 5 )
+        return -EINVAL;
+
     if ( (arch_pmc_cnt + fixed_pmc_cnt) == 0 )
         return -EINVAL;
 
diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index d5f8d2f..02b48e8 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -252,6 +252,20 @@ static int update_domain_cpuid_info(struct domain *d,
         }
         break;
 
+    case 0xa:
+        if ( boot_cpu_data.x86_vendor != X86_VENDOR_INTEL )
+            break;
+
+        /* If PMU version is zero then the guest doesn't have VPMU */
+        if ( p->basic.pmu_version == 0 )
+        {
+            struct vcpu *v;
+
+            for_each_vcpu ( d, v )
+                vpmu_destroy(v);
+        }
+        break;
+
     case 0xd:
         if ( ctl->input[1] != 1 )
             break;
diff --git a/xen/include/asm-x86/cpuid.h b/xen/include/asm-x86/cpuid.h
index 6d1990b..aa482b7 100644
--- a/xen/include/asm-x86/cpuid.h
+++ b/xen/include/asm-x86/cpuid.h
@@ -122,6 +122,18 @@ struct cpuid_policy
 
             /* Leaf 0x2 - TLB/Cache/Prefetch. */
             uint8_t l2_nr_queries; /* Documented as fixed to 1. */
+            uint8_t l2_desc[15];
+
+            uint64_t :64, :64; /* Leaf 0x3 - PSN. */
+            uint64_t :64, :64; /* Leaf 0x4 - Structured Cache. */
+            uint64_t :64, :64; /* Leaf 0x5 - MONITOR. */
+            uint64_t :64, :64; /* Leaf 0x6 - Therm/Perf. */
+            uint64_t :64, :64; /* Leaf 0x7 - Structured Features. */
+            uint64_t :64, :64; /* Leaf 0x8 - rsvd */
+            uint64_t :64, :64; /* Leaf 0x9 - DCA */
+
+            /* Leaf 0xa - Intel PMU. */
+            uint8_t pmu_version;
         };
     } basic;
 
-- 
1.8.3.1


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