[Xen-changelog] [xen master] x86/cpuid: Handle leaf 0x8000001c in guest_cpuid()

[patchbot@xxxxxxx]

commit 8cb4bae1c1aa13ddb3ba11dda3f593b1f7f0ed80
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Fri Jan 20 13:56:10 2017 +0000
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Wed Jan 25 10:26:29 2017 +0000

    x86/cpuid: Handle leaf 0x8000001c in guest_cpuid()
    
    Leaf 0x8000001c contains LWP information.  edx contains hardware supported
    features (and is clamped against the maximum), while ecx and ebx contain
    various properties of the implementation.  eax is entirely dynamic, 
depending
    on xcr0 and MSR_LWP_CFG.
    
    The call to guest_cpuid() in svm_update_lwp_cfg() can now be replaced by
    reading the data straight out of the cpuid_policy block.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/cpuid.c       | 34 ++++++++++++++++------------------
 xen/arch/x86/hvm/svm/svm.c |  5 +----
 2 files changed, 17 insertions(+), 22 deletions(-)

diff --git a/xen/arch/x86/cpuid.c b/xen/arch/x86/cpuid.c
index dc4ddd5..97a3dd4 100644
--- a/xen/arch/x86/cpuid.c
+++ b/xen/arch/x86/cpuid.c
@@ -213,6 +213,8 @@ static void recalculate_misc(struct cpuid_policy *p)
         zero_leaves(p->extd.raw, 0xb, 0x18);
 
         p->extd.raw[0x1b] = EMPTY_LEAF; /* IBS - not supported. */
+
+        p->extd.raw[0x1c].a = 0; /* LWP.a entirely dynamic. */
         break;
     }
 }
@@ -516,6 +518,11 @@ void recalculate_cpuid_policy(struct domain *d)
 
     if ( !p->extd.page1gb )
         p->extd.raw[0x19] = EMPTY_LEAF;
+
+    if ( p->extd.lwp )
+        p->extd.raw[0x1c].d &= max->extd.raw[0x1c].d;
+    else
+        p->extd.raw[0x1c] = EMPTY_LEAF;
 }
 
 int init_domain_cpuid_policy(struct domain *d)
@@ -729,7 +736,6 @@ static void pv_cpuid(uint32_t leaf, uint32_t subleaf, 
struct cpuid_leaf *res)
 
     case 0x00000005: /* MONITOR/MWAIT */
     case 0x0000000b: /* Extended Topology Enumeration */
-    case 0x8000001c: /* Light Weight Profiling */
     unsupported:
         *res = EMPTY_LEAF;
         break;
@@ -738,7 +744,7 @@ static void pv_cpuid(uint32_t leaf, uint32_t subleaf, 
struct cpuid_leaf *res)
     case 0x2 ... 0x3:
     case 0x7 ... 0x9:
     case 0xc ... XSTATE_CPUID:
-    case 0x80000000 ... 0x8000001b:
+    case 0x80000000 ... 0x8000001c:
         ASSERT_UNREACHABLE();
         /* Now handled in guest_cpuid(). */
     }
@@ -816,25 +822,11 @@ static void hvm_cpuid(uint32_t leaf, uint32_t subleaf, 
struct cpuid_leaf *res)
             res->a = (res->a & ~0xff) | 3;
         break;
 
-    case 0x8000001c:
-        if ( !cpu_has_svm )
-        {
-            *res = EMPTY_LEAF;
-            break;
-        }
-
-        if ( cpu_has_lwp && (v->arch.xcr0 & XSTATE_LWP) )
-            /* Turn on available bit and other features specified in lwp_cfg. 
*/
-            res->a = (res->d & v->arch.hvm_svm.guest_lwp_cfg) | 1;
-        else
-            res->a = 0;
-        break;
-
     case 0x0:
     case 0x2 ... 0x3:
     case 0x7 ... 0x9:
     case 0xc ... XSTATE_CPUID:
-    case 0x80000000 ... 0x8000001b:
+    case 0x80000000 ... 0x8000001c:
         ASSERT_UNREACHABLE();
         /* Now handled in guest_cpuid(). */
     }
@@ -917,7 +909,7 @@ void guest_cpuid(const struct vcpu *v, uint32_t leaf,
         default:
             goto legacy;
 
-        case 0x80000000 ... 0x8000001b:
+        case 0x80000000 ... 0x8000001c:
             *res = p->extd.raw[leaf & 0xffff];
             break;
         }
@@ -1027,6 +1019,12 @@ void guest_cpuid(const struct vcpu *v, uint32_t leaf,
                 res->d |= cpufeat_mask(X86_FEATURE_MTRR);
         }
         break;
+
+    case 0x8000001c:
+        if ( (v->arch.xcr0 & XSTATE_LWP) && cpu_has_svm )
+            /* Turn on available bit and other features specified in lwp_cfg. 
*/
+            res->a = (res->d & v->arch.hvm_svm.guest_lwp_cfg) | 1;
+        break;
     }
 
     /* Done. */
diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index e8ef88d..01c7b58 100644
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -931,13 +931,10 @@ static int svm_update_lwp_cfg(struct vcpu *v, uint64_t 
msr_content)
 
     if ( xsave_enabled(v) && cpu_has_lwp )
     {
-        struct cpuid_leaf res;
-
-        guest_cpuid(v, 0x8000001c, 0, &res);
         msr_low = (uint32_t)msr_content;
         
         /* generate #GP if guest tries to turn on unsupported features. */
-        if ( msr_low & ~res.d)
+        if ( msr_low & ~v->domain->arch.cpuid->extd.raw[0x1c].d )
             return -1;
 
         v->arch.hvm_svm.guest_lwp_cfg = msr_content;
--
generated by git-patchbot for /home/xen/git/xen.git#master

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