[Xen-devel] [PATCH 23/27] x86/cpuid: Move all leaf 7 handling into guest_cpuid()

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

All per-domain policy data concerning leaf 7 is accurate.  Handle it all in
guest_cpuid() by reading out of the raw array block, and introduing a dynamic
adjustment for OSPKE.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
---
 xen/arch/x86/cpuid.c        | 41 +++++++++++++++++++++++++++++++++++++----
 xen/arch/x86/hvm/hvm.c      | 17 ++++-------------
 xen/arch/x86/traps.c        | 28 ++++------------------------
 xen/include/asm-x86/cpuid.h |  2 ++
 4 files changed, 47 insertions(+), 41 deletions(-)

diff --git a/xen/arch/x86/cpuid.c b/xen/arch/x86/cpuid.c
index d140482..9181fc7 100644
--- a/xen/arch/x86/cpuid.c
+++ b/xen/arch/x86/cpuid.c
@@ -339,6 +339,7 @@ int init_domain_cpuid_policy(struct domain *d)
 void guest_cpuid(const struct vcpu *v, unsigned int leaf,
                  unsigned int subleaf, struct cpuid_leaf *res)
 {
+    const struct vcpu *curr = current;
     const struct domain *d = v->domain;
     const struct cpuid_policy *p = d->arch.cpuid;
 
@@ -348,6 +349,7 @@ void guest_cpuid(const struct vcpu *v, unsigned int leaf,
      * First pass:
      * - Dispatch the virtualised leaves to their respective handlers.
      * - Perform max_leaf/subleaf calculations, maybe returning early.
+     * - Fill in *res for leaves no longer handled on the legacy path.
      */
     switch ( leaf )
     {
@@ -358,17 +360,20 @@ void guest_cpuid(const struct vcpu *v, unsigned int leaf,
 #endif
         if ( leaf > p->basic.max_leaf )
             return;
-        break;
+        goto legacy;
 
     case 0x7:
         if ( subleaf > p->feat.max_subleaf )
             return;
+
+        BUG_ON(subleaf >= ARRAY_SIZE(p->feat.raw));
+        *res = p->feat.raw[subleaf];
         break;
 
     case 0xd:
         if ( subleaf > ARRAY_SIZE(p->xstate.raw) )
             return;
-        break;
+        goto legacy;
 
     case 0x40000000 ... 0x400000ff:
         if ( is_viridian_domain(d) )
@@ -380,14 +385,42 @@ void guest_cpuid(const struct vcpu *v, unsigned int leaf,
     case 0x80000000 ... 0x80000000 + CPUID_GUEST_NR_EXTD - 1:
         if ( leaf > p->extd.max_leaf )
             return;
-        break;
+        goto legacy;
 
     default:
         return;
     }
 
+    /* Skip dynamic adjustments if we are in the wrong context. */
+    if ( v != curr )
+        return;
+
+    /*
+     * Second pass:
+     * - Dynamic adjustments
+     */
+    switch ( leaf )
+    {
+    case 0x7:
+        switch ( subleaf )
+        {
+        case 0:
+            /* OSPKE clear in policy.  Fast-forward CR4 back in. */
+            if ( (is_pv_vcpu(v)
+                  ? v->arch.pv_vcpu.ctrlreg[4]
+                  : v->arch.hvm_vcpu.guest_cr[4]) & X86_CR4_PKE )
+                res->c |= cpufeat_mask(X86_FEATURE_OSPKE);
+            break;
+        }
+        break;
+    }
+
+    /* Done. */
+    return;
+
+ legacy:
     /* {pv,hvm}_cpuid() have this expectation. */
-    ASSERT(v == current);
+    ASSERT(v == curr);
 
     if ( is_pv_vcpu(v) || is_pvh_vcpu(v) )
     {
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 1dd92e3..4ded533 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -3354,19 +3354,6 @@ void hvm_cpuid(unsigned int input, unsigned int *eax, 
unsigned int *ebx,
 
         break;
 
-    case 0x7:
-        if ( count == 0 )
-        {
-            *ebx = d->arch.cpuid->feat._7b0;
-            *ecx = d->arch.cpuid->feat._7c0;
-            *edx = d->arch.cpuid->feat._7d0;
-
-            /* OSPKE clear in policy.  Fast-forward CR4 back in. */
-            if ( v->arch.hvm_vcpu.guest_cr[4] & X86_CR4_PKE )
-                *ecx |= cpufeat_mask(X86_FEATURE_OSPKE);
-        }
-        break;
-
     case 0xb:
         /* Fix the x2APIC identifier. */
         *edx = v->vcpu_id * 2;
@@ -3543,6 +3530,10 @@ void hvm_cpuid(unsigned int input, unsigned int *eax, 
unsigned int *ebx,
         else
             *eax = 0;
         break;
+
+    case 0x7:
+        ASSERT_UNREACHABLE();
+        /* Now handled in guest_cpuid(). */
     }
 }
 
diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index aed96c3..e2669b1 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -1180,30 +1180,6 @@ void pv_cpuid(struct cpu_user_regs *regs)
         }
         break;
 
-    case 0x00000007:
-        if ( subleaf == 0 )
-        {
-            b = currd->arch.cpuid->feat._7b0;
-            c = currd->arch.cpuid->feat._7c0;
-            d = currd->arch.cpuid->feat._7d0;
-
-            if ( !is_pvh_domain(currd) )
-            {
-                /*
-                 * Delete the PVH condition when HVMLite formally replaces PVH,
-                 * and HVM guests no longer enter a PV codepath.
-                 */
-
-                /* OSPKE clear in policy.  Fast-forward CR4 back in. */
-                if ( curr->arch.pv_vcpu.ctrlreg[4] & X86_CR4_PKE )
-                    c |= cpufeat_mask(X86_FEATURE_OSPKE);
-            }
-        }
-        else
-            b = c = d = 0;
-        a = 0;
-        break;
-
     case 0x0000000a: /* Architectural Performance Monitor Features (Intel) */
         if ( boot_cpu_data.x86_vendor != X86_VENDOR_INTEL ||
              !vpmu_enabled(curr) )
@@ -1305,6 +1281,10 @@ void pv_cpuid(struct cpu_user_regs *regs)
     unsupported:
         a = b = c = d = 0;
         break;
+
+    case 0x7:
+        ASSERT_UNREACHABLE();
+        /* Now handled in guest_cpuid(). */
     }
 
     regs->rax = a;
diff --git a/xen/include/asm-x86/cpuid.h b/xen/include/asm-x86/cpuid.h
index 7363263..c7e9df5 100644
--- a/xen/include/asm-x86/cpuid.h
+++ b/xen/include/asm-x86/cpuid.h
@@ -81,12 +81,14 @@ struct cpuid_policy
      *   - {xcr0,xss}_{high,low}
      *
      * - Guest appropriate:
+     *   - All of the feat union
      *   - max_{,sub}leaf
      *   - All FEATURESET_* words
      *
      * Per-domain objects:
      *
      * - Guest accurate:
+     *   - All of the feat union
      *   - max_{,sub}leaf
      *   - All FEATURESET_* words
      *
-- 
2.1.4


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel