[PATCH] xen/x86: Record xsave features in c->x86_capabilities

[Andrew Cooper <andrew.cooper3@citrix.com>]

Convert existing cpu_has_x??? to being functions of boot_cpu_data (matching
the prevailing style), and mask out unsupported features.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Shuai Ruan <shuai.ruan@linux.intel.com>

This is another patch from my feature levelling series which is being posted
early because of interactions with other code.

Shuai: This patch will interact with your xsaves series, although I hope it
will make your series easier.

Jan: I have opted for adding leaf 8 rather than reusing leaf 2, due to the
uncertainty with how this information is exposed in libxl.  This patch
introduces no change with how the information is represented in userspace.
---
 xen/arch/x86/cpu/common.c        |    2 +-
 xen/arch/x86/traps.c             |    5 +----
 xen/arch/x86/xstate.c            |   31 +++++++++++--------------------
 xen/include/asm-x86/cpufeature.h |   13 ++++++++++++-
 xen/include/asm-x86/xstate.h     |    8 ++------
 5 files changed, 27 insertions(+), 32 deletions(-)

diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c
index 35ef21b..0be0656 100644
--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -311,7 +311,7 @@ void __cpuinit identify_cpu(struct cpuinfo_x86 *c)
 		clear_bit(X86_FEATURE_XSAVE, boot_cpu_data.x86_capability);
 
 	if ( cpu_has_xsave )
-		xstate_init(c == &boot_cpu_data);
+		xstate_init(c);
 
 	/*
 	 * The vendor-specific functions might have changed features.  Now
diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index 9f5a6c6..07feb6d 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -935,10 +935,7 @@ void pv_cpuid(struct cpu_user_regs *regs)
             goto unsupported;
         if ( regs->_ecx == 1 )
         {
-            a &= XSTATE_FEATURE_XSAVEOPT |
-                 XSTATE_FEATURE_XSAVEC |
-                 (cpu_has_xgetbv1 ? XSTATE_FEATURE_XGETBV1 : 0) |
-                 (cpu_has_xsaves ? XSTATE_FEATURE_XSAVES : 0);
+            a &= boot_cpu_data.x86_capability[X86_FEATURE_XSAVEOPT / 32];
             if ( !cpu_has_xsaves )
                 b = c = d = 0;
         }
diff --git a/xen/arch/x86/xstate.c b/xen/arch/x86/xstate.c
index d5f5e3b..3e107a2 100644
--- a/xen/arch/x86/xstate.c
+++ b/xen/arch/x86/xstate.c
@@ -14,11 +14,6 @@
 #include <asm/xstate.h>
 #include <asm/asm_defns.h>
 
-static bool_t __read_mostly cpu_has_xsaveopt;
-static bool_t __read_mostly cpu_has_xsavec;
-bool_t __read_mostly cpu_has_xgetbv1;
-bool_t __read_mostly cpu_has_xsaves;
-
 /*
  * Maximum size (in byte) of the XSAVE/XRSTOR save area required by all
  * the supported and enabled features on the processor, including the
@@ -281,8 +276,9 @@ unsigned int xstate_ctxt_size(u64 xcr0)
 }
 
 /* Collect the information of processor's extended state */
-void xstate_init(bool_t bsp)
+void xstate_init(struct cpuinfo_x86 *c)
 {
+    bool_t bsp = c == &boot_cpu_data;
     u32 eax, ebx, ecx, edx;
     u64 feature_mask;
 
@@ -325,20 +321,15 @@ void xstate_init(bool_t bsp)
 
     /* Check extended XSAVE features. */
     cpuid_count(XSTATE_CPUID, 1, &eax, &ebx, &ecx, &edx);
-    if ( bsp )
-    {
-        cpu_has_xsaveopt = !!(eax & XSTATE_FEATURE_XSAVEOPT);
-        cpu_has_xsavec = !!(eax & XSTATE_FEATURE_XSAVEC);
-        /* XXX cpu_has_xgetbv1 = !!(eax & XSTATE_FEATURE_XGETBV1); */
-        /* XXX cpu_has_xsaves = !!(eax & XSTATE_FEATURE_XSAVES); */
-    }
-    else
-    {
-        BUG_ON(!cpu_has_xsaveopt != !(eax & XSTATE_FEATURE_XSAVEOPT));
-        BUG_ON(!cpu_has_xsavec != !(eax & XSTATE_FEATURE_XSAVEC));
-        /* XXX BUG_ON(!cpu_has_xgetbv1 != !(eax & XSTATE_FEATURE_XGETBV1)); */
-        /* XXX BUG_ON(!cpu_has_xsaves != !(eax & XSTATE_FEATURE_XSAVES)); */
-    }
+
+    /* Mask out features not currently understood by Xen. */
+    eax &= (cpufeat_mask(X86_FEATURE_XSAVEOPT) |
+            cpufeat_mask(X86_FEATURE_XSAVEC));
+
+    c->x86_capability[X86_FEATURE_XSAVEOPT / 32] = eax;
+
+    if ( !bsp )
+        BUG_ON(eax != boot_cpu_data.x86_capability[X86_FEATURE_XSAVEOPT / 32]);
 }
 
 static bool_t valid_xcr0(u64 xcr0)
diff --git a/xen/include/asm-x86/cpufeature.h b/xen/include/asm-x86/cpufeature.h
index 9a01563..aa228db 100644
--- a/xen/include/asm-x86/cpufeature.h
+++ b/xen/include/asm-x86/cpufeature.h
@@ -9,7 +9,7 @@
 #define __ASM_I386_CPUFEATURE_H
 #endif
 
-#define NCAPINTS	8	/* N 32-bit words worth of info */
+#define NCAPINTS	9	/* N 32-bit words worth of info */
 
 /* Intel-defined CPU features, CPUID level 0x00000001 (edx), word 0 */
 #define X86_FEATURE_FPU		(0*32+ 0) /* Onboard FPU */
@@ -154,6 +154,12 @@
 #define X86_FEATURE_ADX		(7*32+19) /* ADCX, ADOX instructions */
 #define X86_FEATURE_SMAP	(7*32+20) /* Supervisor Mode Access Prevention */
 
+/* Intel-defined CPU features, CPUID level 0x0000000D:1 (eax), word 8 */
+#define X86_FEATURE_XSAVEOPT	(8*32+ 0)
+#define X86_FEATURE_XSAVEC	(8*32+ 1)
+#define X86_FEATURE_XGETBV1	(8*32+ 2)
+#define X86_FEATURE_XSAVES	(8*32+ 3)
+
 #if !defined(__ASSEMBLY__) && !defined(X86_FEATURES_ONLY)
 #include <xen/bitops.h>
 
@@ -219,6 +225,11 @@
 
 #define cpu_has_cx16            boot_cpu_has(X86_FEATURE_CX16)
 
+#define cpu_has_xsaveopt	boot_cpu_has(X86_FEATURE_XSAVEOPT)
+#define cpu_has_xsavec		boot_cpu_has(X86_FEATURE_XSAVEC)
+#define cpu_has_xgetbv1		boot_cpu_has(X86_FEATURE_XGETBV1)
+#define cpu_has_xsaves		boot_cpu_has(X86_FEATURE_XSAVES)
+
 enum _cache_type {
     CACHE_TYPE_NULL = 0,
     CACHE_TYPE_DATA = 1,
diff --git a/xen/include/asm-x86/xstate.h b/xen/include/asm-x86/xstate.h
index 4c690db..f0d8f0b 100644
--- a/xen/include/asm-x86/xstate.h
+++ b/xen/include/asm-x86/xstate.h
@@ -9,16 +9,13 @@
 #define __ASM_XSTATE_H
 
 #include <xen/types.h>
+#include <asm/cpufeature.h>
 
 #define FCW_DEFAULT               0x037f
 #define FCW_RESET                 0x0040
 #define MXCSR_DEFAULT             0x1f80
 
 #define XSTATE_CPUID              0x0000000d
-#define XSTATE_FEATURE_XSAVEOPT   (1 << 0)    /* sub-leaf 1, eax[bit 0] */
-#define XSTATE_FEATURE_XSAVEC     (1 << 1)    /* sub-leaf 1, eax[bit 1] */
-#define XSTATE_FEATURE_XGETBV1    (1 << 2)    /* sub-leaf 1, eax[bit 2] */
-#define XSTATE_FEATURE_XSAVES     (1 << 3)    /* sub-leaf 1, eax[bit 3] */
 
 #define XCR_XFEATURE_ENABLED_MASK 0x00000000  /* index of XCR0 */
 
@@ -43,7 +40,6 @@
 #define XSTATE_LAZY    (XSTATE_ALL & ~XSTATE_NONLAZY)
 
 extern u64 xfeature_mask;
-extern bool_t cpu_has_xsaves, cpu_has_xgetbv1;
 
 /* extended state save area */
 struct __packed __attribute__((aligned (64))) xsave_struct
@@ -91,7 +87,7 @@ struct __packed __attribute__((aligned (64))) xsave_struct
 /* extended state init and cleanup functions */
 void xstate_free_save_area(struct vcpu *v);
 int xstate_alloc_save_area(struct vcpu *v);
-void xstate_init(bool_t bsp);
+void xstate_init(struct cpuinfo_x86 *c);
 unsigned int xstate_ctxt_size(u64 xcr0);
 
 #endif /* __ASM_XSTATE_H */
-- 
1.7.10.4