[Xen-devel] [PATCH v2 06/10] x86/cpuid: Handle leaf 0x6 in guest_cpuid()

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

The thermal/performance leaf was previously hidden from HVM guests, but fully
visible to PV guests.  Most of the leaf refers to MSR availability, and there
is nothing an unprivileged PV guest can do with the information, so hide the
leaf entirely.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>

v2:
 * Don't leak any state into the hardware domain.
---
 xen/arch/x86/cpuid.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/cpuid.c b/xen/arch/x86/cpuid.c
index 11e50e9..8585d94 100644
--- a/xen/arch/x86/cpuid.c
+++ b/xen/arch/x86/cpuid.c
@@ -168,6 +168,7 @@ static void recalculate_misc(struct cpuid_policy *p)
     p->basic.apic_id = 0; /* Dynamic. */
 
     p->basic.raw[0x5] = EMPTY_LEAF; /* MONITOR not exposed to guests. */
+    p->basic.raw[0x6] = EMPTY_LEAF; /* Therm/Power not exposed to guests. */
 
     p->basic.raw[0x8] = EMPTY_LEAF;
     p->basic.raw[0xc] = EMPTY_LEAF;
@@ -643,8 +644,7 @@ static void pv_cpuid(uint32_t leaf, uint32_t subleaf, 
struct cpuid_leaf *res)
         *res = EMPTY_LEAF;
         break;
 
-    case 0x0 ... 0x5:
-    case 0x7 ... 0x9:
+    case 0x0 ... 0x9:
     case 0xc ... XSTATE_CPUID:
     case 0x80000000 ... 0xffffffff:
         ASSERT_UNREACHABLE();
@@ -678,8 +678,7 @@ static void hvm_cpuid(uint32_t leaf, uint32_t subleaf, 
struct cpuid_leaf *res)
             res->a = (res->a & ~0xff) | 3;
         break;
 
-    case 0x0 ... 0x5:
-    case 0x7 ... 0x9:
+    case 0x0 ... 0x9:
     case 0xc ... XSTATE_CPUID:
     case 0x80000000 ... 0xffffffff:
         ASSERT_UNREACHABLE();
@@ -739,7 +738,7 @@ void guest_cpuid(const struct vcpu *v, uint32_t leaf,
             goto legacy;
 
         case 0x0 ... 0x3:
-        case 0x5:
+        case 0x5 ... 0x6:
         case 0x8 ... 0x9:
         case 0xc:
             *res = p->basic.raw[leaf];
-- 
2.1.4


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